WO1999000985A1

WO1999000985A1 - Image encoding method and image decoding method

Info

Publication number: WO1999000985A1
Application number: PCT/JP1998/002835
Authority: WO
Inventors: Shinya Kadono
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 1997-06-27
Filing date: 1998-06-25
Publication date: 1999-01-07
Also published as: JPH1118092A

Abstract

An image encoding method and an image decoding method implemented by using, as shown in the figure, a frame/field decision circuit (1) which decides whether the downsampling of input image signals Sin is performed for every frame or for every field and outputs a mode signal Sm in accordance with the decision result, a downsampling device (11a) which downsamples the input image signals Sin for every frame, and a downsampling device (12a) which downsamples the input image signals Sin for every field, thus selecting one of the ouputs of both the downsampling devices (11a) and (12a) in accordance with the mode signal Sm to perform blocking and image encoding. As a result, when interlaced image signals are encoded, proper downsampling can be selected in accordance with the type of image, still image or dynamic image, so that the image quality deterioration caused by the encoding accompagnied by the downsampling can be avoided.

Description

Description Image coding method and image decoding method

The present invention relates to an image encoding method and an image decoding method, an image encoding device and an image decoding device, and a data recording medium, and particularly to an interlaced image signal and an encoding process with downsampling, and The present invention relates to a decoding process involving up-sampling of an interlaced image signal that has been subjected to such coding. Background art

In recent years, the multimedia era, in which voices, images, and other data are handled in an integrated manner, has entered the multimedia era. It has come to be taken up as. Generally, multimedia refers to not only characters, but also figures, sounds, and especially images, etc., that are associated simultaneously.However, in order for multimedia information to be used for the conventional information media, the information must be converted to digital format. Is an essential condition. However, when the amount of information held by each of the above information media is estimated as the amount of digital information, the amount of information per character is 1-2 bytes per character, whereas the amount of information per character is 6 bytes per second for voice. k bits (telephone quality), and more than 1 Mbits per second (current television reception quality) for moving images, it is not possible to handle the vast amount of information in digital form in the above information media. It's not a target. For example, videophones have already been put into practical use by the Integrated Services Digital Network (ISDN), which has a transmission rate of 64 kbps to 1.5 Mbps. This is not possible.

What is needed is information compression technology. For example, in the case of videophones, the H.261 standard video compression technology internationally standardized by the ITUT (International Telecommunication Union Telecommunication Standardization Sector). Used. Also, information on the MPEG 1 standard According to the information compression technology, it is also possible to put image information along with audio information on a normal music CD (compact, disc).

Here, MPEG (Moving Picture Experts Group) is an international standard for data compression of moving images, and MPEG 1 reduces video data up to 1.5 Mbps, that is, TV signal information to about 1/100. It is a standard to compress up to. In addition, since the transmission speed for the MPEG-1 standard is mainly limited to about 1.5 Mbps, MPEG2, which has been standardized to meet the demand for even higher image quality, uses moving image data. Is compressed to 2 to 15Mbps.

Furthermore, at present, the working group (ISO / IEC JTC1 / SC29 / WG11), which has promoted the standardization of MPEG1 and MPEG2, has made it possible to perform encoding and other signal processing on an object-by-object basis. MPEG4, which realizes new functions necessary for the times, is being standardized. At first, MPEG4 aimed to standardize the coding method of low bit rate, but now, the method that is trying to standardize is the coding processing of high bit rate for interlaced image signals. It has been extended to more general coding methods.

In the encoding and decoding processing conforming to the MPEG 4 standard, in order to improve the encoding efficiency, the input image signal is down-sampled and encoded, and the transmitted image encoded signal is decoded. The method of upsampling is adopted.

Briefly described below, FIG. 14 is a diagram conceptually showing such encoding and decoding processing in MPEG4. As shown in the figure, first, the input encoded image signal ( The input image signal) Sin is first downsampled, the downsampled image signal (downsampled image signal) Sds is encoded, and then the encoded image encoded signal Sc is transmitted. By down-sampling the input image signal S in this way, the amount of pixel information included in the input image signal S in to be encoded is reduced. That is, the number of pixels of the display image obtained from the input image signal S in decreases. As a result, the number of coding bits for the image signal can be reduced.

On the other hand, the transmitted image coded signal Sc is subjected to a decoding process, and the decoded image signal Se is up-sampled. This allows the encoded image signal (input) An image decoding signal having the same resolution as that of S in can be obtained as an up-sampled image signal Su.

The above-described up-sampling processing and down-sampling processing of the interlaced image signal include a method performed on a field-by-field basis and a method performed on a frame-by-frame basis.

FIG. 15 is a block diagram for explaining the configuration of a conventional image encoding device. FIG. 15 (a) is an example of a configuration in which an image signal is downsampled at the field ^, and in FIG. 15 (a), 30a is a predetermined size for dividing an interlaced image signal into display screens. This is an image encoding device that performs an encoding process involving down-sampling on a block image signal S b 1 obtained by blocking each display block (hereinafter, also simply referred to as a block). It has a field unit down-sampling unit 31 for down-sampling the blocked image signal S b 1 in field units, and an image encoding unit 33 for performing an encoding process on the output S dd 1. Note that the blocked image signal S b1 is composed of pixel values of a plurality of pixels located in each of the display blocks.

In the image coding apparatus 30a having such a configuration, first, when the block image signal Sb1 is input as an image signal, the block image signal Sb1 is converted into a field unit by the downsampler 31. Downsampled. That is, the down-sampling device 31 performs a down-sampling process by grouping the image signals corresponding to one block in the field screen.

Subsequently, the output Sdd1 of the down-sampler 31 is encoded by the image encoding unit 33 in block units, and an image encoded signal Sc1 is output.

FIG. 15 (b) is an example of a configuration in which the image signal is down-sampled in frame units.In FIG. 15 (b), 3 Ob is a blocked image obtained by blocking the interlaced image signal. This is an image encoding device that performs an encoding process involving downsampling on the signal Sb2. The image encoding device 30 b includes a frame-unit down-sampling unit 32 for down-sampling the blocked image signal S b 2 on a frame-by-frame basis, and a surface image encoding unit that performs an encoding process on the output S dd 2. And 3 parts. Note that the blocked image signal S b 2 is also similar to the blocked image signal S b 1. It is composed of pixel values of a plurality of pixels located in one block.

In the image encoding device 30b having such a configuration, first, when the blocked image signal Sb2 is input as an image signal, the blocked image signal Sb2 is converted into a frame unit by the downsampler 32. Downsampled. In other words, the down-sampler 32 combines the blocked image signal Sb2 with the blocks at the same position of the two field screens that constitute one frame screen, and obtains a combined blocked image signal. The process of downsampling the composite block image signal is performed for each frame.

Subsequently, the output Sdd 2 of the down-sampler 32 is encoded by the image encoding unit 33 on a block basis, and an image encoded signal Sc 2 is output.

FIG. 16 is a block diagram for explaining the configuration of a conventional image decoding apparatus that performs a decoding process involving an upsample. FIG. 16 (a) shows an image decoding apparatus configured to upsample an image signal in field units. In FIG. 16 (a), reference numeral 40a denotes an image decoding device for decoding the image coded signal Sc1 coded by the image coding device 30a. The image decoding device 40 includes an image decoding unit 41 that decodes the image coded signal c 1 for each block, and a field unit that performs a web sample of the decoded signal Se 11 on a field basis. It has a web sample section 42.

In the image encoding device 40 a having such a configuration, first, when the image encoded signal S c1 encoded by the image encoding device 30 a is input, the image encoded signal S c 1 Is decoded in block units by the image decoding unit 41, and the image decoding signal S e 11 output from the image decoding unit 41 is further converted to field units by the field up-sampling unit 4 2. And an up-sampled image decoded signal S e1 is output.

FIG. 16 (b) shows an image decoding apparatus configured to upsample an image signal in frame units.In FIG. 16 (b), 4 Ob is calculated by the image coding apparatus 30b. This is an image decoding device that decodes the encoded image encoded signal Sc2. The image decoding device 40b includes an image decoding unit 41 that decodes the image encoded signal Sc2 for each block, and an amplifier sampler that decodes the image decoded signal Se22 in frame units. And a frame unit upsampling section 43 to be pulled.

In the image decoding device 40 b having such a configuration, when the image encoded signal S c 2 encoded by the image encoding device 30 b is input, the image encoded signal St 2 The image is decoded by the image decoding unit 41 in block units, and the image decoding signal Se 22 output from the image decoding unit 41 is increased in field units by the frame unit upsampler 43. It is sampled and an up-sampled dual-image decoded signal S e 2 is output.

The conventional image encoding apparatus 30a has a configuration in which the input image signal that has been blocked is used as an input, but if the input image signal is not blocked, the down-sampling processing is performed. Before or after downsampling, it is necessary to perform processing to block the input image signal, that is, block the input image signal so as to correspond to a plurality of display blocks that divide the display screen.

Here, the image coding apparatus configured to block before down-sampling processing is performed by the down-sampling of the image coding apparatuses 30a and 30b shown in FIGS. 15 (a) and 15 (b). A block circuit provided before the pull section is provided.

Further, the image coding apparatus configured to block after the down-sampling processing includes a down-sampling unit in the image coding apparatuses 30a and 30b shown in FIGS. 15 (a) and 15 (b). It is provided with a blocking circuit provided between the image encoding unit and the image encoding unit.

FIGS. 17 (a) and 17 (b) are block diagrams each showing a configuration of an image encoding device that performs an encoding process on an image signal that is not blocked. In FIG. 17 (a), reference numeral 210a denotes an image coding apparatus having a configuration in which the input image signal Sin is downsampled in field units and then subjected to block processing. This image encoding device 210a is a field unit downsampler 11 that downsamples the input image signal Sin on a field unit basis, and its downsampled output Sd1 is blocked. A block circuit 21 for grouping S d 1 into display blocks (blocks) of a predetermined size that divides a one-field screen, and an output S b 1 of each block are coded for each block to generate an image coded signal S c And an image encoding circuit 30 that outputs 1. Five

6 In the image coding apparatus 210a having such a configuration, first, the input image signal Sin is downsampled in field units by the field unit downsampler 11, and then the above-mentioned The down-sampled output S d1 is blocked, and the blocked output S b1 is coded by the image coding circuit 30 in block units, and is output as a coded image signal S c1.

In FIG. 17 (b), reference numeral 210b denotes an image coding apparatus configured to perform downsampling processing after downsampling the input image signal S in frame units. The image encoding device 210b includes a frame-unit downsampler 12 that downsamples the input image signal Sin in frame units, and blocks the downsampled output Sd2, that is, the downsampled output Sd 2 is divided into display blocks (blocks) of a predetermined size that divide one frame screen, and the output S b 2 is coded for each block to generate an image coded signal S c 2. And an image encoding circuit 30 for outputting.

In the image coding apparatus 220 a having such a configuration, first, the input image signal S in is down-sampled in frame units by the frame-by-frame down-sampler 12, and the down-sampling ί symbol S d 2 is divided into blocks. The signal is divided into blocks by the circuit 22, and the block signal S b 2 is further encoded by the image encoding circuit 30 in units of blocks, and output as an image encoded signal Sc 2.

FIG. 18 is a diagram for explaining an image decoding device that decodes an image signal encoded by the image encoding device shown in FIG. 17, and FIG. FIG. 3 is a block diagram showing the configuration of an image decoding apparatus that performs upsampling in field units. In FIG. 18 (a), reference numeral 210b denotes an image decoding device for decoding the image signal encoded by the image encoding device 210a, and this image decoding device 21 0 b is an image decoding circuit 40 for decoding the image encoded signal S c 1 transmitted from the image encoding device 210 a, and inversely blocks the decoded signal S e 1 That is, a deblocking circuit 51 for converting the field image signal Sr1 into a field image signal Sr1 corresponding to the scanning line structure of the field screen, and a field unit upsampler 6〗 for upsampling the field image signal Sr1 in field units. And outputs the up-sampled signal S u1. In the image decoding device 210b having such a configuration, upon receiving the image encoded signal Sc1 encoded by the image encoding device 210a, the image encoded signal Sc1 is converted to the image encoded signal Sc1. The decoded image signal is decoded by the decoding circuit 40, and the decoded image signal is converted into the field image signal S r1 corresponding to the scanning line structure of the field screen by the reverse blocking circuit 51. Further, the field image signal S r1 is up-sampled in field units by the field unit up-sampler 61, and the up-sampled image signal S u1 is output from the present image decoding device 2 10b.

FIG. 18 (b) is a block diagram showing a configuration of an image decoding apparatus that upsembles in frame units. In FIG. 18 (b), reference numeral 220b denotes an image decoding device that decodes the image encoded signal encoded by the image encoding device 220a, and this image decoding device 2 20 b is an image decoding circuit 40 that decodes the image encoded signal S c 2 transmitted from the image encoding device 220 a, and inversely blocks the image decoded signal S c 2 That is, a reverse-blocking circuit 52 that converts the frame image signal Sr2 into a frame image signal Sr2 corresponding to the scanning line structure of the frame screen, and a frame-unit upsampler 6 that upsamples the frame image signal Sr2 in field units 2 to output the up-sampled signal S u 2. When the image decoding device 220 b having such a configuration receives the image coded signal S c 2 coded by the image coding device 220 a, the image coded signal S c 2 becomes The image is decoded by the decoding circuit 40, and the decoded image signal is converted into a frame image signal S r2 corresponding to the scanning line structure of the frame screen by the deblocking circuit 52. Further, the frame image signal Sr2 is upsampled in frame units by the frame unit upsampler 62, and the upsampled image signal Su2 is output from the present image decoding device 220b. Is done.

However, in the conventional image encoding apparatus, when encoding the input image signal S 1 n, the down-sampling processing of the input image signal S in is performed for one field or one frame of the input image signal S 1 n. Since one of them is performed as a unit, there is a problem that the encoding process involving down-sampling may not be properly performed on the interlaced image signal.

Hereinafter, this problem will be described in detail. T / JP98 / 02835

8 Fig. 19 shows the display image obtained from the interlaced image signal. Fig. 19 (a) shows the moving arc image, that is, the field, based on the interlaced image signal. An image of a circular arc with different positions between them is displayed as a one-frame image. Fig. 19 (d) shows a still image, that is, a thin 3D image with the same position between fields, based on the interlaced image signal. The straight line image of the book is shown as a one-frame image. In addition, FIGS. 19 (b) and 19 (c) show the arc images with the above-mentioned) based on the interlaced image signal, respectively, before and after the adjoining arc constituting one frame. Fig. 19 (e) and Fig. 19 (f) show an image of the above three lines of stationary thin lines based on the interlaced image signal. The images displayed before and after the adjacent field are shown as images.

FIG. 20 shows a display image obtained from a down-sampled signal obtained by down-sampling the interlaced image signal in units of one frame, and FIG. 20 (a) shows a display image based on the down-sampled signal. FIG. 20 (b) and FIG. 20 (c) show the moving arc image as one frame image, respectively, based on the down-sampled signal. Is shown as an image of each field before and after composing one frame.

Fig. 20 (d) shows the above three still thin straight line images as one frame image based on the downsampled signal. Figs. 20 (e) and 20 (f) The figure shows the stationary linear image displayed as an image of each field before and after forming one frame based on the downsampled signal.

Here, a comparison between the image obtained from the interlaced image signal (Fig. 19) and the image obtained from the signal obtained by down-sampling the interlaced image signal in frame units (Fig. 20) shows that a still image is obtained. 20 (d)-(As can be seen from the figure, downsampling of the input image signal Sin in units of frames hardly deteriorates the surface quality, but for images with motion, As can be seen from Fig. 20 (b) and Fig. 20 (c), the image of each field that constitutes one frame has two arcs at different positions. Frame by frame when encoding Even if the signal downsampled in step 1 is upsampled in units of frames during decoding, the field image obtained from this upsampled signal is one in which two arcs at different positions have appeared and the image quality has deteriorated greatly. Becomes This is because down-sampling the interlaced image signal on a frame-by-frame basis causes image information to be mixed in each field, which is an interlaced image signal at a different time. FIG. 21 shows how the two pieces of image information are mixed. In FIG. 21, the images shown in FIGS. 19 (b) and 19 (c) are displayed on the first and second field screens FI 1 and FI 2 constituting the one-frame screen FL. ing. In the figure, the white circles indicate the pixel values of the pixels forming the first field screen obtained from the interlaced image signal, and the white triangles indicate the second field obtained from the interlaced image signal. This is a pixel value of a pixel constituting the screen.

In such a process of down-sampling the interlaced image signal in frame units, the image signal G1 corresponding to the first field screen FI1 in the interlaced image signal and the second field screen F1 in the interlaced image signal are used. The image signal G corresponding to 2 is combined with the image signal G 2 to generate an image signal GO corresponding to the one-frame screen FL, and the image signal GO is down-sampled. At the time of this downsampling, for example, a process is performed in which the pixel values of four adjacent pixels are averaged and replaced with the pixel value of one pixel (the pixel indicated by a white square in the figure). In this case, the pixel values of the pixels of the image signal DG obtained by the down-sampler are information of both the pixel values of the pixels of the first field screen FI1 and the pixel values of the pixels of the second field screen FI2. Will be included.

Therefore, the up-sampling of the image signal DG obtained by the down-sampling is performed, and the up-sampled image signal corresponding to the 1-frame screen having the same resolution as the image signal G 0 corresponding to the 1-frame screen before the down-sampling is performed. Even if the UG is generated, both the image signal UG and the image signals UG 1 and UG 2 corresponding to each field obtained from the image signal UG are displayed on both the field screens FI 1 and FI 2 before down-sampling. It contains information on the image signals G1 and G2.

On the other hand, FIG. 22 shows a display image obtained from a down-sampled signal obtained by down-sampling the interlaced image signal in units of one field. The figure shows the arc image as a one-frame image based on the down-sampled signal corresponding to the moving arc image. FIGS. 22 (b) and 22 (c) show the respective images. The arc image is displayed as an image of each field constituting one frame based on the downsampled signal.

FIG. 22 (d) shows the straight-line image displayed as one frame image based on the down-sampled signals corresponding to the three still thin linear images. FIG. 22 (0) shows the straight line image displayed as an image of each field constituting one frame based on the down-sampled signal.

Here, comparing the image obtained from the interlaced image signal (Fig. 19) with the image obtained from the signal obtained by down-sampling the interlaced image signal in field units (Fig. 22), As shown in Figs. 22 (a) to (c), for a certain image, there is almost no deterioration in image quality even when down-sampling is performed on a field-by-field basis. B) As shown in the figure, the straight line image is lost by downsampling in field units. For this reason, even if the input image signal Sin downsampled at the time of encoding is upsampled at the time of decoding, the linear shape remains lost in the image obtained from the oversampled signal, which causes a large deterioration in image quality. It will be. This is because down-sampling the interlaced image signal on a field-by-field basis reduces the number of pixels in the signal obtained by the down-sampling process, so that there is almost no pixel information about fine shapes. .

FIG. 23 shows how the image information on the fine shape disappears. In FIG. 23, the images shown in FIGS. 19 (e) and 19 (f) are displayed on the first and second field screens FI 1 and FI 2 constituting the one-frame screen FL. Have been. Here, only one thin straight line is shown. In the figure, white circles indicate the pixel values of the pixels constituting the first field screen FI1 obtained from the interface image signal, and white triangles indicate Is a pixel value of a pixel constituting the second field screen FI2 obtained from the interlaced image signal.

Processing for downsampling such interlaced image signals in field units In the interlaced image signal, the image signal G1 corresponding to the first field screen FI1 in the interlaced image signal is downsampled to obtain a downsampled signal DG1, and the image corresponding to the second field screen FI2 in the interlaced image signal is obtained. Downsample the signal G2 to obtain the downsampled signal DG2. At the time of this down-sampling, for example, the pixel values of a plurality of adjacent pixels are averaged to one pixel for the image signals G 1 and G 2 of each field (in the figure, a black circle and a black triangle respectively). The pixel value of the pixel indicated by the mark is replaced. The figure shows the case where the pixel values of four adjacent pixels are replaced with the pixel values of one pixel, but in actuality, the pixel values of many adjacent pixels and many pixels are averaged, for example, the pixel value of one pixel Is performed. In this case, in the image signals DG 1 and DG 2 obtained by the down-sampling, the information in the image signals 0 1 and G 2 of the first and second field screens FI 1 and? Become. Therefore, the image signals DG 1 and DG 2 obtained by the down-sampling are up-sampled to obtain the image signals of the first and second field screens FI 1 and FI 2 before the down-sampling. Even if the image signals UG 1 and UG 2 corresponding to the first and second field screens having the same resolution (that is, the number of pixels) are equal to G 1 and G 2, the information lost due to the down-sampling is not restored. For a complicated shape, the image quality is greatly deteriorated.

As described above, downsampling in units of frames in the encoding process of the input image signal S in causes degradation in image quality of a moving image, and downsampling in units of fields causes degradation in vertical resolution of a still image. Thus, it was impossible to perform an encoding process involving downsampling on both a moving image and a still image without deteriorating the image quality.

For the same reason as for the downsample in the encoding process, the upsample in the decoding process is similar to the downsample in the encoding process. In such a case, the upsampling in units of frames would cause image quality degradation, and it would not be possible to perform decoding processing with upsampling on both a moving image and a still image without causing image quality degradation. It was possible.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. To obtain an image encoding method and an image encoding device capable of performing an efficient encoding process without deteriorating the image quality due to the image processing, and a data storage medium storing a program for implementing the encoding process. The purpose is to:

Further, the present invention provides an image decoding method and an image decoding device capable of performing efficient encoding processing without deterioration of image quality due to up-sampling, and a program for realizing the decoding processing. The purpose is to obtain the stored data storage medium. -Disclosure of invention

An image encoding method according to the present invention (Claim 1) is a surface image encoding method for performing an encoding process with down samples on an image signal, based on the image signal. It is determined whether the downsampling for the image signal should be performed on a field basis or on a frame basis. According to the determination result, the image signal is downsampled on a field basis or on a frame basis. The down-sampled image signal is encoded in display block units of a predetermined size that divides the display screen, and the image encoded signal obtained by encoding in the display block unit and the down sampled are frame unit and field unit. A mode coded signal obtained by coding a mode signal indicating which of the units is used is output. According to the image coding method having such a configuration, it is determined based on the image signal whether down-sample processing on the image signal should be performed on a field basis or on a frame basis. Accordingly, the above-mentioned image signal is downsampled in field units or frame units, so that when encoding a still image or a moving image with motion, a downsampler suitable for each image signal is encoded. Since the sample processing is performed, it is possible to prevent the deterioration of the image quality due to the download sampling processing for both the still image and the moving image.

According to a second aspect of the present invention, in the image encoding method according to the first aspect, there is provided an image decoding method for decoding an encoded image encoded signal and a mode encoded signal. A method for decoding the image encoded signal in units of the display blocks to generate an image decoded signal, and decoding the mode encoded signal to generate a decoded mode signal. When the decoding mode signal indicates that the down-sampling is performed on a frame basis, an image signal corresponding to a frame is generated from the image decoded signal, and the image signal is generated on a frame basis. When the demodulation mode signal indicates that the downsampling was performed in units of fields, an image signal corresponding to a field is generated from the image decoding signal. Then, the image signal is up-sampled and output in field units.

According to the image decoding method having such a configuration, the mode-encoded signal in the image encoding method according to claim 1 is decoded, and the down-sample processing in the image encoding method is performed in units of fields. When a decoding mode signal indicating which unit of the frame unit is used is obtained, and when the image coded signal coded by the above image coding method is decoded, the decoding mode signal is down-framed. When the sample processing is indicated, an image signal corresponding to a frame is formed from the decoded block image signal, and up-sampled in frame units. When the decoding mode signal indicates down-sample processing in field units, decoding is performed. An image signal corresponding to a field is configured from the block image signal that has been converted, and up-sampling is performed in field units. Therefore, when decoding an encoded image signal corresponding to a still image and a moving image, an up-sampling process suitable for each is performed, thereby deteriorating the image quality of both the still image and the moving image. The decoding process involving the up sample of the image coded signal can be performed without inducing.

The present invention (Claim 3) is an image encoding method for encoding a broken image signal obtained by blocking an image signal so as to correspond to each display block of a predetermined size for dividing a display screen. , Above block]! It is determined whether the image signal is to be coded in field units or frame units. If the image signal is to be coded in field units, the block image signal is down-sampled in field units and the down-sampled signal is When encoding is performed on a field-by-field basis to generate an image-encoded signal, and when encoding should be performed on a frame-by-frame basis, the blocked image signal is down-sampled on a frame-by-frame basis and the down-sampled signal is encoded on a frame-by-frame basis to encode an image. A coded signal is generated, and the image coded signal and a model indicating whether the downsample is performed in a frame unit or a field unit. And outputs a mode-coded signal obtained by coding a mode signal.

According to the image encoding method having such a configuration, when encoding an input image signal into a block image processing in which a display screen is divided into display blocks each having a predetermined size, the block image signal is filtered. It is determined whether encoding should be performed in field units or frame units. According to the determination result, the block image signal is down-sampled in field units or frame units, and the down-sampled signal is converted in field units. Alternatively, since an image-encoded signal is generated by encoding each frame, a down-sampling process suitable for each image signal is performed when encoding both a still image and a moving image. This prevents image degradation due to downsampling for both still images and moving images. Can be

The present invention (Claim 4) is an image decoding method for decoding an encoded image coded signal and a mode coded signal according to the image coding method according to Claim 3. And decoding the mode-encoded signal to generate a decoding mode signal. When the decoding mode signal indicates that the down-sampling has been performed in field units, A signal is decoded in units of fields, and the decoded image signal is output by assembling in units of fields, and when the mode signal indicates that the downsampling is performed in units of frames, The coded image signal is decoded in frame units, and the decoded signal is upsampled in frame units and output.

According to the image decoding method having such a configuration, the mode-encoded signal in the image encoding method according to claim 3 is decoded, and the downsampling process in the image encoding method is filtered. A decoding mode signal indicating whether the decoding is performed in a frame unit or a frame unit, and when decoding the image coded signal coded by the image coding method, an image is generated according to the decoding mode signal. Since the coded signal is decoded in units of fields or frames, and upsampled in units of finolades or frames, an image coded signal is generated, so that coding corresponding to still images and moving images is performed. When decoding an image signal, upsampling processing that is appropriate for each is performed. Also, it is possible to perform decoding processing involving up-sampling of an image coded signal without deteriorating image quality.

The present invention (claim 5) performs an encoding process with motion compensation on a block image signal obtained by dividing an image signal for each display block of a predetermined size for dividing a display screen. An image coding method for generating an image coded signal, wherein when the magnitude of a motion vector obtained from the image signal is equal to or larger than a predetermined value, the sampled image signal is downsampled in field units. On the other hand, when the size of the motion vector obtained from the image signal is smaller than a predetermined value, the block image signal is down-sampled in frame units, and the down-sampled block image signal is encoded. And outputting an image coded signal obtained by coding the block image signal and a motion vector coded signal obtained by coding the motion vector. A.

According to the image encoding method having such a configuration, an input image signal is subjected to motion compensation encoding on a block image signal obtained by dividing a display screen into display blocks each having a predetermined size. When generating a segmented signal, the blocked image signal is down-sampled in field units or frame units according to the size of the motion vector obtained from the image signal, and the blocked image signal is motion compensated. Since encoding is performed, downsampling processing suitable for each image signal is performed when encoding both still images and moving images with motion, and the still image and the moving image In any case, image quality degradation due to downsampling can be prevented, and switching of downsampling can be performed in a motion vector. Are performed in Zui, it is possible to save the code mold Tsu City of signal indicating the switching of downsampling processing.

The present invention (Claim 6) is an image decoding method according to Claim 5, wherein the generated image coded signal is decoded. The coded signal is decoded to generate an image decoding signal, and the motion vector coded signal is decoded to generate a decoded motion vector signal, and the size of the decoded motion vector is predetermined. If the value is equal to or greater than the value, the decoded image signal is upsampled and output in field units, while the size of the decoded motion vector is smaller than a predetermined value. In the case of, the decoded image signal is up-sampled and output in frame units.

According to the image decoding method having such a configuration, the motion vector coded signal in the image coding method according to claim 5 is decoded to generate a decoded motion vector signal, In accordance with the size of the decoding motion vector, the decoded image signal is upsampled in field units or frame units and output to generate an image decoded signal. When decoding an image-encoded signal corresponding to a moving image, upsampling processing suitable for each is performed, so that the image quality is not degraded for both the still image and the moving image without deteriorating the image quality. The decoding process involving the amplifier samples of the encoded signal can be performed, and the downsampling process is switched based on the motion vector. It is possible to save the coded bits of the signal indicating the example.

The present invention (claim 7) is an image coding apparatus for coding an image signal, comprising: field down-sampler for down-sampling the image signal in field units; Frame down-sampling means for down-sampling in units; and determining, based on the image signal, whether to down-sample the image signal in units of fields or in units of frames. Determination means for outputting a mode signal; a selection switch for selecting and outputting one of the output of the field downsampling means and the output of the frame downsampling means in accordance with the mode signal; and the selection switch. The output signal of the switch is divided into blocks to correspond to each display block of a predetermined size that divides the display screen. Block generating means for outputting an image signal; coding means for coding the block image signal in units of display blocks to generate a picture coded signal; and coding a mode coded signal by coding the mode signal And mode encoding means for generating the image encoding signal and outputting the image encoded signal and the mode encoded signal as output signals.

According to the image encoding apparatus having such a configuration, the image encoding apparatus includes: a field downsampler that downsamples an input image signal in units of fields; and a frame downsampler that downsamples the input image signal in units of frames. Input image Since the output of one of the two down-sampling means is coded based on the determination result of whether the down-sampling process on the signal should be performed on a field basis or on a frame basis, the motion of a still image can be improved. Downsampling processing suitable for each video signal is also performed for a certain moving picture, and for both still pictures and moving pictures, image quality degradation due to encoding processing involving downsampling is prevented. Can be.

The present invention (claim 8) provides the image decoding method according to claim 1, wherein the encoded image encoded signal and the mode encoded signal are decoded. A decoding device for decoding the image-encoded signal for each display block to generate an image-encoded signal; and a decoding module for decoding the mode-encoded signal to decode the image-encoded signal.

Mode decoding means for generating a code signal and a decoded image signal corresponding to the display block, which is an output of the decoding means, are converted into an image signal corresponding to a frame or a field. Deblocking means, frame up sampling means for up-sampling the image signal integrated by the deblocking means on a frame basis, and image signals integrated by the deblocking means on a field basis. Field up-sampling means for sampling, and a selection switch for selecting one of the outputs of the up-sampling means in accordance with the decoding mode signal, and outputting the output of the selection switch to the image coded signal. Is output as a decoded image signal.

According to the image decoding device having such a configuration, a decoded image signal corresponding to a display block of a predetermined size that divides a display screen is integrated and converted into an image signal corresponding to a frame screen or a field screen. De-blocking means, frame-up sampling means for up-sampling the output of the de-blocking means in frame units, and field-up samples for up-sampling the output of the de-blocking means in field units Means for selecting one of the outputs of the up-sampling means according to a decoding mode signal obtained by decoding the mode-encoded signal in the image encoding method according to claim 1. Therefore, when decoding the coded image signals corresponding to the still image and the moving image, upsampling processing suitable for each is performed. As a result, image quality of both still images and moving images may be degraded. In addition, it is possible to perform a decoding process involving an up sample of the image coded signal. The present invention (claim 9) is an image coding apparatus for coding a block image signal obtained by blocking an image signal so as to correspond to each display block of a predetermined size that divides a display screen. A determination unit that determines whether the block image signal should be encoded in a field unit or a frame unit, and outputs a mode signal corresponding to the determination result; A field down-sampler for down-sampling in units of unit, a field encoder for coding the output of the field-based down-sampler in units of field, and a frame down-sampler for down-sampling the block image signal in frame units A pull unit, and a frame for encoding the output of the frame unit down sampling unit in frame units. A coding switch, a selection switch for selecting and outputting one of the outputs of the coding means in accordance with the mode signal, and a mode coding signal generated by coding the mode signal from the determination means. A mode encoding means for outputting a down-sampled encoded signal from the selection switch and a mode encoded signal from the mode encoding means.

According to the image encoding apparatus having such a configuration, a block image signal obtained by dividing an input image signal into display blocks of a predetermined size for dividing a display screen is encoded in any of a field unit and a frame unit. Determining means for determining whether the power should be increased or not, down-sampling the blocked image signal in field units or frame units in accordance with the determination means, and encoding the down-sampled signal in field units or frame units In order to generate a coded image signal, a down-sampling process suitable for each image signal is performed at the time of coding both a still image and a moving image having motion. For both images and moving images, it is possible to prevent image quality deterioration due to encoding processing involving downsampling. Wear.

The present invention (Claim 10) is an image decoding apparatus for decoding an encoded image coded signal and a mode coded signal in the image coding method according to Claim 3. A mode decoding means for decoding the mode coded signal and outputting a decoded mode signal, and a mode decoding means for decoding the image coded signal in field units. Field decoding means; field up-sampling means for up-sampling the output of the field decoding means in field units; frame decoding means for decoding the image signal in frame units; and frame decoding. Frame up-sampling means for up-sampling the output of the means in frame units; and a selection switch for selecting and outputting one of the outputs of the up-sampling means in accordance with the decoding mode signal. And outputs the output of the switch as an image decoded signal obtained by decoding the image encoded signal. -According to the image decoding apparatus having such a configuration, a mode decoding that decodes a mode-coded signal in the image coding method according to claim 3 and outputs a decoded mode signal. Decoding means for decoding an image coded signal in field units or frame units in accordance with the decoding mode signal, and further up-samples in field units or frame units to generate a decoded image signal Therefore, when decoding an encoded image signal corresponding to a still image and a moving image, an appropriate upsampling process is performed for each of the images, thereby improving the image quality of both the still image and the moving image. It is possible to perform a decoding process involving upsampling of an image coded signal without deteriorating image quality.

The present invention (ffl calculation range 1st section) is to perform motion compensation on an image signal with a block-blocked image signal corresponding to each display block of a predetermined size for dividing a front / bottom screen. An image encoding apparatus that performs an associated encoding process and outputs an image encoded signal, and determines whether a magnitude of a motion vector obtained from the blocked image signal is equal to or greater than a predetermined value, Determining means for outputting a mode signal corresponding to the determination result; motion vector coding means for coding the motion vector to generate a motion vector coded signal; Field downsampling means for downsampling the signal in field units; frame downsampling means for downsampling the blocked image signal in frame units; A selection switch for selecting and outputting one of the outputs of the sampling means, and an encoding means for encoding the output of the selection switch to generate an image-encoded signal. And outputs the encoded motion vector encoded signal and the image encoded signal encoded by the encoding means. According to the image coding apparatus having such a configuration, the magnitude of a moving vector obtained from a block image signal obtained by dividing an input image signal into display blocks each having a predetermined size for dividing a display screen has a predetermined value. Determining means for determining whether or not the above is satisfied, downsampling the blocked image signal in field units or frame units in accordance with the size of the motion vector, and converting the blocked image signal into a motion compensation code Therefore, when encoding still images and moving images with motion, downsampling processing suitable for each image signal is performed, and both still images and moving images are processed. In any case, image quality degradation due to downsampling can be prevented, and switching of downsampling is performed based on the motion vector. Therefore, the coding bit of the signal indicating the switching of the downsampling processing can be saved.

The present invention (Claim 12) is the image encoding method according to Claim 5, wherein the image decoding method comprises the steps of: decoding an encoded image coded signal and a motion vector coded signal. An apparatus, comprising: decoding means for decoding the image coded signal to generate an image decoded signal; and a motion vector for decoding the motion vector coded signal to generate a decoded motion vector. To determine whether the magnitude of the decoding motion vector is greater than or equal to a predetermined value, and to output a mode signal corresponding to the determination result. Field-up sampling means for up-sampling the output in field units, frame up-sampling means for up-sampling the output of the above-mentioned decoding means in frame units, and both of the above-mentioned amplifiers according to the mode signal A selection switch for selecting and outputting one output of the sample means, and outputting the output of the selection switch as a decoded image signal.

According to the image decoding device having such a configuration, the image decoding method further includes: a motion vector decoding unit that decodes a motion vector encoded signal in the image encoding method according to claim 5. In accordance with the size of the motion vector, the decoded image signal is upsampled in field units or frame units and output to generate a decoded image signal. When decoding an encoded image signal, upsampling processing suitable for each of them is performed, thereby enabling image encoding without deteriorating image quality for both still images and moving images. Since decoding processing involving up-sampling of a signal can be performed, and switching of down-sampling processing is performed based on a motion vector, encoding bits of a signal indicating switching of down-sampling processing can be saved. be able to.

The present invention (claim 13) is a data storage medium storing a program for performing the image encoding method according to claim 1 by a computer. A process of determining, based on the image signal, a force to perform downsampling on the image signal on a field basis or on a frame basis; and, depending on the determination result, down-convert the image signal on a field basis or on a frame basis. A sampling process, a process of encoding the down-sampled image signal in display block units of a predetermined size for dividing a display screen, and an image encoded signal obtained by encoding in the display block unit. A mode indicating whether the downsampling was performed in frame units or field units ¾ - a process of outputting a mode encoded signal obtained by encoding, are those to I line.

According to the data storage medium having such a configuration, based on the image signal, a process of determining whether to perform the down-sampling process on the image signal on a field basis or on a frame basis. A program for causing a computer to perform the process of down-sampling the image signal in units of fields or frames is stored. By loading the program into the computer, the coding of a still image and a moving image having motion is performed. At this time, down-sample processing suitable for each image signal is performed, and for both still images and moving images, encoding processing that can prevent image quality deterioration due to down-sampling is implemented by computer. Can be.

The present invention (claim 14) is a data storage medium storing a program for performing the image decoding method according to claim 2 by a computer, wherein the program is stored in a computer. A process of generating a decoded image signal by decoding the coded image signal in units of the display blocks; a process of generating a mode signal by decoding the coded mode signal; and When it indicates that the processing has been performed on a frame basis, the frame Generating an image signal corresponding to the frame, up-sampling and outputting the image signal in frame units, and when the mode signal indicates that down-sampling is performed in frame units, A process of generating an image signal corresponding to a field from the decoded signal, up-sampling the image signal in units of a field, and outputting the result is performed.

According to the data storage medium having such a configuration, the mode-encoded signal in the image encoding method according to claim 1 is converted to i-th order, and the down-sampling processing in the image encoding method is performed. A process for obtaining a decoding mode signal indicating whether the processing is performed in a field unit or a frame unit, and when the decoding mode signal indicates a down sampling process in a frame unit, a frame corresponding to a frame is obtained from the decoded blocked image signal. If the image signal is composed and up-sampled in frame units, and the decoding mode signal indicates down-sampling processing in field units, the image signal corresponding to the field is decoded from the decoded blocked image signal. A program that allows the computer to perform the process of configuring and up-sampling in units of fields is stored. By loading this into a computer, up-sampling processing suitable for each of the coded signals corresponding to the still image and the moving image is performed. Also, the decoding process involving the upsampling of the image coded signal can be realized by the computer without deteriorating the image quality.

The present invention (claim 15) is a data storage medium storing a program for performing the image encoding method according to claim 3 by a computer. A process of determining whether to encode a block image signal in units of fields or frames, and in units of shift.If encoding is to be performed in the above field units, the above block image signal is downsampled in units of fields. When the down-sampled signal is to be encoded in units of fields and to be encoded in units of frames, a process of down-sampling the blocked image signal in units of frames and encoding the down-sampled signals in units of frames. , And an image encoded signal obtained by encoding the blocked image signal; Line in any of the units of the emissions sample frame-by-frame basis and field-by-field basis A process of outputting a mode-coded signal obtained by coding a mode signal indicating whether the mode has been performed is performed.

According to the data storage medium having such a configuration, when the input image signal is encoded with the block image signal divided for each display block of a predetermined size for dividing the display screen, the block image signal is divided into fields or A process of determining in which frame unit coding should be performed, and, in accordance with the determination result, down-sampling the blocked image signal in field units or frame units, and field the down-sampled signal. A program for causing a computer to perform a process of generating an image-encoded signal by encoding in units or frames is stored. By loading the program into the computer, any of a still image and a moving image is stored. Encoding processing that can prevent image degradation due to downsampling It can be realized by a computer.

The present invention (claim 16) is a data storage medium storing a program for performing the image decoding method according to claim 4 by a computer. A process of decoding the mode coded signal to generate a decoding mode signal; and, when the decoding mode signal indicates that the downsampling has been performed on a field basis, the image coding When the signal is decoded in units of fields, the decoded image signal is sampled in units of fields and output, and the decoding mode signal indicates that the downsampling is performed in units of frames. And decoding the coded image signal in frame units, and up-sampling and outputting the decoded image signal in frame units. Things.

According to the data storage medium having such a configuration, the mode-encoded signal in the image encoding method according to claim 3 is decoded, and the down-sample processing in the image encoding method is performed in field units and frame units. A process for obtaining a decoding mode signal indicating which unit has been performed; and, when decoding an image-encoded signal encoded by the above-described image encoding method, image encoding is performed according to the decoding mode signal. The signal is decoded in units of finale or frame, and upsampled in units of fields or frames to generate a decoded image signal. Since the program to be executed by the computer is stored, the above program is loaded into the computer, so that when decoding the image coded signal corresponding to the still image and the moving image, the appropriate up-sampling is performed. The processing is performed, whereby the decoding processing involving the amplifier samples of the image-encoded signal can be realized by the computer without deteriorating the image quality of both the still image and the moving image.

The present invention (claim 17) is a data storage medium storing a program for performing the image encoding method according to claim 5 by a computer, wherein the program is stored in a computer. When the size of the motion vector obtained from the image signal is equal to or larger than a predetermined value, the block image signal is down-sampled in field units, while the size of the motion vector obtained from the image signal is a predetermined value. If the value is less than 1, a process of down-sampling the blocked image signal in frame units, a process of encoding the down-sampled blocked image signal, and a self-image obtained by encoding the blocked image signal Processing for outputting an encoded signal and a motion vector encoded signal obtained by encoding the motion vector. Things.

According to the data storage medium having such a configuration, an input image signal is subjected to motion compensation coding processing on a block image signal divided for each display block of a predetermined size which divides a display screen, and an image is formed. When generating an encoded signal, the block image signal is downsampled in field units or frame units according to the size of the motion vector obtained from the image signal, and the block image signal is motion compensated. Since a program for causing a computer to perform the encoding process is stored, by loading the program into the computer, it is possible to prevent the deterioration of image quality due to the down-sampling process for both still images and moving images. Encoding that can switch the down-sampling process Management it is possible to achieve by Konbyu Ichita.

The present invention (claim 18) is a data storage medium storing a program for performing the image decoding method according to claim 6 by a computer. Decodes an image coded signal and decodes the image. A process of generating an encoded signal and decoding the motion vector coded signal to generate a decoded motion vector signal; and, when the magnitude of the decoded motion vector is equal to or greater than a predetermined value, A process of up-sampling the decoded image signal in field units and outputting it, while upsampling the decoded image signal in frame units and outputting it when the size of the decoded motion vector is smaller than a predetermined value. It is what is done.

According to the data storage medium having such a configuration, a process of decoding the motion vector coded signal in the image coding method according to claim 5 to generate a decoded motion vector signal, and According to the size of the decoding motion vector, the decoded image signal is up-sampled and output in field units or frame units, and the computer performs a process of generating an image decoded signal. Since the program is stored, the decoding process that does not cause deterioration of the image quality of both the still image and the moving image and that can save the coded bits of the signal indicating the switching of the down-sampling process can be performed. It can be realized by a computer. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram for explaining a configuration of an image encoding device according to Embodiment 1 of the present invention.

FIG. 2 is a flowchart showing the operation of the image encoding device according to the first embodiment.

FIG. 3 is a block diagram for explaining a configuration of an image decoding device according to Embodiment 2 of the present invention.

FIG. 4 is a flowchart showing the operation of the image decoding apparatus according to the second embodiment.

FIG. 5 is a block diagram for explaining a configuration of an image encoding device according to Embodiment 3 of the present invention.

FIG. 6 is a diagram illustrating, by a flowchart, an operation of the image encoding device according to the third embodiment.

FIG. 7 is a diagram for explaining a configuration of an image decoding apparatus according to Embodiment 4 of the present invention. It is a block diagram of.

FIG. 8 is a diagram showing the operation of the image decoding apparatus according to the fourth embodiment in a single chart.

FIG. 3 is a block diagram for explaining a configuration of an image encoding device according to Embodiment 5 of the present invention.

FIG. 10 is a diagram showing, by a flowchart, the operation of the image coding apparatus according to the fifth embodiment.

FIG. 11 is a block diagram for explaining a configuration of an image decoding apparatus according to Embodiment 6 of the present invention.

FIG. 12 is a diagram showing, by a flowchart, the operation of the image decoding apparatus according to the sixth embodiment.

FIG. 13 is a diagram showing a data storage medium for storing a program for realizing the image encoding process or the image decoding process of each of the above-described embodiments by a computer system.

Fig. 14 is a diagram conceptually showing the encoding and decoding processing with downsampling and upsampling.

FIG. 15 is an explanatory diagram of a conventional image encoding device, and shows a circuit configuration for performing an encoding process with down-sampling on a blocked input image signal. FIG. 16 is an explanatory diagram of a conventional image decoding apparatus, and shows a circuit configuration for immediately performing a decoding process involving up-sampling on a decoded image signal.

FIG. 17 is an explanatory diagram of a conventional image encoding device, and shows a circuit configuration for performing block processing and encoding processing after down-sampling an input image signal. FIG. 18 is an explanatory diagram of a conventional image decoding device, and shows a circuit configuration for performing an up-sampling process after performing a deblocking process on a decoded image signal. FIG. 19 is a diagram showing a state in which interlaced image signals corresponding to a still image and a moving image are displayed on one frame screen and on each frame screen constituting the one frame.

FIG. 20 shows an image signal in which an interlaced image signal corresponding to a still image and a moving image is obtained as one frame image and one frame image. FIG. 9 is a diagram showing images of respective frames constituting a program.

FIG. 21 is a diagram showing a state in which image information corresponding to each field is mixed by the down-sampling processing in units of frames.

FIG. 22 shows an image signal obtained by down-sampling an interlaced image signal corresponding to a still image and a moving image on a field-by-field basis as a one-frame image and an image of each frame constituting the one frame. _U

FIG. 23 is a diagram showing a state in which image information on a fine shape is lost due to a downsemble in a field unit. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 13. Embodiment 1

FIG. 1 is a block diagram for explaining an image coding apparatus according to Embodiment 1 of the present invention. In the figure, the same reference numerals as those in FIG. 17 denote the same components as those of the conventional image encoding device 210a, and 110a denotes the encoding of the input image signal S in with down-sampling. 1 is an image encoding device according to a first embodiment that performs processing.

The image encoding device 110a receives the input image signal S1n, and determines whether to perform the downsampling on a field basis or on a frame basis based on the input image signal Sin, A frame field determination circuit 1 that outputs a mode signal S m corresponding to the determination result, and a mode encoding circuit 2 that encodes the mode signal S m and outputs a mode encoded signal S mc, Further, it has a field unit and frame unit downsampler 1] a, 12a having the same configuration as that of the conventional image coding devices 210a, 220a.

In the image encoding device 110a of the first embodiment, an input image signal Sin is provided at a stage preceding the both down-samplers 1la and 12a based on the mode signal Sm. An input selection switch 3 for supplying to one of the down-samplers is provided, and the downstream of both down-samplers 1 la and 12 a is provided at the subsequent stage based on the mode signal Sm. An output selection switch 4 for selecting and outputting one of the outputs S d 1 and S d 2 is provided. Also, in this image encoding device 110a, The output of the output selection switch 4 is blocked by a blocking circuit 20 so as to correspond to a display block (block) of a predetermined size that divides the display screen. Is encoded. Next, the operation will be described.

FIG. 2 is a flowchart illustrating an encoding process performed by the image encoding device 110a.

First, when the input image signal 5 in is input to the image encoding device 110a (step S1), the frame / field determination circuit 1 performs the input based on the input image signal S in It is determined whether the image signal Sin should be downsampled on a field basis or on a frame basis. At this time, a mode signal Sm corresponding to the determination result is output (step S2). Here, as a specific method of the above determination, the pixel value of the corresponding pixel is compared between each field constituting one frame, and the difference between the pixel values of the corresponding pixel between the fields is equal to or less than a predetermined value. It depends on whether it is a force or not.

Then, according to the determination result, down-sampling processing is performed on the input image signal S in. That is, as a result of the above determination processing, if downsampling processing in frame units should be performed, the input selection switch 3 is set to the mode signal S m so that the input image signal Sin is supplied to the frame unit downsampler 11a. The input image signal S 1 _n is down-sampled in frame units by the down-sampler 11 a (step S 3). On the other hand, as a result of the above determination process, when down sampling processing in the field unit should be performed, the input selection switch 3 is set so that the input image signal S in is supplied to the field unit down sampling unit 12 a. Switching is performed based on the mode signal Sm, and the downsampler 12a downsamples the input image signal S1n in field units (step S4). Further, the mode signal, that is, an identification signal indicating in which unit of the frame or the field the down-sampling has been performed is coded and output as a mode coded signal Smc (step S5).

The input image signal subjected to the down-sampling process, that is, the output S d of the output selection switch 4 is blocked by the blocking circuit 20, that is, the display image The surface is divided into blocks each having a predetermined size (step S6), and the output Sb of the block circuit 20 is subjected to encoding processing in units of the above blocks by the image encoding circuit 30 for encoding. It is output as the image signal Sc (step S7).

In the image encoding device 110a according to the first embodiment having such a configuration, the frame / file that determines whether the downsampling process on the input image signal S1n should be performed on a frame basis or on a field basis. Since the input image signal S in is down-sampled according to the determination result, the input image signal corresponding to the still image is down-sampled in frame units. As a result, the spatial resolution in the vertical direction of the display screen can be prevented from deteriorating, and the input image signal S in corresponding to a moving image (moving image) is down-sampled in field units. As a result, the image quality in the time direction is prevented from being degraded, that is, the outline of a moving image is not blurred or the moving state becomes unnatural. Can be passed.

For example, specifically, when the input image signal represents a still image, down-sampling is performed on a frame-by-frame basis as shown in FIG. 20 (d), thereby obtaining a signal as shown in FIG. 22 (d). If the input image signal represents a moving image, the downsampling should be performed in field units as shown in Fig. 22 (b) and Fig. 22 (c). Thus, it is possible to prevent the images of the two field screens at different times from being combined as the image of the field screen at the same time, as shown in FIGS. 20 (b) and 20 (c).

Further, in the image encoding device 110a of the first embodiment, each processing after downsampling the input image signal S1n is performed in exactly the same manner as the conventional image encoding device 210a. Therefore, it is easy to ensure the upward compatibility with the conventional image encoding device.

Embodiment 2

FIG. 3 is a diagram for explaining an image decoding apparatus according to Embodiment 2 of the present invention. In the figure, the same reference numerals as those in FIG. 18 denote the same components as those of the conventional image decoding device 210 b, and 110 Ob denotes the image coding device 1 of the first embodiment shown in FIG. Decoding process with up-sampling for image coded signal Sc from 10a Is an image decoding device that performs the following.

The image decoding device 110b decodes the mode coded signal S me and decodes the down coded signal in a frame unit or a down unit in a field unit in the coding process. It has a mode decoder 6 for outputting the signal S me and an image decoding circuit 4 for decoding the image coded signal, and decodes by integrating the decoded image signal in block units which is the output S e. It has a deblocking circuit 50 that composes an image, and upsamplers 61b and 62b for each field and each frame. Here, the image decoding circuit 40, the inverse processing circuit 50, and the upsamplers 61b and 62b have the same configuration as those of the conventional image decoding devices 210b and 220b2. .

In the image decoding apparatus 110b according to the second embodiment, the output Sr of the inverse block circuit 50 is provided before the two up-samplers 6lb and 62b in the decoding mode signal Sm. e, an input selection switch 7 for supplying the signal to one of the knob samplers is provided, and based on the decoding mode signal Sme, the outputs Siil, Su of the two upsamplers are provided. An output selection switch 8 for selecting and outputting one of the two is provided.

Here, when the decoding mode signal Sme indicates downsampling in field units, the switches 7 and 8 select the input and output of the field unit upsampling device 41 and switch the decoding mode signal S If me indicates downsampling in frame units, the frame unit upsampler 62b is selected.

Next, the operation will be described.

FIG. 4 is a flowchart illustrating an image decoding process performed by the image decoding device 110b according to the second embodiment.

First, when the mode coded signal Smc and the coded image signal Sc are input to the image decoding device 110b, the mode coded signal Smc is decoded by the mode coding circuit 6. Then, a decoding mode signal Sme indicating whether the down-sampling processing in the image coding processing is down-sampling processing in fields or down-sampling in frames is output (step S10). Next, the image coded signal Sc is decoded by the image coding circuit 40 in units of blocks (step S11), and is divided into blocks by the inverse blocking circuit 50. The decoded image signals are integrated (step S12). Subsequently, up-sampling processing for the decoded image signal Sc is determined according to the decoding mode signal S me (step S 13). In other words, if the decoding mode signal indicates that the down-sampling processing at the time of encoding has been performed in frame units, then i: the output S r of the inverse blocking circuit is the frame unit up-sampler 6 2 b, the input selection switch 7 is switched based on the decoding mode signal Sme, and the inverse block output Sr is upsampled in frame units by the upsampler 62b. Step S14). On the other hand, when the decoding mode signal S me indicates that the down-sampling process at the time of encoding has been performed in units of fields, the inverse block output S r is used as the field unit up-sampler 6. The input selection switch 8 is switched based on the decoding mode signal Sme so as to be supplied to 1b, and the inverted block output Sr is up-sampled in field units by the sampler 61b. (Step S15).

At this time, the output selection switch 8 has selected one of the up-samplers 61b and 62b in accordance with the decoding mode signal Sme, and is up-sampled from the output selection switch 8. The deblocked output is output as a decoded image signal Su.

As described above, the image decoding apparatus 110b of the second embodiment decodes the decoding mode signal S mc to determine whether the up-sampling process for the image coded signal S c should be performed in frame units. A mode decoding circuit 6 is provided to generate a decoding mode signal Sme indicating whether the decoding should be performed in units, and the up-sampling processing of the deblocked output Sr is performed based on the decoding mode signal. For the deblocked output corresponding to a still image, the upsampling process is performed on a frame-by-frame basis, so that the spatial resolution in the vertical direction of the display screen can be prevented from deteriorating. For the inverse block output corresponding to the image (moving image), the up-sampling is performed on a field-by-field basis, and the image quality deteriorates in the time direction, that is, the ring of the moving image Prevent blurred or of the moving state is unnatural be able to.

Embodiment 3.

FIG. 5 is a block diagram for explaining an image coding apparatus according to Embodiment 3 of the present invention. In the figure, 120a is an encoding accompanied by down-sampling of a block image signal Sb obtained by blocking an image signal so as to correspond to a display block of a predetermined size for dividing a display screen. 15 is an image encoding device according to Embodiment 3 that performs processing.

The image coding apparatus 120a receives the block image signal Sb, and determines whether the image signal Sb should be downsampled in a frame unit or a field unit in the block unit. A frame / field discriminator 1a for judging and outputting a mode signal Sma according to the judgment result; and a mode for encoding the mode signal Sma and outputting a mode encoded signal Smac. Code encoding circuit 2a.

Further, the image encoding device 120a includes a field unit downsampler 31a for downsampling the blocked image signal Sb in a field unit, and a downsampled output Sd1 in the field. A field unit encoder 34 that encodes in units, a frame downsampler 32 a that downsamples the blocked image signal Sb in frame units, and a downsampled output Sd2 in frame. And a frame unit encoder 35 for encoding in units.

In the image encoding apparatus 120a, an input selection switch 3a is provided before the down-samplers 31a and 32a, and an output selection switch 4a is provided after the down-samplers. The input selection switch 3a supplies the blocked image signal Sb to one of the f * j downsamplers according to the mode signal Sma, and the output selection switch The switch 4a selects one of the outputs S c1 and S c2 of the both down-samplers according to the mode signal S ma and outputs the selected output as an image coded signal S c.

In other words, if the mode signal Sma indicates that the block image signal Sb should be subjected to the field unit encoding process, the input selection switch 3a is connected to the field unit downsampler 31a. Input to output select switch 4a Selects the output of the field unit encoder 34, and if the mode signal Sma indicates that the block image signal Sb should be subjected to frame unit encoding processing, the input selection switch The reference numeral 3a selects the input of the frame unit downsampler 32a, and the output selection switch 4a selects the output of the frame unit encoder 35.

Next, the operation will be described.

FIG. 6 shows an encoding process by the image encoding device 120a by a flowchart.

First, when the blocked image signal Sb is input to the image encoding device 120a (step S20), the frame Z field determination circuit 1a outputs the input image signal Sb It is determined whether the blocked image signal Sb should be downsampled in field units or should be downsampled in frame units based on the above, and a mode signal Sma corresponding to the determination result is output at this time. (Step S21). Then, according to the determination result, the down-sample processing and the encoding processing are performed on the block image signal Sb. That is, as a result of the above-described determination processing, when the down-sampling processing per frame should not be performed, the input selection switch 3a is set so that the blocked image signal Sb is supplied to the down-sampler 31a per field. Switching is performed based on the mode signal S ma, the block image signal S b is down-sampled in field units by the down-sampler 31 a (step S 22), and further, the field unit encoder 34 The down-sampled blocked image signal Sb is coded on a field basis (step S23).

On the other hand, as a result of the above determination processing, when the block-based image signal Sb should be subjected to frame-based downsampling, the blocked image signal Sb is supplied to the frame-unit downsampler 32a. The input selection switch 3a is switched based on the mode signal Sha so as to be supplied, and the block image signal Sb is downsampled in frame units by the downsampler 32a (step S3). 24) Further, the downsampled blocked image signal Sb is encoded in frame units by the frame unit encoder 35 (step S25).

At this time, the output selection switch 4a sets the above according to the mode signal Sma. One of the outputs S c1 and S c2 of both encoders 34 and 35 is selected, and the selected signal is output as an image coded signal S c.

Further, the mode signal, that is, an identification signal indicating in which unit of the frame or the field the down-sampling is performed is encoded and output as an encoded mode signal S mac (step S 26).

The dual image encoding apparatus 120a according to Embodiment 3 having such a configuration has the following effects.

In other words, when the encoding process of the image signal is performed in units of blocks, if the still image signal is encoded in units of frames, the encoding process can be performed efficiently. It is known that encoding can be performed efficiently if encoding is performed in field units. In addition, for a still input image signal, the downsampling is performed in units of frames to prevent deterioration of the spatial resolution in the vertical direction, and for an image signal that moves between fields, the downsampling is performed in units of fields to reduce the time. It is possible to prevent image quality deterioration in the direction.

Therefore, the ability to perform the two processes of down-sampling the blocked image signal and the encoding process of the blocked image signal on a frame-by-frame basis, and determine whether these two processes should be performed on a field-by-field basis. By performing the switching for each of the processes, the mode signal for switching between the field unit and the frame unit can be shared for each process, and the mode signal is used for the encoding process and the down sampling process. And save overhead information for separate encoding.

As described above, in the present embodiment, the down-sampling process and the encoding process are performed for a still image signal in units of frames, and the down-sampling process and the encoding process are performed for an image signal that moves between fields. Since the encoding process is performed, a combination of the down-sampling process and the encoding process that is not so effective in practical use, that is, a combination of the down-sampling process in the frame unit and the encoding process in the field unit, and By excluding the combination of field-based downsampling and frame-based encoding, the mode signal is converted to field-based or frame-based. It is possible to realize only one bit of information per block, which identifies the frame unit.

Embodiment 4.

FIG. 7 is a diagram illustrating an image decoding device according to a fourth embodiment of the present invention. In the figure, 120b is an image decoding device that performs a decoding process with up-sampling on the block image signal Sc encoded by the image coding device of the third embodiment. is there.

The image coding apparatus 120b decodes the mode coded signal S mac and outputs a decoded mode signal S indicating whether the down-sampling process and the coding process are performed in a frame unit or a field unit. A mode decoding circuit 6b for outputting mae is provided. Further, the image decoding device 120b includes a field unit decoder 72 for decoding the image coded signal S c on a field basis, and an output S e 11 thereof on a field basis. A field unit upsampler 6 1 b for sampling, a frame unit decoder 73 for decoding the image coded signal Sc in frame units, and a frame unit upsampling the output Se 22 in frame units Up And a sampler 62b.

In the image decoding apparatus 120b, an input selection switch 7b is provided in a stage preceding the decoders 72 and 73, and an output selection switch 8b is provided in a stage subsequent to the decoders. The input selection switch 7b supplies the image coded signal Sc to one of the two decoders according to the decoding mode signal S mae, and the output selection switch 8b outputs According to the decoding mode signal S mae, one of the outputs S ul and S u 2 of the two up-samplers is selected and output as an image decoding signal S u.

In other words, when the decoding mode signal S mae indicates downsampling and encoding in field units, the input selection switch 7 b connects the input of the field unit decoder 72 to the output selection switch 8 b Selects the output of the field unit upsampler 6 lb, and if the decoding mode signal S mae indicates down sampling and encoding in frame units, the input selection switch 7 b The input of the frame unit decoder 73 is used as an input, and the output selection switch 8 b is used as a frame unit amplifier. The output of the sampler 62b is selected, and the decoded image signal Su is output as a selected output from the output selection switch 8b.

Next, the operation will be described.

FIG. 8 is a flowchart illustrating the decoding process by the image decoding device 120b.

First, when the mode coded signal S mac and the image coded signal Sc are input to the image decoding device 120b, the mode coded signal S mac is decoded by the mode decoding circuit 6b. Then, a decoding mode signal Smae indicating whether the downsampling and the encoding process are performed in the field unit or the frame unit is output (step S30). Then, in accordance with the decoding mode signal S mae, the input selection switch 7 selects one of the inputs of the field unit decoder 72 and the frame unit decoder 73, and the output selection switch 8 One of the outputs of the field unit upsampler 61b and the frame unit upsampler 62b is selected (step S30a).

In other words, when the image coded signal Sc is a signal that has been downsampled and coded in field units, the above-described cracked image coded signal Sc is converted into a field unit decoder. Decoding is performed on a field basis at 72 (step S31), and the output Se11 is further upsampled on a field basis at the field unit upsampler 61b (step S32). On the other hand, when the coded image signal Sc has been subjected to down-sampling and coding processing in frame units, the block-coded image coded signal Sc is converted to the frame unit decoder 7. In step 3, the data is decrypted in frame units (step S33), and the output Se22 is output in the frame unit upsampler 62b to be upsampled in frame units (step 34). Then, the output of any one of the up-samplers is output as a decoded image signal Su via the output selection switch 8b.

As described above, the image decoding apparatus 120b according to the fourth embodiment decodes the mode coded signal S mac, and performs down-sampling and coding processing for the image coded signal S c on a field-by-field basis. The decoding mode that indicates which unit A mode decoding circuit 6b for outputting a decoded signal S mae, and performs decoding and up-sampling processing on the coded block image signal S mac according to the decoding mode signal S mae in units of fields or frames. Since the encoding is performed in units, the image coded signal corresponding to the still image is correctly decoded without preventing the spatial resolution in the vertical direction by decoding and upsampling in units of frames. An image coded signal corresponding to a moving image is correctly decoded by field-based decoding and assampling without preventing deterioration in image quality in the time direction.

As a result, for both the still image and the moving image, the image quality can be prevented from deteriorating due to the decoding process involving upsampling.

Embodiment 5

FIG. 9 is a block diagram for explaining an image coding apparatus according to Embodiment 5 of the present invention. In the figure, reference numeral 130a denotes an image coding apparatus according to the fifth embodiment which performs an encoding process with down-sampling on a blocked input image signal (blocked image signal) Sb. .

The image encoding apparatus 130a encodes a motion vector Smv indicating a motion of an object on a display processor of a predetermined size that divides a display screen, and generates a motion vector coded signal Cm. A motion vector encoding circuit 9 that outputs V and a motion vector S mv corresponding to each block are input, and the input image signal S b corresponding to each block is downsampled in frame units. And a mode determination circuit 8 for determining whether the down sampling should be performed in units of blocks or in units of fields, and outputting a mode signal S mm corresponding to the determination result. More specifically, the mode determination circuit 8 compares the magnitude of the motion vector S mv with a predetermined value, and if the magnitude of the motion vector is equal to or greater than the predetermined value, the mode is determined in units of fields. A mode signal S mm indicating that sampling should be performed is output. If the size of the motion vector is smaller than a predetermined value, a mode signal S mm indicating that down sampling should be performed in frame units is output. Here, the motion vector corresponding to each of the above blockings may have been detected in advance by the motion vector detecting means outside the present image encoding device.

In addition, the present image encoding device 130a converts the above-mentioned blocked image signal Sb into a field. It has a field unit downsampler 31a for downsampling in block units and a frame unit downsampler 32a for downsampling the block image signal Sb in frame units.

Then, in the image encoding device 130a, an input selection switch 3c is provided upstream of the downsamplers 31a and 32a, and an output selection switch 4c is provided downstream of the downsamplers. The input selection switch 3c supplies the blocked image signal Sb to one of the downsamplers in accordance with the mode signal Sinm, and the output selection switch 4c c is such that one of the outputs S c1 and S c2 of the both down-samplers is selected according to the mode signal S mm and output as an image coded signal S cc.

In other words, when the mode signal S mm indicates that the block image signal S b should be subjected to the field unit encoding process, the input selection switch 3 c is used as the input of the field unit downsampler 31 a. The output selection switch 4c selects the output of the down-sampler 31a, and determines that the mode signal S mm should be subjected to the frame-based coding process on the block image signal Sb. In this case, the input selection switch 33a selects the input of the frame-based downsampler 3 and the output selection switch 4c selects the output of the downsampler 32a. .

Further, in the image encoding device 130a, the output of the output selection switch 4c is input to the image encoding circuit 30a, and the motion vector is output to the image encoding circuit 30a. The motion compensation encoding process with reference to Smv is performed and output as an encoded image signal Sc.

Next, the operation will be described.

FIG. 10 is a flowchart showing the encoding process performed by the image encoding device _130a.

First, when the input image signal S b and the motion vector S mv of each block are input to the image encoding device 130a, the motion vector encoding circuit 9 The vector Smv is encoded, and a motion vector encoded signal CmV is output (step S40). Next, the mode determination circuit 8 operates from the above motion vector. Is determined (step S41), it is determined whether the magnitude of the motion is greater than a predetermined value, and a mode signal Smm corresponding to the determination result is output (step S41). 4 2).

Then, according to the determination result, a downsample process is performed on the blocked image signal Sb. That is, when the value of the motion vector is larger than the predetermined value, the input selection switch 3c is set on the basis of the mode signal Smm so that the blocked image signal Sb is supplied to the field unit downsampler 31a. The down-sampler 31a down-samples the blocked image signal Sb in field units (step S22).

On the other hand, if the result of the above determination processing indicates that the value of the motion vector is smaller than the predetermined value, the input selection switch 33 is used so that the above-mentioned blocked image signal Sb is supplied to the frame unit downsampler 32a. a is switched based on the mode signal Smm, and the block image signal Sb is down-sampled in frame units by the downsampler 32a (step S24).

At this time, the output selection switch 4c selects and selects one of the outputs Sc1, Sc2 of the down-samplers 31a and 32a in accordance with the mode signal Smm. The down-sampled signal is output to the image encoding circuit 30a, and the down-sampled signal is subjected to an encoding process with reference to a motion vector on a block basis in the circuit 30a (Step S). 43) is output as an image coded signal Sc.

In the image coding apparatus 130a according to the fifth embodiment, as in the first and third embodiments, whether the down-sampling processing is performed in a field unit or a frame unit based on an input image signal is determined. Instead of determining the size of the motion vector, it estimates whether the image is a still image or a moving image based on the size of the motion vector, and switches between a downsample in units of finolade and a downsample in units of frames. Therefore, as described in the first and third embodiments, the still image signal is down-sampled in frame units, and the moving image signal is down-sampled in field units. In addition to the effect of preventing image quality degradation due to encoding with downsampling, the downsampling based on the size of the motion vector By switching on a sample basis, the number of coding bits required for the mode signal can be reduced, and further, the image quality substantially equal to that of the first and third embodiments can be obtained.

In the fifth embodiment, it is determined on a block-by-block basis whether the down-sampling process of the blocked image signal Sb is performed in a field unit or a frame unit. The unit is switched between the down sampling process and the down sampling process.However, the switching of the down sampling process does not necessarily have to be determined and performed in units of blocks.For example, the switching of the down sampling process is determined in units of several blocks. You can do it.

Embodiment 6

FIG. 11 is a block diagram for explaining an image decoding apparatus according to Embodiment 6 of the present invention. In the figure, 13 Ob is the present embodiment that applies a decoding process with up-sampling to a block image signal Sc encoded by the image encoding device 130a of the fifth embodiment. 20 is an image decoding device according to a sixth aspect.

The image decoding apparatus 13 0 b includes a motion vector decoder 10 that decodes the motion vector coded signal C mV and outputs a decoded motion vector E m V. An image decoding circuit 40 that decodes the image coded signal Sc and outputs the image decoded signal Se with reference to the vector E m V, and a decoding motion vector E corresponding to each block. With m V as input, it is determined on a block-by-block basis whether the image coded signal Sc corresponding to each block should be sampled in frames or assembled in fields, and the mode according to the judgment result The signal Sme has a mode determination circuit 11.

Specifically, the mode determination circuit 11 compares the magnitude of the decoding motion vector EmV with a predetermined value, and if the size of the decoding motion vector is equal to or more than the predetermined value, the file A mode signal Sme indicating that upsampling should be performed in units of code is output, and if the magnitude of the decoding motion vector EmV is less than a predetermined value, it indicates that upsampling should be performed in units of frames. The mode signal S me is output. The mode signal S me is the same as that in the image encoding device 130a of the fifth embodiment shown in FIG. Down sample processing If this is done, the up-sampling process in the field unit is also performed in the image decoding device 130b in FIG. 11 and the down-sampling process in the frame unit in the image coding device 130a in FIG. Is performed, the up-sampling process is also performed for each frame in the image decoding apparatus 130b of FIG.

In the image decoding apparatus 130b according to the sixth embodiment, the output Se of the image decoding circuit 40 is provided before the two upsamplers 6lb and 62b in the decoding motion vector. An input selection switch 7c is provided to supply one of the two up-samplers based on the current Em V, and the outputs S u1, S of the two up-samplers are provided based on the decoding motion vector Em V. An output selection switch 8c for selecting and outputting one of u2 is provided.

Here, the switches 7 c and 8 c select the input and output of the field unit upsampler 6 lb when the decoding motion vector Em V indicates downsampling in the field unit. When the decoding motion vector Em V indicates a downsample in frame unit, the input and output of the upsampler 62b in frame unit are selected.

Next, the operation will be described.

FIG. 12 is a flowchart illustrating an image decoding process performed by the image decoding apparatus 130b according to the sixth embodiment.

First, when the motion vector coded signal CmV and the coded image signal Sc are input to the image decoding device 13 Ob, the motion vector decoding circuit 10 performs the motion vector decoding. The toll coded signal CmV is decoded, and a decoded motion vector EmV is generated (step S50). Next, in the image decoding circuit 40, the decoded image signal S e is output in a block unit with reference to the image coded signal S c power decoding operation vector Em V and a decoded image signal Se is output (step S 51).

Next, the mode determining circuit 11 determines the magnitude of the motion of the image of each block from the decoded motion vector Em V (step S41), and determines whether the magnitude of the motion is larger than a predetermined value. They are compared (step S42).

If the magnitude of the motion is larger than a predetermined value, the input selection is performed so that the output S e of the image decoding circuit is supplied to the field unit upsampler 6 1 b. The switch 7c is switched based on the decoding motion vector Emv, and the image decoding output Se is up-sampled in field units by the upsampler 61b (step S32). On the other hand, if the magnitude of the motion is smaller than the predetermined value, the input selection switch 7c is used to set the decoding motion vector so that the output Se of the image decoding circuit is supplied to the frame unit upsampler 62b. The image decoding output Se is up-sampled in frame units by the up-sampler 62b (step S34). At this time, the output selection switch 8c selects one of the two upsamplers 61b and 62 according to the decoding motion vector EmV, and the output selection switch 8c From c, a predetermined upsampled image decoding output S u is output.

In the image decoding apparatus 13 Ob according to the sixth embodiment having such a configuration, a motion vector decoding circuit 10 for decoding the coding motion vector C xn v is provided, and the decoding motion vector Since the still image or the moving image is estimated based on the magnitude of the torque EmV, and the upsampling is switched between the field-based upsampling and the frame-based upsampling, the image according to the fifth embodiment is used. By the same operation principle as that of the encoder 130a, it is possible to correctly determine whether the blocked image signal Sb should be up-sampled in units of fields or upsampled in units of frames.

As a result, with respect to the block image signal Sc of the still image, the decoding of the image coded signal is correctly performed by the decoding process with the up sample in the frame unit to prevent the deterioration of the spatial resolution in the vertical direction. For a video signal of a moving image, decoding processing involving upsampling in units of fields can correctly decode an image-encoded signal and prevent deterioration in image quality in the time direction.

In the sixth embodiment, whether to perform the up-sampling process of the blocked image signal Sc in a field unit or a frame unit is determined in units of a block, and the up-sampling process in the field unit and the frame unit are performed. Switching between up-sampling processing and unit up-sampling processing is not necessary. Switching of up-sampling processing need not necessarily be performed on a block-by-block basis.For example, switching of up-sampling processing is determined on a per-block basis. You can do it.

Further, the configuration of the image coding device or the image decoding device described in each of the above embodiments is described. By recording an encoding or decoding program for realizing the configuration on a data storage medium such as a floppy disk, the processing described in each of the above embodiments can be easily performed by an independent computer system. It can be implemented.

FIG. 13 shows a case where the image encoding process or the image decoding process of the first to sixth embodiments is performed by a computer system using a floppy disk storing the encoding or decoding program. FIG.

Fig. 13 (b) shows the external appearance, cross-sectional structure, and floppy disk of the floppy disk as viewed from the front, and Fig. 13 (a) shows the physical format of the floppy disk, which is the main body of the recording medium. An example is shown. The floppy disk FD is built in the case F. On the surface of the disk, a plurality of tracks Tr are formed concentrically from the outer circumference toward the inner circumference, and each track has 16 sectors in the angular direction. It is divided into S e. Therefore, in the floppy disk storing the program, data as the program is recorded in an area allocated on the floppy disk FD.

FIG. 13 (c) shows a configuration for recording and reproducing the program on a floppy disk FD. When the above program is recorded on the floppy disk FD, data as the above program is written from the computer system CS via a floppy disk drive. When the encoding or decoding device is constructed in the computer system Cs by a program in the floppy disk FD, the program is read out from the floppy disk FD by the floppy disk drive F DD and the computer system C forward to s. In the above description, the description has been made using a floppy disk as a data recording medium, but the same can be done using an optical disk. Further, the recording medium is not limited to this, and the present invention can be similarly implemented as long as the program can be recorded, such as an IC card or a ROM cassette. Industrial applicability

As described above, the image encoding method, the image decoding method, and the image encoding apparatus according to the present invention The image and data decoding apparatus and the data recording medium perform the compression or decompression processing of the interlaced image signal with high coding efficiency while suppressing the image deterioration of both still images and moving images. This is extremely useful as a means of realizing image coding and image decoding in a system for transmitting and storing image signals. Suitable for decompression processing.

Claims

The scope of the claims

1. An image encoding method for performing an encoding process with downsampling on an image signal,

Based on the image signal, it is determined whether to downsample the image signal in units of fields or frames.

In accordance with the determination result, the downsampled image signal of the image signal in field units or frame units is encoded in display block units of a predetermined size for dividing a display screen,

A picture coded signal obtained by coding in the display block unit, and a mode code obtained by coding a mode signal indicating whether the down sampling is performed in a frame unit or a field unit. An image encoding method characterized by outputting an encoded signal.

2. An image decoding method for decoding an image encoded signal and a mode encoded signal encoded by the image encoding method according to claim 1, wherein

Decoding the image coded signal in units of the display blocks to generate an image coded signal;

Decoding the mode encoded signal to generate a decoded mode signal;

When the decoding mode signal indicates that the downsampling is performed in units of frames, an image signal corresponding to a frame is generated from the decoded image signal, and the image signals are upsampled in units of frames. On the other hand, when the decoding mode signal indicates that the down-sampling is performed in units of fields, an image signal corresponding to a field is generated from the image decoding signal, and An image decoding method characterized by up-sampling and outputting an image signal in field units.

3. An image coding method for coding a blocked image signal obtained by blocking an image signal so as to correspond to each display block of a predetermined size that divides a display screen, wherein the blocked image signal is divided into fields. Or in frame units Determine whether to encode,

When encoding is to be performed on a field-by-field basis, the blocked image signal is down-sampled on a field-by-field basis, and the down-sampled signal is encoded on a field-by-field basis to generate an image-encoded signal;

When encoding is to be performed in frame units, the block image signal is downsampled in frame units, and the downsampled signal is encoded in frame units to generate an image encoded signal.

Outputting an image-encoded signal and a mode-encoded signal obtained by encoding a mode signal indicating whether the downsampling is performed in a frame unit or a field unit. .

4. An image decoding method for decoding an image encoded signal and a mode encoded signal encoded by the image encoding method according to claim 3, wherein

Decoding the mode coded signal to generate a decoded mode signal;

When the decoding mode signal indicates that the down-sampling has been performed in field units, the image-encoded signal is decoded in field units, and the decoded image signal is field-decoded. When the down-sampling is performed in frame units, the encoded image signal is decoded in frame units, and the decoded signal is output. An image decoding method characterized in that an image is upsampled in frame units and output.

5. An image code that generates an image-encoded signal by performing an encoding process with motion compensation on an image signal obtained by dividing the image signal into display blocks of a predetermined size that divide the display screen. Method,

When the size of the motion vector obtained from the image signal is equal to or larger than a predetermined value, the blocked image signal is down-sampled in field units, while the size of the motion vector obtained from the image signal is reduced. If the value is less than the predetermined value, the block image signal is down-sampled in frame units,

Encoding the downsampled blocked image signal;

Outputting an image coded signal obtained by coding the block image signal and a motion vector coded signal obtained by coding the motion vector. Image encoding method.

6. An image decoding method for decoding an image encoded signal generated by the image encoding method according to claim 5, wherein

Decoding the coded image signal to generate a coded image signal, and decoding the coded motion vector signal to generate a decoded motion vector signal;

When the size of the decoding motion vector is equal to or larger than a predetermined value, the decoded image signal is up-sampled and output in field units, while the size of the decoding motion vector is smaller than a predetermined value. Wherein the method further comprises sampling the decoded image signal in frame units and outputting the sampled image signal.

7. An image encoding device e for encoding an image signal,

Field down sampling means for down sampling the image signal in field units;

A frame down-sampling means for down-sampling the image signal in frame units;

Determining means for determining, based on the image signal, whether downsampling for the image signal should be performed in field units or frame units, and outputting a mode signal corresponding to the determination result;

A selection switch for selecting and outputting one of the output of the field down-sampling means and the output of the frame down-sampling means in accordance with the mode signal; and dividing a display screen into an output signal of the selection switch. Blocking means for blocking and outputting a block image signal corresponding to each display block of a predetermined size, and coding means for coding the block image signal in units of the display blocks to generate a picture coded signal. ,

Mode encoding means for encoding the mode signal to generate a mode encoded signal,

An image encoding device that outputs the image encoded signal and the mode encoded signal as output signals.

8. An image decoding device for decoding an image encoded signal and a mode encoded signal encoded by the image encoding method according to claim 1; Decoding means for decoding the image encoded signal for each display block to generate an image decoded signal;

A mode decoding means for decoding the mode encoded signal to generate a decoded mode signal;

A deblocking means for integrating a decoded image signal corresponding to the display block, which is an output of the decoding means, and converting the decoded image signal into an image signal corresponding to a frame or a field;

Frame up-sampling means for up-sampling the image signal integrated by the inverse block-forming means in frame units;

Field-up sampling means for up-sampling the image signal integrated by the reverse blocking means in field units;

A selection switch for selecting one of the outputs of the up-sampling means in accordance with the decoding mode signal;

An image decoding device, wherein an output of the selection switch is output as an image signal obtained by decoding the image encoded signal.

9. An image coding apparatus for coding a block image signal obtained by blocking an image signal so as to correspond to each display block of a predetermined size for dividing a display screen, wherein the block image signal is divided into fields and frames. Determination means for determining which of the units should be encoded, and outputting a mode signal corresponding to the determination result;

A field down-sampling means for down-sampling the blocked image signal in field units;

Field encoding means for encoding the output of the field unit ensemble means in field units;

Frame down sampling means for down sampling the block image signal in frame units;

Frame encoding means for encoding the output of the frame unit down sampling means in frame units;

A selection for selecting and outputting one of the outputs of the two encoding means in accordance with the mode signal. Switch and

Mode encoding means for encoding the mode signal from the determination means to generate a mode encoded signal,

An image coding apparatus, comprising: outputting a down-sampled coded signal from the selection switch and a mode coded signal from the mode coding means.

10. An image decoding apparatus for decoding an image encoded signal and a mode encoded signal encoded by the image encoding method according to claim 3, wherein:

A mode decoding means for decoding the mode coded signal and outputting a decoded mode signal;

Field decoding means for decoding the image coded signal in field units; field up sampling means for up-sampling the output of the field decoding means in field units;

Frame decoding means for decoding the image signal in frame units,

Frame sampling means for sampling the output of the frame decoding means in frame units;

A selection switch for selecting and outputting one of the outputs of the up-sampling means in accordance with the decoding mode signal,

An image decoding apparatus characterized by outputting an output of the selection switch as an image decoded signal obtained by decoding the image encoded signal.

1 1. The image signal is subjected to coding processing with motion compensation on the block-blocked image signal so as to correspond to each display block of a predetermined size, which divides the display screen. An image encoding device for outputting,

Determining means for determining whether or not the magnitude of a motion vector obtained from the blocked image signal is equal to or greater than a predetermined value, and outputting a mode signal corresponding to the determination result; A motion vector encoding means for encoding the motion vector to generate a motion vector encoded signal;

A field down-sampling means for down-sampling the block image signal in field units;

Frame down for down-sampling the block image signal in frame units Sample means;

A selection switch for selecting and outputting one output of the both down-sampling means in accordance with the mode signal;

Encoding means for encoding the output of the selection switch to generate an image encoded signal,

An image encoding device, which outputs a motion vector encoded signal generated by said motion vector encoding means and an image encoded signal encoded by said encoding means.

12. An image decoding device for decoding an image coded signal and a motion vector coded signal coded by the image coding method according to claim 5, wherein the image coded signal is Decoding means for decoding to generate a decoded image signal, and motion vector decoding means for decoding the motion vector coded signal to generate a decoded motion vector;

Determining means for determining whether or not the size of the decoding motion vector is equal to or greater than a predetermined value, and outputting a mode signal corresponding to the determination result;

Field up-sampling means for up-sampling the output of the decoding means in field units;

Frame up sampling means for up sampling the output of the decoding means in frame units;

A selection switch for selecting and outputting one of the outputs of the two above-mentioned sampling means in accordance with the mode signal,

An image decoding apparatus characterized in that an output of the selection switch is output as a decoded image signal.

13. A data storage medium storing, by a computer, a program for performing the image encoding method according to claim 1.

The above program is stored in the computer

A process of determining whether to perform downsampling on the image signal on a field basis or on a frame basis based on the image signal;

According to the result of the determination, the image signal is divided into fields or frames. Processing to downsample,

A process of encoding the downsampled image signal in display block units of a predetermined size for dividing a display screen; and

An image coded signal obtained by coding in the display block unit, and a mode coded signal obtained by coding a mode signal indicating whether the down sampling is performed in a frame unit or a field unit. A data storage medium characterized by causing a process to output the following.

14. A data storage medium storing, by a computer, a program for performing the image decoding method according to claim 2.

The above program is stored in the computer

A process of decoding the image encoded signal in units of the display blocks to generate an image decrypted signal;

A process of generating a mode signal by decoding the mode-coded signal; and, when the mode signal indicates that the down-sampling is performed in frame units, a process corresponding to a frame from the decoded image signal is performed. An image signal is generated, and the image signal is up-sampled and output in units of frames. When the mode signal indicates that down-sampling is performed in units of frames, a field corresponding to the field is obtained from the decoded image signal. A process of generating an image signal, and up-sampling and outputting the image signal in units of fields.

A data storage medium characterized by being made to perform.

15. A computer-readable data storage medium storing a program for performing the image encoding method according to claim 3.

The above program is stored in the computer

A process of determining whether to encode the block image signal in field units or frame units;

When encoding should be performed on a field-by-field basis, the blocked image signal is down-sampled on a field-by-field basis, the down-sampled signal is encoded on a field-by-field basis, and when encoded on a frame-by-frame basis, The block image signal is down-sampled in frame units, and the down-sampled signal is encoded in frame units. Encoding, and

An image encoded signal obtained by encoding the block image signal, and a mode encoding obtained by encoding a mode signal indicating whether the down sample is performed in a frame unit or a field unit. A data storage medium for performing a process of outputting a signal.

16. A data storage medium storing a program for performing the image decoding method according to claim 4 by a computer,

The above program is stored in the computer

Decoding the mode-encoded signal to generate a decoded mode signal; and, when the decoded mode signal indicates that the down-sampling has been performed in field units, the image-encoded signal is converted in field units. And the decoded image signal is up-sampled and output in field units. When the decoding mode signal indicates that the down-sampling is performed in frame units, A data storage medium characterized by performing a process of decoding a signal in frame units and up-sampling and outputting the decoded image signal in frame units.

17. A data storage medium storing, by a computer, a program for performing the image encoding method according to claim 5.

The above program is stored in the computer

When the size of the motion vector obtained from the image signal is equal to or larger than a predetermined value, the block image signal is down-sampled in field units, while the size of the motion vector obtained from the image signal is reduced. Is less than a predetermined value, a process of down-sampling the blocked image signal in frame units,

A process of encoding the down-sampled blocked image signal; and

A process of outputting an image coded signal obtained by coding the block image signal and a motion vector coded signal obtained by coding the motion vector. Characteristic data storage medium.

18. A data storage medium storing, by a computer, a program for performing the image decoding method according to claim 6. The above program is stored in the computer

A process of decoding the coded image signal to generate a decoded image signal, decoding the coded motion vector signal to generate a decoded motion vector signal, and processing the decoded motion vector. When the size is equal to or more than a predetermined value, the decoded image signal is up-sampled and output in field units, while when the size of the decoded motion vector is smaller than a predetermined value, the decoded image signal is output. The process of upsampling and outputting signals in frame units

A data storage medium characterized by being made to perform.