JP2006217480A - Coding apparatus and method, recording medium, program, image processing system, and image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of suppressing copying of analog data by deteriorating subsequent decoding results of similar coding and decoding when repeating a series of processes for digitizing and coding analog data and then decoding the digital coded data obtained. <P>SOLUTION: A block division unit 61 divides a received image into blocks each having a prescribed three-dimensional size bx (pixels in a horizontal direction) × by (pixels in a vertical direction) × bt (number of images). A feature quantity detection section 62 detects the feature quantity of each three-dimensional block (e.g. a maximum value, a minimum value of pixel values, and a dynamic range or the like). A block group classification section 63 classifies the three-dimensional blocks into block groups wherein the feature quantity is shared in common. A quantization table generating section 64 generates a quantization table comprising quantization representative values with respect to each block group. A quantization section 65 quantizes pixels belonging to each three-dimensional block by the ADRC (Adaptive Dynamic Range Coding) using the quantization table corresponding to the classified block group. The technology disclosed herein can be applied to video recorders. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an encoding apparatus and method, a recording medium, a program, an image processing system, and an image processing method, and more particularly to an encoding apparatus and method, a recording medium, and a program suitable for use in suppressing copying of analog data. The present invention relates to an image processing system and an image processing method.

  A general recording medium (for example, a cassette magnetic tape such as a DVD (Digital Versatile Disc) or VHS (Video Home System)) on which an image signal such as video content is recorded is reproduced by a reproduction device, and the reproduction result is analog data. Assuming that the data is supplied to a television receiver, the analog data supplied to the television receiver is branched and input to a predetermined recording device to create a copy of the video content. can do.

  However, since such a copy creation may infringe copyright, a method for preventing unauthorized copying of video content or the like has been proposed.

  Specifically, methods have been proposed in which scramble processing is performed on analog data output from the playback device, or output of analog data is prohibited (see, for example, Patent Document 1).

  According to the conventional method described above, illegal copying of analog data can be suppressed. However, there is a problem that a normal image cannot be displayed on a television receiver or the like to which the analog data is supplied.

Therefore, in order to solve the above-described problems, the present applicant performs encoding by paying attention to analog noise such as a phase shift when encoding analog data into digital data, thereby decoding the image quality after decoding. An invention for degrading the above has already been filed (for example, see Patent Document 2).
JP 2001-245270 A Japanese Patent Application Laid-Open No. 2004-289685

  According to the invention described in Patent Document 1, unauthorized copying of analog data can be suppressed. Further, according to the invention described in Patent Document 2, a normal image can be displayed on a television receiver or the like to which the analog data is supplied.

  However, the search for an invention that suppresses unauthorized copying of analog data is not limited to Patent Document 2, and a solution by the further invention of the above-described problem is demanded.

  The present invention has been made in view of such a situation, when analog data is digitized and encoded, and when a series of processes for decoding the resulting digitally encoded data is repeated, similar encoding, It is ensured that the second and subsequent decoding results are degraded in spite of decoding. As a result, copying of analog data can be suppressed.

  An encoding apparatus according to the present invention includes a blocking unit that blocks image data into blocks of a predetermined size, a detecting unit that detects a feature amount of image data in each block blocked by the blocking unit, and a detecting unit A block group generation unit that generates a block group by grouping blocks blocked by the block generation unit based on the feature amount detected by the block generation unit, and a block for each block group generated by the block group generation unit. Based on the frequency distribution of the image data in the blocks belonging to the group, a creation means for creating a quantization table composed of a plurality of quantized representative values, and the block group to which the image data of each block blocked by the blocking means belongs Quantization means for quantizing based on a quantization table corresponding to And it features.

  Noise can be added to the image data.

  The encoding apparatus according to the present invention may further include noise adding means for adding noise to the input image data.

  The image data may be decoded after being encoded at least once.

  The blocking unit can block a plurality of pieces of image data into three-dimensional blocks.

  For each block group generated by the block group generation unit, the creating unit equalizes the pixels included in the block group to a plurality of quantized representative values based on the frequency distribution of the image data in the blocks belonging to the block group. A plurality of quantization representative values can be determined so as to be distributed, and a quantization table can be created.

  The detection unit may detect at least a minimum value and a dynamic range of pixel values included in each block blocked by the blocking unit.

  The block group generation unit may generate a block group by grouping blocks having a common dynamic range of pixel values detected by the detection unit.

  The creation means includes a plurality of block groups generated by the block group generation means based on a frequency distribution of a difference value between a pixel value of each pixel of each block belonging to the block group and a minimum value of the pixel of the block. It is possible to create a quantization table composed of representative quantization values.

  The quantization means may output at least a quantization table and a quantization code which is a quantization result of image data of each block.

  The detection unit may detect at least a maximum value and a minimum value of pixel values included in each block blocked by the blocking unit.

  The block group generation unit may generate a block group by grouping blocks having the same maximum and minimum pixel values detected by the detection unit.

  The creation means is based on a frequency distribution of a difference value between a pixel value of each pixel of each block belonging to the block group and a minimum value of pixels common to the block group for each block group generated by the block group generation means. Thus, a quantization table composed of a plurality of quantization representative values can be created.

  The encoding apparatus of the present invention can further include an inverse quantization unit that inversely quantizes the output result of the quantization unit.

  The encoding method of the present invention includes a blocking step for blocking image data into blocks of a predetermined size, a detection step for detecting a feature amount of image data in each block blocked by the processing of the blocking step, Based on the feature quantity detected in the detection step process, the block group generation step for grouping each block blocked in the blocking step process to generate a block group, and the block group generation step process For each block group, the block is divided into blocks by a creation step for creating a quantization table composed of a plurality of quantized representative values based on the frequency distribution of image data in the blocks belonging to the block group, and the blocking step. The image data of each block is based on the quantization table corresponding to the block group to which it belongs. Characterized in that it comprises a quantization step of quantizing Te.

  Noise can be added to the image data.

  The encoding method of the present invention may further include a noise adding step for adding noise to the input image data.

  The image data may be decoded after being encoded at least once.

  The blocking step can block a plurality of pieces of image data into three-dimensional blocks.

  In the creation step, for each block group generated in the block group generation step, pixels included in the block group are converted into a plurality of quantized representative values based on the frequency distribution of image data in the blocks belonging to the block group. It is possible to create a quantization table by determining a plurality of quantization representative values so that they are evenly distributed.

  The detection step may detect at least a minimum value and a dynamic range of a pixel value included in each block that has been blocked by the process of the blocking step.

  In the block group generation step, blocks having a common dynamic range of pixel values detected in the detection step process can be grouped to generate a block group.

  The creating step is based on a frequency distribution of a difference value between a pixel value of each pixel of each block belonging to the block group and a minimum value of the pixel of the block for each block group generated by the process of the block group generating step. A quantization table composed of a plurality of quantization representative values can be created.

  The quantization step may output at least a quantization table and a quantization code that is a quantization result of image data of each block.

  In the detection step, at least a maximum value and a minimum value of pixel values of pixels included in each block formed by the block forming step can be detected.

  In the block group generation step, blocks having a common maximum value and minimum value of pixel values detected in the detection step can be grouped to generate a block group.

  In the creation step, for each block group generated in the block group generation step, the frequency distribution of the difference value between the pixel value of each pixel of each block belonging to the block group and the minimum pixel value common to the block group Based on the above, a quantization table composed of a plurality of representative quantization values can be created.

  The recording medium program of the present invention includes a blocking step for blocking image data into blocks of a predetermined size, and a detection step for detecting a feature amount of the image data in each block blocked by the processing of the blocking step; Based on the feature amount detected in the detection step process, the block group generation step generates a block group by grouping blocks blocked in the block step process, and the block group generation step process generates the block group. Each block group is divided into blocks by a creation step for creating a quantization table composed of a plurality of quantized representative values based on the frequency distribution of image data in the blocks belonging to the block group, and a process of the blocking step. The image data of each block is converted into a quantization table corresponding to the block group to which it belongs. Characterized in that it comprises a quantization step of quantizing, based on the Le.

  The program according to the present invention includes a blocking step for blocking image data into blocks of a predetermined size, a detection step for detecting a feature amount of image data in each block blocked by the processing of the blocking step, and a detection step Based on the feature amount detected in the process of step 1, a block group generation step for grouping each block blocked in the block step processing to generate a block group, and each block generated in the block group generation step process For each block group, a creation step for creating a quantization table including a plurality of quantization representative values based on the frequency distribution of image data in the blocks belonging to the block group, and each block that has been blocked by the processing of the blocking step Image data based on the quantization table corresponding to the block group to which it belongs. Characterized in that to execute a process including the quantization step for quantizing the computer Te.

  In the encoding apparatus, method, and program of the present invention, image data is divided into blocks of a predetermined size, the feature amount of the image data in each block is detected, and each block is based on the detected feature amount. Are grouped to generate a block group. Furthermore, for each block group, a quantization table consisting of a plurality of representative quantization values is created based on the frequency distribution of image data in the blocks belonging to the block group, and the image data of each block corresponds to the block group to which it belongs. Quantization is performed based on the quantization table.

  In the first image processing system of the present invention, the encoding unit blocks the image data into blocks of a predetermined size, and the feature amount of the image data in each block blocked by the blocking unit. A detection unit for detecting, a block group generation unit for generating a block group by grouping blocks blocked by the blocking unit based on the feature amount detected by the detection unit, and a block group generation unit For each block group, based on the frequency distribution of image data in the blocks belonging to the block group, a creation means for creating a quantization table composed of a plurality of quantization representative values, and each block blocked by the blocking means Image data based on the quantization table corresponding to the block group to which it belongs Characterized in that it comprises a quantizing means.

  The first image processing system of the present invention can further include a noise adding unit that adds noise to image data that is a decoding result of the decoding unit and supplies the image data to the encoding unit.

  According to a first image processing method of the present invention, a coding step in an encoding unit that blocks image data into blocks of a predetermined size, and features of the image data in each block that is blocked by the processing of the blocking step A block detecting step for detecting the amount, a block group generating step for generating a block group by grouping blocks blocked by the block forming step based on the feature amount detected by the detecting step processing, and a block For each block group generated in the process of the group generation step, a creation step for creating a quantization table composed of a plurality of quantization representative values based on the frequency distribution of image data in the blocks belonging to the block group, and blocking The image data of each block that was blocked in the step process is applied to the block group to which it belongs. Characterized in that it comprises a quantization step of quantizing, based on the quantization table.

  The first image processing method of the present invention may further include a noise addition step of adding noise to image data that is a decoding result of the decoding unit and supplying the image data to the encoding unit in the noise adding unit.

  In the first image processing system and image processing method of the present invention, the encoding unit blocks the image data into blocks of a predetermined size, detects the feature amount of the image data in each block, and detects the detected features. Based on the quantity, each block is grouped to generate a block group. Furthermore, for each block group, a quantization table consisting of a plurality of representative quantization values is created based on the frequency distribution of image data in the blocks belonging to the block group, and the image data of each block corresponds to the block group to which it belongs. Quantization is performed based on the quantization table.

  In the second image processing system of the present invention, the decoding unit includes at least a quantization table from encoded data that is a result of encoding the image data into blocks by the encoding unit. And a detecting means for detecting the quantization code, and a decoding means for decoding the block-unit image data from the quantization code by referring to the quantization table.

  The second image processing system of the present invention can further include a noise adding unit that adds noise to image data that is a decoding result of the decoding unit and supplies the image data to the encoding unit.

  According to a second image processing method of the present invention, in the decoding unit, at least a quantization table is obtained from encoded data that is a result obtained by encoding image data in blocks by the encoding unit. And a detection step of detecting the quantization code, and a decoding step of decoding the block-unit image data from the quantization code by referring to the quantization table.

  The second image processing method of the present invention may further include a noise adding step in the noise adding unit that adds noise to the image data that is a decoding result of the decoding unit and supplies the image data to the encoding unit.

  In the second image processing system and image processing method of the present invention, from the encoded data that is the result of the decoding unit encoding the image data into blocks by the decoding unit, and encoding the data in units of blocks. At least the quantization table and the quantization code are detected, and the quantization table is referred to, thereby decoding the block-unit image data from the quantization code.

  According to the present invention, when analog data is digitized and encoded, and a series of processes for decoding the resulting digitally encoded data is repeated, the second and subsequent times are performed regardless of similar encoding and decoding. Can be degraded. Therefore, copying of analog data can be suppressed.

  Embodiments of the present invention will be described below. Correspondences between constituent elements described in the claims and specific examples in the embodiments of the present invention are exemplified as follows. This description is to confirm that specific examples supporting the invention described in the claims are described in the embodiments of the invention. Therefore, even though there are specific examples that are described in the embodiment of the invention but are not described here as corresponding to the configuration requirements, the specific examples are not included in the configuration. It does not mean that it does not correspond to a requirement. On the contrary, even if a specific example is described here as corresponding to a configuration requirement, this means that the specific example does not correspond to a configuration requirement other than the configuration requirement. not.

  Further, this description does not mean that all the inventions corresponding to the specific examples described in the embodiments of the invention are described in the claims. In other words, this description is an invention corresponding to the specific example described in the embodiment of the invention, and the existence of an invention not described in the claims of this application, that is, in the future, a divisional application will be made. It does not deny the existence of an invention that is added by correction.

  The encoding device according to claim 1 (for example, the encoding device 16 of FIG. 1) includes blocking means (for example, the block dividing unit 61 of FIG. 5) for blocking image data into blocks of a predetermined size, Detection means (for example, feature quantity detection unit 62 in FIG. 5) for detecting the feature amount of the image data in each block blocked by the blocking means, and blocking means based on the feature quantity detected by the detection means A block group generation unit (for example, block group classification unit 63 in FIG. 5) that groups the blocks that are blocked by the block group generation unit, and a block group for each block group generated by the block group generation unit Creating means for creating a quantization table comprising a plurality of representative quantization values based on the frequency distribution of image data in blocks belonging to For example, the quantization table creating unit 64 in FIG. 5 and the quantization unit (for example, the quantization unit that quantizes the image data of each block blocked by the blocking unit based on the quantization table corresponding to the block group to which the block belongs) And a quantization unit 65) of FIG.

  The encoding apparatus according to claim 3 further includes noise adding means (for example, noise adding unit 42 in FIG. 1) for adding noise to the input image data.

  The encoding apparatus according to claim 14 further includes an inverse quantization means (for example, the decoding unit 31-2 in FIG. 1) for inversely quantizing the output result of the quantization means.

  The encoding method according to claim 15 includes a blocking step (for example, step S2 in FIG. 6) for blocking image data into blocks of a predetermined size, and each block blocked by the processing of the blocking step. Based on the detection step (for example, step S3 in FIG. 6) for detecting the feature amount of the image data, and the feature amount detected by the detection step processing, the blocks that are blocked by the blocking step processing are grouped. Based on the frequency distribution of the image data in the blocks belonging to the block group, for each block group generated in the block group generation step (for example, step S4 in FIG. 6) and the block group generation step processing The creation step for creating a quantization table comprising a plurality of quantization representative values (for example, the step of FIG. 6). S5), and a quantization step (for example, step S6 in FIG. 6) that quantizes the image data of each block that has been blocked by the processing of the blocking step based on the quantization table corresponding to the block group to which the block belongs. Including.

  The encoding method according to claim 17 further includes a noise adding step (for example, step S1 in FIG. 6) for adding noise to the input image data.

  The image processing system (for example, the image display system 1 of FIG. 1) according to claim 30, wherein an encoding unit (for example, the encoding unit 22-2 of FIG. 1) blocks image data into blocks of a predetermined size. Block forming means (for example, the block dividing unit 61 in FIG. 5) and detecting means for detecting the feature amount of the image data in each block blocked by the blocking means (for example, the feature amount detecting unit 62 in FIG. 5). ) And a block group generation unit (for example, block group classification unit 63 in FIG. 5) that generates a block group by grouping the blocks blocked by the blocking unit based on the feature amount detected by the detection unit For each block group generated by the block group generation means based on the frequency distribution of the image data in the blocks belonging to the block group. Corresponding to the block group to which the creation means (for example, the quantization table creation unit 64 in FIG. 5) for creating the quantization table consisting of the quantization representative values and the image data of each block blocked by the blocking means belong Quantization means (for example, the quantization unit 65 in FIG. 5) that performs quantization based on the quantization table.

  The image processing system according to claim 31 further includes a noise adding unit (for example, the noise adding unit in FIG. 1) that adds noise to image data that is a decoding result of the decoding unit and supplies the image data to the encoding unit. Prepare.

  An image processing method according to a thirty-second aspect is the block forming step (for example, FIG. 6) in which the image data is blocked into blocks of a predetermined size in the encoding unit (for example, the encoding unit 22-2 in FIG. 1). Step S2), a detection step (for example, step S3 in FIG. 6) for detecting the feature amount of the image data in each block that has been blocked by the processing of the blocking step, and the feature amount detected by the processing of the detection step Based on the block group generation step (for example, step S4 in FIG. 6) for grouping the blocks that have been blocked by the blocking step processing to generate a block group, and the block group generation step processing A block group consists of a plurality of quantized representative values based on the frequency distribution of image data in blocks belonging to the block group. A creation step for creating a child table (for example, step S5 in FIG. 6), and the image data of each block that has been blocked by the process of the blocking step are quantized based on the quantization table corresponding to the block group to which the block belongs. Quantization step (for example, step S6 in FIG. 6).

  In an image processing method according to a thirty-third aspect, noise is added to image data which is a decoding result of the decoding unit in a noise adding unit (for example, the noise adding unit in FIG. 1), and is supplied to the encoding unit. A noise addition step (for example, step S1 in FIG. 6) is further included.

  The image processing system according to claim 34 (for example, the image display system 1 in FIG. 1) is configured such that the decoding unit (for example, the decoding unit 31-1 of the reproduction device 14 in FIG. 1) uses the encoding unit to generate image data. Is a detection means for detecting at least a quantization table and a quantization code from encoded data that is a result of being block-coded into predetermined blocks and encoded in units of blocks (for example, the encoded data separation unit 71 in FIG. 11) And decoding means (for example, the block decoding unit 72 in FIG. 11) for decoding block-unit image data from the quantization code by referring to the quantization table.

  The image processing system according to claim 35 further includes a noise adding unit (for example, the noise adding unit in FIG. 1) that adds noise to the image data that is a decoding result of the decoding unit and supplies the image data to the encoding unit. Prepare.

  In the image processing method according to claim 36, in the decoding unit (for example, the decoding unit 31-1 of the playback device 14 in FIG. 1), the image data is blocked into predetermined blocks by the encoding unit, and is in block units. The detection step (for example, steps S11 and S12 in FIG. 12) for detecting at least the quantization table and the quantization code from the encoded data that is the result of the encoding in FIG. 12, and the quantization table by referring to the quantization table A decoding step (for example, step S13 in FIG. 12) for decoding block-unit image data from the code.

  In an image processing method according to a thirty-seventh aspect, a noise addition step (for example, step S1 in FIG. 6) adds noise to image data that is a decoding result of the decoding unit and supplies the image data to the encoding unit. ).

  The correspondence relationship between the constituents described in the claims of the program of the present invention and the program of the present invention and the specific example in the embodiment of the present invention is the encoding of the present invention described above. Since it is the same as that of the method, its description is omitted.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

FIG. 1 shows a configuration example of an image display system to which the present invention is applied. The image display system 1 includes an encoding device 12 that encodes an analog image signal V _an0 input from a tuner 11 or the like and records the encoded image data on a recording medium 13, and encoded digital data V _{rd, 0} recorded on the recording medium 13. reproducing device 14 the reading and reproducing, codes to be recorded on the display 15, the playback apparatus 14 by encoding an analog image signal V _an1 supplied from the recording medium 17 to display an analog image signal V _an1 supplied from the reproducing apparatus 14 _And the display 18 for displaying the analog image signal _Van2 supplied from the decoding device 16.

The tuner 11 receives a television broadcast, for example, and outputs an analog image signal V _an0 obtained as a result to the encoding device 12.

The encoding device 12 digitizes the analog image signal V _an0 input from the tuner 11 and outputs the resulting digital image signal V _dg1,0 to the encoding unit 22-1 (A / D). ) 21, an encoding unit 22-1 that encodes the digital image signal V _dg1,0 and outputs the resulting encoded digital image data V _{cd, 0} to the recording unit 23, and encoded digital image data V _{cd, The} recording unit 23 is configured to record ₀ on the recording medium 13.

  The recording media 13 and 17 include, for example, a magnetic disk (including a flexible disk), an optical disk (including a CD-ROM (Compact Disc-Read Only Memory) and a DVD), a magneto-optical disk (including an MD (Mini Disc)), Alternatively, it consists of a semiconductor memory or the like.

The playback device 14 decodes the digital encoded data V _{rd, 0} read from the recording medium 13, and outputs a digital image signal V _dg0 obtained as a result to the digital-analog converter 32, and a digital The image signal V _dg0 is _converted into an analog signal, and the resulting analog image signal V _an1 is output from the display 15 and the digital / analog conversion section (D / A) 32 that outputs to the encoding device 16.

In the digital-analog conversion unit 32, when the digital image signal V _dg0 is converted into an analog signal due to the characteristics of a general analog-digital conversion circuit, the analog image signal V _an1 obtained as a result is converted into analog noise (referred to as white noise). Distortion generated by adding a high frequency component, distortion due to phase shift, and the like) are added.

Here, distortion caused by adding a high frequency component will be described with reference to FIG. It is _{assumed that} the parallel five pixels of the digital image signal V _dg0 before digital-analog conversion in the digital-analog converter 32 have the same pixel value as shown on the left side of the figure. When the analog image signal V _an1 to which high-frequency component distortion is added by digital-analog conversion is digitized by the analog-digital conversion unit 41 in the _subsequent stage, fluctuations occur in the same pixel values as shown on the right side of the figure. . This change is not regular and not uniform. Further, distortion of high frequency components is similarly applied not only in the horizontal direction but also in the vertical direction. Hereinafter, this distortion added through digital-analog conversion and analog-digital conversion is also referred to as white noise.

Next, distortion due to phase shift will be described with reference to FIG. The positions indicated by “●” in FIG. 3 are the pixels constituting the digital image signal V _dg1 digitized by the analog-to-digital converter 41 after distortion caused by the phase shift of the signal by the digital-to-analog converter 32 occurs. An example of the pixel position of data is shown. A position indicated by “◯” indicates a correct pixel position when the phase is not shifted. In the figure, the phase is shifted by φh in the horizontal direction and by φv in the vertical direction. φh is the phase shift width in the horizontal direction, and φv is the phase shift width in the vertical direction. As can be seen from the figure, the phase shift width φh in the horizontal direction may be narrower than the pixel interval, but the phase shift width φv in the vertical direction is only an integral multiple of the pixel interval. Note that the phase shift may occur only in one of the horizontal direction and the vertical direction. Hereinafter, distortion due to phase shift is also simply referred to as phase shift.

  Returning to FIG. The displays 15 and 17 are composed of a CRT (Cathode Ray Tube), an LCD (Liquid Crystal Display), or the like, and display an image corresponding to an input analog image signal.

The encoding device 16 digitizes the analog image signal V _an1 input from the reproduction device 14 and outputs the resulting digital image signal V _dg1 to the encoding unit 22-2, digital image signal 41 The encoding unit 22-2 that encodes V _dg1 and _{outputs the} resulting encoded digital image data V _cd to the recording unit 44 and the decoding unit 31-2, and the encoded digital image data V _cd to the recording medium 17 The recording unit 44 is configured to record and read the encoded digital image data V _rd recorded on the recording medium 17 and supply it to the decoding unit 31-2.

Further, the encoding device 16 decodes the encoded digital image data V _cd supplied from the encoding unit 22-2 or the encoded digital image data V _rd supplied from the recording unit 44, and a digital image obtained as a result thereof From the decoding unit 31-2 that outputs the signal V _dg2 to the digital-analog conversion unit 46 and the digital-analog conversion unit 46 that converts the digital image signal V _dg2 into an analog signal and outputs the resulting analog image signal V _an2 to the display 18 Composed.

Incidentally, the digital image signal V _dg1 output from the analog digital converter 41, (at least one of white noise or phase shift) analog noise to the analog image signal V _an1 before being digitized due to the has occurred _Thus , the pixel value slightly fluctuates as compared with the digital image signal V _dg0 output from the decoding unit 31-1 (that is, a state in which noise is _added ).

Further, a noise adding unit 42 is built in the analog-digital conversion unit 41, and noise (white noise and noise corresponding to phase shift) is added to the analog image signal _Van1 before being intentionally digitized, and then digitized. You may make it do.

  The encoding unit 22-1 in the encoding device 12 and the encoding unit 22-2 in the encoding device 16 have the same configuration (described later). Hereinafter, when there is no need to distinguish between the encoding unit 22-1 and the encoding unit 22-2, they are simply referred to as the encoding unit 22.

  Also, the decoding unit 31-1 in the playback device 14 and the decoding unit 31-2 in the encoding device 16 have the same configuration (described later). Hereinafter, when there is no need to distinguish between the decoding unit 31-1 and the decoding unit 31-2, they are simply referred to as the decoding unit 31.

  Next, the operation of the image display system 1 will be described with reference to FIG. The image display system 1 encodes and decodes an original image, and encodes and decodes a “first encoded / decoded image” obtained as a result, to obtain a “second encoded / decoded image”. Is output. The definitions of “first encoded / decoded image” and “second encoded / decoded image” are as follows.

That is, the original image shown in FIG. A corresponds to the analog image signal _Van0 output from the tuner 11. The “first encoded / decoded image” shown in FIG. B obtained by encoding and decoding the original image corresponds to the digital image signal V _dg0 output from the decoding unit 31-1 of the playback device 14. . The “image in which distortion is added to the first encoded / decoded image” shown in FIG. 3C corresponds to the analog image signal _Van1 output from the digital-analog conversion unit 32 of the playback device 14. The “second encoded / decoded image” shown in FIG. 4D is a digital image signal V _dg2 output from the decoding unit 31-2 of the encoding device 16, or the recording device 17 is decoded by the reproduction device 14. This corresponds to a digital image signal or the like obtained as a result of decoding by the unit 31-1.

  Next, FIG. 5 shows a configuration example of the encoding unit 22. The encoding unit 22 divides an input image into three-dimensional blocks of a predetermined three-dimensional size bx (pixels in the horizontal direction) × by (pixels in the vertical direction) × bt (number of images), A feature amount detection unit 62 that detects a feature amount of a three-dimensional block (for example, a maximum value, a minimum value, or a dynamic range of pixel values), and a block that classifies each three-dimensional block into a block group in which the detected feature amount is common. A group classification unit 63, a quantization table creation unit 64 that creates a quantization table including quantization representative values for each block group, and a quantization table corresponding to each classified block group are used for each three-dimensional block. It comprises a quantizing unit 65 that performs quantization by ADRC (Adaptive Dynamic Range Coding).

  The encoding unit 22 performs a first operation (encoding process) or a second operation described below.

  The first operation (encoding process) of the encoding unit 22 will be described with reference to the flowchart of FIG. 6 using the encoding unit 22-2 of the encoding device 16 as an example.

First, as step S1, noise is added to the analog image signal _Van1 before being digitized by the noise adding unit 42 of the analog-digital converting unit 41. However, the process of step S1 may be omitted.

In step S2, the block division unit 61 converts the digital image signal V _dg1 (with noise added) input from the analog / digital conversion unit 41 into bx (pixel) × by (pixel) × bt as shown in FIG. The image is divided into (number of images) three-dimensional blocks and output to the feature amount detection unit 62. Therefore, each three-dimensional block includes pixels included in a two-dimensional area common to each of the consecutive bt images. Note that bx, by, and bt can be set arbitrarily.

In step S3, the feature amount detection unit 62 sets the feature amount of each three-dimensional block divided in the process of step S2, and the maximum value max, the minimum value min, and the maximum value of the pixel values of the pixels belonging to each three-dimensional block, The dynamic range dr which is the difference between the minimum values is detected.
dr = max-min (1)

In step S4, the block group classification unit 63 classifies each three-dimensional block into a block group having a common dynamic range as shown in FIG. For example, when the dynamic range of a certain three-dimensional block is dr _i , the three-dimensional block is classified into a dr _i group group. Note that the dynamic range blocks of the three-dimensional blocks classified into the same dynamic range block group are common, and the maximum value and the minimum value are not always common.

  In step S5, the quantization table creation unit 64 creates a quantization table including a plurality of quantization representative values for each block group into which the three-dimensional block is classified.

Specifically, first, as shown in FIG. 9A, for example, when g three-dimensional blocks are classified into the dr _i group group, m (included in each three-dimensional block j classified into the group group. = Bx × by × bt) pixel values L _{ij, k} (j = 1, 2,..., G) (k = 1, 2,..., M) and the minimum value min _j of each three-dimensional group. The difference value D _{ij, k} is calculated. The difference value D _{ij, k} is 0 to dr _i (= max _i −min _i ).
D _{ij, k} = L _{ij, k} −min _i (2)

As a result, g × m calculation results are obtained, and the frequency distribution of the difference values D _{i, w} (w = 0,..., Dr _i ) is obtained as shown in FIG. 9B. The frequency D _{i, wd} of the difference value D _{i, w} (w = 0,..., Dr _i ) is assumed.

Next, a value n _d is calculated by equally dividing the total number (m × g) of pixels included in the g three-dimensional blocks classified into the dr _i group by 2 ^b (b is bit allocation).
n _d = (m × g) / 2 ^b (3)

Then, the quantization width Δ _p (p = 1,..., Bm (= b ² )) is sequentially determined according to the following rules.
When n _d = ΣD _{i, wd} (Σ is the sum of wd = 0,..., w ₁ ), Δ ₁ = w ₁
When n _d = ΣD _{i, wd} (Σ is the sum of wd = w ₁ +1,..., w ₂ ), Δ ₂ = w ₂ −w ₁
...
When n _d = ΣD _{i, wd} (Σ is the sum of wd = w _bm−1 +1,..., w _bm ), Δ _bm = w _bm −w _bm−1

For example, when quantization is performed with bit allocation b = 2, the quantization width is determined so that the areas of the frequency distributions (A, B, C, and D in FIG. 9B) are equal, as shown in FIG. 9B. Will be.
Δ ₁ = w ₁
Δ ₂ = w ₂ −w ₁
Δ ₃ = w ₃ −w ₂
Δ ₄ = w ₄ −w ₃

After determining the quantization width _Δp in this way, a plurality of quantization representative values are determined. As shown in FIG. 10A, the quantization representative value is determined by the first determination method in which the middle of each quantization width _Δp is set as a quantization representative value, or as shown in FIG. 10B, each quantization width Δ The second determination method for determining the boundary of _p as the quantized representative value is adopted.

When the first determination method is adopted, the quantization representative value q _s (s = 1,..., B ² ) is as follows by taking the case of quantization with bit allocation b = 2 as an example.
q ₁ = w _1/2
q ₂ = w ₁ + (w ₂ −w ₁ ) / 2
q ₃ = w ₂ + (w ₃ −w ₂ ) / 2
q ₄ = w ₃ + (w ₄ −w ₃ ) / 2

When the second determination method is adopted, n _d is calculated using the following equation (4) instead of equation (3).
n _d = (m × g) / (2 ^b −1) (4)
Taking the case of quantization with bit allocation b = 2 as an example, the representative quantization value q _s (s = 1,..., B ² ) is as follows.
q ₁ = 0
q ₂ = w ₁
q ₃ = w ₂
q ₄ = w ₃

As described above, the plurality of quantized representative values q _s calculated for each block group, that is, the quantization table, is used in the subsequent quantization unit 65.

Returning to FIG. In step S6, the quantization unit 65 quantizes each three-dimensional block. Specifically, a quantization table corresponding to a block group to which a three-dimensional block to be quantized belongs is obtained, and a pixel value of each pixel included in the three-dimensional block and a plurality of (for example, the quantization table) If bit allocation b = 2, the quantized representative value q _s (s = 1,..., B ² ) of ⁴ ) is compared, and the quantized representative value q _s having the smallest difference is associated with the pixel. The quantized representative value q _s is determined, and the quantized representative value q _s is replaced with the quantized code Q _s . The replacement of the quantized representative value q _s and the quantized code Q _s is as follows when the bit allocation b = 2, for example.
q ₁ → Q ₁ = 0
q ₂ → Q ₂ = 1
q ₃ → Q ₃ = 2
q ₄ → Q ₄ = 3

In this way, after obtaining the quantization code corresponding to each pixel included in the three-dimensional block, the block encoding unit 65 obtains the quantization table corresponding to each block group, and the pixel value associated with each three-dimensional block. Encoded image data V _cd consisting of the minimum value, dynamic range, and quantization code is output to the _subsequent stage. Thereafter, the encoded digital image data V _cd is recorded on the recording medium 17 by the recording unit 44 or decoded by the decoding unit 31-2. The description of the first operation of the encoding unit 22 ends here.

  Next, the decoding unit 31 that performs decoding for encoding the encoding result by the encoding unit 22 will be described. FIG. 11 shows a configuration example of the decoding unit 31. The decoding unit 31 includes an encoded data separation unit 71 and a block decoding unit 72.

The encoded data separation unit 71 separates the quantization table corresponding to each block group included in the encoded digital image data V _cd input from the previous stage and supplies the separated quantization table to the encoded data separation unit 71. The encoded data separation unit 71 also performs block decoding on the maximum value, minimum value, dynamic range, quantization code, and the like related to each three-dimensional block included in the encoded digital image data V _cd input from the previous stage. To the conversion unit 72. The block decoding unit 72 performs block decoding (inverse ADRC) on each three-dimensional block using a corresponding quantization table.

  The encoding unit 22 performs a first operation (encoding process) corresponding to the first operation (encoding process) of the encoding unit 22 described above, or a second operation (encoding process) of the encoding unit 22 described later. The second operation (encoding process) corresponding to the process is executed.

The first operation (decoding process) of the decoding unit 31 corresponding to the first operation (encoding process) of the encoding unit 22 is illustrated by taking the decoding unit 31-2 of the encoding device 16 as an example. This will be described with reference to the flowchart of FIG. The encoding unit 31-2 is supplied with encoded digital image data V _cd (or encoded digital image data V _rd read from the recording medium 17 by the recording unit 44) from the encoding unit 22-2. To do.

In step S <b> 11, the encoded data separation unit 71 acquires a plurality of quantization tables corresponding to each block group from the encoded digital image data V _cd input from the previous stage and supplies the acquired quantization tables to the block decoding unit 72.

In step S12, the encoded data separation unit 71 inputs the minimum value min _{i of} the three-dimensional block (denoted as the three-dimensional block i) to be decoded, the dynamic range dr from the encoded digital image data V _cd input from the previous stage. _i and the quantized code Q _s are separated and output to the block decoding unit 92.

In step S13, the block decoding unit 92 performs block decoding (inverse ADRC) on the three-dimensional block to be decoded using the corresponding quantization table, and the digital image signal V _dg2 as a decoding result is _obtained . Output to the subsequent stage.

Specifically, based on the input dynamic range dr _i , the block group to which the three-dimensional block to be decoded belongs is specified, and the quantization table corresponding to the specified block group is supplied in step S11. Detect from a plurality of quantization tables. Then, by referring to the detected quantization table, a quantized representative value q _s corresponding to the quantum code Q _s of each pixel input from the encoded data separation unit 71 is acquired, and the following equation (5) is obtained. As shown, the minimum value min _i is added to the quantized representative value q _s to decode the pixel value L ′ _k of the pixel.
L ′ _k = q _s + min _i (5)

Since the digital image signal V _dg2 obtained in this way is the above-mentioned “second encoded / decoded image” and has deteriorated image quality, the analog image signal V _an1 is used by using the encoding device 16. Trying to copy is suppressed.

Next, the second operation (encoding process) of the encoding unit 22 will be described with reference to the flowchart of FIG. 13 using the encoding unit 22-2 of the encoding device 16 as an example.

First, as step S21, noise is added to the analog image signal _Van1 before being digitized by the noise adding unit 42 of the analog-digital converting unit 41. However, the process of step S21 may be omitted.

In step S22, the block division unit 61 converts the digital image signal V _dg1 (with noise added) input from the analog-digital conversion unit 41 into bx (pixel) × by (pixel) as shown in FIG. The data is divided into three-dimensional blocks of xbt (number of images) and output to the feature amount detection unit 62. Therefore, each three-dimensional block includes pixels included in a two-dimensional area common to each of the consecutive bt images. Note that bx, by, and bt can be set arbitrarily.

  In step S23, the feature amount detection unit 62 detects the maximum value max and the minimum value min of the pixel values of the pixels belonging to each three-dimensional block as the feature amount of each three-dimensional block divided in the process of step S22.

In step S24, the block group classification unit 63 classifies each three-dimensional block into a block group having a common maximum value and minimum value, as shown in FIG. For example, when the maximum value of a certain three-dimensional block is max _i and the minimum value is min _i , the three-dimensional block is classified into max _i and min _i group groups. Note that since the three-dimensional blocks classified into the same dynamic range block group have the same maximum value and minimum value, the dynamic range block that is the difference between the maximum value and the minimum value is also common.

  In step S25, the quantization table creation unit 64 creates a quantization table including a plurality of quantization representative values for each block group into which the three-dimensional block is classified.

Specifically, first, as shown in FIG. 15A, included in the max _i, if g pieces of three-dimensional block in min _i group set is classified, the three-dimensional block j, which is classified into the group group And m (= bx × by × bt) pixel values L _{ij, k} (j = 1, 2,..., G) (k = 1, 2,..., M) The difference value D _{ij, k} of the minimum value min _i is calculated. The difference value D _{ij, k} is 0 to dr _i (= max _i −min _i ).
D _{ij, k} = L _{ij, k} −min _i (6)

As a result, g × m calculation results are obtained, and the frequency distribution of the difference values D _{i, w} (w = 0,..., Dr _i ) is obtained as shown in FIG. 15B. The frequency D _{i, wd} of the difference value D _{i, w} (w = 0,..., Dr _i ) is assumed.

Next max _i, the total number of pixels included in the classified g pieces of three-dimensional block in min _i group set the ^{(m × g), 2 b} (b is bit allocation) calculating a value n _d obtained by equally dividing by To do.
n _d = (m × g) / 2 ^b (7)

Then, the quantization width Δ _p (p = 1,..., Bm (= b ² )) is sequentially determined according to the following rules.
When n _d = ΣD _{i, wd} (Σ is the sum of wd = 0,..., w ₁ ), Δ ₁ = w ₁
When n _d = ΣD _{i, wd} (Σ is the sum of wd = w ₁ +1,..., w ₂ ), Δ ₂ = w ₂ −w ₁
...
When n _d = ΣD _{i, wd} (Σ is the sum of wd = w _bm−1 +1,..., w _bm ), Δ _bm = w _bm −w _bm−1

For example, when quantization is performed with bit allocation b = 2, the quantization width is determined so that the areas of the frequency distribution (A, B, C, D in FIG. 15B) are equal as shown in FIG. 15B. Will be.
Δ ₁ = w ₁
Δ ₂ = w ₂ −w ₁
Δ ₃ = w ₃ −w ₂
Δ ₄ = w ₄ −w ₃

After determining the quantization width _Δp in this way, a plurality of quantization representative values are determined. As described above with reference to FIG. 10A, the quantization representative value is determined by the first determination method in which the middle of each quantization width Δ _p is set as the quantization representative value, or described above with reference to FIG. 10B. As described above, the second determination method for determining the boundary of each quantization width _Δp as the quantization representative value is adopted.

When the first determination method is adopted, the quantization representative value q _s (s = 1,..., B ² ) is as follows by taking the case of quantization with bit allocation b = 2 as an example.
q ₁ = w _1/2
q ₂ = w ₁ + (w ₂ −w ₁ ) / 2
q ₃ = w ₂ + (w ₃ −w ₂ ) / 2
q ₄ = w ₃ + (w ₄ −w ₃ ) / 2

When the second determination method is adopted, n _d is calculated using the following equation (8) instead of equation (7).
n _d = (m × g) / (2 ^b −1) (8)
Taking the case of quantization with bit allocation b = 2 as an example, the representative quantization value q _s (s = 1,..., B ² ) is as follows.
q ₁ = 0
q ₂ = w ₁
q ₃ = w ₂
q ₄ = w ₃

As described above, the plurality of quantized representative values q _s calculated for each block group, that is, the quantization table, is used in the subsequent quantization unit 65.

Returning to FIG. In step S26, the quantization unit 65 quantizes each three-dimensional block. Specifically, a quantization table corresponding to a block group to which a three-dimensional block to be quantized belongs is obtained, and a pixel value of each pixel included in the three-dimensional block and a plurality of (for example, the quantization table) If bit allocation b = 2, the quantized representative value q _s (s = 1,..., B ² ) of ⁴ ) is compared, and the quantized representative value q _s having the smallest difference is associated with the pixel. The quantized representative value q _s is determined, and the quantized representative value q _s is replaced with the quantized code Q _s . The replacement of the quantized representative value q _s and the quantized code Q _s is as follows when the bit allocation b = 2, for example.
q ₁ → Q ₁ = 0
q ₂ → Q ₂ = 1
q ₃ → Q ₃ = 2
q ₄ → Q ₄ = 3

In this way, after obtaining the quantization code corresponding to each pixel included in the three-dimensional block, the block encoding unit 65 obtains the quantization table corresponding to each block group, and the pixel value associated with each three-dimensional block. The encoded image data V _cd consisting of the maximum and minimum values and the quantization code are output to the _subsequent stage. Thereafter, the encoded digital image data V _cd is recorded on the recording medium 17 by the recording unit 44 or decoded by the decoding unit 31-2. This is the end of the description of the second operation of the encoding unit 22.

Next, for the second operation (decoding process) of the decoding unit 31 corresponding to the second operation (encoding process) of the encoding unit 22, the decoding unit 31-2 of the encoding device 16 is taken as an example. Next, a description will be given with reference to the flowchart of FIG. The encoding unit 31-2 is supplied with encoded digital image data V _cd (or encoded digital image data V _rd read from the recording medium 17 by the recording unit 44) from the encoding unit 22-2. To do.

In step S <b> 31, the encoded data separation unit 71 acquires a plurality of quantization tables corresponding to each block group from the encoded digital image data V _cd input from the previous stage and supplies the acquired quantization tables to the block decoding unit 72.

In step S32, the maximum value mix _i and minimum value min of the three-dimensional block (denoted as three-dimensional block i) to be decoded from the encoded digital image data V _cd input from the preceding stage by the encoded data separation unit 71. _i and the quantized code Q _s are separated and output to the block decoding unit 92.

In step S33, the block decoding unit 92 performs block decoding (inverse ADRC) on the three-dimensional block to be decoded using the corresponding quantization table, and _obtains a digital image signal V _dg2 as a decoding result. Output to the subsequent stage.

Specifically, the block group to which the three-dimensional block to be decoded belongs is specified based on the input maximum value mix _i and minimum value min _i , and the quantization table corresponding to the specified block group is Detection is performed from the plurality of quantization tables supplied in S31. Then, by referring to the detected quantization table, a quantized representative value q _s corresponding to the quantum code Q _s of each pixel input from the encoded data separation unit 71 is acquired, and the following equation (9) is obtained. As shown, the minimum value min _i is added to the quantized representative value q _s to decode the pixel value L ′ _k of the pixel.
L ′ _k = q _s + min _i (9)

Since the digital image signal V _dg2 obtained in this way is the above-mentioned “second encoded / decoded image” and has deteriorated image quality, the analog image signal V _an1 is used by using the encoding device 16. Trying to copy is suppressed.

Here, the digital image signal V _dg2 output from the decoding unit 31-2 (second encoding and decoding images), a digital image signal V _dg1 (1 st output from the decoding unit 31-1 The fact that the image quality is deteriorated compared to the encoded / decoded image will be described.

  FIG. 17 shows the second encoding (the above-described first or second encoding process) / decoding (the above-described first or second decoding process corresponding to the first or second encoding process). Shows an outline when the image quality deteriorates.

  When the original image is divided into three-dimensional blocks, it is assumed that the lower-left three-dimensional block of the original image is classified into the same block group as a plurality of other three-dimensional blocks as shown in FIG. For this block group, a quantization table including a plurality of quantization representative values as shown in FIG. Therefore, assuming that the pixel values of the pixels included in the lower left three-dimensional block of the original image are as shown in FIG. C, “the signal after the first encoding / decoding” is shown in FIG. As shown. This is a state in which the pixel value of each pixel is replaced with the quantized representative value, but shows a value relatively close to the original signal shown in FIG.

  When noise (white noise, phase shift, etc.) occurs in the “signal after the first encoding / decoding”, the maximum value and the minimum value of the pixel value may change. For example, noise is generated in the “signal after the first encoding / decoding”, and “distortion added to the signal after the first encoding / decoding” as shown in FIG. When the pixel value changes, as shown in Fig. E, the three-dimensional block at the lower left of the original image of interest is classified into the same block group as other three-dimensional blocks different from the previous one (Fig. A). become. For this block group, a quantization table including quantization representative values as shown in FIG. “Signals after second encoding / decoding” are as shown in FIG.

  The quantization table used in the second time (F in the figure) is different from the quantization table (B in the same figure) used in the first time. In the first place, the quantization table is a three-dimensional block classified into a block group having a common dynamic range in the first encoding process and a block group having a common maximum value and minimum value in the second encoding process. This is obtained from the frequency distribution of the pixels included in the block. In addition, the decoding result of encoding / decoding using the quantization table becomes a quantization representative value.

  Since the quantization table used at the first time is created on the basis of the original signal, the decoding result of encoding / decoding becomes a quantization representative value but a value close to the original signal.

  However, the quantization table used at the second time is created based on a state in which no value of the original signal remains, that is, a state in which the pixel values of all the pixels are replaced with quantized representative values. The second decoding result is far away from the original signal and causes image degradation. Further, since the quantization table is created for a block group composed of a plurality of three-dimensional blocks, the image is degraded over a wide range.

As described above, the analog image signal V _an1 output from the playback device 14 has noise (distortion with a high-frequency component added) due to the characteristics at the time of digital-analog conversion, and this is displayed on the display 15. Sometimes there is no effect on image quality.

However, when the analog image signal V _an1 output from the reproduction device 14 is encoded again by the encoding device 16, it is encoded so that the image quality is degraded at the time of decoding. This is not suitable for copying image signals.

In addition, with the knowledge that the reproduction result is deteriorated, the recording medium 17 on which the encoded digital image data V _cd is recorded by the encoding device 16 is reproduced by the reproduction device 14 or the like, and the reproduction result is encoded. In the case of re-encoding by 16, the image quality is further deteriorated at the time of decoding. Therefore, the encoding device 16 is not suitable for the second and subsequent copying of the analog image signal. Therefore, copying of analog data using the encoding device 16 is suppressed.

  By the way, the series of processes described above can be executed by hardware, but can also be executed by software. When a series of processing is executed by software, a program constituting the software may execute various functions by installing a computer incorporated in dedicated hardware or various programs. For example, a general-purpose personal computer configured as shown in FIG. 18 is installed from the recording medium.

  The personal computer 100 includes a CPU (Central Processing Unit) 101. An input / output interface 105 is connected to the CPU 101 via the bus 104. A ROM (Read Only Memory) 102 and a RAM (Random Access Memory) 103 are connected to the bus 104.

  The input / output interface 105 stores an input unit 106 including an input device such as a keyboard and a mouse for a user to input an operation command, an output unit 107 including a display for displaying a processing result image, and the like, and programs and various data. A storage unit 108 including a hard disk drive and a communication unit 109 that includes a modem, a LAN (Local Area Network) adapter, and the like and executes communication processing via a network represented by the Internet are connected. In addition, a drive 110 for reading / writing data from / to a recording medium 111 such as a magnetic disk (including a flexible disk), an optical disk (including a CD-ROM, a DVD), a magneto-optical disk (including an MD), or a semiconductor memory is connected. Has been.

  A program for causing the personal computer 100 to execute the above-described series of processing is supplied to the personal computer 100 while being stored in the recording medium 111, read by the drive 110, and installed in a hard disk drive built in the storage unit 108. Has been. The program installed in the storage unit 108 is loaded from the storage unit 108 to the RAM 103 and executed in response to a command from the CPU 101 corresponding to a command from the user input to the input unit 106.

  In this specification, the steps executed based on the program are executed in parallel or individually even if they are not necessarily processed in time series, as well as processes executed in time series according to the described order. It also includes processing.

  The program may be processed by a single computer, or may be distributedly processed by a plurality of computers. Furthermore, the program may be transferred to a remote computer and executed.

  Further, in this specification, the system represents the entire apparatus constituted by a plurality of apparatuses.

It is a block diagram which shows the structural example of the image display system to which this invention is applied. It is a figure for demonstrating white noise. It is a figure for demonstrating phase shift. It is a figure for demonstrating the operation | movement outline | summary of an image display system. It is a block diagram which shows the structural example of the encoding part in FIG. 6 is a flowchart illustrating a first operation of the encoding unit shown in FIG. 5. It is a figure for demonstrating the process of step S2 of FIG. It is a figure for demonstrating the process of step S4 of FIG. It is a figure for demonstrating the process of step S5 of FIG. It is a figure for demonstrating the process of step S5 of FIG. It is a block diagram which shows the structural example of the decoding part in FIG. 12 is a flowchart for explaining a first operation of the decoding unit shown in FIG. 11. 6 is a flowchart for explaining a second operation of the encoding unit shown in FIG. 5. It is a figure for demonstrating the process of step S24 of FIG. It is a figure for demonstrating the process of step S25 of FIG. 12 is a flowchart for explaining a second operation of the decoding unit shown in FIG. 11. It is a figure for demonstrating the effect by the 1st or 2nd encoding process by an encoding part. It is a block diagram which shows the structural example of the personal computer to which this invention is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Image display system, 12 encoding apparatus, 14 reproduction | regeneration apparatus, 16 encoding apparatus, 22 encoding part, 31 decoding part, 32 digital analog conversion part, 41 analog digital conversion part, 42 noise addition part, 61 block division part , 62 feature quantity detection unit, 63 block group classification unit, 64 quantization table creation unit, 65 quantization unit, 71 encoded data separation unit, 72 block decoding unit, 100 personal computer, 101 CPU, 111 recording medium

Claims (37)

In an encoding device for encoding input image data,
Blocking means for blocking the image data into blocks of a predetermined size;
Detecting means for detecting a feature quantity of image data in each block blocked by the blocking means;
Block group generation means for grouping each block blocked by the blocking means based on the feature amount detected by the detection means to generate a block group;
For each block group generated by the block group generation means, a creation means for creating a quantization table composed of a plurality of quantization representative values based on the frequency distribution of image data in the block belonging to the block group;
An encoding apparatus comprising: quantization means for quantizing the image data of each block blocked by the blocking means based on the quantization table corresponding to the block group to which the block belongs. The encoding apparatus according to claim 1, wherein noise is added to the image data. The encoding apparatus according to claim 1, further comprising noise adding means for adding noise to the inputted image data. The encoding apparatus according to claim 1, wherein the image data is encoded at least once and then decoded. The encoding device according to claim 1, wherein the blocking unit blocks a plurality of pieces of image data into a three-dimensional block. For each block group generated by the block group generation unit, the creation unit is configured to quantize pixels included in the block group based on a frequency distribution of image data in the block belonging to the block group. The encoding apparatus according to claim 1, wherein the quantization table is created by determining the plurality of quantization representative values so as to be evenly distributed to the representative values. The encoding device according to claim 1, wherein the detection unit detects at least a minimum value and a dynamic range of a pixel value included in each block blocked by the blocking unit. The encoding apparatus according to claim 7, wherein the block group generation unit generates a block group by grouping blocks having a common dynamic range of pixel values detected by the detection unit. The creating means is based on a frequency distribution of a difference value between a pixel value of each pixel of each block belonging to the block group and a minimum value of the pixel of the block for each block group generated by the block group generating means. The encoding apparatus according to claim 7, wherein a quantization table including a plurality of quantization representative values is created. The encoding apparatus according to claim 1, wherein the quantization means outputs at least the quantization table and a quantization code that is a quantization result of the image data of each block. The encoding device according to claim 1, wherein the detection unit detects at least a maximum value and a minimum value of pixel values of pixels included in each block blocked by the blocking unit. 12. The encoding apparatus according to claim 11, wherein the block group generation unit generates a block group by grouping blocks having a common maximum value and minimum value of pixel values detected by the detection unit. . The creation means, for each block group generated by the block group generation means, a frequency of a difference value between a pixel value of each pixel of each block belonging to the block group and a minimum pixel value common to the block group The encoding apparatus according to claim 11, wherein a quantization table including a plurality of quantization representative values is created based on the distribution. The encoding apparatus according to claim 1, further comprising an inverse quantization unit that inversely quantizes an output result of the quantization unit. In an encoding method for encoding input image data,
A blocking step of blocking the image data into blocks of a predetermined size;
A detecting step of detecting a feature amount of image data in each block blocked by the processing of the blocking step;
A block group generation step for generating a block group by grouping each block that has been blocked by the process of the blocking step based on the feature amount detected by the process of the detection step;
A creation step for creating a quantization table including a plurality of quantization representative values for each block group generated by the processing of the block group generation step, based on a frequency distribution of image data in the block belonging to the block group When,
An encoding method, comprising: a quantization step of quantizing the image data of each block that has been blocked in the processing of the blocking step based on the quantization table corresponding to the block group to which the block belongs. The encoding method according to claim 15, wherein noise is added to the image data. The encoding method according to claim 15, further comprising a noise adding step of adding noise to the input image data. The encoding method according to claim 15, wherein the image data is encoded at least once and then decoded. The encoding method according to claim 15, wherein the blocking step blocks a plurality of pieces of image data into three-dimensional blocks. In the creation step, for each block group generated by the processing of the block group generation step, pixels included in the block group are based on the frequency distribution of image data in the block belonging to the block group. The encoding method according to claim 15, wherein the quantization table is created by determining the plurality of quantization representative values so as to be evenly distributed to the quantization representative values. The encoding method according to claim 15, wherein the detecting step detects at least a minimum value and a dynamic range of a pixel value included in each block that is blocked by the processing of the blocking step. The encoding method according to claim 21, wherein in the block group generation step, blocks having a common dynamic range of pixel values detected in the detection step are grouped to generate a block group. In the creation step, for each block group generated by the processing of the block group generation step, a frequency distribution of a difference value between a pixel value of each pixel of each block belonging to the block group and a minimum value of the pixel of the block The encoding method according to claim 21, wherein a quantization table including a plurality of quantization representative values is created based on the method. The encoding method according to claim 21, wherein the quantization step outputs at least the quantization table and a quantization code that is a quantization result of the image data of each block. The encoding method according to claim 15, wherein the detecting step detects at least a maximum value and a minimum value of pixel values of pixels included in each of the blocks that are blocked by the processing of the blocking step. The code according to claim 25, wherein the block group generation step generates a block group by grouping blocks having the same maximum and minimum pixel values detected in the processing of the detection step. Method. In the creation step, for each block group generated in the block group generation step, a difference value between a pixel value of each pixel of each block belonging to the block group and a minimum value of pixels common to the block group The encoding method according to claim 25, wherein a quantization table including a plurality of quantization representative values is created based on the frequency distribution. A program for encoding input image data,
A blocking step of blocking the image data into blocks of a predetermined size;
A detecting step of detecting a feature amount of image data in each block blocked by the processing of the blocking step;
A block group generation step for generating a block group by grouping each block that has been blocked by the process of the blocking step based on the feature amount detected by the process of the detection step;
A creation step for creating a quantization table including a plurality of quantization representative values for each block group generated by the processing of the block group generation step, based on a frequency distribution of image data in the block belonging to the block group When,
And a quantization step for quantizing the image data of each block that has been blocked in the blockization step processing based on the quantization table corresponding to the block group to which the block belongs. Medium on which various programs are recorded. A program for encoding input image data,
A blocking step of blocking the image data into blocks of a predetermined size;
A detecting step of detecting a feature amount of image data in each block blocked by the processing of the blocking step;
A block group generation step for generating a block group by grouping each block that has been blocked by the process of the blocking step based on the feature amount detected by the process of the detection step;
A creation step for creating a quantization table including a plurality of quantization representative values for each block group generated by the processing of the block group generation step, based on a frequency distribution of image data in the block belonging to the block group When,
And a quantization step of quantizing the image data of each block that has been blocked in the blockization step processing based on the quantization table corresponding to the block group to which the block belongs. Program. An image that includes an encoding unit that encodes image data and a decoding unit that decodes the output of the encoding unit, and the image data is deteriorated when encoding and decoding are repeated on the image data In the processing system,
The encoding unit includes:
Blocking means for blocking the image data into blocks of a predetermined size;
Detecting means for detecting a feature quantity of image data in each block blocked by the blocking means;
Block group generation means for grouping each block blocked by the blocking means based on the feature amount detected by the detection means to generate a block group;
For each block group generated by the block group generation means, a creation means for creating a quantization table composed of a plurality of quantization representative values based on the frequency distribution of image data in the block belonging to the block group;
An image processing system comprising: quantization means for quantizing image data of each block blocked by the blocking means based on the quantization table corresponding to the block group to which the block belongs. The image processing system according to claim 30, further comprising: a noise adding unit that adds noise to image data that is a decoding result of the decoding unit and supplies the image data to the encoding unit. An image that includes an encoding unit that encodes image data and a decoding unit that decodes the output of the encoding unit, and the image data is deteriorated when encoding and decoding are repeated on the image data In the image processing method of the processing system,
In the encoding unit,
A blocking step of blocking the image data into blocks of a predetermined size;
A detecting step of detecting a feature amount of image data in each block blocked by the processing of the blocking step;
A block group generation step for generating a block group by grouping each block that has been blocked by the process of the blocking step based on the feature amount detected by the process of the detection step;
A creation step for creating a quantization table including a plurality of quantization representative values for each block group generated by the processing of the block group generation step, based on a frequency distribution of image data in the block belonging to the block group When,
An image processing method comprising: a quantization step of quantizing the image data of each block that has been blocked by the processing of the blocking step based on the quantization table corresponding to the block group to which the block belongs. The image processing system further includes a noise adding unit that adds noise to image data and supplies the image data to the encoding unit,
In the noise adding unit,
The image processing method according to claim 32, further comprising a noise addition step of adding noise to the image data that is a decoding result of the decoding unit and supplying the image data to the encoding unit. An image that includes an encoding unit that encodes image data and a decoding unit that decodes the output of the encoding unit, and the image data is deteriorated when encoding and decoding are repeated on the image data In the processing system,
The decoding unit
Detection means for detecting at least a quantization table and a quantization code from the encoded data that is a result of the image data being blocked into predetermined blocks by the encoding unit and encoded in units of blocks;
An image processing system comprising: decoding means for decoding the block-unit image data from the quantization code by referring to the quantization table. 35. The image processing system according to claim 34, further comprising a noise adding unit that adds noise to image data that is a decoding result of the decoding unit and supplies the image data to the encoding unit. An image that includes an encoding unit that encodes image data and a decoding unit that decodes the output of the encoding unit, and the image data is deteriorated when encoding and decoding are repeated on the image data In the image processing method of the processing system,
In the decoding unit,
A detection step of detecting at least a quantization table and a quantization code from encoded data that is a result of the image data being blocked into predetermined blocks by the encoding unit and encoded in units of blocks;
A decoding step of decoding the block-unit image data from the quantization code by referring to the quantization table. The image processing system further includes a noise adding unit that adds noise to image data and supplies the image data to the encoding unit,
In the noise adding unit,
37. The image processing method according to claim 36, further comprising a noise addition step of adding noise to image data that is a decoding result of the decoding unit and supplying the image data to the encoding unit.

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