JP2005191895A - Video signal processor, video signal processing method and video signal processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To emphasize the high band components of input video signals without emphasizing ringing and mosquito noise. <P>SOLUTION: A video signal processor is provided with a high band emphasis means 20 for emphasizing the high band components of the input video signals and a non-emphasis area / non-emphasis amount detection means 30 for obtaining detection output α corresponding to non-emphasis areas before and after the edge part of the input video signals and a non-emphasis amount from the input video signals. The emphasis amount of the high band components in the high band emphasis means 20 is controlled corresponding to the detection output α of the non-emphasis area / non-emphasis amount detection means 30. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a video signal processing device, a video signal processing method, and a video signal processing program for performing high frequency enhancement processing (enhancement processing) such as edge enhancement on a video signal.

  Conventionally, high-frequency emphasis processing (enhancement processing) is performed, for example, by performing edge emphasis on a video signal obtained by, for example, a television receiver and obtained by video detection, so that the contour of the displayed video is clear. ) Has been carried out.

  For example, Patent Document 1 (Japanese Patent Laid-Open No. 11-112838) discloses that the enhancement processing is controlled according to the noise level of the video signal so that the enhancement processing is not performed in a place where there is a lot of noise. Alternatively, it is described that the flicker accompanying the fluctuation of the noise level for each frame can be reduced.

The above-mentioned patent documents are as follows.
JP-A-11-112838

  By the way, a video signal such as an NTSC (National Television System Committee) signal received by a television receiver and subjected to video detection has a steep filter characteristic for removing an audio signal component, for example. For this reason, as shown in FIG. 15, when a lot of ringing 2 occurs before and after the edge portion 1 which is a high frequency component of the video signal, and the front and back of the edge portion 1 are flat as shown in FIG. The ringing is noticeable on the screen and causes image quality to deteriorate.

  When an enhancement process is performed on a video signal in which such ringing has occurred, there is a problem that not only the edge portion is emphasized but also the ringing is emphasized.

  Further, when the image is compressed by MPEG (Moving Picture Experts Group), for example, the noise is called mosquito noise in a flat portion near a large amplitude signal due to loss of signal components. For the same reason, there is a problem that when the video signal is subjected to enhancement processing, mosquito noise is also emphasized.

  In view of the above problems, the present invention performs enhancement processing without emphasizing such noise even if there is noise such as ringing or mosquito noise in the vicinity of the edge portion of the video signal. An object is to provide a video signal processing apparatus, a video signal processing method, and a video signal processing program that can be emphasized.

In order to solve the above problems, in the invention of claim 1,
High frequency enhancement means for enhancing high frequency components of the input video signal;
A non-enhanced region / non-enhanced amount detecting means for obtaining a detection output corresponding to a non-emphasized region before and after an edge portion of the input video signal and a non-enhanced amount from the input video signal;
And an enhancement amount of the high frequency component in the high frequency enhancement means is controlled in accordance with the detection output of the non-emphasis region / non-emphasis amount detection means.

  According to the first aspect of the present invention, the non-emphasized region / non-emphasized amount detecting means detects the region before and after the edge portion, which is a high frequency component of the input video signal, as the non-emphasized region. Then, in the detected non-emphasized area, the high-frequency emphasis amount in the high-frequency emphasizing means is controlled by the detection output of the non-emphasized area / non-emphasized amount detecting means so that the high-frequency emphasis is not so much emphasized.

  Therefore, according to the first aspect of the present invention, even if ringing or mosquito noise is on the detected non-emphasized area as described above, the ringing or mosquito noise is not emphasized and only the edge portion is included. Is emphasized.

  According to the present invention, even if ringing or mosquito noise is on the edge portion of the input video signal, the ringing or mosquito noise is not emphasized, and only the high frequency component such as the edge portion is enhanced. it can.

  Embodiments of a video signal processing apparatus and method according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing the overall configuration of the video signal processing apparatus according to the embodiment. In this example, only the edge portion is emphasized without emphasizing ringing existing before and after the edge portion of the input video signal. It is an example when it is made possible to do.

  The input video signal Vi is supplied to the high frequency emphasis circuit (enhancer) 20 through the input terminal 11 and is also supplied to the non-emphasis region / non-emphasis amount detection circuit 30.

  The non-emphasized region / non-emphasized amount detection circuit 30 detects an edge portion of the input video signal Vi and, as will be described later in detail, wants to emphasize a predetermined flat region before and after the detected edge portion by high-frequency emphasis. A non-enhanced region is output, and a detection output α corresponding to the non-enhancement amount detected based on the detected edge portion is output. That is, as shown in FIG. 15, the non-emphasized region / non-emphasized amount detection circuit 30 sets a section in which ringing before and after the edge portion may exist as a non-emphasized region, It is estimated that ringing corresponding to the size of the portion will occur, and a detection output α (α ≦ 1) is generated and output so as to have a non-enhancement amount corresponding to the size of the edge portion.

  The high frequency emphasis circuit 20 includes a high pass filter 21, a non-linear conversion circuit 22, an output control circuit 23, and an adder circuit 24. The high pass filter 21 extracts the high frequency component VHi from the input video signal Vi.

  The non-linear conversion circuit 22 is for enhancing the high-frequency component more, and the input / output characteristics thereof have non-linear characteristics as shown in FIG. That is, the nonlinear characteristic of the nonlinear conversion circuit 22 is that when the input level (absolute value) of the high frequency component VHi of the input video signal is very small, the output level is zero, and when the input level becomes equal to or higher than the first predetermined level L1, The output level is set to be constant when the output level is higher than the level and becomes equal to or higher than the second predetermined level L2.

  In this example, the high frequency component CVHi of the input video signal obtained from the nonlinear conversion circuit 22 is supplied to the addition circuit 24 through the output control circuit 23 and added to the input video signal Vi input through the input terminal 11. .

The output control circuit 23 adds the high frequency component CVHi of the input video signal from the nonlinear conversion circuit 22 to the input video signal Vi by the addition circuit 24 in accordance with the detection output α of the non-emphasized region / non-emphasized amount detection circuit 30. The amount of signal to be controlled is controlled. From the output control circuit 23,
EVHi = CVHi × (1-α)
An output signal EVHi is obtained.

  In this case, the larger the detection output α, the smaller the addition amount of the signal from the nonlinear conversion circuit 22 in the addition circuit 24. The smaller the detection output α, the addition of the signal from the nonlinear conversion circuit 22 in the addition circuit 24. The amount is large.

That is, in the adding circuit 24,
Vi + CVHi × (1-α)
Is calculated. In this case, as the amount of addition of the signal from the nonlinear conversion circuit 22 increases in the adding circuit 24, the amount of high frequency emphasis increases. Therefore, the magnitude of the detection output α is an amount that does not emphasize high frequency, that is, non-emphasized. It depends on the amount.

  In this embodiment, an output video signal Vo is obtained as an output of the adder circuit 24 and is output to the next stage through the output terminal 12.

  The video signal processing apparatus according to this embodiment has the above-described configuration, and the high frequency component of the input video signal Vi is added to the input video signal Vi to enhance the high frequency. In the section where the ringing before and after the edge portion of the input video signal Vi is easy to ride due to the detection output α from the enhancement amount detection circuit 30, the high-frequency enhancement amount is small or high-frequency enhancement is not performed. Even if ringing occurs in the section before and after the part, the ringing is prevented from being emphasized, and image degradation can be suppressed.

  Although the configuration of FIG. 1 can be configured as an analog circuit, in this embodiment, the configuration is configured as a digital circuit. Therefore, the input video signal Vi is a digital video signal with a sampling frequency of, for example, 13.5 MHz, and the high-pass filter 21 is a high-pass filter using a digital filter. In this case, as the digital filter, either an FIR (Finite Impulse Response) type or an IIR (Infinite Impulse Response) type can be used.

  FIG. 3 shows an example of the configuration of an FIR type digital filter. A plurality of one-sample delay circuits 41 connected in series with an input signal, and coefficients are applied to the input signal and the output signal of each delay circuit 41. A plurality of coefficient multiplying circuits 42 to be multiplied and a sum calculating circuit 43 for calculating the sum of the outputs of the plurality of coefficient multiplying circuits 42 are output from the sum calculating circuit 43.

  This digital filter has filter coefficients W0, W1, W2... W (n−2), W (n−1) multiplied by the number of taps (number of delay circuits 41 + 1) and a plurality of coefficient multiplication circuits 42. ) (N is the number of taps), a filter having a desired characteristic can be configured. In this example, the high-pass filter 21 is, for example, a 3-tap digital filter, and the filter coefficients W1 to W3 are configured as shown in FIG.

<Detailed Configuration Example of Non-emphasized Region / Non-emphasized Amount Detection Circuit 30>
Next, a detailed configuration example of the non-emphasized region / non-emphasized amount detection circuit 30 in this embodiment will be described. The non-enhanced region / non-enhanced amount detection circuit 30 of this embodiment determines how far the region from the edge portion is set as the non-enhanced region according to the occurrence of ringing that occurs in the target input video signal Vi. It has a configuration that can be easily set. For this reason, in this embodiment, for example, the state of occurrence of ringing that occurs in the target input video signal Vi is examined in advance, and how far away from the edge portion is determined as the non-emphasized region according to the state of occurrence. I am trying to decide.

  FIG. 5 is a block diagram showing a configuration example of the non-emphasized region / non-emphasized amount detection circuit 30 in this embodiment. 6 to 8 are diagrams for explaining a configuration example of the non-emphasized region / non-emphasized amount detection circuit 30 in this embodiment. Hereinafter, the configuration of the non-emphasized region / non-emphasized amount detection circuit 30 in this embodiment will be described with reference to FIGS.

  As shown in FIG. 5, in the non-emphasized region / non-emphasized amount detection circuit 30 in this embodiment, an input video signal (digital video signal) Vi is supplied to a high-pass filter 301 formed of a digital filter. In this example, the high-pass filter 301 is a 5-tap digital filter, and the filter coefficient is configured as shown in FIG. 6, for example.

  The output S1 of the high-pass filter 301 is supplied to the absolute value circuit 302 to be converted into an absolute value, and the absolute value output S2 is supplied to the nonlinear conversion circuits 303 and 304. These nonlinear conversion circuits 303 and 304, as will be described in detail later, ringing is conspicuous at the edge portion of the large amplitude and is not conspicuous at the edge portion of the medium amplitude and the small amplitude. It is provided in order to change the detection judgment as to whether or not the ringing occurs at the edge portion having a small amplitude.

  These non-linear circuits 303 and 304 are respectively supplied to low-pass filters 305 and 306 made of digital filters. In this example, the low-pass filters 305 and 306 are both 3-tap digital filters having filter coefficients as shown in FIG.

  The output S3 of the low-pass filter 305 is supplied to the non-emphasized area setting circuit 307. The non-emphasized region setting circuit 307 includes a plurality of delay circuits 308 to 312 for setting a non-emphasized region, amplifiers 313 to 316, and a maximum value detecting circuit 317.

  In the non-emphasized region setting circuit 307, the output S3 of the low-pass filter 305 is delayed by a predetermined delay amount DLc by the delay circuit 310. In this example, the output S4 of the delay circuit 310 is a signal at the sample position of interest. Then, the delay circuits 308 and 309 respectively delay the output S3 of the low-pass filter 305 by a different delay amount that is smaller than the delay amount DLc, and obtain signals S5 and S6 before the output S4 at the sample position of interest. .

  Further, the delay circuits 311 and 312 further delay the output S4 of the delay circuit 310, thereby delaying the output S3 of the low-pass filter 305 by a different delay amount, which is larger than the delay amount DLc, respectively. Signals S7 and S8 at a later time are obtained.

  In this embodiment, the delay amounts of the delay circuits 308 to 312 are set as follows, for example. That is, the delay amount DLc of the delay circuit 310 is 17 samples, the delay amount of the delay circuit 308 is 0 samples (no delay), and the delay amount of the delay circuit 309 is 8 samples. The delay amount of the delay circuit 311 is 9 samples, and the delay amount of the delay circuit 312 is 17 samples.

  Therefore, in this example, the output S4 of the delay circuit 310 and the output S5 of the delay circuit 308 are separated by 17 samples, and the output S4 of the delay circuit 310 and the output S6 of the delay circuit 309 are separated by 9 samples, respectively. Since the delay amount of the delay circuit 311 is 9 samples and the delay amount of the delay circuit 312 is 17 samples, the signals S5, S6, S7, and S8 are centered on the output S4 of the delay circuit 310. The signals are at different positions for the same time before and after.

  The outputs S5, S6 and S7, S8 of the delay circuits 308 and 309 and the delay circuits 311 and 312 are supplied to the maximum value detection circuit 317 through the amplifiers 313, 314, 315 and 316, respectively. The maximum value detection circuit 317 outputs the maximum value of the input signals S5, S6 and S7, S8 at each time point. The output S9 of the maximum value detection circuit 317 is supplied to the division circuit 318.

  The output of the low-pass filter 306 is supplied to the division circuit 318 through the delay circuit 319 having the same delay amount as that of the delay circuit 310 that obtains the output S4 of the sample position of interest. The delay circuit 319 is for synchronizing the output of the low-pass filter 306 with the sample position of interest.

  The division circuit 318 divides the output S9 of the maximum value detection circuit 317 by the output of the low-pass filter 306 through the delay circuit 319. Note that, in the division circuit 318, when the value of the output of the low-pass filter 306 through the delay circuit 319 is zero, the value of the output of the low-pass filter 306 is replaced with the minimum value that can be expressed, and division is performed.

  By the processing in the above-described nonlinear conversion circuits 303 and 304 and the division circuit 318, ringing is easily detected in the edge portion of the large amplitude where the ringing is conspicuous, and the edge of medium amplitude or small amplitude where the ringing is not so conspicuous In part, the detection sensitivity of ringing is lowered.

  In other words, in this embodiment, the nonlinear conversion circuit 303 has an input / output characteristic in the small amplitude and medium amplitude regions of the input signal as shown in FIG. Also, it is assumed that it has a non-linear characteristic lifted as shown by a solid line. That is, the nonlinear conversion circuit 303 outputs an output signal at a lower output level than the linear case when the input signal is equal to or lower than the predetermined level θ2, and the linear signal when the input signal is equal to or higher than the predetermined level θ2. The output signal is output at a higher output level.

  On the other hand, as shown in FIG. 8B, the nonlinear conversion circuit 304 has an input / output characteristic in a region of small amplitude and medium amplitude of the input signal as shown by a solid line rather than a linear shape as shown by a broken line. It has the nonlinear characteristics raised. That is, the non-linear conversion circuit 304 outputs an output signal at an output level larger than the linear case when the input signal is equal to or lower than the predetermined level θ2, and the linear signal when the input signal is equal to or higher than the predetermined level θ2. An output signal is output at a lower output level.

  In the division circuit 318, as described above, the output of the non-linear conversion circuit 303 passed through the low-pass filter 305 is divided by the output of the non-linear circuit 304 passed through the low-pass filter 306. The large amplitude portion is emphasized and easily detected as ringing, and the small amplitude portion is difficult to detect as ringing.

  This will be further described with reference to FIG. 9 and FIG.

  That is, as shown in FIG. 9 (A), when the signal has a large amplitude, the ringing is large, while when the signal has a medium amplitude and a small amplitude as shown in FIG. 9 (B). Even if ringing or a signal resembling ringing occurs in the edge portion, it becomes small and is not noticeable on the display image.

  When a circuit having a linear input / output characteristic is provided instead of the non-linear conversion circuits 303 and 304, the division circuit 318 outputs a detection output regardless of whether the signal has a large amplitude or a medium amplitude or a small amplitude. The value will be similar.

  On the other hand, when the nonlinear conversion circuits 303 and 304 whose input / output characteristics are nonlinear are provided, when the signal has a large amplitude, the nonlinear conversion circuit 303 outputs the signal with a larger amplitude. In the non-linear conversion circuit 304, the output is output as the amplitude is reduced. In the division circuit 318, the signal on the non-linear conversion circuit 303 side becomes a numerator and the signal on the non-linear conversion circuit 304 side becomes a denominator, so that the division result is more emphasized as shown in FIG. Detected.

  Further, in the case where the nonlinear conversion circuits 303 and 304 whose input / output characteristics are nonlinear are provided, when the signal has medium amplitude and small amplitude, the nonlinear conversion circuit 303 outputs the signal with smaller amplitude, The nonlinear conversion circuit 304 outputs a larger amplitude. Therefore, the division result in the division circuit 318 is detected as being smaller as shown in FIG.

  Therefore, the ringing in the large amplitude portion is more easily detected, and the detection sensitivity of the ringing is lowered in the medium amplitude portion and the small amplitude portion.

  The output of the division circuit 318 is supplied to a non-linear conversion circuit 320 for generating a detection output value α corresponding to the period and amount of reduction of ringing. The nonlinear conversion circuit 320 has input / output nonlinear characteristics as shown in FIG. That is, the detected output value α from the nonlinear conversion circuit 320 is α = 0 when the output of the dividing circuit 318 is smaller than the first predetermined value θ1, and depends on the input value when the output is larger than the first predetermined value θ1. It becomes constant when it becomes larger than the second predetermined value θ2.

  The output of the non-linear conversion circuit 320 is supplied to the spreading circuit 321, subjected to a process of widening the non-emphasized region back and forth, and then output as a detection output value α of the non-emphasized region / non-emphasized amount detection circuit 30. In this example, the spreading circuit 321 spreads one sample as a non-enhanced region in the front-rear direction. The spreading circuit 321 may not be provided depending on the input video signal Vi to be applied.

  Next, the operation of the non-emphasized region / non-emphasized amount detection circuit 30 will be described with reference to FIGS. 12 and 13 showing output waveforms of the respective parts. Here, a case where an input video signal Vi including an edge portion with ringing as shown in FIG. 12A is supplied to the non-emphasized region / non-emphasized amount detection circuit 30 will be described.

  When the edge portion as shown in FIG. 12A is supplied to the high-pass filter 301, as the output S1, a signal that differentiates the edge portion is output as shown in FIG. 12B. The output signal S1 is passed through the absolute value circuit 302, and a signal as shown in FIG. 12C is obtained as the output signal S2. In FIG. 12B and thereafter, ringing is omitted for the sake of simplicity except for the waveform diagram of FIG.

  Then, after passing through the non-linear conversion circuits 303 and 304, respectively, they are supplied to the low-pass filters 305 and 306. From these low-pass filters 305 and 306, the output S2 of the absolute value conversion circuit 302 as shown in FIG. Is obtained by smoothing the output signal S3.

  Since the signal obtained by delaying the signal S3 shown in FIG. 12D by the delay circuit 310 is the output signal S4 at the sample position of interest, the signal shown in FIG. 12D is considered as the output S4. , 309 and 311, 312 outputs S 5, S 6 and S 7, S 8 are as shown in FIGS. 12E, 12 F, 12 G, and 12 H.

  Therefore, the output S9 of the maximum value detection circuit 317 is a signal obtained by combining the outputs S7 and S8 at the front part of the edge part as shown in FIG. 12 (I), and is output at the rear part of the edge part. The signal is a combination of S5 and S6. Then, when this is expanded by the circuit 321, a signal as shown in FIG.

  Therefore, by supplying the signal shown in FIG. 12 (J) as the detection output value α to the output control circuit 23, as shown in FIG. An output signal Vo that does not emphasize ringing is obtained.

  As can be seen from the above description, the delay circuits 308, 309, 311 and 312 are circuits for generating non-emphasized regions. Then, by changing the delay amounts of the delay circuits 308, 309, 311 and 312, it is possible to easily change and set the width of the non-emphasized region before and after the edge portion. In this example, two non-emphasized areas before and after the edge portion are generated by two delay circuits, but the number is also changed according to how wide the non-emphasized area is. Thus, a non-emphasized area having a desired width can be generated.

  Therefore, by checking in advance the occurrence of ringing that occurs in the target input video signal Vi and setting the number of delay circuits and the delay amount constituting the non-emphasized region setting circuit 307 according to the occurrence, The desired non-emphasized area can be obtained. Note that the non-emphasized region may be set in accordance with the occurrence state of ringing or the like, and may not be the preceding and following target sections around the edge portion.

  Note that when there is no flat portion before and after the edge portion, it is not noticeable even if there is ringing. Therefore, these portions do not need to be non-emphasized regions, and the detection output value α may be zero or a minute value. . In the non-emphasized region / non-emphasized amount detection circuit 30 of this embodiment, this point is also taken into consideration by the above-described configuration.

  That is, for example, when the input video signal Vi is a signal composed of only edges as shown in FIG. 13A, the output S1 of the high-pass filter 301 is almost input as shown in FIG. 13B. The signal appears as it is. Then, as shown in FIG. 13C, the absolute value circuit 302 obtains a signal S2 in which the signal S1 is all folded back to the positive polarity.

  Then, from the low-pass filters 305 and 306, as shown in FIG. 13D, a substantially DC signal S3 obtained by smoothing the high-frequency signal S2 is obtained. For this reason, as shown in FIG. 13E, the output signal S9 of the maximum value detection circuit 317 is also a substantially DC signal. Accordingly, the output of the dividing circuit 318 is obtained as a small constant value as shown in FIG. 13F, and the detected output value α is almost zero or a minute value. Therefore, the output video signal Vo is the same as that shown in FIG. As shown in G), the input video signal Vi becomes a signal in which high frequency is emphasized.

  In consideration of the fact that the level of ringing decreases as the distance from the edge portion increases, the signal of the non-emphasized area generated by the delay circuits 308 to 312 decreases as the distance from the edge decreases. You may make it be a simple signal.

  For example, in the above-described non-emphasized region / non-emphasized amount detection circuit 30, the output from the delay circuit farther from the target sample position is weighted so as to lower the level. For example, in the case of FIG. 5 described above, the levels of the outputs S5 and S8 of the delay circuits 308 and 312 are lowered as shown in FIGS. Weighting is performed, and the levels of the outputs of the delay circuits 309 and 311 are not lowered as shown in FIGS.

  In this way, as shown in FIG. 14E, the output S9 of the maximum value detection circuit 317 is a signal whose level becomes lower at the front part and the rear part of the edge part as it leaves the edge part. Ideally, as shown in FIG. 14F, a signal obtained by smoothing the output S9 is preferable.

[Other Embodiments and Modifications]
In the above description, the edge portion or the like is emphasized without emphasizing the ringing. However, the signal component may be lost when the image is compressed by MPEG (Moving Picture Experts Group), for example. As a cause, when mosquito noise is generated in a flat part near a signal with a large amplitude, the edge part with a large amplitude is emphasized without emphasizing the mosquito noise. The video signal processing apparatus according to the invention is applicable.

  Further, the video signal processing apparatus according to the present invention can be applied not only to the processing in the horizontal direction for the video signal but also to the processing in the vertical direction. That is, the present invention can be applied not only to ringing and mosquito noise generated in the horizontal direction of the screen but also to high-frequency emphasis without emphasizing mosquito noise generated in the vertical direction of the screen.

  Moreover, although the above-described configuration is a digital circuit configuration in which the input video signal is a digital video signal, it is of course possible to have an analog circuit configuration for an analog input video signal.

  When digital input video signals are targeted, the above-described video signal processing apparatus is not configured by a hardware digital circuit, but all processing is programmed and software is executed by a computer using the program. The processing can be executed by the processing.

It is a block diagram which shows the example of a whole structure of embodiment of the video signal processing apparatus by this invention. It is a figure for demonstrating the input-output characteristic of the one part circuit of the structure of FIG. It is a figure for demonstrating a digital filter. It is a figure which shows the example of the filter coefficient of a digital filter. FIG. 2 is a block diagram illustrating a more detailed configuration example of a part of the non-emphasized region / non-emphasized amount detection circuit in FIG. 1. It is a figure which shows the example of the filter coefficient of a digital filter. It is a figure which shows the example of the filter coefficient of a digital filter. It is a figure used for description of the circuit of FIG. It is a figure used for description of the circuit of FIG. It is a figure used for description of the circuit of FIG. FIG. 6 is a diagram for explaining input / output characteristics of a part of the circuit of FIG. 5. It is a wave form diagram used for operation | movement description of the circuit of FIG. It is a wave form diagram used for operation | movement description of the circuit of FIG. FIG. 6 is a diagram used for explaining another example of the circuit of FIG. 5. It is a figure for demonstrating the ringing of the edge part vicinity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 ... High frequency emphasis circuit, 21 ... High pass filter, 22 ... Non-linear conversion circuit, 23 ... Output control circuit, 24 ... Adder circuit, 30 ... Non-emphasis area / non-emphasis amount detection circuit, 301 ... High pass filter, 302 ... Absolute value , 303, 304... Non-linear conversion circuit, 305, 306... Low pass filter, 308 to 312 and 319, Delay circuit, 317, Maximum value detection circuit, 318.

Claims (18)

High frequency enhancement means for enhancing high frequency components of the input video signal;
A non-enhanced region / non-enhanced amount detecting means for obtaining a detection output corresponding to a non-emphasized region before and after an edge portion of the input video signal and a non-enhanced amount from the input video signal;
A video signal processing apparatus comprising: controlling the enhancement amount of the high frequency component in the high frequency enhancement means according to the detection output of the non-emphasis region / non-emphasis amount detection means. The video signal processing device according to claim 1,
The high frequency emphasis means is
A high-pass filter for extracting a high-frequency component of the input video signal;
Non-linear means that is supplied with the output of the high-pass filter and has non-linear input / output characteristics so as to emphasize the high-frequency component of the input video signal;
Signal output control means for controlling the signal amount of the output signal of the nonlinear means according to the detection output of the non-emphasized area / non-emphasized amount detection means;
Adding means for adding the output signal of the signal output control means to the input video signal;
A video signal processing apparatus comprising: The video signal processing device according to claim 1,
The non-emphasized region / non-emphasized amount detecting means includes
A high-pass filter for extracting a high-frequency component of the input video signal;
Absolute value obtaining means for obtaining an absolute value of the output signal of the high pass filter;
A first low pass filter for extracting a low frequency component of the output of the absolute value converting means;
By delaying the output of the first low-pass filter by an amount smaller than the first predetermined amount, with the position where the output of the first low-pass filter is delayed by a first predetermined amount as the signal position of interest, By obtaining a first output at a time point before the target signal position and delaying the output of the first low-pass filter by an amount larger than the first predetermined amount, Means for obtaining a second output of time;
Maximum value output means for supplying the first output and the second output as input signals and outputting a maximum value of the input signal;
And a detection output corresponding to a flat region before and after the edge portion is generated based on an output of the maximum value output means. The video signal processing apparatus according to claim 3, wherein
Dividing means for dividing the output of the maximum value output means by the delay of the low frequency component of the output of the absolute value means by the first predetermined amount;
A video signal processing apparatus that generates a detection output corresponding to the non-emphasized region and the non-emphasized amount based on an output of the dividing means. The video signal processing apparatus according to claim 3, wherein
A second low-pass filter for extracting a low-frequency component of the output of the absolute value converting means;
Dividing means for dividing the output of the maximum value calculating means by the output of the second low-pass filter delayed by the first predetermined amount;
A first non-linear processing means provided in a preceding stage of the first low-pass filter, wherein the input / output characteristics are lower than those in the case of linearity in a region of small amplitude and medium amplitude of the input signal;
A second non-linear processing means provided in a preceding stage of the second low-pass filter, wherein the input / output characteristics are higher than those in the linear case in the small amplitude and medium amplitude regions of the input signal;
A video signal processing apparatus comprising: The video signal processing apparatus according to claim 3, wherein
Each of the first output and the second output includes a plurality of delay outputs obtained by delaying the output of the first low-pass filter by different delay amounts,
The video signal processing apparatus characterized in that the output level of the output that is farther from the target signal position among the plurality of delayed outputs is lowered. A high frequency emphasizing step for emphasizing the high frequency components of the input video signal;
From the input video signal, a non-high frequency enhancement region / high frequency enhancement amount detection step for obtaining a detection output corresponding to a non-high frequency enhancement region and a high frequency enhancement amount before and after an edge portion of the input video signal;
A high-frequency component emphasis amount in the high-frequency emphasis step is controlled according to the detection output obtained in the non-high frequency emphasis region / high-frequency emphasis amount detection step. The video signal processing method according to claim 7,
The high frequency emphasis step includes
A high frequency component extracting step for extracting a high frequency component of the input video signal;
A non-linear processing step for emphasizing the high-frequency component extracted in the high-frequency component extracting step by processing the non-linear characteristic of the input / output characteristics;
A signal output control step of controlling the signal amount of the output signal of the nonlinear processing step according to the detection output in the non-emphasized region / non-emphasized amount detecting step;
An addition step of adding the output signal obtained in the signal output control step to the input video signal;
A video signal processing method comprising: The video signal processing method according to claim 7,
The non-high frequency emphasized region / high frequency emphasized amount detection step includes:
A high frequency component extracting step of extracting a high frequency component of the input video signal;
An absolute value conversion step for obtaining an absolute value of the high frequency component output obtained in the high frequency component extraction step;
A first low frequency component extracting step for extracting a low frequency component of the output of the absolute value converting step;
The low frequency obtained in the first low frequency component extraction step with the position obtained by delaying the low frequency component output obtained in the first low frequency component extraction step by a first predetermined amount as a target signal position By delaying the component output by an amount smaller than the first predetermined amount, a first output at a time point before the target signal position is obtained, and obtained in the first low frequency component extraction step Obtaining a second output at a later time than the signal position of interest by delaying a low-frequency component output by an amount greater than the first predetermined amount;
A maximum value output step of outputting the maximum value using the first output and the second output as input signals;
And a detection output corresponding to the non-emphasized region and the non-emphasized amount is generated based on the output of the maximum value output step. The video signal processing method according to claim 9, wherein
A division step of dividing the output of the maximum value output step by the low frequency component of the output of the absolute value conversion step delayed by the first predetermined amount;
A video signal processing method comprising: generating a detection output corresponding to the non-emphasized region and the non-emphasized amount based on an output of the division step. The video signal processing method according to claim 9, wherein
A second low frequency component extracting step for extracting a low frequency component of the output of the absolute value step;
A division step of dividing the output of the maximum value calculation step by the output of the second low frequency component extraction step delayed by the first predetermined amount;
A first non-linear operation is performed before the first low-frequency component extraction step, and performs processing of non-linear characteristics that are lower than those in the case of linearity in the regions of small and medium amplitudes of the input signal. Processing steps;
Second nonlinear processing is performed before the second low-frequency component extracting step, and performs processing of nonlinear characteristics in which the input / output characteristics are raised in the small amplitude and medium amplitude regions of the input signal as compared with the linear case. Steps,
A video signal processing method comprising: The video signal processing apparatus according to claim 9, wherein
Each of the first output and the second output includes a plurality of outputs obtained by delaying the output of the first low-frequency component extraction step by different delay amounts,
The video signal processing method characterized by lowering the output level of an output farther from the target signal position among the plurality of outputs. In order to emphasize the high frequency range of the input video signal,
High-frequency emphasis means that emphasizes the high-frequency component of the input video signal,
From the input video signal, a detection output corresponding to a non-emphasized area before and after an edge portion of the input video signal and a non-enhanced amount is obtained, and the enhanced amount of the high-frequency component in the high-frequency emphasizing unit according to the detected output Non-enhanced region / non-enhanced amount detection means for controlling
Video signal processing program to function as In the video signal processing program according to claim 13,
The high frequency emphasis means is
A high-pass filter for extracting a high-frequency component of the input video signal;
Non-linear means with non-linear input / output characteristics so that the output of the high-pass filter is supplied and the high-frequency component of the input video signal is enhanced,
A signal output control means for controlling the signal amount of the output signal of the non-linear means according to the detection output of the non-emphasized area / non-emphasized amount detecting means;
Adding means for adding the output signal of the signal output control means to the input video signal;
A video signal processing program comprising: a processing program that functions as: In the video signal processing program according to claim 13,
The non-emphasized region / non-emphasized amount detecting means includes
A high-pass filter for extracting a high-frequency component of the input video signal;
Absolute value obtaining means for obtaining an absolute value of an output signal of the high pass filter;
A first low-pass filter for extracting a low-frequency component of the output of the absolute value converting means;
By delaying the output of the first low-pass filter by an amount smaller than the first predetermined amount, with the position where the output of the first low-pass filter is delayed by a first predetermined amount as the signal position of interest, By obtaining a first output at a time point before the target signal position and delaying the output of the first low-pass filter by an amount larger than the first predetermined amount, Means for obtaining a second output of time;
Maximum value output means for supplying the first output and the second output as input signals and outputting the maximum value of the input signals;
A video signal processing program, comprising: a processing program functioning as: and generating a detection output corresponding to a flat region before and after the edge portion based on an output of the maximum value output means. The video signal processing program according to claim 15,
A second low-pass filter for extracting a low-frequency component of the output of the absolute value converting means;
Dividing means for dividing the output of the maximum value calculating means by the output of the second low-pass filter delayed by the first predetermined amount;
A first non-linear processing means provided in a preceding stage of the first low-pass filter, wherein the input / output characteristics are lower than those in the case of linearity in the small amplitude and medium amplitude regions of the input signal;
A second non-linear processing means having a non-linear characteristic that is provided in a preceding stage of the second low-pass filter, and whose input / output characteristics are higher than those in the linear case in a region of a small amplitude and a medium amplitude of the input signal;
A video signal processing program, comprising: a processing program that functions as: The video signal processing program according to claim 15,
A processing program that functions as a dividing unit that divides the output of the maximum value calculating unit by the low-frequency component of the output of the absolute value converting unit delayed by the first predetermined amount;
A video signal processing program that generates a detection output corresponding to the signal reduction region and the signal reduction amount based on the output of the dividing means. The video signal processing program according to claim 15,
Each of the first output and the second output includes a plurality of delay outputs obtained by delaying the output of the first low-pass filter by different delay amounts,
A video signal processing program characterized by lowering the output level of an output farther from the target signal position among the plurality of delayed outputs.

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