JP2006325154A - Signal correction device, receiver having signal correction device and signal correction program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a signal correction device, etc. for realizing highly precise correction of signals. <P>SOLUTION: In the signal correction device which corrects a video image or an image by a luminance signal and two color difference signals to be obtained from the video image or the image, it has a three primary color value conversion part which converts the luminance signal and the two color difference signals into three primary color values, a delay part which delays the three primary color values by the number of predetermined pixels, a three primary color value prediction part which predicts the three primary color values of the predetermined pixels from the three primary color values to be obtained by the delay part and a comparative evaluation part which compares and evaluates predicted values to be obtained by the three primary color value prediction part with the three primary color values to be obtained by the three primary color value conversion part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a signal correction apparatus, a reception apparatus having the signal correction apparatus, and a signal correction program, and more particularly to a signal correction apparatus for realizing highly accurate signal correction, a reception apparatus having the signal correction apparatus, and The present invention relates to a signal correction program.

  Conventionally, in digital image processing typified by video encoding and filter processing, image processing is performed on a video signal composed of a luminance signal and a color difference signal. Further, it is originally expressed by a combination of the three primary colors (red (R), blue (B), and green (G)), and it is known that human vision has different sensitivities depending on the combination of the three primary colors.

  Because of this difference in sensitivity, the pixel information expressed by the three primary colors is converted into the most visually sensitive luminance axis and two color difference axes for image processing, and each converted information is weighted. The technique to do is done.

In particular, the difference in visual sensitivity with respect to luminance and chrominance signals is actively utilized, and video signals called 4: 2: 2 format, which suppresses the band of chrominance signals, are used even in general image quality high-quality formats. And used as a signal that is the basis of image processing (see, for example, Non-Patent Document 1 and Non-Patent Document 2). In the 4: 2: 2 format described above, an image is generally formed on a television screen by pixels arranged on a scanning line, and the pixels are a luminance signal Y representing the brightness of the image and two color difference signals representing the color of the image. It consists of C _b and C _r . In this case, _Y described _above, C b, the ratio of the three components of _{C r} 4: 2: is a representation in the form 2.

  Also, in coding systems represented by MPEG-2 (Motion Picture Experts Group-2) and DV (Digital Video) standards, the 4: 2: 0 format, which further suppresses the band of color difference signal information, and 4: 1: A video signal called one format is also used. This is because the human eye is sensitive to the luminance signal, and the color difference signal is not significantly affected by the human visual characteristics compared to the luminance signal, so the coding efficiency is improved by reducing the information of the color difference signal. It is used for.

As a conventional technique, in order to reduce deterioration factors such as block noise caused by signal deterioration in encoding processing, a technique for performing correction processing on an image using a filter that realizes blurring processing or the like on a decoded signal (For example, refer to Patent Document 1).
Impress Standard Textbook Series, “H.264 / AVC Textbook”, p. 40. Kyoritsu Publishing, "Information compression technology for digital broadcasting and the Internet", pp. 9-10. JP-A-10-191332

  By the way, in the conventional image processing, the luminance signal and the color difference signal are processed independently. Therefore, in the case of irreversible image processing, the degree of deterioration of the luminance signal and the color difference signal in the decoded video is different.

  Further, it is known that human visual characteristics are not sensitive to different colors when perceiving different colors, but are sensitive to differences in adjacent colors. Therefore, as described above, when the luminance signal and the color difference signal are individually deteriorated by irreversible image processing, the degree of deterioration of each signal component is different, so that the video quality is deteriorated.

  For example, the variation in the degree of deterioration of each signal in the boundary part is a phenomenon in which the boundary formed by the luminance signal and the boundary formed by the color difference signal do not match due to individual deterioration, and the color blurs across the boundary. Etc. are likely to occur. Such deterioration particularly occurs in an encoding process aiming at high compression.

  Moreover, the correction process shown in Patent Document 1 is a process of dulling a rapid change in a signal, and the process is performed independently between each of the luminance signal and the color difference signal. That is, in the correction process described above, the luminance signal and the color difference signal are individually filtered, and the luminance signal and the color difference signal are not integrated. Therefore, as described above, the image processing causes different changes in individual signals, resulting in a problem that the image is deteriorated.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a signal correction apparatus for realizing highly accurate signal correction, a receiving apparatus having the signal correction apparatus, and a signal correction program. And

  In order to solve the above problems, the present invention employs means for solving the problems having the following characteristics.

  According to a first aspect of the present invention, in the signal correction device for correcting the video or the image by the luminance signal obtained from the video or the image and the two color difference signals, the luminance signal and the two color difference signals are converted into three primary color values. Three primary color value conversion units, a delay unit that delays the three primary color values by a predetermined number of pixels, a three primary color value prediction unit that predicts the three primary color values of a predetermined pixel from the three primary color values obtained by the delay unit, and the three primary color value prediction unit And a comparative evaluation unit that compares and evaluates the predicted value obtained by the above and the three primary color values obtained by the three primary color value conversion unit.

  According to the first aspect of the present invention, highly accurate signal correction can be realized for a video or an image. Thereby, in the digital encoding system, the quality of the other two signals can be improved from one signal as a reference.

  According to a second aspect of the present invention, the three primary color value prediction unit is configured to use the predetermined pixel in the three primary color space based on a change amount of a reference signal based on at least one of the luminance signal and two color difference signals. The three primary color values are predicted.

  According to the second aspect of the present invention, the three primary color values of a predetermined pixel are predicted with high accuracy from the relationship between at least one of the luminance and the two color differences and a straight line passing through the origin and the three primary color values in the three primary color space. can do.

  According to a third aspect of the present invention, the three primary color value prediction unit predicts three primary color values based on the luminance signal, and the comparison evaluation unit is configured to perform the comparison based on the three primary color values obtained by the three primary color value prediction unit. Two color difference signals are corrected.

  According to the third aspect of the invention, the quality of the color difference signal can be improved. In particular, it is possible to improve the quality of a color difference signal that allows a certain degree of degradation in a video transmission method based on a digital encoding method that is currently widely used.

  The invention described in claim 4 is characterized in that the comparative evaluation unit outputs the predicted value or the three primary color values based on a luminance difference amount between pixels to be compared.

  According to the fourth aspect of the present invention, the color difference signal encoded with a larger error than the luminance signal is highly accurate based on the difference amount of the luminance signal encoded with less error in the normal encoding method. Can be corrected.

  In the invention described in claim 5, the comparative evaluation unit sets an allowable error range based on a minimum discrimination threshold, compares the luminance difference amount with the allowable error range, and within the allowable error range. In some cases, the predicted value is output.

  According to the fifth aspect of the present invention, the pixel value can be corrected so that the change in the three primary color ratios is reduced. Thereby, highly accurate signal correction can be realized.

  The invention described in claim 6 is a receiving apparatus including the signal correction apparatus according to any one of claims 1 to 5.

  According to the sixth aspect of the present invention, it is possible to realize high-precision signal correction for video or images in the receiving device. Thereby, the quality of the color difference signal in the digital encoding method can be improved.

  According to a seventh aspect of the present invention, there is provided a signal correction program for causing a computer to execute signal correction processing for correcting the video or the image by using the luminance signal obtained from the video or the image and two color difference signals. Three primary color value conversion processing for converting two color difference signals into three primary color values, delay processing for delaying the three primary color values by a predetermined number of pixels, and three primary colors for predicting the three primary color values of a predetermined pixel from the three primary color values obtained by the delay processing The computer is caused to execute a value prediction process, a comparison value obtained by the three primary color value prediction process, and a comparative evaluation process for comparing and evaluating the three primary color values obtained by the three primary color value conversion process.

  According to the seventh aspect of the present invention, it is possible to realize highly accurate signal correction for a video or an image. Thereby, in the digital encoding system, the quality of the other two signals can be improved from one signal as a reference. Moreover, the signal correction process in the present invention can be easily realized by installing the execution program in the computer.

  According to the present invention, highly accurate signal correction can be realized.

<Outline of the present invention>
In the present invention, a video signal or an image signal expressed by a luminance signal and a color difference signal is converted into a three primary color signal, and correction is performed using the three primary color values in the three primary color space using the statistical properties.

More specifically, a video signal or an image signal is generally measured by measuring the intensity of the three primary colors of red (R), blue (B), and green (G) in a photographing device and recording a luminance signal ( Y) and the three primary colors for transmission of the two color difference signals (C _r , C _b ). In the present invention, the three primary colors mean the three primary colors R, G, and B. In general, it is known that the pixel values of adjacent pixels are very close to each other as a statistical property in a natural image (for example, Ohm, “Advanced Technology Introduction Series Image Information Compression”, pp. 75). -77.) Such a property is actively used in encoding techniques such as DPCM (Differential Pulse Code Modulation) and MPEG, but is only used for individual signals of luminance signals or color difference signals. .

  Here, since the luminance signal and the color difference signal described above have a one-to-one correspondence with the three primary color signals, the same property can be applied to the three primary color signals. Therefore, the present invention converts the luminance signal and the two color difference signals into the three primary color signals using the statistical properties of the predetermined pixels such as the adjacent pixels described above, and the pixel value so that the change in the three primary color ratios between the pixels is reduced. The video signal or the image signal is corrected by correcting.

  In the following, a signal correction apparatus according to the present invention having the above-described features, a receiving apparatus having the signal correction apparatus, and a signal correction program are described in detail with reference to the drawings. In the signal correction apparatus described later, for example, a luminance signal and a color difference signal (YC signal) obtained by decoding an encoded video signal or image signal received on the receiving apparatus side via a transmission line such as a communication network. A signal correction apparatus for correcting the above will be described.

<Example>
FIG. 1 is a diagram illustrating a configuration example of a signal correction apparatus according to the present invention. The signal correction apparatus 10 illustrated in FIG. 1 is configured to include a YC-RGB conversion unit 11, a delay unit 12, an RGB prediction unit 13, and a comparative evaluation unit 14.

  The signal correction apparatus 10 inputs the YC signal by the YC-RGB conversion unit 11. The YC-RGB converter 11 converts the input YC signal into three primary color (RGB) signals for each pixel.

  Note that the YC-RGB converter 11 converts the final video or image signal corrected according to the present invention into a 4: 4: 4 band, for example, by using a band expansion filter or the like according to restrictions of the display device. RGB conversion may be performed after expansion.

  This is because the input YC signal has a format such as 4: 2: 2 or 4: 2: 0 as described above, but the RGB signal has a very large difference between the R, G, and B signals. Therefore, in order to make the ratio of each signal component uniform, the conversion is performed after extending the band of the YC signal to 4: 4: 4 format. Thereby, it can convert into RGB signal with high precision.

  The conversion method from the YC signal to the RGB signal is not particularly limited. For example, an appropriate conversion method such as “ITR-U recommendation 601/709” or the like is used according to the material image. Perform conversion. Further, the YC-RGB conversion unit 11 outputs the converted RGB signal to the delay unit 12 and the comparison evaluation unit 14.

  The delay unit 12 delays the pixel information in the RGB signal obtained from the YC-RGB conversion unit 11 by a predetermined number of pixels. In this embodiment, the delay unit 12 delays one pixel. However, the present invention is not limited to this, and a comparative evaluation unit 14 (to be described later) performs comparative evaluation between pixels. Therefore, a delay corresponding to the predetermined number of pixels is performed. That is, the delay unit 12 delays at least one pixel. Further, the delay unit 12 outputs the delayed pixel information to the RGB prediction unit 13.

  The RGB prediction unit 13 predicts the RGB value of a predetermined pixel (an adjacent pixel in this embodiment) based on the RGB signal for each pixel obtained by the delay unit 12. A specific prediction example of RGB values will be described later. The RGB prediction unit 13 outputs the predicted RGB value to the comparative evaluation unit 14. The comparative evaluation unit 14 performs comparative evaluation using the RGB value obtained by the RGB prediction unit 13 and the actual RGB value (three primary color values) obtained by the YC-RGB conversion unit 11 to correct the signal. In this embodiment, since the delay unit 12 delays one pixel, the pixel evaluated by the comparative evaluation unit 14 is a pixel one pixel after the pixel used to calculate the predicted value, that is, Three primary color values of horizontally adjacent pixels.

  Further, as a result of the comparative evaluation, the comparative evaluation unit 14 outputs either the predicted RGB value (prediction value) obtained by the RGB prediction unit 13 or the actual RGB value (three primary color values).

<Specific prediction example of RGB values>
Next, an example of RGB value prediction in the RGB prediction unit 13 described above will be specifically described. FIG. 2 is a diagram illustrating an example of a relationship between a pixel value in the RGB space and a luminance axis. FIG. 3 is a diagram illustrating an example of the change amount of the pixel value in the RGB space.

  First, let the RGB values in the current pixel obtained from the video or image input by the YC-RGB converter 11 be (R, G, B). Here, the RGB values of the adjacent pixels to be compared are on a straight line 1 or a straight line 1 passing through the two points of the origin (0, 0, 0) and the above-described (R, G, B) in FIG. It can be predicted to be located near. Here, the straight line l described above is expressed by the following equation (1) (linear equation).

なお、（１）式において、ｔは媒体変数を示す。

In the equation (1), t represents a medium variable.

  On the other hand, in FIG. 2, the Y-axis that is a luminance signal is based on a conventional standard (for example, standard for standard television broadcasting [BT.601], standard for high-vision broadcasting [BT.709]) in the RGB space. The direction vector v = (1,1,1) is a straight line passing through the origin (0,0,0).

By the way, as described above, adjacent pixels have substantially the same color, the component ratios of RGB values are substantially equal, and the luminance signal tends to leave more characteristics of the original picture signal than the color difference signal. Further, as described above, the luminance signal Y has a greater visual influence than the color difference signals C _b and C _r . From the above, based on the Y-axis in the three-dimensional space of the YC _b C _r axis, to predict the RGB values of adjacent pixels.

  That is, as shown in FIG. 3, assuming that the color difference changes on the straight line 1 (color difference change amount δc), and the direction vector in the RGB space of the luminance signal Y axis is v, the predicted RGB value (Predicted values) (R ′, G ′, B ′) can be estimated as in the following equation (2).

ここで、δｙは輝度の変化量を示し、ｙ＋δｙは予測の対象画像の輝度に等しい。

Here, δy indicates the amount of change in luminance, and y + δy is equal to the luminance of the prediction target image.

  The RGB prediction unit 13 calculates predicted values (R ′, G ′, B ′) by the above-described equation (2), and outputs the calculated RGB values to the comparative evaluation unit 14. In addition, the comparison / evaluation unit 14 uses the actual three primary color values (decoded values) (R, G, B) and the predicted values (R ′, G ′, B ′) to evaluate the validity.

<Comparison evaluation part 14: Evaluation method>
Next, the evaluation method in the comparative evaluation part 14 mentioned above is demonstrated. The comparative evaluation unit 14 is based on the actual three primary color values (R, G, B) obtained by the YC-RGB conversion unit 11 and the predicted values (R ′, G ′, B ′) obtained from the RGB prediction unit 13. And evaluate the legitimacy.

  Specifically, for example, the validity is evaluated by using the following expression (3), and any of the predicted values (R ′, G ′, B ′) or the actual three primary color values (R, G, B) is used. One of these values is output.

ここで、上述した（３）式において、Ｋは予め設定される閾値である。なお、Ｋの値は任意に設定することができるが、より画像データに対応して正確にＫの値を求める場合、例えばＪＮＤ（Ｊｕｓｔ Ｎｏｔｉｃｅａｂｌｅ Ｄｉｆｆｅｒｅｎｃｅ：最小弁別閾）によって求められる閾値を利用することもできる。つまり、ＪＮＤは、心理学上、色等の同種の刺激を変化させたとき、その相違を感知できる最小の刺激差を示すものであり、最小可知差異、丁度可知差異ともいわれる。また、閾値Ｋは、人によって感知できる最小の輝度差が異なるため、例えば平均値を設定してもよい。

Here, in the above-described equation (3), K is a preset threshold value. The value of K can be arbitrarily set. However, when the value of K is more accurately obtained corresponding to the image data, for example, a threshold value obtained by JND (Just Notifiable Difference) is used. You can also. In other words, JND indicates the minimum stimulus difference that can sense the difference when the same type of stimulus such as color is changed in psychology, and is also referred to as the minimum noticeable difference or just the noticeable difference. The threshold value K may be set to an average value, for example, because the minimum luminance difference that can be detected varies depending on the person.

  That is, as shown in the above-described equation (3), the comparative evaluation unit 14 obtains an image obtained by the difference between the primary colors of red, blue, and yellow (R′−R, G′−G, B′−B). If the information is such that the difference is perceptible, the three primary color values (R, G, B) are output, and if the difference is not perceptible, the predicted value (R ′, G ′, B ′). ) Is output.

  As described above, a video signal or an image signal can be corrected with high accuracy by the signal correction apparatus shown in this embodiment. Thereby, in the digital encoding system, the quality of the other two signals can be improved from one signal as a reference.

In the above-described embodiment, the conversion to RGB is performed using the luminance signal (Y signal) as a reference. However, the present invention is not limited to this, and Cb or Cr of the color difference signal is used as a reference. Also good. _{Also, Y,} C b, a plurality may be used as a reference of the _{C r.}

For _example, Y, C b, among the signals of the C _r, can be based on the large difference signal between pixels. Incidentally, generally chrominance signal C _b, C _r are the relatively smooth pixels not seen so much changed as compared with the luminance signal Y, and adding a predetermined coefficient C _b signals, the C _r signal It is preferable to make a comparison with the Y signal. _Furthermore, Y, C b, By comparing relative to the respective C _r, for example be subjected to a treatment such outputs a change amount fewest was the value (closest value to a straight line and ideal) therein Good.

<Other embodiments>
Here, in the above-described embodiment, an example in which pixels between horizontal adjacent pixels are corrected is shown, but the correction method in the present invention is not limited to this. For example, the comparative evaluation may be performed using four neighboring pixels that are horizontally and vertically adjacent to one pixel. Further, comparative evaluation may be performed using eight neighboring pixels adjacent to one pixel in the eight surrounding directions.

  As described above, when correcting pixels in the vicinity of four or eight, for example, after calculating predicted values of four or eight corresponding neighboring pixels, respectively, a weighted average value of the predicted values is obtained. A comparative evaluation may be performed between the average value and the actual three primary color values. Further, the comparison evaluation between each predicted value and the actual three primary color values may be performed, and the value that is larger in the evaluation result (in the case of the same number, a preset value) may be output.

<Receiving device>
Note that the signal correction apparatus 10 according to the present invention described above can be provided in a receiving apparatus, for example. Thus, by configuring the present invention at the subsequent stage of the decoding process of the receiving apparatus, the quality of the color difference signal can be improved, and the final improvement in the quality of the decoded signal can be realized. Here, a configuration example of a receiving apparatus having a signal correction apparatus according to the present invention will be described with reference to the drawings.

  FIG. 4 is a diagram illustrating a configuration example of a receiving apparatus having a signal correction apparatus according to the present invention. As a receiving form of the receiving apparatus shown below, a video signal composed of an MPEG2 encoding method is wirelessly transmitted as an example, and a form for receiving the signal and providing the signal to the receiver is shown. The receiving form in the invention is not limited to this.

  4 is configured to include a reception antenna 21, a low noise amplifier 22, a frequency conversion unit 23, a demodulation unit 24, an MPEG2 decoder 25, and a signal correction device 26. The receiving device 20 is connected to a monitor 27 that is a display device.

  First, the receiving device 20 receives the radio wave of the video signal transmitted from the transmitting side with the receiving antenna 21. The receiving antenna 21 outputs the received signal to the low noise amplifier 22. The low noise amplifier 22 amplifies the transmission attenuation of the signal obtained by the receiving antenna 21 and outputs the amplified signal to the frequency converter 23. The frequency conversion unit 23 frequency-converts (down-converts) the signal obtained from the low noise amplifier 22 and outputs it to the demodulation unit 24. The demodulator 24 demodulates the digital modulation signal obtained from the frequency converter 23 and outputs the demodulated signal to the MPEG2 decoder 25.

  The MPEG2 decoder 25 decodes the demodulated digital signal obtained from the demodulator 24 and outputs the decoded signal to the signal correction device 26. The signal correction device 26 corrects the input signal as described above, and outputs the corrected video signal to the monitor 27. The monitor 27 displays the video corrected by the signal correction device 26. Thus, the user can view an image that has been corrected by the signal correction device of the present invention and has improved image quality.

  The signal correction apparatus according to the present invention is not limited to the above-described receiving apparatus, and may be provided in an apparatus that performs image processing.

<Signal correction program>
Here, the signal correction device according to the present invention can perform the signal correction processing according to the present invention using the dedicated device configuration described above, but generates an execution program capable of causing a computer to execute the processing in each configuration. For example, the signal correction processing according to the present invention can be realized by installing the program in a general-purpose personal computer, workstation or the like.

<Hardware configuration>
Here, a hardware configuration example of a computer capable of executing signal correction processing according to the present invention will be described with reference to the drawings. FIG. 5 is a diagram illustrating an example of a hardware configuration capable of realizing the signal correction processing according to the present invention.

  5 includes an input device 31, an output device 32, a drive device 33, an auxiliary storage device 34, a memory device 35, a CPU (Central Processing Unit) 36 for performing various controls, and a network connection device. 37, and these are connected to each other by a system bus B.

  The input device 31 has a pointing device such as a keyboard and a mouse operated by the user, and inputs various operation signals such as a program execution instruction from the user. The output device 32 has a monitor for displaying various windows and data necessary for operating the computer main body for performing the processing according to the present invention, and displays the execution progress and results by the control program of the CPU 36. Can do.

  Here, in the present invention, the execution program installed in the computer main body is provided by, for example, the recording medium 38 such as a CD-ROM. The recording medium 38 on which the program is recorded can be set in the drive device 33, and the execution program included in the recording medium 38 is installed in the auxiliary storage device 34 from the recording medium 38 via the drive device 33.

  Further, the drive device 33 can record the execution program according to the present invention on the recording medium 38. Thereby, using the recording medium 38, it can be easily installed in a plurality of other computers, and signal correction processing can be easily realized.

  The auxiliary storage device 34 is a storage means such as a hard disk, and can store an execution program in the present invention, a control program provided in a computer, and the like, and can perform input / output as necessary.

  Based on a control program such as an OS (Operating System) and an execution program read and stored by the memory device 35, the CPU 36 performs various operations and inputs / outputs data to / from each hardware component. Each process in the signal correction process can be realized by controlling the process. Various information necessary during the execution of the program can be acquired from the auxiliary storage device 34 and can be stored.

  The network connection device 37 acquires an execution program from another terminal connected to the communication network or executes the program by connecting to a communication network such as a telephone line or a LAN (Local Area Network) cable. The execution result obtained in this way or the execution program in the present invention can be provided to other terminals or the like.

  With the hardware configuration as described above, the signal correction processing described above can be realized at a low cost without requiring a special device configuration. In addition, signal correction processing can be easily realized by installing a program.

  Next, a processing procedure in the execution program will be described using a flowchart.

<Signal correction processing>
FIG. 6 is a flowchart showing an example of a signal correction processing procedure in the present invention. Note that the processing procedure to be described later shows only the correction portion of the signal that has already been decoded from the encoded signal. Further, the processing procedure to be described later shows an example in which a signal is corrected by comparing horizontal adjacent pixels, but the evaluation target pixel in the present invention is not limited to this. For example, as described above, there are four neighborhoods. Alternatively, comparative evaluation using eight neighboring pixels may be performed.

  First, a pixel in the YC signal is input (S01), and the input pixel is converted to RGB (S02). Further, in order to compare and evaluate the predicted value between the horizontal adjacent pixels and the actual three primary color values, the RGB converted three primary color values are delayed by one pixel (S03).

  Next, the RGB value of the next adjacent pixel is predicted based on the three primary color values delayed in S03 (S04). In addition, as a prediction method, the example of prediction mentioned above etc. can be used, for example.

  Next, a comparative evaluation is performed between the predicted value obtained by the process of S04 and the actual three primary color values of the next pixel obtained by the process of S02 (S05). Here, as a result of the comparative evaluation, it is determined whether or not the difference between the predicted value and the three primary color values is within the allowable error range (S06). If the difference is within the allowable error range (YES in S06), the prediction is performed. A value is output (S07).

  If the difference between the predicted value and the three primary color values is not within the allowable error range (NO in S06), the actual three primary color values converted in S02 are output (S08).

  Next, after completion of the processing of S07 or S08, it is determined whether or not the signal correction is finished (S09), and when the signal correction is not finished, for example, there is a video signal that has not been signal-corrected yet (NO in S09) ) Returns to S01 and corrects the target input signal. If the signal correction is to be ended (YES in S09), the signal correction process is ended.

  By generating a signal correction program that causes a computer to execute the signal correction processing described above, and installing and executing the program on a computer or the like, high-accuracy signal correction can be realized. Thereby, in the digital encoding system, the quality of the other two signals can be improved from one signal as a reference.

  As described above, according to the present invention, it is possible to realize highly accurate signal correction for a video or an image. Specifically, the video signal that has been subjected to irreversible image processing is corrected, the video signal represented by the luminance signal and the color difference signal is converted into the three primary color signals, and the luminance signal is obtained using the statistical properties of the three primary color signals. The color difference signal can be corrected. Thereby, in the digital encoding system, the quality of the other two signals can be improved from one signal as a reference.

  In particular, in the encoding process, deterioration of the overall decoding quality is suppressed by encoding the luminance signal accurately and the color difference signal relatively coarsely from the difference in visual sensitivity. For this reason, the deterioration of the color difference signal is larger than that of the luminance signal, and a difference occurs in accuracy between signals. Therefore, in the present invention, the three primary color values obtained by converting the actual adjacent pixels by obtaining the three primary color values of the pixels from the luminance signal and the color difference signal, predicting the three primary color values of the adjacent pixels from the luminance difference amount between the adjacent pixels, and And the predicted value are compared, and if both are within an allowable error range, the predicted value is output as a correction value, whereby high-precision signal correction can be realized.

  In addition, the signal correction apparatus according to the present invention can be provided, for example, at the subsequent stage of the decoding process of the receiving apparatus, so that the quality of the color difference signal can be improved, and the final improvement in the quality of the decoded signal can be realized.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to such specific embodiments, and various modifications, within the scope of the gist of the present invention described in the claims, It can be changed.

It is a figure which shows one structural example of the signal correction apparatus in this invention. It is a figure which shows an example of the relationship between the pixel value on RGB space, and a luminance axis. It is an example for demonstrating the variation | change_quantity of the pixel value in RGB space. It is a figure which shows one structural example of the receiver which has a signal correction apparatus in this invention. It is a figure which shows an example of the hardware constitutions which can implement | achieve the signal correction process in this invention. It is a flowchart which shows an example of the signal correction processing procedure in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,26 Signal correction apparatus 11 YC-RGB conversion part 12 Delay part 13 RGB prediction part 14 Comparison evaluation part 20 Reception apparatus 21 Reception antenna 22 Low noise amplifier 23 Frequency conversion part 24 Demodulation part 25 MPEG2 decoder 31 Input apparatus 32 Output apparatus 33 Drive device 34 Auxiliary storage device 35 Memory device 36 CPU
37 Network connection device 38 Recording medium

Claims (7)

In a signal correction apparatus that corrects the video or image by a luminance signal obtained from the video or image and two color difference signals,
A three-primary color value converter that converts the luminance signal and the two color difference signals into three primary color values;
A delay unit that delays the three primary color values by a predetermined number of pixels;
Three primary color value prediction units for predicting the three primary color values of a predetermined pixel from the three primary color values obtained by the delay unit;
A signal correction apparatus comprising: a comparative evaluation unit that compares and evaluates the predicted value obtained by the three primary color value prediction unit and the three primary color values obtained by the three primary color value conversion unit. The three primary color value prediction unit
The three primary color values of the predetermined pixel in a three primary color space are predicted from a change amount of a reference signal with at least one signal of the luminance signal and the two color difference signals as a reference. Signal correction device. The three primary color value prediction unit
Predicting the three primary color values based on the luminance signal,
The comparative evaluation unit
3. The signal correction apparatus according to claim 1, wherein the two color difference signals are corrected based on the three primary color values obtained by the three primary color value prediction unit. The comparative evaluation unit
The signal correction apparatus according to claim 1, wherein the prediction value or the three primary color values are output based on a luminance difference amount between pixels to be compared. The comparative evaluation unit
An allowable error range is set based on a minimum discrimination threshold, the luminance difference amount is compared with the allowable error range, and the predicted value is output if the allowable error range is within the allowable error range. 5. The signal correction apparatus according to 4.   A receiving device comprising the signal correction device according to any one of claims 1 to 5. In a signal correction program for causing a computer to execute signal correction processing for correcting the video or image by using a luminance signal obtained from the video or image and two color difference signals,
Three primary color value conversion processing for converting the luminance signal and the two color difference signals into three primary color values;
A delay process for delaying the three primary color values by a predetermined number of pixels;
Three primary color value prediction processing for predicting the three primary color values of a predetermined pixel from the three primary color values obtained by the delay processing;
A signal correction program for causing a computer to execute a comparative evaluation process for comparing and evaluating a predicted value obtained by the three primary color value prediction process and a three primary color value obtained by the three primary color value conversion process.

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