JPH0344189A - video signal modification equipment - Google Patents

Abstract

PURPOSE:To attain interpolation with higher accuracy by interpolating an interpolated data generated from a picture element with stronger correlation than the correlation of picture elements in the vicinity of an erroneous data while its priority is raised. CONSTITUTION:Which of two data, a correction data generated by a means 16, a correction data generated by a means 17, is closer to a true value depends on a pattern. When the correction data generated by a means 16 is closer to the true value, a change in a color and a brightness is less between a data used for the generation and the data of error picture element and the correlation of the pattern in the horizontal direction is made stronger. When the correction data generated by a means 17 is closer to the true value conversely, the correlation of the pattern in the vertical direction is made stronger. A means 18 detecting the strength of the correlation in the horizontal and vertical directions changes over the priority on the signal processing by the means 16, 17 depending on the output of the means 16, 17. Thus, highly accurate interpolation is attained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention encodes a digital signal obtained by sequential sampling and quantization of analog information, and detects that the sample data in the encoded data is erroneous data. In some cases,
The present invention relates to an interpolation device that generates and outputs correct data as interpolation data to replace the erroneous sample data by interpolating other correct sample data.

[Conventional technology]

As a conventional encoded data error correction (correction) device, when the analog information signal is an audio signal,
Doi and Iga co-authored “Digital Audio” (Showa 57)
As stated in P2O3, 210 (published by Radio Technology Co., Ltd.), there is a previous value holding circuit that holds the sample data immediately before the error data and replaces it with the error data, and a An average value interpolation circuit is known that takes an average value and uses the average value data as interpolated data in place of error data. In addition, when the analog information signal is a video signal,
As described in Publication No. 0, a code error correction (dropout compensation) device was known that replaces error data with data extracted from a signal in a horizontal scanning period immediately before the horizontal scanning period that includes the error data. .

[111 m to be solved by the invention] Regarding the above-mentioned prior art, in an interpolation device using a previous value holding circuit or an average value interpolation circuit applied to a digital audio signal, a composite video signal in which a chrominance signal component is superimposed on a luminance signal component is used. No consideration is given to the interpolation accuracy when the correlation between adjacent sample data is small, as in the case of ft. There is a problem in that when a video signal is displayed on a screen, the image quality deteriorates significantly.

On the other hand, in the above code error correction device applied to a video signal, when applied to a composite video signal,
The signal (data) for one line before the horizontal scanning line (signal line) where the error data occurred is stored in memory, and the signal is read out and separated into a luminance signal component and a color signal component, and each is roughly divided into After an appropriate time delay of one line, the color signal components are matched to a phase corresponding to the color burst phase of the signal line in which the error data has occurred, and then combined and replaced with the signal line containing the error data.

However, even with this technology, since there is an adjustment of the delay amount to match the phase of one color signal component, there is no consideration given to truly high-precision interpolation and fx 5, resulting in one image quality deterioration. The problem was solved and it was 1K. Furthermore, a circuit for separating the composite video signal into a luminance signal component and a color signal component is required, resulting in a drawback that the circuit scale becomes large.

The object of the present invention is to solve the above-mentioned drawbacks of the prior art.

An object of the present invention is to provide an interpolation device which can perform highly accurate error data correction with a single-circuit circuit configuration and hardly causes image quality deterioration even when applied to a composite video signal.

[! Means for Solving a Problem] In order to achieve the above object, the present invention encodes a digital signal obtained by sequentially sampling and quantizing analog information, and eliminates the error in sample data that is lost in the encoded data. data, by interpolation between other valid sample data.

In an interpolation device that creates correct data as interpolation data in place of the erroneous sample data.

Focusing on the premise of performing interpolation calculations (there is a high probability that nearby data have the same brightness of 9 colors, that is, there is a high probability that there is a correlation), in order to perform interpolation calculations with higher accuracy, By changing the priority between multiple interpolation data according to the strength of horizontal correlation and vertical correlation in the vicinity of error data, interpolation accuracy is improved by using corrected data calculated from data with stronger correlation. It is possible.

[Effect]

Among the two data, the corrected data generated by means of exclamation and the corrected data generated by means αD, which data is closer to the true value differs depending on the picture. When the corrected data by the means αQ is brought closer to the true value, there will be fewer changes in color and brightness between the data used for generation and the data of the error pixel. In other words, the correlation between the patterns in the horizontal direction is strong < tx. On the contrary, the above means (17
) is made closer to the true value,
There is a strong correlation between the patterns in the vertical direction. At the end of the means α0 for detecting the strength of correlation between the horizontal direction and the vertical direction, according to the outputs of the above means 4 and the above means α,
17) to switch the signal processing priority.

〔Example〕

An embodiment of the present invention will be explained below with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing the arrangement of pixel data on a television screen.

In FIG. 1, 1 is a video data input terminal, 2 to 8
are data registers; 2, 4, 5, 6, and 7 delay data by one clock each, and 3 and 8 delay data by 908 clocks each. 9 to 15 are data output terminals, respectively, and NT
If the sampling data is 4f of the SC method, the pixels N, J, and II shown in FIG. 2, respectively.

Appears to be G, F, and C. Reference numeral 16 denotes means for generating correction data, which is currently performing the calculation act--(F+r) in order to generate correction data for pixel H. 17 is another means for generating correction data. Similarly, in order to generate correction data for pixel H, G+J−(C+N
) is being calculated. 18 is a means to measure the strength of the horizontal and al quadrature correlations near the erroneous data, and l p−Kl<
The determination result of l c-Nl is output. 19 and 20
is an output terminal, from the terminal 19, the first candidate generation theta for correction is output, and from the terminal 20, the second candidate generation theta for correction is output. 21 and 22 are data selectors, and when the output of the determining means 18 is "true", the output of the generating means 16 is selected as the first candidate, and the generating means 17
If the output of the determining means 18 is "scratch", the output of the generating means 16 is designated as the second candidate, and if the output of the determining means 18 is "scratch", the output of the generating means 16 is determined as the second candidate.
It works so that the output of 7 is the first candidate.

In this embodiment, the output of the generating means 16 is.

The output of the generating means 17 is It is.

In order for the calculation results by the generation means 16 and 17 to be valid as correction data for the pixel H, the approximate expressions of equations (2) and (4) must be established.

These approximate expressions are based on the correlation of one image data, that is, if pixels are close together, they are likely to have similar color and brightness.

Therefore, which of the calculation results of equation (1) and equation (3) is more accurate depends on which of the approximate expressions of equation (2) and equation (4) holds true more accurately. be.

Therefore, F-zl <IC-#l ・・・・・・・・・・・・
・・・・・・・・・・・・・・・Tap・Tap・t7
1 If the value of equation (7) is “true”, then equation (5) is better than equation (6
), the approximation of Y, -Yx, I, = I is more accurate than the approximation of YC''YN, IC''IN. At this time, it is expected that the approximation of equations (2) and (4) is that equation (2) holds true more accurately, and that the output of means 16 is more accurate than the output of means 17. , with means 16 as the first candidate,
It is better to correct the data by using the means 17 as the @2 candidate.

Of course, we are making judgments, F, K, C',
If one or more of the N pixels contains error data, there is a possibility that the determination result of equation (7) is incorrect.

In this case, of course, the error flags of each pixel used in the calculations in the generating means 16 and 17 are changed, and if there is an error in these, the generated corrected data is not used and is replaced by a lower order data. Since the candidate is selected, regardless of the output of the determining means 1B, the generating means 16 or 1
Only one of 7 is the first candidate.

He will be selected regardless of the second choice.

Generation means 16. If the data generated by the generation means 17 both contain errors, the first and second candidates are not used, and a lower-ranking candidate may be selected. It can be generated using the calculated formula.

etc.

All of these are error data n (having the property of y+t)
phantom and have other properties (Sukwachi, Y+Q,
)'-Q, Y-1 properties) Using five data, (1'+Q)+()'1)-()'-1)...
・・・・・・・・・・・・・・・＋9+ calculation is performed, and even if it is limited to the 15 pixels shown in Figure 2,
There are 3x5x4=56 combinations. Also, if Y-1 is the average value of two Y-1 samples, H=B0P−-(F+K) ・・・・・・・・・・・・
・・・・・・・・・・・・・・・3X3X4 such as Q1
There are C,=54 combinations. The expression fil and the expression (3
) is also one of these combinations.

Also, in addition to this, or etc! It can also be generated by a circuit formed according to the tt formula. These are the average of one or two pieces of data having the same property as the error data H (having the property of Y+1).

Among all the calculation formulas mentioned above, from experience, the formula fil
and equation (3) are known to perform the best interpolation. This is because Equation (1) and Equation (31) generate interpolated data from data closest to the error data H, and the calculation result of the expressions and the center of gravity of the error data H coincide.

According to this embodiment, when both Equation (11) and Equation (3) are valid as interpolation data, the horizontal correlation and vertical correlation can be compared using Equation (1) to perform interpolation with higher accuracy. , the 1iIII element (F and K or C
and N) are also included in Equation (11 or Equation (2)), and even if error data exists in the vicinity of H in addition to H, and Equation (7) makes an incorrect determination, , the interpolation result has
It has the characteristic that it is unlikely to have any negative effects.

・It is possible to consider other methods for determining horizontal and vertical, but considering the small influence of #h-& where the formula misjudged due to incorrect data, we decided to use this method. In the case of the embodiment, equation (7) is most suitable.

〔Effect of the invention〕

According to the present invention, interpolation can be performed by increasing the priority of interpolation data generated from pixels with stronger correlation due to the correlation between pixels in the vicinity of erroneous data, so that interpolation can be performed with higher precision.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a schematic diagram showing a pixel arrangement on a television screen. Means for generating corrected data by using more data in the horizontal direction Means for generating corrected data by using more data in the vertical direction Means for detecting the strength of correlation in the horizontal direction and the vertical direction

Claims (1)

[Claims] 1. If certain sample data in the digital video signal obtained by sequentially sampling and quantizing the video signal at a frequency four times the color subcarrier is erroneous or missing, In a video signal correction device that creates alternative data, correlation detection means (18) detects the strength of horizontal correlation and vertical correlation of sample data near error data.
), a first generating means (16) for generating corrected data by using more data in the horizontal direction near the error data, and a first generating means (16) for generating corrected data by using more data in the vertical direction near the error data. 2 generating means (17) and the output of the correlation detecting means (18), the above means (
16) and means for changing the priority order of the output data of the means (17).