JP2733175B2 - Composite video signal correlation detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a correlation detecting apparatus necessary for separating a composite video signal of the NTSC system into a luminance signal and a chrominance signal in two dimensions and performing a filtering process for band compression. It is about.

[0002]

2. Description of the Related Art In recent years, adaptive signal processing has been widely used for signal processing for filtering a composite video signal in two dimensions. However, there is little technical progress in the correlation detection device required at that time. This is because the composite video signal has a relationship in which the luminance signal and the carrier chrominance signal are interleaved at the line frequency, so that the rule of horizontal and vertical correlation of the normal video signal cannot be used as it is.

As a conventional composite image signal correlation detecting apparatus, there is one disclosed in, for example, Japanese Patent Application Laid-Open No. Sho 60-134587. Hereinafter, a conventional composite video signal correlation detecting apparatus will be described.

FIG. 14 is a block diagram of a conventional composite video signal correlation detecting apparatus. In FIG. 14, an input terminal 1 is an input terminal for inputting a composite video signal, and is connected to the 1H delay circuits 2 and 3. The 1H delay circuit 2 delays the input composite video signal by 1H (H is the scanning period of the horizontal scanning line), and the 1H delay circuit 3 further delays by 1H. Delay circuit 4
Delays the output signal of the 1H delay circuit 2 by T (T is the carrier cycle of the carrier color signal). The delay circuits 5 and 6 convert the output signal of the 1H delay circuit 3 and the input signal of the input terminal 1 into T /
It is delayed by two. The subtraction circuit 7 outputs a difference signal between the output signal of the 1H delay circuit 2 and the output signal of the delay circuit 4, and the output is given to the absolute value circuit 9.
The subtraction circuit 8 outputs a difference signal between the output signal of the delay circuit 5 and the output signal of the delay circuit 6, and the output is supplied to the absolute value circuit 10. The absolute value circuits 9 and 10 take the absolute value of the difference signal between the outputs of the subtraction circuit 7 and the subtraction circuit 8, respectively. The comparison circuit 11 compares the levels of the output signals of the absolute value circuits 9 and 10, and outputs a comparison result from an output terminal 12.

[0005] The operation of the conventional composite video signal correlation detecting apparatus configured as described above will be described with reference to FIG. FIG. 4 is a schematic diagram for explaining the operation of the conventional composite video signal correlation detection apparatus shown in FIG. 14 and a correlation detection apparatus according to an embodiment of the present invention described later.

First, the composite video signal input to the input terminal 1 is delayed by the 1H delay circuits 2 and 3 and the delay circuits 4, 5 and 6, so that the composite video signal is 4H apart from the pixel of interest by 1H vertically and T / 2 horizontally. The pixel signals are synchronized. That is, in FIG. 4, the composite video signal is considered as a signal of 9 pixels in an area of 3 pixels separated by 1H in the vertical direction and 3 pixels separated by T / 2 in the horizontal direction on the image. The pixel signals are converted into S11, S12, S13, S2 as shown in FIG.
1, S22, S23, S31, S32, and S33.
When the pixel of interest is S22, the horizontal S2
Considering four pixel signals 1 and S23 and S12 and S32 in the vertical direction, these four pixel signals are four pixels in which the carrier of the carrier chrominance signal is in phase. When the pixel signal input to the input terminal 1 is S33, the output of the 1H delay circuit 2 is S23, and the output of the delay circuit 4 is S21.
However, S12 is output to the output of the delay circuit 5 and S32 is output to the output of the delay circuit 6, so that the four pixel signals can be synchronized. Then, the difference between S21 and S23 is calculated by the subtraction circuit 7, and the absolute value of the difference signal is calculated by the absolute value circuit 9, thereby calculating the degree of non-correlation of the pixel of interest S22 in the horizontal direction. Similarly, S12 and S3 in the subtraction circuit 8
2 and the absolute value circuit 10 calculates the absolute value of the difference signal to calculate the degree of non-correlation in the vertical direction with respect to the target pixel S22. The level of the horizontal decorrelation strength and the vertical decorrelation strength are compared by the comparison circuit 11 to detect the more highly correlated directions in the horizontal and vertical directions. The result can be output to the output terminal 12.

[0007] Here, the correlation detector shown in FIG. 14 uses the j-th pixel signal S (i, j) of the i-th line as a target pixel, and 画素 S (i−1, j) −S (i + 1, j). )｝ And ｛S
The horizontal-vertical correlation calculating means 100 calculates the horizontal-vertical correlation by comparing the magnitudes of the absolute value levels of (i, j-1) -S (i, j + 1)}.

[0008]

However, in the above-described conventional configuration, the time difference between S21 and S23 in FIG. 4 is T, the time difference between S12 and S32 is 2H, and the pixels are spatially separated by 2 pixels each. For this reason, there is a disadvantage that steep changes in the horizontal and vertical directions cannot be reliably detected. For this reason, it is only possible to detect a simple pattern correlation such as which one of a rough horizontal correlation and a vertical correlation is stronger.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems. Correlation detection of a composite video signal capable of reliably detecting a steep change portion in the horizontal and vertical directions and capable of detecting correlations of various complicated patterns. It is intended to provide a device.

[0010]

According to a first aspect of the present invention, a pixel of interest of an input composite video signal is set to T / 2.
(2m + 1) × (2n + 1) pixel signals within an area of upper and lower m (m is a positive integer) pixels and left and right n (n is a positive integer) pixels sampled for each (T is a carrier cycle of a carrier color signal) And weighted addition of all (2n + 1) pixel signals of the pixel lines in each row of the synchronized pixel signals, and (2n +
1) The level of each of the pixel signals is compared, and the level is calculated by horizontal direction calculating means for calculating all the pixel signals of the upper and lower 2m lines excluding the target pixel line, and the horizontal direction calculating means. Horizontal pattern comparing means for comparing the 2m × (2n + 1) large and small data patterns with a predetermined pattern; and correlation determining means for determining a correlation based on the horizontal pattern comparing means. Things.

According to a second aspect of the present invention, an upper and lower m (m is a positive integer) sampled every T / 2 (T is a carrier wave period of a carrier color signal) with respect to a pixel of interest of an input composite video signal. ) Line, left and right n (n is a positive integer) pixel area (2m +
1) × (2n + 1) pixel signals, and a delay unit for synchronizing the pixel signals, and (2m +
1) all the pixel signals are weighted and added, the level of each of the (2m + 1) pixel signals in the column is compared with the addition result, and the result is compared with the left and right 2n columns excluding the pixel column of interest. Vertical direction calculating means for calculating all pixel signals, and (2m +
1) A vertical pattern comparing means for comparing × 2n large and small data patterns with a predetermined pattern, and a correlation determining means for performing a correlation determination based on an output of the vertical pattern comparing means. Things.

According to a third aspect of the present invention, an upper and lower m (m is a positive integer) sampled at every T / 2 (T is a carrier wave period of a carrier chrominance signal) with respect to a pixel of interest of an input composite video signal. ) Line, left and right n (n is a positive integer) pixel area (2m +
1) a delay means for synchronizing the (2n + 1) pixel signals, and weighting addition of all (2n + 1) pixel signals of the pixel lines of each row among the synchronized pixel signals; Horizontal operation means for comparing the level of each of the (2n + 1) pixel signals of the row and calculating the level of all the pixel signals of the upper and lower 2m lines excluding the pixel line of interest; Of the pixel signals
All (2m + 1) pixel signals of each pixel column are weighted and added, the level of each of the (2m + 1) pixel signals of the column is compared with the addition result, and the result is excluded from the pixel column of interest. A vertical direction calculating means for calculating all the pixel signals of the left and right 2n columns, and a horizontal pattern comparison for comparing 2m × (2n + 1) large and small data patterns obtained by the horizontal direction calculating means with a predetermined pattern. (2m) obtained by means of
+1) × 2n large / small data patterns are compared with a predetermined pattern, a vertical pattern comparing means, and a correlation determining means for performing a correlation determination based on outputs of the horizontal pattern comparing means and the vertical pattern comparing means. It is characterized by the following.

[0013]

According to the present invention, in the above-described configuration, in the synchronized pixel signals, the pixel signals of all lines except for the pixel line of interest are calculated to obtain a large and small data pattern in the horizontal direction. Further, the pixel signals of all the pixel columns except the pixel column of interest are calculated to obtain a large / small data pattern in the vertical direction. Then, by comparing (matching) these large and small data patterns with patterns defined by various conditions, correlations in various cases can be detected.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. 1 to 3 show block diagrams of a composite video signal correlation detecting apparatus according to a first embodiment of the present invention. In FIG. 1, the same portions as those in the above-described conventional example are denoted by the same reference numerals, and detailed description is omitted. A composite video signal is input to an input terminal 1, and a T / 2 delay circuit 6, T
A / 2 delay circuit 21 is cascaded. Also, a T / 2 delay circuit 2 via a 1H delay circuit 2 for delaying an input signal by 1H.
2, 23 are cascaded. Further, the 1H delay output is applied to the 1H delay circuit 3. The 1H delay circuit 3 further delays this signal by 1H, and its output is supplied to cascaded T / 2 delay circuits 5 and 24. These outputs are (2m + 1) in an area of m lines (m = 1 in this example) vertically and n pixels (n = 1 in this example) on the left and right, assuming that the output pixel of the T / 2 delay circuit is the target pixel. × (2n +
The delay means 20 for synchronizing the pixel signals in 1) is configured.

As shown in FIG. 2, the output of the input terminal 1 and the outputs of the T / 2 delay circuits 6 and 21 are supplied to comparison circuits 31 to 33 of the horizontal operation unit 30, respectively. It is also provided to the weighting circuit 34. 1
The outputs of the H delay circuit 3 and the outputs of the T / 2 delay circuits 5 and 24 are respectively output from the comparison circuits 36 to 38 of the second horizontal operation unit 35.
, And all of them are also supplied to the weighting addition circuit 39. On the other hand, as shown in FIG. 3, the outputs of the T / 2 delay circuits 21, 23, and 24 are respectively supplied to the comparison circuits 41 to 43 of the vertical operation unit 40, and all of them are also supplied to the weighting addition circuit 44. ing. The outputs of the 1H delay circuits 3 and 2 and the input terminal 1 are respectively supplied to the vertical operation unit 45.
, And all of them are also applied to the weighting and adding circuit 49.

The weighting and adding circuit 34 weights the input signal of the input terminal 1 and the output signal of the delay circuit 21 around the output signal of the delay circuit 6 so that the total is 1 at the maximum, for example, 1/2, 1 respectively. / 4 and 1/4 are added to extract low-frequency component signals. The output of the weighting and adding circuit 34 is given as a reference signal to the comparing circuits 31 to 33, and the comparing circuits 31 to 34 output the compared large and small data. Similarly, the weighting addition circuit 39 of the horizontal direction calculation unit 35 adds the output signal of the 1H delay circuit 3 and the output signal of the delay circuit 24 with the same weighting around the output signal of the delay circuit 5 to obtain a low-frequency signal. To extract the components of The added output is given as a reference signal to the comparison circuits 36 to 38, and a magnitude signal is output from each of the comparison circuits to the horizontal pattern comparison circuit 50. Similarly, the weighting and adding circuit 44 of the vertical operation unit 40 adds the output signals of the T / 2 delay circuits 21 and 24 with the same weighting around the output signal of the T / 2 delay circuit 23, and compares the added signals with the comparison circuits 41 to 41. Give to 43. The weighting and adding circuit 49 adds the output signal of the 1H delay circuit 2 to the input terminal 1 and the output signal of the 1H delay circuit 3 with the same weighting around the output signal of the 1H delay circuit 2, and provides the same to the comparison circuits 46 to 48 centering on the low frequency component. Comparison circuits 41 to 43, 46
Similarly, .about.48 compare the input signal with the added output, and the discrimination output is given to the vertical pattern comparing circuit 51.

The horizontal pattern comparison circuit 50 includes a comparison circuit 31
By comparing large and small patterns of .about.33 and 36.about.38 with a predetermined specific pattern, various correlations in the horizontal direction are detected. The vertical pattern comparing circuit 51 detects various correlations in the vertical direction by comparing large and small data patterns of the comparing circuits 41 to 43 and 46 to 48 with a predetermined specific pattern. These outputs are output to the correlation determination circuit 52.
Given to. The correlation judging circuit 52 is an overall judging circuit for judging the integrated correlation judgment result from these comparison results and outputting the result from the output terminal 53.

The operation of the apparatus for detecting correlation of a composite video signal according to the present embodiment thus constructed will be described. FIG. 4 is a schematic diagram for explaining the operation of the present embodiment. First, the composite video signal input to the input terminal 1 is applied to 1H delay circuits 2 and 3
And 1H in the vertical direction on the image in FIG. 4 by being delayed by the delay circuits 6, 21 to 23, 5, and 24.
3 lines separated by T / 2 in the horizontal direction
The signals of all nine pixels in the pixel column area are synchronized. That is, if the pixel signal input to the input terminal 1 is S33, the output of the 1H delay circuit 2 is S23, the output of the 1H delay circuit 3 is S13, and the output of the delay circuit 6 is S3.
2 is the output of the delay circuit 21, S31 is
Is output to S22, and the output of delay circuit 23 is output to S21.
However, S12 is output to the output of the delay circuit 5 and S11 is output to the output of the delay circuit 16. Therefore, the nine pixel signals shown in FIG. 4 can be synchronized. Then, the weighting addition circuit 34 weights and adds S33, S32, and S31 to extract a signal of a low-frequency component of the third line in FIG. 4, that is, a signal corresponding to a luminance signal. Then, a signal component corresponding to the luminance signal and S33, 32, 31
Are compared by the comparison circuits 31, 32, and 33, respectively, to obtain a horizontal large / small data pattern of a high-frequency signal including the carrier color signal of the third line in FIG. Similarly, S13, S12, and S11 are weighted and added by the weighting addition circuit 39, and the addition result is compared with S13, S12, and S11.
Are level-compared by comparison circuits 36 to 38, respectively. In this way, a horizontal large / small data pattern of a high-frequency signal including the carrier color signal of the first line in FIG. 4 can be obtained.

In the weighting and adding circuit 44, S31, S2
By weighting and adding 1, S11, a signal of a low-frequency component of the first pixel row in FIG. 4, that is, a signal corresponding to a luminance signal is extracted. Then, a signal component corresponding to the luminance signal and S31, S21, and S11 are compared with the comparison circuits 41 to 41, respectively.
By comparing the levels at 43, the first in FIG.
The vertical data size of the high-frequency signal including the carrier color signal of the pixel column is obtained.

Similarly, S1 is calculated by the weighting addition circuit 49.
3, S23, and S33 are weighted and added, and the levels of the addition result and S13, S23, and S33 are compared by comparing circuits 46 to 48, respectively. A vertical magnitude data pattern of the signal is obtained.

Thereafter, the horizontal pattern comparing circuit 50 compares the horizontal large and small data patterns of the first and third lines obtained by the comparing circuits 31 to 33 and the comparing circuits 36 to 38 with a predetermined specific pattern. By doing so, various horizontal correlations are detected. The vertical pattern comparing circuit 51 compares the large and small vertical data patterns of the first and third pixel columns obtained by the comparing circuits 41 to 43 and the comparing circuits 46 to 48 with a predetermined specific pattern. , Various vertical correlations are detected. Further, the correlation determination circuit 52 obtains a total correlation determination result from the comparison result of the horizontal pattern comparison circuit 50 and the comparison result of the vertical pattern comparison circuit 51.

Next, examples of various correlation detection results based on more specific operations of the horizontal pattern comparison circuit 25 and the vertical pattern comparison circuit 34 in the first embodiment will be described. FIG.
FIG. 4 is a chart illustrating an example of various correlation detection results in the correlation detection device of the first embodiment. FIG. 15 is a chart showing an example of a correlation detection result of the conventional correlation detection device shown in FIG. 6 to 9 are chart diagrams showing the characteristics of the correlation of the normal video signal. 5 to 9 and 1
In all of the charts shown in FIG. 5, the horizontal axis represents the horizontal frequency (f _H ) component of the video signal, and the vertical axis represents the vertical frequency (f _V ) component of the video signal. The color signal carrier frequency corresponds to the portion of the figure f _C of FIG. 8 and FIG. 9, the flat portion of the carrier chrominance signal thus will be the frequency component at the indicated position in the f _C is concentrated. Further, in the flat portion of the luminance frequency, the frequency components are concentrated at the position of the origin (0) of each chart. In a normal video signal, a portion where the vertical frequency component of the luminance signal is higher, that is, a portion of the picture which is fine in the vertical direction on the screen, in other words, a portion where the horizontal correlation of the luminance signal is stronger, is shown by oblique lines in FIG. The frequency component is present in the portion, and the energy is larger in the portion closer to the origin (0). In a normal video signal, a portion where the horizontal frequency component of the luminance signal is higher, that is, a portion having a fine pattern in the horizontal direction of the screen, in other words, a portion where the vertical correlation of the luminance signal is stronger, is a portion indicated by oblique lines in FIG. , The frequency component is present, and the closer to the origin (0), the greater the energy.

Similarly, a portion having a higher vertical frequency component of the carrier color signal at a normal video frequency, ie, a portion of a picture having a large color change in the vertical direction on the screen, in other words, a portion having a stronger horizontal correlation of the carrier color signal. In FIG. 8, the frequency components are present in the shaded portions in FIG. 8, and the energy is higher in the portion closer to f _C in the diagram. Also, in a normal video signal, a higher portion of the horizontal frequency component of the carrier color signal, that is, a portion of a picture having a large color change in the color direction in the horizontal direction on the screen, in other words, a portion of the carrier color signal where the vertical correlation is stronger. In FIG. 9, the frequency component is present in the shaded area,
The energy nearer to _C is higher.

Here, comparing the charts of FIG. 6 and FIG. 9, it can be seen that there are many overlaps between the hatched portions of the two charts. This is because the luminance signal has a fine picture portion in the vertical direction of the screen, that is, a portion where the horizontal correlation of the luminance signal is stronger, and a picture portion where the color change of the carrier color signal is large in the horizontal direction on the screen, that is, the vertical correlation of the carrier color signal. It means that it is difficult to distinguish it from the parts with stronger sex. 7 and 8
Comparing the chart diagrams of the two chart diagrams, there are many overlapping portions indicated by diagonal lines in the two chart diagrams, a portion of a fine pattern in the horizontal direction of the screen of the luminance signal, that is, a portion having a stronger vertical correlation of the luminance signal and a portion of the carrier color signal. This means that it is difficult to distinguish a picture portion having a large color change in the vertical direction on the screen, that is, a portion having a stronger horizontal correlation of the carrier color signal.

FIGS. 5 and 15 are charts showing portions detected by the present embodiment and the conventional correlation detection device, and the portions shown in black are the portions where correlation is detected. The conventional correlation detection device shown in FIG. 14 detects a stronger direction between the horizontal correlation and the vertical correlation, and FIG. 15 shows the detection result by a black mark in a portion where the vertical correlation is stronger than the horizontal correlation. (That is, the portion where the horizontal edge of the image exists is detected.) As can be seen from FIG. 15, the conventional correlation detection apparatus of FIG. 14 is almost dependent on the horizontal and vertical frequencies, and thus the horizontal edge of the color signal. It is impossible to distinguish between the part and the horizontal edge part of the luminance signal. FIG. 5 shows a result of detecting a portion where a horizontal edge portion of a color signal may exist in the present embodiment. Here, in the vertical pattern comparison circuit 51 having the configuration of FIG. 3, the case where the large and small data patterns of the comparison circuits 43, 42, 41 are (large, small, large) is expressed by the following equation (1).

(Equation 1)

Similarly, in the horizontal pattern comparison circuit 50 of FIG. 3, the case where the large and small data patterns of the comparison circuits 36, 37 and 38 are (large, small, large) is expressed by the following equation (2).

(Equation 2) FIG. 5 shows the portion of equation (3) shown below by the correlation determination circuit 52 using a well-known zone plate pattern.

(Equation 3)

This is because when the large and small data patterns of the comparison circuits 43 to 41 and 46 to 48 are (large, small, large, small, large, small) or (small, large, small, large, small, large) The first pixel column in No. 2 has a periodic signal waveform, which means that it is highly possible to include a carrier chrominance signal.
As a result, Equation (3) detects that the first or third pixel column in FIG. 5 has a high possibility of including the carrier color signal, and FIG. 5 shows the color signal in FIG. In the horizontal direction, that is, a portion where there is a high possibility that a horizontal edge portion exists. This is because the fact that the carrier color signal is included in the first pixel row or the third pixel row means that the whole of FIG. 4 is a carrier color signal that has little change in the horizontal and vertical directions, or that the whole of FIG. This is the carrier color signal that is present. If the carrier color signal changes in the vertical direction, it is unlikely that the first pixel row or the third pixel row has a periodic signal waveform. When FIG. 5 is compared with FIGS. 8 and 9, it can be seen that the portion shown in FIG. 9 can be more reliably separated and detected. In this case, the horizontal pattern comparison circuit 50
Is not used.

Although the above-described reference pattern shows an example in which the determination is made only for the first and third pixel columns, the pattern in the horizontal direction may be determined using the pixels in the first or third line. Needless to say.

In the above-described first embodiment, the operation is performed with respect to signals of 9 pixels within an area of 3 lines separated by 1H in the vertical direction and 3 pixel columns separated by T / 2 in the horizontal direction. Although the configuration has been described, even if the number of lines and the number of pixel columns are increased, the same concept can be applied. As the area increases, the circuit scale increases, but it goes without saying that the correlation detection accuracy is improved. In FIG. 10, each pixel in the area of the upper and lower m lines and the left and right n pixels is delayed by the delay unit 60 with respect to the point of interest so that the pixels are synchronized. Each of the outputs is supplied to a horizontal direction calculation means composed of 2m horizontal direction calculation units 61-1 to 61-2m, the same as in FIG. The inside of this block is the same as that shown in FIG. 2, and the output is provided to the horizontal pattern comparison circuit 63. The output of the delay means 60 is supplied to the vertical direction calculation means comprising 2n vertical direction calculation units 62-1 to 62-n as shown in FIG. The output is compared with a reference pattern by a vertical pattern comparison circuit 64. The output of the conventional horizontal / vertical correlation operation means 100 shown in FIG. The correlation determining circuit 65 determines the presence or absence of a correlation based on the output H or V and the output of the horizontal / vertical pattern comparison circuit, for example, using a logical expression as described later.

If m = 1 and n = 2, the detection accuracy can be nearly doubled for pixels in an area of 5 pixel columns in the vertical direction and 3 lines in the horizontal direction.

In the second embodiment, as shown in FIG. 11, a portion where a horizontal edge portion of a color signal may exist is targeted for 15 pixels in an area of 5 horizontal rows of pixels and 3 vertical lines. FIG. 12 shows the result of detecting
It is a chart figure of (a). In this case, the vertical pattern comparison circuit 64 and the correlation determination circuit 65 detect the following equation (4).

(Equation 4) This is the case in FIG. 11 where the first pixel row and the second pixel row include the carrier color signal at the same time, or the fourth pixel row and the fifth pixel row are likely to simultaneously include the carrier color signal. . Therefore, it can be said that FIG. 12A shows a portion where the horizontal edge portion of the color signal is likely to exist in FIG. In the case of FIG. 12A, the detection pattern of FIG.
_The pattern is as if it were compressed to _H , and it can be seen that the detection accuracy is clearly higher than in the case of FIG. This is because the probability of erroneously detecting a high-frequency component of the luminance signal without the color signal shown in FIG. 6 is smaller in the case of FIG. 12A than in the case of FIG.

FIG. 12B shows an AND of the correlation detection result of FIG. 11 and the detection result of the horizontal / vertical correlation detection means 100. Here, when a portion where the vertical correlation is stronger in the conventional detection method is represented by V, the detection of the correlation determination circuit 65 for obtaining the detection result of FIG. 12B is represented by the following equation (5).

(Equation 5) In FIG. 12B, the detection accuracy is further improved as compared with FIG. 12A, and only the horizontal edge portion of the color signal can be detected almost certainly.

FIG. 13 shows a result obtained by adding the result of the determination made by the horizontal / vertical correlation calculating means 100 to the first embodiment. The present embodiment is a result of detecting a portion where neither the horizontal edge nor the vertical edge of the color signal exists, that is, a pattern where the luminance signal component is large and the color signal component is small. In this case, when a portion having a stronger horizontal correlation is represented by H in the conventional detection method (corresponding to a portion shown in white in FIG. 15), the correlation determination circuit 65 detects it as the following expression (6).

(Equation 6) This is because in FIG. 4 the first or third pixel column contains a carrier color signal, and if the vertical correlation is strong, there is a high possibility that a horizontal edge of the color signal exists, and the first line or the third line is not. If the three lines include the carrier color signal and the horizontal correlation is strong, there is a high possibility that a vertical edge of the color signal exists, and the other cases are detected. Comparing FIG. 13 with FIGS. 6 to 9, it can be seen that a pattern portion having a relatively large luminance signal component and a relatively small color signal component can be separated from a reverse pattern portion.

As described above, according to the embodiments of the present invention, the horizontal pattern comparison circuit and the vertical pattern comparison circuit compare with a specific pattern determined by various conditions, thereby detecting a correlation in various complicated cases. Can also be performed with high precision.

[0035]

As described above in detail, according to the present invention, by comparing the large and small data patterns obtained by the vertical operation means and the horizontal operation means with predetermined patterns, the horizontal and vertical directions are obtained. Can be reliably detected even in a portion where the change is abrupt, and correlation detection of various complicated patterns becomes possible.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a delay unit of a composite video signal correlation detection apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a portion of a horizontal direction calculating means of the composite video signal correlation detecting device according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a portion of a vertical direction calculating means of the composite video signal correlation detecting device according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram for explaining the operation of the first embodiment of the present invention and a conventional composite video signal correlation detection device.

FIG. 5 is a chart showing a correlation detection result in the correlation detection device of the first embodiment.

FIG. 6 is a chart diagram (part 1) showing characteristics of correlation of a normal video signal.

FIG. 7 is a chart diagram (part 2) showing characteristics of correlation of a normal video signal.

FIG. 8 is a chart diagram (part 3) showing characteristics of correlation of a normal video signal.

FIG. 9 is a chart (No. 4) showing characteristics of correlation of a normal video signal.

FIG. 10 is a block diagram illustrating an overall configuration of a composite video signal correlation detection device according to a second embodiment of the present invention.

FIG. 11 is a schematic diagram for explaining the operation of the present embodiment.

FIG. 12 is a chart illustrating different examples of correlation detection results according to the present embodiment.

FIG. 13 is a chart showing an example of a correlation detection result according to another embodiment of the present invention.

FIG. 14 is a block diagram showing an example of a conventional composite video signal correlation detection device.

FIG. 15 is a chart showing an example of a correlation detection result of a conventional composite video signal correlation detection device.

[Explanation of symbols]

2,3 1H delay circuit 5,6,21-24 T / 2 delay circuit 20,60 delay means 31-33,36-38,41-43,46-48 comparison circuit 34,39,44,49 weighted addition circuit 30, 35, 61-1 to 61-2m Horizontal direction operation unit 40, 45 62-1 to 62-2n Vertical direction operation unit 50 Horizontal pattern comparison circuit 51 Vertical pattern comparison circuit 52, 65 Correlation determination circuit 63 Horizontal pattern comparison circuit 64 vertical pattern comparison circuit 100 horizontal / vertical correlation operation means

Claims (6)

(57) [Claims] 1. An upper and lower m (m is a positive integer) line and a left and right n (n) sampled at T / 2 (T is a carrier wave period of a carrier color signal) with respect to a pixel of interest of an input composite video signal. Delay means for synchronizing (2m + 1) × (2n + 1) pixel signals in a pixel area, and (2n + 1) pixel signals of a pixel line of each row among the synchronized pixel signals Are weighted and added, the level of each of the (2n + 1) pixel signals in the row is compared with the addition result, and the level is compared with all the pixel signals of the upper and lower 2m lines excluding the pixel line of interest. A horizontal direction calculating means for calculating the horizontal direction, and 2m × (2n +
1) A composite video signal comprising: a horizontal pattern comparing unit that compares a number of large and small data patterns with a predetermined pattern; and a correlation determining unit that determines a correlation based on the horizontal pattern comparing unit. Correlation detection device. 2. An upper and lower m (m is a positive integer) line sampled at every T / 2 (T is a carrier wave cycle of a carrier color signal) and a left and right n (n) for a pixel of interest of an input composite video signal. Is a positive integer) delay means for synchronizing (2m + 1) × (2n + 1) pixel signals in an area of pixels, and (2m +
1) all the pixel signals are weighted and added, the level of each of the (2m + 1) pixel signals in the column is compared with the addition result, and the result is compared with the left and right 2n columns excluding the pixel column of interest. Vertical calculation means for calculating all pixel signals; (2m + 1) × obtained by the vertical calculation means
A composite image comprising: a vertical pattern comparing unit that compares 2n large and small data patterns with a predetermined pattern; and a correlation determining unit that performs a correlation determination based on an output of the vertical pattern comparing unit. Signal correlation detector. 3. An upper and lower m (m is a positive integer) line and a left and right n (n) sampled every T / 2 (T is a carrier cycle of a carrier color signal) with respect to a pixel of interest of the input composite video signal. Delay means for synchronizing (2m + 1) × (2n + 1) pixel signals in a pixel area, and (2n + 1) pixel signals of a pixel line of each row among the synchronized pixel signals Are weighted and added, the level of each of the (2n + 1) pixel signals in the row is compared with the addition result, and the level is compared with all the pixel signals of the upper and lower 2m lines excluding the pixel line of interest. And (2m +) of each pixel column among the synchronized pixel signals.
1) all the pixel signals are weighted and added, the level of each of the (2m + 1) pixel signals in the column is compared with the addition result, and the result is compared with the left and right 2n columns excluding the pixel column of interest. Vertical calculation means for calculating all the pixel signals; and 2m × (2n +) obtained by the horizontal calculation means.
1) horizontal pattern comparing means for comparing the large and small data patterns with a predetermined pattern; and (2m + 1) × obtained by the vertical direction calculating means.
Vertical pattern comparing means for comparing 2n large and small data patterns with a predetermined pattern; and correlation determining means for performing a correlation determination based on outputs of the horizontal pattern comparing means and the vertical pattern comparing means. Characteristic composite video signal correlation detection device. 4. The method according to claim 1, wherein m <n.
The apparatus for detecting a correlation of a composite video signal according to any one of claims 1 to 3. 5. The j-th pixel signal S (i, i,
j) is the pixel of interest, ｛S (i−1, j) −S (i
+ 1, j)} and {S (i, j-1) -S (i, j +
1) horizontal and vertical correlation calculating means for calculating the horizontal and vertical correlation by comparing the magnitudes of the absolute value levels of｝, and the horizontal and vertical correlation data obtained by the horizontal and vertical correlation calculating means is 5. A composite video signal correlation detecting apparatus according to claim 1, wherein the correlation is added to a correlation determining condition of the correlation determining means. 6. The comparison pattern of the horizontal pattern comparison means and the vertical pattern comparison means is a pattern of a row or a column of which the magnitude changes alternately for each pixel column or pixel line. The composite video signal correlation detection device according to any one of the above.