KR0126809B1 - Horizontal and vertical correlation detector for y/c separator - Google Patents

Abstract

The present invention relates to a horizontal vertical correlation detector for a brightness signal and color signal separating device which determines an output of horizontal and vertical correlation processing by determining a color signal and a brightness signal in response to a result from determination of a video signal's code, thus preventing dot interruption and cross color problems.

Description

Horizontal and Vertical Correlation Detector of Luminance and Color Signal Separators

1 is a block diagram of a conventional luminance signal and color signal separation device;

2 is an embodiment of the vertical correlation processing unit of FIG.

3 (a) and (b) are input / output characteristics of FIG.

4 is an embodiment of the horizontal correlation processing unit of FIG.

Figure 5 (a) ∽ (a) is the input and output characteristics of FIG.

6 is a block diagram showing an embodiment of a horizontal vertical correlation detector of a luminance signal and color signal separation device according to the present invention;

7 is a diagram for explaining the sign of a luminance signal, a color signal, and an image signal;

8 (a) (b) is an input / output waveform diagram of each part of FIG.

* Explanation of symbols for the main parts of the drawings

4a, 4b: 1st, 2nd, 1 / 2Fsc delay part 4c: 0 level output part

10,20: first and second 1H delay unit 30: band pass filter unit

40: correlation processing unit 41: zero comparison unit

42: 2's complement part 43: side line value comparison part

44,45: vertical and horizontal code comparison unit 46: zero output unit

50: time delay unit ADD1, ADD2: adder

SUB1: Subtractor MIN1∽MIN5: Minimum value calculator

MAX1∽MAX5: Maximum value calculatorINV1, INV2: Inverter

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a luminance signal and color signal separation device in the field of digital video signal processing. More specifically, dot interference and cross color phenomenon occurring when a composite video signal is separated into a luminance signal and a color signal. It relates to a horizontal and vertical correlation detector of the luminance signal and the color signal separation unit to remove the.

In general, in order to increase the resolution in the S-VHS method, the frequency of the luminance signal needs to have a broadband of 5 MHz or more. For this reason, the color signal (3.58 MHz ± 500 MHz) is included in the band of all luminance signals. Therefore, when attempting to record a composite video signal such as a conventional television broadcast in the S-VHS system, it is necessary to completely separate the luminance signal and the color signal according to the high-performance luminance signal and the color signal separation device.

Therefore, the 2 line logic comb filter that separates the luminance signal and the color signal by using the input composite video signal and the 1H (1 horizontal scanning period) delayed video signal is used to change the vertical direction of the color signal. 3, which separates the luminance signal and the color signal by using a composite video signal (hereinafter referred to as a video signal), a 1H delayed video signal and a 2H delayed video signal due to poor reproducibility and severe cross color or dot interference. A line logic comb filter has been introduced, an example of which is shown in FIG.

On the other hand, the dot obstruction phenomenon is a phenomenon in which a luminance signal is alive and appearing in the color signal output, and a white or black dot appears in the middle of the screen, and a cross color phenomenon is a phenomenon in which the intermediate color is output instead of a desired color.

FIG. 1 is a block diagram of a conventional luminance signal and color signal separation device. The composite image signal b and the second 1H delay unit 1H delayed by the input image signal a and the first 1H delay unit 10 are shown in FIG. The composite video signal c delayed by 2H by (20) is filtered by the band pass filter unit 30 to obtain a range from 3.08 MHz to 4.08 MHz.

The image signal passing through the band pass filter unit 30 is output as a color signal C through the correlation processing unit 40, and at the same time, the image signal of the 1 line delayed by the 1H band is the band pass filter unit. The time delayed by the time delay unit 50 while passing through the 30 and the correlation processing unit 40 is input to the subtractor SUB1 and subtracted from the color signal C output from the correlation processing unit 40 (Y + CC). ) The luminance signal Y is output.

On the other hand, the correlation processing unit 40 is a vertical correlation processing unit for determining the correlation by sampling three vertically parallel points on the screen, and a horizontal correlation processing unit for further attenuating the luminance signal components contained in the color signal separated by the vertical correlation processing unit. In the case of Sony Japan, it is as follows.

First, as shown in FIG. 2, the vertical correlation processing unit includes an inverter INV1 for inverting the image signal b delayed by the first 1H delay unit 1, an input image signal a, and the inverter INV1. A maximum value calculator MAX1 for obtaining a maximum value between the phase-inverted 1H delayed video signal b 'and a phase-inverted 1H delayed video signal b' and a 2H delayed video signal c '. The maximum value calculator MAX2 for obtaining the maximum value of the maximum value, the minimum value calculator MIN1 for obtaining the minimum value between the video signal a and the phase shifted 1H delayed video signal b ', and the phase inverted b. A minimum value calculator (MIN1) for obtaining a minimum value between '), a minimum value calculator (MIN2) for obtaining a minimum value between a phase-inverted 1H delayed video signal (b') and a 2H delayed video signal (c), and The minimum value calculator MIN3 for obtaining the minimum value of the outputs of the maximum value calculators MAX1 and MAX2 and the maximum value of the minimum value calculator MIN1 and MIN2 are obtained. And an adder ADD1 for adding and outputting the outputs of the minimum value calculator MIN3 and the maximum value calculator MAX3.

The operation of the vertical correlation processing unit configured as described above is as follows.

First, the 1H delayed video signal b is phase-inverted through the inverter INV1 and input to the input video signal a and the maximum value calculator MAX1 to be 1H delayed in phase with the input video signal a. The maximum value of the video signal b 'is output. The inverting of the 1H delayed video signal b through the inverter INV1 is performed so that the phase of the color signal is changed by 180 degrees for each 1H according to the NTSC method.

The phase-inverted 1H delayed video signal b 'is input to the 2H delayed video signal c and the maximum value calculator MAX2 to calculate the maximum value, and the maximum value calculator MAX1, ( The output of MAX2) is input to the minimum value calculator (MIN3) to output the minimum value.

In addition, the 1H delayed video signal b ', which is inverted in phase with the input video signal a, is input to the minimum value calculator MIN1, and the 2H delayed signal with the phase inverted 1H delayed video signal b'. The video signal c is input to the minimum value calculator MIN2 and the minimum value is calculated, and the outputs of the minimum value calculators MIN1 and MIN2 are input to the maximum value calculator MAX3 and the maximum value is output. .

The minimum and maximum value outputs of the minimum value calculator MIN3 and the maximum value calculator MAX3 are input to the adder ADD1, and are added and output. The output signal is a luminance signal from an input image signal using vertical correlation. Is a color signal from which.

However, the vertical correlation detection unit configured as described above, in the case of the dot interference phenomenon occurring in the inclined line portion of high luminance and the color signal of the center line or the color signal of the upper and lower lines as shown in FIG. 3 (a) and (b) It is not possible to completely prevent the cross color phenomenon that occurs, the conventional problems still appear.

On the other hand, the horizontal correlation processing unit for further attenuating the luminance signal components included in the color signal separated by the vertical correlation processing unit is configured as shown in Figure 4, the 1H delayed video signal (b) of the color signal subcarrier (Chroma Sub Carrier) A first 1/2 Fsc delay section 4a for delaying by a half cycle of frequency (3.58 MHz), an inverter INV2 for phase-inverting the output of the first 1/2 Fsc delay section 4a, and the first 1 / A second 1 / 2Fsc delay section 4b for delaying the output of the 2Fsc delay section 4a to 1 / 2Fsc again, a 1H delayed video signal b, a signal e through the inverter, and the second 1 / The minimum value calculator MIN4 for obtaining the minimum value between the signals f through the 2Fsc delay unit 4b, and the maximum value detector MAX4 for obtaining the maximum value between the signals b, e, and f. And a maximum between the zero level output section 4c for outputting zero level and the output g of the minimum value calculator MIN4 and the output of the zero level output section 4c. The maximum value calculator MAX for obtaining the minimum value, the minimum value calculator MIN5 for obtaining the minimum value between the output h of the maximum value calculator MAX4 and the output of the zero-level output unit 4c, and the maximum value. The adder ADD2 adds the outputs i and j of the calculator MAX5 and the minimum value calculator MIN5.

In the horizontal correlation processing unit configured as described above, the input signal is a 1H delayed video signal (b), which is input to the first 1/2 Fsc delay unit 4a and is delayed by half a period of the color signal subcarrier frequency. The signal is input to the second 1/2 Fsc delay unit 4b and delayed by a half period of the color signal subcarrier frequency.

The output signal of the first 1/2 Fsc delay unit 4a is phase-inverted by the inverter INV2 to become a signal having a phase as shown in FIG. 5 (b). In addition, the 1H delayed video signal b and the delayed signal e of the phase signal after being delayed by a half cycle of the color signal subcarrier frequency and the delayed signal f by one cycle of the color signal subcarrier frequency are respectively the minimum value calculator MINn4. And the maximum value calculator MAX4 are output as signals as shown in FIG. 5 (d) and (e).

The output signals g and h of the minimum value calculator MIN4 and the maximum value calculator MAX4, together with the outputs of the zero-level output section 4c, respectively, the maximum value calculator MAX5 and the minimum value calculator ( MIN5) is input and the maximum value and the minimum value are selected and output as a signal as shown in Fig. 5 (bar), (g), the maximum and minimum value signals (i), (j) is input to the adder (ADD2) It is added and output as a color signal from which the luminance signal has been removed.

However, as shown in FIG. 5, the horizontal correlation processing unit can reduce the high component component of the luminance signal inclined in accordance with the horizontal correlation, while the edge component of the color signal is lost. Therefore, the horizontal resolution of the color signal is slightly degraded.

That is, in the conventional luminance signal and color signal separation device, the vertical correlation process reduces dot interference and cross color phenomena, and the horizontal correlation process further reduces dot path, but still causes dot interference and cross color phenomena, resulting in deterioration of image quality. Problems exist.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to determine the sign of an image signal and to determine the output of horizontal and vertical correlation processing by judging it as a color signal and a luminance signal according to the result of the determination, thereby preventing dot interference and cross. The present invention relates to a horizontal and vertical correlation detector of a luminance signal and a color signal separation device that eliminates color phenomenon.

A feature of this invention for achieving this object is that the video signal input by the first and second 1H delay units is delayed, and the band pass filter unit band-pass filters the signal around 3.58 MHz, and then the correlation processing unit. A luminance signal and a color signal separation device for separating luminance and color signals by vertically and horizontally correlating at each other, the correlation processing unit comprising: a zero comparison unit to determine whether a digital data value of an inputted 1H delayed video signal is 0; Connected to a zero comparator, and if the output of the zero comparator is not zero, a two's complement that takes two's complement of the digital data value of the video signal input to the zero comparer and a two's complement And a side line value determining unit determining whether the value of the input video signal and the 2H delayed video signal line is 0, and the side line value determining unit. If the value of the input video signal and the 2H delayed video signal line is not 0, the vertical code for judging the 1H delayed video signal line and the sign of both side lines and recognizing the luminance and color signals A sign of the 1H delayed video signal line when the value of the input video signal and the 2H delayed video signal line are both 0, which is connected to a comparator and the side line value determining unit. And a horizontal code comparator for recognizing the luminance signal and the color signal, and a vertical and horizontal code comparator, and the value of the 1H delayed video signal is 0 according to the luminance and color signal recognition results of the vertical and horizontal code comparator. And a horizontal and vertical correlation detector of a luminance signal and color signal separation device comprising a zero output unit for outputting.

Hereinafter, a preferred embodiment of a horizontal vertical correlation detector of a luminance signal and color signal separating apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 6 is a block diagram showing an embodiment of a horizontal and vertical correlation detector of a luminance signal and a color signal separation device according to the present invention, and compares zero to determine whether a digital data value of an input 1H delayed image signal (b) is 0. FIG. When the output of the zero comparison unit 41 is not 0, the two complementing unit 42 which takes two's complement of the digital data value of the 1H delayed video signal b is connected to the unit 41. do.

In addition, a side line value determination unit 43 for determining whether the input video signal and the 2H delayed video signal lines 0H and 2H have a value of 0 is connected to the complementary part 42 of the two. In the value determining unit 43, if the value of the input video signal and the 2H delayed video signal lines 0H and 2H are not 0, the 1H delayed video is determined by the side line value determining unit 43. Judgment results of the vertical code comparator 44 and the side line value judging unit 43 which determine the signs of the signal line 1H and the side lines 0H and 2H and recognize them as luminance signals and color signals. And a 2H delayed video signal line (0H), when the value of (2H) is both 0, the horizontal code comparison unit 45 to determine the sign of the 1H delayed video signal line (1H) to recognize as a luminance signal and a color signal Is connected.

In addition, the vertical and horizontal code comparison units 44 and 45 have values of the 1H delayed video signal b according to the luminance and color signal recognition results of the vertical and horizontal code comparison units 44 and 45. The zero output unit 46 for outputting 0 as is connected.

7 is a view for explaining the sign of the luminance signal, the color signal and the image signal, the luminance signal is represented in the form of dots, the color signal is represented in the form of a sine wave, and the sign of the image signal based on the reference line, that is, zero level line The upper part is + and the lower part is-.

8 (a) (b) is an input / output waveform diagram of each part of FIG. 6, which shows outputs for input signals in various cases, and according to the present invention, in a horizontal vertical correlation detector of a luminance signal and a color signal separation device, It shows the process of eliminating dot interference and cross color phenomenon.

The present invention configured as described above separates the luminance signal and the color signal by processing the image signal passing through the band pass filter unit 30 in the conventional luminance signal and color signal separation device as shown in FIG. The 1H delayed video signal b of the video signals passed through 30 is input to the zero comparator 41.

The zero comparator 41 determines whether the digital data value of the 1H delayed video signal is an approximation of 0, and outputs an output of correlation processing when the approximation is 0. If not 0, 2's complement is output to 2's complement section 42 to output the 1H delayed video signal b. As shown in FIG. 8, the video signal passed through the two complementing unit 42 is inverted by the 1H delayed video signal line 1H. In addition, the reason for taking two's complement here is to eliminate this phase difference in the NTSC system because there is a 180 degree phase difference in every line.

The 2H complemented 1H delayed video signal is input to the side line value determiner 43, and the side line value determiner 43 receives the input image signal a and A 2H delayed video signal c is also input.

Accordingly, the side line value determiner 43 determines whether the input input video signal and the 2H delayed video signal lines 0H and 2H are all zero. As a result of this determination, when the values of the two lines (0H) and (2H) both have a value of 0 (e.g., (d) of FIG. 8), the image signal b of the 1H delayed line is a horizontal code comparison unit 54. In the case where a line is inputted as a non-zero value (for example, bar 8 of FIG. 8), the vertical sign comparator 44 determines the luminance signal and the color signal.

The modifier code comparator 44 judges that the 1H delayed video signal line 1H is the same as the color signal if it determines the signs of both the lines 0H and 2H. ) Outputs the value of the 1H delayed video signal b to 0. The reason why the value of the 1H delayed video signal b is output as 0 is to prevent the luminance signal from being alive in the color signal component. Therefore, in the case of the inclined line portion as in the case of FIG. 8 (bar), the luminance signal component is not alive in the color signal component, and the dot interference phenomenon is completely eliminated.

As shown in Fig. 7, the horizontal code comparison section 45 has the sign of the color signal +-+-. It is determined whether the value currently input is correct by the above order, and if it is correct, it is recognized as a color signal and the value is correlated output.If it is wrong, that is, if the sign of the color signal is irregular, it is recognized as a luminance signal. The output unit 46 outputs the value of the video signal line 1H delayed by 1H as 0. Therefore, even when both side lines 0H and 2H have a value of 0, as shown in FIG. 8 (D), the amplitude of the color signal is not reduced to 1/2 so that no cross color phenomenon occurs. It does not occur.

As described above, the present invention compares the sign of the line of the 1H delayed video signal with the line of the undelayed video signal and the line of the 2H delayed video signal when the luminance signal and the color signal are separated. By eliminating the cross color phenomenon by eliminating the cross-correlation process according to the regularity of the code by comparing the code before and after the 1H delayed line, it is possible to completely eliminate the dot obstruction and the cross clutter phenomenon, thereby obtaining better image quality. have.

Claims (3)

The video signal input by the first and second 1H delay units 10 and 20 is delayed, and the band pass filter unit 30 performs band pass filtering on a signal around 3.58 MHz, and then the correlation processor 40 In the luminance signal and the color signal separation device for separating the luminance signal and the color signal by vertical and horizontal correlation processing, the correlation processing unit 40, the zero to determine whether the digital data value of the input 1H delayed video signal is 0 2 is connected to the comparator 41 and the zero comparator 41, and when the output of the zero comparator 41 is not 0, two of the digital data values of the video signal input to the zero comparator 41 are displayed. A side line value determination unit 43 connected to the two's complement 42 and the two's complement 42 that determines whether the value of the input video signal and the 2H delayed video signal line is 0. And, it is connected to the side line value determiner 43, this side line value plate If the value of the input video signal and the 2H delayed video signal line is not 0, the end 43 judges the sign of the 1H delayed video signal line and both side lines and recognizes the signals as luminance signals and color signals. Is connected to the sign comparator 44 and the side line value determiner 43, and the value of the input video signal and the 2H delayed video signal line are both 0 as a result of the determination of the side line value determiner 43; And a horizontal code comparator 45 for determining a sign of a 1H delayed video signal line and recognizing the signal as a luminance signal and a color signal, and the vertical and horizontal code comparators 44 and 45, respectively. The horizontal and vertical correlation between the luminance signal and the color signal separation device comprising a zero output unit 46 which outputs the value of the 1H delayed video signal to 0 according to the luminance signal and the color signal recognition result of the code comparison unit 44 or 45. Detector. 2. The display apparatus of claim 1, wherein the vertical code comparator 44 judges the codes of the 1H delayed video signal lines and the side lines, and judges them as color signals if the codes are the same, and determines the luminance signals if the codes are different. Horizontal and vertical correlation detector of color signal separator. The apparatus of claim 1, wherein the horizontal code comparator 45 judges the code of the 1H delayed video signal line and judges that the code is a color signal if the code is regular, and determines the luminance signal if the code is irregular. Horizontal vertical correlation detector.