JPH04340891A - Luminance signal color signal separation filter - Google Patents

Abstract

PURPOSE:To obtain an accurate YC separation filter by detecting the correlation of the picture in the vertical direction and the horizontal direction and selecting and outputting the output signals of the luminance signal color signal separation filters of which characteristics are different based on this detection result. CONSTITUTION:An output signal 108 of a horizontal/vertical direction color signal extraction filter 17 is given to a switch circuit 23 also as an output signal 109 of a compensation delay circuit 21. The correlation of the picture in the vertical direction and in the horizontal direction for the remark sample point. When the correlation in the horizontal direction is weak in particular, an output signal 105 is selected of a compensation delay circuit 20 in which an output signal 104 of a vertical direction color signal extraction filter 16 is inputted. When the correlation in the vertical direction is weak in particular, an output signal 107 is selected of a compensation delay circuit 22 in which an output signal 106 of a horizontal direction color signal extraction filter 19 is inputted. In other cases, a switch circuit 23 is switched so that the output signal 109 of the compensation delay circuit 21 in which an output signal 108 of a horizontal/vertical direction color signal extraction filter 17 is inputted may be selected.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a luminance signal and chrominance signal separation filter for separating luminance signals and chrominance signals from, for example, an NTSC composite television signal.

0002

2. Description of the Related Art FIG. 16 is a block circuit diagram of a conventional NTSC luminance signal/chrominance signal separation filter. In the figure, 1 is an input terminal into which an NTSC composite color television signal is input; 2 is an A/D converter that converts the analog composite color television signal into a digital signal; 3;
4 is a first and second one-line delay circuit, 5 is a compensation delay circuit, 6 is a vertical filter, 7 is a bandpass filter, 8, 10
is an output terminal, and 9 is a subtraction circuit.

Next, the operation will be explained. A composite color television signal input to the input terminal 1 is converted into a digital signal 201 by the A/D converter 2 and input to the vertical filter 6 and the first one-line delay circuit 3. 1st
The output 202 of the one-line delay circuit 3 is input to the second one-line delay circuit 4, the compensation delay circuit 5, and the vertical filter 6, and the output is further delayed by one line in the second one-line delay circuit 4. 203 is input to the vertical filter 6.

[0004] The vertical filter 6 is usually composed of a filter called a two-line comb filter, and its output 204 is input to the bandpass filter 7 .

The output 205 of the bandpass filter 7 is derived from the output terminal 8 as a color signal and is also input to one input terminal of the subtraction circuit 9 . The output 206 of the compensation circuit 5 is input to the other input terminal of the subtraction circuit 9. This compensation delay circuit 5 is a circuit for compensating for the delay in the bandpass filter 7. A luminance signal 207 is output from the subtraction circuit 9 and derived from the output terminal 10.

Next, the operation of a conventional filter for an NTSC composite color television signal will be explained.

In the A/D converter 2, the sampling frequency f
The composite color television signal 201 sampled in synchronization with the color subcarrier at s = 4·fsc (fsc is the color subcarrier frequency) forms a two-dimensional array on the screen as shown in FIG. 17. That is, since fsc=(455/2)fH, the phase of the color signal C is inverted by 180° for each line, and four samples are extracted in one cycle. In the figure, Y
indicates the luminance signal, C1 and C2 indicate the color signal, the white circle is Y+C1, the circle with diagonal lines is Y-C1, the white triangle is Y+C2,
The hatched triangle is Y-C2.

[0008] Now, as a symbol representing a delay of one sample and a delay of one line, Z-1 is expressed using Z transformation, respectively.
and Z to the minus El power. Here, Z-1=exp(-j2πf/4fsc). Also, since fsc=(455/2)fH, L=9
It becomes 10.

The vertical filter 6 receives the current input signal 201
, a 1-line delayed signal 202 , and a 2-line delayed signal 20
3, a line support signal 204 that supports each line including the color signal C is extracted. The transfer function Hv (Z) of the vertical filter 6 in this case is

0010

[Math 1] becomes.

That is, the coordinates (m, n
) line support signal Hc (m, n) (204),

[
0012

[Math 2] It will be extracted as.

Since the line support signal 204 also includes the luminance signal Y, the bandpass filter 7 converts the color signal C(m,n) 205, which is a wide-band component, into the line support signal Hc(m,n
)204. The color signal C(m,n) 205 thus obtained is sent to the subtraction circuit 9. The subtraction circuit 9 generates a signal S(m,n)2 obtained by delaying the one-line delayed signal 202 by the compensation delay circuit 5 according to the bandpass filter 7.
The color signal C(m,n) 205 is subtracted from 06 to separate the luminance signal Y(m,n) 207 as follows. Y(m,n)=S(m,n)−C(m,n)

0014
] The transfer function Hh (Z) of the bandpass filter 7 in this case is, for example, Hh (Z) = (-1/32) (1-Z-2)
2 (1-Z-4)2 (1-Z)-8.

[0015]

The conventional luminance signal chrominance signal separation filter combines the characteristics of a vertical filter and a horizontal filter, and separates the luminance signal Y and chrominance signal C using a bandpass filter 7 in both the vertical and horizontal directions. Since we separate
In areas where the brightness and color of the image change rapidly, the brightness signal Y and the color signal C leak into each other, and therefore,
In particular, there have been problems such as deterioration in the quality of reproduced images such as dot interference.

The present invention has been made to solve the above-mentioned problems, and provides a luminance signal that can accurately separate luminance signals and color signals even when sudden changes occur in television signals. The purpose is to obtain a color signal separation filter.

[0017]

[Means for Solving the Problems] A luminance signal/chrominance signal separation filter according to the present invention uses a delay means for delaying a composite video signal sampled at a frequency synchronized with a horizontal scanning frequency one line at a time or two lines at a time. Extract each sample value of the target sample point, the reference sample point, and the reference sample points one or two lines before and after them, and extract the horizontal color signal from the sample value of the target sample point and the sample value of the reference sample point. A first color signal in which a horizontal color subcarrier component is extracted by a filter, and a second color signal in which a vertical color subcarrier component is extracted from each sample value of the sample point of interest and the reference sample point.
An image correlation detection means detects the color signal from each sample value and a third color signal obtained by extracting horizontal and vertical color subcarrier components from each sample value using a horizontal and vertical color signal extraction filter. The color signal is selected based on the correlation in the horizontal direction and the vertical direction detected by the image correlation detection method, and is output as a color signal, and the luminance signal is obtained by subtracting this color signal from the sample value of interest. means for detecting uncorrelated energy DYH of the luminance signal in the horizontal direction from each sample value of the sample point of interest and the reference sample point; The uncorrelated energy DC of the color signal of
horizontal direction color signal non-correlation energy detection means for detecting H; and vertical direction luminance signal non-correlation energy detection means for detecting the non-correlation energy DYV of the vertical direction luminance signal from each sample value of the sample point of interest and the reference point. , the uncorrelated energy DC of the color signal in the vertical direction from each sample value of the reference sample point
Vertical direction color signal uncorrelated energy detection means for detecting V and these uncorrelated energies DYH, DCH, DYV and DCV are compared to determine the magnitude of correlation in the horizontal direction and vertical direction, and based on this determination result, and means for transmitting a signal for selecting a color signal having a high correlation among the first to third color signals.

[0018]

[Operation] The image correlation determining means in this invention selects the first color signal extracted by the horizontal color signal extraction filter when the sample values of the sample point of interest have a weak vertical correlation and a strong horizontal correlation. However, when the sample value of the sample point of interest has a weak correlation in the horizontal direction and a strong correlation in the vertical direction, the second sample value extracted by the vertical color signal extraction filter is used.
Color signal selection is performed in which the third color signal extracted by the horizontal and vertical color signal extraction filters is selected when the third color signal is selected by the horizontal and vertical color signal extraction filters. Therefore, the influence of leakage of luminance signals and color signals to each other channel in areas where the image changes drastically in the vertical direction is reduced, and dot interference can be reduced.

[0019]

【Example】

Example 1. FIG. 1 is a schematic block diagram showing an embodiment of the invention according to claim 1. Reference numeral 11 denotes an input terminal to which an NTSC composite color television signal is applied. 12 is an A/D converter that converts the analog composite color television signal input from the input terminal 11 into a digital signal. 13 is a first one-line delay circuit that inputs the output signal of the A/D conversion 12; 14 is a second one-line delay circuit;
5 is a compensation delay circuit, 16 is a vertical color signal extraction filter, 17 is a horizontal/vertical color signal extraction filter, 18 is an image correlation determination circuit, 19 is a horizontal color signal extraction filter,
20 is a compensation delay circuit, 21 is a compensation delay circuit, 22 is a compensation delay circuit, 23 is a switch circuit, 24 is a switch circuit 2
3 is an output terminal, 25 is a subtraction circuit, and 26 is an output terminal of the subtraction circuit 25.

FIG. 2 is a block circuit diagram showing an embodiment of the image correlation determination circuit 18 in FIG.
7 is a horizontal color signal non-correlation energy extraction circuit; 28 is a horizontal luminance signal non-correlation energy extraction circuit; 29 is a vertical color signal non-correlation energy extraction circuit; 30 is a vertical brightness signal non-correlation energy extraction circuit; 35; 36,3
7 is a comparison circuit, 38 is a judgment circuit, 71, 72, 73a,
73b, 74a, 74b, 77, 78, 79a, 79b
, 80 is a multiplication circuit, 31 is an addition circuit, 82a, 82b,
83 is a maximum value circuit. A/D converter 1 in Figure 1
The output signal 101 of No. 2 is applied to a horizontal luminance signal uncorrelated energy extraction circuit 28, a vertical chrominance signal uncorrelated energy extraction circuit 29, and a vertical luminance signal uncorrelated energy extraction circuit 30 in FIG.

Output signal 1 of first one-line delay circuit 13
02 is applied to a horizontal color signal non-correlation energy extraction circuit 27, a horizontal luminance signal non-correlation energy extraction circuit 28, and a vertical luminance signal non-correlation energy extraction circuit 30.

Output signal 1 of second one-line delay circuit 14
03 is a horizontal luminance signal non-correlation energy extraction circuit 28
and is applied to a vertical color signal non-correlation energy extraction circuit 29 and a vertical luminance signal non-correlation energy extraction circuit 30.

The output signal DCH of the horizontal color signal non-correlation energy extraction circuit 27 is divided into three sides, one of which is connected to the multiplier 7.
2 is multiplied by a constant d and then given to the addition circuit 31, the other is multiplied by a constant f1 by a multiplier 74a and then given to the maximum value circuit 82a, and the other is multiplied by a constant f1 by the multiplier 74a.
After being multiplied by a constant f2 by b, it is applied to the maximum value circuit 82b. The output signal DYH of the horizontal luminance signal non-correlation energy extraction circuit 28 is divided into three parts, one is multiplied by a constant C by a multiplier 71 and then given to the addition circuit 31, and the other is multiplied by a constant e1 by a multiplier 73a. is given to the maximum value circuit 82a, and the other is given to the multiplier 7.
After the constant e2 is multiplied by 3b, the maximum value circuit 82b
given to. The output signal DCV of the vertical color signal non-correlation energy 29 is divided into two parts, one of which is applied to the comparison circuit 36 and the other multiplied by a constant h by the multiplier 78 and then applied to the maximum value circuit 83. The output signal DCV of the vertical luminance signal decorrelation energy extraction circuit is divided into two parts, one of which is given to the comparison circuit 37 and the other to the multiplier 77.
After being multiplied by a constant g, it is applied to the maximum value circuit 83.

The output signal of the adder circuit 31 is applied to the comparator circuit 35 as the first horizontal non-correlation energy DH1. The output signal of the maximum value circuit 82a is converted to a constant m1 by a multiplier 79a as a second horizontally uncorrelated energy DH21.
After being multiplied by , it is applied to the comparator circuit 36. The output signal of the maximum value circuit 82b is the third horizontally uncorrelated energy D.
As H22, the signal is multiplied by a constant m2 by a multiplier 79b and then provided to the comparison circuit 37. The output signal of the maximum value circuit 83 is outputted to the multiplier 8 as the vertically uncorrelated energy DV.
After being multiplied by a constant n by 0, it is applied to the comparison circuit 35.

The comparison circuit 35 compares the first horizontal non-correlation energy DH1 with the vertical non-correlation energy DV multiplied by a constant n, and outputs the output signal 114 when DH1≧n・DV. Set to high level, otherwise set to low level. The comparison circuit 36 compares the vertical color signal uncorrelated energy DCV with the second horizontal uncorrelated energy DH21 multiplied by a constant m1, m1・DH21, and sets the output signal 115 to high when DCV≧m1・DH21. level, and low level at all other times. The comparison circuit 37 compares the vertical luminance signal non-correlation energy DYV with the third horizontal direction non-correlation energy DH22 multiplied by a constant m2, m2·DH22, and calculates DYV.
The output signal 116 is set to high level when V≧m2·DH22, and set to low level otherwise. Output signal 114 of comparison circuit 35 and output signal 11 of comparison circuit 36
5 and the output signal 116 of the comparison circuit 37 are applied to the determination circuit 38. The output signal 110 of this determination circuit 38 is sent as an output of the image correlation determination circuit 18.

FIG. 3 is a block circuit diagram showing one embodiment of the determination circuit 38 in FIG.
It is composed of an OT circuit 41 and a NOR circuit 42, and the output signal 114 of the comparison circuit 35 is given to one input terminal of the AND circuit 40 and the input terminal of the NOT circuit 41.
The output signal 115 of the comparison circuit 36 and the output signal 116 of the comparison circuit 37 are applied to a NOR circuit 42, and the output of this NOR circuit 42 is applied to the other input terminal of the AND circuit 40 and the output signal 116 of the comparison circuit 37.
The output signal of the NOT circuit 41 is applied to one input terminal of the ND circuit 39 , and the output signal of the NOT circuit 41 is applied to the other input terminal of the AND circuit 39 . The output signal of this AND circuit 39 and the AND
The output signal of the circuit 40 becomes the output signal 110 of the image correlation determination circuit 18.

FIG. 4 is a block circuit diagram showing an embodiment of the horizontal color signal non-correlation energy extraction circuit 27 in FIG. 44, a subtraction circuit 45 and an absolute value circuit 46, the output signal 1 of the first one-line delay circuit 13
02 is given to one input terminal of the delay circuit 44 and the subtraction circuit 45, and the output signal of the delay circuit 44 is supplied to the subtraction circuit 4.
5 to the other input terminal. The output signal of the subtraction circuit 45 is given to an absolute value circuit 46, and the absolute value circuit 4
The output of 6 becomes the horizontal direction color signal non-correlation energy DCH.

FIG. 5 is a block circuit diagram of an embodiment of the horizontal luminance signal decorrelation energy extraction circuit 28 in FIG. a delay circuit 48 having a delay amount of 2fsc));
49, subtraction circuits 50, 51, absolute value circuits 52, 53, and maximum value circuit 54. Output signal 1 of the 1-line delay circuit 14 of 2
03 is applied to a vertical low-pass filter 47, and the output of this vertical low-pass filter 47 is supplied to a delay circuit 4.
8 and one input terminal of the subtraction circuit 50, and the output of the delay circuit 48 is given to the delay circuit 49, the other input terminal of the subtraction circuit 50, and one input terminal of the subtraction circuit 51. The output is given to the other input terminal of the subtraction circuit 51, and the output of the subtraction circuit 50 is given to the absolute value circuit 5.
2, the output of this absolute value circuit 52 is given to the maximum value circuit 54, and the output of the subtraction circuit 51 is given to the absolute value circuit 53.
The output of this absolute value circuit 53 is given to the maximum value circuit 5
given to 4. The output of the maximum value circuit 54 becomes the output DYH of the horizontal luminance signal non-correlation energy extraction circuit 28.

FIG. 6 is a block circuit diagram of an embodiment of the vertical color signal non-correlation energy extraction circuit 29 in FIG.
, an absolute value circuit 58, the output signal 101 of the A/D converter 12 is given to the horizontal band-pass filter 55, and the output signal 103 of the second 1-line delay circuit 14 is given to the horizontal band-pass filter 56. The output of the horizontal band-pass filter 55 is given to one input terminal of the subtraction circuit 57, and the output of the horizontal band-pass filter 56 is
It is applied to the other input terminal of the subtraction circuit 57. The input of this subtraction circuit 57 is given to an absolute value circuit 58, and the output of this absolute value circuit 58 becomes the output DCV of the vertical color signal non-correlation energy extraction circuit 29.

FIG. 7 is a block circuit diagram of an embodiment of the vertical luminance signal decorrelation energy extraction circuit 30 in FIG.
Horizontal low-pass filters 59, 60, 61, subtraction circuits 62, 63, absolute value circuits 64, 65, and maximum value circuit 66
The output signal 101 of the A/D converter 12
is applied to the horizontal low-pass filter 59, and the first one
The output signal 102 of the line delay circuit 13 is given to the horizontal low-pass filter 60, and the second 1-line delay circuit 1
The output signal 103 of No. 4 is given to a horizontal low-pass filter 61. The output of the horizontal low-pass filter 59 is applied to one input terminal of the subtraction circuit 62, and the output of the horizontal low-pass filter 60 is applied to the other input terminal of the subtraction circuit 62 and one input terminal of the subtraction circuit 63. The output of the horizontal low-pass filter 61 is given to the other input terminal of the subtraction circuit 63, the output of the subtraction circuit 62 is given to the absolute value circuit 64, and the output of the subtraction circuit 63 is given to the other input terminal of the subtraction circuit 63.
5, the outputs of the absolute value circuits 64 and 65 are given to a maximum value circuit 66, and the output of this maximum value circuit 66 is the output DYV of the vertical luminance signal decorrelation energy extraction circuit 30.
becomes.

The operation of the embodiment shown in FIGS. 1 to 7 will be explained. When an NTSC composite color television signal is applied through the input terminal 11, the A/D converter 12 samples this composite color television signal at a sampling frequency fs=4fsc. The sampled composite color television signal is transferred to a first one-line delay circuit 13.
and the second one-line delay circuit 14,
A sample value at a certain sample point of interest and two reference sample points one line above and one line below the sample point of interest on the screen are extracted simultaneously. That is, the composite color television signal (sample value) S(m, n) at the position of coordinates (m, n)
appears at the output 102 of the first 1-line delay circuit 13, the signal (m, n-1) appears at the output 103 of the second 1-line delay circuit 14, and the output of the A/D converter 12 A signal S(m, n+1) appears at 101 (see FIG. 17). The signal 102 is passed to the horizontal color signal extraction filter 19, and this signal 102 and the other two signals 101 and 10 are
3 are applied to the inputs of the vertical color signal extraction filter 16, the horizontal/vertical color signal extraction filter 17, and the image correlation determination circuit 18, respectively. For example, the transfer function of the vertical color signal extraction filter 16 at this time is:

[0032]

[Math 3]

The transfer function of the horizontal color signal extraction filter 19 is expressed as Ch (Z)=(1/4)(1-Z-2)2,
Further, the transfer function of the horizontal/vertical color signal extraction filter 17 is as follows:

[0034]

[Math 4]

It is expressed as follows. The output signal 104 of the vertical color signal extraction filter 16 is also used as the output signal 105 of the compensation delay circuit 20 and the horizontal color signal extraction filter 19.
The output signal 106 of the compensation delay circuit 22 is the output signal 10 of the compensation delay circuit 22.
7, and a horizontal/vertical color signal extraction filter 17
The output signal 108 of is the output signal 10 of the compensation delay circuit 21.
9 are respectively applied to the switch circuit 23. The correlation between the images in the vertical and horizontal directions with respect to the sample point of interest is detected, and when the correlation in the horizontal direction is particularly weak, the output signal 105 of the compensation delay circuit 20 to which the output signal 104 of the vertical color signal extraction filter 16 is input is detected. When the vertical correlation is particularly weak, the compensation delay circuit 22 receives the output signal 106 of the horizontal color signal extraction filter 19.
Otherwise, the switch circuit 23 is switched to select the output signal 109 of the compensation delay circuit 21 to which the output signal 108 of the horizontal/vertical color signal extraction filter 17 is input. . Detection of the image correlation and control of the switch circuit 23 are performed by the image correlation determination circuit 18, and the image correlation determination circuit 18 controls the switch circuit by the following operations. The horizontal color signal uncorrelated energy is DCH (Z), the horizontal brightness signal uncorrelated energy is DYH (Z), the vertical color signal uncorrelated energy is DCV (Z), and the vertical brightness signal uncorrelated energy is Let DYV be expressed as follows.

[0036]

[Math 5]

At this time, the first horizontally uncorrelated energy DH1, the second horizontally uncorrelated energy DH21,
The third horizontal non-correlation energy DH22 and vertical non-correlation energy DV are expressed as follows. DH1=C・DYH+d・DCH DH21=max(e1・DYH+f1・DCH)DH
22=max(e2・DYH+f2・DCH)DV=m
In the ax(g・DYV+h・DCV) comparison circuit 35, D
Comparing H1 and n・DV, if DH1≧n・DV, it is determined that the correlation is weak in the horizontal direction, and the judgment circuit 3
The signal 114 of "1" is sent to DH1
When DV, it is determined that the correlation in the horizontal direction is strong, and the determination circuit 3
A signal 114 of "0" is sent to the terminal 8. The comparison circuit 36 compares DCV and m1・DH21 and determines that DCV≧m1・
When DH21, it is determined that the correlation is weak in the vertical direction, and the determination circuit 3
8 and sends a signal 115 of "1" to DCV<m1.
・When DH21, it is judged that the correlation is strong in the vertical direction, and the judgment circuit 3
A signal 115 of "0" is sent to the terminal 8. The comparison circuit 37 compares DYV and m2・DH22 and determines that DYV≧m2・
When DH22, it is determined that the correlation is weak in the vertical direction, and the determination circuit 3
The signal 116 of "1" is sent to the terminal 8, and DYV<m2
・When DH22, it is judged that the correlation is strong in the vertical direction, and the judgment circuit 3
A signal 116 of "0" is sent to the terminal 8. The determination circuit 38 controls the switch circuit 23 as follows according to the above correlation detection result. That is, the input signals 114, 115, 116 to the determination circuit 38, the output signal 110, and the color output signals 105, 10 selected by the switch circuit 23
7,109 is as shown in Table 1.

[0038]

[Table 1]

That is, the switch circuit 23 outputs the output signal 110a of the AND circuit 39 and the output signal 1 of the AND circuit 40.
10b are both "0", the output signal 107 of the compensation delay circuit 22 is selected, and the output signal 11 of the AND circuit 39 is selected.
When 0a is "0" and the output signal 110b of the AND circuit 40 is "1", the output signal 105 of the compensation delay circuit 20 is selected, and when the output signal 110a of the AND circuit 39 is "1", the output of the AND circuit 40 is selected. When the signal 110b is "0", the output signal 109 of the compensation delay circuit 21 is selected. Therefore, in the embodiment shown in FIG. 1, the filter characteristic C(Z) for color signal extraction is as follows depending on the presence or absence of correlation: When vertical correlation is weak, C(Z)=Ch(Z) When horizontal correlation is weak, C (Z)=Cv(Z) When neither is the case, the switching is as follows: C(Z)=Chv(Z).

Example 2. FIG. 9 shows the configuration of an image correlation determination circuit in an embodiment of the invention according to claim 2. First, the horizontal color signal uncorrelated energy extraction circuit 27
d・DC obtained by multiplying the output DCH1 of a by d in the multiplier 72
H1 and C.DYH are input to an adder circuit 31 to detect DH1. The maximum value circuit 8 calculates f1・DCH2 and e1・DYH obtained by multiplying one of the output DCH2 of the second horizontal direction color signal uncorrelated energy extraction circuit 27b by f1 by the multiplier 74a.
2a, DH21 is detected, and the other side of DCH2 is multiplied by f2 by the multiplier 74b, f2・DCH2 and e2・D.
Input YH to the maximum value circuit 82b to detect DH22,
Second vertical color signal non-correlation energy extraction circuit 29b
h・DCV obtained by multiplying the output DCV2 by h in the multiplier 78
2 and g・DYV are input to the maximum value circuit 83 to detect DV, the comparison circuit 35 compares DH1 and n・DV, the comparison circuit 36 compares DCV1 and m1・DH21, and the comparison circuit 37 The configuration is such that DYV and m2/DH22 are compared. Note that the selection control operation of the switch circuit 23 by the output 110 of the determination circuit 38 in the embodiment shown in FIG. 9 is the same as in Table 1. In the above embodiment, the composite color television signal is sampled at a frequency four times as high as the color subcarrier synchronized with the horizontal scanning frequency. For example, sampling is not limited to four times the color subcarrier, but may be performed at other frequencies. Further, the digital filter used in the above embodiment is merely an example, and the filter may have a larger number of orders, for example. Furthermore, in the above embodiment, a luminance signal/chrominance signal separation filter for the NTSC system was described, but the 1-line delay circuits 13 and 14 in FIG. 1 are changed to 2-line delay circuits 13a and 14a as shown in FIG. It's okay. Furthermore, in the above embodiment, each digital filter has F
Although an IR filter has been described, this may also be configured as an IIR filter.

Example 3. FIG. 10 shows the configuration of an image correlation determination circuit according to an embodiment of the invention according to claim 3. This embodiment is the first embodiment shown in FIG.
The output signal 114 of the comparison circuit 35 is sent to the delay circuit 86, the output signal 115 of the comparison circuit 36 is sent to the delay circuit 87, and the output signal 116 of the comparison circuit 37 is sent to the delay circuit 88 and the AND circuit 90.
Then, the output signal 119 of the delay circuit 88 is connected to the delay circuit 89 and A.
The output signal 120 of the delay circuit 89 is connected to the ND circuit 90.
The D circuit 90 receives the output signal 117 of the delay circuit 86, the output signal 118 of the delay circuit 87, and the output signal 1 of the AND circuit 90.
21 is applied to the determination circuit.

Next, the operation of the embodiment shown in FIG. 10 will be explained. The operations up to the comparator circuits 35, 36, and 37 are the same as those in the embodiment shown in FIG. 2, so their explanation will be omitted. The signal 114 is delayed by 1/2 fsc in the delay circuit 86, and the signal 115 is delayed by 1/2 fsc in the delay circuit 87, and each of the signals is input to the determination circuit 38. The signal 116 is 1/2 fsc in the delay circuit 88.
This output signal 119 is further delayed by 1/2 fsc in the delay circuit 89 and sent to the AND circuit 90 as the signal 12.
0 is input, and this AND circuit 90 receives signals 116, 1
19 is also input. The determination circuit 38 includes a delay circuit 86,
87 and the output signals 117, 118, 1 of the AND circuit 90
21 are respectively input.

As explained in the embodiment of FIG. 2, the determination circuit 38 controls the switch circuit 23 according to the correlation detection result. Input signals 117, 118, 12 to determination circuit 38
1, an output signal 110 (see FIG. 3), and a switch circuit 2
Color output signals 105, 107, 10 selected in 3
9 is as shown in Table 2.

[0044]

[Table 2]

That is, the switch circuit 23 outputs the output signal 110a of the AND circuit 39 and the output signal 1 of the AND circuit 40.
10b are both "0", the output signal 107 of the compensation delay circuit 22 is selected, and the output signal 11 of the AND circuit 39 is selected.
When 0a is "0" and the output signal 110b of the AND circuit 40 is "1", the output signal 105 of the compensation delay circuit 20 is selected, and when the output signal 110a of the AND circuit 39 is "1", the output of the AND circuit 40 is selected. When the signal 110b is "0", the output signal 109 of the compensation delay circuit 21 is selected. Therefore, in this embodiment, the color signal extraction filter characteristic C
(Z) depends on the presence or absence of correlation.When the vertical correlation is weak, C(Z)=Ch(Z) When the horizontal correlation is weak, C(Z)=Cv(Z) When there is neither, C(Z) )=Chv(Z).

Example 4. FIG. 11 shows the configuration of an image correlation determination circuit according to an embodiment of the invention according to claim 4. First horizontal color signal decorrelation energy extraction circuit 2
d・D obtained by multiplying the output DCH1 of 7a by d in the multiplier 72
CH1 and C.DYH are input to an adder circuit 31 to detect DH1. The multiplier 74a adds f1 to one of the output DCH2 of the second horizontal color signal non-correlation energy extraction circuit 27b.
DH21 is detected by inputting f1・DCH2 and e1・DYH multiplied by
DYH is input to the maximum value circuit 82b to detect DH22, and the second vertical color signal non-correlation energy extraction circuit 29
h・DCV2 obtained by multiplying the output DCV2 of b by the multiplier 78
and g・DYV are input to the maximum value circuit 83 to detect DV, the comparison circuit 35 compares DH1 and n・DV, the comparison circuit 36 compares DCV1 and m1・DH21, and the comparison circuit 37 detects DYV. The configuration is such that the data and m2/DH22 are compared. Note that the selection control operation of the switch circuit 23 by the output 110 of the determination circuit 38 in the embodiment shown in FIG. 11 is the same as shown in Table 2.

In the above embodiment, the signal 116 is passed through two delay circuits so that the signal 121 becomes "1" when all the sample values of the reference sample points before and after the sample point of interest are "1". However, R reference sample points before and after the sample point of interest (
The number is not limited to two, as long as they are placed in the same number before and after each other so that non-correlation can be detected over R: an integer. In this case, the number of delay circuits through which the signals 114 and 115 pass is also R in accordance with the number R.

Example 5. FIG. 12 shows the configuration of an image correlation determination circuit according to an embodiment of the invention according to claim 5. In the same figure, 73, 74, 75, 76, 77a,
77b, 78a, 78b, 79, 80a, and 80b are multiplication circuits, and the output signal DCH of the horizontal color signal non-correlation energy extraction circuit 27 is divided into two parts, one of which is given to the comparison circuit 36 and the other to the multiplier 74. After being multiplied by f, it is applied to the maximum value circuit 82. The output signal DYH of the horizontal luminance signal non-correlation energy extraction circuit 28 is divided into two parts, one of which is applied to the comparator circuit 37 and the other multiplied by a constant e by the multiplier 73 and then applied to the maximum value circuit 82. The output signal DCV of the vertical color signal non-correlation energy extraction circuit 29 is divided into three parts, one side is multiplied by a constant b by a multiplier 76 and then given to the addition circuit 32, and the other side is multiplied by a constant h1 by a multiplier 78a. The other signal is multiplied by a constant h2 by a multiplier 78b and then provided to the maximum value circuit 83b. The output signal DYV of the vertical luminance signal non-correlation energy extraction circuit 30 is divided into three parts, one is multiplied by a constant a by a multiplier 75 and then given to the addition circuit 32, and the other is multiplied by a constant g1 by a multiplier 77a. The other signal is multiplied by a constant g2 by a multiplier 77b and then provided to the maximum value circuit 83b.

The output signal of the maximum value circuit 82 is multiplied by a constant m by a multiplier 79 as horizontal non-correlation energy DH, and then applied to the comparison circuit 35. The output signal of the adder circuit 32 is given to the comparator circuit 35 as the first vertically uncorrelated energy DV1. The output signal of the maximum value circuit 83a is multiplied by a constant n1 by a multiplier 80a as second vertically uncorrelated energy DV21, and then sent to the comparator circuit 3.
given to 6. The output signal of the maximum value circuit 83b is used as the third vertically uncorrelated energy DV22 and is applied to the multiplier 80b.
After being multiplied by a constant n2, the signal is applied to the comparison circuit 37.

The comparison circuit 35 compares the first vertical non-correlation energy DV1 with the horizontal non-correlation energy DH multiplied by a constant m, and outputs the output signal 114 when DV1≧m・DH. Set to high level, otherwise set to low level. The comparison circuit 36 compares the horizontal color signal uncorrelated energy DCH with the second vertical uncorrelated energy DV21 multiplied by a constant n1, n1・DV21, and sets the output signal 115 to high when DCH≧n1・DV21. level, and low level at all other times. The comparison circuit 37 compares the horizontal brightness signal uncorrelated energy DYH with the third vertical uncorrelated energy DV22 multiplied by a constant n2, n2·DV22, and calculates DYH.
The output signal 116 is set to high level when H≧n2·DV22, and set to low level otherwise. Output signal 114 of comparison circuit 35 and output signal 11 of comparison circuit 36
5 and the output signal 116 of the comparison circuit 37 are applied to the determination circuit 38. The output signal 110 of this determination circuit 38 is sent as an output of the image correlation determination circuit 18.

Next, the image correlation determination circuit 18 of this embodiment
Explain the operation. The horizontal decorrelation energy is DH, the first vertical decorrelation energy is DV1, the second vertical decorrelation energy is DV21, and the third vertical decorrelation energy DV22 is expressed as follows. DH=max(e・DYH,f・DCH)DV1=a・
DYV+b・DCV DV21=max(g1・DYV, h1・DCV) DV
22=max(g2・DYV, h2・DCV) The comparison circuit 35 compares DV1 and m・DH and determines that DV1≧m・
When DH, it is determined that the correlation is weak in the vertical direction, and the determination circuit 3
A signal 114 of "1" is sent to the terminal 8, and DV1<m・
When DV, it is determined that the correlation is strong in the vertical direction, and the determination circuit 3
A signal 114 of "0" is sent to the terminal 8. The comparison circuit 36 compares DCH and n1・DV21 and determines that DCH≧n1・DV21.
When DV21, it is determined that the correlation in the horizontal direction is weak, and a signal 115 of "1" is sent to the determination circuit 38, and if DCH<n
1.DV21, it is determined that the correlation is strong in the horizontal direction, and a signal 115 of "0" is sent to the determination circuit 38. The comparison circuit 37 compares DYH and n2・DV22 and determines that DYH≧n2
- When DV22, it is judged that the correlation in the horizontal direction is weak, and the signal 116 of "1" is sent to the judgment circuit 38, and if DYH<n
2.DV22, it is determined that the correlation is strong in the horizontal direction, and a signal 116 of "0" is sent to the determination circuit 38. The determination circuit 38 controls the switch circuit 23 as follows according to the above correlation detection result. That is, the input signals 114, 115, 116 and the output signal 110 to the determination circuit 38 and the color output signals 105, 10 selected by the switch circuit 23
7,109 is as shown in Table 3.

[0052]

[Table 3]

That is, the switch circuit 23 outputs the output signal 110a of the AND circuit 39 and the output signal 1 of the AND circuit 40.
10b are both "0", the output signal 105 of the compensation delay circuit 20 is selected, and the output signal 11 of the AND circuit 39 is selected.
When 0a is "0" and the output signal 110b of the AND circuit 40 is "1", the output signal 107 of the compensation delay circuit 22 is selected, and when the output signal 110a of the AND circuit 39 is "1", the output of the AND circuit 40 is selected. When the signal 110b is "0", the output signal 109 of the compensation delay circuit 21 is selected. Therefore, in the embodiment shown in FIG. 12, the filter characteristic C(Z) for color signal extraction is as follows depending on the presence or absence of correlation: When the vertical correlation is weak, C(Z)=Ch(Z) When the horizontal correlation is weak, C(Z) )=Cv(Z) When neither is the case, the switching is as follows: C(Z)=Chv(Z).

Example 6. FIG. 13 shows an image correlation determination circuit according to an embodiment of the invention according to claim 6. In this embodiment, the fifth embodiment shown in FIG. 12 is similar to the second embodiment shown in FIG. This is a separate configuration. Furthermore, Figure 13
The selection control operation of the switch circuit 23 by the output 110 of the determination circuit 38 in the embodiment shown in FIG.

Example 7. FIG. 14 shows an image correlation determination circuit according to an embodiment of the invention according to claim 7. The same delay circuits 86 to 89 and an AND circuit 90 as in FIG. 10 are added between the comparison circuits 35 to 37 and the determination circuit 38 in the embodiment in FIG. 12, and these added parts are the same as in the embodiment in FIG. The determination circuit 38 operates according to the input signals 117, 118, 1
21, the switch circuit 23 is controlled according to the correlation detection result described in the embodiment of FIG. Table 4 shows the relationship between the input signals 117, 118, 121 of the determination circuit 38, the output signal 110, and the color output signals 105, 107, 109 selected by the switch circuit 23.

[0056]

[Table 4]

Example 8. FIG. 15 shows an image correlation determination circuit according to an embodiment of the invention according to claim 8. In this embodiment, the seventh embodiment shown in FIG. 14 is similar to the second embodiment shown in FIG. This is a separate configuration. Note that the selection control operation of the switch circuit 23 by the output 110 of the determination circuit 38 in the embodiment shown in FIG. 15 is the same as in Table 4.

[0058]

As described above, according to the present invention, the correlation between the vertical and horizontal images of a composite color television signal is detected, and based on the detection result, a luminance signal and chrominance signal separation filter with different characteristics is applied. Since the configuration is configured to select and output the output signals of the luminance signal and chrominance signal, it is possible to reduce the influence of leakage of the luminance signal and chrominance signal into each channel, thereby providing a luminance signal and chrominance signal separation filter that can reduce dot interference. effective.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of an embodiment of an NTSC luminance signal/chrominance signal separation filter according to the invention;

FIG. 2 is a block circuit diagram showing one embodiment of the image correlation determination circuit in FIG. 1;

FIG. 3 is a circuit diagram showing one embodiment of the determination circuit in FIG. 2;

FIG. 4 is a block circuit diagram showing an embodiment of the horizontal color signal non-correlation energy extraction circuit in FIG. 2;

FIG. 5 is a block circuit diagram showing an embodiment of the horizontal direction luminance signal non-correlation energy extraction circuit in FIG. 2;

FIG. 6 is a block circuit diagram showing an embodiment of the vertical color signal decorrelation energy extraction circuit of FIG. 2;

FIG. 7 is a block circuit diagram showing an embodiment of the vertical luminance signal non-correlation energy extraction circuit in FIG. 2;

FIG. 8 is a block circuit diagram of an embodiment of a PAL luminance signal chrominance signal separation filter according to claim 1;

FIG. 9 is a block circuit diagram of an embodiment of an image correlation determination circuit according to a second aspect of the invention;

FIG. 10 is a block circuit diagram of an embodiment of an image correlation determination circuit according to a third aspect of the invention;

FIG. 11 is a block circuit diagram of an embodiment of an image correlation determination circuit according to a fourth aspect of the invention.

FIG. 12 is a block circuit diagram of an embodiment of an image correlation determination circuit according to a fifth aspect of the invention.

FIG. 13 is a block circuit diagram of an embodiment of an image correlation determination circuit according to a sixth aspect of the invention.

FIG. 14 is a block circuit diagram of an embodiment of an image correlation determination circuit according to a seventh aspect of the invention.

FIG. 15 is a block circuit diagram of an embodiment of an image correlation determination circuit according to an eighth aspect of the invention.

FIG. 16 is a block circuit diagram of a conventional luminance signal chrominance signal separation filter.

FIG. 17 is an explanatory diagram showing an arrangement on a screen of a signal sequence obtained by synchronously sampling an NTSC system composite color television signal at four times the color subcarrier;

[Explanation of symbols]

12 A/D converters 13, 14 1-line delay circuits 13a, 14a 2-line delay circuit 16 Vertical color signal extraction filter 17 Horizontal/vertical color signal extraction filter 18 Image correlation determination circuit 19 Horizontal color signal extraction filter 23 Switch Circuit 25 Subtractors 27, 27a, 27b Horizontal color signal non-correlation energy extraction circuit 28 Horizontal luminance signal non-correlation energy extraction circuit 29
, 29a, 29b Vertical color signal non-correlation energy extraction circuit 30 Vertical luminance signal non-correlation energy extraction circuit 31
Addition circuits 35-37 Comparison circuit 38 Judgment circuits 71-80, 73a, 73b, 74a, 74b, 77a
, 77b, 78a, 78b, 79a, 79b, 80a,
80b Multipliers 82, 82a, 82b, 83, 83a, 83b Maximum value circuits 86 to 89 Delay circuit 90 AND circuit

Claims (8)

[Claims] Claim 1: A composite video signal sampled at a frequency synchronized with the horizontal scanning frequency is delayed one line at a time or two lines at a time to simultaneously obtain each sample value of a sample point of interest and a plurality of reference sample points around it. a horizontal color signal extraction filter for extracting a frequency component corresponding to a horizontal color subcarrier component from the sample value of the sample point of interest to obtain a first color signal; a vertical color signal extraction filter for obtaining a second color signal by extracting a frequency component corresponding to a vertical color subcarrier component from each sample value of the reference sample point; and each sample of the sample point and the reference sample point. A horizontal/vertical color signal extraction filter for extracting frequency components corresponding to vertical and horizontal color subcarrier components from the values to obtain a third color signal, and selecting the first to third color signals. a switch circuit for outputting a color signal as a color signal; a subtracter that subtracts the color signal selected by the switch circuit from the sample value of the sample point and outputs a luminance signal, and the image correlation determination means extracts the horizontal direction from the first delayed composite color television signal. A horizontal color signal uncorrelated energy extraction circuit that mainly extracts uncorrelated energy of color signals, and a horizontal luminance signal that extracts mainly uncorrelated energy of horizontal luminance signals from the above three types of composite color television signals. an uncorrelated energy extraction circuit; a vertical color signal uncorrelated energy extraction circuit that extracts uncorrelated energy mainly of color signals in the vertical direction from the composite color television signal and the second delayed composite color television signal; A vertical luminance signal uncorrelated energy extraction circuit extracts mainly luminance signal uncorrelated energy in the vertical direction from a composite color television signal of various types, and a value obtained by multiplying the horizontal chrominance signal uncorrelated energy by a predetermined coefficient and a horizontal an addition circuit that adds and outputs a value obtained by multiplying the direction brightness signal uncorrelated energy by a predetermined coefficient;
a first maximum value circuit that compares a value obtained by multiplying horizontal color signal uncorrelated energy by a predetermined coefficient and a value obtained by multiplying horizontal direction brightness signal uncorrelated energy by a predetermined coefficient, and outputs a larger value; , a second maximum value circuit that compares the value obtained by multiplying the horizontal color signal uncorrelated energy by a predetermined coefficient and the value obtained by multiplying the horizontal direction brightness signal uncorrelated energy by a predetermined coefficient, and outputs the larger value; and a third maximum value that compares the value obtained by multiplying the vertical color signal uncorrelated energy by a predetermined coefficient and the value obtained by multiplying the vertical direction brightness signal uncorrelated energy by a predetermined coefficient, and outputs the larger value. The circuit is compared with the output value of the adder circuit and the third maximum value circuit multiplied by a predetermined coefficient, and if the former is large, the horizontal correlation is weak, and if the latter is large, the horizontal correlation is weak. is the output value of the first comparison circuit that outputs a signal indicating that the horizontal correlation is strong, the output value of the vertical color signal non-correlation energy extraction circuit, and the output value of the first maximum value circuit, multiplied by a predetermined coefficient. a second comparison circuit that outputs a signal indicating that the vertical correlation is weak when the former is large and that the vertical correlation is weak when the latter is large; The output value of the vertical luminance signal uncorrelated energy extraction circuit is compared with the output value of the second maximum value circuit multiplied by a predetermined coefficient, and if the former is large, it is determined that the vertical correlation is weak. of,
If the latter is large, a third comparator circuit outputs a signal indicating that the vertical correlation is strong, and the output signals of the three comparator circuits are taken in, and each of the horizontal correlation and vertical correlation is calculated. The strength is determined, and if the vertical correlation is weak, the first color signal is used, if the horizontal correlation is weak, the second color signal is used, and if both the horizontal and vertical correlations are A luminance signal/chrominance signal separation filter comprising: a determination circuit that outputs the third color signal from a switch circuit if the third color signal is strong. 2. The image correlation determination means according to claim 1, wherein the image correlation determination means extracts the first horizontal color signal decorrelation energy mainly in the horizontal direction from the first delayed composite color television signal. an extraction circuit; a second horizontal color signal uncorrelated energy extraction circuit for extracting mainly color signal uncorrelated energy in the horizontal direction from the three types of composite color television signals; a horizontal luminance signal uncorrelated energy extraction circuit for extracting horizontally primarily luminance signal uncorrelated energy from the signal; a vertically primarily chrominance signal from the composite color television signal and a second delayed composite color television signal; a first vertical color signal uncorrelated energy extraction circuit for extracting the uncorrelated energy of the color signals; and a second vertical color signal extracting circuit for extracting the uncorrelated energy of the vertical color signals from the three types of composite color televisions. a signal uncorrelated energy extraction circuit; a vertical luminance signal uncorrelated energy extraction circuit for extracting uncorrelated energy mainly of vertical luminance signals from the three types of composite color televisions;
a second horizontal color signal; a first maximum value circuit that compares a value obtained by multiplying the uncorrelated energy by a predetermined coefficient and a value obtained by multiplying the horizontal direction luminance signal uncorrelated energy by a predetermined coefficient, and outputs a larger value; a second maximum value circuit that compares a value obtained by multiplying horizontal color signal uncorrelated energy by a predetermined coefficient and a value obtained by multiplying horizontal direction brightness signal uncorrelated energy by a predetermined coefficient, and outputs a larger value; , a third maximum value circuit that compares a value obtained by multiplying the vertical color signal uncorrelated energy by a predetermined coefficient and a value obtained by multiplying the vertical direction brightness signal uncorrelated energy by a predetermined coefficient, and outputs a larger value; and the value obtained by multiplying the output value of the adder circuit and the third maximum value circuit by a predetermined coefficient, and if the former is large, the correlation in the horizontal direction is weak, and if the latter is large, the horizontal correlation is weak. A predetermined coefficient is applied to the output value of the first comparison circuit that outputs a signal indicating that the correlation in the horizontal direction is strong, the output value of the first vertical color signal non-correlation energy extraction circuit, and the output value of the first maximum value circuit. A second comparison circuit outputs a signal indicating that the vertical correlation is weak when the former is large, and that the vertical correlation is strong when the latter is large. Then, the output value of the vertical luminance signal non-correlation energy extraction circuit is compared with the value obtained by multiplying the output value of the second maximum value circuit by a predetermined coefficient, and if the former is large, the vertical correlation is A third comparison circuit outputs a signal indicating that the correlation in the vertical direction is weak, and if the latter is large, the correlation in the vertical direction is strong. The strength of each correlation is determined, and if the vertical correlation is weak, the first color signal is used, and if the horizontal correlation is weak, the second color signal is used, and the horizontal and vertical correlations are If the correlation is strong, the third color signal is
A luminance signal/chrominance signal separation filter comprising a determination circuit that outputs each from a switch circuit. 3. According to claim 1, the image correlation determining means comprises a horizontal color signal uncorrelated energy extraction circuit for extracting mainly color signal uncorrelated energy in the horizontal direction from the first delayed composite color television signal. , a horizontal direction luminance signal decorrelation energy extraction circuit for extracting the decorrelation energy mainly of the luminance signal in the horizontal direction from the above three types of composite color television signals, and a composite color television signal and a second delayed composite color television signal. A vertical color signal uncorrelated energy extraction circuit that extracts uncorrelated energy mainly of color signals in the vertical direction from the signal, and a vertical color signal uncorrelated energy extraction circuit that extracts uncorrelated energy mainly of luminance signals in the vertical direction from the above three types of composite color television signals. a vertical luminance signal uncorrelated energy extraction circuit that adds and outputs a value obtained by multiplying the horizontal direction color signal uncorrelated energy by a predetermined coefficient and a value obtained by multiplying the horizontal direction luminance signal uncorrelated energy by a predetermined coefficient. A first circuit that compares a value obtained by multiplying the horizontal direction color signal non-correlation energy by a predetermined coefficient with a value obtained by multiplying the horizontal direction luminance signal non-correlation energy by a predetermined coefficient, and outputs the larger value.
A maximum value circuit compares the value obtained by multiplying the horizontal color signal uncorrelated energy by a predetermined coefficient and the value obtained by multiplying the horizontal direction brightness signal uncorrelated energy by a predetermined coefficient, and outputs the larger value. 2 maximum value circuit compares the value obtained by multiplying the vertical color signal uncorrelated energy by a predetermined coefficient and the value obtained by multiplying the vertical direction brightness signal uncorrelated energy by a predetermined coefficient, and outputs the larger value. a third maximum value circuit, an adding circuit and a third maximum value circuit;
The output value of the maximum value circuit is compared with the value obtained by multiplying the output value by a predetermined coefficient, and if the former is large, the horizontal correlation is weak, and if the latter is large, the horizontal correlation is strong. The output value of the first comparison circuit that outputs the signal, the output value of the vertical color signal non-correlation energy extraction circuit, and the value obtained by multiplying the output value of the first maximum value circuit by a predetermined coefficient are compared, and the former A second comparison circuit outputs a signal indicating that the vertical correlation is weak when the latter is large, and a signal indicating that the vertical correlation is strong when the latter is large, and a vertical luminance signal uncorrelated energy extraction circuit. The output value of the circuit is compared with the value obtained by multiplying the output value of the second maximum value circuit by a predetermined coefficient, and if the former is large, the correlation in the vertical direction is strong, and if the latter is large, indicates that there is a strong vertical correlation.
A third comparison circuit that outputs a signal, a first delay circuit that delays the output signal of the first comparison circuit by 1/2 period (1/2 fsc) of the color subcarrier, and a second comparison circuit that outputs a signal. a second delay circuit that delays the output signal by 1/(2fsc);
a third delay circuit that delays the output signal of the third comparator circuit by 1/(2fsc);
/(2fsc), the output signal of the third comparison circuit, the output signal of the third delay circuit, and the fourth delay circuit.
an AND circuit that inputs the output signal of the delay circuit, and an AND circuit that inputs the output signal of the first delay circuit, the output signal of the second delay circuit, and
The output signal of the D circuit is taken in, and the strength of the horizontal correlation and vertical correlation is determined. If the vertical correlation is weak, the first color signal is used, and if the horizontal correlation is weak, the first color signal is used. and a determination circuit that outputs the second color signal from the switch circuit, and outputs the third color signal when both the horizontal and vertical correlations are strong, from the switch circuit. Signal color signal separation filter. 4. The image correlation determination means according to claim 1, wherein the image correlation determination means extracts the first horizontal color signal decorrelation energy mainly in the horizontal direction from the first delayed composite color television signal. an extraction circuit; a second horizontal color signal uncorrelated energy extraction circuit for extracting mainly color signal uncorrelated energy in the horizontal direction from the three types of composite color television signals; a horizontal luminance signal uncorrelated energy extraction circuit for extracting horizontally primarily luminance signal uncorrelated energy from the signal; a vertically primarily chrominance signal from the composite color television signal and a second delayed composite color television signal; a first vertical color signal uncorrelated energy extraction circuit for extracting the uncorrelated energy of the color signals; and a second vertical color signal extracting circuit for extracting the uncorrelated energy of the vertical color signals from the three types of composite color televisions. a signal uncorrelated energy extraction circuit; a vertical luminance signal uncorrelated energy extraction circuit for extracting uncorrelated energy mainly of vertical luminance signals from the three types of composite color televisions;
a second horizontal color signal; a first maximum value circuit that compares a value obtained by multiplying the uncorrelated energy by a predetermined coefficient and a value obtained by multiplying the horizontal direction luminance signal uncorrelated energy by a predetermined coefficient, and outputs a larger value; a second maximum value circuit that compares a value obtained by multiplying horizontal color signal uncorrelated energy by a predetermined coefficient and a value obtained by multiplying horizontal direction brightness signal uncorrelated energy by a predetermined coefficient, and outputs a larger value; , a third maximum value circuit that compares a value obtained by multiplying the vertical direction color signal uncorrelated energy by a predetermined coefficient with a value obtained by multiplying the vertical direction brightness signal uncorrelated energy by a predetermined coefficient, and outputs a larger value; , compare the output value of the adder circuit and the third maximum value circuit multiplied by a predetermined coefficient,
A first comparison circuit outputs a signal indicating that the horizontal correlation is weak when the former is large, and a signal indicating that the horizontal correlation is strong when the latter is large, and a first vertical color signal. The output value of the uncorrelated energy extraction circuit is compared with the value obtained by multiplying the output value of the first maximum value circuit by a predetermined coefficient, and if the former is large, the correlation in the vertical direction is weak, and the latter is A second comparison circuit outputs a signal indicating that the correlation in the vertical direction is strong when the correlation is large, the output value of the vertical direction luminance signal uncorrelation energy extraction circuit, and the output value of the second maximum value circuit are predetermined. , and outputs a signal indicating that the vertical correlation is weak if the former is large, and that the vertical correlation is strong if the latter is large. a comparison circuit, a first delay circuit that delays the output signal of the first comparison circuit by 1/(2fsc), and a second delay circuit that delays the output signal of the second comparison circuit by 1/(2fsc). and a third delay circuit that delays the output signal of the third comparison circuit by 1/(2fsc);
a fourth delay circuit that delays the output signal of the third delay circuit by 1/(2fsc); an output signal of the third comparison circuit; an output signal of the third delay circuit; and an output signal of the fourth delay circuit. The AND circuit that inputs the input signal, the output signal of the first delay circuit, the output signal of the second delay circuit, and the output signal of the AND circuit are taken in, and the strength of the horizontal correlation and vertical correlation is determined. , when the correlation in the vertical direction is weak, the first color signal is used, and when the correlation in the horizontal direction is weak, the second color signal is used.
and a determination circuit that outputs the third color signal from a switch circuit when both the horizontal and vertical correlations of the color signals are strong, respectively. . 5. According to claim 1, the image correlation determining means comprises a horizontal color signal uncorrelated energy extraction circuit for extracting mainly color signal uncorrelated energy in the horizontal direction from the first delayed composite color television signal. , a horizontal direction luminance signal decorrelation energy extraction circuit for extracting the decorrelation energy mainly of the luminance signal in the horizontal direction from the above three types of composite color television signals, and a composite color television signal and a second delayed composite color television signal. A vertical color signal uncorrelated energy extraction circuit extracts uncorrelated energy mainly of color signals in the vertical direction from the 3 types of composite color television signals, and extracts uncorrelated energy mainly of luminance signals in the vertical direction from the above three types of composite color television signals. The vertical luminance signal uncorrelated energy extraction circuit compares the value obtained by multiplying the horizontal direction chrominance signal uncorrelated energy by a predetermined coefficient and the value obtained by multiplying the horizontal direction luminance signal uncorrelated energy by a predetermined coefficient, and extracts the larger value. The first maximum value circuit that outputs the value compares the value obtained by multiplying the vertical direction color signal uncorrelated energy by a predetermined coefficient and the value obtained by multiplying the vertical direction luminance signal uncorrelated energy by a predetermined coefficient, A second maximum value circuit that outputs the value of A third maximum value circuit outputs a large value, and adds the value obtained by multiplying the vertical color signal uncorrelated energy by a predetermined coefficient and the value obtained by multiplying the vertical direction luminance signal uncorrelated energy by a predetermined coefficient. An output adder circuit, this adder circuit and the first
The output value of the maximum value circuit is compared with the value obtained by multiplying the output value by a predetermined coefficient, and if the former is large, the vertical correlation is weak, and if the latter is large, the vertical correlation is strong. The first comparison circuit that outputs the signal, the output value of the horizontal color signal non-correlation energy extraction circuit, and the value obtained by multiplying the output value of the second maximum value circuit by a predetermined coefficient are compared, and the former A second comparison circuit outputs a signal indicating that the horizontal correlation is weak when the latter is large, and a signal indicating that the horizontal correlation is strong when the latter is large, and horizontal luminance signal uncorrelated energy extraction. The output value of the circuit is compared with the value obtained by multiplying the output value of the third maximum value circuit by a predetermined coefficient, and if the former is large, the horizontal correlation is weak, and if the latter is large, the horizontal correlation is weak. takes in the output signals of the three comparison circuits and the third comparison circuit that outputs a signal indicating that the horizontal correlation is strong, determines the strength of the horizontal correlation and the vertical correlation, and calculates the vertical correlation. When the correlation in the direction is weak, the first color signal is used, when the correlation in the horizontal direction is weak, the second color signal is used, and when the correlation in both the horizontal and vertical directions is strong, the third color signal is used. A luminance signal/color signal separation filter comprising: a determination circuit for outputting each of the color signals from a switch circuit. 6. The image correlation determination means according to claim 1, wherein the image correlation determination means extracts first horizontal color signal decorrelation energy mainly in the horizontal direction from the first delayed composite color television signal. an extraction circuit; a second horizontal color signal uncorrelated energy extraction circuit for extracting mainly color signal uncorrelated energy in the horizontal direction from the three types of composite color television signals; a horizontal luminance signal uncorrelated energy extraction circuit for extracting horizontally primarily luminance signal uncorrelated energy from the signal; a vertically primarily chrominance signal from the composite color television signal and a second delayed composite color television signal; a first vertical color signal uncorrelated energy extraction circuit for extracting the uncorrelated energy of the color signals; and a second vertical color signal extracting circuit for extracting the uncorrelated energy of the vertical color signals from the three types of composite color televisions. a signal decorrelation energy extraction circuit; a vertical luminance signal decorrelation energy extraction circuit for extracting decorrelation energy mainly of luminance signals in the vertical direction from the three types of composite color televisions;
a first maximum value circuit that compares a value obtained by multiplying horizontal color signal non-correlation energy by a predetermined coefficient and a value obtained by multiplying horizontal direction brightness signal non-correlation energy by a predetermined coefficient, and outputs a larger value; and a second unit that compares a value obtained by multiplying the second vertical direction color signal uncorrelated energy by a predetermined coefficient and a value obtained by multiplying the vertical direction luminance signal uncorrelated energy by a predetermined coefficient, and outputs the larger value. The maximum value circuit compares the value obtained by multiplying the second vertical color signal uncorrelated energy by a predetermined coefficient and the value obtained by multiplying the vertical direction brightness signal uncorrelated energy by a predetermined coefficient, and selects the larger value. A third maximum value circuit that outputs, adds and outputs a value obtained by multiplying the first vertical color signal non-correlation energy by a predetermined coefficient and a value obtained by multiplying the vertical direction luminance signal non-correlation energy by a predetermined coefficient. The output value of the adder circuit and the output value of the adder circuit and the first maximum value circuit multiplied by a predetermined coefficient are compared, and if the former is large, the correlation in the vertical direction is weak; In this case, the output value of the first comparator circuit that outputs a signal indicating that the correlation in the vertical direction is strong, the output value of the first horizontal color signal decorrelation energy extraction circuit, and the output value of the second maximum value circuit. A second signal that outputs a signal indicating that the horizontal correlation is weak when the former is large, and that the horizontal correlation is strong when the latter is large, is compared with the value multiplied by a predetermined coefficient. The comparison circuit compares the output value of the horizontal direction luminance signal non-correlation energy extraction circuit with the value obtained by multiplying the output value of the third maximum value circuit by a predetermined coefficient, and if the former is large, the horizontal direction A third comparator circuit outputs a signal indicating that the correlation in the horizontal direction is weak, and a signal indicating that the correlation in the horizontal direction is strong when the latter is large. The strength of each direction correlation is determined, and if the vertical correlation is weak, the first color signal is used, and if the horizontal correlation is weak, the second color signal is used, and the horizontal and vertical correlations are determined. A luminance signal/chrominance signal separation filter comprising: a determination circuit that outputs the third color signal from each switch circuit when the correlation in both directions is strong. 7. According to claim 1, the image correlation determining means comprises a horizontal color signal uncorrelated energy extraction circuit for extracting mainly color signal uncorrelated energy in the horizontal direction from the first delayed composite color television signal. , a horizontal direction luminance signal decorrelation energy extraction circuit for extracting the decorrelation energy mainly of the luminance signal in the horizontal direction from the above three types of composite color television signals, and a composite color television signal and a second delayed composite color television signal. A vertical color signal uncorrelated energy extraction circuit extracts uncorrelated energy mainly of color signals in the vertical direction from the 3 types of composite color television signals, and extracts uncorrelated energy mainly of luminance signals in the vertical direction from the above three types of composite color television signals. The vertical luminance signal uncorrelated energy extraction circuit compares the value obtained by multiplying the horizontal direction chrominance signal uncorrelated energy by a predetermined coefficient and the value obtained by multiplying the horizontal direction luminance signal uncorrelated energy by a predetermined coefficient, and extracts the larger value. A first maximum value circuit that outputs a value compares the value obtained by multiplying the vertical color signal uncorrelated energy by a predetermined coefficient and the value obtained by multiplying the vertical direction luminance signal energy by a predetermined coefficient, and outputs the larger value. A second maximum value circuit that outputs A third maximum value circuit that outputs a value, adds and outputs a value obtained by multiplying the vertical direction color signal uncorrelated energy by a predetermined coefficient and a value obtained by multiplying the vertical direction luminance signal uncorrelated energy by a predetermined coefficient. The adder circuit compares the output value of the adder circuit and the first maximum value circuit multiplied by a predetermined coefficient, and if the former is large, the vertical correlation is weak; if the latter is large, it is determined that the vertical correlation is weak. The first output signal indicates that there is a strong correlation in the vertical direction.
The comparison circuit compares the output value of the horizontal color signal non-correlation energy extraction circuit with the value obtained by multiplying the output value of the second maximum value circuit by a predetermined coefficient, and if the former is large, the horizontal direction A second comparator circuit outputs a signal indicating that the correlation is weak, and if the latter is large, a signal indicating that the horizontal correlation is strong. The output value of the maximum value circuit is compared with the value obtained by multiplying the output value by a predetermined coefficient, and if the former is large, the horizontal correlation is weak, and if the latter is large, the horizontal correlation is strong. a first delay circuit that delays the output signal of the first comparison circuit by 1/2 period (1/(2fsc)) of the color subcarrier; The output signal of the comparison circuit is 1/
a second delay circuit that delays the output signal of the third comparison circuit by 1/(2fsc); and a third delay circuit that delays the output signal of the third comparison circuit by 1/(2fsc).
The output signals of the delay circuit and the third delay circuit are divided by 1/(2f
a fourth delay circuit that delays by sc), an AND circuit that inputs the output signal of the third comparison circuit, the output signal of the third delay circuit, and the output signal of the fourth delay circuit, and the first delay circuit. The output signal of the second delay circuit, the output signal of the second delay circuit, and the output signal of the AND circuit are taken in, and the strengths of the horizontal correlation and the vertical correlation are determined, and if the vertical correlation is weak, the above-mentioned If the correlation in the horizontal direction is weak, the second color signal is output, and if the correlation in both the horizontal and vertical directions is strong, the third color signal is output from the switch circuit. A luminance signal/chrominance signal separation filter comprising: a determination circuit for determining a luminance signal and a color signal. 8. The image correlation determination means according to claim 1, wherein the image correlation determination means extracts the first horizontal color signal decorrelation energy mainly in the horizontal direction from the first delayed composite color television signal. an extraction circuit; a second horizontal color signal uncorrelated energy extraction circuit for extracting mainly color signal uncorrelated energy in the horizontal direction from the three types of composite color television signals; a horizontal luminance signal uncorrelated energy extraction circuit for extracting horizontally primarily luminance signal uncorrelated energy from the signal; a vertically primarily chrominance signal from the composite color television signal and a second delayed composite color television signal; a first vertical color signal uncorrelated energy extraction circuit for extracting the uncorrelated energy of the color signals; and a second vertical color signal extracting circuit for extracting the uncorrelated energy of the vertical color signals from the three types of composite color televisions. a signal decorrelation energy extraction circuit; a vertical luminance signal decorrelation energy extraction circuit for extracting decorrelation energy mainly of luminance signals in the vertical direction from the three types of composite color television;
a first maximum value circuit that compares a value obtained by multiplying horizontal color signal non-correlation energy by a predetermined coefficient and a value obtained by multiplying horizontal direction brightness signal non-correlation energy by a predetermined coefficient, and outputs a larger value; and a second maximum value that compares the value obtained by multiplying the second vertical color signal uncorrelated energy by a predetermined coefficient and the value obtained by multiplying the vertical direction luminance signal energy by a predetermined coefficient, and outputs the larger value. The value circuit compares the value obtained by multiplying the second vertical color signal uncorrelated energy by a predetermined coefficient and the value obtained by multiplying the vertical luminance signal uncorrelated energy by a predetermined coefficient, and outputs the larger value. A third maximum value circuit, and an addition that adds and outputs a value obtained by multiplying the first vertical color signal non-correlation energy by a predetermined coefficient and a value obtained by multiplying the vertical direction luminance signal non-correlation energy by a predetermined coefficient. The circuit is compared with the output value of the adder circuit and the first maximum value circuit multiplied by a predetermined coefficient, and if the former is large, the vertical correlation is weak; if the latter is large, the correlation is weak. is the output value of the first comparison circuit that outputs a signal indicating that the vertical correlation is strong, the output value of the first horizontal color signal non-correlation energy extraction circuit, and the output value of the second maximum value circuit. A second comparison that outputs a signal indicating that the horizontal correlation is weak when the former is large, and that the horizontal correlation is strong when the latter is large. The output value of the horizontal luminance signal uncorrelated energy extraction circuit is compared with the output value of the third maximum value circuit multiplied by a predetermined coefficient, and if the former is large, the horizontal correlation is determined. A third comparator circuit outputs a signal indicating that the horizontal correlation is weak, and a signal indicating that the horizontal correlation is strong if the latter is large, and the output signal of the first comparator circuit is 1/(2fsc
)), a second delay circuit that delays the output signal of the second comparison circuit by 1/(2fsc), and a third delay circuit that delays the output signal of the third comparison circuit by 1/(2fsc). a third delay circuit that delays the output signal of the third delay circuit by 1/(2fsc);
an AND circuit inputting the output signal of the third comparison circuit, the output signal of the third delay circuit, and the output signal of the fourth delay circuit;
The output signal of the first delay circuit, the output signal of the second delay circuit, and the output signal of the AND circuit are taken in, and the strength of the horizontal correlation and the vertical correlation is determined, and the vertical correlation is weak. If the correlation in the horizontal direction is weak, the second color signal is used. If the correlation in both the horizontal and vertical directions is strong, the third color signal is used. A luminance signal/chrominance signal separation filter comprising a determination circuit that outputs each from a switch circuit.