JPH03268595A - Movement adaptive type brightness signal/chrominance signal separating filter - Google Patents

Abstract

PURPOSE:To attain YC separation reducing the deterioration of picture quality such as cross color and dot disturbance even in the case of a moving picture by executing inter-frame YC separation when inter-frame YC separation is large or executing intra-field YC separation only when there is no inter-frame correlation at the time of detecting the moving picture by a movement detection circuit. CONSTITUTION:An intra-frame YC separation circuit part in a conventional filter is replaced by an intra-frame YC separation circuit 50. When the movement detection circuit 80 detects a moving picture, a correlation detecting circuit in the circuit 50 locally detects inter-frame correction or intra-field correlation and outputs the correlation detecting result, and at the time of judging that the detecting result of remarked sampling point is an isolated point based on the detection result of a remarked sampling point of the correlation detection circuit and the detection result of a nearby sampling point in the field, an isolated point removing circuit 60 replaces the correlation detecting result of the remarked sampling point by the correlation detecting result of the nearby sampling point, inter-field processing or intra-field processing is executed based on the result of the circuit 60, and in intra-frame brightness signal/chrominance signal separating brightness signal and an intra-frame brightness signal/ chrominance signal separating chrominance signal is outputted.

Description

Detailed Description of the Invention [Field of Industrial Application] This invention provides a method for converting a luminance signal (hereinafter referred to as rV flaw signal) from a composite color television signal (hereinafter referred to as rV flaw signal) in which a color signal is frequency multiplexed into a high frequency region of a luminance signal. , "Y signal" or simply "Y") and a chrominance signal (hereinafter referred to as "C signal" or simply "C").

[Conventional technology]

The motion adaptive YC separation filter is a filter that locally determines whether an image is a still image or a moving image, and performs YC separation suitable for the pixel signals of each part.

In the current NTSC signaling system, a composite signal is obtained by frequency multiplexing the C signal into the high frequency region of the Y signal. For this reason, YC separation is required in the receiver, and incomplete separation causes image quality deterioration such as cross color and dot crawl.

Therefore, with the development of large-capacity digital memories in recent years, motion adaptation using delay circuits (hereinafter referred to as ``delay circuits'' in Hayabusa) that have a delay time equal to but longer than the vertical scanning frequency of television signals has been developed. Various signal processing circuits have been proposed for improving image quality such as YC separation.

FIG. 10 is a block circuit diagram showing an example of a conventional motion adaptive YC separation filter. In FIG. 10, an NTSC V signal (101) is input to the input terminal (1), an intra-field YC separation circuit (4), an inter-frame YC separation circuit (5), a Y-signal motion detection circuit (6) and The C signal is applied to the input terminal of the motion detection circuit (7).

In the intra-field YC separation circuit (4), the intra-field YC separated Y (g (102)) and the intra-field YC separated C signal (103), which are YC-separated by an intra-field filter (not shown), are Y( The first input terminal of the g mixing circuit (9) and the C signal mixing circuit (lO)
The first input end of the input terminal is manually inputted.

Furthermore, in the interframe YC separation circuit (5), an interframe YC separated Y signal (104) and an interframe YC separated C signal (105) which are YC separated by an interframe filter (not shown) are Y signals. Mixed circuit (9)
and the second input terminal of the C signal mixing circuit (10).

On the other hand, the Y signal motion amount (106) detected by the Y signal motion detection circuit (6) is input to one input terminal of the synthesis circuit (8), and is also input to the C signal motion detection circuit (7). The signal (107) indicating the detected C signal motion amount is sent to the synthesis circuit (
8) is manually input to the other input terminal.

Motion detection signal (108) synthesized by the synthesis circuit (8)
are respectively input to the third input terminal of the Y signal mixing circuit (9) and the third input terminal of the C signal mixing circuit (10),
Y signal motion detection circuit (8), C signal motion detection circuit (
7) and the synthesis circuit (8) constitute a motion detection circuit (80).

Motion adaptive YC component l1 which is the output of the Y signal mixing circuit (9)
The ilY signal (109) is sent out from the output terminal (2).

In addition, the motion adaptive Y which is the output of the C signal mixing circuit (10)
The C minute@C signal (110) is sent out from the output terminal (3).

Next, the operation of this conventional example will be explained. The motion detection circuit (80) synthesizes the outputs of the Y signal motion detection circuit (6) and the C signal motion detection circuit (7) in the synthesis circuit (8) in order to separate the ■signal (101) into Y and C signals. signal(
101) is a signal representing a still image or a signal representing movement.

For example, as shown in FIG. 11, the Y signal motion detection circuit (6) inputs the vf= signal (101) from the input terminal (51) and receives a signal delayed by one frame by the one frame delay circuit (53). , and directly manually input ■signal (101) using a subtractor (54) to obtain a one-frame difference of ■signal (101), which is then passed through a low-pass filter (hereinafter referred to as rLPFJ) (55). After that, the absolute value is determined by the absolute value circuit (56), and this absolute value is converted to the nonlinear conversion circuit (57).
A signal indicating the amount of movement of the low frequency component of the Y signal (10B)
and output it to the output terminal (52).

The C signal motion detection circuit (7) also receives a V signal (101) which is manually inputted from the input terminal (11) as shown in FIG.
) is delayed by 2 frames by the 2-frame delay circuit (41), and the directly input signal (101) is subtracted by the subtracter (42) to obtain the 2-frame difference. After passing through a pass filter (hereinafter referred to as rBPFJ) (43), its absolute value is determined by an absolute value circuit (44), and this absolute value is converted into a signal (107) indicating the amount of movement of the C signal by a nonlinear conversion circuit (45). ) and output from output 1f49).

The synthesis circuit (8) is configured to select and output the larger value of, for example, the Y signal motion amount (106) and the C signal motion amount (107).

This discrimination result is expressed in the form of a motion coefficient k (0≦≦1); for example, if the image is determined to be a completely still image, k=o, or if the image is determined to be a completely moving image. In this case, the Y signal mixing circuit (9
) and the control signal (108) to the C signal mixing circuit (10).
given as.

Generally, when the image is a still image, interframe YC separation using interframe correlation is performed to separate the Y signal and C
Separate the signals.

The inter-frame YC separation circuit (5) receives, for example, the ■ signal (101) input from the input terminal (61) as shown in FIG.
) is delayed by one frame in a one-frame delay circuit (64) and the directly input V signal (101) are added in an adder (65) to obtain a one-frame sum and the YF flaw signal 104) The CF flaw signal is extracted and output to the output @ (62), and the YF flaw signal 104) is subtracted from the V signal (101) input from the input terminal (61) using the subtracter (66). 105) and output terminal (63
) is outputting from.

Further, in general, when the image is a moving image, intra-field YC separation using intra-field correlation is performed to separate the Y signal and the C signal. In-field YC separation circuit (4)
For example, as shown in Fig. 14, the V signal (101) manually inputted from the input terminal (71) is delayed by one line in the one line delay circuit (74), and the V signal (101) manually inputted directly
1) are added in the adder (75) to obtain the one-line sum and extract the Yf multiplied signal 102), which is output from the output terminal (72), and is output from the subtracter (76) at the input terminal (71). Yf multiplied signal 102) from the V signal (101) input from
By reducing the Cf signal (103),
It is output from the output end (73).

The motion adaptive YC separation filter uses such an intra-field YC separation circuit (4) and an inter-frame YC separation circuit (5).
), and using the motion coefficient k synthesized by the synthesis circuit (8), the Y signal mixing circuit (9) performs the following calculation and outputs a motion adaptive YC component lIY signal (109). Output from end (2).

Y=to-Yf+ (1-k)YF Here, Yf: Intra-field YC minute 111Y signal output (102) YF: Interframe YC minute my signal output (104).

Similarly, the control signal (108) controls the C signal mixing circuit (
10) performs the following calculations and outputs a motion adaptive YC separated C signal (110) from the output end (3).

C=to-Cf+ (1-k)CF where, Cf: Intra-field YC minute IIC signal output (103) CF: Interframe YC minute IIC signal output (105).

Of this motion adaptive YC separation filter, the C signal motion detection circuit (7) can also be realized with a configuration as shown in FIG.

In this FIG. 15, the ■ signal (1
01) is manually input and demodulated into two types of color difference signals RY and BY by a color demodulation circuit (46).

These two types of color difference signals R-Y and B-Y are time-division multiplexed at a certain frequency in a time-division multiplexing circuit (47), delayed by two frames in a two-frame delay circuit (41), and then delayed by a subtraction circuit ( 42), the output of the two-frame delay circuit (41) and the output of the time-division multiplexing circuit (47) are subtracted to obtain a two-frame difference.

The two-frame difference is passed through L P F (48)
The signal component is removed, the absolute value is taken by the absolute value circuit (44), and the nonlinear conversion circuit (45) performs nonlinear conversion to obtain C.
The motion detection amount (107) of the signal is sent out from the output terminal (49).

[Problem to be solved by the invention]

Since the conventional motion-adaptive YC separation filter is configured as described above, the motion detection circuit (6) and the C-signal motion detection circuit (7) calculate the , In-field YC separation circuit (
4) Yf signal and Cf signal, and interframe YC
The YF flaw signal and the CF flaw signal are mixed by the dividing circuit (5).

Therefore, because the filter characteristics for still images and those for moving images are completely different, there is an extreme change in resolution when moving from a still image to a moving image, or from a moving image to a still image. There was a problem in that the image quality was noticeably degraded.

This invention was made in order to solve the above-mentioned problems, and it is a motion-adaptive type that can reproduce images with high resolution and little image quality deterioration even if the above-mentioned processing is changed frequently. The purpose is to obtain a luminance signal chrominance signal separation filter.

[Means for Solving the Problems] A motion adaptive luminance signal/chrominance signal separation filter according to the present invention locally detects correlation between frames or within a field when a motion detection circuit detects a moving image, and detects the correlation between frames or within a field. The present invention is characterized in that an intra-frame YC separation circuit is provided which performs inter-field processing based on the detection result and outputs an intra-frame YC signal and an intra-frame YC signal.

[Effect]

The intra-frame YC separation circuit in this invention performs YC separation between fields even if the motion detection circuit determines that it is a moving image, if the correlation between fields is large, and performs YC separation within the field only when there is no correlation between fields. After performing separation, the intra-frame YC separated Y signal and the intra-frame YC'7 separated C
Output a signal.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a motion adaptive luminance signal/chrominance signal separation filter of the present invention will be described below with reference to the drawings. FIG. 1 is a block circuit diagram of this embodiment. In this figure, the in-field YC separation circuit (4) in the conventional example shown in FIG. 10 is replaced with the intra-frame YC separation circuit (50). Since the configurations are the same, a description of the configuration and operation of the same parts will be omitted.

FIG. 2 shows a block circuit diagram of the intra-frame YC separation circuit (50).

In FIG. 2, the ■signal (101) input from the input terminal (11) is sent to the 262-line delay circuit (15),
The signal is input to a 1-line delay circuit (14) and a 2-pixel delay circuit (22). The output of the 262 line delay circuit (15) is 1
The line delay circuit (17) and the two-pixel delay circuit (16) are manually operated. The output of the 1-line delay circuit (17) is input to a 2-pixel delay circuit (18) and a 262-line delay circuit (19). The output of the two-pixel delay circuit (18) is a one-line delay circuit (23), adders (26), (27).

(28), (29) are input to the subtracter (40).

The output of the one-line delay circuit (23) is input to an adder (26) and a subtracter (30). 262 line delay circuit (1
The output of 9) is inputted to a 1-line delay circuit (20), a 4-pixel delay circuit (24), an adder (27), and a subtracter (31). The output of the 4-pixel delay circuit (24) is an adder (28)
, are manually input to the subtractor (32). 1 line delay circuit (2
0) is input to a 2-pixel delay circuit (25), and the output of the 2-pixel delay circuit (25) is input to an adder (29) and a subtracter (
33). The output of the two-pixel delay circuit (16) is input to a subtracter (30). 1 line delay circuit (14
) is input to the 4-pixel delay circuit (21) and the subtracter (32), and the output of the 4-pixel delay circuit (21) is input to the subtracter (3).
1) is input. The output of the two-pixel delay circuit (22) is input to a subtracter (33). Subtractor (30), (3
The outputs of 1), (32), and (33) are absolute value circuits (34), (35), (3δ), and (3δ), respectively.
7) Human power, absolute value circuit (34), (35)
, (36), (37) are outputted by the minimum value selection circuit (
39). Adder (26), (27)
, (28).

The output of (29) is input to the signal selection circuit (38).

The output (116) of the minimum value selection circuit (39) is input to the isolated point removal circuit (60), and the output of the isolated point removal circuit (60) is input to the signal selection circuit (38) as a selection signal. The output of the signal selection circuit (38) is input to a subtracter (40) and outputted from an output terminal (12) as an intra-frame YC/IY signal (112). The output of the subtracter (40) is output from the output terminal (13) as an intra-frame YC signal @C signal (113).

A block circuit diagram of the isolated point removal circuit (60) in FIG. 2 is shown in FIG. In FIG. 3, a correlation signal (116) is input manually to the input terminal (91). This correlation signal (11
B) is a 1-pixel delay circuit (3e) and a 1-line delay circuit (9).
c). The output of the 1-line delay circuit (9C) is input to a 1-line delay circuit (9d), a comparison circuit (llb), a 2-pixel delay circuit (3h), and a 1-pixel delay circuit (3g). The output of the 1-line delay circuit (9d) is input to the 1-pixel delay circuit (3f). 1 pixel delay circuit (3e).

The output of (3f) is inputted to a comparator circuit (lla).

The output of the 2-pixel delay circuit (3h) is input to the comparison circuit (llb). Comparison circuit (lla), (llb) 1
The output of the pixel delay circuit (3g) is inputted to the selection circuit (12a), and the output of the selection circuit (12a) is inputted to the control signal (118).
) is output from the output terminal (92).

Next, the operation will be explained. If we take the horizontal direction of the screen as the X axis, the vertical direction of the screen as the y axis, and the time axis as the t axis in the direction perpendicular to the plane composed of the X and y axes, then the You can think of a three-dimensional space-time that can be constructed.

Figure 5 is a diagram representing three-dimensional space-time, and Figure 5(a)
is a plane composed of the t-axis and the y-axis, Fig. 5(b), (
c) is a plane composed of the X axis and the y axis.

FIG. 5(a) also shows interlaced scanning lines,
The broken line n1 indicates one field, and the solid line indicates that the color subcarriers are in phase.

In addition, the solid line in FIG. 5(b) indicates the scanning line of the n field, and the broken line indicates the scanning line of the n-1 field.
The solid line in c) indicates the scanning line of n field, and the - dotted line indicates n+
1 field is shown.

In addition, the four types of marks r□, r・, △, and mu on the scanning line indicate the color subcarrier frequency fsC (=3.5
8MH2) represents sample points whose color subcarriers have different phases when digitized, and the same marks represent sample points with the same phase.

Now, if we represent the sample point of interest as "◎", there are four sample points a, b, c, sample points c and d two sample points before and after the n field, which is the same field as the sample points a and b one line above and below. The color subcarrier phases differ by 180 degrees at d.

Therefore, a line comb filter using a digital circuit or an adaptive Y
A C separation filter etc. can be configured.

Furthermore, as shown in FIG. 5(a), since the color subcarrier phases differ by 180 degrees at the same sample point one frame apart, an interframe YC separation filter can also be configured.

Furthermore, as can be seen from Fig. 5(b), in the n-1 field one field before the sample point of interest, the phase is opposite at sample point A on one line or two sample points before and after A on one line below. Therefore, inter-field YC separation is possible using any one of these three points A, B, and B and the point of interest.

Furthermore, considering the μ-axis which is a horizontal frequency axis, the y-axis which is a vertical frequency axis, and the f-axis which is a time frequency as frequency axes corresponding to the above-mentioned X-axis, y-axis, and t-axis, the μ-axis is orthogonal to each other, It is possible to consider a three-dimensional frequency space that can be composed of a cy-axis and an f-axis.

FIG. 6 shows a projection diagram of the above three-dimensional frequency space,
FIG. 6(a) is a diagram of the three-dimensional frequency space viewed from an oblique direction, FIG. 6(b) is a diagram of the three-dimensional frequency space viewed from the negative direction of the f-axis, and FIG. 6(c) is a diagram of the three-dimensional frequency space viewed from an oblique direction. is a diagram of the above three-dimensional frequency space viewed from the positive direction of the μ axis.

The spectral distribution of the V signal on the three-dimensional frequency space is also shown in FIGS. 6(a) to 6(c). Figure 6 (
As can be seen from a) to Fig. 6(c), the spectrum of the Y signal spreads around the origin of the three-dimensional frequency space, and
The spectrum of the C signal is as shown in Fig. 6(a) because the I signal and C signal are orthogonally modulated at the color subcarrier frequency fSC.
- They are located in four spaces as shown in Figure 6(C).

However, when the V signal is viewed on the μ axis as shown in FIG. 6(C), the C signal exists only in the second and fourth quadrants.

This corresponds to the fact that the solid line representing the same phase of the color subcarriers in FIG. 5(b) becomes thinner over time.

Nevertheless, in the conventional example, when motion in an image is detected, YC separation is performed using correlation within the field, so band limitation in the μ-axis and cy-axis directions is possible, but band limitation in the f-axis direction is It was not possible to add directional band limits.

Therefore, the frequency space in which the child signal originally exists is separated as the C signal, and the band of the Y signal in the moving image becomes narrow.

Therefore, by performing YC separation using inter-field processing as described above, it is possible to widen the band of the Y signal in a moving image.

In FIG. 5(b), there are two sample points A, B, which are located in the vicinity of the sample point of interest in the n-1 field and whose color subcarrier phases differ by 180°.

By calculating with any of these three points, ``Y between fields
C separation becomes possible.

First, consider YC separation by calculation between the sample point of interest and sample point A in FIG. 5(b).

The Y signal is obtained by the sum of these two sample points, and the C signal is obtained by the difference.

Figures 7(a) to 7(C) are shown in Figures 6(a) to 6(C).
Similarly to c), it represents a three-dimensional frequency space, and shows the frequency space in which the Y signal and C signal obtained by the calculation between the sample point of interest and sample point A exist.

Second, considering YC separation by calculation between the sample point of interest and sample point A in Figure 5(b), the Y signal is obtained by the sum of these two sample points, and the C signal is obtained by the difference. .

Similarly, FIGS. 8(a) to 8(C) also show the frequency space where the Y signal and C signal exist, which are obtained by calculation between the sample point of interest and the sample point A. Figures 8(a) to 8(c)
It appears that some C signals are included in the separated Y signal, but since the Y signal and C signal have a strong correlation,
It is extremely rare for a signal to include a C signal.

Thirdly, considering YC separation by calculation of the sample point of interest and one sample point in FIG. 5(b), a Y signal is obtained by the sum of these two sample points, and a C signal is obtained by the difference.

Similarly, FIGS. 9(a) to 9(c) also show the frequency space in which the Y signal and C signal exist, which are obtained by calculation between the sample point of interest and the sample point.

Looking at FIGS. 9(a) to 9(C), it seems that the separated Y signal includes a part of the C signal, but in FIG. 8(a)
For the same reason as shown in FIG. 8(c), it is extremely rare for the Y signal to include the C signal.

In order to adaptively switch and control these three types of inter-field YC separation, it is necessary to detect the correlation between the sample point of interest and sample points A, B, and I.

In Figure 5(b), the correlation between the sample point of interest and the sample point A of the n-1 field is detected by the absolute value of the difference between the sample point of the n+1 field and the sample point A in Figure 5(C). .

Similarly, the correlation between the sample point of interest and the sample point A of the n-1 field is detected by the absolute value of the difference between the sample point O and the sample point I of the n+1 field in FIG. 5(C).

Further, the correlation between the sample point of interest and one sample point of field n-1 is detected by the absolute value of the difference between the sample point power of field n+1 and one sample point in FIG. 5(C).

When performing intra-field processing, correlations are detected within the field. At this time, the correlation between the sample point of interest and sample point a in FIG. 5(b) is detected by the absolute value of the difference between sample point a and sample point S. By comparing these absolute difference values, we can detect the direction with the strongest correlation and also remove isolated points within the field. The correlation directions of adjacent sample points a, b, c, and d are compared, and if it is determined that the correlation result of the sample point of interest is an isolated point, the correlation result of the sample point of interest is corrected.

Next, the intra-frame YC separation circuit (50
) operation will be explained. In the embodiment shown in FIG. 1, when the motion detection circuit (80) determines that the image is a moving image, the optimum one of three types of inter-field YC separation or intra-field YC separation is used for moving image processing. It is a feature.

In FIG. 2, a V signal (101) input from an input terminal (11) is processed by a 262-line delay circuit (15), a 1-line delay circuit (17), and a 2-pixel delay circuit (18). Line and two pixels delayed.

Furthermore, the signal delayed by one line by the one-line delay circuit (23) is added by the adder (26), and the result is shown in FIG. 5(b).
By performing calculations between the sample point of interest and the sample point a, an intra-field YC+Y signal is output.

In addition, the output of the 1-line delay circuit (17) is delayed by 262 lines in the 262-line delay circuit (19), and is added to the output of the 2-pixel delay circuit (18) in the adder (27), as shown in FIG. 5(b). By performing calculations on the sample point of interest and the sample point, inter-field YC portion wiY signals are output.

In addition, the output of the 262-line delay circuit (19) is further 4
The pixel delay circuit (24) delays 4 pixels, and the output of the 4-pixel delay circuit (24) is added to the output of the 2-pixel delay circuit (18) in the adder (28). By performing calculations on the sample point and sample point A, an inter-field YC separated Y signal is output.

Further, the output of the 262-line delay circuit (engine 9) is delayed by 1 line and 2 pixels by a 1-line delay circuit (20) and a 2-pixel delay circuit (25). The output of the 2-pixel delay circuit (25) is combined with the output of the 2-pixel delay circuit (18) and the adder (29).
By performing calculations on the sample point of interest and sample point A in FIG. 5(b), an inter-field YC separated Y signal is output.

Also, the V signal (101) input to the human power J (11)
is a 262-line delay circuit (15) and a 2-pixel delay circuit (
16) is delayed by 262 lines and 2 pixels, and the output of the 2-pixel delay circuit (16) is subtracted from the output of the 1-line delay circuit (23) by a subtracter (30), and the sample point in FIG. 5(b) is Then, the difference of sample point a is taken. The output of the subtracter (30) is converted into an absolute value by an absolute value circuit (34), and then input to a minimum value selection circuit (39).

Further, the V signal (101) input to the input terminal (11) is delayed by 1 line in the 1-line delay circuit (14), delayed by 4 pixels in the 4-pixel delay circuit (21), and delayed by 4 pixels in the 4-pixel delay circuit (21). ) is subtracted from the output of the 262-line delay circuit (19) by a subtracter (31), and the difference between the sample point power in FIG. 5(C) and the sample point power in FIG. 5(b) is taken. The output of the subtracter (31) is the absolute value circuit (35)
The absolute value is converted into an absolute value and input to the minimum value selection circuit (39).

In addition, the output of the 1-line delay circuit (14) is subtracted from the output of the 4-pixel delay circuit (24) by a subtracter (32), and the sample point O in FIG. 5(C) and the sample point O in FIG. The difference from point A is taken. The output of the subtracter (32) is converted into an absolute value by an absolute value circuit (36), and the output is converted to an absolute value by a minimum value selection circuit (39).
is man-powered.

In addition, the ■signal (101) that was human-powered by human-powered 1 (11)
is delayed by 2 pixels in the 2-pixel delay circuit (22), and the output of the 2-pixel delay circuit (22) is subtracted from the output of the 2-pixel delay circuit (25) in the subtracter (33). ) and the sample point A in Figure 5(b) are taken. The output of the subtracter (33) is sent to the absolute value circuit (3
In step 7), the absolute value is converted into an absolute value and manually inputted to the minimum value selection circuit (39).

The minimum value selection circuit (39) compares the four input absolute difference values 1a-bl, 1a-bl, 1a-bl, 1a-b1, and 1a-b1, and detects the direction with the strongest correlation (in which the absolute difference value is the minimum), Furthermore, the isolated point removing circuit (60) corrects the correlation direction detected as an isolated point.

The signal selection circuit (38) selects the filter in the direction with the highest correlation based on the correlation determination result after removing isolated points, and outputs an intra-frame YC component l1lY signal (112) from the output end (12). do. The subtracter (40) extracts the intra-frame YC separated Y signal (11) from the output of the two-pixel delay circuit (18).
2) and outputs an intra-frame YC component lIC signal (113) from the output end (13).

Next, in FIG. 3, which shows the operation of the isolated point removal circuit (60), the correlation direction detection signal (116) input from the input terminal (91) is delayed by one pixel in the one pixel delay circuit (3e), Also, a 1-line delay circuit (9c).

(9d) and the one pixel delay circuit (3f) delay two lines and one pixel. The outputs of the 1-pixel delay circuits (3e) and (3f) are used in a comparison circuit (lla) to compare the correlation direction detection signal of sample point A and the correlation direction detection signal of sample point A in FIG. 5(b). be exposed. The comparison circuit (lla) calculates that if the direction of correlation between sample point S and the direction of correlation between sample point a are the same, then the direction of correlation between sample points of interest is the same as the direction of correlation between sample points a and b. The correlation direction detection result of the sample point of interest is corrected to be the same as the correlation direction of sample points a and b.

In addition, the correlation direction detection signal of the sample point f in FIG. 5(b) delayed by one line by the one-line delay circuit (9C),
The correlation direction detection signal of the sample point e in FIG. 5(b), which has been delayed by 1 line and 2 pixels by the 1-line delay circuit (9C) and the 2-pixel delay circuit (3h), is compared by the comparator circuit (llb). be exposed. The comparison circuit (llb) determines that if the direction of correlation between sample point f and the direction of correlation between sample point e is the same, then the direction of correlation between sample points of interest is the same as the direction of correlation between sample points e and f. The correlation direction detection result of the sample point of interest is determined as the sample point c.
, d to be the same as the correlation direction. 1 line delay circuit (
9C) and a one-pixel delay circuit (3g) perform a delay for delay compensation, which is manually input to the selection circuit (12a). If no correction is made in the comparison circuits (lla) and (llb), the selection circuit (12a) is controlled so that the correlation direction detection result of the sample point of interest is output as is, and the comparison circuit (, 11a) , (llb), one of the modifications is controlled to have priority and is output from the output terminal (92).

FIG. 4 is a block circuit diagram of another embodiment of the isolated point removal circuit (60), in which the correlation signal (
116) is input to a 1-frame delay circuit (9d), a 1-line delay circuit (7e), and a 2-pixel delay circuit (5j). The output of the one frame delay circuit (9d) is sent to the comparison circuit (ll
a) Manual input to 4 pixel delay circuit (6h) and 1 line delay circuit (7f). The output of the 1-line delay circuit (7e) is input to a 4-pixel delay circuit (6g) and a comparison circuit (llb). The outputs of the 4-pixel delay circuits (6g) and (6h) are input to comparison circuits (11a) and (xtb), respectively. The output of the 1-line delay circuit (7f) is input to the 2-pixel delay circuit (51), and the output is further input to the 2-pixel delay circuit (51).
The output of 1) is input to a comparison circuit (llc). The output of the 2-pixel delay circuit (5j) is sent to the comparison circuit (llc) 2
It is input to a 63-line delay circuit (8d). Comparison circuit (
The output of the 263-line delay circuit (8d) is input to the selection circuit (12a), and the selection circuit (12a) outputs the control signal (118) from the output terminal (92). .

Next, the operation of this isolated point removal circuit (60) will be described. In FIG. 4, the correlation direction detection signal (116) is input from the input terminal (91), and the one frame delay circuit (9d
) and the correlation direction detection signal of one sample point in Fig. 5(b) and the one-line delay circuit (7e
) and the correlation direction detection signal of the sample point force in FIG. 5(C) delayed by 1 line and 4 pixels by the 4-pixel delay circuit (6g) is input to the comparison circuit (lla). Comparison circuit (11
In a), if the correlation direction of the sample point and the force of the sample point are the same, it is determined that the correlation direction of the sample point of interest is the same as the direction of correlation of the force of the sample point, and The correlation direction detection result is corrected to be the same as the force correlation direction at the sample point.

In addition, a 1-frame delay circuit (9d) and a 4-pixel delay circuit (
Figure 5(b) delayed by 1 frame and 4 pixels in 6h)
The correlation direction detection signal of sample point A in FIG. 5(c) and the correlation direction detection signal of sample point O in FIG.
) is entered. If the correlation direction of sample point A and the correlation direction of sample point O are the same, the comparison circuit (llb) determines that the correlation direction of the sample point of interest is the same as the correlation direction of sample points A and A, The correlation direction detection result of the sample point of interest is corrected to be the same as the correlation direction of sample points A and E.

In addition, the correlation direction of sample point A in Fig. 5(b) is delayed by 1 frame, 1 line, and 2 pixels by the 1 frame delay circuit (9d), 1 line delay circuit (7f), and 2 pixel delay circuit (5j). The detection signal and the correlation direction detection signal of the sample point in FIG. 5(C) delayed by 2 pixels by the 2-pixel delay circuit (5j) are input to the comparison circuit (llc). If the correlation direction of sample point A and the correlation direction of sample point D are the same, the comparison circuit (11C) determines that the correlation direction of the sample point of interest is the same as the correlation direction of sample points A and D, Correct the correlation direction detection result of the sample point of interest to be the same as the correlation direction of sample points A and D.

2 pixel delay circuit (5j) and 263 line delay circuit (8d)
) performs a delay for delay compensation, and the selection circuit (12a)
is man-powered. Comparison circuit (lla), (llb)
.

If no correction is made in (llc), the selection circuit (12a) controls the correlation direction detection result of the sample point of interest to be output as is, and the comparison circuit (lla)
, (llb), and (llc), one of the modifications is controlled to have priority and is output from the output terminal (92).

(Effects of the Invention) As described above, according to the present invention, when a motion detection circuit detects a moving image, the intra-frame YC separation circuit locally detects correlation between frames or within a field, and detects correlation between frames. If the correlation is large, YC between fields
Since the configuration is configured to perform YC separation within a field only when there is no correlation between frames, optimal YC separation can be performed using image correlation in video processing with a motion adaptive YC separation filter. Therefore, it is possible to configure a motion-adaptive YC separation filter that performs YC separation with less image quality deterioration such as cross-color dot interference even in moving images.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing a motion adaptive YC separation filter according to an embodiment of the present invention, FIG. 2 is a block circuit diagram showing a detailed configuration of an intra-frame YC separation circuit in this embodiment, and FIGS. FIG. 4 is a block circuit diagram showing different configuration examples of the isolated point removal circuit in this embodiment, and FIG. 5 is a diagram showing an arrangement of V signals digitized by four times the color subcarrier in a three-dimensional time space. FIG. 6 is a diagram showing the spectral distribution of the V signal in a three-dimensional frequency space, and FIG. 7 is a diagram showing the spectral distribution of the Y signal and C signal obtained by the first interfield YC separation according to this embodiment in the three-dimensional frequency space. The figure shown in Figure 8 is the second diagram according to this embodiment.
Figure 9 (
a) is a three-dimensional frequency space diagram of the spectral distribution of the Y signal and C signal obtained by the third interfield YC separation according to this embodiment, and FIG. 10 is a block diagram of a conventional motion adaptive YC separation filter. Circuit diagram: FIG. 11 is a block circuit diagram showing the detailed configuration of the Y signal motion detection circuit used in the motion adaptive YC separation filter of FIG. 10, and FIG. FIG. 13 is a block circuit diagram showing the detailed configuration of the C signal motion detection circuit, FIG. 13 is a block circuit diagram showing the detailed configuration of the interframe YC separation circuit in the motion adaptive YC+ separation filter of FIG. FIG. 10 is a block circuit diagram showing a detailed configuration of the intra-field YC separation circuit in the motion adaptive YC separation filter, and FIG. 15 is a block circuit diagram showing another example of the conventional C signal motion detection circuit. (5)...YC between frames + separation circuit, (6)...Y
Signal motion detection circuit, (7)...C signal motion detection circuit,
(8)...Synthesizing circuit, (9)...Y signal mixing circuit,
(10)...C signal mixing circuit, (50)...Intraframe YC separation circuit, (60)...Intraframe YC separation circuit, (80)...Motion detection circuit. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) In a circuit that separates the luminance signal and chrominance signal from a composite color television signal in which the chrominance signal is frequency-multiplexed into the high frequency region of the luminance signal, local image movement is detected using the correlation between frames. A motion detection circuit that detects a still image, and when this motion detection circuit detects a still image, separates the interframe luminance signal and color signal using interframe correlation to generate the interframe luminance signal, color signal, and separate luminance signal and interframe luminance signal. Color signal separation An interframe luminance signal/color signal separation circuit that outputs a color signal and the motion detection circuit locally detect correlation between frames or within a field when a moving image is detected, and output the correlation detection result. If it is determined that the detection result of the sample point of interest is an isolated point from the correlation detection circuit and the detection result of the sample point of interest by this correlation detection circuit and the detection results of neighboring sample points in the field, the correlation of the sample point of interest is determined. It has an isolated point removal circuit that replaces the detection result with the correlation detection result of neighboring sample points, and performs inter-field processing or intra-field processing based on the result of this isolated point removal circuit to separate intra-frame luminance signals, chrominance signals, and separated luminance signals. An intra-frame luminance signal chrominance signal separation circuit that outputs an intra-frame luminance signal chrominance signal separation color signal, and an inter-frame luminance signal chrominance signal separation luminance signal and an intra-frame luminance signal chrominance signal separation luminance signal based on the output of the motion detection circuit. a luminance signal mixing circuit that mixes the signals and outputs a motion-adaptive luminance signal, chrominance signal, and separated luminance signal; and a luminance signal and chrominance signal between the frames, and the intra-frame luminance signal and chrominance signal, based on the output of the motion detection circuit. A motion-adaptive luminance signal/chrominance signal separation filter comprising a color signal mixing circuit that mixes color signals and outputs a motion-adaptive luminance signal, chrominance signal, and separated color signal. (2) In claim 1, the isolated point removal circuit of the intra-frame luminance signal chrominance signal separation circuit calculates the sample point of interest from the detection result of the sample point of interest of the correlation detection circuit and the detection result of neighboring sample points of the adjacent field. A motion-adaptive luminance signal/chrominance signal separation filter characterized in that it is configured to determine whether a detection result of is an isolated point.