JPH03283794A - Movement adaptive type luminance signal chrominance signal separtion filter - Google Patents

Abstract

PURPOSE:To decrease the deterioration in the resolution of even a moving picture by detecting correlation between frames locally, applying inter-field calculation and applying YC separation in a frame including an in-field band limit of a color signal. CONSTITUTION:An in-frame YC separation circuit 50 is provided, which detects correlation between frames locally when a moving detection circuit 80 detects a moving picture, selects adaptively the interfield calculation and plural in-frame processings including in-field band limit of a color signal, and outputs an in- frame YC separate Y signal and an in-frame YC separate C signal. That is, the in-frame YC separation circuit 50 detects correlation between frames when the movement detection circuit 80 discriminates a moving picture and selects any of 3 kinds of the in-frame YC separation circuits 50 depending on the quantity of the correlation to output the in-frame YC separate Y signal and the in-frame YC separate C signal. Thus, a picture with high resolution and less picture quality deterioration is reproduced even from the picture requiring lots of processing changeover.

Description

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

[Prior Art] A 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 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 recent development of large-capacity digital memories, motion-adaptive YC separation using delay circuits (hereinafter simply referred to as delay circuits) having a delay time equal to or longer than the vertical scanning frequency of television signals has been developed. Various signal processing circuits have been proposed for improving image quality.

FIG. 1O is a block circuit diagram showing an example of a conventional motion adaptive YC separation filter. In this FIG. 1O, an NTSC system V signal 101 is input to the input terminal l,
Intra-field YC separation circuit 4, inter-frame YC separation circuit 5, Y signal motion detection circuit 6, and C signal motion detection circuit 7
are given to the input terminals of respectively.

In the field YC separation circuit 4, the field YC separated by the field filter (not shown)
C-separated Y signal 102 and intra-field YC separated C signal 1
03 are input to the first input terminal of the Y signal mixing circuit 9 and the first input terminal of the C signal mixing circuit 10, respectively.

In the interframe YC separation circuit 5, the interframe YC is separated by an interframe filter (not shown).
C-separated Y signal 104 and interframe YC-separated C signal 10
5 are input to the second input terminal of the Y signal mixing circuit 9 and the second input terminal of the C signal mixing circuit 10, respectively.

On the other hand, the Y signal motion amount 106 detected by the Y signal motion detection circuit 6 is input to the - input terminal of the synthesis circuit 8,
Further, a signal 107 indicating the amount of C signal motion detected by the C signal motion detection circuit 7 is input to the other input terminal of the synthesis circuit 8 .

The motion detection signal 108 synthesized by the synthesis circuit 8 is 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, respectively, and the Y signal motion detection circuit 6 and the C signal The motion detection circuit 7 and the synthesis circuit 8 constitute a motion detection circuit 80.

A motion adaptive YCC separation multiplied signal 09, which is an output of the Y signal mixing circuit 9, is sent out from the output terminal 2.

Further, a motion-adaptive YC-separated C signal 110, which is an output of the C signal mixing circuit IO, is sent out from the output terminal 3.

Next, the operation of this conventional example will be explained.

When the motion detection circuit 80 separates the signal 101 into Y and C, the motion detection circuit 80 includes the Y signal motion detection circuit 6 and the C signal motion detection circuit 7.
A synthesis circuit 8 synthesizes the outputs of 1 and 2 to determine whether the signal 101 is a signal representing a still image or a signal representing movement.

The Y signal motion detection circuit 6, for example, as shown in FIG.
A signal obtained by inputting the V signal 101 from the input terminal 51 and delaying it by one frame by the l-frame delay circuit 53 and the directly inputted V signal 101 are subtracted by the subtracter 54 to obtain the ■signal 10.
1, and apply a low-pass filter (hereinafter referred to as
After passing through 55 (referred to as LPF), its absolute value is determined by an absolute value circuit 56, and this absolute value is converted to Y by a nonlinear conversion circuit 57.
It is converted into a signal 106 indicating the amount of motion of the low frequency component of the signal and outputted to the output terminal 52.

Further, the C signal motion detection circuit 7 receives a signal obtained by delaying the V signal 101 inputted from the input terminal 11 by two frames in a two frame delay circuit 81 as shown in FIG. 12, and a directly inputted V signal. 101 is subtracted by a subtracter 82 to obtain a two-frame difference, which is passed through a band pass filter (hereinafter referred to as BPF) 83, its absolute value is determined by an absolute value circuit 84, and this absolute value is converted to a nonlinear A conversion circuit 85 converts the C signal into a signal 107 indicating the amount of movement, and outputs it from an output terminal 89.

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

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 = 0, and if the image is determined to be a completely moving image, k = 0. is given as a control signal 108 such that k=1.

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 adds a signal obtained by delaying the ■ signal 101 inputted from the input terminal 61 by one frame by one frame delay circuit 64 and the directly inputted V signal 101, as shown in FIG. 13, for example. The YF signal 104 is extracted by calculating the sum of 1 frames, and the output terminal 62
At the same time, by subtracting the YF signal 104 from the V signal 101 input from the input terminal 61 in the subtracter 66, the Cf signal 105 is extracted and output from the output terminal 63.

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. The in-field YC separation circuit 4 is
For example, as shown in FIG. 14, the adder 75 adds the signal obtained by delaying the V signal lot input from the input terminal 71 by one line in the one-line delay circuit 74 and the directly input V signal 101, and adds the l-line sum. , and extract the Yf signal 102.
The Cf signal 103 is output from the output end 72 and is output from the output end 73 by subtracting the Yf signal 102 from the V signal 101 input from the input end 71 in the subtracter 76 .

In the motion adaptive YC separation filter, such an intra-field YC separation circuit 4 and an inter-frame YC separation circuit 5 are arranged side by side, and the motion coefficient k synthesized by the synthesis circuit 8 is used to
The signal mixing circuit 9 is caused to perform the following calculations, and a motion adaptive YCC separation multiplied signal 09 is outputted from the output terminal 2.

Y=kYf+ (1-k)YF where, Yf: In-field YC separated Y signal output 102, YF:
Interframe YC separated Y signal output 104.

Similarly, the control signal 108 causes the C signal mixing circuit IO to perform the following calculations, and outputs the motion adaptive YC separated C signal 110 from the output terminal 3.

C=kCf+ (1-k)CF where, Cf: In-field yc separated C signal output 103, CF・
Interframe YC separated C 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 the figure, a V signal 101 is input from an input terminal 11, and a color demodulation circuit 86 generates two types of color difference signals R-Y and B.
−Y is demodulated.

These two types of color difference signals R-Y and B-Y are time-division multiplexed at a certain frequency by a time-division multiplexing circuit 87, and the two-frame delay circuit 81 combines the output of the two-frame delay circuit 81 with the time-division multiplexing circuit. By performing subtraction with the output of 87, a two-frame difference is obtained.

The two-frame difference is passed through an LPF 88 to remove the Y signal component, an absolute value circuit 84 removes the absolute value, and a nonlinear conversion circuit 85 performs nonlinear conversion to obtain the motion detection amount of the C signal.
07 can be sent out from the output end 89.

[Problems to be Solved by the Invention] Since the conventional motion adaptive YC separation filter is configured as follows, the amount of motion detected by the Y signal motion detection circuit 6 and the C signal motion detection circuit 7 is combined. Based on the YC amount, the YC separation circuit 4 determines the
The f-times signal Cf signal and the YF-times signal CF signal from the inter-frame YC separation circuit 5 are mixed.

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 when the above-mentioned processing is changed frequently. The purpose is to obtain a YC separation filter.

[Means for solving the problem] The motion adaptive YC separation filter according to the present invention has (1)
When the motion detection circuit detects a video, it locally detects the correlation between frames, and uses the detection results to adaptively perform multiple intra-frame processes, including inter-field calculations and intra-field band limiting of color signals. An intra-frame YC separation circuit is provided which performs switching processing and outputs an intra-frame YC-separated Y signal and an intra-frame YC-separated C signal.

Another invention, the motion adaptive YC separation filter, has the following features: (2) When the motion detection circuit detects a moving image, it locally detects the correlation between frames, and uses the detection results to perform interfield calculations and brightness. A device equipped with an intra-frame YC separation circuit that adaptively switches between multiple intra-frame processes including intra-field band limiting of the signal and outputs an intra-frame YC-separated Y signal and an intra-frame YC-separated C signal. It is.

[Operation] The intra-frame YC separation circuit of the present invention detects the correlation between frames when the motion detection circuit determines that it is a moving image, and selects three types of intra-frame YC based on the magnitude of the correlation.
By selecting one of the separation circuits, an intra-frame YC separated Y signal and an intra-frame YC separated C signal are output.

[Embodiment] An embodiment of the motion adaptive YC separation filter of the present invention will be shown below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the invention, and in this FIG. 1, the intra-field YC separation circuit 4 in FIG. 1O is replaced with an intra-frame YC separation circuit 50, and other This part has been explained using the conventional example, so it will be omitted.

A detailed block diagram of a first embodiment of the intra-frame YC separation circuit 50 in FIG. 1 is shown in FIG.

In FIG. 2, a V signal 101 is input to the input terminal 11. This V signal 101 includes a 263-line delay circuit 14, an l-line delay circuit 23, and a 2-pixel delay circuit 25.
is input to the input terminal of

V delayed by 263 lines by the 263 line delay circuit 14
The signal is transmitted through the 2 pixel delay circuit 15 and the 262 line delay circuit 1.
6 input terminals, respectively.

The V signal delayed by two pixels by the two-pixel delay circuit 15 is input to the first input terminals of subtracters 20.21 and 22.37, respectively. The ■ signal delayed by 262 lines by the 262-line delay circuit 16 is sent to the input terminal of the 4-pixel delay circuit F, the input terminal of the l-line delay circuit 18, the first input terminal of the subtracter 26, and the subtracter 20.
is input to the second input terminal of. 4 pixel delay circuit 17
The pixel-delayed V signal is input to the second input terminal of the subtractor 21 and the first input terminal of the subtractor 27. The V signal delayed by one line in the l-line delay circuit 18 is sent to the two-pixel delay circuit 1.
It is input to the input terminal of 9. The V signal delayed by two pixels by the two-pixel delay circuit 19 is input to the second input terminal of the subtracter 22 and the first input terminal of the subtracter 28 .

The output signal of the subtracter 20 is input to a first input terminal of the signal selection circuit 33. The output signal of the subtracter 21 is input to the second input terminal of the signal selection circuit 29. The output signal of the subtracter 22 is input to the third input terminal of the signal selection circuit 29.

The V signal delayed by one line in the one line delay circuit 23 is 4
The signal is input to the input terminal of the pixel delay circuit 24 and the second input terminal of the subtracter 27 . The V signal delayed by 4 pixels by the 4-pixel delay circuit 24 is input to the second input terminal of the subtracter 26 . The V signal delayed by 2 pixels by the 2-pixel delay circuit 25 is sent to the subtracter 28
is inputted to the second input terminal of.

The output of the subtracter 26 is input to the input terminal of the absolute value circuit 29, the output of the subtractor 27 is input to the input terminal of the absolute value circuit 30, and the output of the subtractor 28 is input to the input terminal of the absolute value circuit 31.

The output of the absolute value circuit 29 is connected to the first input terminal of the minimum value selection circuit 32, the output of the absolute value circuit 30 is connected to the second input terminal of the minimum value selection circuit 32, and the output of the absolute value circuit 31 is connected to the minimum value selection circuit 32. They are respectively input to third input terminals of the circuit 32.

The output of the minimum value selection circuit 32 is input to the fourth input terminal of the signal selection circuit 33, thereby selectively controlling the first to third inputs.

The output of the signal selection circuit 33 is input to the input terminal of the one-line delay circuit 34 and the first input terminal of the subtracter 35. The output of the l-line delay circuit 34 is input to the second input terminal of the subtracter 35. The output of the subtracter 35 is input to the input terminal of the BPF 36.

The output of the BPF 36 is input to the second input terminal of the subtracter 37 and outputted from the output terminal 13 as an intra-frame YC separated C signal 113. The output of the subtracter 33 is outputted from the output terminal 12 as an intra-frame YC separated Y signal 112.

Next, the operation will be explained.

The horizontal direction of the screen is the X axis, and the vertical direction of the screen is the y axis.
If the t-axis, which is the time axis, is taken in the direction perpendicular to the plane composed of the axes, a three-dimensional space-time can be considered that can be composed of the X-axis, y-axis, and t-axis.

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 increment scanning lines, with dashed lines indicating one field and solid lines indicating that the color subcarriers are in phase.

Furthermore, the solid lines and broken lines in FIG. 5(b) indicate the scanning lines of the n field and the n-1 field, respectively, and the four types of marks on the scanning lines are rOJ, "・", "△", and "mu". is the color subcarrier frequency fsc (=3.58MH
The color subcarriers when digitized at four times z) indicate sample points in which the phase is the same.

In addition, the solid line and broken line in FIG. 5(C) are respectively n+1
It shows the scanning lines of field and n field, and the four types of marks "○", ".", "Δ", and "mu" on the scanning lines are the same as in FIG. 5(b).

Now, if the sample point of interest is represented by "◎", then in field n, which is the same field, the color subcarrier phase is 1800 at around 2 sample points and four points a, b, c, and d above and below l line.
It's different.

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 constructed.

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 around the sample point on the l line or the two sample points one line below. Inter-field YC separation is possible by calculating any one of these three points A, B, and B with the point of interest.

Furthermore, considering the μ-axis which is the horizontal frequency axis, the ν-axis which is the vertical frequency axis, and the f-axis which is the time-frequency axis as the frequency axes corresponding to the above X-axis, y-axis, and t-axis, we consider the μ-axis which is orthogonal to each other , ν axis, and f axis can be considered.

FIG. 6 shows a projection of the 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 above three-dimensional frequency space viewed from the positive direction of the μ axis.

FIGS. 6(a) to 6(c) show the spectral distribution of the V signal on a three-dimensional frequency space. Figure 6(a)
As seen from ~(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 the color subcarrier frequency fsc, and the ■signal ゛ and Q signal are orthogonal two-phase modulation. Therefore, Figures 6(a) to (C)
It is located in four spaces such as .

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 rises with time in FIG. 5(a).

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; It was not possible to add directional band limits.

Therefore, the frequency space in which the Y 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, the band of the Y signal in a moving image can be expanded.

In FIG. 5(b), among the n-1 fields, there are two sample points A, B, and A, which are in the vicinity of the sample point of interest "◎" and whose color subcarrier phases differ by 180 degrees. Inter-field YC separation is possible by calculation with any of these three points.

First, it is possible to extract high-frequency components on the three-dimensional frequency space including the C signal based on the difference between the sample point of interest "◎" and the sample point "." A in FIG. 5(b). In addition to this, the 1-line delay circuit 34, subtracter 35, and BPF 36 in FIG.
A C signal is obtained by passing the signal through a two-dimensional BPF consisting of.

Furthermore, the Y signal is obtained by subtracting the C signal from the V signal. This is referred to as inter-field YC separation A.

Figures 7(a) to (c) are the same as Figures 6(a) to (c) (
It represents a three-dimensional frequency space, in which a Y signal and a C signal obtained by interfield YC separation A exist.

Second, it is possible to extract high-frequency components on the three-dimensional frequency space including the C signal based on the difference between the sample point of interest "◎" and the sample point "." A in FIG. 5(b). Add to this the above 2
Passing through the dimensional BPF yields the C signal. Also V
The Y signal is obtained by subtracting the C signal from the signal. This is referred to as inter-field YC separation B.

Figures 8(a) to (c) also have inter-field YC separation B.
It shows the frequency space in which the Y signal and C signal obtained by the above exist. Looking at FIGS. 8(a) to (c), it appears that the separated Y signal contains a portion of the C signal, but since the Y signal and the C signal have a strong correlation with each other, the Y signal contains the C signal. Very few signals are included.

Thirdly, the high frequency component on the three-dimensional frequency space including the C signal can be extracted from the difference between the sample point of interest "◎" and the sample point "." in FIG. 5(b). Add to this the above 2
Passing through the dimensional BPF yields the C signal. Also V
The Y signal is obtained by subtracting the C signal from the signal. This is referred to as inter-field YC separation C.

Similarly, in FIGS. 9(a) to 9(c), YC separation C between fields
It shows the frequency space in which the Y signal and C signal obtained by the above exist. Looking at Figures 9(a) to (c), it appears that the separated Y signal contains a portion of the C signal, but for the same reason as in Figure 8, the Y signal contains the C signal. are extremely rare. In order to adaptively switch and control these three types of inter-field YC separation, it is necessary to detect the correlation of images in the direction connecting the sample point of interest "◎" and the sample points "." A, B, and A. Therefore, the correlation between the images in each direction is calculated between the sample points ``・'' in the n-1 field that sandwich the sample point of interest ``◎'', and the sample points ``A, I, and n+1 field'' in the n+1 field.
・It may be detected by calculating the force, force, and force and use it as a control signal.

Next, the operation of the intra-frame YC separation circuit configured as shown in FIG. 2 will be explained.

In the present invention, when the motion detection circuit 80 determines that the image is a moving image, the optimum intra-frame YC separation including three types of inter-field operations is used as moving image processing instead of the intra-field YC separation. It is characterized by

In FIG. 2, a V signal 10 input from an input terminal 11
1 is delayed by 263 lines in the 263-line delay circuit 14, further delayed by 2 pixels in the 2-pixel delay circuit 15, and
The 62-line delay circuit 16 delays the signal by 262 lines.

The V signal delayed by 2 pixels in the 2-pixel delay circuit 15 and 262
By subtracting the output of the line delay circuit 16 using a subtracter 20, an inter-field difference for inter-field YC separation C is obtained.

By subtracting the V signal delayed by 2 pixels by the 2-pixel delay circuit 15 and the output of the 4-pixel delay circuit 17 by the subtracter 21, an inter-field difference for inter-field YC separation B is obtained.

By subtracting the V signal delayed by two pixels by the two-pixel delay circuit 15 and the output of the two-pixel delay circuit 19 by the subtracter 22, an inter-field difference for inter-field YC separation A is obtained.

The above three types of inter-field differences are input to the signal selection circuit 33, and selected by the output of the minimum value selection circuit 32, which will be described later.

Output of 262-line delay circuit 16 and 4-pixel delay circuit 24
The subtracter 26 subtracts the output from the absolute value circuit 2.
9 to detect the correlation between the sample points "." in FIGS. 5(b) and 5(c) and the force. The output of the 4-pixel delay circuit 17 and the output of the 1-line delay circuit 23 are subtracted by the subtracter 27, and further converted into absolute values by the absolute value circuit 30, resulting in the sample points "." in FIGS. 5(b) and 5(c). Detect the correlation between A and O. The output of the 2-pixel delay circuit 19 and the output of the 2-pixel delay circuit 25 are subtracted by a subtracter 28, and further converted into an absolute value by an absolute value circuit 31, as shown in FIG.
b) Detect the correlation between the sample point "・"a and the engineering in (c).

The minimum value selection circuit 32 selects the minimum one (the one with the maximum correlation detection amount) among the above-mentioned 13 types of absolute value outputs, and controls the signal selection circuit 33.

That is, the signal selection circuit 33 selects the output of the subtracter 20 when the output of the absolute value circuit 29 is the minimum, selects the output of the subtracter 21 when the output of the absolute value circuit 30 is the minimum, and selects the output of the subtracter 21 from the absolute value circuit 31.
When the output of the subtracter 22 is the minimum, the output of the subtracter 22 is selected.

Further, the output of the signal selection circuit 33 is passed through a one-line delay circuit 34 and a subtracter 35 in which only the vertical high frequency component is passed, and the BP
Only the horizontal high frequency components are passed by F36. That is, the output of the signal selection circuit 33 is two-dimensionally band-limited by a two-dimensional BPF to become an intra-frame YC separated C signal 113.

The subtracter 37 selects V, which is the output of the two-pixel delay circuit 15.
By subtracting the intraframe YC separated C signal 113 from the signal, an intraframe YC separated Y signal 112 can be obtained.

In addition, in FIG. 2, the one-line delay circuit 34 and subtracter 35 are used to pass only the vertical high-frequency component;
A similar effect can be obtained by calculating this using a plurality of one-line delay circuits.

FIG. 3 shows Y in the frame in FIG. 1, which is the present invention.
FIG. 4 is a detailed block diagram of a second embodiment of the C separation 50;

In this figure, the only difference from FIG. 2 is the method of intra-field band limiting. Of the intra-frame YC separation circuit having the configuration shown in FIG. 3, only the intra-field band limitation different from that in FIG. 2 will be explained. In FIG. 3, the same parts as in FIG. 2 are given the same numbers.

The output of the signal selection circuit 33 is a three-dimensional frequency space high frequency component obtained by one of three types of inter-field calculations. Therefore, the output of the signal selection circuit 33 is subtracted by the subtracter 38 from the V signal that is the output of the two-pixel delay circuit 15, and a three-dimensional frequency space low-frequency component in the direction in which the correlation is detected is obtained. The obtained three-dimensional frequency space low frequency component is input to the first input terminal of the adder 41. Further, the output of the signal selection circuit 33 passes only the vertical low frequency component through the one line delay circuit 34 and the adder 39, and passes only the vertical high frequency component through the l line delay circuit 34 and the subtracter 35. The output of the subtracter 53 is further passed through an LPF 40 in which only the horizontal low frequency component is passed, and is input to the second input terminal of the adder 41 . On the other hand, the output of the adder 39 is input to the second input terminal of the adder 41, and the output of the adder 41 becomes a signal obtained by removing the C signal from the high frequency component in the three-dimensional frequency space. The adder 42 adds the three-dimensional frequency spatial low frequency component to obtain an intra-frame YC separated Y signal 112.

The subtracter 42 selects V, which is the output of the two-pixel delay circuit 15.
By subtracting the intraframe YC separated Y signal 112 from the signal, an intraframe YC separated C signal 113 can be obtained.

FIG. 4 shows Y in the frame in FIG. 1, which is the present invention.
FIG. 4 is a detailed block diagram of a third embodiment of the C separation 50;

The difference between FIG. 4 and FIG. 2 is that in addition to the intra-frame YC separation circuit that includes three types of inter-field calculations and intra-field band limiting of the color signal, there is also an intra-frame YC separation circuit that uses only the intra-field band limiting of the color signal. The point is that the optimal one is used from among the four intra-frame YC separation circuits. Of the intra-frame VC separation circuits having the configuration shown in FIG. 4, only the inter-frame correlation detection circuit that is different from that in FIG. 2 will be described. In FIG. 4, the same parts as in FIG. 2 are given the same numbers.

The output of the two-pixel delay circuit 15 is the subtracter 20.2122.3
The signal is input to the first input terminal of the signal selection circuit 45 . Subtractor 20.21,
The outputs of 22 are input to the second, third, and fourth input terminals of the signal selection circuit 45, respectively. Also, the absolute value circuit 29
The outputs of are input to the first inputs of the maximum value selection circuit 43 and the minimum value selection circuit 32, respectively. The output of the absolute value circuit 30 is input to second inputs of the maximum value selection circuit 43 and the minimum value selection circuit 32, respectively. The output of the absolute value circuit 31 is input to the third input of the maximum value selection circuit 43 and the minimum value selection circuit 32, respectively. The output of the maximum value selection circuit 43 is input to the first input terminal of the threshold value determination circuit 44. The output of the minimum value selection circuit 32 is input to the second input terminal of the threshold value determination circuit 44 and the fifth input terminal of the signal selection circuit 45.

The output of the threshold value judgment circuit 44 is the sixth signal selection circuit 45.
is input to the input terminal of. If the maximum value of the three types of inter-frame correlations is smaller than the first threshold α, or if the minimum value of the three types of inter-frame correlations is the second
is larger than the threshold value β, the signal selection circuit 45
Control is performed to select the output of the pixel delay circuit 15. Since the configuration after the signal selection circuit 45 is the same as that in FIG.
In this case, YC separation is performed only by intra-field band limiting. On the other hand, in the threshold value determination circuit 44, 3
The maximum value of the inter-frame correlations of three types is greater than the first threshold α, or the minimum value of the three types of inter-frame correlations is the second
If the output of the absolute value circuit 29 is the minimum, the signal selection circuit 45 uses the output of the minimum value selection circuit 32 to select the output of the subtracter 20 from the absolute value circuit 32. When the output of the absolute value circuit 30 is the minimum, the output of the subtracter 21 is selected, and when the output of the absolute value circuit 30 is the minimum, the output of the subtracter 21 is selected. In this case, as in the embodiment shown in FIG. 2, intra-frame YC separation including inter-field calculation and intra-field band limiting of color signals is adaptively performed.

However, it is assumed that there is a relationship between α and β.

Also, in the embodiment shown in FIG. 3, the maximum value selection circuit 43, the threshold value determination circuit 44, and the signal selection circuit 45 are used as in FIG. Intra-frame YC separation can be adaptively controlled.

In addition, in all the embodiments shown in FIGS. 2 to 4, inter-field calculations are performed between n fields and n −1 fields in order to configure the YC separation filter;
Inter-field operations may be performed between 1 field and n fields. That is, according to the results of three types of inter-frame correlation detection, a similar intra-frame YC separation circuit is constructed by calculation between the sample point of interest "◎" and the sample point "・" in the n+1 field. can.

[Effects of the Invention] As described above, according to the present invention, (1) when a motion detection circuit detects a moving image, the intra-frame YC separation circuit locally detects correlation between frames and performs inter-field calculation. Three types including in-field band limit of color signal,
Alternatively, since the configuration is configured to perform YC separation within four types of frames, optimal YC separation can be performed using image correlation in video processing with a motion adaptive YC separation filter, and resolution degradation can be avoided even in videos. This has the effect of configuring a motion adaptive YC separation filter that performs less YC separation.

Furthermore, (2) when the motion detection circuit detects a moving image, the intra-frame YC separation circuit locally detects the correlation between frames and performs three types of calculations including inter-field calculation and intra-field band limitation of the luminance signal; Since it is configured to perform YC separation within four types of frames, optimal YC separation can be performed using image correlation in video processing using a motion adaptive YC separation filter, and there is little resolution degradation even in videos. This has the effect of configuring a motion adaptive YC separation filter that performs YC separation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a motion adaptive YC separation filter according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a detailed configuration of a first embodiment of the intra-frame YC separation circuit in the embodiment of FIG. 3 is a block diagram showing a detailed configuration of a second embodiment of the intra-frame YC separation circuit in the embodiment of FIG. 1, and FIG. 4 is a block diagram showing the intra-frame YC separation circuit in the embodiment of FIG. 1. FIG. 5(a) is a block diagram showing the detailed configuration of the third embodiment of the invention. In a three-dimensional space-time, the color subcarrier is four times as large as the digitized V signal array, which is composed of the t-axis and the y-axis. Figures 5(b) and 5(c) are plan views showing the arrangement of the signals on the y-axis and y-axis, and Figure 6(
Figure 6 (a) is a diagram of the spectral distribution of the V signal in a three-dimensional frequency space viewed from an oblique direction, Figure 6 (b) is a diagram of the same spectrum distribution viewed from the negative direction of the f-axis, and Figure 6 (C) is a diagram of the spectrum distribution of the V signal viewed from an oblique direction. FIG. 7(a) shows the spectral distribution of the Y signal and C signal obtained by the first inter-field YC separation according to the present invention in a three-dimensional frequency space. Figure 7 (i) is a diagram of the same spectrum distribution seen from the negative direction of the f axis, Figure 7 (c).
is a diagram of the same spectral distribution seen from the positive direction of the μ axis, and FIG. 8 (ao) is a diagram of the second interfield YC according to the present invention.
Figure 8(b) is a diagram of the spectral distribution of the Y signal and C signal obtained by separation viewed from an oblique direction on a three-dimensional frequency space. 8
Figure (c) is a diagram of the spectral distribution as seen above from the positive direction of the μ axis, and Figure 9 (a) is the spectral distribution of the Y signal and C signal obtained by the third inter-field YC separation according to the present invention. Figure 9, a diagram viewed from an oblique direction on a three-dimensional frequency space (
b) is a diagram of the above spectrum distribution viewed from the negative direction of the f axis, Figure 9 (C) is a diagram of the same spectrum distribution as seen from the positive direction of the μ axis, and Figure 10 is a diagram of the conventional motion adaptive YC. A block diagram of the separation filter, Fig. 11 is the motion adaptive type Y shown in Fig. 1O.
FIG. 12 is a block diagram showing the detailed configuration of the Y signal motion detection circuit in the C separation filter; FIG. 12 is a block diagram showing the detailed configuration of the C signal motion detection circuit in the motion adaptive YC separation filter of FIG. 10; FIG. 10 is a block diagram showing a detailed configuration of the interframe YC separation circuit in the motion adaptive YC separation filter of FIG. 1O, and FIG. 14 is a detailed configuration of the intrafield YC separation circuit of the motion adaptive YC separation filter of FIG. 10. FIG. 15 is a block diagram showing another example of the conventional C signal motion detection circuit. 5... Inter-frame YC separation circuit, 6... Y signal motion detection circuit, 7... C signal motion detection circuit, 8... Synthesis circuit, 9... Y signal mixing circuit, 10... C signal mixing circuit, 50...Intra-frame YC separation circuit, 80...
Motion detection circuit. In addition, in the figures, the same reference numerals indicate the same or corresponding 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 performs separation using interframe correlation when the motion detection circuit detects a still image, and outputs an interframe luminance signal, a chrominance signal, and a separated chrominance signal. When the interframe luminance signal color signal separation circuit and the motion detection circuit detect a moving image, the correlation is locally detected by the difference at the point where the phase of the color subcarrier is the same between frames, and the correlation is detected based on the detection result. , performs processing that adaptively switches multiple intra-frame processes including inter-field calculations and intra-field band limiting of color signals, outputs intra-frame luminance signals, color signals, separated color signals, and outputs the original composite color signals. An intra-frame luminance signal chrominance signal separation circuit that outputs an intra-frame luminance signal chrominance signal separated luminance signal by subtracting the intra-frame luminance signal chrominance signal separation color signal from the television signal; a luminance signal mixing circuit that mixes the luminance signal and chrominance signal separated luminance signal and the intra-frame luminance signal chrominance signal separated luminance signal to output a motion-adaptive luminance signal chrominance signal separated luminance signal; The motion adaptation device is characterized by comprising a color signal mixing circuit that mixes the inter-frame luminance signal, chrominance signal, and separated color signal and the intra-frame luminance signal, chrominance signal, and the separated color signal to output a motion-adaptive luminance signal, chrominance signal, and separated chrominance signal. type luminance signal chrominance signal separation filter. (2) When the motion detection circuit detects a moving image instead of the above-mentioned intra-frame luminance signal and color signal separation circuit, the correlation is calculated by obtaining the difference at the point where the phase of the color subcarrier is the same between frames. Local detection is performed, and based on the detection result, processing is performed to adaptively switch between multiple intra-frame processes including inter-field calculations and intra-field band limiting of luminance signals, and intra-frame luminance signal color signal separation color processing is performed. Replaced with an intra-frame luminance signal chrominance signal separation circuit that outputs an intra-frame luminance signal chrominance signal separation signal and also outputs an intra-frame luminance signal chrominance signal separation luminance signal by subtracting the intra-frame luminance signal chrominance signal separation color signal from the original composite color television signal. 2. The motion adaptive luminance signal/chrominance signal separation filter according to claim 1.