JPH03274889A - Motion adaptive type luminance signal/chrominance signal separating filter - Google Patents

Abstract

PURPOSE:To execute the YC separation whose resolution is scarcely degraded by constituting the filter so that at the time of detecting an animated picture by a motion detecting circuit, a correlation between fields is detected locally in an in-three-field YC separating circuit, and plural inter-field operations containing an inter-three-field operation is selected adaptively. CONSTITUTION:A minimum value selecting circuit 35 detects the smallest one (the correlation is maximum) from in three kinds of absolute value inputs. That is, the minimum value selecting circuit 35 controls a signal selecting circuit 36 so that an output of a low-pass filter 26, an output of an adder 27, and an output of an adder 28 are selected when an output of an absolute value circuit 32 is minimum, when an output of an absolute value circuit 33 is minimum, and an output of an absolute value circuit 34 is minimum, respectively. An output of an adder 37 is outputted from an output terminal 12 as an in-three- field YC separating Y signal 112. Also, by subtracting the output of the adder 37 from an output of a two-picture element delaying circuit 19 by a subtracter 38, an in-three-field YC separating C signal 113 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention is 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. 15 is a block diagram showing an example of a conventional motion adaptive YC separation filter.

In the same figure, input terminal l has an NTSC system V signal 1.
01 is input and applied to the input terminals of the intra-field YC separation circuit 4, the inter-frame YC separation circuit 5, the Y signal motion detection circuit 6, and the C signal motion detection circuit 7, respectively.

In the intra-field YC separation circuit 4, the intra-field YC separated Y signal 102 and the intra-field YC separated C signal 103, which are YC-separated by an intra-field filter (not shown), are respectively input to the first Y-signal mixing circuit 9. Input end and C
It is input to the first input terminal of the signal mixing circuit 10.

In addition, in the interframe YC separation circuit 5, the interframe YC separated by the interframe filter (not shown) is
Separated Y signal 104 and interframe YC separated C signal 105
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 one input terminal of the synthesis circuit 8, and the C signal motion amount detected by the C signal motion detection circuit 7 is inputted to one input terminal of the synthesis circuit 8. The signal 107 shown is input to the other input terminal of the combining 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 90.

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 10 is sent out from the output terminal 3.

Next, the operation will be explained.

When the motion detection circuit 90 separates the signal 101 into Y and C, the motion detection circuit 90 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 in the l-frame delay circuit 53 and the directly inputted V signal 101 are subtracted by the subtracter 54 to obtain ■signal 1.
01 is calculated, and passed through a low-pass filter (hereinafter referred to as LPF) 55, its absolute value is calculated in an absolute value circuit 56, and this absolute value is converted into a low-frequency component of the Y signal in a non-linear conversion circuit 57. The signal 106 is converted into a signal 106 indicating the amount of movement, and is output 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 62 as shown in FIG. 17, and a directly inputted V signal. 101 is subtracted by a subtracter 63 to obtain a two-frame difference, which is passed through a band pass filter (hereinafter referred to as BPF) 64, its absolute value is determined by an absolute value circuit 65, and this absolute value is converted to a nonlinear The conversion circuit 66 converts the C signal into a signal 107 indicating the amount of movement, and outputs the signal 107 from the output terminal 61.

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 71 by one frame by one frame delay circuit 74 and the directly inputted V signal 101, as shown in FIG. 18, for example. The YF signal 104 is added by a subtracter 75 to obtain the l-frame sum, and is output to the output terminal 72, and the YF signal 104 is subtracted from the V signal 101 input from the input terminal 71 by a subtracter 76. As a result, the CF signal 105 is extracted and outputted from the output terminal 73.

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. 19, the V signal 101 inputted from the input terminal 81 is delayed by one line in the one line delay circuit 84, and the V signal 101 directly inputted is added in the adder 85, and the l-line sum is added. , and extract the Yf signal 102,
The Yf signal 102 is outputted from the output end 82, and the Cf signal 103 is extracted by subtracting the Yf signal 102 from the -signal 101 inputted from the input end 81 in the subtracter 86, and is outputted from the output end 83.

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 10 to perform the following calculations, and outputs a motion adaptive YC separated C signal 110 from the output terminal 3.

C=kCf+ (1-k)CF where, Cf: In-field YC separation 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 67 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 68, delayed by two frames by a two-frame delay circuit 62, and then divided into two frames by a subtracter 63. By subtracting the output of the delay circuit 62 and the output of the time division multiplexing circuit 68, a two-frame difference is obtained.

The two-frame difference is passed through an LPF 69 to remove the Y signal component, an absolute value circuit 65 takes the absolute value, and a nonlinear conversion circuit 66 performs nonlinear conversion to obtain the motion detection amount of the C signal.
07 can be sent out from the output end 61.

[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 flaw signal Cf signal and the YF multiplied signal CF signal from the interframe YC separation circuit 5 are mixed.

Therefore, since the filter characteristics for still images and the filter characteristics for videos are completely different, there is an extreme change in resolution when moving from a still image to a video or from a video to a still image, so video processing There was a problem in that the image quality deteriorated significantly over time.

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 Problems] The motion adaptive YC separation filter according to the present invention locally detects the correlation between fields when the motion detection circuit detects a moving image, and uses the detection result to determine the correlation between three fields. A 3-field YC signal that outputs a 3-field YC-separated Y signal and a 3-field YC-separated C signal by adaptively switching between multiple inter-field processes including calculations of
A C separation circuit is provided.

[Function] The 3-field YC separation circuit of the present invention detects the correlation between fields when the motion detection circuit determines that it is a moving image, and selects three types of 3-field YC separation circuits depending on the magnitude of the correlation. By selecting either, 3-field YC separated Y signal and 3-field YC
Outputs a separated C signal.

[Example] Hereinafter, this invention will be explained based on the drawings.

FIG. 1 is a block diagram showing a motion adaptive YC separation filter according to an embodiment of the present invention. This figure 1 is
The part of the intra-field YC separation circuit 4 in FIG.
There is a replacement for the intra-field YC separation circuit 50, and the other parts have been explained in the conventional example, so a description thereof will be omitted.

A detailed block diagram of an embodiment of the three-field YC separation circuit 50 in FIG. 1 is shown in FIG. In the same figure,
A V signal 101 is input to the input terminal 11 . 14.2
1 is a 262-line delay circuit, 15 is an l-line delay circuit,
16.19.20 is a 2 pixel delay circuit, 17.22 is a 4 pixel delay circuit 18.24.25.38 is a subtracter, 23.2
728.37 is an adder.

26.29.30.31 is a low-pass filter with a passband of 2.1MHz or less, 32.33.34 is an absolute value circuit that outputs an absolute value, and 35 determines the minimum value for three inputs. 36 is a signal selection circuit that selects and outputs one of three inputs. The output of the adder 37 is outputted from the output terminal 12 as a 3-field YC separated Y signal 112, and is also output from the subtracter 3.
The output of 8 is output from the output terminal 13 as a 3-field YC separated C signal 113.

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 4 is a diagram representing three-dimensional space-time, and Figure 4 (a
) is a plane composed of the t-axis and the y-axis, and FIG. 4(b) is a plane composed of the X-axis and the y-axis. FIG. 4(a) also shows interlaced scan lines, with dashed lines indicating one field and solid lines indicating that the color subcarriers are in phase.

In addition, the solid lines and broken lines in FIG. 4(b) indicate the scanning lines of the n field and the n-1 field, respectively, and there are four types of ``◎'', ``・'', ``△'', and ``mu'' on the scanning lines. The mark indicates the V signal at 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.

Now, if the sample point of interest is represented by "◎", the color subcarrier phase is 180 degrees at around 2 sample points in the same field, field n, and at the four points a, b, c, and d above and below the ■ line.
It's different.

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

Further, as shown in FIG. 4(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. 4(b), in the n-1 field one field before the sample point of interest, the phase is opposite around the sample point on one line or two sample points below the l line. Inter-field YC separation is possible by calculating any one of these three points A, B, and B with the point of interest.

In addition, as frequency axes corresponding to the above X-axis, ν-axis, and t-axis, consider 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, and the μ-axis which are perpendicular to each other. , ν axis, and f axis can be considered.

FIG. 5 shows a projection of the three-dimensional frequency space. FIG. 5(a) is a diagram of the three-dimensional frequency space viewed from an oblique direction, FIG. 5(b) is a diagram of the three-dimensional frequency space viewed from the negative direction of the f-axis, and FIG. 5(C) is a diagram of the above three-dimensional frequency space viewed from the positive direction of the μ axis.

FIGS. 5(a) to 5(C) show the spectral distribution of the V signal on a three-dimensional frequency space. Figure 5(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 obtained by orthogonal two-phase modulation of the I signal and the C signal at the color subcarrier frequency fsc. Therefore, they are located in four spaces as shown in FIGS. 5(a) to 5(C). However, Fig. 5 (
When the V signal is viewed on the μ axis as shown in 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. 4(b).

Nevertheless, in the conventional example, when motion of an image is detected, YC separation is performed using correlation within the field, so band limitation in the μ-axis and ν-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 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.

As mentioned above, the C signal exists only in the second and fourth quadrants in Fig. 5(C), so the difference between the sample point of interest "◎" and the sample point A "・" in Fig. 4(b) is By calculation, it is possible to extract low frequency components on the three-dimensional frequency space that do not include the C signal. This low-pass filter is composed of a 262-line delay circuit 14, a 1-line delay circuit 15, and an adder 23, and the output of the adder 23 becomes a low frequency component. A bandpass filter is configured by the 262-line delay circuit 14, the 1-line delay circuit 15, and the subtracter 18, and the output of the subtracter 18 becomes a high frequency component on a three-dimensional frequency space including the C signal. By passing this high frequency component through the horizontal low pass filter 26, it is possible to obtain a high frequency component of the Y signal that does not include the C signal. The output of the low-pass filter 26 is input to a signal selection circuit 36, and when selected by the signal selection circuit 36, it is added to the output of the adder 23 by an adder 37, and a Y signal containing no C signal is output. .

Furthermore, the C signal can be obtained by subtracting the Y signal from the V signal. This is referred to as 3-field YC separation A.

Figures 6(a) to (c), like Figures 5(a) to (c), represent a three-dimensional frequency space, and Y within the three fields.
It shows the frequency space in which the Y signal and C signal obtained by C separation A exist.

Next, for the high frequency component obtained from the output of the subtractor 18, the C signal is removed by performing an operation between the sample point of interest "◎" and the sample point "・" in FIG. 4(b). I can do it. By performing calculations on the two sample points in the adder 27, high frequency components of the Y signal that do not include the C signal are extracted. This high frequency component is transmitted to the signal selection circuit 36.
When the signal is input to the signal selection circuit 36 and selected by the signal selection circuit 36, it is added to the output of the adder 23 by the adder 37, and a Y signal containing no C signal is output. Furthermore, the C signal can be obtained by subtracting the Y signal from the V signal. This is referred to as 3-field YC separation B.

FIGS. 7(a) to 7(c) show the frequency space in which the Y signal and the C signal exist, obtained by YC separation B within three fields.

Next, for the high frequency component obtained from the output of the subtracter 18, the C signal is removed by performing an operation between the sample point of interest "◎" and the sample point A "・" in FIG. 4(b). I can do it. By performing calculations on the two sample points in the adder 27, high frequency components of the Y signal that do not include the C signal are extracted. This high frequency component is transmitted to the signal selection circuit 36.
When the signal is input to the signal selection circuit 36 and selected by the signal selection circuit 36, it is added to the output of the adder 23 by the adder 37, and a Y signal containing no C signal is output. Furthermore, the C signal can be obtained by subtracting the Y signal from the V signal. This is referred to as 3-field YC separation C.

Figures 8(a) to (c') show YC separation C within 3 fields.
It shows the frequency space in which the Y signal and C signal obtained by the above exist.

In order to adaptively switch and control these three types of 3-field YC separation, the sample point of interest “◎
It is necessary to detect the correlation between `` and sample points ``・'' A, B, and tsu. The correlation between the sample point ``◎'' of interest and the sample points ``・'' A, I, and A in Fig. 4 (b) is determined by passing the respective differences through a low-pass filter, and then The sample point of interest “◎” and the sample point “A” in Fig. 4(b) detected by the frequency component are
” is detected as follows. The output of the subtracter 18 is delayed by a two-pixel delay circuit 20 and then passed through a low-pass filter 29 to extract horizontal low frequency components.

The output of the low-pass filter 29 is inputted as an absolute value by the absolute value circuit 32 to the minimum value selection circuit 35, and the fourth
A correlation is detected between the sample point of interest "◎" and the sample point A "." in FIG. 3(b).

The solid line portion in FIG. 9(a) to (c) is the low-pass filter 2.
This is a three-dimensional frequency domain obtained from the output of 9, and is a frequency domain in which the spread of the spectrum of the Y signal is detected because the three-field YC separation A is not selected.

Further, the correlation between the sample point of interest "◎" and the sample point "." in FIG. 4(b) is detected as follows. Calculations on the two sample points are performed by a subtracter 24, and the output of the subtracter 24 is passed through a low pass filter 30 to extract horizontal low frequency components.

The output of the low-pass filter 30 is inputted as an absolute value by the absolute value circuit 33 to the minimum value selection circuit 35, and the fourth
A correlation is detected between the sample point of interest "◎" and the sample point "." in FIG. 3(b).

The solid line portion in FIGS. 10(a) to (c) is the three-dimensional frequency domain obtained from the output of the low-pass filter 30, and since YC separation B within three fields is not selected, the spread of the spectrum of the Y signal is detected. It is in the frequency domain.

Further, the correlation between the sample point of interest "◎" and the sample point A "." in FIG. 4(b) is detected as follows. Calculation of two sample points is performed by a subtracter 25, and the subtracter 25
The output is passed through a low pass filter 31, and horizontal low frequency components are extracted. The output of the low-pass filter 31 is input to the minimum value selection circuit 35 as an absolute value by the absolute value circuit 34, and the sample point of interest in FIG.
A correlation between “◎” and sample point A “・” is detected.

The solid line portion in FIG. 1I (a) to (c) is the three-dimensional frequency domain obtained from the output of the low-pass filter 3I, and the spread of the spectrum of the Y signal is detected because YC separation C within three fields is not selected. It is in the frequency domain.

The minimum value selection circuit 35 detects the minimum value (the value with the maximum correlation) from among the three types of absolute value inputs. That is, the minimum value selection circuit 35 selects the output of the low-pass filter 26 when the output of the absolute value circuit 32 is the minimum, and the output of the adder 27 when the output of the absolute value circuit 33 is the minimum.
The signal selection circuit 36 is controlled to select the output of the adder 28 when the output of the adder 4 is the minimum. The output of adder 37 is 3
It is output from the output terminal 12 as an intra-field YC separated Y signal 112. Further, by subtracting the output of the adder 37 from the output of the 2-pixel delay circuit 19 by the subtracter 38, a 3-field YC separated C signal 113 is obtained.

FIG. 3 is a detailed block diagram of another embodiment of the three-field YC separation 50 in FIG. 1 according to the present invention.

In FIG. 3, 39 is a two-pixel delay circuit, 40 is a subtracter, 41.42 is an adder, 43 is a low-pass filter with a passband of 2.1MHz or less, and 4445 is a passband of 1.1MHz or more. The bandpass filter 46 is a maximum value selection circuit that determines the maximum value of three inputs and outputs a control signal.

Next, the operation will be explained.

The only difference in FIG. 3 from FIG. 2 is the method of detecting correlation between fields.

In Figure 4(b), the sample point of interest “◎” and the sample point A “・
” is detected as follows.

In Figure 4(b), the noted sample point “◎” and the sample point “○”
'' is performed by the subtracter 40, and high frequency components on the three-dimensional frequency space are extracted.

From the output of the subtracter 40, a horizontal low frequency component is extracted by a low pass filter 43. Low pass filter 4
The output of 3 is inputted as an absolute value by the absolute value circuit 32 to the maximum value selection circuit 46, and the correlation between the sample point of interest "◎" and the sample point A "." in FIG. 4(b) is detected. .

The solid line portion in Fig. 12 (a) to (c) is the low-pass filter 4.
This is a three-dimensional frequency domain obtained from the output of 3, and is a frequency domain for detecting the spectrum spread of the Y signal for selecting the 3-field YC separation A.

Further, the correlation between the sample point of interest "◎" and the sample point "." in FIG. 4(b) is detected as follows. The two sample points are added by an adder 41, and a horizontal high frequency component is extracted through a band pass filter 44. The output of the bandpass filter 44 is inputted as an absolute value by the absolute value circuit 33 to the maximum value selection circuit 46,
In Figure 4(b), the sample point of interest “◎” and the sample point “・
” is detected.

The solid line portion in FIGS. 13(a) to (c) is the three-dimensional frequency domain obtained from the output of the bandpass filter 44, and is the frequency at which the spread of the spectrum of the Y signal is detected for selecting YC separation B within three fields. It is an area.

Further, the correlation between the sample point of interest "◎" and the sample point A "." in FIG. 4(b) is detected as follows. The two sample points are added by an adder 42, and a horizontal high frequency component is extracted through a band pass filter 45. The output of the bandpass filter 45 is inputted as an absolute value by the absolute value circuit 34 to the maximum value selection circuit 46,
In Figure 4(b), the sample point of interest “◎” and the sample point I “・
” is detected.

The solid line portion in FIGS. 14(a) to (c) is the three-dimensional frequency domain obtained from the output of the bandpass filter 45, and the spread of the spectrum of the Y signal for selecting the YC separation C within three fields is detected. It is in the frequency domain. The maximum value selection circuit 46 detects the maximum one (the one with the maximum correlation) among the three types of absolute value inputs and controls the signal selection circuit 37 .

[Effects of the Invention] As described above, according to the present invention, when the motion detection circuit detects a moving image, the 3-field YC separation circuit
Since the configuration is configured to locally detect the correlation between fields and adaptively select a plurality of interfield calculations including calculations between three fields, it is possible to detect the correlation between images in video processing using a motion adaptive YC separation filter. This makes it possible to perform optimal YC separation using this method, and has the effect of configuring a motion adaptive YC separation filter that performs YC separation with little deterioration in resolution even in moving images.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a motion adaptive YC separation filter according to an embodiment of the present invention, and FIG.
3 is a block diagram showing the detailed configuration of the intra-field YC separation circuit, FIG. 3 is a block diagram showing the detailed configuration of another embodiment of the 3-field YC separation circuit in FIG. 1, and FIG. In the dimensional time and space, the color subcarrier is 4 times as large as the digitized V signal array on the t-axis and y-axis. A plan view consisting of the y-axis and the y-axis, Figure 5 (a) is a diagram of the spectrum distribution of the V signal in a three-dimensional frequency space viewed from an oblique direction, and Figure 5 (b) is a diagram of the spectrum distribution in Figure 5 (a). A diagram of the spectral distribution viewed from the negative direction of the f-axis, Figure 5 (c)
is a diagram of the spectral distribution in FIG. 5(a) viewed from the positive direction of the μ axis, and FIG. 6(a) is a diagram of the spectral distribution in FIG.
Figure 6(b) is a diagram of the spectral distribution of the Y signal and C signal obtained by intra-field YC separation viewed from an oblique direction on a three-dimensional frequency space. The view seen from the negative direction, Figure 6(c), is the same as Figure 6(
Figure 7(a) is a three-dimensional diagram of the spectral distribution of the Y signal and C signal obtained by the second three-field YC separation according to the present invention. Diagram viewed from an oblique direction in frequency space, Figure 7 (
b) is a diagram of the spectral distribution in Figure 7(a) viewed from the negative direction of the f axis, and Figure 7(C) is a diagram of the spectral distribution in Figure 7(a) viewed from the positive direction of the μ axis. Figure 8(a) is a diagram of the spectral distribution of the Y signal and C signal obtained by the third three-field YC separation according to the present invention viewed from an oblique direction in a three-dimensional frequency space. b) is the eighth
FIG. 8(a) is a diagram of the spectral distribution viewed from the negative direction of the f-axis, and FIG. 8(c) is a diagram of the spectral distribution of FIG. 8(a) viewed from the positive direction of the μ-axis. 9 to 11 are diagrams showing the frequency domain of correlation detection in the embodiment of FIG. 2, and FIG.
Figure 9(b) is a diagram of the frequency domain of correlation detection for not selecting an intra-field YC separation filter viewed from an oblique direction on a three-dimensional frequency space. Figure 9 (C) is a diagram of the frequency domain in Figure 9 (a) viewed from the positive direction of the μ axis, Figure 10 (a) is the YC separation within the second three fields. Figure 10(b) is a diagram of the frequency domain of correlation detection for not selecting a filter viewed from an oblique direction on a three-dimensional frequency space, and Figure 10(b) is a diagram of the frequency domain of Figure 10(a) viewed from the negative direction of the f-axis. Fig. 10(c) is a diagram of the frequency region in Fig. 1O(a) viewed from the positive direction of the μ axis, Fig. 11(a)
Figure 11(b) is a diagram of the frequency domain of correlation detection for not selecting the third three-field YC separation filter viewed from an oblique direction on a three-dimensional frequency space, and Figure 11(b) is the frequency domain in Figure 11(a). Viewed from the negative direction of the f axis, 11th
FIG. 11(C) is a diagram of the frequency region in FIG. 11(a) viewed from the positive direction of the μ axis. 12 to 14 are diagrams showing the frequency domain of correlation detection in the embodiment of FIG. 3, and FIG.
Figure 12(b) is a diagram of the frequency domain of correlation detection for selecting the three-field YC separation filter viewed from an oblique direction on a three-dimensional frequency space. View from the negative direction, Figure 12(c)
is a diagram of the frequency domain in Figure 12 viewed from the positive direction of the μ axis, and Figure 13 (a) is a three-dimensional frequency space diagram of the frequency domain of correlation detection for selecting the second three-field YC separation filter. The above view from an oblique direction, Fig. 13(b)
is a diagram of the frequency region in FIG. 13(a) seen from the negative direction of the f axis, FIG. 13(c) is a diagram of the frequency region in FIG. 13(a) seen from the positive direction of the μ axis, Figure 14 (a
) is a diagram of the frequency domain of correlation detection for selecting the third three-field YC separation filter viewed from an oblique direction on a three-dimensional frequency space, and Figure 14 (b) is the frequency in Figure 14 (a). Diagram of the area viewed from the negative direction of the f-axis, No. 14
Figure (c) is a diagram of the frequency domain in Figure 14 (a) viewed from the positive direction of the μ axis, and Figure 15 is a diagram of the conventional motion adaptive YC.
A block diagram of the separation filter. FIG. 16 is a block diagram showing the detailed configuration of the Y signal motion detection circuit in the motion adaptive YC separation filter of FIG. 15. FIG. 17 is a block diagram showing the detailed configuration of the Y signal motion detection circuit in the motion adaptive YC separation filter of FIG. FIG. 18 is a block diagram showing the detailed configuration of the C signal motion detection circuit, FIG. 18 is a block diagram showing the detailed configuration of the interframe YC separation circuit in the motion adaptive YC separation filter of FIG. 15, and FIG.
20 is a block diagram showing a detailed configuration of the intra-field YC separation circuit in the motion adaptive YC separation filter shown in FIG.
The figure is a block diagram showing another example of the conventional C signal motion detection circuit. 5... Between frames, YC separation circuit, 6... Y signal motion detection circuit, 7... C signal motion detection circuit, 8... Combination circuit, 9... Y signal mixing circuit, 1o...・C signal mixing circuit 50...3 field YC separation circuit, 9o・
...Motion detection circuit. In addition, in the figures, 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, image movement is locally 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 When the interframe luminance signal color signal separation circuit that outputs the color signal and the motion detection circuit detect a moving image, the horizontal low frequency of the difference at the point where the phase of the color subcarrier is opposite between fields Correlations are locally detected based on the components, and based on the detection results, processing is performed to adaptively switch between a plurality of inter-field processes including calculations between three fields, and three-field intra-field luminance signals, chrominance signals, and separated luminance signals are output. , and a 3-field luminance signal chrominance signal separation circuit that outputs 3-field luminance signal chrominance signal separated color signals by subtracting the 3-field intra-luminance signal chrominance signal separated luminance signal from the original composite color television signal;
A luminance signal mixing circuit that mixes the inter-frame luminance signal, chrominance signal, and separated luminance signal and the three-field luminance signal, chrominance signal, and separated luminance signal based on the output of the motion detection circuit, and outputs a motion-adaptive luminance signal, chrominance signal, and separated luminance signal. and a color signal that mixes the inter-frame luminance signal, chrominance signal, and separated color signal based on the output of the motion detection circuit and the three-field luminance signal, chrominance signal, and separated color signal to output a motion-adaptive luminance signal, chrominance signal, and separated chrominance signal. A motion-adaptive luminance signal/chrominance signal separation filter characterized by comprising a mixing circuit. (2) When the motion detection circuit detects a moving image instead of the intra-field luminance signal color signal separation circuit, the horizontal low frequency component and phase of the difference at the point where the phase of the color subcarrier is the same between fields A process that locally detects the correlation by obtaining the horizontal high frequency component of the sum at the point where is the opposite, and adaptively switches between multiple inter-field processes, including calculations between three fields, based on the detection result. The 3-field luminance signal chrominance signal separation is performed, and the 3-field luminance signal chrominance signal separation is output, and the 3-field luminance signal chrominance signal separation is performed by subtracting the 3-field luminance signal chrominance signal separation luminance signal from the original composite color television signal. 2. The motion adaptive luminance signal/chrominance signal separation filter according to claim 1, wherein the filter is replaced with a three-field intra-field luminance signal/chrominance signal separation circuit that outputs a chrominance signal.