JPH03274886A - Motion adaptive type luminance signal/chrominance signal separating filter - Google Patents

Abstract

PURPOSE:To decrease the degradation of a picture quality by providing an in-frame YC separating circuit for detecting locally a correlation between fields, executing a processing for switching adaptively plural in-frame processings containing an inter-field operation and a band limit of a luminance signal by an in-field operation. CONSTITUTION:An output of a signal selecting circuit 29 is inputted to an input terminal of a one-line delaying circuit 31, a second input terminal of a subtracter 30 and a first input terminal of an adder 32 and a subtracter 33, respectively. An output of the one-line delaying circuit 31 is inputted to a second input terminal of the adder 32 and the subtracter 33, respectively. An output of the adder 32 is inputted to a first input terminal of an adder 35. An output of the subtracter 33 is inputted to an input terminal of an LPF 34. An output of an adder 36 is outputted from an output terminal 12 as an in-frame YC separating Y signal 112. Also, the output of the adder 36 is inputted to a second input terminal of a subtracter 37. An output of the subtracter 37 is outputted from an output terminal 13 as an in-frame YC separating C signal 113.

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. 12 is a block diagram showing an example of a conventional motion adaptive YC separation filter. In the figure, an NTSC V signal 101 is input to an input terminal 1, and is input to the input terminals of an intra-field YC separation circuit 4, an inter-frame YC separation circuit 5, a Y signal motion detection circuit 6, and a C signal motion detection circuit 7. each is given.

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 IO.

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 IO, 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 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 10 is sent out from the output terminal 3.

Next, the operation 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 41 as shown in FIG. 14, and a directly inputted signal ■. 101 is subtracted by a subtracter 42 to obtain a two-frame difference, which is passed through a band pass filter (hereinafter referred to as BPF) 43, its absolute value is determined by an absolute value circuit 44, and this absolute value is converted to a nonlinear A conversion circuit 45 converts the C signal into a signal 107 indicating the amount of movement, and outputs the signal 107 from an output terminal 49.

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=o, and if the image is determined to be a completely moving image, then k=o. 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.

For example, as shown in FIG. 15, the inter-frame YC separation circuit 5 separates a V signal 101 input from an input terminal 61 into a signal delayed by one frame in a one-frame delay circuit 64, and a V signal 101 input directly. are added by an adder 65 to obtain the l-frame sum, extract the YF signal 104, and send it to the output terminal 62.
At the same time, the subtracter 66 subtracts the YF signal 104 from the V signal 101 input from the input end 61 to extract the CF signal 105 and output it from the output end 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. 16, the V signal 101 inputted from the input terminal 71 is delayed by one line in the one line delay circuit 74, and the directly inputted ■signal 101 is added in the adder 75 to obtain the l line sum. The Yf signal 102 is extracted and outputted from the output terminal 72, and the subtracter 76 extracts the Yf signal 102 from the input terminal 72.
By subtracting the Yf signal 102 from the V signal 101 input from 1, the Cf signal 103 is extracted, and the output terminal 7
It is output from 3.

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 10B 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+N-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 the input terminal 11, and the color demodulation circuit 46 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 47, delayed by two frames by a two-frame delay circuit 41, and then divided into two frames by a subtracter 42. By subtracting the output of the delay circuit 41 and the output of the time division multiplexing circuit 47, a two-frame difference is obtained.

This two-frame difference is passed through an LPF 48 to remove the Y signal component, an absolute value circuit 44 takes the absolute value, and a nonlinear conversion circuit 45 performs nonlinear conversion to obtain the motion detection amount of the C signal.
07 can be sent out from the output end 49.

[Problems to be Solved by the Invention] The conventional motion adaptive YC separation filter is configured as follows. Based on the synthesized amount, the intra-field YC separation circuit 4 generates a Yf multiplied signal Cf signal and the inter-frame YC separation circuit 5
The YF multiplied signal and CF signal are mixed respectively.

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 Problems] The motion adaptive YC separation filter according to the present invention locally detects correlation between fields when a motion detection circuit detects a moving image, and performs interfield calculation based on the detection result. an intra-frame YC separation circuit that adaptively switches between a plurality of intra-frame processes including band limiting of luminance signals by intra-field calculations and outputs an intra-frame YC-separated Y signal and an intra-frame YC-separated C signal; It has been established.

[Operation] The intra-frame 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 intra-frame YC based on the magnitude of the correlation.
By selecting one of the C separation circuits, an intra-frame YC separated Y signal and an intra-frame YC separated C signal are output.

[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.

In FIG. 1, the intra-field YC separation circuit 4 in FIG. 12 is replaced with an intra-frame YC separation circuit 50, and the other portions have been described in the conventional example and will therefore be omitted.

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

In the figure, a V signal 101 is input to an input terminal 11. This V signal 101 is applied to two pixel delay circuits 14 and 2.
It is input to the input terminal of the 62-line delay circuit 15.

The signals delayed by two pixels by the two-pixel delay circuit 14 are input to the first input terminals of subtracters 19, 20, 21, 30, and 37, respectively.

V delayed by 262 lines by the 262 line delay circuit 15
The signals are input to the input terminals of the l-line delay circuit 16 and the 4-pixel delay circuit 17, and to the second input terminal of the subtracter 19, respectively.

The V signal delayed by one line by the one line delay circuit 16 is 2
It is input to the input terminal of the pixel delay circuit 18. The (2) signal delayed by four pixels by the four-pixel delay circuit 17 is input to the second input terminal of the subtracter 20.

The (2) signal delayed by two pixels by the two-pixel delay circuit 18 is input to the second input terminal of the subtracter 21 .

The output signal of the subtracter 19 is input to the first input terminal of the signal selection circuit 29 and the input terminal of the LPF 22 . Subtractor 20
The output signal of LP is connected to the second input terminal of the signal selection circuit 29 and
It is input to the input terminal of F23. The output signal of the subtracter 21 is input to the third input terminal of the signal selection circuit 29 and the input terminal of the LPF 24.

, the output of the LPF 22 is the input terminal of the absolute value circuit 25, the LPF
The output of LPF 23 is input to the input terminal of absolute value circuit 26, and the output of LPF 24 is input to the input terminal of absolute value circuit 27.

The output of the absolute value circuit 25 is connected to the first input terminal of the minimum value selection circuit 28, the output of the absolute value circuit 26 is connected to the second input terminal of the minimum value selection circuit 28, and the output of the absolute value circuit 27 is connected to the minimum value selection circuit 28. They are respectively input to the third input terminals of the circuit 28.

The output of the minimum value selection circuit 28 is input to the fourth input terminal of the signal selection circuit 29, thereby selectively controlling the first to third inputs.

The output of the signal selection circuit 29 is sent to an input terminal of a one-line delay circuit 31, a second input terminal of a subtracter 30, and an adder 32. The signals are respectively input to the first input terminals of the subtracter 33. (2) The output of the line delay circuit 31 is input to the second input terminals of an adder 32 and a subtracter 33, respectively. The output of adder 32 is input to a first input terminal of adder 35. The output of the subtracter 33 is input to the input terminal of the LPF 34. The output of the LPF 34 is input to the second input terminal of the adder 35. The output of the subtracter 30 is input to the first input terminal of the adder 36,
The output of 5 is input to the second input terminal of adder 36.

The output of the adder 36 is outputted from the output terminal 12 as an intra-frame YC separated Y signal 112. Further, the output of the adder 36 is input to the second input terminal of the subtracter 37. Subtractor 3
The output of 7 is output from the output terminal 13 as an intra-frame YC separated C signal 113.

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 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 color subcarrier frequency fsc (= 3.58M
The color subcarriers when digitized at four times the frequency (Hz) indicate sample points in which the color subcarriers are in the same phase.

Now, if we represent the sample point ``◎'' in the same field, the color subcarrier phase differs by 180 degrees between the two sample points and the four points a, b, c, and d above and below one line in the same field, n field. .

Therefore, a line comb filter using a digital circuit or 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 constructed.

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 the ■ line or the 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, the frequency axes corresponding to the X-axis, y-axis, and t-axis are the μ axis, which is the horizontal frequency axis, and the ν axis, which is the vertical frequency axis.
Considering the f-axis, which is the axis and the time-frequency axis, it is possible to consider a three-dimensional frequency space that can be composed of the μ-axis, v-axis, and f-axis, which are orthogonal to each other.

FIG. 5 shows a projection diagram of the three-dimensional frequency space. FIG. 5(a) is a diagram of the three-dimensional frequency space viewed from an oblique direction, and FIG. FIG. 5(c) is a diagram of the 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 quadrature two-phase modulation of the ■ 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.

In FIG. 4(b), in the n-1 field, there are two sample points A, B, and A, which are located 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. 4(b). This is followed by a 1-line delay circuit 31. Adder 32.35, subtracter 33, LPF
The C signal can be removed by passing it through a two-dimensional comb filter composed of 34. The Y signal is obtained by adding this result to the low frequency component in the three-dimensional frequency space that does not include the C signal, which is the output of the subtracter 30. Further, the C signal is obtained by subtracting the Y signal from the V signal. This is referred to as inter-field YC separation A.

Figures 6 (a) to (c), like Figures 5 (a) to (c), represent a three-dimensional frequency space, and the presence of the Y signal and C signal obtained by YC separation A between fields and fields. shows the frequency space.

Second, high-frequency components 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 "." A in FIG. 4(b). Add to this the above 2
The C signal can be removed by passing it through a dimensional comb filter.

Thereafter, the Y signal and C signal are obtained by the same processing as above. This is referred to as inter-field YC separation B.

Figures 7(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. 7(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. 4(b). Add to this the above 2
The C signal can be removed by passing it through a dimensional comb filter.

Thereafter, the Y signal and C signal are obtained by the same processing as above. This is referred to as inter-field YC separation C.

Figures 8(a) to (c) also have inter-field YC separation C.
It shows the frequency space in which the Y signal and C signal obtained by the above exist. Looking at Figures 8(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 7, 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, the sample point of interest ``◎'', the sample point ``・'' A,
It is necessary to detect the correlation between

Since it is the V signal that is digitized, in order to detect the correlation, it is sufficient to pass each difference through an LPF, detect the correlation of the low frequency components of the Y signal, and use it as a control signal.

Next, the operation of the intra-frame YC separation circuit having the configuration 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 2 pixels in the 2-pixel delay circuit 14, and 262
The line delay circuit 15 delays the signal by 262 lines.

The V signal delayed by 2 pixels in the 2-pixel delay circuit 14 and 262
By subtracting the output of the line delay circuit 15 using a subtracter 19, an inter-field difference for inter-field YC separation C is obtained.

By subtracting the V signal delayed by two pixels in the two-pixel delay circuit 14 and the output of the four-pixel delay circuit 17 in a subtracter 20, 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 14 and the output of the two-pixel delay circuit 18 by the subtracter 21, 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 29, and selected by the output of the minimum value selection circuit 28, which will be described later.

The inter-field difference which is the output of the subtracter 19 is also 2,
The signal is passed through an LPF 22 with a passband of 1 MHz or less, converted into an absolute value by an absolute value circuit 25, and inputted to a minimum value selection circuit 28 to calculate the correlation between the point of interest and the sample point in FIG. 4(b). To detect.

The inter-field difference which is the output of the subtracter 20 is also 2,
It passes through an LPF 23 with a passband of 1 MHz or less, is converted into an absolute value by an absolute value circuit 26, is inputted to a minimum value selection circuit 28, and is used to calculate the correlation between the point of interest and sample point A in FIG. 4(b). Detect.

The inter-field difference which is the output of the subtractor 21 is also 2,
It passes through an LPF 24 whose passband is 1 MHz or less, is converted into an absolute value by an absolute value circuit 27, is input to a minimum value selection circuit 28, and is used to calculate the correlation between the table of interest and sample point A in FIG. 4(b). Detect.

The minimum value selection circuit 28 selects the minimum one (the one with the maximum correlation detection amount) among the above three types of absolute value outputs, and controls the signal selection circuit 29.

That is, the signal selection circuit 29 selects the output of the subtracter 19 when the output of the absolute value circuit 25 is the minimum, the output of the subtracter 20 when the output of the absolute value circuit 26 is the minimum, and the output of the subtracter 20 as the output of the absolute value circuit 27.
If the output of the subtracter 21 is the minimum, the output of the subtracter 21 is selected.

Further, the output of the signal selection circuit 29 is subtracted from the V signal by a subtracter 30 to obtain a three-dimensional frequency spatial low frequency component in the direction in which the correlation is detected.

On the other hand, since the output of the signal selection circuit 29 is a three-dimensional frequency high-frequency component in the direction in which the correlation is detected, a two-dimensional comb consisting of a one-line delay circuit 31, an adder 32, 35, a subtracter 33, and an LPF 34 is used. By passing through a shape filter,
C signal can be removed. By adding the outputs of the subtracter 30 and the adder 35 in an adder 36, an intra-frame YC separated Y signal 112 can be obtained.

The subtracter 37 selects V, which is the output of the two-pixel delay circuit 14.
By subtracting the intraframe YC separated Y signal 112 from the signal, an intraframe YC separated Y signal 113 can be obtained.

Note that although in FIG. 2, an operation including the 1-line delay circuit 31 is used to remove the C signal, the same effect can be obtained by performing an operation using a plurality of 1-line delay circuits.

FIG. 3 shows YC in the frame in FIG. 1, which is this invention.
FIG. 6 is a detailed block diagram of another embodiment of separation;

In FIG. 3, the only difference from FIG. 2 is the method of detecting correlation between fields. Here, as a method of detecting the correlation of the V signal, a method of detecting the direction in which the spectrum of the Y signal spreads in a three-dimensional frequency space is used.

Y for selecting and controlling three types of inter-field YC separation
The frequency range in which the spread of the signal spectrum is detected is illustrated by solid lines in FIGS. 9, 10, and 11, respectively.

FIG. 9 shows the frequency domain for detecting the spectrum spread of the Y signal for selecting the interfield YC separation A.

This area can be detected by passing the LPF through the difference between the sample point of interest "◎" in FIG. 4(b) and the sample point rOJ located one line below the sample point "."A.

Figure 10 shows YC separation B for selecting interfield YC separation B.
This is the frequency domain in which the spread of the signal spectrum is detected.

This area can be detected by passing the BPF through the sum of the sample point of interest "◎" and the sample point "." A in FIG. 4(b).

Figure 11 shows YC separation C between fields.
This is the frequency domain in which the spread of the signal spectrum is detected.

This area can be detected by passing the BPF through the sum of the sample points of interest "◎" and the sample points "." in FIG. 4(b).

Next, of the intra-frame YC separation circuit having the configuration shown in FIG. 3, only the inter-field correlation detection circuit that is different from that shown in FIG. 2 will be described. In FIG. 3, the same parts as in FIG. 2 are given the same numbers.

Output of 262-line delay circuit 15 and 2-pixel delay circuit 14
The outputs of are added by adder 83, and the result is 2.1MH
It passes through a BPF 86 whose passband is z or more, is converted into an absolute value by an absolute value circuit 89, is input to a maximum value selection circuit 92, and is used to calculate the correlation between the point of interest and the sample point in FIG. 4(b). To detect.

The output of the 262-line delay circuit 15 is sent to the 2-pixel delay circuit 81.
．． 82 and is delayed by 4 pixels. The output of the 2-pixel delay circuit 82 and the output of the 2-pixel delay circuit 14 are added by an adder 84,
The result is a BPF of 87 with a passband of 2.1MHz or higher.
The signal is then converted into an absolute value by an absolute value circuit 90, and is input to a maximum value selection circuit 92 to detect the correlation between the point of interest and sample point A in FIG. 4(b).

The output of the 2-pixel delay circuit 81 and the output of the 2-pixel delay circuit 14 are subtracted by a subtracter 85, and the result is passed through an LPF 88 whose passband is 2°1 MHz or less, and then input to an absolute value circuit 9.
It is converted into an absolute value at 1, inputted to the maximum value selection circuit 92,
The correlation between the point of interest and sample point A in FIG. 4(b) is detected.

The maximum value selection circuit 92 selects the maximum one (the one with the maximum correlation detection amount) among the above three types of absolute value outputs, and controls the signal selection circuit 29.

[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 the correlation between fields and performs inter-field and intra-field calculations. 3 including band limit of luminance signal
Since the configuration is configured to perform YC separation within different types of frames, optimal YC separation can be performed using image correlation in video processing using a motion adaptive YC separation filter, and YC separation with little resolution degradation is possible even in videos. This has the effect of configuring a motion adaptive YC separation filter that performs separation.

[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, FIG. 2 is a block diagram showing a detailed configuration of the intra-frame YC separation circuit in FIG. 1,
FIG. 3 is a block diagram showing a detailed configuration of another embodiment of the intra-frame YC separation circuit in FIG. 1, and FIG. 4th plan view configuring the V signal arrangement on the t-axis and y-axis
Figure (b) is a plan view showing the arrangement of the ■ signals in Figure 4 (a) on the Figure 5(b) is a diagram of the spectral distribution in Figure 5(a) viewed from the negative direction of the f axis, and Figure 5(c) is a diagram of the spectral distribution in Figure 5(a) viewed from the negative direction of the f axis. Figure 6(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, viewed from an oblique direction in three-dimensional frequency space. Figure, Figure 6 (
b) is a diagram of the spectral distribution in FIG. 6(a) viewed from the negative direction of the f axis, FIG. 6(c) is a diagram of the same spectral distribution as seen from the positive direction of the μ axis, and FIG. a) is a diagram of the spectral distribution of the Y signal and C signal obtained by the second interfield YC separation according to the present invention viewed from an oblique direction on a three-dimensional frequency space, and FIG. Fig. 7(c) is a diagram of the spectral distribution in a) viewed from the negative direction of the f axis.
) is a diagram of the spectral distribution in FIG. 7(a) viewed from the positive direction of the μ axis, and FIG. 8(a) is a diagram of the Y signal and C signal obtained by the third interfield YC separation according to the present invention. Figure 8(b) is a diagram of the spectral distribution viewed from an oblique direction on a three-dimensional frequency space, and Figure 8(c) is a diagram of the spectral distribution in Figure 8(a) viewed from the negative direction of the f-axis. is shown in Figure 8 (
Figures 9 to 11 are diagrams of the spectral distribution in a) viewed from the positive direction of the μ axis, and Figures 9 to 11 are 3 in other embodiments of Figure 3.
FIG. 9 is a diagram showing the frequency domain of different types of correlation detection;
a) is a diagram of the frequency domain of correlation detection for selecting the first inter-field YC separation filter viewed from an oblique direction on a three-dimensional frequency space, and FIG. 9(b) is a diagram of the frequency region in FIG. 9(a). A diagram of the region viewed from the positive direction of the μ axis, Figure 9 (c
) is a diagram of the frequency domain seen from the positive direction of the μ axis, the first
Figure 0(a) is a diagram of the frequency domain of correlation detection for selecting the second interfield YC separation filter viewed from an oblique direction on a three-dimensional frequency space, and Figure 10(b) is a diagram of the frequency domain of correlation detection for selecting the second interfield YC separation filter, and Figure 10(b) is a diagram of the frequency domain of correlation detection for selecting the second interfield YC separation filter.
A diagram of the frequency domain in a) viewed from the negative direction of the f axis,
Figure 10 (c) is a diagram of the same frequency domain as seen from the positive direction of the μ axis, and Figure 11 (a) is a three-dimensional diagram of the frequency domain of correlation detection for selecting the third interfield YC separation filter. Diagram viewed from an oblique direction in frequency space, Figure 11(b)
is a diagram of the frequency domain in FIG. 11(a) viewed from the negative direction of the f axis, FIG. 11(c) is a diagram of the frequency domain in FIG. 11(a) viewed from the positive direction of the μ axis, Figure 12 is a block diagram of a conventional motion adaptive YC separation filter;
The figure shows Y in the motion adaptive YC separation filter in Figure 12.
Block diagram showing the detailed configuration of the signal motion detection circuit, 1st
Fig. 4 is a block diagram showing the detailed configuration of the C signal motion detection circuit in the motion adaptive YC separation filter shown in Fig. 12, and Fig. 15 shows details of the interframe YC separation circuit in the motion adaptive YC separation filter shown in Fig. 12. 16 is a block diagram showing the detailed structure of the intra-field YC separation circuit in the motion adaptive YC separation filter of FIG. 12, and FIG. 17 is a block diagram showing the detailed structure of the conventional C signal motion detection circuit. FIG. 2 is a block diagram illustrating an example. 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 each figure, 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, 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 detected locally based on the components, and based on the detection results, processing is performed to adaptively switch between multiple intra-frame processes, including band limiting of luminance signals by inter-field calculations and intra-field calculations, to calculate the intra-frame luminance. Outputs signal color signal separated luminance signal,
Furthermore, an intra-frame luminance signal/chrominance signal separation circuit that outputs an intra-frame luminance signal/color signal separated color signal by subtracting the intra-frame luminance signal/color 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 separated luminance signal and the intra-frame luminance signal chrominance signal separated luminance signal based on the output to output a motion-adaptive luminance signal chrominance signal separated luminance signal; and the motion detection circuit. and 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 separated color signal based on the output of the chrominance signal and outputs a motion-adaptive luminance signal, chrominance signal, and separated chrominance signal. A motion-adaptive luminance signal and chrominance signal separation filter featuring: (2) When the motion detection circuit detects a moving image instead of the intra-frame luminance signal color signal separation circuit described above, the horizontal low frequency wavenumber component of the difference at the point where the phase of the color subcarrier is the same between fields Then, the correlation is locally detected by obtaining the horizontal high frequency components of the sums at points where the phases are opposite, and based on the detection results, the band limitation of the luminance signal by inter-field calculation and intra-field calculation is performed. The process adaptively switches between multiple intra-frame processes, and outputs an intra-frame luminance signal and chrominance signal separated luminance signal, and also converts the intra-frame luminance signal and chrominance signal separated luminance signal from the original composite color television signal. Claim 1, characterized in that the apparatus is replaced with an intra-frame luminance signal/color signal separation circuit which outputs an intra-frame luminance signal/chrominance signal separated color signal by subtracting the intra-frame luminance signal/chrominance signal.
Motion adaptive luminance signal chrominance signal separation filter as described in .