JPH06105332A - Separation system of brightness signal and color signal - Google Patents

Abstract

PURPOSE: To improve the line correlative relation of chrominance signal by synchronizing a composite video signal with the output of prescribed filter through a delayed and defining the output difference of delayer and filter as a luminance signal. CONSTITUTION: A line comb-line filter 20 out finds a line difference signal between lines from the composite video signal and outputs one signal, having satisfactory correlative relation as a line chrominance signal. Further, a filter 21 outputs the chrominance signal from the composite video signal and a line correlation detector 22 detects the correlation between lines and sends a signal to the filter 20. Then, a chrominance signal level detector 23 detects the output level of filter 21, and a filter 25 inputs the signals of filters 20 and 21. Further, the filter 25 is controlled by the output of detectors 22 and 23 and filters a switch SW 21 for selectively outputting one of input signals. Next, the composite video signal is synchronized with the output of a filter 25 by a delayer 24 and the output difference of delayer 24, and the filter 25 is outputted as the final luminance signal by a subtracter 26. Thus, a chrominance signal having satisfactory line correlative relation is provided.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the NTSC system, PAL
The present invention relates to a system that separates a luminance signal and a chrominance signal from a composite video signal of TV broadcasting such as the H.264 or SECAM system, and particularly relates to a high-resolution HDTV (High Definition Television set), ED (Enhanced Definition, Enhanced Definition). ) TV and HDVCR (High Definition Video Cassette Recorder, High
The present invention relates to a luminance signal and chrominance signal separation system suitable for obtaining a higher quality image from a high definition system such as a Definition Video Cassette Recorder).

[0002]

2. Description of the Prior Art FIG. 1 is a block diagram showing a conventional luminance signal and chrominance signal separation system using frame and line comb filters, and FIG. 2 is a conventional luminance signal and chrominance signal separation system using line comb filters. It is a block diagram which shows a color signal separation system. Here, the frame means one screen of TV broadcasting.

In the case of TV broadcasting (for example, NTSC system),
One frame is composed of 525 lines, and one screen (that is, one frame) is transmitted from the broadcasting station every 1/30 seconds. In one frame, the odd-numbered and even-numbered 252.5 lines are skipped every 1/60 second and are transmitted from the broadcasting station by the scanning method. Therefore, one frame consists of two fields.

In the NTSC system, one line is 15.
It is composed of a unit of 75 KHz (64.5 μs). As described above, the one-frame signal used below is 525.
A line-delayed video signal (that is, a video after 2 fields or 1/30 second) is a signal, and the frame difference signal is a frame signal one frame before the current frame signal or a frame signal after one frame. It means a signal obtained by subtracting the frame signal.

Since the component of the luminance signal is removed from the frame difference signal, only the component of the color signal is used. The reason will be described later.

The comb filter used in FIGS. 1 and 2 will be described with reference to FIGS. 3 (A) and 3 (B). Figure 3
FIG. 3A shows an arrangement of a luminance signal and a chrominance signal between respective lines in an NTSC TV broadcasting signal as a frequency spectrum, and FIG. 3B shows a luminance signal and a color between frames in an NTSC TV broadcasting signal. The arrangement with a signal is shown as a frequency spectrum. The NTSC TV broadcast signal is a mixture of a color signal and a luminance signal, as shown in FIGS. 3A and 3B. The luminance signal and the color signal are mixed with each other. Are alternately arranged on the frequency spectrum.

The comb filter is used to separate the luminance signal and the chrominance signal from the composite video signal.

In the NTSC TV broadcast signal, the phase of the chrominance signal is inverted by 180 ° for each line and is also inverted by 180 ° for each frame (for each signal after 525 lines). . Therefore, if the composite video signals of two lines are added, the color signal has a phase of 18
Since it is different by 0 °, it is erased and only the pure luminance signal remains, and conversely, when the composite video signal of two lines is subtracted, the luminance signal is erased and only the color signal component remains. Therefore, by using this principle, the luminance signal and the chrominance signal can be separated from the composite video signal, and the line comb filter and the frame comb filter in FIGS. 1 and 2 use this principle.

First, the operation of the configuration shown in FIG. 1 will be described.

Composite video signa (CV)
l) is input to the frame comb filter (1),
The frame comb filter (1) separates the luminance signal and the chrominance signal from the composite video signal (CV) in frame units,
The separated frame color signal (FC) is supplied to the calculator (4). At the same time, the composite video signal (CV) is supplied to the comb filter (2), and the line comb filter (2) separates the luminance signal and the chrominance signal on a line-by-line basis, and then separates the separated line color signal (LC). Is supplied to the arithmetic unit (5).

On the other hand, the frame difference signal (FD) provided from the frame comb filter (1) is used as a moving level detector (moving level detector) to detect the degree of motion of the video signal.
el detector) (3), the motion level detector (3) obtains a motion coefficient (K) corresponding to the degree of motion of the video signal using the frame difference signal (FD),
It is supplied to the computing units (4) and (5). Here, the motion coefficient (K) is a value between 0 and 1 (0 ≦ K ≦ 1).
That is, the closer the motion coefficient (K) is to 1, the greater the degree (level) of motion of the video signal.

The arithmetic unit (4) subtracts the motion coefficient (K) from 1 to the input frame color signal (FC) (1- (1)).
K) is multiplied and output, and the calculator (5) multiplies the input line color signal (LC) by the motion coefficient (K) and outputs. The output signals of the arithmetic units (4) and (5) are added to each other by the adder (6), and the adder (6) outputs the added color signal to the band pass filter (8).

In the NTSC TV broadcast signal, the color signal has a center frequency of 3.5 when viewed on the frequency spectrum.
Since it is located in a band of ± 0.5 MHz centering on 8 MHz, the signal output through the band pass filter (8) becomes the final color signal (C) having a desired band of about 3 MHz to 4.2 MHz.

This color signal (C) is output as the final color signal and is supplied to the subtractor (9).

On the other hand, the composite video signal (CV) has a frame comb filter (1) and a line comb filter (2).
It is also supplied to the delay device (7), where it is output after being delayed for a predetermined time so as to be synchronized with the color signal (C) output through the band pass filter (8). The subtractor (9) outputs a signal obtained by subtracting the color signal (C) from the composite video signal (CV) delayed for a predetermined time as the final luminance signal (Y).

The operation of the configuration of FIG. 2 will be described.

When the composite video signal (CV) is input to the line comb filter (11), the line comb filter (11) extracts a color signal from the composite video signal (CV) on a line-by-line basis, and then the line color is extracted. The signal (LC) is output to the bandpass filter (12). Band pass filter (12)
Is for extracting only the color signal component from the input line color signal (LC), and extracts and outputs only the color signal (C) having a ± 0.5 MHz band centered on the center frequency (fsc).

At the same time, the line color output (LC) is also supplied to the low pass filter (13), and the low pass filter (1)
3) removes a color subcarrier from the input line color signal (LC). Therefore, the low pass filter (13) outputs only the residual luminance component (ΔY) that does not include the color signal.

As shown in FIG. 3 (A), since the color signal and the luminance signal overlap, the line comb filter (1
Even if the line color signal (LC) is separated by 1), the residual luminance component (ΔY) may be included. This residual luminance component (ΔY) increases more in the case of a moving video signal. This residual luminance component (ΔY) is calculated by the absolute value calculator (1
After being converted to an absolute value by 4), it is applied to the non-inverting input terminal (+) of the comparator (CP ₁ ). Comparator (CP ₁ )
Compares the absolute value with a set threshold value (Vth ₁ ) value applied to the inverting input terminal (−), and outputs the resulting value as a switching control signal for the switch (SW ₁ ).

On the other hand, the composite video signal (CV) is delayed by the delay device (1
5), and the delay device (15) delays the composite video signal (CV) by a predetermined time so that the output signal of the band pass filter (12) is synchronized with the time when it is supplied to the subtractor (16). Then, it is supplied to the subtractor (16). Subtractor (1
6) supplies the luminance signal obtained by subtracting the color signal (C) from the composite video signal (CV) to the delay device (17) and the band trap filter (18). The output side of the delay device (17) is connected to the input terminal (a) on one side of the switch (SW ₁ ) and the output side of the band trap filter (18) is connected to the input terminal on the other side, and the switch (SW ₁ ) is connected.
Is controlled by the switch control signal output from the comparator (CP ₁ ) to select and output one of the two input signals. That is, when the output signal of the comparator (CP ₁ ) is a high level signal, there is dot interference. Therefore, at this time, the switch (SW ₁ ) selects the output signal of the band trap filter (18), On the contrary, the comparator (C
P ₁ ) If the output signal is a low level signal, select the output signal of the delay device (17).

The signal thus selected is output as the final luminance signal (Y).

A conventional luminance signal and chrominance signal separation system using the above-described line and frame comb filters is an IDTV receiver (Kawaikiyoyuki, Toshiba Corporation Consumer Product Engineering Laboratory, Yokohama, Japan, etc., IEEE Transactions on C
onsumer Electronics, Vol. CEO33 No. 3, August 198
7).

[0023]

However, such a conventional technique has the following problems.

1. Figure 2 using a line comb filter
According to the configuration of (1), the current line signal output through the comb filter, the signal before 1 line and the signal after 1 line are directly filtered by the band pass filter and the low pass filter. A crosstalk component may be generated depending on such separation.
This causes dot interference, which adversely affects image quality.

2. According to the configuration of FIG. 1 using the line comb filter and the frame comb filter, the motion level detector (3) has a signal obtained by low-pass filtering the frame difference signal (FD) (that is, the residual luminance signal component) and the video signal. Since the degree of movement of the color signal is determined, the movement of the color signal and the movement in the high frequency signal component cannot be detected.

It is an object of the present invention to provide a luminance signal and chrominance signal separation system that solves the above disadvantages.

Another object of the present invention is that, based on the line correlation, if the line correlation is good, the line difference signal is used to separate the luminance signal and the color signal, and the line correlation is bad. An object of the present invention is to provide a luminance signal / color signal separation system for separating a luminance signal and a color signal using a color signal extracted through a general filtering means.

Still another object of the present invention is to combine a frame difference signal and a color signal extracted through general filtering means when the line correlation is bad based on the motion and line correlation of the composite video signal. Is used to separate the luminance signal and the chrominance signal, and if the line correlation is good,
It is an object of the present invention to provide a luminance signal / color signal separation system that separates a luminance signal and a color signal using a combination of a frame difference signal and a line difference signal.

[0029]

In order to achieve the above object, according to the present invention, the line comb filter means obtains a plurality of line difference signals between lines from the input composite video signal, and by the control signal. Of the plurality of line difference signals, one having a good line correlation is output as a line color signal.
The first filtering means extracts a color signal from the composite video signal and outputs it.

The line correlation detecting means detects the correlation between the lines using the plurality of line difference signals, and supplies the detected signal to the line comb filter means as a control signal.

The color signal detecting means detects the magnitude (level) of the color signal output from the first filtering means. The switching means inputs the color signal from the first filtering means and the line color signal from the line comb filter means, and uses the detection signal of the line correlation detection means and the output signal of the color signal detection means as control signals. Two
One of the two input signals is selected and output.

The second filtering means filters the output signal of the switching means and outputs a color signal component.

The third filtering means filters the output signal of the switching means and outputs it as the final color signal. The delay means delays the composite video signal for a predetermined time so as to synchronize with the generation of the output signal of the second filtering means.

The subtracting means outputs a second signal from the output signal of the delay means.
The output signal of the filtering means is subtracted and output as the final luminance signal.

In order to achieve the above object, according to the present invention, the frame-comb filter means obtains a frame difference signal between adjacent frames from the input composite video signal, and determines the frame difference signal as a frame color. Output as a signal.

The line comb filter means obtains a plurality of line difference signals between the lines from the composite video signal, and outputs one of the plurality of line difference signals having a good line correlation as a line color signal by an external control signal. To do. The first filtering means extracts a color signal from the composite video signal and outputs it.

The line correlation detecting means detects the correlation between the lines using the plurality of line difference signals provided from the line comb filter means, and supplies the detected signal to the line comb filter means as a control signal. .

The color signal detecting means detects the level of the color signal output from the first filtering means. The switching means simultaneously inputs the color signal output from the first filtering means and the line color signal output from the line comb filter means, and outputs the output signals of the line correlation detecting means and the color signal detecting means as control signals. , And outputs one of the signals.

The motion level detecting means detects the degree of motion of the video signal based on the frame difference signal provided from the frame comb filter means. The motion signal generating means generates a predetermined motion coefficient by the output signal of the line correlation detecting means and the output signal of the motion level detecting means.

The first calculation means calculates and outputs the output signal of the switching means and the motion coefficient, and the second calculation means outputs the motion coefficient from the output signal of the frame comb filter means and the set reference value. Is calculated and output.

The adding means adds the output signals of the first calculating means and the second calculating means, and the second filtering means filters the output signal of the adding means to output only the color signal component, and the third filtering means. Outputs the final color signal by filtering the output signal of the adding means.

The delay means delays and outputs the composite video signal so as to be synchronized with the generation of the output signal of the second filtering means, and the subtracting means outputs the composite video signal from the output signal of the delay means by the second signal.
The output signal of the filtering means is subtracted and the resulting value is output as the final luminance signal.

[0043]

Embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 4 is a block diagram showing a luminance signal and chrominance signal separation system using a line comb filter according to the first embodiment of the present invention.

As shown in this drawing, a plurality of line difference signals are detected from an input composite video signal (CV), and one line difference signal having a good line correlation is detected by an external control signal to obtain a line color signal (LC). And output as. A band-pass filter (21) for inputting a composite video signal (CV) together with a line comb filter (20) and a line comb filter (20) and extracting a color signal (center frequency fsc ± 0.5 MHz) from this. , A plurality of line difference signals (L
D) is used to determine the line correlation and a signal corresponding thereto is output to the line comb filter (20) as an external control signal. A line correlation detector (22) and a color output from the band pass filter (21). A color signal level detector (23) that outputs a signal corresponding to the signal level, an output signal of the line comb filter (20) to one input terminal (d), and an output signal of the band pass filter (21). To the input terminal (e) on the other side, and the line correlation detector (2
2) and the output signal of the color signal level detector (23) as a switching control signal, a switch (SW ₂₁ ) for selectively outputting one of the two input signals, and a switch (S
W ₂₁ ), the first filter (25) for extracting the color signal by band-pass filtering the output signal, and the line comb filter (20) together with the composite video signal (C
V) is inputted and delayed by a predetermined time so as to be synchronized with the generation of the output signal of the first filter (25), and the delayed signal is outputted from the output signal of the delay device (24).
A subtractor (2) for subtracting the output signal of the filter (25) and outputting the resulting value as the final luminance signal (Y)
6), and a second filter (27) for band-pass filtering the output signal of the switch (SW ₂₁ ) and outputting the filtered value as the final color signal (C).

FIG. 5 shows an embodiment of the line comb filter (20) and the line correlation detector (22) in FIG. In FIG. 5, the line comb filter (2
0) are two line delays (51) (52) (for example, two line memories are used), two subtractors (53) (54), one adder (55) and It is composed of one multiplexer (60).

The line correlation detector (22) includes two low pass filters (56) and (58), two absolute value calculators (57) and (59), and a threshold value (Vth ₂ ) set for each. , Vth ₃ ) with two comparators (CP
51) (CP52).

In this embodiment, the line comb filter (2
0) is composed of two subtractors, a line delay device and one adder, but it is composed of more subtractors, line delay devices and adders in order to obtain more line difference signals. You can also do it. Further, the line correlation detector can also be composed of more low pass filters, absolute value calculators and comparators.

FIG. 6 is a block diagram showing an embodiment of the color signal level detector (23) in FIG. 4, which is an absolute value calculator (23A) and a threshold value (Vth ₄ ) set at one terminal. And a comparator (23B) having The function of each element in FIG. 5 and FIG. 6 will be explained by the operation described below.

FIG. 7 is a block diagram showing a luminance signal and chrominance signal separating system using a line comb filter and a frame comb filter in a second embodiment of the present invention. In FIG. 7, a frame difference signal (FD) between adjacent frames is obtained from the input composite video signal (CV),
A frame comb filter (31) that outputs the frame difference signal as a frame color signal (FC) and a plurality of line difference signals (LD) from the input composite video signal are obtained.
A line comb filter (32) that selectively outputs one line difference signal having a good line correlation by an external control signal as a line color signal (LC), and extracts only color signal components from the input composite video signal (CV) A plurality of line difference signals (LD) are supplied from the band-pass filter (33) for outputting as a line output and the line comb filter (32) to determine the line correlation, and a signal corresponding to the result is output to the line. A line correlation detector (34) which outputs a control signal to a comb filter (32) and a frame difference signal (FD) supplied from the frame comb filter (31) are used to generate a video signal using the frame difference signal. A motion level detector (35) for detecting the degree of motion (level) and the level of the color signal output through the band pass filter (33) are detected, and the level is detected. 0 according to the motion level of the color signal level detector (36) that outputs a corresponding signal, the line correlation signal output through the line correlation detector (34) and the video signal output through the motion level detector (35). A motion signal generator (39) for generating a motion coefficient (K) having a value between 0 and 1 (0 ≦ K ≦ 1) and an output signal of the line comb filter (32) are input to one input terminal (g). The output signal of the band-pass filter (33) is input to the input terminal (h) at the other end, and is controlled by the output signals of the line correlation detector (34) and the color signal level detector (36). The switch (SW ₃₁ ) that selects and outputs one of the two selected signals and the switch (S
W ₃₁ ) output signal and the motion signal (K) value output from the motion signal generator (39) are multiplied and output (38), and the frame comb filter (31) output signal (FC) And the value obtained by subtracting the motion coefficient (k) from 1 (I
An arithmetic unit (37) for multiplying and outputting -K), an adder (40) for adding the output signals of the arithmetic unit (37) and the arithmetic unit (38), and an output signal of the adder (40) And a second filter (41) for outputting the final color signal (C) by band-pass filtering the output signal of the adder (40). 44) and a composite video signal (CV), and a delay device (42) for delaying for a predetermined time so as to be synchronized with the generation of the output signal of the first filter (41).
And a composite video signal (C
V) and a subtracter (43) for subtracting the component of the color signal output from the first filter (41) and outputting the final luminance signal (Y).

In FIG. 4 and FIG. 7, when the system implements the band compression function, the band pass filters (21) (33) and the first filter (25) having the band filtering function.
(41) can be replaced with a high-pass filter having a high-pass filtering function.

The line comb filter (32), the line correlation detector (34) and the color signal level detector (3)
The configuration example of 6) is the same as that of the first embodiment shown in FIGS. 5 and 6, and the description thereof is omitted.

Here, the band compression is called band compression when it is necessary to compress a composite video signal having a higher frequency as a signal in a low frequency band. For example, it is called band compression that the signal having a 10-mega bandwidth is not damaged and has a 5-mega bandwidth, and conversely, the compression of the compressed signal to the original band signal is called band expansion.

FIG. 8 is a block diagram showing the detailed structure of the motion level detector (35) and the motion signal generator (39) in FIG. The motion level detector (35) comprises a low pass filter (35A) and an absolute value calculator (35B), and the motion signal generator (39) has a plurality of motions between 0 and 1. The coefficient k is stored and the corresponding one of the stored values in response to the output signals of the motion level detector (35) and the line correlation detector (34).
ROM (Read) for outputting one as a motion coefficient (K)
Only Memory).

The principle of the motion level detector (35) and the motion signal generator (39) according to the present invention will be described. Figure 8
The low-pass filter (35A) for the color difference signal has a band (fsc3.58 MHz ± 0.
5 MHz) is removed and the remaining luminance signal is converted into an absolute value.

If the composite video signal is a still image (still pict
ure), the phases of two consecutive luminance signal components (that is, between the current frame signal and the frame signal one frame before or one frame signal after one frame) are in phase, Since the two continuous color signal components have a phase difference of 180 °, the frame difference signal shows only the color signal, and the residual luminance signal (ΔY) appears in the output of the low pass filter (35A). Since there is not, the absolute value calculator (35B) outputs a zero value.

On the contrary, when the composite video signal is a moving image, the phase of the luminance signal and the phase of the color signal between the two frames are different.

Therefore, the luminance signal component and the chrominance signal component simultaneously appear in the frame difference signal. When these difference signals pass through the low pass filter (35A), the color signal component (fsc ± 0.5 MHz) is removed and only the luminance signal component appears.

At this time, the output of the absolute value calculator (35B) has a value larger than zero, and the output signal of the absolute value calculator (35B) is input to the ROM. At this time, the line correlation detector (34 ) Output signal is also input at the same time. ROM
Selects and outputs one of a plurality of motion coefficients (K) stored in advance according to the input signal. The motion coefficient (K) is located in the range of 0 ≦ K ≦ 1, and the motion coefficient (K)
The closer the value is to “1”, the greater the movement.
The closer to “0”, the smaller the movement.

Next, the principle of the line correlation detector (34) will be described.

The line difference signal provided by the line comb filter (32) in FIG. 5 contains the residual luminance signal (ΔY), exactly, as described above. Therefore, the correlation detector (34) according to the present invention comprises a low pass filter (56) (5
8) is used to remove the color signal component, only the remaining luminance signal component (ΔY) is converted into an absolute value, and the line correlation is judged based on the magnitude of the absolute value.

The reason why the line correlation detector (34) and the motion level detector (35) are used together in the second embodiment of the present invention is as follows.

That is, the closer the output of the line correlation detector (34) is to "0", the better the line correlation is determined, and it is applied to the selection of the motion coefficient (K). is. In other words, if the line correlation is good even if the video signal slightly moves, the output signal of the line comb filter (32) is used.

The overall operation of the first and second embodiments of the present invention will be described below with reference to FIGS. 9 to 14.

4 and 7, the composite video signal (C
V) is supplied to the line comb filter (20) or (32) as a signal including a luminance signal (Y) and a color signal (C).

The line delay device (51) is provided with a composite video signal (C
V) is delayed by one line, and the line delay unit (52) has a function of delaying the one line delayed composite video signal (CV) by one line. This line comb filter (2
0) or (32) are two line delay devices (51) (52), two subtractors (53) (54), as shown in FIG.
It is composed of one adder (55) and a multiplexer (60). The subtractor (53) subtracts the original composite video signal (CV) from the composite video signal (CV) delayed by one line, and the subtractor (54) is delayed by the composite video signal (CV) delayed by two lines. The composite video signal (CV) is subtracted. The output signals of the subtracters (53) and (54) are added by the adder (55) and output. The subtractor (53)
The output signal of (54) and the output signal of the adder (55) are supplied to each input terminal (j, k, l) of the multiplexer (60).

On the other hand, the output signal of the subtractor (53),
The output signal of the subtractor (54) has its color signal components removed through low-pass filters (56) and (58), respectively, and only the residual luminance signal (ΔY) is extracted, and the residual luminance signal (ΔY) is extracted. ) Is converted into absolute values by the absolute value calculators (57) and (59) and then supplied to one input terminal of the comparators (CP ₅₁ ) (CP ₅₂ ).

As a result, the comparator (CP ₅₁ ) (CP
₅₂ ) compares the input residual luminance signal (ΔY) with the set threshold values (Vth ₂ , Vth ₃ ) and generates and outputs a corresponding comparison signal (S). The comparison signal (S) is further supplied to the multiplexer (60) and serves as a switching control signal for selecting a signal having a good line correlation among the input signals of the multiplexer (60).

The multiplexer (60) thus selects an input signal having a good line correlation and outputs it as a line color signal from the line comb filter (20) or (32).

The output signal (S) of the comparators (CP ₅₁ ) (CP ₅₂ ) is supplied to the motion signal generator (39) of FIG. 7 to reflect the line correlation in the generation of the motion coefficient (K), Then, it is also supplied to the switch (SW ₂₁ ) or (SW ₃₁ ), and the switch (SW ₃₁ ) or the switch (SW ₂₁ ) is a band pass filter (2) when the line correlation is bad.
The output signal of 1) or (33) is selected instead of the output signal of the line comb filter (20) or (32).

On the other hand, in FIGS. 4 and 7, the band pass filters (21) (33) and the color signal level detector (23).
(36) operates as follows.

As shown in FIG. 6, the band pass filter (2
1) (33) extracts a color subcarrier from the composite video signal (CV), and the extracted signal is an absolute value calculator (2).
After being converted into an absolute value in 3A), it is input to the comparator (23B) and compared with the threshold value (Vth ₄ ) set in the comparator (23B). As a result, the comparator (2
The output signal 3B) is used as a signal for determining what level (that is, magnitude) the band-filtered color signal has.

The output signal of the comparator (23B) in FIG. 6 is supplied to the switches (SW ₂₁ ) (SW ₃₁ ) together with the output signals of the line correlation detectors (22) and (34), so that the line correlation is very high. When it is defective or when there is no color subcarrier, the output signals of the bandpass filters (21) and (33) are controlled to be selected. Thus, the signals selected by the switches (SW ₂₁ ) (SW ₃₁ ) are filtered by the first filters (25) (41) only in the desired frequency band, and then the first filters (25) (4).
The subtraction unit (43) subtracts the composite video signal (CV) output through the delay units (24) and (42) synchronized with the output signal of 1). The output signal of the subtractor (43) is the final luminance signal (Y), and the switch (SW ₂₁ )
On the other hand, the color signal selected by (SW ₃₁ ) is band-pass filtered through the second filters (27) and (44) and output as the final color signal (C).

In FIG. 7, the frame color signal separated by the frame comb filter (31) and the color signal separated by the line comb filter (32) and the band pass filter (33) are the motions of the video signal. It is calculated in a proper ratio according to the degree.

That is, the frame comb filter (3
A motion level detector (35) based on the frame difference signal provided by 1) determines the degree of motion of a video signal, and the output signal of this detector (35) is a motion signal generator (39).
Is supplied to.

On the other hand, the output signal of the line correlation detector (34) is also supplied to the motion signal generator (39).

This motion signal generator (39) indicates the amount of motion of the video signal detected by the motion level detector (35) and the degree of line correlation detected through the line correlation detector (34). Judgment is made, and among the stored motion coefficients (K), those corresponding to these are calculated (37)
(38) is supplied.

The calculators (37) and (38) receive the motion coefficient (K) and perform the following calculations, respectively, and the output signals are added to each other by an adder (40). It

That is, when FC is a frame color signal (input signal of the arithmetic unit (37)), LC: line color signal (input signal of the arithmetic unit (38)), and V is an output signal of the adder (40). The output signal of the adder (40) can be expressed by equation (1).

V = (1−K) × FC + (K × LC) −−−−− (1) 0 ≦ K ≦ 1 The signals thus added are the same as those in FIG.
It is separated into a luminance signal (Y) and a color signal (C) through filters (41) and (44).

On the other hand, it may be necessary to compress the composite video signal (CV) in order to obtain high resolution. At this time, it is necessary to remove the interference component due to band compression,
Pre-filtering must be prioritized.

According to the embodiment of the present invention, it is possible to separate a luminance signal and a chrominance signal by using motion detection and line correlation and perform pre-filtering for band compression. That is, when band compression is required, as shown in FIG.
Instead of the band pass filters (21) (33) and the first filters (25) (41) in FIG. 7, a high pass filter having a predetermined frequency band may be used. Therefore, the pre-filtering is performed at the same time as the chrominance signal separation of the luminance signal without the separate pre-filter.

FIG. 9 shows the spectrum of the one-dimensional frequency of the composite video signal (CV). When the composite video signal (CV) of FIG. 9 is frequency band compressed as shown in FIG. 10A, the interference component can be removed. Figure 10
(A) Horizontally compresses the band-compressed composite video signal (CV).
It is the one-dimensional frequency spectrum of the vertical plane (fh-fv). That is, FIG. 10 (A) shows a state in which the spectrum of the frequency is superimposed by sub-nyquist sampling.

FIG. 10B shows the two-dimensional frequency spectrum of FIG. According to FIG. 11, it can be seen that there is no disturbing component and band compression is possible.

FIG. 12 shows the band pass filters (21) (3
After separating the color signals using 3), the two-dimensional frequency spectrum of the horizontal-vertical plane (fh-fv) plane, which represents the case where only the luminance signal is frequency band compressed as shown in FIG. Is.

Display A here represents the band-compressed spectrum.

FIG. 13 shows the pre-filtering effect of band compression when band compression is performed only on the luminance signal after separating the color signal using the line comb filter (20) or (32) by detecting the motion of the video signal. It is a frequency band spectrum of a time-vertical (ft-fv) plane that appears.

FIG. 14 shows a time-frequency in the vertical (ft-fv) plane showing the pre-filtering effect when band-compressing only the luminance signal after separating the signal using the frame comb filter by the motion detection. It is a band spectrum.

As described above, the motion of the video signal is detected from the line correlation between the current line and the signal before and after the first line and the frame difference signal, and the suitable luminance signal (Y) and chrominance signal (C) are detected. It is possible to perform pre-filtering for removing the interference component in the case of band compression without using another filter.

In the above embodiment, the composite video signal is N
Although the TSC system signal is used, the PAL system signal is similar, and therefore the signal is not limited to the NTSC signal.

[0091]

As described above, according to the present invention,
When separating a luminance signal and a chrominance signal, in the case of a moving image, a color signal with a good line correlation is selected by detecting the line correlation and the movement of the image signal, and separated into a good quality luminance signal and a color signal. You can get it.

Therefore, when this is applied to a TV receiver or a high quality VCR, there is an effect that a good image can be obtained.

Further, when compressing the frequency band of the composite video signal, no separate pre-filtering is required to remove the interference component, so that the structure of the TV receiver or VCR can be simplified and the signal It can be applied to all systems that record and reproduce by compressing the frequency band.

[Brief description of drawings]

FIG. 1 is a block diagram showing a conventional system for separating a luminance signal and a chrominance signal using a frame comb filter and a line comb filter.

FIG. 2 is a block diagram showing a conventional luminance signal and chrominance signal separation system using only a line comb filter.

FIG. 3A is a one-dimensional frequency spectrum showing the arrangement of luminance signals and color signals on a line, and FIG. 3B is a one-dimensional frequency spectrum showing the arrangement of luminance signals and color signals on a frame. is there.

FIG. 4 is a block diagram showing a luminance signal and chrominance signal separation system according to a first embodiment of the present invention.

5 is a detailed block diagram of the line comb filter and line correlation detector in FIG. 4. FIG.

FIG. 6 is a detailed block diagram of the color signal level detector in FIG.

FIG. 7 is a block diagram showing a luminance signal and chrominance signal separation system according to a second embodiment of the present invention.

8 is a block diagram showing a detailed configuration of a motion level detector and a motion signal generator in FIG.

FIG. 9 is a diagram of a one-dimensional frequency spectrum of a composite video signal.

10A is a diagram of a one-dimensional frequency spectrum obtained by band-compressing the signal of FIG. 9, and FIG. 10B is a diagram of a vertical-horizontal two-dimensional frequency spectrum of the signal of FIG. 9.

FIG. 11 is a diagram of a vertical-horizontal two-dimensional frequency spectrum showing a case where only the luminance signal is band-compressed after separating the color signal by the line comb filter.

FIG. 12 is a diagram of a vertical-horizontal two-dimensional frequency spectrum showing a case where only a luminance signal is band-compressed after separating a color signal by a bandpass filter.

FIG. 13 is a diagram of a vertical-horizontal two-dimensional frequency spectrum showing a case where only the luminance signal is band-compressed after separating the color signal by the line comb filter.

FIG. 14 is a vertical diagram showing a case where only the luminance signal is band-compressed after the color signals are separated by the frame comb filter.
It is a figure of a horizontal two-dimensional frequency spectrum.

[Explanation of symbols]

20, 32 line comb filter 21, 33 band pass filter 22, 34 line correlation detector 23, 36 color signal level detector 24, 42 delay device 25, 41 first filter 27, 44 second filter 26, 43 subtractor SW ₂₁ , SW ₃₁ switch 31 frame comb filter 35 motion level detector 37, 38 calculator 39 motion signal generator 40 adder

Claims (22)

[Claims] 1. A line comb shape in which a plurality of line difference signals between lines are obtained from an input composite video signal, and one of the plurality of line difference signals having a good line correlation is output as a line color signal by a control signal. Filtering means, first filtering means for extracting a color signal from the composite video signal and outputting the color signal, detecting a correlation between lines using the plurality of line difference signals, and outputting the detected signal to the line comb filtering means Line correlation detection means provided as a control signal, color signal level detection means for detecting the level of the color signal output from the first filtering means, color signal of the first filtering means, and line of the line comb filtering means A color signal is input to control the detection signal of the line correlation detection means and the output signal of the color signal level detection means. Switching means for selecting and outputting one of the two input signals as a signal, second filtering means for filtering the output signal of the switching means and outputting a color signal component, filtering the output signal of the switching means Third filtering means for outputting the final color signal, delay means for delaying the composite video signal for a predetermined time so as to be synchronized with the generation of the output signal of the second filtering means, and second filtering from the output signal of the delay means. A luminance signal and chrominance signal separation system, comprising: subtraction means for subtracting the output signal of the means to output the final luminance signal. 2. A luminance signal and chrominance signal separation system comprising:
The luminance signal / chrominance signal separation system according to claim 1, wherein the first filtering means and the second filtering means are high-pass filters in the case of a system for compressing a frequency band. 3. The luminance signal and chrominance signal separation system according to claim 1, wherein the first filtering means to the third filtering means are band pass filters. 4. The first line delay element for delaying the composite video signal by one line, and the second line delay element for delaying the output signal of the first line delay element by one line. A first subtractor for subtracting the composite video signal from the output signal of the first line delay element, a second subtractor for subtracting the output signal of the first line delay element from the output signal of the second line delay element, A subtracter, an adder for adding the output signals of the first subtractor and the second subtractor, and an output signal of the first subtractor, the second subtractor and the adder, respectively, and the line correlation detection means 2. The luminance signal according to claim 1, comprising a multiplexer that outputs one having a good line correlation as a line color signal in response to an external control signal that is output. Signal separation system. 5. The line correlation detecting means includes a first low-pass filter for low-pass filtering the output signal of the first subtractor to remove a color signal component, and an output signal of the second subtractor. A second low-pass filter for removing a color signal component by low-pass filtering; a first absolute value calculator for converting the residual luminance signal output from the first low-pass filter into an absolute value; A second absolute value calculator for converting the residual luminance signal output from the second low-pass filter into an absolute value; comparing the output signal of the first absolute value calculator with a set threshold value; A first comparator for providing a result value to the multiplexer as an external control signal, and comparing the output signal of the second absolute value calculator with a set threshold value, and the result value for the multiplexer. Luminance signal and the chrominance signal separation system according to claim 4, characterized in that it comprises a second comparator, for providing an external control signal. 6. The luminance signal / chrominance signal separation system according to claim 4, wherein the line comb filtering means further comprises a line delay element, a subtractor and an adder for performing the same function. 7. The luminance signal and chrominance signal separation system according to claim 5, wherein the line correlation detection means further comprises a low pass filter, an absolute value calculator and a comparator for performing the same function. 8. The first and second line delay elements are:
The luminance signal and chrominance signal separation system according to claim 4, which is a line memory. 9. The color signal level detecting means is set as an absolute value calculator for obtaining an absolute value of the color signal output from the first filtering means, and an output signal of the absolute value calculator. The luminance signal and chrominance signal separation system according to claim 1, further comprising: a comparator for comparing the threshold value and a resultant value as a switching control signal of the switching means. 10. A frame comb filtering means for obtaining a one-frame difference signal between adjacent frames from an input composite video signal and outputting the frame difference signal as a frame color signal; Line-comb filtering means for obtaining the line-difference signal of the line-combination signal and selecting one having a good line correlation among a plurality of line-difference signals by an external control signal and outputting it as a line-color signal; Line correlation detecting means for detecting the correlation between the lines using the line difference signal, and supplying a signal corresponding to the detected signal to the line comb filtering means as a control signal; First filtering means for passing only a color signal of a video signal, the first filter ring Color signal level detecting means for detecting the level of a color signal outputted from the means, and a color signal output from the first filtering means,
A line color signal output from the line comb filtering unit is input, and one of the two input signals is selectively output using the output signals of the line correlation detecting unit and the color signal level detecting unit as control signals. Switching means, motion level detecting means for detecting the degree of motion of the video signal from the frame difference signal provided from the frame comb filtering means, in response to the output signal of the line correlation detecting means and the output signal of the motion level detecting means Motion signal generating means for generating a motion coefficient; first calculating means for calculating and outputting using the output signal of the switching means and the motion coefficient; and the output signal of the frame comb filtering means and a set reference value. Second calculating means for calculating and outputting a value obtained by calculating a motion coefficient, the first performance Means for adding the output signals of the means and the second computing means, a second filtering means for filtering the output signal of the adding means and outputting only color signal components, and a final color by filtering the output signal of the adding means Third filtering means for outputting as a signal, delay means for delaying the composite video signal so as to be synchronized with the generation of the output signal of the second filtering means, and subtracting the output signal of the second filtering means from the output signal of the delay means And a subtraction means for outputting the resultant value as a final luminance signal, and a luminance signal and chrominance signal separation system. 11. The luminance signal and chrominance signal separation system according to claim 10, wherein the first to third filtering means are band pass filters for passing only chrominance signal components. 12. The first filtering means and the second filtering means are high-pass filters when the luminance signal and chrominance signal separation system is a system for compressing a frequency band. 1
The luminance signal and chrominance signal separation system according to 0. 13. The line comb filtering means includes: a first line delay element for delaying the composite video signal by one line; and a second line delay for delaying the output signal from the first line delay element by one line. An element, a first subtractor for subtracting a line signal before one line with a current line signal, a second subtractor for subtracting a current line signal for a line signal after one line, the first subtractor and a second subtractor Which has a good line correlation by inputting the output signals of the first subtractor, the second subtractor and the adder, and the external control signal output from the line correlation detecting means. 11. The luminance signal and chrominance signal separation system according to claim 10, comprising a multiplexer for outputting as a line chrominance signal. 14. The line correlation detecting means includes a first low-pass filter for low-pass filtering the output signal of the first subtractor to remove a color signal component, and an output signal of the second subtractor. A second low-pass filter for removing a color signal component by low-pass filtering; a first absolute value calculator for converting the residual luminance signal output from the first low-pass filter into an absolute value; A second absolute value calculator for converting the residual luminance signal output from the second low-pass filter into an absolute value; comparing the output signal of the first absolute value calculator with a set threshold value; A first comparator for providing a result value to the multiplexer as an external control signal, and an output signal of the second absolute value calculator are compared with a set threshold value, and the result value is obtained by the multiplex. Luminance signal and the chrominance signal separation system according to claim 13, characterized in that it comprises a second comparator, for providing an external control signal to. 15. The luminance signal / chrominance signal separation system according to claim 13, wherein the line comb filtering means further comprises a line delay element, a subtractor and an adder to perform the same function. 16. The luminance signal and chrominance signal separation system according to claim 14, wherein the line correlation detection means further comprises a low pass filter, an absolute value calculator and a comparator to perform the same function. 17. The first and second line delay elements include:
14. The luminance signal and chrominance signal separation system according to claim 13, which is a line memory. 18. The color signal level detecting means includes an absolute value calculator for obtaining an absolute value of the color signal output from the first filtering means, and an output signal of the absolute value calculator and a set threshold value. 11. The luminance signal and chrominance signal separating system according to claim 10, further comprising: a comparator for comparing the value with a value and outputting the resulting value as a switching control signal of the switching means. 19. The low-pass filter, wherein the motion level detecting means low-pass filters the frame difference signal provided from the frame comb-shaped filtering means to remove color signal components and then outputs the low-pass filter, and the low-pass filter. 11. The luminance signal and chrominance signal separation system according to claim 10, further comprising an absolute value calculator for obtaining an absolute value of the remaining luminance signal component of the output signal of the filter. 20. The motion signal generating means stores a plurality of motion coefficient values and, in response to the output signals of the line correlation detecting means and the motion level detecting means, a corresponding one of the plurality of motion coefficient values. 11. The luminance signal and chrominance signal separation system according to claim 10, which is a memory for selectively outputting. 21. The luminance signal / color signal separation system according to claim 20, wherein the memory is a read-only memory. 22. The reference value of the second computing unit is 1,
When the motion coefficient (k) is 0 ≦ k ≦ 1, the first calculation means multiplies the output signal of the switching means and the motion coefficient (k), and the second calculation means outputs the frame comb filtering means. 11. Luminance signal and chrominance signal separation system according to claim 10, characterized in that the signal is multiplied by (1-motion coefficient (k)).