JP3196616B2 - Luminance signal color signal separation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an apparatus for separating a luminance signal and a chrominance signal by three-dimensional processing using inter-frame correlation.

[0002]

2. Description of the Related Art In recent years, the performance of a luminance signal / color signal separating apparatus has been remarkably improved by digital processing. In particular, three-dimensional processing using frame correlation has been generally put to practical use even at a consumer level in accordance with a reduction in the price of an image memory. Is being done. As a conventional luminance signal / color signal separation apparatus, for example,
No. 74088.

A conventional luminance signal / chrominance signal separation apparatus will be described below. FIG. 5 shows a block diagram of a conventional luminance signal / color signal separation apparatus. In FIG. 5, reference numeral 1 denotes an input terminal for inputting a composite video signal. A color signal output terminal 2 outputs a separated color signal. A luminance signal output terminal 3 outputs a separated luminance signal. Reference numeral 4 denotes a one-frame delay unit that delays the input composite video signal by one frame. Reference numeral 5 denotes a subtracter, which obtains a one-frame differential signal by subtracting the input composite video signal and the composite video signal delayed by one frame. Reference numeral 6 denotes a motion detection circuit, which includes a low-pass filter 7, a threshold level generator 8, a subtractor 9, and a spatiotemporal filter 10,
A motion detection signal is obtained from one frame difference signal. Reference numeral 11 denotes a two-dimensional color signal separation circuit that performs intra-field processing, and obtains a moving color signal which is a color signal at the time of movement from the input composite video signal. Reference numeral 12 denotes a switch, which switches the one-frame difference signal between a moving color signal and a moving color signal in accordance with a motion detection signal to obtain a separated color signal as a still color signal which is a color signal in a stationary state.
Reference numeral 13 denotes a subtractor, which obtains a separated luminance signal by subtracting the separated color signal from the composite video signal.

[0004] The operation of the luminance signal / chrominance signal separation device configured as described above will be described below. First, the composite video signal input from the input terminal 1 is delayed by one frame by the one-frame delay unit 4 and then subtracted from the original composite video signal by the subtracter 5 to obtain a one-frame differential signal. . Since this composite video signal has a perfect frame correlation if it is a still image signal, one frame difference signal is only a complete still color signal. However, in the case of a moving image signal, the one-frame difference signal is a signal in which the motion component of the luminance signal and the stationary component of the color signal are mixed. Therefore, the one-frame difference signal is separated by the low-pass filter 7 into only the low-frequency motion component of the luminance signal, and is compared with the threshold value of the threshold level generator 8 by the subtracter 9. If the level is equal to or higher than the threshold level, it is determined that a motion has occurred, and a spatiotemporal filter 10 performs an integration process on the output to obtain a motion detection signal.

When the motion detection signal is not output, it is determined that the camera is stationary, and the switch 12 is switched to the S side, and the one-frame difference signal, which is a still color signal, is used as a separated color signal as a color signal output terminal 2. Output to When the motion detection signal is output, it is determined that the motion is occurring, the switch 12 is switched to the M side, and the two-dimensional color signal separation circuit 11 is switched.
The obtained moving color signal is output to the color signal output terminal 2 as a separated color signal.

On the other hand, the separated luminance signal is obtained by subtracting the separated color signal from the composite video signal by the subtractor 13 and output to the luminance signal output terminal 3. Next, another example of a conventional luminance signal / color signal separation apparatus will be described. FIG.
FIG. 5 is a block diagram of another example of the conventional luminance signal / color signal separation device, which reduces the capacity of the image memory used for the one-frame delay unit 4 with respect to the conventional luminance signal / color signal separation device in FIG. In this case, a thinning process is used to perform the processing. 6, the same components as those in FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted.

In FIG. 6, reference numeral 21 denotes a first thinning-out processing circuit, which performs thinning-out processing on a composite video signal sampled by a clock obtained by multiplying a subcarrier in accordance with the subcarrier phase. Reference numeral 22 denotes a first one-frame delay unit, which delays the thinned composite video signal by one frame.
23 is a subtractor, which calculates the difference between the composite video signal subjected to the thinning process and the composite video signal delayed by one frame,
A thinned one frame difference signal is obtained. Reference numeral 24 denotes a first interpolation processing circuit, which performs an interpolation process on the thinned one-frame difference signal so as to have the original sampling rate to obtain a still color signal. A low-pass filter 25 separates a low-frequency component of the luminance signal from the composite video signal. Reference numeral 26 denotes a second decimation processing circuit, which decimates the sampling rate of the separated low-frequency component of the luminance signal. Reference numeral 27 denotes a second one-frame delay unit for reducing the luminance signal low-frequency component subjected to the thinning-out processing to one.
Delay by frame. Reference numeral 28 denotes a subtractor which obtains a difference between the luminance signal low-frequency component subjected to the decimation process and the luminance signal low-frequency component delayed by one frame to obtain a decimation luminance signal low-frequency motion component. Reference numeral 29 denotes a second interpolation processing circuit which performs interpolation processing on the thinned-out luminance signal low-frequency motion component so as to have the original sampling rate to obtain a luminance signal low-frequency motion component.

The operation of the luminance signal / chrominance signal separation device configured as described above will be described below with reference to FIG. FIG. 7 is a reference diagram showing an example of a state of a thinning process in the conventional luminance signal / color signal separation device shown in FIG. First, the composite video signal input from the input terminal 1 is sampled with a clock that is four times the subcarrier as shown in FIG. 7A. Then, the composite video signal is subjected to the decimating process to １ ／ centering on the subcarrier frequency in the first decimating circuit 21 as shown in FIG. 7B. Thereafter, the signal is delayed by one frame in the first one-frame delay unit 22 and is subtracted from the composite video signal that has been subjected to the original decimation process in the subtractor 23, thereby providing a decimation 1
A frame difference signal is obtained, and a first interpolation processing circuit 24
Is subjected to an interpolation process so as to obtain the original sampling rate, thereby obtaining a one-frame difference signal. This one-frame difference signal has some aliasing distortion components due to the thinning-out process performed on the way, but the thinning-out process is performed around the sub-carrier frequency, and the band limitation by the filter is limited. Since it is not applied at all, an almost perfect still color signal is obtained.

The composite video signal is supplied to a low-pass filter 2.
At 5, the low-frequency component of the luminance signal is separated, and is separated by the second thinning-out processing circuit 26 into a quarter as shown in FIG.
Is subjected to a thinning process. Thereafter, the signal is delayed by one frame in the second one-frame delay unit 27, and is subtracted from the composite video signal that has been subjected to the original decimation process in the subtractor, thereby obtaining a thinned luminance signal low-frequency motion component. The interpolation processing is performed by the second interpolation processing circuit 29 so as to return to the original sampling rate, thereby obtaining a luminance signal low-frequency motion component. Although the luminance signal low-frequency motion component is subjected to thinning-out processing in the middle, since the band-limiting is applied to the sub-Nyquist band by the low-pass filter 25 in advance, it is exactly the same as when no thinning-out processing is performed. A luminance signal low-frequency motion component is obtained. Therefore, it is compared with the threshold value by the threshold level generator 8 in the subtractor 9, and if it is equal to or higher than the threshold level, it is determined that a motion has occurred, and its output is integrated by the spatiotemporal filter 10. By performing the processing, a motion detection signal is obtained.

When the motion detection signal is not output, the switch 12 is switched to the S side, and the still color signal is output to the color signal output terminal 2 as a separated color signal. When the motion detection signal is output, it is determined that the motion is occurring, the switch 12 is switched to the M side, and the moving color signal obtained from the two-dimensional color signal separating circuit 11 is used as the separated color signal as the color signal output terminal Output to

Further, the separated luminance signal is obtained by subtracting the separated color signal from the composite video signal by the subtractor 13 and output to the luminance signal output terminal 3. By using the thinning-out processing in this manner, a total of 3/4 thinnings can be realized, that is, 1/2 by the first one-frame delay unit 22 and 1/4 by the second one-frame delay unit 27. In addition, the image memory capacity can be reduced to 3/4 as compared with the case where no thinning is performed.

[0012]

However, in the above-mentioned conventional configuration, the luminance signal low-frequency motion component is compared with the threshold value of the threshold level generator 8 by the subtracter 9, and when it is higher than the threshold level, Therefore, even if a luminance signal low-frequency motion component is generated, if the luminance component is lower than the threshold value, the motion detection signal cannot be obtained, and the motion detection signal is obtained. Leakage occurs.

For this reason, in the luminance signal chrominance signal separation device shown in FIG. 5, the after-image disturbance of the luminance signal occurs due to the motion detection omission, and in the luminance signal chrominance signal separation device shown in FIG. There has been a problem that a false signal is obstructed because a luminance signal low-frequency motion component is folded back into a still color signal due to detection omission. In order to solve this problem, it is only necessary to greatly lower the threshold level. However, if this is done, the probability of generating a motion detection signal even at rest due to noise or the like included in the input composite video signal increases. , The three-dimensional processing effect is reduced.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method in which a one-frame differential signal is passed through a first low-pass filter, and then passed through a first low-pass filter. A still color signal from which the luminance signal motion leakage component has been removed by passing the signal through a narrow band second low-pass filter to separate the motion leakage component of the luminance signal and subtracting the motion leakage component from the one-frame difference signal. , And subtracting this still color signal from the original composite video signal, it is possible to obtain a separated luminance signal that does not cause afterimage interference.

Further, the low-frequency one-frame difference signal obtained by passing the composite video signal through the first low-pass filter is passed through a second low-pass filter having a band narrower than that of the first low-pass filter. In this way, after separating the motion leakage component of the luminance signal, by subtracting from the one-frame difference signal, it is possible to obtain a separated color signal that does not cause false color signal interference.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a frame delay means for delaying an input composite video signal by one frame and obtaining a difference between signals before and after the composite video signal to obtain a one-frame difference signal. A low-pass filter and a motion detection means for obtaining a motion detection signal by detecting a predetermined level or more;
To separate a motion leakage component of the luminance signal by passing through a second low-pass filter having a band narrower than that of the low-pass filter, and subtract the motion leakage component from the one-frame difference signal to obtain a still color signal. A motion leakage component removing means.

According to this structure, the motion leakage signal removing means separates the motion leakage component from the one-frame differential signal by the second low-pass filter having a band narrower than that of the first low-pass filter. By subtracting the component from the one-frame difference signal, a still color signal that does not include a motion leakage component is obtained. Then, by subtracting a still color signal that does not include a motion leakage component from the composite video signal, a separated luminance signal that does not cause afterimage interference is obtained.

[0018] Further, the input composite video signal is sampled in synchronization with the sub-carrier, and a first decimating means for decimating it according to the sub-carrier phase, and an output of the first decimating means is delayed by one frame, A first frame delay unit that obtains a one-frame difference signal by taking a difference between signals before and after the first signal and a second thinning-out process after passing a sampled composite video signal through a first low-pass filter; And the output is 1
A second frame delay unit that obtains a low-frequency 1-frame differential signal by delaying the frame, taking a difference between signals before and after the delay, and performing a second interpolation process according to a second thinning process; A motion detecting means for obtaining a motion detection signal by detecting a predetermined level or more of the one-frame difference signal; and a second low-pass filter having a narrower band than the first low-pass filter. To separate the motion leakage component of the luminance signal,
After performing the third thinning process according to the thinning means,
A motion-leakage-component removing unit that obtains a still color signal by subtracting the output from the frame difference signal and performing a first interpolation process on the output according to the first thinning unit;

With this configuration, the motion-leakage signal removing means separates the motion-leakage component from the low-frequency one-frame differential signal with the second low-pass filter having a band narrower than the first low-pass filter. After performing the third decimation process according to the first decimation unit on the motion leakage component, the motion leakage component is subtracted from the one-frame difference signal, and the output is subjected to the first interpolation process according to the first decimation unit. A still color signal from which the aliasing luminance signal low-frequency motion component has been removed is obtained. Therefore, a separated color signal free from false color signal interference is obtained.

[0020]

An embodiment of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a block diagram showing a luminance signal / chrominance signal separation device according to a first embodiment of the present invention. 1, the same components as those in FIG. 5 are denoted by the same reference numerals.

In FIG. 1, reference numeral 1 denotes an input terminal for inputting a composite video signal. A color signal output terminal 2 outputs a separated color signal. A luminance signal output terminal 3 outputs a separated luminance signal. Reference numeral 4 denotes a one-frame delay unit that delays the input composite video signal by one frame. Reference numeral 5 denotes a subtracter, which obtains a one-frame differential signal by subtracting the input composite video signal and the composite video signal delayed by one frame. Reference numeral 6 denotes a motion detection circuit, which includes a first low-pass filter 7, a threshold level generator 8, a subtractor 9, and a spatiotemporal filter 10, and obtains a motion detection signal from one frame difference signal.

Reference numeral 50 denotes a second low-pass filter, which has a narrower pass band than the first low-pass filter 7 and 1.
The motion leakage component of the luminance signal is separated from the frame difference signal. Reference numeral 51 denotes a subtractor, which obtains a still color signal by subtracting a motion leakage component of a luminance signal from a one-frame difference signal. Reference numerals 52, 53, and 54 denote delay units for timing adjustment.

Reference numeral 11 denotes a two-dimensional color signal separation circuit for performing intra-field processing, and obtains a moving color signal which is a color signal at the time of movement from the input composite video signal. A switch 12 switches between a still color signal and a moving color signal according to a motion detection signal to obtain a separated color signal. Reference numeral 13 denotes a subtractor, which obtains a separated luminance signal by subtracting the separated color signal from the composite video signal.

The operation of the luminance signal / chrominance signal separation device configured as described above will be described below with reference to FIG. FIG. 2 is a signal spectrum diagram of each part of the luminance signal chrominance signal separation device of the present invention shown in FIG. First,
The composite video signal input from the input terminal 1 has a spectrum in which the luminance signal (Y) and the chrominance signal (C) are mixed as shown in FIG. After the composite video signal is delayed by one frame in the one-frame delay unit 4, the subtracter 5 subtracts the composite video signal from the original composite video signal to obtain a one-frame difference signal. As shown in FIG. 2B, this one-frame difference signal is only a complete still color signal (CS) in the case of a still image signal, but the motion component of the luminance signal and the color signal in the case of a moving image signal. Is a signal in which the stationary components are mixed. Therefore, this one-frame difference signal is represented by (b) in FIG.
First low-pass filter 7 having the characteristic (LPF1) shown in FIG.
Separates only the low-frequency motion component (YLM) of the luminance signal,
This is compared with the threshold value K by the threshold level generator 8 in the subtractor 9, and if it is equal to or higher than the threshold level, it is determined that a motion has occurred, and the output is integrated by the spatiotemporal filter 10. To obtain a motion detection signal. Here, the low-pass filter 7 also applies the low-frequency component (CL) of the still color signal to the still image signal as shown in FIG.
S). However, it is necessary to set the threshold value K so that a motion detection signal is not generated by this component. On the other hand, if the low-frequency motion component (YLM) of the luminance signal is small and equal to or smaller than the threshold value K in the moving image signal, no motion detection signal is generated. ) Becomes a motion-leakage component and is mixed into the still color signal, causing afterimage disturbance in the separated luminance signal.

Therefore, the characteristic (LPF2) shown in FIG.
Is separated from the one-frame difference signal by the second low-pass filter 50 having the following equation, and is subtracted from the original one-frame difference signal by the subtracter 51 to obtain the luminance signal motion-leakage component. Is obtained. When the motion detection signal is not output, it is determined that the camera is stationary, the switch 12 is switched to the S side, the still color signal is output to the color signal output terminal 2 as a separated color signal, and the motion detection signal is output. When the motion is detected, the switch 12 is switched to the M side, and the moving color signal obtained from the two-dimensional color signal separation circuit 11 is output to the color signal output terminal 2 as a separated color signal (see FIG. d)).

On the other hand, the separated luminance signal is obtained by subtracting the separated color signal from the composite video signal by the subtractor 13 and output to the luminance signal output terminal 3 (FIG. 2 (e)). In the configuration shown in FIG. 1, the second low-pass filter 50 is provided after the first low-pass filter 7 to separate the motion leakage component of the luminance signal.
May be provided at a subsequent stage, and the motion leakage component of the luminance signal is configured to be subtracted from the one-frame difference signal. However, the motion leakage component is added to the separated luminance signal only when no motion detection signal is generated. Even if it configures, the effect does not change.
Therefore, it goes without saying that the configuration of the present invention is not limited to the present embodiment.

As described above, according to this embodiment, the motion leakage component is separated by the second low-pass filter having a band narrower than that of the first low-pass filter, and the motion leakage component is separated by one frame difference. By subtracting from the signal, a still color signal containing no motion leakage component can be obtained, and thereby a separated luminance signal free from afterimage interference can be obtained. (Embodiment 2) Next, another embodiment of the present invention will be described.

FIG. 3 is a block diagram of a luminance signal / chrominance signal separating apparatus according to another embodiment of the present invention. In the figure, the same components as those in FIG. 6 are denoted by the same reference numerals. In FIG. 3, reference numeral 1 denotes an input terminal, which inputs a composite video signal sampled by a clock multiplied by a subcarrier. A color signal output terminal 2 outputs a separated color signal. A luminance signal output terminal 3 outputs a separated luminance signal. Reference numeral 21 denotes a first decimation processing circuit, which performs decimation processing on the input composite video signal according to the subcarrier phase. Reference numeral 22 denotes a first one-frame delay unit, which delays the thinned composite video signal by one frame. Numeral 23 denotes a subtracter, which obtains a difference between the composite video signal subjected to the thinning process and the composite video signal delayed by one frame to obtain a thinned one-frame difference signal. Reference numeral 6 denotes a motion detection circuit, which includes a first low-pass filter 25, a second thinning-out processing circuit 26, a second one-frame delay unit 27, a subtracter 28, a second preserving time processing circuit 29, and a threshold value. It comprises a level generator 8, a subtractor 9, and a spatiotemporal filter 10, and obtains a motion detection signal from a low-frequency one-frame difference signal of a luminance signal.

Reference numeral 60 denotes a second low-pass filter, which has a narrower pass band than the first low-pass filter 25.
The motion leakage component of the luminance signal is separated from the low-frequency one-frame difference signal of the luminance signal. Reference numeral 61 denotes a third thinning processing circuit, which operates in the same manner as the first thinning processing circuit 21. 62
Denotes a subtractor, which obtains a thinned still color signal by subtracting the motion leakage component of the luminance signal from the thinned one frame difference signal. 63, 64 and 65 are delay units for timing adjustment.

Reference numeral 24 denotes a first interpolation processing circuit, which performs interpolation processing so that the thinned still color signal has the original sampling rate. Reference numeral 11 denotes a two-dimensional color signal separation circuit that performs intra-field processing, and obtains a moving color signal which is a color signal at the time of movement from the input composite video signal. Reference numeral 12 denotes a switch,
A still color signal and a moving color signal are switched in accordance with the motion detection signal to obtain a separated color signal. Reference numeral 13 denotes a subtractor, which obtains a separated luminance signal by subtracting the separated color signal from the composite video signal.

The operation of the luminance signal / chrominance signal separation device configured as described above will now be described with reference to FIGS.
This will be described with reference to FIG. FIG. 4 is a signal spectrum diagram of each part in the luminance signal color signal separation device of the present invention shown in FIG. First, the composite video signal input from the input terminal 1 is, for example, as shown in FIG.
It is sampled by the multiplied clock, and has a mixed spectrum of the luminance signal (Y) and the chrominance signal (C) as shown in FIG. This composite video signal is subjected to a decimating process by half around the sub-carrier frequency as shown in FIG. 7B by the first decimating circuit 21 and shown in FIG. 4B. As described above, the spectrum has a spectrum (Y ′ and C ′) folded in a half band around the subcarrier frequency.
Thereafter, the signal is delayed by one frame by the first one-frame delay unit 22 and is subtracted from the composite video signal subjected to the original decimation process by the subtracter 23, thereby obtaining a thinned one-frame difference signal ((e in FIG. 4). )). Further, the composite video signal is separated by a low-pass filter 25 into a low-frequency component (YL) of the luminance signal as shown in FIG. As shown in (c) of FIG.
/ 4 is subjected to a thinning-out process and has a spectrum folded back at a half of the subcarrier frequency as shown in FIG. Thereafter, the signal is delayed by one frame in the second one-frame delay unit 27 and is subtracted from the composite video signal subjected to the original thinning-out processing in the subtracter 28, thereby obtaining a low-frequency one-frame difference of the thinned luminance signal. That is, the low-frequency motion component of the thinned luminance signal is obtained, and the second interpolation processing circuit 29
By performing interpolation processing so as to obtain the original sampling rate at, a luminance signal low-frequency motion component is obtained. Although the luminance signal low-frequency motion component is subjected to the decimation process on the way, since the sub-Nyquist band is band-limited by the low-pass filter 25 in advance, it is exactly the same as when no decimation process is performed. A luminance signal low-frequency motion component is obtained. Therefore, the difference is compared with the threshold value by the threshold level generator 8 in the subtractor 9, and if it is equal to or higher than the threshold level, it is determined that a motion has occurred, and the output thereof is integrated by the spatiotemporal filter 10. To obtain a motion detection signal.

On the other hand, in the decimated one-frame difference signal, as shown in FIG. 4E, the decimated still-color signal component (CS ') has substantially the same frequency as the still-color signal component when no decimating is performed. Although the spectrum has a spectrum, the motion leakage component (YLM ') of the decimated luminance signal has a spectrum in the same band as the color signal due to the aliasing caused by the decimating processing. As a result, the luminance signal motion leakage component causes false color signal interference.
This thinned luminance signal motion leakage component cannot be separated by frequency division. Therefore, the signal (YLM) corresponding to the motion leakage component of the luminance signal is separated from the luminance signal low-frequency motion component by the second low-pass filter 60 having the characteristic (LPF2) shown in FIG. This is subjected to the decimation processing shown in FIG. 7B by the third decimation processing circuit 61 to thereby obtain a thinned luminance signal motion leakage component (YLM ′) having the spectrum shown in FIG. Can be obtained.

Then, this is subtracted by a subtractor 62 into a thinning 1
By subtracting from the frame difference signal, a decimated still color signal is obtained.
By performing the interpolation processing so that the sampling rate becomes the original sampling rate, it is possible to obtain a still color signal from which the luminance signal motion leakage component has been removed. This still color signal has some aliasing distortion components due to the thinning process performed on the way, but the thinning signal is thinned around the subcarrier frequency, and furthermore, there is no band limitation by the filter. Since it is not applied, an almost perfect still color signal is obtained.

When the motion detection signal is not output, the switch 12 is switched to the S side, and the still color signal is output to the color signal output terminal 2 as a separated color signal. When the motion detection signal is output, it is determined that the motion is occurring, the switch 12 is switched to the M side, and the moving color signal obtained from the two-dimensional color signal separating circuit 11 is used as the separated color signal as the color signal output terminal (FIG. 4 (h)).

Further, the separated luminance signal is obtained by subtracting the separated color signal from the composite video signal by the subtractor 13 and output to the luminance signal output terminal 3 ((i) in FIG. 4). It should be noted that the configuration of the present invention is not limited to the present embodiment alone, and may have various modifications. As described above, according to the present embodiment, the motion leakage component is separated from the luminance signal low band one frame difference signal by the second low pass filter having a narrower band than the first low pass filter, and the motion After subjecting the leak component to a third decimation process in accordance with the first decimation unit, a subtraction from the one-frame difference signal yields a separated color signal free from false color signal interference.

[0036]

As described above, according to the present invention, a motion-leakage component is separated by a narrow-band low-pass filter, and the motion-leakage component is subtracted from a one-frame differential signal, thereby achieving a separation that does not cause image sticking. A luminance signal can be obtained. As a result, it is possible to provide a higher-performance luminance signal / color signal separator.

Further, a motion-leakage component is separated from the luminance signal low-frequency one-frame differential signal by a narrow-band low-pass filter, and the motion-leakage component is subjected to a thinning process, and then subtracted from the one-frame differential signal. As a result, a separated color signal that does not cause false color signal interference is obtained. As a result, the memory for frame delay can be reduced without deteriorating the performance, and an inexpensive and high-performance luminance signal / color signal separation device can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram of a luminance signal / color signal separation device according to a first embodiment of the present invention;

FIG. 2 is a signal spectrum diagram of each part of the luminance signal / color signal separation device of FIG. 1;

FIG. 3 is a block diagram of a luminance signal / chrominance signal separation device according to a second embodiment of the present invention;

FIG. 4 is a signal spectrum diagram of each part of the luminance signal / color signal separation device of FIG. 3;

FIG. 5 is a block diagram showing an example of a conventional luminance signal / color signal separation device.

FIG. 6 is a block diagram showing another example of a conventional luminance signal / color signal separation apparatus.

FIG. 7 is a timing chart for explaining the operation of FIG. 3 or FIG. 6;

[Explanation of symbols]

 Reference Signs List 1 input terminal 2 color signal output terminal 3 luminance signal output terminal 4, 22, 27 1 frame delay unit 5, 9, 13, 23, 51, 62 subtractor 6 motion detection circuit 7, 25 first low-pass filter 8 Threshold level generator 10 spatiotemporal filter 11 two-dimensional color signal separation circuit 12 switcher 21 first thinning processing circuit 24 first interpolation processing circuit 26 second thinning processing circuit 29 second interpolation processing circuit 50, 60 second low-pass filter 61 third decimation processing circuit

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-89789 (JP, A) JP-A-2-174486 (JP, A) JP-A-3-240393 (JP, A) JP-A-1- 175484 (JP, A) JP-A-63-227294 (JP, A) JP-A-1-137789 (JP, A) JP-A-2-94891 (JP, A) JP-A 1-174088 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04N 9/44-9/78

Claims (2)

(57) [Claims] 1. A frame delay means for delaying an input composite video signal by one frame and obtaining a difference between the signals before and after the composite video signal to obtain a one-frame difference signal; A motion detection unit that obtains a motion detection signal by detecting a predetermined level or more after passing through the filter; and a second low-pass filter having a band narrower than the first low-pass filter for the one-frame difference signal. To remove a motion leakage component of the luminance signal by subtracting the motion leakage component from the one-frame difference signal to obtain a still color signal. A moving color signal separating means for separating a moving color signal by processing, the still color signal and the moving color signal are switched by the motion detection signal, and a separated color signal is output. By subtracting the separated chrominance signal from the color signal output means and the input composite video signal, a luminance signal output means for outputting the separated luminance signal, at least with the luminance-chrominance signal separator. 2. A first thinning means for sampling an input composite video signal in synchronization with a subcarrier, thinning the sampled signal in accordance with a subcarrier phase, and delaying an output of the first thinning means by one frame. By taking the difference between the signals before and after that, 1
First frame delay means for obtaining a frame difference signal; and after passing the sampled composite video signal through a first low-pass filter, a second thinning process is performed.
A second frame delay unit that obtains a low-frequency 1-frame differential signal by delaying the frame, taking a difference between signals before and after the delay, and performing a second interpolation process according to the second thinning process; Motion detection means for obtaining a motion detection signal by detecting a predetermined level or more of the low-frequency one-frame differential signal; and a second low-frequency signal having a narrower band than the first low-pass filter. After passing through a band-pass filter, the motion leakage component of the luminance signal is separated, and the motion leakage component is subjected to a third decimation process according to the first decimation unit, and then subtracted from the one-frame difference signal. The output is subjected to a first interpolation process according to the first decimation unit to obtain a still color signal. A moving-color signal separating unit that separates a signal, the still-color signal and the moving-color signal are switched by the motion detection signal, and a color-signal output unit that outputs a separated-color signal; A luminance signal output unit that outputs a separated luminance signal by subtracting the separated color signal.