KR940001442B1 - Luminance and chroma signal separation system - Google Patents

Abstract

The system comprises frame and line comb filters for outputting frame and line difference signals of the video signal respectively. A first filter extracts a chrominance signal from the video signal, and a line correlation detector senses the line correlations with respect to the line difference signals. A chrominance signal level senses a level of the output of the first filter. A moving level detector senses a moving level of the video signal based on the frame difference signal. A first operator governs the output of the switch and the moving factor, and a second operator controls the output of the frame comb filter and a value. An adder sums the outputs of the two operators, and a second filter filters the output of the adder to extract a chrominance signal. A third filter filters the output of the adder to output the final chrominance signal.

Description

Luminance Signal and Color Signal Separation System

1 is a block diagram showing a conventional separation system of a luminance signal and a color signal using a frame comb filter and a line comb filter.

2 is a block diagram showing a conventional system for separating a luminance signal and a color signal using only a line comb filter.

(A) and (b) are one-dimensional frequency spectrum diagrams showing the arrangement of luminance signals and color signals between lines between lines and frames, respectively.

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

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

6 is a detailed block diagram of a bandpass filter and a color signal level detector in FIG.

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

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

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

10 (a) and 10 (b) show a one-dimensional frequency spectrum obtained by band-compressing the spectrum of FIG. 9 and a vertical-horizontal two-dimensional frequency spectrum.

FIG. 11 is a vertical-horizontal two-dimensional frequency spectrum diagram illustrating a case where only a luminance signal is band-compressed after color signals are separated in a line comb filter. FIG.

12 is a vertical-horizontal two-dimensional frequency spectrum diagram illustrating a case where only luminance signals are band-compressed after color signals are separated by band pass filters.

FIG. 13 is a vertical-time two-dimensional frequency spectrum diagram illustrating a case where only a luminance signal is band-compressed after color signals are separated by a line comb filter. FIG.

FIG. 14 is a vertical-time two-dimensional frequency spectrum diagram illustrating a case where only a luminance signal is compressed by band after color signals are separated by a frame comb filter. FIG.

* Explanation of symbols for main parts of the drawings

20,32: line comb filter 21,33: bandpass filter

22,34: line correlation detector 23,36: color signal detector

24,42: delay 25,41: first filter

27,44: second filter 26,43: subtractor

SW ₂₁ , SW ₃₁ : Switch 31: Frame comb filter

35: motion detector 37,38: calculator

39: motion signal generator 40: adder

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for separating luminance and color signals from a composite video signal of a television broadcast such as NTSC, PAL, or SECAM. The present invention relates to a separation system of luminance and color signals suitable for obtaining high quality images in a high vision system such as a high definitino video cassette recorder.

FIG. 1 is a block diagram showing a conventional system for separating luminance and color signals using a frame and line comb filter, and FIG. 2 is a block diagram showing a conventional system for separating luminance and color signals using a line comb filter. Here, the frame means one screen of a television broadcast.

In the case of television broadcasting (e.g., NTSC system), one frame is composed of 525 lines, and is transmitted from a broadcasting pole of one (i.e. one frame) screen every 1/30 sec. In one frame, each 252.5th line in the odd and even numbers is sent out from the broadcasting station in an interlaced scanning method every 1/60 sec.

Thus, one frame consists of two fields. In NTSC, one line is composed of 15.75KHZ (64.5μsec).

As mentioned above, the one-frame signal used below refers to a 525-line delayed video signal (i.e., two pulses or one image after 1 / 30sec), and the frame difference signal is a frame signal one frame before or one frame from the current frame signal. This means that the current frame signal is subtracted from the frame signal after the frame.

That is, the frame difference signal is composed of only the color signal components because the luminance signal components are removed. The reason will be explained later. The comb filter used in FIGS. 1 and 2 will be described with reference to FIGS. 3A and 3B as follows.

FIG. 3 (a) shows the arrangement of luminance signals and color signals between lines in the NTSC television broadcasting signal in frequency spectrum, and FIG. 3 (b) shows arrangement of luminance signals and color signals between frames in NTSC television broadcasting signal. It is shown in the frequency spectrum.

As shown in Figs. 3A and 3B, the NTSC system television broadcast signal is a mixture of color signals and luminance signals, and the color signals and luminance signals are alternately arranged on the frequency spectrum. The comb filter is used to separate the color signal and the luminance signal from the composite video signal, respectively.

In the NTSC television broadcasting signal, the color signal is inverted in phase by 180 degrees for each line and also inverted by 180 degrees for each frame (i.e., every signal after 525 lines).

Therefore, when the composite video signal of two lines is added, the color signal is canceled because the phase is 180 °, and only the pure luminance signal is left. On the contrary, when the composite video signal of the two lines is subtracted, the luminance signal is canceled and only the color signal component remains. Therefore, using this principle, the luminance signal and the color 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 according to the configuration of FIG. 1 will be described.

When the composite video signal CV is input to the frame comb filter 1, the frame comb filter 1 separates the luminance signal and the color signal from the composite video signal CV in units of frames, and then calculates the separated frame color signal. Supplies).

At the same time, the composite video signal CV is supplied to the line comb filter 2, and the gynecomb filter 2 separates the luminance signal and the color signal in line units and supplies the separated line color signal to the calculator 5. .

On the other hand, the frame difference signal FD provided by the frame comb filter 1 is input to the motion detector 3 to detect the degree of motion of the video signal, and the motion detector 3 uses the frame difference signal to output the video signal. The motion coefficient K corresponding to the degree of motion of is obtained and then supplied to the calculators 4 and 5.

Here, this motion coefficient K is obtained by a value between 0 and 1 (0 ≦ K ≦ 1). That is, the closer the motion coefficient K is to 1, the more severe the motion of the video signal is. The calculator 4 multiplies and outputs the input frame color signal FC by subtracting the motion coefficient K from 1 (1-K), and the calculator 5 outputs the motion coefficient (C) to the input line color signal LC. Multiply K) and output it.

The output signals of the calculators 4 and 5 are added to each other in the adder 6, and the adder 6 outputs the added color signal to the bandpass filter 8.

In the NTSC television broadcasting signal, the color signal is located in the band of ± 0.5MHZ around the center frequency of 3.58MHZ when viewed in the frequency spectrum, so the signal output through the bandpass filter 8 is about 3MHZ-4.2MHZ, which is the desired band. Is the final color signal (C).

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 is supplied to the retarder 7 together with the frame comb filter 1 and the line comb filter 2, and is synchronized with the color signal C outputted through the band pass filter 8. It is output after a predetermined time delay.

The subtractor 9 outputs a signal obtained by subtracting the color signal C from the composite video signal CV delayed by a predetermined time as the final luminance signal Y.

Referring to the operation according to the configuration of Figure 2 as follows.

When the composite video signal CV is input to the line comb filter 11, the line comb filter 11 extracts the color signal from the composite video signal CV on a line-by-line basis and then converts the line color signal LC to the band pass filter 12. )

The band pass filter 12 extracts only a color signal component from the input line color signal LC, and extracts and outputs only the color signal C having a band of ± 0.5 MHz based on the center frequency fse.

At the same time, the line color signal LC is also supplied to the low pass filter 13, and the low pass filter 13 removes the color subcarrier from the input line color signal LC.

Therefore, the low pass filter 13 outputs only the residual luminance signal component? Y which does not contain the color signal.

As shown in FIG. 3A, since the color signal and the luminance signal overlap, the residual luminance signal component ΔY may be included even if the line color signal LC is separated by the line comb filter 11.

This residual luminance signal component? Y becomes even larger when it is a moving video signal.

The residual luminance signal component? Y is also converted by the absolute value calculator 14 and then applied to the non-inverting input terminal + of the comparator CP ₁ .

The comparator CP ₁ compares the absolute value with the set hold Vth ₁ applied to the inverting input terminal (−) and outputs the result as a switching control signal of the switch SW1.

Meanwhile, the composite video signal CV is also supplied to the delayer 15, and the delayer 15 is synchronized with the time supplied to the output signal subtracter 16 of the bandpass filter 12. Is delayed by a predetermined time and then supplied to the subtractor 16.

The subtractor 16 supplies the luminance signal obtained by subtracting the color signal C from the composite video signal CV to the retarder 17 and the band trap filter.

The output side of the delay device 17 is connected to the other input terminal (b) of the switch (SW ₁₎ of the output side of the one side input terminal (a) of the switch (SW _1), a band trap filter 18, a switch (SW ₁ ) Is controlled by a switch control signal output from the comparator CP1 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, it is a case of dot interference. In this case, the switch SW ₁ selects the output signal of the band trap filter 18, and conversely, the comparator CP _1. If the output signal of the?) Is a low level signal, the delay signal 17 selects the output signal.

The signal selected in this way is output as the final luminance signal (Y).

A conventional system for separating luminance and color signals using the above-mentioned line memory and frame memory is an IDTV receiver (Kiyoyuki Kawai et al., Toshiba Corporation Consumer Products Engineering Laboratory Yokohama, Japan, IEEE Transactions on Consumer Electronics, Vol. CE-33, No. 3, August 1987).

However, according to the above prior art, the following problems occur.

First, according to the configuration of FIG. 2 using the line comb filter, the current line signal outputted through the line comb filter, the signal before the first line and the signal after the one line are directly filtered by the band pass filter and the low pass filter, so that the vertical boundary In the cross talk (corss talk) component due to incomplete separation can be generated.

As a result, dot interference is generated and dot interference adversely affects image quality.

Second, according to the configuration of FIG. 1 using the line comb filter and the frame comb filter, the motion detector 3 has a low-pass filtered signal (i.e., residual luminance signal component) of the frame difference signal F, and thus the motion degree of the video signal. Since it is determined that the motion of the color signal and the motion of the high-frequency signal component has a disadvantage.

An object of the present invention is to provide a separation system of luminance signal and color signal which can eliminate the above disadvantages.

Another object of the present invention is to separate the luminance signal and the color signal using the line difference signal if the line correlation is good by the line correlation, and the luminance using the color signal extracted through the general filtering means if the line correlation is very poor. The present invention provides a system for separating a luminance signal and a color signal that separates a signal from a color signal.

Another object of the present invention is to separate the luminance signal and the color signal by using a combination of the frame difference signal and the color signal extracted through the general filtering means when the line correlation is poor due to the motion and line correlation of the composite video signal, When the line correlation is very good, the present invention provides a system for separating the luminance signal and the color signal by using a combination of the frame difference signal and the line difference signal.

In order to achieve the above object, according to the present invention, the line comb filtering means obtains a plurality of line difference signals between lines from an input composite video signal and outputs, as a line color signal, one having a good line correlation among the plurality of line difference signals by a control signal. .

The first filtering means extracts and outputs a color signal from the composite video signal. The line correlation detecting means detects the correlation between lines using a plurality of line difference signals and provides the detected signal as a control signal to the line comb filter means. The color signal detecting means detects the magnitude of the color signal output from the first filtering means. The switching means inputs the color signal of the first filtering means and the line color signal of the line com filtering means and selects one of the two input signals using the detection signal of the line correlation detection means and the output signal of the color signal detection means as control signals. 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 be synchronized with the generation of the output signal of the second filtering means. The subtraction means subtracts the output signal of the second filtering means from the output signal of the delay means and outputs it as the final luminance signal.

In addition, according to the present invention, the frame comb filtering means obtains one frame difference signal between adjacent frames from the input composite video signal and outputs the frame difference signal as a frame color signal.

The line filtering means obtains a plurality of line difference signals between lines from the composite video signal and outputs, as a line color signal, one having a good line correlation among the plurality of line difference signals by an external control signal.

The first filtering means extracts and outputs a color signal from the composite video signal.

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

The color signal detecting means detects the magnitude 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 filtering means, and outputs one of the input signals using the output signals of the line correlation detection means and the color signal detection means as control signals. . The motion detecting means detects the degree of motion of the video signal from the frame difference signal provided from the frame comb filtering means.

The motion signal generating means generates a predetermined motion coefficient in accordance with the output signal of the line correlation detecting means and the output signal of the motion detecting means.

The first calculating means calculates and outputs the output signal of the switching means and the motion coefficient, and the second calculating means calculates and outputs the subtraction of the motion coefficient from the output signal of the frame comb filtering means and the set reference value.

The adding means adds the output signals of the first and second calculating means, and the second filtering means filters the output signal of the adding means to output only the color signal components, and the third filtering means outputs the output signal of the adding means. It is filtered and output as the final color signal.

The delay means delays and outputs the composite video signal in synchronization with the generation of the output signal of the second filtering means, and the subtraction means subtracts the output signal of the second filtering means from the output signal of the delay means and returns the result as the final luminance signal. Output

The invention will be further clarified by the preferred embodiments described below.

4 is a block diagram showing a separation system of a luminance signal and a color signal using a line comb filter as a first embodiment of the present invention.

As shown in FIG. 4, the line comb filter selects and outputs one line difference signal having good line correlation as the line color signal LC from the input composite video signal CV by the line difference signal and the external control signal. 20, a band pass filter 21 for inputting a composite video signal CV together with the line comb filter 20 and extracting a color signal (center frequency fsc ± 0.5MHZ) from the line comb filter 20; A line correlation detector 22 and a band pass filter 21 for determining a line correlation using a plurality of supplied line difference signals LD and outputting a corresponding signal to the line comb filter 20 as an external control signal. The output signal of the color signal level detector 23 and the line comb filter 20 to the one input terminal d, and the output signal of the band pass filter 21 to the type force terminal (e) of the line correlation detector 22 Switch to an output signal of the signal level detector 23 as a switching control signal output by selecting one of two input signals (SW ₂₁₎ and a switch (SW ₂₁₎ after the output detecting the color signal to an output signal band filtering of A delayer for inputting the composite video signal CV together with the first filter 25 and the line comb filter 20 to be delayed for a predetermined time so as to be synchronized with the generation of the output signal of the first filter 25. (24) of the subtractor 26 and the switch SW ₂₁ for subtracting the output signal of the first filter 25 to the output signal of the delayer 24 and outputting the result as the final luminance signal Y; And a second filter 27 for outputting the filtered value as the final color signal C by band-filtering the output signal.

FIG. 5 shows one embodiment of the line comb filter 20 and the line correlation detector 22 in FIG.

In FIG. 5, the line comb filter 20 has two subtractors 53, 54, one adder (in addition to two line delays 51, 52 (e.g., two line memories may be used)). 55) and one multiplexer 60.

In addition, the line-correlation detector 22 has two absolute value calculators 57 and 59 of two low pass filters 56 and 58 and two having the set threshold values Vth ₂ and Vth ₃ respectively. It consists of comparators CP ₅₁ and CP ₅₂ .

In the present embodiment, the line comb filter is composed of two subtractors, a line delayer, and one adder, but may be configured with more subtractors, line delayers, and adders to obtain more line difference signals.

The line correlation detector can also consist of more lowpass filters, absolute value calculators and comparators.

FIG. 6 is a block diagram showing an embodiment of the color signal detector 23 in FIG. 4, and includes an absolute value calculator 23A and a comparator 23B having a threaded value Vth ₄ set at one terminal. .

The function of each element in FIGS. 5 and 6 will be clearly explained in their action described below.

FIG. 7 is a block diagram showing a system for separating luminance and color signals using a line comb filter and a frame comb filter together in a second embodiment of the present invention.

As shown in FIG. 7, the frame comb filter 31 which obtains the frame difference signal FD between adjacent frames from the input composite video signal CV and outputs the frame difference signal as the frame color signal FC; A line comb filter 32 which obtains a plurality of line difference signals LD from the input composite video signal CV and selects and outputs one line difference signal having excellent line correlation as the line color signal LC by an external control signal. And a plurality of line difference signals LD are supplied from the band pass filter 33 and the line comb filter 32 for extracting and outputting only the color signal components from the input composite video signal CV. The frame difference signal FD is supplied from the line correlation detector 34 and the frame comb filter 31 which outputs a signal corresponding to the result to the line comb filter 32 as an external control signal. Using video A motion detector 35 for detecting the degree of movement of the call, a color signal detector 36 for detecting the magnitude of the color signal output through the bandpass filter 33 and outputting a signal corresponding to the magnitude, and a line correlation detector ( A motion signal generator for generating a (0≤K≤1) motion coefficient (K) between 0 and 1 according to the degree of motion of the image signal output through the motion detector 35 of the line correlation signal output through 34) (39) and the output signal of the line comb filter 32 to the one input terminal g, the output signal of the band pass filter 33 to the type force terminal h, and the line correlation detector 34 and the color signal switch for selecting and outputting two sinhojung one control is input by the output signal of the detector (36), (SW ₃₁₎ and a switch (SW ₃₁₎ the motion coefficient output from the output signal and the movement signal generator 39 in the (K A multiplier 38 and a frame comb filter 31 for outputting An arithmetic operator 37 for multiplying the output signal FC and a value 1-K minus the motion coefficient K by one, and an adder 40 for adding the output signals of the arithmetic operator 37 and the operator 38. ), A first filter 41 for band-filtering the output signal of the adder 40 to output the final color signal C, and a second filter for outputting the output signal of the adder 40 by predetermined band filtering ( 41), from the composite video signal output from the delayer 42 and the delayer 42 for inputting the composite video signal CV and delaying the predetermined time to be synchronized with the output signal generation of the first filter 41; And a subtractor 43 for subtracting the color signal component output from the first filter 41 and outputting it as the final luminance signal Y.

4 and 7, when the system performs the band compression function, the band pass filters 21 and 33 and the first filters 25 and 41 which perform the band filtering function are high pass filters for the high pass filtering function. Can be replaced.

In addition, since the embodiment of the line correlation detector 34 and the color signal detector 36 of the line comb filter 32 is the same as that of the first embodiment shown in FIGS. 5 and 6, the description thereof will be omitted. Here, band compression refers to band compression that compresses a composite video signal having a larger frequency band as a signal of a lower frequency band. For example, band compression is called band compression to make only 5 mega band without damaging a signal having a band of 10 mega band, and band extension is to make a signal of a principle band reversely compressed.

FIG. 8 shows an embodiment of the motion detector 35 and the motion signal generator 39 of FIG. 7. The motion detector 35 is composed of a low pass filter 35A and an absolute value calculator 35B. The motion signal generator corresponds to the input signals among the data stored as a value between 0 and 1 according to the output signal of the input motion detector 35 and the output signal of the line correlation detector 34 as the motion coefficient K. It consists of a ROM for output.

The principle of the motion detector 35 and the motion signal generator 39 according to the present invention will be described below.

That is, the low pass filter 35A of FIG. 8 removes the color signal band (fse (3.58MHZ) ± 0.5MHZ) of the input frame difference signal and converts the remaining luminance signal to an absolute value.

If the composite video signal is still picture phase, the luminance signal level is the same as the signal between two frames (i.e., between the current frame signal and the frame signal before one frame or the frame signal after one frame). Because of the 180 ° phase difference, the frame difference signal will appear only as a color signal. When the signal is removed through the low pass filter 35A, the residual luminance signal DELTA Y does not appear, and the absolute value calculator 35B outputs almost zero values.

In contrast, when the composite video signal is a moving picture, the luminance signal phase of the two frames is different and the phase of the color signal is also different. Thus, in the frame difference signal, the luminance signal component and the component of the color signal will appear simultaneously. When these difference signals pass through the low pass filter 35A, the color signal component (fse ± 0.5MHZ) will be removed and only the components of the luminance signal will appear. At this time, the output of the absolute value calculator 35B has a value greater than zero. The output signal of the absolute value calculator 35B is input to the ROM, and the output signal of the line correlation detector 34 is also simultaneously input to the ROM.

The ROM selectively outputs one of a plurality of motion coefficients K stored in advance according to the input signals. The motion coefficient K is located in a section 0 ≦ K ≦ 1, and indicates that the closer the value of the motion coefficient K is to ″ 1 ″, the more severe the motion, and the closer to ″ 0 ″, the less motion. In addition, the principle of the line correlation detector 34 will be described as follows.

In FIG. 5, the line difference signal provided from the line comb filter 32 strictly includes the residual luminance signal DELTA Y as described above. Therefore, the line correlation detector 34 according to the present invention uses the low pass filters 56 and 58 to remove the color signal components, and converts only the residual luminance signal components ΔY into absolute values, and the magnitudes of the absolute values are large and small. Determine line correlation accordingly.

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

In other words, the closer the output of the line correlation detector 34 is to " 0 ", the more the line correlation is determined to be extremely good, and this is applied to the selection of the motion coefficient K. FIG.

In other words, even if the video signal is slightly motioned, when the line correlation is extremely good, the output signal of the line comb filter 32 is used.

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

First, in FIGS. 4 and 7, the composite video signal CV is a signal including the luminance signal Y and the chroma signal C, which is supplied to the line comb filter 20 or 32. The line delay unit 51 delays the composite video signal CV by one line and the line delay unit 52 delays the line by one line. This line comb filter 20 or 32 consists of two line delayers 51 and 52, two subtractors 53 and 54, one adder 55 and a multiplexer 60 as shown in FIG. The subtractor 53 subtracts the original video signal CV from the one line delayed composite video signal CV and the subtractor 54 subtracts the one line delayed video signal CV from the two line delayed composite video signal CV. Deserve it.

The output signals of the subtractors 53 and 54 are added by the adder 55 and output. The output signals of the subtracters 53 and 54 and the output signals of the adder 55 are supplied to the respective input terminals j, k and 1 of the multiplexer 60.

On the other hand, the output signal of the subtractor 53 and the output signal of the subtractor 54 are respectively removed through the low pass filter 65, the color signal components are removed to extract only the residual luminance signals? Y, and the residual luminance signal components (ΔY) are respectively converted into absolute values in the absolute value calculator 59 and then supplied to one input terminal of the comparator CP ₅₁ (CP ₅₂ ). Accordingly, the comparator CP ₅₁ and CP ₅₂ compare the input residual luminance signal with the set drain hold value Vth ₂ and Vth ₃ to generate and output a comparison signal S according thereto.

The comparison signal S is supplied to the multiplexer 60 again to serve 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 selects an input signal having a good line correlation as described above and outputs the output signal LC of the line comb filters 20 and 32.

In addition, the output signal S of the comparator CP ₅₂ (CP ₅₂ ) is supplied to the motion signal generator 39 of FIG. 7 so that the degree of line correlation is reflected in the generation of the motion coefficient K, and the switch ( SW ₃₁ is also supplied to cause the switch SW ₃₁ or SW ₂₁ to select the output signals of the band pass filters ₂₁ and 33 instead of the line comb filters _{20 and 32} when the line correlation is poor.

On the other hand, the color signal detectors 23 and 36 of the band pass filters 21 and 33 of Figs. 4 and 7 operate as follows.

As shown in FIG. 6, the color carrier carrier blood is extracted from the composite video signal CV by the band pass filters 21 and 33, and the extracted signal is converted into an absolute value in the absolute value calculator 23A. It is then input to the comparator 23B and compared with the thread hold value Vth ₄ set in the comparator 23B. As a result, the output signal of the comparator 23B is used as a signal for determining what level (i.e., magnitude) of the band-filtered color signal.

However, the output signal of the comparator 23B of FIG. 6 is supplied to the switch SW ₂₁ (SW ₃₁ ) together with the output signals of the line correlation detectors 22 and 34 so that the line correlation is extremely poor or the color carrier is When there is no at all, control to select the output signal of the band pass filter (21, 33).

As such, the signal selected by the switch SW ₂₁ (SW ₃₁ ) is synchronized with the output signal of the first filter 25 and 41 after filtering only signals of a desired frequency band by the first filter 25 and 41. And subtracted by the subtractor 43 together with the composite video signal CV output through the delayers 24 and 42.

The output signal of the subtractor 43 is the final luminance signal Y. The color signal selected by the switch SW ₂₁ (SW ₃₁ ), on the other hand, is band filtered through the second filter 27, 44 and output as the final color signal C. FIG.

Meanwhile, in FIG. 7, the frame color signal separated by the frame comb filter 31 and the line color signal separated by the line comb filter 32 and the band pass filter 33 are calculated at an appropriate ratio according to the degree of motion of the video signal. do.

That is, the motion detector 35 from the frame difference signal provided from the frame comb filter 21 determines the degree of motion of the video signal, and the output signal of the motion detector 35 is supplied to the motion signal generator 39.

On the other hand, the output signal of the line correlation detector 34 is also supplied to the motion signal generator 39. The motion signal generator 39 (ROM of FIG. 8) judges the amount of motion of the image signal detected by the motion detector 35 and the degree of line correlation detected through the line correlation detector 34, and stores the stored motion coefficient K. The corresponding ones of these are supplied to the calculators 37 and 38.

The calculators 37 and 38 are supplied with the motion coefficients K, and computed as follows, and their respective output signals are added to each other by the adder 40.

That is, when the FC: frame color signal (input signal of the operator 37, LC: line color signal (input signal of the operator 38, K: motion coefficient, V: output signal of the addition 40), the output of the adder 40 The signal can be expressed as in Equation (1).

[Equation 1]

V = (1-K) x FC + (K x LC) (0? … … … … … … … … … … … … (One)

The added signals are separated into the luminance signal Y and the chroma signal C through the first and second filters 41 and 44, respectively, as in FIG. 4. On the other hand, it may be necessary to compress the composite video signal CV in order to make it high resolution. Therefore, it is necessary to remove the interference component due to the band compression, in which case pre-filtering should be prioritized.

According to an embodiment of the present invention, motion detection and line correlation may be used to achieve pre-filtering for band compression and separation of luminance and color signals. That is, when band compression is required, a high pass filter having a predetermined frequency band may be used instead of the band pass filters 21 and 33 and the first filters 25 and 41 in FIGS. 4 and 7.

Therefore, pre-filtering is performed at the same time when the color signal is separated from the luminance signal without a separate pre-filter.

9 shows the composite video signal CV in a one-dimensional frequency spectrum. When the composite video signal CV of FIG. 9 is compressed in a frequency band as shown in FIG. 10 (a), the disturbance component can be removed.

FIG. 10 (a) shows the band-compressed composite video signal CV in one-dimensional frequency spectrum of horizontal and vertical planes fh-fv. That is, FIG. 10 (a) shows how the frequency spectrum overlaps by performing sub-nyquest sampling. FIG. 10B shows FIG. 9 in a two-dimensional frequency spectrum.

FIG. 11 shows a two-dimensional frequency spectrum when band compression is performed as shown in FIG. 10 (a) after only color signals are separated using line comb filters 20 and 32 by line correlation detection. In addition to the original signal Y, Apoint is represented by the spectrum of the compressible main fruit band.

According to FIG. 11, it can be seen that band compression can be performed without disturbing components.

FIG. 12 is a two-dimensional frequency spectrum of a horizontal-vertical (fh-fv) plane, which appears when only a luminance signal is compressed as shown in FIG. 10A after separating color signals using bandpass filters 21 and 33. to be.

Here, the display A is a spectrum represented by band compression.

FIG. 13 shows a time-vertical (ft-) representing a pre-filtering effect according to band compression when band-compression only luminance signals after separation of color signals using line comb filters 20 and 32 by detecting motion of an image signal. fv) is the two-dimensional frequency spectrum of the plane.

Finally, FIG. 14 is a two-dimensional spectrum of a time vertical (ft-fv) plane that exhibits a pre-filtering effect when band-compression only luminance signals after separation of color signals using frame comb filter 31 by motion detection.

In this way, the current line and one line detect the movement of the video signal from the line correlation and the frame difference signal of the before and after the one line, and separate the appropriate luminance signal (Y) and color signal (C), and at the same time separate filter It is possible to perform pre-filtering to remove disturbances in band compression without using.

In the above embodiment, the composite video signal is based on the NTSC system, but the PAL is also similar. Therefore, the composite video signal is not necessarily limited to the NTSC system. As described in detail above, the present invention detects the line correlation and the movement of the image signal in the separation of the luminance signal and the color signal, thereby selecting a color signal having a good line correlation, so as to select a high quality luminance signal from the composite image signal. Can be obtained by separating the color signal from the.

Therefore, when it is applied to a television receiver or a high-definition VCR, there is an effect that can obtain a good image.

In addition, when compressing the frequency band of the composite video signal, there is no need to perform pre-filtering separately to remove the interference component, which can simplify the configuration of a television receiver or a VCR, and compress and record and reproduce the frequency band of the signal. Applicable to the system.

Claims (22)

Line comb filtering and means for obtaining a plurality of line difference signals between lines from an input composite video signal CV and outputting, as a line color signal LC, one having a good line correlation among the plurality of line difference signals according to a control signal; First filtering means for extracting and outputting a color signal from the composite video signal (CV); Line correlation detection means for detecting the correlation between lines using the plurality of line difference signals LD and providing the detection signal as a control signal to the line comb filtering means, and detecting the magnitude of the color signal output from the first filtering means. Color signal detection means; A switching for inputting a color signal of the first filtering means and a line color signal of the line comb filtering means and selecting and outputting one of the two input signals using the detection signal of the line correlation detecting means and the output signal of the color signal detecting means as control signals; Way ; Second filtering means for outputting a color signal component by filtering an output signal of the switching means; Third filtering means for filtering the output signal of the switching means and outputting the final color signal; Delay means for delaying the composite video signal to be synchronized with generation of an output signal of a second filtering means; And a subtraction means for subtracting the output signal of the second filtering means from the output signal of the delay means and outputting the final signal as the final luminance signal. 2. The system of claim 1, wherein the first filtering means and the second filtering means are high pass filters when the separation system of the luminance signal and the color signal is a system for compressing a frequency band. The method of claim 1. The first filtering means and the third filtering means are all band pass filters. 2. The apparatus of claim 1, wherein the line comb filtering means comprises: a first line delayer (51) for delaying the composite video signal by one line; A second line delay 52 for delaying the output signal of the first line delay element by one line; A first subtractor 53 for subtracting the composite video signal from the output signal of the first line delay element; A second subtractor 54 for subtracting the output signal of the first line delay element from the output path of the second delay element; An adder 55 for adding the output signals of the first subtractor and the second subtractor; Line color signals are selected by inputting output signals of the first subtractor 53, the second subtractor 54, and the adder 55, respectively, and having a good line correlation by an external control signal outputted from the line correlation detecting means. And a multiplexer (60) for outputting as a separate system. 5. The apparatus as claimed in claim 4, wherein the line correlation detecting means comprises: a first low pass filter 56 for low color filtering the output signal of the first subtractor 53 to remove color signal components; A second low pass filter 58 for low-pass filtering the output signal of the second subtracter 54 to remove the color signal portion; A first absolute value calculator 57 for converting the residual luminance signal output from the first low pass filter 56 into an absolute value; A second absolute value calculator 59 for changing the residual luminance signal output from the second low pass filter 58 to an absolute value; A first comparator (CP ₅₁ ) for comparing the output signal of the first absolute value calculator 57 with the set thread hold value and providing the result as an external control signal to the multiplexer 60; And a second comparator CP ₅₂ for comparing the output signal of the second absolute value calculator 59 with the set thread hold value and providing the result as an external control signal to the multiplexer 60. Separation system of luminance signal and color signal. 5. The system of claim 4, wherein the line comb filtering means is further provided for performing the same function as the line retarder, the subtractor and the adder. 6. The separation system of luminance signal and color signal according to claim 5, wherein the line over-detection means is further provided for the low pass filter, the absolute value calculator and the comparator. 5. The system of claim 4, wherein the first and second line retarders (51, 52) are line memories. The color signal detecting means according to claim 1, further comprising: an absolute value calculator (57, 59) for obtaining an absolute value of the color signal output from the first filtering means; And a comparator (CP ₅₁ , CP ₅₂ ) for comparing the set hold value of the output signal of the absolute value calculator and outputs the result as a switching control signal of the switching means. system. Frame comb filtering means for obtaining one frame difference signal between adjacent frames from the input composite video signal CV and outputting the frame difference signal as a frame color signal; Line comb filtering means for obtaining a plurality of line difference signals between lines from the composite video signal (CV), and selecting one having a good line correlation among the plurality of line difference signals by an external control signal and outputting the line color signal as a line color signal; First filtering means for extracting and outputting a color signal from the composite video signal (CV); A line correlation detecting means for detecting a correlation with a line using a plurality of line difference signals of said line comb filtering means and supplying the detected signal as a control signal to said line comb filtering means: outputted from said first filtering means Color signal detection means for detecting the magnitude of the color signal; Inputting a line color signal detected by the line comb filtering means of the color signal output from the first filtering means, and selectively outputting one of the two input signals using the output signals of the line correlation detection means and the color signal detection means as control signals; Switching means; Motion detection means for detecting a motion degree of the video signal from the frame difference signal provided from the frame comb filtering means; Motion signal generating means for generating a predetermined motion coefficient in accordance with the output signal of the line correlation detecting means and the output signal of the motion detecting means; First calculation means for calculating and outputting the output signal of the switching means and the motion coefficient; Second calculation means for calculating and outputting a value obtained by subtracting the motion coefficient from an output signal of the frame comb filtering means and a set reference value; Addition means for adding output signals of the first and second calculation means; Second filtering means for filtering the output signal of the adding means to output only the color signal components; Third filtering means for filtering the output signal of said adding means and outputting it as a final color signal; Delay means for delaying the composite video signal to be synchronized with generation of an output signal of the second filtering means; And a subtraction means for subtracting the output signal of the second filtering means from the output signal of the delay means and outputting it as a final luminance signal. 11. The system of claim 10, wherein the first to third filtering means are band pass filters for passing only color signal components. 2. The system of claim 1, wherein the first filtering means and the second filtering means are high pass filters when the separation system of the luminance signal and the color signal is a system for compressing a frequency band. . 11. The apparatus of claim 10, wherein the line comb filtering means comprises two line delayers (51, 52) for delaying the composite video signal by one line in turn, and a first subtractor (1) which subtracts the line signal one line before the current line signal. 53); A second subtractor 54 which subtracts the current line signal from the line signal after the first pass; An adder 55 for adding the output signals of the first subtractor and the second subtractor; And a multiplexer 60 for inputting output signals of the first subtractor, the second subtractor, and the adder, respectively, and selecting one having good line correlation by an external control signal output from the line correlation detecting means and outputting the line signal as a line color signal. Separating system of the luminance signal and the color signal, characterized in that. 14. The apparatus of claim 13, wherein the line correlation detecting means comprises: a first low pass filter (56) for low color filtering the output signal of the first subtractor to remove color signal components; A second low pass filter 58 for low-pass filtering the output signal of the second subtractor to remove color signal components; A first absolute value calculator (57) for converting the residual luminance signal output from the first low pass filter (56) and the second low pass filter (58) into an absolute value; A second absolute value calculator 59 for changing the residual luminance signal output from the second low pass filter to an absolute value; A first comparator (CP ₅₁ ) for comparing the output signal of the first absolute value calculator with the set threshold value and providing the result as an external control signal to the multiplexer; And a second comparator (CP ₅₂ ) which compares the output signal of the second absolute value calculator with the set dread hold value and provides the result as an external control signal to the multitude tuner (60). Color signal separation system. The system of claim 13, wherein the line comb filtering means is further provided for performing the same function of the line delay, the subtractor and the adder. 15. The system of claim 14, wherein the line correlation detection means further comprises a low pass filter, an absolute value calculator and a comparator for performing the same function. 15. The system of claim 13, wherein the first and second line delays are line memories. 11. The color signal detecting means according to claim 10, further comprising: an absolute value calculator (57, 59) for obtaining an absolute value of the color signal output from the first filtering means; And a comparator (CP ₅₁ , CP ₅₂ ) for comparing the output signal of the absolute value calculator and the set thread hold value and outputs the result as a switching control signal of the switching means. system. 11. The apparatus of claim 10, wherein the motion detecting means comprises: a low pass filter (35A) for low-pass filtering the frame difference signal provided from the frame comb filtering means to remove color signal components; And an absolute value calculator (35B) for obtaining an absolute value of the residual luminance signal component which is an output signal of the low pass filter. 11. The apparatus of claim 10, wherein the motion signal generating means stores a plurality of motion coefficient values, and selects and outputs a corresponding one of the plurality of motion coefficients according to output signals of the line correlation detecting means and the motion detecting means. Separating system of luminance signal and color signal. 21. The system of claim 20, wherein the memory is a ROM. 11. The method of claim 10, wherein when the reference value of the second operator is 1 and 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 is a frame And a luminance signal and a color signal separated by multiplying the output signal of the comb filtering means by the 1-motion coefficient K.