KR19980079064A - A luminance and color separation method for correcting deterioration of vertical resolution and a luminance and color separation circuit for performing the same - Google Patents

Abstract

Disclosed are a luminance and color signal separation method and a separation circuit that can separate luminance and color signals from a composite video video signal without crosstalk and improve image quality by compensating for high frequency portions having a predetermined vertical frequency or more. It is. A first luminance signal, a second luminance signal, and a color signal are respectively separated from the composite video signal, and a second luminance signal and a second color signal are separated from the second luminance and color signals. The second luminance signal is multiplied by the gain α to generate an α amplified second luminance signal, and then the phase first luminance signal and the α amplified second luminance signal are calculated. In the case where the vertical frequency of the luminance signal is high, the image quality may be improved by correcting this.

Description

A luminance and color separation method for correcting deterioration of vertical resolution and a luminance and color separation circuit for performing the same

The present invention relates to a method for separating the luminance and color signals of a television receiver and a luminance and color separation circuit for performing the same. More specifically, the present invention provides a method for separating luminance and color signals for improving the image quality of the vertical part by adjusting a frequency corresponding to the vertical part of the luminance signal to reduce attenuation by the high frequency region of the vertical frequency of the luminance signal. It relates to a luminance and color separation circuit for performing.

In general, the human eye is known that color information such as hue and saturation does not need to be as detailed as the information necessary for luminance in the image quality and image of the same sharpness. Therefore, the largest frequency band is allocated to the luminance signal in the frequency band of the television. On the other hand, for hue and saturation that do not correspond to the amount of change in luminance, the human eye should have 1/10 to 1/3 of the resolution required for brightness.

Color signals modulated as color subcarriers by the above properties are put in a band much narrower than the luminance signal band. For example, in the NTSC system, an I signal component of a color signal modulated as a color subcarrier uses a 1.3 MHz band, and a Q signal component uses a 0.5 MHz band. Providing a wider band for the I signal component compared to the Q signal component of the color signal is because the I signal is better for color resolution.

Since the frequency of the color subcarrier is 3.58 MHz, the modulated color signal is interleaved on the high frequency sideband of the luminance signal to generate a composite image signal. The comb filter method is used to minimize the attenuation of the luminance signal and the interference by the luminance signal of the color signal when the luminance signal and the color signal interleaved with the luminance signal are separated from the composite image signal.

1 is a block diagram illustrating an example of a conventional luminance and color signal separation circuit. In FIG. 1, the luminance and color separation circuit 100 includes a retarder 110, a low pass filter 120, a subtractor 130, a comb filter 140, and an adder 150. The delayer 110 delays the input composite video signal 111 by a predetermined time and then provides the delayed composite video signal 112 to the subtractor 130. The low pass filter 120 passes only the composite image signals 122 in the frequency range of 3 MHz or less from the input composite image signal 111 and passes only the low pass composite image signals 122 to pass the low pass. The complex image signal 122 is provided to the subtractor 130 and the adder 150. The composite video signal passing through the low pass filter 120 is a frequency signal of only a luminance component.

The subtractor 130 subtracts a frequency signal of only a luminance component within a frequency range of 3 MHz or less input from the low pass filter 120 from the composite image signal 111 input from the delay unit 110 to display luminance and luminance. The 3MHz or more composite video signal of which color signals are interleaved is generated, and the generated 3MHz or more composite video signal is provided to the comb filter 140. The comb filter 140 comb-filters the input interleaved composite video signal of 3 MHz or more to generate a color signal C and a luminance signal 411 of 3 MHz or more to output the generated color signal C. A luminance signal 411 of 3 MHz or higher is provided to the adder 150. Then, the adder 150 adds the luminance signal 122 from the low pass filter 120 and the luminance signal 411 from the comb filter 140 to generate an original luminance signal having a high luminance component. It generates (Y) and outputs it.

However, in the operation of the comb filter, the vertical phase relationship between the luminance signal and the color signal has a high degree of vertical correlation, for example, in the image having no change between lines, without high crosstalk on the luminance signal of the color signal. The luminance signal of the frequency band can be saved, but if the image is a moving picture, the vertical correlation of the picture deviates. Therefore, in this case, the luminance signal output from the comb filter results in a high frequency component of the luminance signal flowing into the color signal component to generate a crosstalk phenomenon. And, if there is a high-frequency portion at a certain vertical frequency or more it can not be compensated.

Accordingly, a first object of the present invention is to provide a luminance and color signal that can be separated from a composite video signal without crosstalk, and to compensate for the presence of a high frequency portion of a predetermined vertical frequency. It is to provide a color signal separation method.

It is a second object of the present invention to provide a luminance and color separation circuit which is particularly suitable for performing the above-described luminance and color signal separation method.

1 is a block diagram illustrating an example of a conventional luminance and color signal separation circuit.

2 is a block diagram illustrating a luminance and color signal separation circuit according to a first embodiment of the present invention.

3 is a block diagram illustrating a luminance and color signal separation circuit according to a second exemplary embodiment of the present invention.

Explanation of symbols on the main parts of the drawing

111, 202: Composite video signal 120, 310, 810: Low pass filter

110, 210: 1H delay

130, 230, 320, 820: Subtractor

140, 200, 700: comb filter

150, 220, 501, 1001: adder

401: α amplifier 901: gain controller

In order to realize the first object of the present invention, the present invention comprises the steps of: (a) separating the first luminance signal and the second luminance and color signals from the composite video signal; (b) separating a second luminance signal and a second color signal from the second luminance and color signals; (c) multiplying the second luminance signal by a gain α to generate an α amplified second luminance signal; (d) providing a luminance and color separation method that compensates for a high frequency portion of a horizontal frequency consisting of calculating the first luminance signal and an amplified second luminance signal.

According to the method, the composite video video signal input through the input terminal is separated from the first luminance signal and the second luminance and color signals by step (a). The second luminance and color signals separated from the composite video signal by step (a) are separated into a second luminance signal and a second color signal by step (b). The second luminance signal separated by step (b) is multiplied by the gain α to generate an α amplified second luminance signal. After the sum of the first luminance signal separated by step (a) and the second luminance signal separated by step (b), the amplified second luminance signal generated by step (c) is calculated to obtain luminance. If the vertical frequency of the signal is high range, it can be corrected to improve the image quality.

In order to realize the second object of the present invention described above, the present invention provides a video signal processing apparatus comprising: first signal separation means for detecting a video signal interleaved with a first brightness signal and a second brightness and color signal from a composite video signal; Second signal separation means for separating a second luminance signal and a second color signal from the second luminance and color signals; Second signal amplifying means for amplifying the second luminance signal by α; A luminance and color signal separation circuit comprising a luminance signal output means for calculating the first luminance signal and the amplified second luminance signal and outputting a luminance signal is provided.

According to the above configuration, the composite video video signal input through the input terminal is separated into a first luminance signal and a second luminance and color signal by a comb filter which is a first signal separation means. The first luminance signal is a luminance signal Y _{L in} which the vertical frequency is low, and the second luminance signal is a luminance signal Y _{H in} which the vertical frequency is high. The vertical resolution can be increased by correcting the second luminance signal whose vertical frequency is high. However, since the second luminance signal and the second color signal are interleaved in the second luminance and color signals separated by the first signal separation means, frequency correction should be performed only for the second luminance signal. Thus, the second signal separating means separates the second luminance signal and the color signal from the second luminance signal and the color signal. The second signal amplifying means provides an amplified second luminance signal amplified by multiplying the gain α by the second signal separated by the second signal separating means to the adder of the luminance signal output unit. The luminance signal output means may calculate the second luminance signal amplified by the result of the calculation of the first luminance signal and the second luminance signal to correct the case where the vertical frequency of the luminance signal is high, thereby improving image quality.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

Example 1

2 is a block diagram illustrating a luminance and color signal separation circuit according to a first embodiment of the present invention. The luminance and color signal separation circuit 600 includes a first signal separation unit 200, a second signal separation unit 300, a second signal amplifier 400, and a luminance signal output unit 500.

The first signal separator 200 includes a comb filter including a delayer 210, a first adder 220, and a first subtractor 230.

The retarder 210 provides the first adder 220 and the first subtractor 230 with a luminance signal 212 obtained by delaying the composite video signal 202 input from the input terminal 201 by 1H. The first adder 220 adds the composite video signal 202 input from the input terminal 201 and the 1H delayed luminance signal 212 output from the delayer 210 to generate a first luminance signal having a low vertical frequency. Output (222). The first subtractor 230 subtracts the 1H delayed luminance signal 212 output from the delayer 210 from the composite image signal 202 input from the input terminal 201 and the second luminance having a vertical frequency of high frequency. A second luminance and color signal 232 interleaved with the color signal is output.

The second signal separator 300 includes a 3 MHz low pass filter (LPF) 310, a second subtractor 320, and a second adder 330.

The low pass filter 310 is formed from the second luminance and color signals Y _H + C and 232 output from the first subtracter 230 of the comb filter 200, which is the first signal separation unit 200. Generates two luminance signals Y _H , 312. The second luminance and color signal 232 is a signal in which the color signal C of 3 MHz or more and the luminance signal Y _H of 0 to 3 MHz are interleaved, and the second luminance and color signal using a 3 MHz low pass filter. The second luminance signal Y _H 312 is separated from 232. The separated second luminance signal is provided to the second adder 330, the second subtractor 320, and the second signal amplifier 400.

The second subtractor 320 subtracts the second luminance signal 312 output from the low pass filter 310 from the second luminance and color signal 232 provided from the first subtractor 230 to generate a color signal ( Output C).

The second subtractor 330 may include first luminance signals Y _L and 222 provided from the first adder 220 of the first signal separator 200 and second luminance signals provided from the 3 MHz low pass filter 310. (Y _H, 312), an addition, and outputs the luminance signal 332 times also to the signal output section 500. The luminance signal 332 is a luminance signal Y separated from the composite image 202 in which the first luminance signals Y _L and 222 and the second luminance signals Y _H and 312 are added. The luminance signal output by the second subtractor 330 is as follows.

The second signal amplifier 400 is composed of an α amplifier 401. The α amplifier 401 amplifies the second luminance signals Y _H and 312 output from the low pass filter 310 of the second signal separation unit 300 by α, thereby amplifying the second luminance signals α Y _H. , 402 is output to the third adder of the luminance signal output unit 500. The gain α of the α amplifier is The correction value can be set as a value between or adjusted through control.

The luminance signal output unit 500 includes a third adder 501. The third adder 501 is configured to output the first luminance signal Y _L and 222 output from the first adder of the first signal separation unit 200 and the second output signal from the low pass filter of the second signal separation unit 300. The vertical frequency is corrected by adding the second luminance signal 402 amplified by the α amplifier 400 of the second signal amplifier 400 to the luminance signal 322 to which the luminance signals Y _H and 312 are added. Output the luminance signal Y '.

A luminance signal Y ′ having a horizontal frequency corrected from the third adder 500 of the luminance signal output unit 500 is as follows.

Therefore, according to the above configuration, when the luminance signal is separated from the composite video signal, the signal having the luminance and color signals interleaved is extracted by the low pass filter, and the luminance signal of the high band is added to the luminance signal of the low band. The vertical frequency can be corrected by adding the high-band luminance signal to the amplified signal. This is because the vertical frequency correction of a signal obtained by amplifying a high-band luminance signal after separating the color signal in the high frequency region from the luminance and the color signal in advance, thereby generating a cross in which the high frequency component of the luminance signal is introduced into the color signal component in the moving image. The torque phenomenon can be prevented.

Example 2

3 is a block diagram illustrating a luminance and color signal separation circuit according to a second exemplary embodiment of the present invention. The luminance and color signal separation circuit 1100 includes a comb filter 700 which is a first signal separation unit, a second signal separation unit 800, a gain control unit 900, and a luminance signal output unit 1000.

The comb filter 700 of the first signal separator has the same configuration as the comb filter of the first signal separator 200 according to the first embodiment. Therefore, detailed description thereof will be omitted.

The second signal separator 800 may include a 3 MHz low pass filter (LPF) identical to the low pass filter 310 and the second subtractor 320 of the second signal separator 300 according to the exemplary embodiment. , 810 and a first subtractor 820. The low pass filter 810 generates the second luminance signals Y _H and 812 from the second luminance and color signals Y _H + C and 704 output from the comb filter 700 as the first signal separator. do. The first luminance and color signal 704 is a signal in which the color signal C of 3 MHz or more and the luminance signal Y _H of 0 to 3 MHz are interleaved, and the second luminance and color signal using a 3 MHz low pass filter. The second luminance signal Y _H , 812 is separated from 704. The separated second luminance signal 812 is provided to the gain control unit 900 and the subtractor 820.

The subtractor 820 subtracts the second luminance signal 812 output from the low pass filter 810 from the second luminance and color signal 704 provided from the comb filter 700 to subtract the color signal C. Output

The gain controller 910 of the gain control unit 900 amplifies the second luminance signal 812 output from the 3 MHz low pass filter 810 of the second signal separation unit 800 by α, thereby increasing the luminance signal output unit. Output to (1000). Gain α of the gain controller It is possible to smooth the signal in the vertical direction by correcting it as a value in between.

The luminance signal output unit 1000 has the same configuration as the luminance signal output unit 500 according to the first embodiment. The adder 1001 of the luminance signal output unit 1000 outputs the first luminance signals Y _L and 702 output from the first signal separator 700 and the low pass filter of the second signal separator 810. The second luminance signal 902 amplified by the second luminance signals Y _H and 812 which have been amplified is added to output the luminance signal Y 'whose vertical frequency is corrected.

The luminance signal Y 'whose horizontal frequency is output from the adder 1001 of the luminance signal output unit 1000 is corrected as follows.

Therefore, according to the above configuration, when the luminance signal is separated from the composite video signal as in the first embodiment of the present invention, the high-band luminance signal is extracted by a low pass filter from the interleaved luminance and color signals. After adding with the low-band luminance signal, the vertical frequency can be corrected by adding the high-band luminance signal with the amplified signal. This is because the vertical frequency correction of a signal obtained by amplifying a high-band luminance signal after separating the color signal in the high frequency region from the luminance and the color signal in advance, thereby generating a cross in which the high frequency component of the luminance signal is introduced into the color signal component in the moving image. The torque phenomenon can be prevented.

The configuration is different from the embodiment in that the gain α of the gain controller It is possible to smooth the signal in the vertical direction by correcting it as a value in between.

As described above, the present invention provides a luminance and color signal separation and method for separating the luminance signal and the color signal from the composite video signal without crosstalk.

Although the present invention has been described in detail with reference to one embodiment and another embodiment, the present invention is not limited thereto, and variations and improvements can be made without departing from the ordinary knowledge of those skilled in the art.

Claims (13)

(a) separating an interleaved video signal from the composite video signal, wherein the first luminance signal and the second luminance and color signals are interleaved; (b) dividing the video signal in which the second luminance and color signals separated by step (a) are interleaved into a second luminance and a second color signal, respectively; (c) amplifying the second luminance signal separated by step (b); And and (d) calculating the first luminance signal separated by step (a) and the second luminance signal amplified by step (c). The method of claim 1, wherein step (a) (a-1) detecting a low luminance first luminance signal by adding an input composite video signal and a signal obtained by delaying the composite video signal by 1H; And (a-2) subtracting a signal obtained by delaying the composite video signal by 1H from the input composite video signal to detect the interleaved second luminance and color signals. The method of claim 2, wherein step (b) (b-1) low-pass filtering the second luminance and color signals separated by step (a-2) to separate the second luminance signal; (b-2) subtracting the second luminance signal separated by the step (b-1) from the second luminance and color signal separated by the step (a-2) to separate the color signal; And (b-3) adding the first luminance signal separated by step (a-1) and the second luminance signal separated by step (b-1) and outputting a luminance signal. A luminance and color signal separation method. 4. The method of claim 3, wherein step (c) comprises amplifying the second luminance signal low-pass filtered by step (b-1). 4. The method of claim 3, wherein the step (d) comprises calculating and outputting the luminance signal added by the step (b-3) and the second luminance signal amplified by the step (c). A luminance and color signal separation method. The method of claim 2, wherein step (b) (b-1) low-pass filtering the second luminance and color signals separated by step (a-2) to separate the second luminance signal; And (b-2) subtracting the second luminance signal separated by the step (b-1) from the second luminance and color signal separated by the step (a-2) to separate the color signal. Method for separating luminance and color signals, characterized in that. 7. The method of claim 6, wherein step (d) comprises calculating and outputting the first luminance signal separated by step (a) and the second luminance signal amplified by step (c). A luminance and color signal separation method. First luminance signal separating means (200, 700) for separating the first luminance signal and the second luminance and color signal into the interleaved image signal from the composite image signal, respectively; Second signal separation means (300, 800) for separating the video signal interleaved with the second luminance and color signals into second luminance and color signals, respectively; Second signal amplifying means (400, 900) for amplifying a second luminance signal separated from the second signal separating means (300, 800); And The result of calculating the first luminance signal separated by the first luminance signal separating means 200 and 700 and the second luminance signal separated by the second luminance signal separating means is obtained from the second signal amplifying means 400 and 900. And luminance signal output means (500, 1000) for calculating the output amplified second luminance signal and outputting the luminance signal. The method of claim 8, wherein the first luminance signal separating means (200, 700) A first delayer (210) for delaying the input composite video signal for a predetermined time; A first adder 220 for adding the input composite video signal 202 and the signal delayed by 1H from the first delayer 220; And And a first subtractor (230) for subtracting the 1H delayed signal from the first delayer (220) from the input composite video signal (202). The method of claim 8, wherein the second signal separation means 300 passes low pass through the second luminance and color signals 232 output from the first adder 230 of the first signal separation means 200. A 3 MHz low pass filter 310 for separating the luminance signal; For subtracting the second luminance signal 312 passing through the low pass filter 310 from the second luminance and color signal 232 output from the first subtractor 230 of the first signal separation means 200. A second subtractor 320; And A second adder for adding and outputting a first luminance signal 222 output from the first adder 220 of the first signal separating means 200 and a second luminance signal output from the low pass filter 310. 330 is a luminance and color signal separation circuit, characterized in that. 11. The method of claim 10, wherein the luminance signal output means 500 is amplified by the luminance signal 332 output from the second adder 330 of the second luminance signal separation means 300 and the second signal amplification means. And a third adder (501) for adding the second luminance signal (402). The method of claim 8, wherein the second signal separating means 800 A 3 MHz low pass filter 810 for low-passing the second luminance and color signal 704 output to the first signal separation means 700 to separate the second luminance signal; And And a subtractor 820 for subtracting the second luminance signal 812 passing through the low pass filter 810 from the second luminance and color signal 704 output from the first signal separation means 200. A luminance and color signal separation circuit, characterized in that. The method of claim 12, wherein the luminance signal output means 1000 is the luminance signal 702 output from the first luminance signal separation means 700 and the amplified second luminance signal 902 output from the signal amplification means (900) And an adder (1001) for adding < RTI ID = 0.0 >