KR0141129B1 - Apparatus for separating chroma signal - Google Patents

Abstract

The present invention relates to a color signal separation device of a color image processing device, and more particularly, to a color signal separation device capable of using a PAL two-line comb filter and an NTSC three-line comb filter.

The color signal separator provides NTSC / PAL combined color signal separator to simplify the hardware configuration.

Description

Color signal separator

1 is a block diagram of an NTSC three-line color signal separation device.

2 is a diagram showing an exemplary image.

3A-3C are diagrams showing a horizontal scan line input to the vertical correlator shown in FIG.

4A-4D are diagrams showing waveforms of respective parts in the color signal separation apparatus using the three-line type combi filter for showing the operation of the vertical correlator shown in FIG.

5 is a view showing an example of the color signal separation device of the present invention.

6A-6C show horizontal scanning lines input to the color signal separation apparatus of FIG.

7A-7D show waveforms of respective parts in the color signal separation device of the present invention shown in FIG.

8 is another embodiment of the color signal separation apparatus of the present invention.

9 is another embodiment of the separation device of the present invention.

The present invention relates to a color signal separation device of a color image processing device, and more particularly, to a color signal separation device capable of using a PAL two-line comb filter and an NTSC three-line comb filter.

Current color television systems use a composite video signal in which a color signal (carrier color signal) balanced by color subcarriers is superimposed on a luminance signal. For this reason, the receiving side requires a device for separating the color signals superimposed on the luminance signal.

In the detailed method of superimposing a color signal on a luminance signal, the NTSC method has a relationship in which the phase of the luminance signal between two adjacent horizontal scan lines is the same and the phase of the color signal is inverted (phase difference of 180 degrees).

However, in the PAL method, unlike the NTSC method, a phase difference of 90 degrees is maintained in color signals between adjacent horizontal scan lines.

Therefore, in the PAL system, the phase of the carrier color signal is in phase every 4H. Therefore, a color signal separation apparatus capable of using both broadcasting systems is required in an image processing apparatus that uses both NTSC / PAL.

An object of the present invention is to provide a color signal separation device that can share a vertical correlator applied to a three-line comb filter in a PAL type color signal processing device.

Another object of the present invention is to provide a color signal separation apparatus applicable to both PAL and NTSC.

A color signal separation apparatus of the present invention for achieving the above object is in the device for separating the color signal from the PAL video signal including the color signal modulated by the color carrier,

A delayer for introducing the PAL video signal and delaying the PAL video signal by two horizontal scanning periods according to the PAL method;

An inverter for introducing an output of the retarder and outputting the phase inverted;

A first zero level signal generator for generating a color signal modulated by a zero level chroma signal;

A first low voltage detector configured to input the output of the video signal and the inverter and to select and output a signal having a low voltage level among them;

A second low voltage detector configured to input an output of the inverter and an output of the first zero level signal generator, and select and output a signal having a low voltage level among them;

A first high voltage detector configured to input the output of the video signal and the first inverter and to select and output a signal having a high voltage level among them;

A second high voltage detector configured to input an output of the inverter and an output of the first zero level signal generator and to select and output a signal having a high voltage level among them;

A second zero level signal generator for generating a color signal modulated by a zero level chroma signal;

A third high voltage detector configured to input an output of the first low voltage detector, an output of the second low voltage detector, and an output of the second zero level signal generator, and select and output a signal having a high voltage level among them;

A third low voltage detector configured to input an output of the first high voltage detector, an output of the second high voltage detector, and an output of the second zero level signal generator, and select and output a signal having a low voltage level among them; And

And an adder for introducing the output of the third high voltage detector and the output of the third low voltage detector and adding them to output a color signal separated from the image signal.

In another aspect of the present invention, there is provided a color signal separating apparatus for separating color signals from NTSC video signals or PAL video signals including color signals modulated by a color carrier.

A first delay unit for introducing an NTSC video signal and delaying the same by one horizontal syringe according to the NTSC system;

A first inverter which inputs the output of the first delay and inverts the output of the first delay;

A second delayer for introducing the output of the first delayer and delaying the output of the first delayer by one horizontal syringe according to the NTSC method;

A third delayer for introducing the PAL video signal and delaying the PAL video signal by two horizontal syringes according to the PAL method;

A second inverter that inputs the output of the third delay and inverts the output of the third delay;

A first zero level signal generator for generating a color signal modulated by a zero level chroma signal;

A first switch for selecting and outputting one of the PAL video signal and the NTSC video signal in response to an NTSC / PAL selection signal applied thereto;

A second switch for selecting and outputting one of an output of the second inverter and an output of the first inverter in response to an NTSC / PAL selection signal applied thereto;

A third switch for selecting and outputting one of an output of the first zero level signal generator and an output of the second delay unit in response to an NTSC / PAL selection signal applied thereto;

A first low voltage detector for introducing an output of the first switch and an output of the second switch and selecting and outputting a signal having a low voltage level among them;

A second low voltage detector for introducing an output of the second switch and an output of the third switch, and selecting and outputting a signal having a low voltage level among them;

A first high voltage detector for introducing an output of the first switch and an output of the second switch, and selecting and outputting a signal having a high voltage level among them;

A second high voltage detector for introducing an output of the second switch and an output of the third switch, and selecting and outputting a signal having a high voltage level among them;

A second zero level signal generator for generating a color signal modulated by a zero level chroma signal;

A third high voltage detector configured to input an output of the first low voltage detector, an output of the second low voltage detector, and an output of the second zero level signal generator, and select and output a signal having a high voltage level among them;

A third low voltage detector configured to input an output of the first high voltage detector, an output of the second high voltage detector, and an output of the second zero level signal generator, and select and output a signal having a low voltage level among them; And

And an adder for introducing the output of the third high voltage detector and the output of the third low voltage detector and adding them to output a color signal separated from the image signal.

The color signal separation device which achieves the object of the present invention provides a PAL type color signal separation device that can share the vertical correlator used in the three-line comb filter, and obtains a color signal with reduced vertical resolution and horizontal DOT interference of the color signal. Can be.

The color signal separation device which achieves another object of the present invention can simplify the configuration of hardware by providing the NTSC / PAL combined color signal separation device. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Color signal separation device suitable for NTSC type can be roughly divided into two-line comb filter and three-line comb filter. The two-line comb filter includes one retarder and an inverter and a vertical correlator. The two-line comb filter includes one retarder and an inverter and a vertical correlator. The two-line comb filter performs color signal separation by delaying a horizontal scanning line by one horizontal syringe slot (1H), inverting its phase, and adding it to the original horizontal scanning line. Since the two-line comb filter is a method of subtracting color signals included in two horizontal scan lines, it is inevitable that color smears occur in the vertical direction.

An improvement of the two-line comb filter is a three-line comb filter. The three-line comb filter includes two 1H delays, one inverter and a vertical correlator. The three-line comb filter separates color signals by using the correlation between a horizontal scan line and horizontal scan lines adjacent to the front and rear thereof, thereby increasing the vertical resolution and reducing the horizontal DOT interference and cross color.

1 is a view showing a three-line comb filter of the NTSC system.

The three-line comb filter shown in FIG. 1 includes the first and second retarders 1 and 2, the first inverter 3, the first and second and third band pass filters 4, 5, 6 and the vertical correlator. Includes 15.

The first and second delayers have a delay characteristic of 1H. The first, second, and third band pass filters have a frequency of the color subcarrier (3.58 MHz in the case of NTSC) as a pass frequency. Vertical correlator 14 includes first and second lower voltage detection circuits (hereinafter referred to as MIN circuits), 7 and 8 and 12, and first and second and third high voltage detection circuits (Higher Voltage Detecting Circuits). 9 and 10 and 11, adder 13, and zero-level signal generator 14.

The high voltage detection circuits 7, 8, and 12 detect the highest voltage between the input signals and output the voltage. The low voltage detection circuits 9, 10 and 11 detect the lowest voltage between the input signals and output the voltage.

The zero level signal generator 14 generates a color subcarrier signal modulated by a zero level color signal. In the current color television system, color carriers modulated with color signals are transmitted superimposed on luminance signals.

The band carrier filter has a band pass frequency corresponding to the frequency of the color carrier in the signal received at the receiver to separate the color carriers superimposed on the luminance signal and modulated by the transmitted color signal.

The color carriers modulated by the color signal superimposed on the luminance signal are changed according to the change in the potential of the luminance signal, but the color carriers modulated by the color signal through the bandpass filter oscillate up and down with a constant potential as the center value. It becomes a sine wave (only considering the color size). In other words, when the color signal is present, the result is a sine wave having a wave height according to the magnitude of the color signal. When the color signal does not exist, the constant potential is maintained. Normally, this constant potential is the earth voltage. Therefore, the zero-level signal generator 14 preferably has a constant voltage power source, but may be of the type that is grounded directly or through a resistor or the like.

The operation of the three-line comb filter shown in FIG. 1 will be described with reference to FIGS. 2, 3A-3D and 4A-4D. The input video signal a is supplied to the first delay unit 1 and the first band pass filter 4. The delayed signal b output from the first delay unit 1 is supplied to the first inverter 3 and the second delay unit 2.

The signal d inverted from the first inverter 3 is supplied to the second band pass filter 5. The delayed signal c from the second delay unit 2 is supplied to the third bandpass filter 6.

The bandpassed signal e in the first bandpass filter 4 is supplied to the first MIN circuit 7 and the first MAX circuit 9. The bandpassed signal f in the second bandpass filter 5 is supplied to the first second MIN circuits 7 and 8 and the first second MAX circuits 9 and 10. The bandpassed signal g in the third bandpass filter 6 is applied to the second MAX circuit 10.

In the first MIN circuit 7, the first low voltage signal h between the signals e and f is generated, and the first low voltage signal f is supplied to the third MAX circuit 11.

In the second MIN circuit 8, a second low voltage signal I is generated between the signals f and g, and the second low voltage signal g is supplied to the third MAX circuit 11.

In the first MAX circuit 9, the first high voltage signal j between the signals e and f is generated and the first voltage signal j is supplied to the second MIN circuit 12.

In the second MAX circuit 10, a second high voltage signal k between signals f and g is generated and the second high voltage k is supplied to the second MIN circuit 12. Meanwhile, the zero level signal 1 of the zero level signal generator 14 is supplied to the third MAX circuit 11 and the third MIN circuit 12.

In the third MAX circuit 11, a third high voltage signal m between the first low voltage signal h, the second low voltage signal i, and the zero level signal 1 is generated, and the third high voltage signal m is supplied to the adder 13. In the third MIN circuit 12, a third low voltage signal n between the first high voltage signal j, the second high voltage signal k, and the zero level signal 1 is generated, and the third low voltage signal n is supplied to the adder 13. In the adder 13, a signal o in which the third low voltage signal m and the third low voltage signal n are added is generated, and the added signal o is output as the output of the three-line comb filter, that is, as a separate color signal.

The operation of the color signal separation device shown in FIG. 1 will be described in detail with reference to FIGS. 2, 3A- 3D and 4A-4D.

First, the color signal separation operation in the vertical decorrelating portion will be described.

It is assumed that a carrier color signal having an original image as shown in FIG. 2 is applied to the color signal separation apparatus of FIG. The image consists of the uncolored part (A) at the top, the colored part (C) at the center and the uncolored part (E) at the bottom. The symbol D represents the first horizontal scan line of the uncolored portion at the bottom.

When the signal corresponding to the portion B is output from the first delay unit 1, the horizontal scan line signals p, q, and r sequentially on the screen are displayed as shown in FIG. 3A. In this case, the signals d, e, f, g, h, i, j, k, l, m, n and the signal o from which the cross colors are removed in the color signal separator of FIG. 1 are shown in FIG. 4A.

When the signal corresponding to the portion D is output from the first delay unit 1, the sequential horizontal scan line signals p, q and r on the screen are displayed as shown in FIG. 3B. In this case, the signals d, e, f, g, h, i, j, k, l, m, n and o in the color signal separator of FIG. 1 are shown in FIG. 4A. In the signal o, it can be seen that no color signal is output.

In the case where the sequential signals p, q and r have the same color, all signals e, f, g, h, i, j, k, l, m, n and o having the same color are shown in FIG. 4C. Is shown on. You also get a signal o that all the signals have no color.

An operation of removing the luminance signal of the component corresponding to the frequency of the color subcarrier will be described. Since there is no phase difference of the luminance signal between adjacent horizontal scan lines, the sequential horizontal scan signal d, e, f, g, h, i, j, k, l, m, n and the signal o whose cross color has been removed are It is shown in Figure 4D.

As described above, the color signal separation apparatus using the three-line comb filter can obtain a color signal having good vertical resolution and reduced horizontal DOT interference by using vertical correlation between three horizontal scan lines. Even in a system using a PAL two-line comb filter, it is desirable to provide a color signal separation device common to NTSC type color signal separation device while increasing separation efficiency by using a vertical correlator used in the color signal separation device. Do.

In the present invention, in addition to the two signals in the PAL two-line comb filter in order to operate the same as the three-line comb filter of the NTSC system is to supply a separate pseudo signal to the vertical correlator 15. The configuration and operation of the present invention will be described in detail with reference to FIGS. 2, 3A-3C, 5 and 6A-6C.

5 is a view showing an embodiment of the present invention. In FIG. 5, the same code | symbol is used for the component which has the same operation | movement as FIG. 1, and the description is abbreviate | omitted. The color signal separation device of the present invention shown in FIG. 5 includes a third delay unit 16, a second inverter 17, a fourth and fifth band pass filters 18 and 19, and a second zero level signal generator 20. .

The third delay unit 16 has a characteristic of delaying the PAL signal by 2H (H is the period of the horizontal scan line). The fourth fifth band pass filters 18 and 19 have a characteristic in which the frequency (4.43 MHz) of the PAL color carrier carrier is used as the pass frequency.

The operation of the color signal separation device of the present invention shown in FIG. 5 will be described in detail with reference to FIGS. 6A-6C, 7A-7D and 8A-8D.

First, the color signal separation operation in the vertical decorrelating portion will be described.

It is assumed that a carrier color signal having an original image as shown in FIG. 2 is applied to the color signal separation apparatus of FIG.

The signal corresponding to the portion B is output from the third delay unit 16, and the horizontal scan line signals s, t and u, which are sequentially arranged on the screen and whose intervals are 2H, are represented as shown in FIG. 6A. In this case, in the color signal separation apparatus of FIG. 5, the signals o of each part are d, e, f, g, h, i, j, k, l, m, n and the signal o from which the cross color is removed is shown in FIG.

When the signal corresponding to the portion D is output from the third delay unit 16, horizontal scan line signals s, t and u which are arranged sequentially on the screen and whose intervals are 2H are displayed as shown in FIG. 6B. In this case, in the color signal separation apparatus of FIG. 5, the signals of the respective parts d, e, f, g, h, i, j, k, l, m, n and o are shown in FIG. 7B. It can be seen that the color signal is not output in the signal o.

In the case where the signals s, t and u with sequential order and intervals of 2H have the same color, all signals e, f, g, h, i, j, k, l, m, n and the same color The signal o with is as shown in FIG. 7C. In addition, when all signals do not have color, a signal o without color is also obtained.

An operation of removing the luminance signal of the component corresponding to the frequency of the color subcarrier will be described. Since there is no phase difference of the luminance signal between adjacent horizontal scan lines, horizontal scan line signals s, t, and u having a sequential interval of 2H on the screen are displayed as shown in 6D. In this case, the signals d, e, f, g, h, i, j, k, l, m, n and o in the color signal separator of FIG. 5 are shown in FIG. 7D. It can be seen that the cross color is removed in the signal o.

As described above, it can be seen that the color signal separation apparatus of the present invention shown in FIG. 5 can share a vertical correlator used for a three-line comb filter while operating as a two-line comb filter in the PAL method.

8 is a view showing another embodiment of the present invention. The color signal separation device shown in FIG. 8 is a color signal separation device for both NTSC / PAL. In addition to the color signal separation device of the present invention shown in FIG. 5, the first and second delayers for delaying the NTSC video signal by 1H (1, 2), first inverter 3, first and second and third band pass filter (4, 5, 6), the first and the second and third frequency of the NTSC type color subcarrier as the pass frequency Three switches 21, 22, and 23;

The first switch 21 selects an NTSC color signal passed through the first bandpass filter 4 and a PAL color signal passed through the fourth bandpass filter, and supplies it to the vertical correlator 15.

The second switch 22 selects the bandpass NTSC color signal from the second bandpass filter and the PAL type color signal from the fifth bandpass filter and supplies them to the vertical correlator 15.

The third switch 23 selects the NTSC color signal and the zero level signal from the zero level generator 20, and supplies them to the vertical correlator 15.

The person familiar with the processing of the video signal will be familiar with determining whether the input video signal is NTSC or PAL. It will also be familiar with the method for generating a signal for controlling the first second third switch of the present invention and controlling the switch using the same.

In the apparatus shown in FIG. 8, it can be seen that the sum of the delay times of the first delay unit and the second delay unit is almost the same as the delay time of the third delay unit. That is, since the first delay and the second delay each have a delay period of 63.5 ms, the sum of them is 127 ms, and the third delay is almost similar since the third delay is 128 ms.

In the apparatus shown in FIG. 8, when the memory based delay is applied, two 1H delays may be configured to act as a third delay to reduce the number of memories. Specifically, only 1H delayers suitable for two NTSC methods are provided, and when applied to the PAL method, these two 1H delayers are connected in series to serve as 2H delayers according to the PAL method.

It will also be well known to separate the luminance signal using the color signal obtained through the color signal separation apparatus of the present invention.

Such a luminance signal separation device will usually include an adjustment delay and an adder for correcting the transmission delay error with the color signal obtained through the vertical correlator.

9 is another embodiment of the color signal separation device of the present invention.

The color signal separation device shown in FIG. 9 further comprises a fourth switch 24, a delayer 25 and a subtractor 26 for selecting NTSC or PAL video signals delayed by 1H for the color signal separation device according to FIG. Equipped.

The delayed signal through the fourth switch 24 is adjusted by the correction delayer 25 so as to properly maintain the phase with the color signal o.

The subtractor 26 is supplied with the signal through the fourth switch 24 and the correction retarder 25, and the subtractor is supplied with the color signal o.

The output terminal of the subtractor 26 can obtain the luminance signal from which the color signal has been removed.

Therefore, it is apparent that the objects and spirit of the present invention should be determined by the appended claims rather than being limited to the embodiments presented.

Claims (4)

An apparatus for separating a color signal from a PAL video signal including a color signal modulated by a color carrier, wherein the PAL video signal is introduced and delayed by two horizontal syringes according to the PAL method. group; An inverter for introducing an output of the retarder and outputting the phase inverted; A first zero level signal generator for generating a color signal modulated by a zero level chroma signal; A first low voltage detector configured to input the output of the video signal and the inverter and to select and output a signal having a low voltage level among them; A second low voltage detector configured to input an output of the inverter and an output of the first zero level signal generator, and select and output a signal having a low voltage level among them; A first high voltage detector configured to input the output of the video signal and the first inverter and to select and output a signal having a high voltage level among them; A second high voltage detector configured to input an output of the inverter and an output of the first zero level signal generator and to select and output a signal having a high voltage level among them; A second zero level signal generator for generating a color signal modulated by a zero level chroma signal; A third high voltage detector configured to input an output of the first low voltage detector, an output of the second low voltage detector, and an output of the second zero level signal generator, and select and output a signal having a high voltage level among them; A third low voltage detector configured to input an output of the first high voltage detector, an output of the second high voltage detector, and an output of the second zero level signal generator, and select and output a signal having a low voltage level among them; And an adder for introducing the output of the third high voltage detector and the output of the third low voltage detector and adding them to output a color signal separated from the image signal. 2. The apparatus of claim 1, further comprising: a first band pass filter for bandpass filtering the image signal at a frequency of a color carrier according to a PAL scheme and providing the first low voltage detector and the first high voltage detector; And a second band pass filter for band-pass filtering the output of the inverter by the frequency of the color carrier according to the PAL method and providing the first low voltage detector, the second low voltage detector, the first high voltage detector, and the second high voltage detector. Color signal separation apparatus characterized in that it comprises. An apparatus for separating color signals from an NTSC video signal or a PAL video signal including a color signal modulated by a color carrier, in which an NTSC video signal is introduced and equal to one horizontal syringe between NTSC methods. A first delay unit for delaying output; A first inverter which inputs the output of the first delay and inverts the output of the first delay; A second delay unit for introducing the output of the first delay unit and delaying the output of the first delay unit by one horizontal syringe according to the NTSC method; A third delayer for introducing the PAL video signal and delaying the PAL video signal by two horizontal syringes according to the PAL method; A second inverter that inputs the output of the third delay and inverts the output of the third delay; A first zero level signal generator for generating a color signal modulated by a zero level chroma signal; A first switch for selecting and outputting one of the PAL video signal and the NTSC video signal in response to an NTSC / PAL selection signal applied thereto; A second switch for selecting and outputting one of an output of the second inverter and an output of the first inverter in response to an NTSC / PAL selection signal applied thereto; A third switch for selecting and outputting one of an output of the first zero level signal generator and an output of the second delay unit in response to an NTSC / PAL selection signal applied thereto; A first low voltage detector for introducing an output of the first switch and an output of the second switch and selecting and outputting a signal having a low voltage level among them; A second low voltage detector for introducing an output of the second switch and an output of the third switch, and selecting and outputting a signal having a low voltage level among them; A first high voltage detector for introducing an output of the first switch and an output of the second switch, and selecting and outputting a signal having a high voltage level among them; A second high voltage detector for introducing an output of the second switch and an output of the third switch, and selecting and outputting a signal having a high voltage level among them; A second zero level signal generator for generating a color signal modulated by a zero level chroma signal; A third high voltage detector configured to input an output of the first low voltage detector, an output of the second low voltage detector, and an output of the second zero level signal generator, and select and output a signal having a high voltage level among them; A third low voltage detector configured to input an output of the first high voltage detector, an output of the second high voltage detector, and an output of the second zero level signal generator, and select and output a signal having a low voltage level among them; And an adder for introducing the output of the third high voltage detector and the output of the third low voltage detector and adding them to output a color signal separated from the image signal. A first band pass filter for bandpass filtering the image signal of the NTSC system to a frequency of a color carrier according to the NTSC system and providing the first signal to the first switch; A second band filter for band-pass filtering the output of the first inverter at a frequency of a color carrier according to an NTSC scheme and providing the second switch to the second switch; A third band pass filter for bandpass filtering the output of the second delay unit by the frequency of the color carrier according to the NTSC scheme; A fourth band pass filter for bandpass filtering the PAL video signal using a frequency of the color carrier according to the PAL method and providing the PAL video signal to the first switch; And a fifth band pass filter for bandpass filtering the output of the second inverter by the frequency of the color carrier according to the PAL method and providing the second switch to the second switch.