KR970007852B1 - Moving factor based luminance/chrominance signal separator - Google Patents

Abstract

The apparatus separates luminance and color signals effectively from composite signals by selecting luminance signals of moving region due to line delay and luminance signals of still region due to frame delay adaptively according to the detected motion informations of image signals. The apparatus includes delay unit(14) which extracts luminance signal from composite synthesis signal by using 1H line delay, A/D converter unit(15) which converts the extracted luminance sigal, frame delay unit(16), motion detecting unit(17), A/D converter unit(18) which converts analog composite synthesis signal into digital signal , a first luminance signal detecting unit(19), a second luminance signal detecting unit(20), switching unit(21), and adder circuit(22).

Description

Luminance Signal / Color Signal Separator According to Moving Component

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a luminance signal / color signal separator according to a moving component, and more particularly, to a luminance signal (hereinafter referred to as Y signal) of a composite color television signal (hereinafter referred to as a V signal) obtained by frequency multiplexing a color signal in a high frequency region of the luminance signal. Signal) and a luminance signal color signal separator according to a moving component suitable for separating color signals (hereinafter referred to as C signals).

In the conventional motion detection using a motion component, a signal of only one frame difference is used as the motion information as it is, and a low pass filter (LDF) and a band pass filter (BPF) are used to obtain motion information of a luminance signal and a color signal. The luminance signal and the color signal were separated. After that, since the difference between the luminance signal and the color signal of one frame difference is obtained and used as motion information, the luminance signal and the color signal are executed differently according to the still region and the motion region.

In the current NTSC signal system, the C signal is a complex circuit obtained by frequency multiplexing the high frequency region of the Y signal. For this reason, a Y / C separation function is necessary for a television receiver. However, in this case, deterioration in image quality due to cross color, cross talk, etc. occurs due to insecure Y / C separation.

Recently, with the development of large-capacity digital memories, signal processing circuits for adaptive Y / C separation according to movement using delay circuits having a delay time equal to or higher than the vertical scanning frequency of a television signal have been proposed.

According to the prior art described in Japanese Patent Application Laid-Open No. 2,89532, as shown in FIG. 4, an NTSC V signal 401 is input to the input terminal 41, and the NT signal V signal ( 401 is supplied to the input terminals of the in-field Y / C separation circuit 44, the inter-frame Y / C separation circuit 45, the Y signal motion detection circuit 46, and the C signal motion detection circuit 47, respectively.

At this time, the in-field Y signal 402 and the in-field C signal 403 separated Y / C by the in-field filter in the in-field Y / C separation circuit 44 are the first signals of the Y signal mixing circuit 49. The input terminal and the first input terminal of the C signal mixing circuit 50 are respectively input. In the inter-frame Y / C separation circuit 45, the Y signal 404 separated by Y / C by the inter-frame filter and the C signal 405 separated by the frame Y / C are separated from the Y signal mixing circuit 49. It is input to the 2nd input terminal and the 2nd input terminal of the C signal mixing circuit 50, respectively.

On the other hand, the Y signal motion amount 406 detected by the Y signal motion detection circuit 46 is provided to one input terminal of the synthesis circuit 48, and the C signal motion amount detected by the C signal motion detection circuit 47. A signal 407 indicating is provided to the other input terminal of the synthesis circuit 48.

Next, the motion detection signal 408 synthesized in the synthesis circuit 48 is provided to the third input terminal of the Y signal mixing circuit 49 and the third input terminal of the C signal mixing circuit 50, respectively. The Y signal motion detection circuit 46, the C signal motion detection circuit 47, and the synthesis circuit 48 substantially constitute the motion detection circuit 480.

At this time, according to the movement output from the Y signal mixing circuit 49, the Y signal 409 which is adaptively separated by Y / C is sent to the output terminal 42, and also to the movement output from the C signal mixing circuit 50. Accordingly, the C signal 410 adaptively separated from Y / C is sent to the output terminal 43.

That is, the conventional apparatus having the above-described configuration separates the V signal 401 from the motion detection circuit 480 by Y / C, but outputs the Y signal motion detection circuit 46 and the C signal motion detection circuit 47. Are synthesized by the combining circuit 48, and it is determined whether the V signal 401 is a signal representing a stationary image or a signal representing motion.

In general, if the picture is a still picture, interframe Y / C separation using inter-frame correlation is performed to separate the Y and C signals, and if the picture is a moving picture, in-field Y / C using the inter-field correlation is used. C separation is performed to separate the Y and C signals.

As described above, the adaptive Y / C separation filter according to the conventional motion is Y in the field according to the combined amount of motion detected by the Y signal motion detection circuit 46 and the C signal motion detection circuit 47, respectively. The signals 402 and 403 by the / C separation circuit 44 and the signals 404 and 405 by the inter-frame Y / C separation circuit 45 are respectively mixed.

Therefore, since the filter characteristics in the still image and the filter characteristics in the moving image are completely different, there is an extreme change in resolution when the image moves from the still image to the moving image or when moving from the moving image to the still image. There was a problem that the degradation of the image quality during image processing was noticeable.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art as described above, wherein motion information of an image is detected by using a luminance signal component, and a motion area luminance signal and a frame based on a line delay based on the detection result. By adaptively selecting a stop region luminance signal based on a delay, a luminance signal / color signal separator according to a moving component capable of effectively separating a luminance signal and a color signal from a composite signal is provided.

In order to achieve the above object, the present invention provides a luminance signal / color signal separator which separates a luminance signal and a color signal from an analog composite signal of an analog type, and uses a 1H line delay to obtain a luminance signal from the composite composite signal. Delay and A / D conversion means for extracting and A / D converting the extracted luminance signal; Frame delay means for frame delaying the A / D converted luminance signal provided from the delay and A / D conversion means; The frame difference between the 1H line delayed luminance signal provided from the delay and A / D conversion means and the delayed luminance signal provided from the frame delay means is calculated, and the motion of the image is compared by comparing the calculated difference signal with a predetermined threshold value. Motion detection means for judging an area and a still area, and generating a switching control signal for adaptive selection of the luminance signal corresponding to the determination result; A / D conversion means for sampling the input analog composite composite signal at a predetermined sampling frequency and converting the digital composite signal into a digital signal; A first luminance signal detection circuit for detecting a luminance signal corresponding to a motion region in the A / D converted composite signal using a 1H line delay; A second luminance signal detection circuit for detecting a luminance signal corresponding to a still region in the A / D converted composite signal using a frame delay; Switching means for selectively outputting any one of the detected motion region correspondence luminance signal and the detected still region luminance signal as a final luminance signal of the input composite synthesis signal in response to a switching control signal from the motion detection means; And a color signal generation means composed of color signal generation means for generating a color signal by phase-adding the detected luminance signal provided from the switching means and the A / D converted composite signal provided from the A / D conversion means. Provide a color signal separator.

1 is a block diagram of a luminance signal / color signal separator according to a preferred embodiment of the present invention.

FIG. 2 is a specific circuit diagram of the first luminance signal detection circuit YC1 of FIG.

3 is a specific circuit diagram of the second luminance signal detection circuit YC2 of FIG.

4 is a block circuit diagram showing an example of an adaptive luminance signal / color signal separation filter according to a conventional motion.

5 is a spectral diagram of a color carrier of a typical NTSC system.

* Explanation of symbols for main parts of the drawings

11: input terminal 12,13: output terminal

14: 1H line delay circuit 15, 18: A / D converter

16 frame delay circuit (FD) 17 motion detection unit

19: first luminance signal detection circuit (YC1) 20: second luminance signal detection circuit (YC2)

21: switching unit 22: addition circuit

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

As is well known, the motion region has high similarity with adjacent pixels in space, and the still region has high similarity with pixels in the time axis direction. Accordingly, the present invention aims to improve image quality in a reproduced motion image by differently applying luminance signal / color signal separation between the motion area and the still area based on the motion detection result in consideration of such area characteristics.

1 is a block diagram of a luminance signal / color signal separator according to a preferred embodiment of the present invention. As shown in the figure, the luminance signal / color signal separator of the present invention is a 1H line delay circuit 14, an A / D converter 15, a frame delay circuit (FD) 16, a motion detector 17, A A / D converter 18, a first luminance signal detection circuit 19, a second luminance signal detection circuit 20, a switching unit 21, and an addition circuit 22.

Referring to FIG. 1, the terminal 11 is an NTSC analog synthesized signal (V) input terminal as shown in FIG. 5, which shows, for example, the spectrums of color carriers for a motion picture and a still picture, respectively. The NTSC synthesized signal (V) input here is provided to the 1H line delay circuit 14 and the A / D converter 18, respectively.

On the other hand, the 1H line delay circuit 14 separates only the Y signal from the analog synthesized signal V using a filtering technique or the like which is well known in the art, and delays the separated Y signal during the 1H line so that the line ( The Y signal generated on the line 102, which is delayed on the 1H line, is converted into a digital signal through the A / D converter 15 using a predetermined sampling frequency and output to the line 103. Here, the 1H line delay circuit 14 may be configured as, for example, a conventional comb filter.

At this time, the 1H line delayed digital Y signal output on the line 103 is provided to the frame delay circuit 16 and the motion detector 17, respectively, and the frame delay circuit 16 converts the A / D converted Y signal into a frame. The delayed Y signal is provided to the motion detector 17 similarly to the Y signal on the 1H line delayed line 102 described above.

Therefore, the motion detection unit 17 calculates a frame difference between the 1H line delayed Y signal provided through the line 103 and the frame delayed Y signal provided through the line 104 and, for example, applies a mask to the resultant value. Judging the presence or absence of motion by applying the threshold value used, that is, if the calculated frame difference signal is compared with a predetermined threshold value, corresponding to the comparison result, the current input image is a motion region having a motion component or a motion component is determined. If it is determined whether or not it is a still area that does not have a control area, a control signal for switching the contacts (that is, a switching control signal for selecting a luminance signal) is generated based on the determination result. The switching operation of the switching unit 21 in response to the switching control signal from the motion detection unit 17 will be described later in detail.

On the other hand, the analog synthesized signal V on the line 101 input through the terminal 11 is provided to the A / D converter 18 for separation into a luminance signal color signal, which is an A / D conversion. In the unit 18, the input analog synthesized signal V is sampled at a predetermined predetermined sampling frequency, converted into a digital signal, and generated on the line 106. The digital synthesized signal on the line 106 is a first luminance. The signal detecting circuit 19, the second luminance signal detecting circuit 20 and the adding circuit 22 are provided respectively.

Next, the first luminance signal detection circuit 19 detects the luminance signal for the motion region using the 1H line delay from the digital synthesized signal provided from the A / D converter 18 through the line 106. The first luminance signal detection circuit 19, which is provided to the switching unit 21 via the line 107, is, for example, a 1H line delay circuit 23 and an adder 24, as shown in FIG. ) Can be configured.

Referring to FIG. 2, the 1H line delay circuit 23 delays the A / D converted synthesized signal on the line 106 by 1H and then outputs it to the adder 24 through the line 111, and the adder 24. In this case, the A / D converted composite signal on the line 106 and the delayed signal on the line 111 are added to generate the added Y 'signal on the output line 107 thereof. That is, the adder 23 receives the Y + C signal through the line 106 and the Y-C signal which is 180 degrees out of phase through the line 111, and extracts the Y 'signal by adding these two signals.

Therefore, when the output signal on the line 107 is Y ', the C output is Y' (Y ± C) ≒ ± C. Therefore, it is preferable to estimate Y 'so that the value of (Y-Y) becomes zero. To this end, in the first luminance signal detection circuit 19, as an example, as shown in FIG. 5B, the luminance signal average value between adjacent upper and lower lines is taken.

On the other hand, the second luminance signal detection circuit 20 detects the luminance signal for the motion region using the frame delay in the digital synthesized signal provided from the A / D converter 18 through the line 106 and then the line ( 108 to the switching unit 21, the second luminance signal detection signal 20 is an example of the line delay circuit 31, the adder 32 and 1/1 as shown in FIG. It can be comprised of two dividers 33.

Referring to FIG. 3, the line delay circuit 31 delays the A / D converted synthesized signal on the line 106 by 525H (one frame) and outputs it to the adder 32 through the line 112. In (32), the A / D converted composite signal on line 106 and the 525H delayed signal on line 112 are added and then provided to the next half frequency divider 33 through its output line 113. do. At this time, the extraction of the luminance signal is performed by adding the Y ± C signal on the line 106 and the Y-C signal in which the phase is inverted by 180 degrees on the line 111 through the adder 32.

Next, the 1/2 divider 33 divides the output luminance signal on the line 113 by 1/2 to generate a 1/2 'divided Y' signal on the line 108. In this case, it is preferable to estimate the Y 'signal on the half-divided line 108 so that the (Y'-Y) value becomes 0, as mentioned in the description of the first luminance signal detection circuit 19. . To this end, in the second luminance signal detection circuit 20, for example, as shown in FIG. 5A, the luminance signal average between pixels on a specific region (i.e., rectangular region) in space is taken.

That is, Figure 5 shows the NTSC system color carrier spectrum in the three-dimensional time frequency domain, in order to remove the interference such as cross color caused by the prior art described above, the present invention uses the properties of such spectrum Y Perform a / C split.

To this end, in the present invention, when the input image is a motion image, a carrier color signal is taken in an area (between adjacent upper and lower lines) indicated by diagonal lines in FIG. 5A using a comb filter having a one-line memory. In this case, the resolution of the inclination direction of the luminance signal may be slightly lowered, but the effect of precisely appearing without disturbing the motion of the image can be obtained.

Contrary to the above, when the input image is a still image, the carrier color signal fsc is taken in the region (specific region in space) indicated by diagonal lines in FIG. 5B by using a comb filter having a one-frame memory. In this case, unlike the above-described processing of the motion image, the spatial resolution of the luminance signal and the color signal does not decrease.

In conclusion, in the present invention, it is possible to perform effective Y / C separation for a motion picture and a still picture in consideration of such picture characteristics (spectrum characteristics).

On the other hand, the switching unit 21 is provided by the first luminance signal detection circuit 19 through the line 107 in response to the switching control signal based on the above-described motion detection result provided from the motion detection unit 17. Select one of the luminance signal Y 'for the motion region or the luminance signal Y' for the still region provided by the second luminance signal detection circuit 20 through the line 108 and select the luminance signal. Connect on output line 108.

That is, assuming that the area currently being processed is a motion area, the high level (or low level) provided from the motion detector 17 which detects such a motion by extracting a difference signal between the 1H line delayed signal and the frame delayed signal. In response to the switching control signal of, the switching unit 21 selects the luminance signal Y 'on the line 107 and outputs it on the line 109. In contrast, assuming that the area currently being processed is the movement area. In response to the low level (or high level) switching control signal provided from the motion detector 17, the switching unit 21 selects the luminance signal Y ′ on the line 108 to display the line 109 on the line 109. Output

At this time, the luminance signal Y 'for the motion area or the stop area generated on the output line 109 of the switching unit 21 is provided to the Y signal output terminal 12 and the addition circuit 22, respectively.

Meanwhile, the addition circuit 22 moves the A / D converted synthesized signal provided by the A / D conversion unit 18 through the line 106 and the movement provided by the switching unit 21 through the line 109. The luminance signal for the region or the stationary region is added, and the added output signal is connected to the output terminal 13 through the line 110. In other words, the addition circuit 22 generates an σC signal on its output line 110 through interphase addition (Y + C, Y-C addition), where ± represents a positive or negative value.

Accordingly, the output terminal 12 and the output terminal 13 output the separated luminance signal Y 'and the color signal ± C through adaptive luminance signal detection in consideration of the motion area according to the present invention.

As described above, the present invention, unlike the conventional comb filter having a 1H delay circuit, the motion region and stop using the 1 line delay (1H) and 1 frame delay (525H) circuit based on the detected motion information By selectively (adapting) the luminance signal and separation in the area, it is possible to prevent the image quality deterioration caused by the cross color or the cross talk, etc., thereby improving the image quality improvement effect on the reproduced image.

On the other hand, although the invention made by the present inventors has been described in accordance with the above embodiments, the present invention is not limited only to the above embodiments, and of course, various changes can be made without departing from the gist thereof.

Claims (5)

A luminance signal / color signal separator that separates a luminance signal and a color signal from an input analog composite signal, wherein the luminance signal is extracted from the input composite signal using a 1H line delay, and the extracted luminance signal is A. Delay and A / D conversion means for / D conversion; Frame delay means for frame delaying the A / D converted luminance signal provided from the delay and A / D conversion means; The frame difference between the 1H line delayed luminance signal provided from the delay and A / D conversion means and the frame delayed luminance signal provided from the frame delay means is calculated, and the calculated difference signal is compared with a predetermined threshold value to determine the image. Motion detection means for determining a motion area and a still area, and generating a switching control signal for adaptive selection of the luminance signal corresponding to the determination result; A / D conversion means for sampling the input analog composite composite signal at a predetermined sampling frequency and converting the digital composite signal into a digital signal; A first luminance signal detection circuit for detecting a luminance signal corresponding to a motion region in the A / D converted composite signal using a 1H line delay; A second luminance signal detection circuit for detecting a luminance signal corresponding to a still area in the A / D converted composite signal using a frame delay; Switching means for selectively outputting any one of the detected motion region correspondence luminance signal and the detected stop region correspondence luminance signal as a final luminance signal of the input composite synthesized signal in response to a switching control signal from the motion detection means; ; And a color signal generation means composed of color signal generation means for generating a color signal by phase-adding the detected luminance signal provided from the switching means and the A / D converted composite signal provided from the A / D conversion means. Color signal separator. 2. The circuit of claim 1, wherein the first luminance signal detection circuit comprises: a; A 1H line delay circuit for delaying the A / D converted synthesized signal provided from the A / D conversion means by 1H line; And an adder configured to add the A / D converted composite signal provided from the A / D converting means and the 1H line delay signal provided from the 1H line delay circuit to generate the motion area corresponding luminance signal. Luminance signal / color signal separator according to the component. 2. The circuit of claim 1, wherein the second luminance signal detection circuit comprises; A frame delay circuit for delaying the A / D converted synthesized signal provided from the A / D conversion means by one frame; An adder for extracting a luminance signal by adding an A / D converted composite signal provided from the A / D conversion means and a one frame delay signal provided from the frame delay circuit; And a divider for dividing the luminance signal output from the adder by a predetermined multiple to generate the stop region corresponding luminance signal. The luminance signal / color signal separator according to claim 1, wherein the movement detecting means determines the movement area of the image by masking the calculated difference signal with a predetermined threshold value. 2. A luminance signal / color signal separator according to a moving component according to claim 1, wherein the delay and A / D conversion means comprise a comb filter.