KR950012835B1 - The circuit of eleminating fishtailing phenomena in video signal - Google Patents

Abstract

a luminance/chrominance signal separating unit for separating a luminance signal and a chrominance signal from an image signal inputted; a fish tailing phenomenon removing unit for correcting the luminance signal outputted from the luminance/chrominance signal separating unit to output a corrected luminance signal in which a fish tailing phenomenon is removed; a chrominance signal demodulating unit for demodulating the chrominance signal outputted from the luminance/chrominance signal separating unit to output a color difference signal; and a color matrix unit for outputting a corrected color signal in which the fish tailing phenomenon is removed out of the corrected luminance signal and the color difference signal.

Description

Fish tailing phenomenon elimination circuit of video signal

1 is a conventional video signal processing circuit diagram.

2 is a view for explaining the cause of the fish tailing phenomenon.

3 is a diagram illustrating fish tailing on the screen.

4 is a video signal processing circuit diagram in which the elimination circuit of the present invention is constructed.

5 is a detailed circuit diagram of a fish tailing phenomenon removing unit of FIG.

6 (a) to 6 (g) are operating waveform diagrams of respective parts of FIG.

7 (a) to 7 (c) show that the fish tailing phenomenon is removed by the elimination circuit of the present invention.

* Explanation of symbols for main parts of the drawings

1: luminance / color separator 2: color demodulator

3: color matrix part 4: fish tailing phenomenon removal unit

10, 24: Inverter 11: 1H delay

12: compensation delay 13: white section detection unit

14 luminance difference detector 15 equal signal detector

16: transition region detection unit 17: retrace period detection unit

18: black line overlap detection unit 19: forward correction position detection unit

20: Reverse correction position detector 21: Correction determination unit

22 correction signal output unit 23

Y: luminance signal △ Y: correction signal

Y + △ Y: Corrected luminance signal C: Color signal

R-Y, B-Y: Color Difference Signal

According to the present invention, when a bundle of black lines or a horizontal pattern of clothes are formed on a screen in a slanted image processing apparatus such as a TV receiver, a VCR, a video camera and a camcorder, the bundle and the horizontal line of the black lines are displayed. The present invention relates to a fish tailing phenomenon elimination circuit of an image signal that eliminates fish tailing phenomenon that appears to be gathered and bent differently from actual stripes.

The conventional video signal processing circuit includes a luminance / color separator (1) for separating the luminance signal (Y) and the color signal (C) from an input image signal, as shown in FIG. 1, and the luminance / color separator. A color demodulator (2) for demodulating the color difference signal (RY) (BY) from the color signal (C) output from (1), the luminance signal (Y) and the color demodulator (2) of the luminance / color separator (1). The color matrix part 3 which detects the color signals R, G, and B from the color difference signal RY (BY) is formed.

In the conventional video signal processing circuit configured as described above, the luminance / color separator 1 separates the luminance signal Y and the color signal C from the input image signal.

The color signal C is a mixture of the color difference signals RY and BY. The color difference signal RY and BY are demodulated in the color demodulator 2, and the demodulated color difference signals RY and BY and the luminance signal. In (Y), the color matrix unit 3 detects and outputs the color signals R, G, and B.

When the color signal output from the conventional video signal processing circuit is applied to the electron gun of the CRT and displayed on the screen, a fish tailing phenomenon occurs in which bundles of black lines and horizontal streaks are formed differently from each other. It became.

That is, when photographing a subject, the imaging elements such as the merchandise correlator and the CCD are densely packed with scan lines n, n + 1, and n + 2 as shown in FIG. Due to this phenomenon, as shown in FIG. 3, when two black lines having a gentle inclination are expressed on the screen, the thickness of the black line at the portion where the black line intersects the scan line is slightly dropped from side to side. Since it is thicker than the thickness of the site, the wedge-shaped screen has a fish tailing phenomenon that looks like the wedge-side is bent unlike the actual shape.

The present invention has been made to solve the above-mentioned problems, and compares the signal of the current horizontal line with the signal of the horizontal line immediately before the luminance signal and detects a portion where the black line is thickly intersected with the scan line. Based on the middle part of the detected black line signal, the black line signal of the region overlapping the left and right sides of the upper and lower scanning lines is removed so that the fish tailing phenomenon does not occur and the bundle and the horizontal line of the black line form a gentle slope. It is an object of the present invention to provide a removing circuit for displaying stripes on a screen in the same manner as in the actual case, which will be described in detail with reference to the accompanying drawings of FIGS. 4 to 7. Identical symbols.

4 is a video signal processing circuit diagram in which the elimination circuit of the present invention is constructed, and as shown therein, a luminance / color separator 1 for separating the gray signal Y and the color signal C from an input video signal, and Luminance / Color Separator (1) A fish tail phenomenon removal unit 4 for correcting the luminance signal Y output from the message and outputting a corrected luminance signal Y + ΔY from which fish tailing is removed, and the luminance / color separator A color demodulator 2 for demodulating the color signal C outputted from (1) to output a color difference signal RY (BY), and a correction luminance signal Y + ΔY of the fish tailing phenomenon removing unit 4; And a color matrix section 4 for outputting a corrected color signal R + ΔY (G + ΔY) (B + ΔY) from which the fish tailing phenomenon is removed from the color difference signal RY (BY) of the color demodulator 2. It was.

In the present invention configured as described above, the luminance / color separator 1 separates the luminance signal Y and the color signal C from the input image signal, and removes the fish tailing phenomenon 4 from the separated luminance signal Y. Outputs a corrected luminance signal Y + ΔY by removing a portion where the black line crosses the scan line and appears thick.

Then, the luminance / color separator (1) and the color signal (C) separated by the message color demodulator (2) demodulate the color difference signal (RY) (BY), and the corrected color difference signal (RY) (BY) and the corrected luminance signal. At Y + ΔY, the color matrix unit 3 outputs the corrected color signals R + ΔY (G + ΔY) (B + ΔY) so that fish tailing does not appear on the screen.

FIG. 5 is a detailed circuit diagram of the fish tailing phenomenon removing unit 4 of FIG. 4, which is an essential part of the present invention. As shown therein, an inverter for inverting the luminance signal Y separated from the circuit / color separator 1 10), a 1H delay unit 11 for delaying the output signal of the inverter 10 for 1H (where H is a period of the horizontal synchronization signal), and a delay of the output signal of the 1H delay unit 11; A compensation section 12 comprising an operation amplifier 131 for detecting a white section from an output signal of the compensation delay unit 12, a resistor R1, and a threshold power supply V _TH1 . ) And a luminance difference detector comprising an inverter 141, an adder 142, and a delayer 143 which subtract the output signal of the inverter 10 from the output signal of the 1H delay unit 11 to detect the luminance difference. (14), a multiplier 151, an operational amplifier 152, and a low multiplier for detecting a signal having the same level from the output signal of the circuit difference detector 14; (R2) and the threshold power (V _TH2) to the same signal detector 15, a low pass filter (161 to detect the transition (transition) zone to remove a black line in the output signal of the synchronizing signal detector 15 ), A transition region detector 16 comprising a differentiator 162 and an operational amplifier 163, a synchronous detector 171, a retarder 172, 173, and a noar gate for detecting a return period from an output signal of the inverter 10. An AND gate for detecting the region where the black lines overlap by logically multiplying the return period detection unit 17, the white section detection unit 13, the same signal detection unit 15, and the return period detection unit l7 by (174). A resistor (R3) and a capacitor (181) for detecting a correction position in the forward transition region by the output signals of the black line overlap detector 18 (181, 182) and the transition region detector 16 and the black line overlap detector 18. C1), the detection of the forward correction position with the exclusive oragate 191 and the tri-state buffer l92 (19), resistors R4, condensers C2, and gates 201 for detecting the corrected position in the reverse transition region by the output signals of the transition region detection section l6 and the black line overlap detection section 18; Reverse correction position detection section 20 comprising a three-state buffer 202, the white section detection section 13, the same signal detection section 15, black line overlap detection section 18, forward correction position detection section 19 and reverse correction NAND gate 211, resistors R5 and R6, capacitors C3 and C4, operational amplifiers 212 and AND gates 213 for detecting whether the luminance signal Y is corrected using the output signal of the position detector 20 A bridge diode 221 and a low-pass filter for converting the output signal of the correction detector 21 and the luminance difference detector 14 into a correction signal and outputting the correction signal according to the output signal of the correction detector 21. 222 and the inverted tri-state buffer 223, the correction signal output section 22, and the output of the compensation delay unit 12 and correction signal output section 22 And an adder 23 for adding the signals, inverting the output signal of the adder (23) was composed of an inverter 24 which outputs the correction hoedo signal (Y + △ Y).

In the removal circuit of the present invention configured as described above, the luminance signal Y separated from the luminance / color separator 1 is inverted as shown in FIG. 6 (a) through the inverter 10, and the 1H delay unit 11 is performed. After being grounded for 1H period, the input is input to the adder 142 and delayed for a predetermined time through the compensation delay unit 12 and input to the white section detector 13 and the adder 23.

Then, the gray signal Y of the scanning line separated from the luminance / color separator 1 is inverted as shown in FIG. 6 (b) through the inverter 10, and the inverter 141 of the luminance difference detecting unit 14 is inverted. After inverting through), the input signal is added to the adder 142 and the output signal of the 1H delay unit 11, i.e., the adder 142 converts the luminance signal Y of the next scan line from the luminance signal Y of the current scan line. After subtracting, a luminance difference signal is output as shown in FIG. 6 (c), and the output luminance difference signal is delayed for a predetermined time by the delay unit 143, and then the same signal detector 15 and the transition region detector 16 ) And a correction signal output unit 22. Then, the correction signal output unit 22 rectifies the luminance difference signal output from the luminance difference detector 14 to the bridge diode 221 as shown in FIG. 6 (d), and passes the low pass filter 222 to the low pass filter 222. As shown in FIG. 6 (e), it is flat and input to the inverted tri-state buffer 223.

Here, the output signal of the low pass filter 222 is a signal close to the difference between the boundary between the black line region and the white region, and this signal is used as the correction signal ΔY in the present invention. The same signal detection unit 15 multiplies the output signal of the luminance difference detection unit 14 by the multiplier 151, so that the two scan lines are independent of the black line and the white as shown in FIG. 6 (f) of FIG. The same signal is detected from the signal, and the detected signal is compared and inverted by the threshold power supply V _TH2 in the operational amplifier 152 to output a pulse signal as shown in FIG. 6 (g).

In addition, the transition region detector 16 filters the output signal of the luminance difference detector 14 by the low pass filter 161 to detect the low pass signal as shown in FIG. 6 (h), and the detected low pass signal is differentiated. Differentiated at 162 and input to the operational amplifier 163, the operational amplifier 163 detects and outputs a transition region to remove the portion detected by the black line as shown in FIG. 6 (i).

On the other hand, in the luminance signal Y output from the inverter 10, the synchronization detector 171 of the retrace period detection unit 17 detects the synchronization signal as shown in FIG. In addition, the delayed signal is delayed by the delayer 172 and input to the noar gate 174, and the output signal of the delayer 172 is delayed again by the delayer 173 and inputted to the noargate 174. 174 outputs the retrace period detection signal including the front porch and the back porch to the synchronization signal as shown in FIG. 6 (k), and the operational amplifier 131 of the white section detection unit 13 is the compensation delay unit 12. The amplified output signal is compared with the threshold power supply V _{THI to} amplify and output a white period signal as shown in FIG. 6 (l).

In this way, the pulse signal output by the white section detection unit 13 and the retrace period detection unit 17 is logically multiplied by the AND gate 181 of the black line overlap detection unit 18, and the same signal detection unit 15 by the AND gate 182. Then, the result is multiplied by the output signal of λ) to detect the overlapping region of the black lines as shown in FIG.

The black line overlap region signal detected by the black line overlap detector 18 is input to one side of the exclusive oragate 191 of the forward corrected position detector 19 and the AND gate 201 of the reverse corrected position detector 20. It is applied to one input terminal of and integrated through the resistors R3, R4 and C1, C2 as shown in FIG. 6 (n), and the other input terminal of the exclusive oragate 191. And the exclusive oA gate l91 and the AND gate 201 are applied to the other input terminal of the AND gate 201, so that the pulse signal is as shown in FIG. 6 (a ') and FIG. 6 (b'). The output signal of the transition region detection unit 16 is applied to the control terminal of the three-state buffers 192 and 202, and the three-state buffers 192 and 202 are output. ) Outputs a pulse signal as shown in Fig. 6 (c ') and Fig. 6 (d').

Here, when the black line displayed on the screen is actually thicker than two scan lines, if the black line is judged to be an overlap of the black lines and removed, the screen state is rather damaged. Thus, in the present invention, the white section detecting unit 13 and the same signal detecting unit ( The output signal of 15) is inverted and logically multiplied by the AND gate 211 of the determination unit 21, and then integrated by the resistor R6 and the capacitor C4, and the output signal of the black line overlap detector 18 is resistance. (R5) and the condenser (C3) are integrated, and the integrated signal is compared and amplified by the operational amplifier 212 to output a pulse signal, and the AND gate 213 operates in accordance with the output signal of the operational amplifier 212 The output signals of the status buffers 192 and 202 pass through the AND gate 213 as shown in FIG. 6 (e ').

In this way, the inverted tri-state buffer 223 operates according to the pulse signal output from the AND gate 213 to invert the output signal of the low pass filter 222 to correct the signal as shown in FIG. 6 (f '). (ΔY) and the output correction signal (ΔY) is added from the adder 23 to the output signal of the compensation delay unit 12 as shown in FIG. 6 (g '), and the inverter 24 Inverted through) and output as a compensation luminance signal (Y + △ Y).

In the control circuit of the present invention, as shown in FIG. 7 (a), a black line having a gentle inclination is displayed on the screen as shown in FIG. 7 (b), whereby the fish tailing phenomenon appears. c) The fish tailing phenomenon does not appear by correcting the display as shown in FIG.

As described in detail above, the present invention compares the signal of the current horizontal line with the signal of the immediately preceding horizontal line in the luminance signal and detects a portion where the black line is thickly intersected with the scan line, and detects the portion of the detected thick portion. By removing the black line signal on the left and right sides of the upper and lower scanning lines with respect to the middle part of the black line signal, the fish tailing phenomenon does not occur and the bundles and horizontal stripes of the black lines that form a slanted slope are displayed on the screen in the same way as in the real world. Can be marked on.

Claims (2)

Fish tailing phenomenon by correcting the luminance / color separator 1 separating the luminance signal Y and the color signal C from the input image signal and the luminance signal Y output from the luminance / color separator 1. The fish tailing phenomenon removing unit 4 for outputting the removed corrected luminance signal Y + ΔY and the color signal C outputted from the luminance / color separator 1 are demodulated and the color difference signal RY (BY) Fish tailing phenomenon is removed from the color demodulator 2 outputting the < RTI ID = 0.0 > and < / RTI > the correction gray level signal Y + ΔY of the fish tailing phenomenon removing unit 4 and the color difference signal RY (BY) of the color demodulator 2. A fish tail phenomenon elimination circuit of the video signal, characterized by comprising a color matrix section 3 for outputting corrected color signals R + ΔY, G + ΔY, and B + ΔY. The fish tailing phenomenon removing unit (4) according to claim 1, wherein the fish tailing phenomenon removing unit (4) includes an inverter (10) for inverting the luminance signal (Y) separated from the luminance / color separator (1), and an output signal of the inverter (10). Here, H is a period of the horizontal synchronization signal) 1H delay unit 11 for delaying, a compensation delay unit 12 for delaying the output signal of the 1H delay unit 1l, and the compensation delay unit 12 A white section detection section 13 for detecting a white section from an output signal of the < RTI ID = 0.0 > 1, < / RTI > and a brightness difference detection section 14 for detecting a luminance difference by subtracting an output signal of the inverter 10 from an output signal of the 1H delay unit 11. ), The same signal detector 15 for detecting a signal of the same level from the output signal of the luminance difference detector 14, and a transition region for removing black lines from the output signal of the sync signal detector 15 Transition region detection section 16 for detecting a signal and an ear for detecting a return period in an output signal of the inverter 10 And a black line overlap detector 18 for detecting a portion where the black lines overlap by multiplying the output signal of the period detector 17, the white section detector 13, the same signal detector l5, and the retrace period detector 17; And a forward corrected position detector 19 for detecting a corrected position in the forward transition region using the output signals of the transition region detector 16 and the black line overlap detector 18, and the transition region detector 16 and the black line overlap. A reverse correction position detector 20 which detects a correction position in the reverse transition region by the output signal of the detector 18, the white section detector 13, the same signal detector 15, a black line overlap detector 18, The correction signal detecting unit 21 detects whether the luminance signal Y is corrected by the output signals of the forward correcting position detecting unit 19 and the reverse correcting position detecting unit 20, and the output signal of the luminance difference detecting unit 14 is corrected. Converting to a signal and correcting or not detecting unit 21 A correction signal output unit 22 for outputting according to the output signal, an adder 23 for adding output signals of the compensation delay unit 12 and the correction signal output unit 22, and an output signal of the adder 23; And an inverter 24 for inverting and outputting the corrected luminance signal Y + ΔY.