KR100234742B1 - Device for compensating colour signal perimeter - Google Patents

Abstract

The present invention relates to a device integrating a VTR and a monitor, and aims to correct a contour of a color signal.

Demodulation means (1) for demodulating the color signal in VTR7 into the color difference signal, contour correction means (2) for correcting the contour by correcting the frequency band of the color difference signal sent from the demodulation means (1), and the corrected color difference signal; Conversion means 3 for converting the luminance signal into an RGB signal, a modulation means 4 for converting the color difference signal corrected by the contour correction means 2 into a color signal, and conversion for mixing and outputting the conversion of the luminance signal and the color signal. It consists of the mixing means 5.

Description

Color signal contour correction device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device integrating a VTR for recording and reproducing a composite video signal and a monitor for displaying a screen of a reproduced image, and more particularly, to a device incorporating a color signal contour correction circuit in a VTR.

6 is a diagram showing the basic configuration of a conventional color signal contour correction apparatus.

The C signal of the output of the VTR is modulated by the color difference signal RY signal and the BY signal by the demodulator 9, and the color signal contour correction circuits 10 and 11 correct the contour of the color difference signal, and then modulate it by the modulator 12. The mixed circuit 16 is mixed to reproduce the composite video signal, and is output from the VTR connector 17 to the outside.

The reproduced composite video signal is sent to the monitor side via a video cable connecting the VTR connector 17 and the monitor connector 18. The Y / C signal separation circuit 19 on the monitor side separates the composite video signal into a Y signal and a C signal, and the C signal is demodulated by the color difference signal R-Y signal and B-Y signal by the demodulator 9. The demodulated R-Y signal, B-Y signal, and Y signal are converted into RGB signals by the RGB matrix circuit 13. The G-Y signal is generated by vector synthesis of the R-Y signals in the matrix circuit 13. The converted RGB signal is displayed on the CRT 14.

Currently, the VTR that is generally used is narrow because the band of the color signal is ± 500 KHz, so that the color blur in the horizontal direction connected to the monitor becomes large, and thus, it is not always good picture quality. In order to correct this, the above-described conventional color signal contour correction device is added to the VTR. However, since the color signal is demodulated separately from the VTR side and the monitor side as a difference signal, there is a problem that the image quality deteriorates each time.

As shown in Fig. 6, since the conventional color signal contour correcting device, the VTR and the monitor are separated, and are connected and used with a video cable, the color signal contour correction circuits 9 and 10 are connected to the VTR output on the VTR side. (11, 12) were added, and the C signal was demodulated again on the monitor side, resulting in degradation of transient response characteristics and frequency characteristics.

An object of the present invention is to improve the deterioration of image quality such as frequency characteristics and transient response characteristics during modulation and demodulation.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing an important part configuration of a color signal contour correction apparatus based on the present invention.

2 is a diagram showing an embodiment of a color signal contour correction apparatus based on the present invention;

3 is a diagram showing a comparison between a conventional color signal contour device and a color signal contour correction device of the present invention.

4 is a detailed block diagram of a color difference signal contour correction circuit;

5 is a diagram illustrating contour correction of color signals.

6 is a diagram showing the configuration of a conventional color signal contour correction apparatus.

<Explanation of symbols for main parts of drawing>

1: demodulation means 2: contour correction means

3: conversion means 4: modulation means

5: switching mixing means 6: CRT

7: VTR 9: demodulator

10, 20: R-Y signal contour correction circuit

11, 26: B-Y signal contour correction circuit

12 modulator 13: RGB matrix circuit

14: CRT 15: switch

16, 24: Mix circuit 17: VTR connector

18: Monitor connector 19: Y / C signal separation circuit

21: input amplifier 22: delay 1

23: Delay 225: Output Amplifier

26: amplifier mix circuit

As shown in Fig. 3, the VTR and the monitor are integrally formed, and as shown in FIG. 3, the display of the demodulator 9 → RY, BY signal contour correction circuits 10, 11 → modulator 12 → demodulator 9 → Brown tube 14 is displayed. In the present invention, the two steps of modulation and demodulation are omitted, as shown in the demodulator 9 → RY, BY signal contour correction circuits 10, 11 → Brown tube 14. The number of parts was also significantly reduced. Accordingly, it is possible to prevent deterioration of frequency characteristics and colors due to modulation and demodulation.

2 is a diagram showing an embodiment according to the present invention. The gist in this embodiment is as follows. According to the embodiment of the present invention, it consists of a VTR7, a demodulator 9, an R-Y signal contour correction circuit 10, a B-Y signal contour correction circuit 11, an RGB matrix circuit 13, and a modulator 12. In addition, by eliminating the method of connecting the VTR and the monitor with a video cable as in the related art, the circuit configuration is simplified and the signal processing is simplified by integrating the VTR and the monitor, thereby reducing the color and frequency characteristics of the modulator. You can prevent it.

9 is a demodulator for generating the color difference signal R-Y signal and the B-Y signal from the C signal output from the Y / C signal separation with VTR. The reason for using the color difference signal which derives the luminance signal from the color signal is to consider the commonality between the color image and the black and white image. The demodulation method uses a two-axis demodulation method in which the R-Y signal and the B-Y signal are demodulated separately, and the demodulated signal is mixed into an RGB matrix circuit 13 described later to obtain a G-Y signal.

The mixing ratio of the color difference signals at this time is obtained by the following equation.

R-Y = 0.70R-0.59 G-0.11R

B-Y = -0.30R-0.59G + 0.89R

The demodulator 9 of the color signal requires an ACC (Auto Color Control) circuit that changes the output voltage of the RGB signal accordingly when the color burst level changes. This circuit is necessary because the color signal is based on the level and phase of the color burst signal. A VCO (voltage controlled oscillator) circuit (not shown) for generating a demodulation signal (carrier) is compared with the oscillation output from the VOC, and an APC (Auto Phase Control) circuit (not shown) for controlling the VOC is required. In addition, a color killer circuit (not shown) that cuts unnecessary color signals is also required for black and white images.

10 and 11 are R-Y signal contour correction circuits and B-Y signal contour correction circuits. 4 shows an internal block diagram of the chrominance signal contour correction circuit, which is basically a mix circuit 24 which mixes two delay stages 22 and 23 and an undelayed signal after the input amplifier 21. And an amplifier amplifier circuit 26 that amplifies and mixes the non-delayed RY signal and the first delayed RY signal by amplifying and mixing the mixed signal and applying the mixed signal to the mix circuit 24. Since the circuit for correcting the contour of the R-Y signal and the B-Y signal is basically the same, a circuit for correcting the R-Y signal will be described.

The RY signal input from the demodulator 9 is amplified by the first stage input amplifier 21, and the signal passed through the delay 1 and the delay 1 in the delay 1 (DL1) 22 and the delay 2 (DL2) 23, and the signal passed through the delay 1, respectively. After amplifying and mixing signals that do not pass through, the mixed signal and the signal passing through the delay 2 are mixed by the mixing circuit 24, and amplified and output by the output amplifier 25 at the final stage. As a result, the primary color difference signal becomes a second derivative waveform. The left waveform in the block diagram shows signal waveforms output to the respective parts 1 to 6 of the color difference signal contour correction circuit. 5 shows a form in which the outline of the color difference signal is corrected. It can be seen that the edge of the original color difference signal is overshooted (white level) and preshooted (black level) and emphasized through the contour correction circuit. In this way, the white level that emphasizes the edge is high, and the black level is low, so that the resolution is improved.

12 is a modulator for generating color signals from contour corrected color difference signal R-Y signal and B-Y signal. A color signal is generated from a chrominance signal including color and color density information. As the modulation method of the chrominance signal, an orthogonal two-phase modulation method (balanced modulation) in which the R-Y signal and the B-Y signal are 90 ° displaced and synthesized is used.

A phase circuit (not shown) shifts the RY signal to + 90 ° and the BY signal to 0 ° phase to shift the RY signal and color server carrier to the RY signal modulation circuit (not shown), and the BY signal. Each color subcarrier is added to a BY signal modulation circuit (not shown) to modulate the color subcarrier. In this way, color signals are generated from the R-Y and B-Y signals. At the time of modulation, since a color signal is determined according to the level of a chrominance signal, a color burst signal is also input to a modulation circuit.

13 is an RGB matrix circuit which generates an RGB signal from the luminance signal and the corrected chrominance signal. The RGB signal is reproduced from the Y-signal, the R-Y-signal contour correction circuit 10, and the B-Y-signal contour correction circuit 11 whose contours are corrected in VTR7, and the R-Y 'and B-Y' signals. Here, the G signal vector synthesizes the R-Y 'signal and the B-Y' signal, and adds the Y signal to this to obtain an RGB signal. The mixing ratio of the G-Y signal and the RGB signal is obtained by the following equation.

G-Y =-[0.51 (R-Y) + 0.19 (B-Y)]

R = R-Y (+ Y)

G = G-Y (+ Y)

B = B-Y (+ Y)

As a result of the addition of the R-Y 'and B-Y' signals, the G-Y signal is naturally also a corrected signal.

15 is a switch for switching between the Y signal reproduced at VTR7 and the uncorrected C signal or the contour corrected C 'signal. The color signal of the switching method is mixed with the Y signal in the next mix circuit 16.

16 is a mix circuit 16 which synthesizes a composite video signal by mixing the Y signal and the C signal or C 'signal switched by the switch 15.

17 is a VTR connector 17 for outputting a composite video signal to the outside. You can connect the cable here to display the video on another monitor.

As described above, according to the present invention, the following remarkable effects are obtained.

(1) System configuration is compact by integrating VTR and monitor.

(2) Color and frequency characteristics are improved, so color bleeding in the horizontal direction is eliminated and image quality is improved.

(3) Since the signal processing process is simplified, the signal deterioration due to the modulation and demodulation can be eliminated.

(4) By simplifying the signal processing process, the number of circuit components can be greatly reduced.

Claims (5)

A color signal contour correcting apparatus for correcting the contour of a color signal output from a video tape recorder, comprising: demodulation means (1) for demodulating a color signal from a video tape recorder (7) into a color difference signal and sent from said demodulation means (1); Contour correction means (2) for correcting contours by correcting a frequency band of the color difference signal, conversion means (3) for converting the corrected color difference signal and the luminance signal into an RGB signal, and correction in the contour correction means (2) And a switching means (5) for switching and mixing the luminance signal and the color signal and outputting the modulated means (4) for modulating the corrected color difference signal into a color signal. 2. The contour correction means according to claim 1, wherein the contour correction means (2) comprises: an RY signal contour correction circuit (10) for correcting the contour of a first color difference (RY) signal for deriving a luminance signal from a red signal, and a luminance signal from a blue signal; And a BY signal outline correction circuit (11) for correcting the outline of a second color difference (BY) signal. 2. The switching mixing means (5) according to claim 1, wherein the switching mixing means (5) comprises a switch (15) for switching between a color signal before contour correction and a color signal after contour correction, a luminance signal output from the video tape recorder (7), and And a mix circuit (16) for mixing the color signals after switching with the switch (15) and before or after contour correction. RY signal contour correction circuit 10 for correcting the contour of demodulator 9 and first color difference signal RY, and BY signal contour correction circuit 11 for correcting the contour of second color difference signal BY and the RY signal A modulator 12 for modulating the corrected color signal C from the first corrected color difference signal RY and the second corrected color difference signal BY whose contour is corrected by the contour correction circuit 10 and the BY signal contour correction circuit 11. And a color signal C separated by the luminance and color signal (Y / C) separation circuit 19. The first color difference signal RY and the second color difference signal BY and the luminance and color signal ( Y / C) The color of the video signal processing apparatus which constitutes a monitor section comprising an RGB matrix circuit 13 for converting the luminance signal Y separated by the separation circuit 19 into an RGB signal and reproduces the video signal of the VTR. In the contour correction apparatus, a demodulator 9 which modulates the first color difference signal RY and the second color difference signal BY from the color signal C is shared. Color outline correction device, characterized in that. 5. The color outline correction device according to claim 4, further comprising a switch (15) for switching the color signal (C) of the VTR and the corrected color signal (C) with contour correction.