KR940000981B1 - Figure correcting system for video signal - Google Patents

Abstract

The video signal contour correcting system includes a first delay for delaying received video signal for a predetermined time, a first inverter for phase-converting the video signal, a first adder for adding the outputs from the first delay and first inverter, a second delay for delaying the output of the first delay for a predetermined time, a second inverter for phase-inverting the output of the second delay, a second adder for adding the outputs from the second inverter and first delay, a third adder for adding the outputs of the first and second adders, an amplifier for amplifying the output of the third adder, a fourth adder for adding the outputs from the amplifier and first delay, an adjust terminal for adjusting delay time of the first and second delays, and a level controller for controlling gain of the amplifier, thereby widening the adjustment range, and integrating the circuit with simple and accurate controlling of the adjustment.

Description

Image signal contour correction system

1 is a block diagram of the image signal contour correction system of the present invention.

2 is a signal waveform diagram of each part of the circuit shown in FIG.

FIG. 3 is a diagram illustrating an embodiment of implementing a time delay system using an operational transfer conductance (OTA). FIG.

4 is a signal waveform diagram showing a change in contour correction according to a time delay change.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal contour correction system, and more particularly, to a video signal contour correction system for correcting contours of a video signal by simultaneously controlling a time delay and a magnitude of a signal amplitude in a video signal player such as a VCR or a VOP.

In general, a video adjustment device such as a VCR or VOP has a screen adjustment function. One of the screen adjustment functions is a contour correction function, which corrects the contour of a video signal. The system is composed of a time delay unit, a comparison unit, a limiter unit, and a fixed time delay unit and a contour correction terminal that performs amplitude control. The system processes an input video signal using a delay value of a predetermined time signal, and a comparison unit and a limiter unit. After adjusting the amplitude, the contour is adjusted by amplitude control.

However, the conventional video signal contour correction system does not use the correlation between the time delay unit and the amplitude control unit, and the contour correction is performed only by the amplitude control, so that the extended amplitude is fixed, so that the control range is extremely limited.

The present invention has been invented to eliminate the drawbacks of the conventional image signal contour correction system. The control range is wide and controlled by simultaneously controlling the magnitude of the time delay and the signal amplitude using the correlation between the time delay unit and the amplitude control unit. The purpose of the present invention is to provide a video signal contour correction system that is relatively simple and accurate, but can be integrated.

Hereinafter, the configuration, operation, and effects of the present invention will be described in detail with reference to the accompanying drawings.

In order to achieve the above object, the image signal contour correction system of the present invention includes a first delay unit 1 for delaying an input image signal VS for a predetermined time and an inverter IV for phase reversing the image signal VS. ₁ ), a first adder 2 _a that adds the output of the first delay unit 1 and the output of the inverter IV ₁ , and a second delay that delays the output of the first delay unit 1 for a predetermined time. A first 1 ', an inverter IV ₂ which inverts the output of the second delay unit 1', an output of the inverter IV ₂ and an output of the first delay unit 1 '. second adder (2 _b), the first and second adder means for amplifying amplifies the output of the third adder (2 _c), a third adder (2 _c) for adding the output of the _{(2 a, 2 b) (} 3), Adjustment to adjust the delay time of the 4th adder ( _2d ) which adds the output of the amplification means (3) and the output of the said 1st delay part (1), and the said 1st, 2nd delay parts (1, 1 '). Consisting of a level adjusting section 4 for adjusting the gain of the terminal X and the amplifying means 3 .

FIG. 1 is a block diagram of the video signal contour correction system of the present invention, and FIG. 2 is a signal waveform diagram of each part of the circuit shown in FIG. 1, and when the video signal VS which is an A signal shown in FIG. The image signal (VS; A signal in FIG. 2) inputted to the first adder 2 _a and inverted by the inverter IV ₁ and input to the first adder 2 _a is delayed after T _d time. It is applied with the type force of the first adder 2 _a . Therefore, the first adder (2 _a) In addition to the output signal (B) of the inverted signal of the first delay section (1) of the video signal (VS), and outputs an addition signal (D). Meanwhile, since the signal B delayed by the first delay unit 1 is inverted in the inverter IV ₂ after being delayed again by the time T _d in the second delay unit 1 ', the output signal of the inverter IV _{2 is} shown in FIG. is in a C signal shown in is applied to the input of the second adder (2 _b) to the other input of the second adder (2 _b) is because the addition is applied to the output signal (B) of the first delay unit (1) The addition signal E is output from the second adder 2 _b .

Accordingly, the third adder 2 _c adds the output signal D of the first adder 2 _a and the output signal E of the second adder 2 _b to output the addition result to the amplifying means 3. Therefore, the output signal of the amplifying means 3 becomes the F signal shown in FIG. Therefore, the fourth adder 2 _d adds the output signal F of the amplifying means 3 and the output signal B of the first delay unit 1 to output the G signal shown in FIG. Done.

On the other hand, the level adjusting section 4 is necessary to determine the delay time adjusting range of the first and second delay parts 1 and 1 'and the amplitude adjusting range of the amplifying means 3. That is, the gain of the amplifying means 3 can also be adjusted by changing the voltage of the adjusting terminal X, and can also be configured using, for example, an operational transfer conductance.

In this way, the A signal of FIG. 2, which is an input image signal VS, is output as the G signal of FIG. 2 through the contour correction system of the present invention, so that its amplitude is emphasized in a steep waveform as shown in the G signal. do. That is, the contour correction level of the video signal is adjusted by simultaneously adjusting the magnitude of the time delay and the signal amplitude.

FIG. 3 is a diagram showing an embodiment of implementing a time delay system using OTA, and FIG. 4 is a signal waveform diagram showing a contour correction change according to a time delay change. The relationship between the input and the output of ie the transfer function H _(s)

Given by

do. Therefore, the time delay is given as the derivative of the transfer function H (5) with respect to frequency, and the value can be expressed by the following equation. That is, the time delay λ (W) is

It becomes As can be seen from Equation (4), the time delay λ (W) has a maximum value when W = W _p , changes the transfer conductance value of the operational conductance, and the time delay value is changed for a constant frequency. In other words, if the voltage of the adjustment terminal X is changed, the value of the transfer conductance of the operational transfer conductance changes so that the time delay value can be changed.

4 is a diagram showing the change in contour correction according to the change of the time delay value, wherein the signal whose contour correction is the image signal A 'as the input signal with the time delay value T _d1 is the B' signal and the time delay value T is shown in FIG. The signals contoured with _d2 are shown as C ′ signals, respectively (T _d1 > T _d2 ).

In general, when the time delay is too large in the delay part, the boundary surface is spread on the screen. To remove this, it may be effective to shorten the time delay, and as shown in FIG. When reduced, contour correction can be made effectively.

The video signal contour correction system of the present invention, which operates as described above, has the advantage that the control range is widened by controlling the time delay and the magnitude of the signal amplitude simultaneously by using the correlation between the time delay unit and the amplitude control unit. This relatively simple and accurate yet has the advantage of integrated circuit.

Claims (1)

A first delay unit 1 for delaying the input image signal VS for a predetermined time, an inverter IV _{1 for} inverting the phase of the video signal VS, an output of the first delay unit 1, and an inverter a first adder (2 _a), the first delay unit (1) a second delay unit (1 '), a second delay unit (1') to output a predetermined time delay for adding the output of the (IV ₁₎ Inverter IV _{2 for} reversing the output, second adder 2 _b for adding the output of inverter IV ₂ and the output of the first delay unit 1 ′, and first and second adders 2 _a a third adder (2 _c, which adds the output of the 2 _b)), the third adder amplifying means for amplifying the output of the (2 _c) (3), amplifying means (3) output and the first delay unit (1 in To adjust the gain of the fourth adder ( _2d ) that adds the output of &_lt; _{RTI ID} = 0.0 > (2) < / _RTI > Image signal contour correction system composed of a level adjusting section (4).