KR900003775B1 - Video contour compensating circuit - Google Patents

Abstract

The circuit for compensating the contour of a pictrue by controlling a luminance signal includes a delay circuit (11) for delaying an input video signal as much as one horizontal period, an adder (5) for adding input and output signals of a delay circuit, a delay circuit (12) for delaying the output signal of the adder as much as one horizontal period, a subtractor (9) for subtracting the output signal of the delay circuit (11), and an amplifier (4) for controlling the amplification ratio of the output signal of the subtractor.

Description

2D image contour correction circuit

1 is a horizontal contour correction circuit diagram and a timing chart.

2 is a block diagram of the present invention.

3 is a circuit diagram of the present invention.

4 is a timing chart of FIG.

* Explanation of symbols for main parts of the drawings

1-4: Amplifier 5-8: Adder

9: subtractor 10: low pass filter

11, 12: delay circuit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-dimensional image outline correction circuit for correcting a contour of an image to be clearly seen in a video signal processing circuit of a television.

In the conventional television video signal processing circuit, in order to prevent the loss of high frequency components, the image outline is corrected using a high frequency compensation circuit, but the image outline correction is completely complete, and thus a more advanced image outline correction circuit is required.

Due to this, recently, circuits for correcting image contours in the horizontal direction have been developed, but horizontal and vertical two-dimensional image contour correction circuits have not been developed yet.

SUMMARY OF THE INVENTION An object of the present invention is to provide a two-dimensional image outline correction circuit, which has not existed in the prior art, to obtain clear image quality by correcting the outline of an image horizontally and vertically.

In order to achieve the above object, in the present invention, a low pass filter and an adder are used to perform horizontal contour correction, and a horizontal period delay circuit and an adder are used to perform vertical contour correction. By adjusting the amplification factor, the degree of horizontal and vertical contour correction can be adjusted.

First, the horizontal outline correction circuit and the timing chart of FIG. 1 applied to the present invention will be described in order to help understanding of the present invention.

As shown in FIG. 1, the horizontal contour correction circuit passes the video signal through the low pass filter, subtracts the video signal from the original signal, and adds it to the original signal to obtain an output signal.

Referring to the timing chart of FIG. 1, when an input signal such as (a) passes through a low pass filter to obtain a waveform such as (b), and subtracts (b) waveform from (a) waveform again ( You can get the waveform as in c). The output (d) waveform can be obtained by adding the (c) waveform to the original signal (a) waveform, where (c) the dark areas are brighter and darker where the luminance changes by the waveform, i.e. where the contour changes horizontally. The part is made brighter to correct the outline of the image.

At this time, the waveform (c) is added to the original signal (a) through a control unit indicated as a constant r to adjust the degree.

Hereinafter, with reference to the block diagram of the present invention of Figure 2 and the circuit diagram of the invention of Figure 3 and the timing chart of Figure 4

The present invention will be described in detail.

2 is a block diagram schematically showing the present invention.

로서 입력신호를 반으로 감쇄시켜 출력하며, 또한 감산기(9)의 출력단에 연결된 증폭기(4)는 증폭율을 가변할 수 있는 증폭기이다.3 is a circuit diagram of the present invention, the input video signal is output by a delay of one horizontal period from the delay circuit 11, the adder 5 adds the input video signal and the output signal of the delay circuit 11, the adder The output signal of (5) is again outputted by one horizontal period delay from the delay circuit 12, and the adder 6 adds and outputs the input signal and the output signal of the delay circuit 12. The adder 7 adds the output signal of the delay circuit 11 and the output signal of the adder 6 to the low pass filter 10, and the subtractor 9 receives the low pass filter from the output signal of the delay circuit 11. The output signal of (10) is subtracted and added, and the adder 8 adds the output signal of the delay circuit 11 and the output signal of the subtractor 9 to finally output the corrected signal. In the circuit of the present invention, the output signals of the adders 5, 6, and 7 are output through the amplifiers 1, 2, and 3, respectively.

As a result, the input signal is attenuated in half and output, and the amplifier 4 connected to the output terminal of the subtractor 9 is an amplifier capable of varying the amplification factor.

The operation of the circuit of the present invention having the above configuration will be described with reference to the waveform diagram of FIG.

The input video signal as shown in (e) of FIG. 4 is delayed by one horizontal period and output through the delay circuit 11 of FIG. The above (e) and (f) signals are added by the adder 5, and are again applied to the delay circuit 12 through the amplifier 1. The adder 6 adds the input signal and the output signal of the delay circuit 12 to output a signal such as (g) through the amplifier 2.

The adder 7 adds the signal f which is the output signal of the delay circuit 11 and the signal g which is the output signal of the amplifier 2, and applies the low pass filter 10 through the amplifier 3 to the low pass. The pass filter 10 outputs a waveform as shown in (h). As shown in FIG. 4, the low pass filter 10 shows a waveform change at the portion where the brightness of the image signal is changed. Will be imported. Accordingly, the subtractor 9 subtracts the signal (h), which is the output signal of the low pass filter 10, from the signal (f), which is the output signal of the delay circuit 11, and outputs a waveform as shown in FIG. By applying to the adder 8 through the amplifier 4, the adder 8 is the output signal f of the delay circuit 11 and of the subtractor 9 horizontally and vertically contour corrected r times by the amplifier 4. The output signal i is added to output the same signal as the final output signal j. Therefore, by constructing the image of the television by the horizontal and vertical contour corrected image signal such as the signal of FIG. 4 (j), the clear portion of the image is brighter and the dark portion of the image is darker, so that the image quality is improved.

이다.In the above-described operation of the present invention, the waveform of FIG. 4 is expressed by the following equation. When the input signal is displayed as Y and the current input signal is sequentially input as Y _n-2 , Y _nl , and Y _n according to the horizontal period, the delay circuit 11 when the waveform input to the delay circuit 11 is Y _n. The output waveform of) is Y _n-1, and the waveform output through the adder 5 and the amplifier 1 is

to be.

On the other hand, the expression of the output waveform g of the amplifier 2 is

The equation of the output waveform h of the low pass filter 10 is

In addition, the expression of the output waveform i of the subtractor 9 is

The formula of the output waveform j of the adder 8 which is the final output is

According to the circuit of the present invention operating as described above, the horizontal contour correction is performed at the portion where the brightness of the video signal is changed as shown in waveform (j) of FIG. 4 and the vertical contour correction is performed at the portion where the brightness of the video signal is constant. Since two-dimensional image outline correction can be performed to provide a clearer image quality than before, the present invention is applied to a video signal processing system of a television and a luminance signal output terminal of a video tape recorder to correct an image. It has the effect of improving the quality of the product to have a screen.

Claims (1)

An outline correction circuit of a television video signal processing system that corrects the outline of an image by adjusting a luminance signal, comprising: a delay circuit 11 for delaying an input video signal by one horizontal period and an input / output signal of the delay circuit 11; An adder 5, a delay circuit l2 for delaying the output signal of the adder 5 by one horizontal period, an adder 6 for adding an input / output signal of the delay circuit, a delay circuit 11, and an adder 6; An adder 7 for adding an output signal, a low pass filter 10 configured at the output of the adder 7, and a subtractor 9 for subtracting the output signal of the low pass filter 110 from the output signal of the delay circuit 11; ), An adder 8 for adding and outputting the output signal of the delay circuit 11 and the output signal of the subtractor 9, and a signal attenuation amplifier configured at the output terminals of the adders 5, 6, and 7, respectively. 1,2,3) and an amplifier for adjusting the amplification factor 4 configured at the output of the subtractor 9, 2D image contour correction circuit, characterized in that.

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