KR100589847B1 - Apparatus for revision as to video picture quality in audio/video system - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video quality correcting apparatus of an audio / video system that adjusts a luminance signal separated from an NTSC composite signal to correct a video screen more clearly and clearly. The present invention relates to a luminance separated from an NTSC composite video signal. A first limiter for firstly limiting the level of the signal, a luminance signal differentiator for differentiating the luminance signal through the first limiter, a second limiter for secondarily limiting the level of the luminance signal output from the luminance signal differentiator, the separated A low-pass filter for low-pass filtering the luminance signal, a luminance signal emphasis unit for adding the luminance signal obtained in the low-pass filter and the differential luminance signal obtained in the second limiter, amplifying the signal to a predetermined level, and outputting it as a highlighted luminance signal; Emphasis is placed on improving video quality.

Description

Apparatus for revision as to video picture quality in audio / video system}             

1 is a block diagram of a video quality correction apparatus of an audio / video system according to the present invention;

Fig. 2 is a waveform obtained by dividing an NTSC composite signal waveform and its composite signal into luminance, synchronization, and color signals according to the present invention.

2A is an NTSC composite signal waveform diagram;

2B is a luminance signal waveform diagram separated from an NTSC composite signal;

2C is a waveform diagram of a synchronization signal separated from an NTSC composite signal;

2D is a color signal waveform diagram separated from an NTSC composite signal;

3 is a waveform diagram for explaining a difference in luminance signal for an image in the present invention;

3A is a waveform diagram of NTSC normalization;

3B is a waveform diagram of a soft image;

3C is a waveform diagram of an image emphasizing an NTSC normalized image;

4 is a frequency characteristic diagram of each luminance signal.

<Explanation of symbols for the main parts of the drawings>

10: first limiter

20: luminance signal differential

30: second limiter

40: low pass filter

50: luminance signal emphasis

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to video quality correction in an audio / video system (A / V system), and more particularly, to an apparatus for correcting video quality of an audio / video system to correct a video screen more clearly and clearly by adjusting a luminance signal.

In general, in an audio / video system, the image quality of a video screen is determined by a video signal output from a corresponding video device.

That is, a general audio / video system displays a video signal, which is reproduced or received externally, on a screen after being processed by a general video signal processing method.

In this case, there is a slight difference in image quality depending on the performance of the video device, the difference in the image quality is small, and to obtain a better image quality, a separate luminance signal or color signal correction device is required.

Therefore, the present invention is to obtain a good picture quality by adding a simple picture quality correction device to a general audio / video system,

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus for correcting video quality of an audio / video system by adjusting a luminance signal to correct a video screen more clearly and clearly.

The present invention (apparatus) for achieving the above object,

A first limiter for firstly limiting the level of the luminance signal separated from the NTSC composite video signal;

A luminance signal differentiator for differentiating the luminance signal through the first limiter;

A second limiter for second-limiting the level of the luminance signal output from the luminance signal differentiator;

A low pass filter for low pass filtering the separated luminance signal;

And a luminance signal emphasis unit which adds the luminance signal obtained by the low pass filter and the differential luminance signal obtained by the second limiter, amplifies the signal to a predetermined level, and outputs the luminance signal.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention according to the technical spirit as described above in detail.

1 is a block diagram of a video quality correction apparatus according to the present invention.

As shown, a first limiter 10 for firstly limiting the level of the input luminance signal; A luminance signal differentiator 20 for differentiating the luminance signal through the first limiter 10; A second limiter (30) for second-limiting the level of the luminance signal output from the luminance signal differentiator (20); A low pass filter 40 for low pass filtering the input luminance signal; And a luminance signal emphasis unit 50 for adding the luminance signal obtained from the low pass filter 40 and the differential luminance signal obtained from the second limiter 30, amplifying the signal to a predetermined level, and outputting the amplified luminance signal.

The operation of the video quality correction apparatus according to the present invention configured as described above is as follows.

First, the video signal used in the present invention is a National Television System Committee (NTSC) composite signal as shown in FIG. 2A, which is a luminance signal, a synchronization signal, and a color signal. Is the synthesized signal. That is, when the NTSC video signal is separated, the luminance signal as shown in Fig. 2B (signal representing the contrast of the screen is indicated by the Y signal), and the synchronization signal as shown in Fig. 2C (signal for determining the position of the screen, usually SYNC. 2D), and a color signal as shown in Fig. 2D (displayed with a C signal as a signal representing the color of the screen).

The present invention corrects video quality by using the luminance signal separated from the NTSC composite signal as described above.

To this end, the first limiter 10 first restricts the level of the input luminance signal to the set band as shown in FIG. 2B, and the luminance signal differential 20 differentiates the band limited luminance signal. The differential signal is transmitted to the luminance signal emphasis unit 50 after the second limit is once again limited to the set band in the second limiter 30.

Meanwhile, the low pass filter 40 performs low pass filtering on the luminance signal input as described above to the set band, and the low pass filtered signal is input to the luminance signal emphasis unit 50.

The luminance signal emphasis unit 50 emphasizes the luminance signal by mixing the original luminance signal low-pass filtered by the low pass filter 40 and the differential signal obtained by the second limiter 30.

Here, the emphasis refers to compensating an image more clearly or flexibly with respect to a standard screen.

For example, FIG. 3A is a luminance signal synthesized with an NTSC standard video signal, and FIG. 3B is a luminance signal synthesized with a soft image. The luminance signal emphasis method according to the present invention emphasizes the standard luminance signal as shown in FIG. 3A. In this case, the luminance signal waveform as shown in FIG. 3C can be obtained, and the image quality can be improved by the emphasized luminance signal.

Fig. 4 shows the frequency level (a) of the standard luminance signal and the frequency level (b) of the roughly highlighted luminance signal for sharpening the screen and the frequency level (c) of the luminance signal with flexible luminance signal for the flexible display. It is a graph.

Therefore, by the luminance signal emphasis apparatus as in the present invention, the luminance signal is corrected so that the luminance signal is at the same frequency level as in FIGS. 3C or 4B and 4C, thereby improving the quality of the displayed screen.

As described above, the present invention has the effect of improving the image quality by emphasizing the luminance signal, and also has the advantage that the image quality can be flexibly or sharply obtained by the selective emphasis of the luminance signal.

Claims (1)

In an audio / video system for playing audio and video, A first limiter for firstly limiting the level of the luminance signal separated from the NTSC composite video signal; A luminance signal differentiator for differentiating the luminance signal through the first limiter; A second limiter for second-limiting the level of the luminance signal output from the luminance signal differentiator; A low pass filter for low pass filtering the separated luminance signal; And a luminance signal enhancement unit which adds the luminance signal obtained from the low pass filter and the differential luminance signal obtained from the second limiter, amplifies the signal to a predetermined level, and outputs the luminance signal as a highlighted luminance signal. Image quality correction device.

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