Vision signal contrast intensifier

Abstract

The present invention relates to a contrast enhancing apparatus for a video signal which is capable of enhancing a coefficient characteristic of a light and dark portion of a video signal in a video display apparatus such as TV, etc. In the present invention, the coefficient which is varied based on the levels of the high frequency component and low frequency component for enhancing the low frequency component separated from the video signal, and the low frequency level is compensated with the thusly determined coefficient, and a coefficient which is in inverse proportion to the enhancement of the low frequency component. Therefore, in the present invention, it is possible to enhance the contrast based on the video signal which is inputted in real time by uniformly varying the enhancing coefficients of the high frequency component and the low frequency component based on a user control signal.

Description

technical field [0001] The present invention generally relates to a video signal contrast enhancement device, in particular to a contrast enhancement device capable of significantly enhancing the contrast of a video signal by enhancing (amplifying or attenuating) the input video signal. Background technique [0002] In a method for enhancing the contrast of a video signal, the contrast of the video signal is enhanced by selecting a boundary portion of the video signal and enhancing it. In another method, contrast is enhanced by using a homomorphic filter to enhance the light-to-dark ratio between bright and dark parts. [0003] As shown in Figure 1, the video signal contrast enhancement device composed of a conventional homomorphic filter includes: an algebraic transformation unit 100, which is used to transform the video signal Yin into an algebraic form (log); a filtering unit 200, which is used to transform the algebraically transformed The video signal Ylog1 of the vide...

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Problems solved by technology

However, since the above-mentioned coefficients "a" and "b" have fixed values, all video signals will be amplified or attenuated by a fixed factor, so it cannot properly enhance the contrast of all video signals

[0008] Furthermore, in the method in which the coefficients "a" and "b" are set to different values ​​according to the video signal Yin, it is difficult to be suitable for real-time processing, and in the case of attenuating the low-frequency component Ylpf1, since a DC voltage The phenomenon of flat transition, so the final output Yout must be scaled again, and the minimum and maximum values ​​​​of the signal components must be obtained, so that it will not be able to achieve real-time processing

[0009] Since the video signal cannot be processed in real time, it will not be able to uniformly enhance the contrast of the video signal

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