Apparatus for enhancing digital image luminance contrast

Abstract

The invention provides a digital image brightness contrast enhancement device. The device comprises a brightness information statistics module, a first delay module, a second delay module, a third delay module, a fourth delay module, a brightness projected curve generation module, an interfield brightness relationship judgment module and a brightness control module. The image is divided into three parts for adjustment according to the brightness, and can be adjusted according to the brightness distribution characteristics of different brightness areas, and not only the contrast of the entire image is well promoted, but also the distortion caused during the process of adjusting the position where the adjustment is not required is avoided; the realizability of the hardware is considered at all time during the realization, the complexity is reduced, and the storage space is saved, therefore, the invention is convenient for being integrated to the chip; and in addition, the device further comprises an approximate saturation computation module and a fifth delay module, and the adjustment effect of the contrast control device to the colorful image is better with the consideration of image saturation.

Description

technical field [0001] The invention relates to a digital video signal processing device, in particular to a digital video signal enhancement processing device. Background technique [0002] In today's information age, people have higher and higher requirements for the display of video images. In many current digital video systems, in addition to making great improvements in the signal-to-noise ratio and resolution of video signals, there are also many developments for human The method of improving image quality based on visual characteristics of the eye effectively improves the display quality of video images from the aspects of enhancing image brightness, contrast, and clarity. [0003] Generally speaking, the enhancement processing of video images does not increase the inherent information content in video data, nor does it require its mathematical modeling, but processes a given image sequence to improve its image quality on a display medium. appearance. It is often ve...

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Problems solved by technology

[0006] In the U.S. patent US6826310 applied for on May 20, 2003, an automatic contrast enhancement method is proposed, which uses the histogram to count the brightness characteristics of the image, and selects an S-curve with a certain radian as the contrast adjustment method of the brightness mapping curve. The method selects different curves for different brightness characteristics, and the adjustment of the image is more in line with the actual situation. However, since the realization of the curve is realized through a lookup table, accessing the curve of the entire brightness range not only consumes a large amount of storage space, but also when a When the luminance characteristics of different luminance areas of an image are different, only one S-curve is not flexible enough.

[0007] In the U.S. patent US6463173 filed on October 30, 1995, a contrast enhancement system and method based on image histogram was proposed, which divided the histogram of the image into multiple segments, and stretched the histogram of each segment to adjust the image's contrast. Contrast, this method can be adjusted separately according to different brightness feature segments of the image, and the effect is better, but it does not use the method of curve mapping, and directly performs histogram equalization, which is not suitable for the implementation of hardware code, and is very complicated

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