Research Of LCD Color Restoration

With the rapid development of computers, LCD (Liquid Crystal Display) and LCD TV are becoming an important and a necessary part in people's entertainments and office life. Compared with CRT, LCD has many virtues such as smaller volume, lighter weight, higher definition, etc., and interests people much. But LCD was born with many congenital deficiencies, and worse color restoration is an obvious one. This congenital deficiency restricts LCD development seriously. To solve this problem has become an important task in the LCD development road. Due to the complexity of LCD color restoration, the technology how to improve the LCD color restoration ability still exist a huge development space.Recently, due to the perfect color display, Display industry lets the CRT display gamut be a standard gamut and make other display system come close to CRT's. Considering this and the display system tricolor properties, we transform the color image from RGB color space to CIEXYZ color system to satisfy the color compatibility of different display system. On promise of unchanged of the LCD tricolor properties, map the LCD's gamut to CRT's to extend LCD's gamut. And then correct three channels with naturalness index and colorfulness index non-linearly and make it satisfy the natural color adaptation of human visual system.According to the different demand to color display, this paper modifies the luminance, contrast and the saturation components in the display system, and users can adjust and control the color display through parameters to satisfy themselves.Based on the research of color image enhancement algorithm, we modify the luminance, contrast and saturation component with different algorithm according to their different contribution of a color image. To luminance component, we propose an adaptive enhancement algorithm based on the saturation feedback and the human visual properties. Experimental data show that enhanced image luminance improves a lot without reducing the color saturation and obtain better visual effect. To contrast, we propose an algorithm based on the space frequency of four directions and calculate the contrast improve rate. The processed color image has higher contrast with more clear details. However, to saturation, we compute the most saturation of a color image pixel in the CIEXYZ color space and then calculate the saturation of every pixel. At last, extend its dynamic range by non-linear stretch. The results show that the processed color image has more colorful color, higher clear edges without "cloud mud".Each algorithm proposed in this paper is realized using Matlab language. In the experiment, we process 67 different color images and compare proposed algorithm with traditional algorithm and other algorithm. Experimental data show that enhanced images with proposed algorithm in this paper have improved much a lot no matter in details aspect, in contrast aspect or in color aspect, and have clearer details, sharp edges, higher contrast, more colorful color and better visual effect compared with the original images and the processed images with other methods. Besides, the gamut of the enhanced image becomes larger than the original image. Apply proposed color image enhancement algorithms in this paper to LCD image process unit, the LCD color restoration ability can be improved obviously and obtain perfect color image display.