The Auto-transforming Of Bitmap From True-color To Index-color And Researching On Dithering Technique

The developing cause of the digital TV had been increased by the Set-Top-Box's emergence. At the same time, it also provided a new interaction operational system. In the digital TV, the image is absolutely necessary. Now, the TV display could show the 8 bit image commonly, but the image taking equipment could only obtain the 24 bit image, so the 24 bit image must be transformed to the 8 bit from the beginning, that could be show at TV naturally. After the color mode transforming of image, it could not only reduced the demand to hardware of system, but also compressed the color data. The article focused on the color mode transformation and made a large number of experiments. The main work of this article was as follows: firstly working out the project of the color mode transformation by studying on the color data characteristic of the Real-color and the Index-color, consulting the production previously; secondly, studying and experiencing on the key technologies, including the selecting of the palette and the study on the halftone technology; thirdly, putting forward the auto transformation algorithm to adapting the demand of all kinds of palettes and the dithering algorithm based on the weakened operator for improving the net-map of the Floyd-Steinberg algorithm, evaluating the result from the subjective and external aspect. The experimental results indicated that auto-transformation thought of the article was flexible and could obtain good transforming effect. The weakened algorithm weakened the net-map phenomena, improved the image quality greatly. The programs of this article were simple, and could be embedded to the Embedded System easily. The studying production had been applied in practice and obtaining better effect. The researching was a good attempting of the integrating from theory to practice.