Studies Of Digital Image Enlargement Technology And Development Of Video Wall System Controller

Large screen, high definition and digital display are the technology tendencies in today's display domain. So the research for image enlargement technology becomes more and more important. In addition, multi-screen display system ?"Video Wall System" is one of most important popular ways for large screen display. Our Lab 502 has successfully researched and developed out a high luminance, high definition and large screen YAG rear-projector. It is outstanding in today's display devices, has been awarded the second scale of Chinese science and technology invention award. We have made a 3x3 video wall system by our YAG rear-projector too. Among the signal processing devices of a video-wall system, the most important part is the "Video Wall Controller". In this paper, I have studied the traditional and new image enlargement technologies, and then put forward two new enlargement ways for video wall display system. And after hard work, we have made out a video wall controller which can run for 2 X 2, or 3 X 3 enlargement.According to the text order, the most important parts of my work and my innovational points can be summarized like these:1. Studied and proofed the relationship between the continuity of the interpolation spline function's derivative and its low-pass respondence in frequency domain. That is, we have try to answer the question: Why do we need to design a spline function with second order continuity of its derivative? And denied the way to get a interpolation-operator by theory and experiment, which just simply cuts out and samples the Sinc function.2. Redefined the exchanged-interpolation-operator. Let all interpolation arithmetic can be compared and studied by the operator tools. Discussed mostly all fields of the exchanged-interpolation-operator. Presented my interpolation- operators, and explained some characters of the exchanged-interpolation-operator.3. Put forward two new enlargement ways for video wall display system. Their advantages are: can cut down the "Mosaic Effect" distinctly, and at the same time, let the image deblur, omit the gray skip which is similar with the spot noise too. So the display quality can be clearly improved. And the corresponding circuit is more simple and easy to make than the bilinear interpolation arithmetic. Can both work well in the traditional TV display and today's computer monitor display. They have a good potential economical benefit.4. Analyzed the restraining effects of the median filter to the noise in an enlargedimage, and got some qualitative and some quantitative results. Studied the "root signal effects" of the median filter to an enlarged image. Compared the influences in different enlargement arithmetic brought by the median filter, the results are summarized in five theories.5. Discussed a new way to judge an image with the "entropy". It can judge an image which has been enlarged by any arithmetic. A rule has been found and should be obeyed, that is, "the entropy of the new data should close the entropy of the old data as much as it can."6. Made out a video wall controller which can work for 2 X 2, or 3 X 3 image enlargement.