Techniques Research Of Video Preprocessing

At present, applications of video processing and communication system are rapidly growing with the rapid development of wide band network. We can anticipate that the traffic of video communication will become the important value-increasing point for telecommunication operators in the recent future years. It is the key problem of telecommunication services to improve the end-to-end user experience. As a part of video processing and communication system, video preprocessing plays a very important role to solve this problem.In this paper, the video preprocessing, which is between the CCD/CMOS sensor and the video coder are deeply researched. First of all, we showed the way of capturing video and their performances, with the CCD and CMOS sensor, then, the video preprocessing framework is analysed in detail. Finally, we introduced some important function modules in the video preprocessing framework. More attentions are payed to the gamma correction and automatic focus function.The gamma distortion is introduced by the nonlinearity of many image devices. In this paper, Based on the characteristic of gamma distoration we proposed a new algorithm—table-look algorithm. The experiments show that the image quality can be greatly improved using proposed gamma corrections method.The automatic focus technique for video cameras can maximize the high frequency components of an image by adjusting lens eg, sharp details of image. Based on above fact, a new algorithm is presented which using the walsh transform in this paper. The results show that the proposed algorithm can provide a good performance and has advantages of fast speed.