Design Of Intra Frame Compression Method And Practical Program In Videoconference System

With the development of information technology, people are not satisfied with old communication styles. Under the environment, a series of application of new multimedia technology comes forth such as video conference, video telephone and so on. To do work more efficiently, Ministry of Communications decided to implement Multimedia Videoconference System on LAN. The design of an Intra frame compression method and program of this project is discussed in the thesis.Intra frame, on the earth, is still picture. There are many compression methods of still picture, for example, DPCM, Vector Quantization, Block Transform Coding, Fractal Coding, ANN Coding and Wavelet Transform Coding etc. Among these DCT coding, as a kind of Block Transform Coding, is the most used and mature one. But the method focuses less on high-frequency component. As a result, large edge distortion is led. Dr. Liu Chunyang in Xi'an Jiao Tong University studied the response relationship between image edge and its DCT spectrum distribution and found that directional edge also has directionality in its DCT spectrum distribution. And human eyes are just most sensitive to directional edges. Based on these conclusions, he designed a new quantization coding method, which is called Image Coding Based on 2-Dimensional DCT Spectrum Distribution Analysis.This thesis discusses this still image compression method and the design of Intra frame compression method and program. The Intra frame compression method also abstract data by move-mask designed on spectrum distribution feature line. Moreover there is some improvement:(1) Colorful images compression and reconstruction;(2) The simplification of mask design with spectrum distribution feature line; (2) The further study of mask design without spectrum distribution feature line.