Digital Video Image Coding And Compression Based On Wavelet Theory

With the development of communication technology and communication business, image information transmission has become the base service of modern communication system. But the conflict between image transmission and communication network capacity is becoming more and more serious, especially for the digital images storage and transmission. The huge data for digital images is a knotty problem for image information communication. Therefore, the effective compression coding methods for digital images are necessary, and it has become a hot problem for the modern society to study. The wavelet transform, which evolved based on Fourier analysis, offers a self-adaptive localization method for a given signal in both time domain and frequency domain. Through extension and translation options and multi-scale analyzing, it can extract helpful signal information effectively. So wavelet analysis has become a powerful tool for digital image processing and compression. This paper analyzes the features of digital images and the necessary and feasibility for images compression at first, and then makes a comparison and summarize for the traditional compression methods. This paper studies the application of wavelet theory in digital video compression, and makes some discussions on the wavelet bases selection and motion estimation and compensation in wavelet frequency domain. This paper proposes a method for motion estimation and compensation by dilation and erosion algorithm, which is an innovation in this paper. This method is an object-oriented operation. It can avoid the block artifacts caused by traditional block-based methods. At last, this paper brings forward a design scheme for a real-time video compression system based on high-speed universal DSP. The arithmetic project is mainly including frames prediction, wavelet transform, quantization coding and run-length coding. This arithmetic project is experimented on personal computer by compiling C language program, and some problems that affect compression have also been compared and discussed. The video compression system is based on TMS320VC5416 DSP, which produced by American TI Company. Its features of high operation speed, special instruction word, and pipeline structure ensure it can execute real-time video compression well. This paper analyzes TMS320VC5416 DSP features and discusses some problems for the arithmetic program implementing on it. This paper also selects chips and design structure for the other function module of the compression system. At last, it gives the block diagram for the compression system.