The Research And Implementation Of Still Image Compression Coding Techniques Based On Integer Wavelet Transform

Image contains large data, so how to compress image data has developed as a special research area-image coding. How to organize, save, transmit and restore image data effectively, i.e., how to explore more efficient and better compression rate image coding techniques has become one of important tasks in modern information processing techniques. Because of its unique characteristics, wavelet transform has been successfully applied into image compressing coding areas, and image coding techniques based on wavelet transform has become one of main tasks in image research areas.In this thesis, the introduction to the necessity, the development and the research of image compression coding techniques have been firstly made before the evaluation criteria of image compression techniques have been listed. After reviewing Fourier transform and Short Time Fourier Transform (STFT), the author introduces the definition and properties of wavelet transform. Theories such as continue wavelet transform, discrete wavelet transform, multi-resolution analysis, scale function, wavelet function, two-scale equation, and multi-resolution analysis filters and so on have been illustrated. Sequently, decomposition and composition of wavelet transform in Mallat algorithm are analyzed. Based on mentioned-above wavelet analysis theories, two-dimension biorthogonal wavelet and the implementation of wavelet transform on discrete images have been discussed.The thesis analyzes and discusses image compression coding theories and several image compression coding techniques. Based on wavelet transform: EZW, SPIHT, EBCOT, three typical coding algorithms are analyzed and compared systemically. Their strengths and weaknesses are summarized. Furthermore, the final experimental results of the three coding algorithms are revealed.The thesis puts forward a coding scheme for still images based on integer wavelet transform, combined with SPIHT algorithm and adaptive coding, and every modules of the scheme are discussed. The experimental results indicate that the scheme is available and feasible compared with other schemes. We have improved the SPIHT algorithm based on existing image compression coding algorithms, and applied the improved SPIHT algorithm into the scheme we have proposed. The experimental results indicate that the scheme with improved SPIHT can enhance image lossless compression rate effectively.