IMAGE COMPRESSION AND EXPANSION METHOD BASED ON JPEG USING WAVELET TRANSFORM

摘要

PURPOSE: A method of compressing and decompressing a still image is provided to maximize the smoothness of the pixel values of input image and to compress or decompress chrominance information with high fidelity by performing wavelet transformation in advance. CONSTITUTION: An input video signal is Daubechies wavelet-transformed(302). The low frequency component of the transformed video signal is JPEG-encoded(303), and the high frequency component of the transformed video signal is compressed by Huffman-coding method(304). Then the low-frequency component of the compressed video signal is JPEG-decoded(305) and the high-frequency component of the signal is Huffman-decoded. The decoded video signal is inverse-wavelet transformed to restore video(306).