Researches On Image Coding System For Image Communication

In the system of the digital image communication, it is essential to have an compression algorithm with higher performance to compress the huge digital video data because of the finite channel. So the study of the image coding system is very practical. In recent years, wavelet transform has have success in the image coding, ADV6 11 developed by Analog Devices is a kind of image coding chip based on it. In the paper, an image coding system was developed which is used in wireless image transmission based on the ADV6II, ADSP2185 is served as the control CPU in the system. The system can support PAL and NTSC's analog video, the sampled digital video accords with the CCIR-601 standard. The compressed video bit rate can be adjusted from 9600bps to 6.144Mbps, the field rate can be adjusted from I fieldl2s to 60 fields/s. It also supports QQCIF, QCIF, CIF, Full image resolution. The system resolves the video compressing question in digital video communication system.At the same time, an image coding algorithm with the region of interests was introduced, called Embedded Zeotree Wavelet with region of interests (EZW_ROl). which is based on the EZW. EZW_ROI encodes the image with a better quality inside the region of interests, and does it with a low-grade quality in the unimportant region (outside the region of interests). The result of the experiment shows EZW_ROI has better vision effect than EZW under the high compressed ratio.