Hybrid Image Compression Scheme Based on PVQ and EVQ

• Main Authors: Chia Liang Liu, 劉家良
• Other Authors: 張世旭
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/91423278776285614954

碩士 === 大葉大學 === 資訊工程學系碩士班 === 93 === The image compression is used to vector quantization. It has not considered the relation between the image blocks, so we could be able to improve the bit rate. In this paper, we propose a predicted coding scheme based on VQ algorithm, prediction algorithm, and error VQ algorithm. The prediction algorithm is used to encode smooth blocks. Otherwise VQ and EVQ are used to encode edge blocks, respectively. The scheme not only improves the image quality of decompressed but also has low bit rate than VQ algorithm. The experimental results show that our scheme performs better than VQ algorithm. For example, the test image “Lena” achieves 35.02 dB of reconstructed image quality at 0.87 bpp. And “Lena” achieves 31.07 dB of reconstructed image quality at 0.31 bpp than VQ algorithm high 0.71 dB at 0.625 bpp. It is obvious that our proposed PVQ-EVQ scheme not only has high compression rate, but also has good reconstructed images quality. Keyword：VQ, Prediction, Hybrid image coding, PSNR