A new subsampling-based predictive vector quantization for image coding

作者：Zhu C^*

来源：Signal Processing: Image Communication , 2002, 17(6): 477-484.

DOI：10.1016/S0923-5965(02)00022-X

• vector quantization
• image compression
• prediction
• rate-distortion
• complexity

improving coding efficiency for vector quantization (VQ), e.g., reducing bit-rate attainable and increasing encoding speed, has attracted intensive attention. A new image VQ scheme of subsampling-based predictive vector quantization (SB-PVQ) is introduced for this aim, which fully exploits the neighboring-pixel smoothness in both intra-blocks and the boundary areas of inter-blocks. Firstly, all non-overlapped image blocks partitioned in an image are down-sampled two-dimensionally periodically. The sub-sampled blocks (sub-vectors) are then vector quantized with a lower-dimensional and smaller size of codebook, which will contribute to speeding up the VQ encoding and reducing the bitrate. Finally, the original image blocks are constructed with decimated pixels predicted by their intra- or inter-block neighboring subsampled pixels. It should be highlighted that in the sub-block VQ encoding, multiple-candidates scheme is employed for each input in order to find the corresponding sub-codevector that can generate the best reconstructed image block. Compared with the peripheral prediction method, the new method achieves significant improvement in terms of rate-distortion performance while maintaining comparable computation complexity.

• 出版日期2002-7
• 单位南阳理工学院