Embedded Medical Image Coding Using Quantization Improvement of SPIHT

In this paper we investigate the problem of how to quantize the wavelet coefficients in the lowest frequency subband with multi-scalar method. A new quantization implementation of efficient lossy medical image compression using the Set Partitioning in Hierarchical Trees (SPIHT) algorithm at low bit rates is proposed. First, in the higher bit plane, this algorithm only quantizes the wavelet coefficients in the lowest frequency subband. Then it quantizes other ones by uniform scalar. Experiment results have shown the proposed scheme improves the performance of wavelet image coders. In particular, it will get better coding gain in the low bit rate image coding.