第二代小波变换构造方法的特点是:①继承了第一代小波变换的多分辨率特性;②不依赖傅立叶变换;③小波变换后的系数是整数;④图象的恢复质量与变换时边界采用何种延拓方式无关.利用了“整数经过第二代小波变换后的系数仍为整数”的特性,将第二代小波变换用于图象的无损压缩编码,并和Huffman编码、第一代小波变换压缩编码进行了比较.从比较结果来看,在能够无损重建图象的同时,第二代小波变换的压缩比要高于Huffman编码.从实验结果可以看出,将它用于医学图象的压缩编码有较好的效果.

In this paper, a new method for construction of second generation wavelet transform(SGWT) was introduced in briefly. The characteristics of SGWT are as follows: It still has the multiresolution nature as first generation wavelet, the construction is independent on Fourier transform, the coefficients after transform are integer, the performance of reconstruction of image is not influenced by the boundary conditions. Then, the second generation wavelet transform was applied to image lossless coding, according to the characteristic of integer transform of SGWT. SGWT can provide higher compression ratio than Huffman coding while it reconstruct image without lossing compared with first generation wavelet transform. The experiment results show the SGWT has exihibited excellent performance in medical image compression coding.