Image Compression Based on Integer Lifting Wavelet Transform and Improved SPIHT
Ruan Hua · Jisuanji fangzhen · 2009
In view of the problems of complicated convolution process of wavelet transform,repeated calculations,a large number of memories,and unconsidered human visual special of SPIHT algorithm,a new image compression algorithm based on integer lifting wavelet transform and improved SPIHT is proposed.At first,image is decomposed by using 9-7 tap integer lifting wavelet.Secondly low frequency sub-image significant wavelet coefficients are specially treated.Scanning mode of high frequency ones are changed to obtain the biggest coefficient and according to the frequency-priority to export the coefficients.Meanwhile,due to introducing the idea of minimum exported bit and max value table,the algorithm has the advantages of saving time of index,economical memory,fast computation and simple encoding(or decoding).Experiments demonstrate that the PSNR value is higher and time of encoding(or decoding) is less than that of the original SPIHT at the same bit rate(specially at low bit rate).It is an effective fast image compression method.