基于离散小波变换的改进SPIHT算法研究

Improvements of SPIHT Algorithm Based on Discrete Wavelet Transform

随着现代信息社会对通信业务要求的不断增长，图像通信与通信容量的矛盾日益突出。为了缓解网络带宽的不足、加快图像信息的传播速度，对于基于高比率的图像压缩算法的研究很有必要。目前比较流行的多级树集合分裂算法压缩效果比较好，输出的比特流较少，但是需要对内存中的数据反复的读取，且反复的在链表结构中扫描不重要系数，增加内存的负担及软硬件实现的复杂度，从而降低了编码的效率。本文针对多级树集合分裂算法的缺点提出了一种基于离散小波变换的改进的多级树集合分裂算法，通过对小波系数排序过程的调整，减少了对内存反复的读取操作，减轻了对内存造成的负担，提高了编码的效率。

With the increasing of modem information society to business requirements,the contradictions between image communication and the capacity of communications are becoming increasingly prominent.So in order to alleviate the network bandwidth,increase the communication speed of image information,it is necessary to study new image compression algorithm with high rate.some popular statically image compression algorithms.The result of study shows that SPIHT algorithm has better effect and outputs less bits.But for scanning the unimportant coefficients time and again in the list structure,it increases the burden of memory and the complex of software and hardware,which reduces the efficiency.a improved SPIHT algorithm based on DWT is put forward for the weaknesses of SPIHT.It reduces the reading operations to memory and the burden of memory by the process of sorting and greatly improves the efficiency of the coding.