An Efficient Image Compression Coding Method-Research On Improved SPIHT Algorithm

With the increasing of modern information society to business requirements, thecontradictions between image communication and the capacity of communications arebecoming increasingly prominent. The sharing of large quantity of data becomes verydifficult by digital image communications on network. It becomes the bottleneckproblems in the development of image communications. So in order to alleviate thenetwork bandwidth, increase the communication speed of image information, it isnecessary to study new image compression algorithm with high rate.This paperintroduces the image compression code for a brief, respectively discusses the needof image compression, coding methods and the coding standards. And it analyzes itsapplication in all fields, which reflects the importanceof image compression.Firstly, some popular statically image compression algorithms which includesEZW, SPECK, CREW and SPIHT are in-depth studied in this paper. The result ofstudy shows that SPIHT algorithm has better effect and outputs less bits. But forscanning the unimportant coefficients time and again in the list structure, it increasesthe burden of memory and the complex of software and hardware, which reduces theefficiency.Secondly, a improved SPIHT algorithm based on DWT is put forward for theweaknesses of SPIHT. It reduces the reading operations to memory and the burden ofmemory by the process of sorting. Through the use of a multidimensional arrayinstead of the list structure, it reduces the implementation of the complexity ofsoftware and hardware. It does not need to caculate all the elements, and only to scanthe coefficients that are greater or equal to the threshold, which reduces thecomplexity of caculating. For the image with a large number of pixels of the samevalue, it only need to code one pixel, which greatly improves the efficiency of thecoding.Finally, against the improved SPIHT algorithm, the integer lifting wavelet isused. Through a lot of experiments, the results show that the compression efficiencyof new algorithm, using DWT or integer lifting wavelet, is better than SPIHT, whichusing DWT is better than integer lifting wavelet.