Improvements of SPIHT in Image Compression- Survey

Set partitioning in heirarichal trees (SPIHT) is a widely used compression algorithm for wavelet transformed images. Of most algorithms developed, SPIHT algorithm ever since its introduction in 1996 for image compression has received a lot of attention. Though SPIHT is much simpler and efficient than many existing compression techniques as it’s a fully embedded codec , provides good image quality, high PSNR, optimized for progressive image transmission, efficient combination with error protection, sort information on demand and hence requirement of powerful error correction decreases from beginning to end but still it has some drawbacks which need to be removed for its better use so since its evolution it has undergone many changes in its original version. This paper presents a survey on various improvements in SPIHT in certain fields as speed, redundancy, quality, error resilience, complexity, memory requirement and compression ratio.