Image Compression using Combined Approach of EZW and SPIHT with DCT

The key purpose of image compression is to reduce the size of the images. The advantages of reducing the size of the image are efficient memory usage and reduction in transit time of images through network. But we have to make sure that there is no loss in quality and intelligence of the original image, so that we can retrieve almost exactly the same original image from the compressed image. Existing two algorithms namely EZW and SPIHT are widely being used for their higher compression ratio and good PSNR. Of these two, SPIHT is preferred widely since it has higher compression ratio and better PSNR than EZW. We propose an approach where we apply DCT on compressed image from EZW and SPIHT algorithm to provide improvement in the compression ratio thereby further reducing the size of the image. We compare the compression ratio and size of the compressed image of EZW and SPIHT algorithm with our proposed technique.