Lossy Compression Schemes Based on Transforms-A Literature Review on Medical Images

Abstract

In recent years, advances in information technology and telecommunications have played a crucial role as catalysts for significant developments in the sector of healthcare. These technological advances have played a very strong role in the field of medical imaging. The number of digital m edical images has increased rapidly on the Internet. The necessity of fast and secure diagnosis is vital in the medical world.The purpose of medical image compression is express medical images with less data so that it can be efficiently stored and transm itted. Diagnosis is effective only when compression techniques preserve all the relevant and important image information needed. There are basically two types of image compression: lossless and lossy. Lossless coding does not permit high compression ratios where as lossy achieve high compression ratio. Among the existing lossy compression schemes, transform coding is one of the most effective strategies. This paper summarizes the different compression methods based on transforms like Discrete Cosine Transform(DCT), Discrete Wavelet Transform(DWT), Hybrid DCT -DWT and Contourlet transform. And it has been analyzed that Contourlet transform have superior overall performance over other transforms in terms of PSNR.