A COMPARISON OF LOSSLESS COMPRESSION METHODS FOR MEDICAL IMAGES

In this work, lossless grayscale image compression methods are compare d on a medical image database. The database contains 10 different type s of images with bit rates varying from 8 to 16 bits per pixel. The to tal number of test images was about 3000, originating from 125 differe nt patient studies. Methods used for compressing the images include se ven methods designed for grayscale images and 18 ordinary general-purp ose compression programs. Furthermore, four compressed image file form ats were used. The results show that the compression ratios strongly d epend on the type of the image. The best methods turned out to be TMW, CALIC and JPEG-LS. The analysis step in TMW is very time-consuming. C ALIC gives high compression ratios in a reasonable time, whereas JPEG- LS is nearly as effective and very fast. (C) 1998 Elsevier Science Ltd . All rights reserved.