Implementation of prioritised ROI coding for medical image archiving using JPEG2000

Recently, medical imaging has increased its importance greatly in picture archiving & communication (PACS). Many current compression schemes provide a very high compression rate but with considerable loss of quality. On the other hand, in some areas of image processing, in particular medical images, it may be sufficient to maintain high image quality only in the region of interest, i.e., in diagnostically important regions. ROI coding used in JPEG2000 (2002) has the capability of encoding a restricted region in an image prior to its background (BG) region. Its coding paradigm is based on the embedded block coding with optimised truncation (EBCOT) algorithm. In this paper, we propose an efficient, region-of-interest (ROI) coding scheme achieved by modifying the conventional ROI encoding method. This method implements a prioritized double ROI that adds an additional feature of viewing diagnostically significant (diseased region) and diagnostically insignificant but visually important surrounding region (region prone to infection).This requirement has been out looked in JPEG2000. From our experimental results it has been observed that there is a phenomenal increase in the compression efficiency in terms of bits per pixel (bpp) and PSNR compared to conventional JPEG2000 ROI.