Investigation on extended JPEG system in which each region in an image has its own JPEG quantization table and its application to medical ultrasonic B-mode image compression
Kazuhiko Hamamoto · IEEJ Transactions on Electronics Information and Systems · 2001
The purpose of this paper is to develop compression method for medical ultrasonic echo image which is able to keep sufficient image quality for diagnosis. There are two ideas for it. One is a method to reduce the data volume without perceived loss of image quality in all region. The other is a method in which image quality in ROI is scarcely lowered and in the other area is severely lowered. In image compression with a JPEG baseline system, it is possible to control the compression ratio and image quality by controlling quantization values. The JPEG baseline system enables a JPEG bit stream to include four JPEG quantization tables. In this proposal, I divide an image into four regions which have different characteristic each other and attempt to optimize JPEG quantization table for each region. This method is named “Extended JPEG system” Medical ultrasoinc echo images are compressed by this method on ideas mentioned above. The compressed images are evaluated by rate, PSNR and the subjective assessment of the quality of pictures.