Evaluation of JPEG Compression by Using SCID Image

This paper reports evaluation results of JPEG image compression when its technology is applied to high quality images used in printing industries. Project for evaluation (chair: Furuta) had been organized by Nibon Insatsu Sangyou Rengoukai. SCID images were used for test image data. A time needed to transfer A4 size image by usual process may be more than 10 hours for 9600 bps and one hour for 64k bps channel. In this evaluation work, relationship between quantization table values, compression ratios and qualities of reconstructed final images has been investigated. Results indicate that (1) approximately 1/10 compressed image has comparable quality to the original image, and (2) compression ratio depends deeply on the density distribution of original image data. Also, transfer speed of less than one minute for SCID image data has been achieved by using 64k bps ISDN channel and high performance codes.