wan@mercury (Shijie Wan) (04/22/91)
Color Compression Software Available ------------------------------------ A full-color image can use up to 16 million different colors. Most commonly used color monitors and laser printers can display/print only 256 or less different colors simultaneously. In order to display/print a full-color image on these devices, the number of colors in the original image must be compressed before display. We have designed a color image quantization algorithm which can reduce the colors in a full-color image to 256 colors or less with minimum distortion. Experiments show that in most cases our algorithm needs to use 128-256 colors to produce an image which looks almost identical to the original full-color image. With 32-64 colors, it can produce images of high quality. For 32 colors or less, it can generate quantized images with minimum contouring effects, with the aid of dithering techniques. For details of the algorithm and image examples, read the paper: S.J. Wan, P. Prusinkiewicz, and S.K.M. Wong, Variance-based color image quantization for frame buffer display, Color Research and Application, vol. 15 (1), pp. 52-58, Feb. 1990. The program is written in C for Silicon Graphics IRIS machine. Versions for other machines running UNIX are also available. Excluding the time for image disply, the program needs about 10-40 seconds to process one image. For more information, please contact: ---------------------------------------------------------------- | wan@mercury.uregina.ca | Shijie Wan | | Tel: (306)-584-5717 | Dept. of Comp. Sci. | | (306)-585-4690 | Univ. of Regina | | Fax: (306)-584-5717 | Regina, Sask. | | | Canada S4S 0A2 | ----------------------------------------------------------------
spencer@eecs.umich.edu (Spencer W. Thomas) (04/25/91)
This algorithm is also used in the rlequant program, part of the Utah Raster Toolkit. See the Frequently Asked Questions posting for FTP information. -- =Spencer W. Thomas EECS Dept, U of Michigan, Ann Arbor, MI 48109 spencer@eecs.umich.edu 313-936-2616 (8-6 E[SD]T M-F)