IMAGE CODER, METHOD, COMPUTER PROGRAM, AND COMPUTER READABLE STORAGE MEDIUM

摘要

PROBLEM TO BE SOLVED: To reduce the image quality deterioration of coded images while reciprocative coded data and nonreciprocative coded data are mixed. SOLUTION: A first coder 102 JPEG-codes pixel blocks per unit, and a second coder 103 JPEG-LS codes them. A coding sequence controller 110 selects either of two coded data according to whether a specified nonlinear boundary function f() meets Ly≥f(Lx) and stores it in a first memory. Lx is the code length of coded data generated by the first coder 102, and Ly is that generated by the second coder 103, provided that the nonlinear boundary function f() has a down convex curve in a region below a specified coded length in both coded lengths where the abscissa takes the code length of the coded data generated by the second coder and the ordinate takes that generated by the first coder. COPYRIGHT: (C)2006,JPO&NCIPI