IMAGE CODING METHOD AND DEVICE THEREFOR

摘要

PROBLEM TO BE SOLVED: To encode efficiently a page description language(PDL)/scan-in mixed image by a single coding method. SOLUTION: A window processing means 1 segments a coding object pixel value and a peripheral pixel value group 8 from received image data 7 and provides an output of them. An approximation means 2 approximates a coded object pixel from the peripheral pixel value group 8 by a plurality of methods and provides an output of the approximated result as a decoding pixel value object group 9. An approximation method selection means 3 calculates an error between the decoding pixel value object group 9 and the coded object pixel and selects a predictor providing a minimum prediction value in a least sequence among a group of predictors taking a pixel value of one pixel itself to be a predicted value with an error of 0. When not, the approximation method providing a minimum error is selected. The selected predictor and approximation method are outputted as an approximation method index 10 and symbolized by a sequence/run length calculation means 4. Then they are huffman-coded and outputted.