Patent ID: 8503806

Claim:
A compression encoder for compression and coding of an image signal, comprising: a wavelet transformer configured to recursively divide an image signal into high- and low-pass components by wavelet transform and to generate and output transform coefficients in a plurality of bandpass components; an image-quality controller configured to determine a quantization step size by dividing a quantization parameter, which indicates a target image quality and is set by user input, by a norm of a filter coefficient; an entropy coder configured to entropy code said transform coefficients; and a rate controller configured to perform rate control by sorting coded data outputted from said entropy coder in predetermined order of scanning with said quantization step size to generate a code sequence and to perform truncation of part of said code sequence from lowest-order bits based on a desired level of noise reduction until a total capacity of said coded data in said code sequence meets the target image quality set by the user input, an amount of truncation becoming greater as said desired level of noise reduction becomes greater.