Patent ID: 6069977
Filing Date: 2000-05-30
Classification: H04N

Abstract:
An image compression method which uses a wavelet transform technique and which converts an input image into coded data of an output compressed image, comprising the steps of:(a) inputting said input image and obtaining transform coefficients by transforming said input image in accordance with said wavelet transforming technique;(b) determining a quantizing interval which minimizes quantization errors in a predetermined step size, wherein said quantizing interval is determined according to statistical characteristics of said input image;(c) generating a simple tree structure based on said transform coefficients;(d) modifying said simple tree structure by using statistical characteristics of said transform coefficients to produce a monotonically decreasing tree structure, wherein said monotonically decreasing tree structure comprises a parent node and child nodes which correspond to said parent node;(e) modifying said monotonically decreasing tree structure by limiting a maximum height difference between said parent node and said child nodes to produce a modified tree list;(f) quantizing said transform coefficients based on said quantizing interval to produce quantized transform coefficients; and(g) arithmetically coding said modified tree list and said quantized transform coefficients to produce said coded data, wherein said coded data corresponds to said output compressed image.