Method of compressing digital images

摘要: A method of compressing digital representations images stores the in multiple subsampling quality scales a progressive manner such that higher scale contains only data incremental to an adjacent lower scale. The each is transformed, quantized, and entropy encoded. discrete wavelet cosine transformation combining frequency features spatial provided. Sequences are provided for multi-scale images. novel context selection used which treats color components coefficients different positions differently. An image compressed given can be transmitted or decompressed progressively allowing downloading transmission over Internet.