Wavelet transform coding technique

An encoder/decoder system for compressing and decompressing a digitized image, comprising:

• an encoder comprising:
• means for transforming each of a plurality of blocks of pixel data into a corresponding block of subband coefficients;
• a quantizer for quantizing the subband coefficients;
• an entropy-encoder for coding the quantized subband coefficients and generating a bit stream of coded data;
• a decoder comprising:
• an entropy decoder for decoding the bit stream of coded data and generating a plurality of blocks of coefficients;
• a dequantizer for dequantizing the coefficients;
• and
• means for inverse transforming each of the plurality of blocks of dequantized coefficients into a corresponding block of pixel data.

An encoder for compressing a digitized image, comprising:

• means for transforming each of a plurality of blocks of pixel data into a corresponding block of subband coefficients;
• a quantizer for quantizing the subband coefficients;
• and
• an entropy-encoder for coding the quantized subband coefficients and generating a bit stream of coded data.

A decoder for decompressing a compressed image represented by a bit stream of coded data, comprising:

• an entropy decoder for decoding the bit stream of coded data and generating a plurality of blocks of coefficients;
• a dequantizer for dequantizing the coefficients;
• and
• means for inverse transforming each of the plurality of blocks of dequantized coefficients into a corresponding block of pixel data.

A article of manufacture having embodying a program of instructions executable by a device for performing a method of compressing a digitized image, said program of instructions comprising:

• instructions for segmenting the image into a plurality of blocks of data;
• instructions for transforming each of the plurality of blocks of data into a corresponding block of subband coefficients;
• instructions for quantizing the subband coefficients;
• and
• instructions for coding the quantized subband coefficients.