Patent ID: 7076108

Claim:
A method for compressing image data comprising the steps of: color-transforming the image data to provide color-transformed data; wavelet-transforming the color-transformed data to provide a series of wavelet coefficients in different levels of wavelet transformation subbands; quantizing the wavelet coefficients which fall above a predetermined threshold value to provide a series of quantized wavelet coefficients; applying an entropy coding to the quantized wavelet coefficients to provide coded wavelet coefficients; and compressing the coded wavelet coefficients to provide compressed image data, wherein the wavelet transformation step includes determining in sequence { X 2 â¢ n + 1 = X 2 â¢ n + 1 + A â¡ ( X 2 â¢ n + X 2 â¢ n + 2 ) X 2 â¢ n = X 2 â¢ n + B â¡ ( X 2 â¢ n - 1 + X 2 â¢ n + 1 ) X 2 â¢ n + 1 = X 2 â¢ n + 1 + C â¡ ( X 2 â¢ n + X 2 â¢ n + 2 ) X 2 â¢ n = X 2 â¢ n + D â¡ ( X 2 â¢ n - 1 + X 2 â¢ n + 1 ) X 2 â¢ n + 1 = - KX 2 â¢ n + 1 X 2 â¢ n = 1 K â¢ X 2 â¢ n for lifting and scaling the color-transformed data thereby providing the series of wavelet coefficients, where X is one of the color-transformed data, n is a one-dimensional pixel index, A=âˆ’1.586134342, B=âˆ’0.052980118, C=0.882911075, D=0.443506852, and K=1.230174105.