Importance

Loading Importance Indicators...

Abstract

On the image compression side, each lossless wavelet transformation coefficient on which a lossless wavelet transformation for an image is effected, is first subjected to quantization and entropy coding in a coarse step size. Thereafter, quantization error signals are successively subjected to quantization and entropy coding in a fine step size to thereby generate a progressive coded bit stream. On the image expansion side, lossless wavelet transformation coefficients obtained by entropy decoding and inverse quantization are subjected to inverse lossless wavelet transformations every coded bit streams bearing respective stages for image progressive reconstruction display. Data obtained by the inverse transformations is added to the already-reconstructed image data together with updated auxiliary information about each image to thereby reconstruct and display the image progressively. Now, the updated auxiliary information necessary to update the image is generated from some of information about lossless wavelet transformation coefficients necessary to update the image quality by one stage and some of lossless wavelet transformation coefficients necessary to generate the already-displayed image, whereby it is not necessary to hold all the information about lossless wavelet transformation coefficients necessary to generate a pre-updating image and memory's capacity can be reduced.

Loading the Abstract Image...

First Claim