초록 ▼

A method for compression and decompression of image data. The data is received as an initial image at an encoder. The encoder compresses the data by performing a spatial frequency decomposition on the image data, modifying selected frequency band images produced by the decomposition by applying a no

A method for compression and decompression of image data. The data is received as an initial image at an encoder. The encoder compresses the data by performing a spatial frequency decomposition on the image data, modifying selected frequency band images produced by the decomposition by applying a non-linear transformation, quantizing the results and compressing them into a bit stream. The data is then transmitted to a decoder that reverses the process.

대표청구항 ▼

1. A method for compressing and decompressing image information, comprising the steps of:a) receiving initial image data at an encoder; b) performing a spatial frequency decomposition upon said image data, thereby producing frequency band images having positive and negative coefficients; c) modifyin

1. A method for compressing and decompressing image information, comprising the steps of:a) receiving initial image data at an encoder; b) performing a spatial frequency decomposition upon said image data, thereby producing frequency band images having positive and negative coefficients; c) modifying selected ones of said frequency band images, wherein modification is performed with a nonlinear function, wherein the nonlinear function has a sigmoidal shape with respect to the positive and the negative coefficients, thereby producing non-linearly transformed coefficients; d) performing quantization upon said non-linearly transformed coefficients into a compressed bit stream; e) receiving said compressed bit stream at a decoder, thereby producing decompressed non-linearly transformed coefficients; f) decoding the decompressed non-linearly transformed coefficients by adjusting them with the inverse of the sigmoidal nonlinear function, thereby producing decoded and adjusted coefficients; g) inverting the decoded non-linearly transformed coefficients back to the spatial domain using these decoded and adjusted coefficients, thereby producing a full-bandwidth, decompressed image.