Image data compression employing multiple compression code tables
First Claim
1. A method for compressing image data from an uncompressed image data stream, the method comprising the steps of:
- (a) compiling and storing a plurality of compression mapping tables for converting uncompressed data representative of individual picture elements to lossless compressed data;
(b) applying at least first and second compression mapping tables from the stored plurality of compression mapping tables to subregions of an uncompressed image data stream to compress the subregions; and
(c) appending data for the compressed subregions to form a compressed image data stream.
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Accused Products
Abstract
An image data compression and decompression technique applies one or more compression code tables to optimally compress an image data stream. The compression code tables are established in accordance with anticipated image characteristics, and to accommodate different levels of variation or entropy in the image data. The image data may be divided into blocks or subregions for analysis of which of the candidate compression code tables provides the optimal compression of each subregion. The appropriate code table is selected for each subregion. The evaluation of the compression performance based upon application of each compression code table may include analysis of prediction differences or errors between predicted values for pixels of an image and the actual values for the pixels.
87 Citations
27 Claims
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1. A method for compressing image data from an uncompressed image data stream, the method comprising the steps of:
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(a) compiling and storing a plurality of compression mapping tables for converting uncompressed data representative of individual picture elements to lossless compressed data; (b) applying at least first and second compression mapping tables from the stored plurality of compression mapping tables to subregions of an uncompressed image data stream to compress the subregions; and (c) appending data for the compressed subregions to form a compressed image data stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for compressing image data, the method comprising the step of:
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(a) defining a family of compression code tables for converting uncompressed image data to lossless compressed data; (b) storing the compression code tables in an image data compression station and in an image data decompression station; (c) selecting at least two of the compression code tables for compression of subregions of an image data stream; (d) compressing the image data stream in accordance with the selected compression code tables at the compression station for decompression at the decompression station. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A system for storing, transmitting and viewing images, the system comprising:
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a data compression station configured to store a plurality of compression code tables for conversion of uncompressed image data representative of individual picture elements to lossless compressed image data and to execute a compression routine in which an image data stream is converted to a compressed file by dividing into subregions and each subregion compressing in accordance with a compression code table selected from the plurality of compression code tables based upon which compression code table provides optimal lossless compression of the subregion; a data storage device for receiving and storing the compressed file; and an image decompression station configured to store the plurality of compression code tables, to access the compressed file from the data storage device, and to execute a decompression routine in which the compression code tables applied to compress the image data stream are applied to decompress the compressed file to reconstruct the image data stream. - View Dependent Claims (19, 20, 21, 22, 23)
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24. A computer readable medium storing a computer program for compressing image data, the program comprising:
configuration code and a plurality of compression code tables stored on the machine readable medium, the configuration code including an algorithm for analyzing an image data stream, for compressing subregions of uncompressed image data representative of individual picture elements in the image data stream by application of a plurality of compression code tables, and for compiling the compressed subregions into a lossless compressed data file. - View Dependent Claims (25, 26, 27)
Specification