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专利名称：Method and apparatus for real-time lossless
compression and decompression of imagedata
发明人：Sean M. Callahan申请号：US08/368337申请日：19950104公开号：US057968A公开日：19980818
摘要：A method and apparatus for lossless compression and decompression of videoimage data. Video data is comprised of the RGB, YUV or gray scale (color) information foreach pixel of each frame of the video data. Storage of such video data can require largeamounts of data. The present invention provides for lossless compression anddecompression of the individual frames of video image data. Each individual frame ofvideo image data is processed in n×n pixel blocks. The combination of colors (called thecolor list) and the number of different colors in the pixel block is then determined. If thenumber of colors is above a predetermined threshold, no compression occurs. If thenumber of colors is below a predetermined threshold, searches for prior occurrences ofthe combination of colors is than performed. In some instances, a color list forcontiguous pixel blocks will be the same. In this instance, a pixel map representing thepositioning of the colors in the pixel block is output. Further, each encounteredcombination of colors is stored as an entry in a color cache. The color cache is
subsequently used as a color combination dictionary. In such instances of a pixel blockwhere its color list is in the color cache, an index to the entry into the color cache is used
to represent the colors found in the pixel block. The color cache need not be stored withthe compressed data stream since it is reconstructed during decompression of thecompressed data stream.
申请人：APPLE COMPUTER, INC.
代理机构：Blakely, Sokoloff, Taylor & Zafman
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