05796864 is referenced by 100 patents and cites 17 patents.

A method and apparatus for lossless compression and decompression of video image data. Video data is comprised of the RGB, YUV or gray scale (color) information for each pixel of each frame of the video data. Storage of such video data can require large amounts of data. The present invention provides for lossless compression and decompression of the individual frames of video image data. Each individual frame of video image data is processed in n.times.n pixel blocks. The combination of colors (called the color list) and the number of different colors in the pixel block is then determined. If the number of colors is above a predetermined threshold, no compression occurs. If the number of colors is below a predetermined threshold, searches for prior occurrences of the combination of colors is than performed. In some instances, a color list for contiguous pixel blocks will be the same. In this instance, a pixel map representing the positioning of the colors in the pixel block is output. Further, each encountered combination 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 block where 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 with the compressed data stream since it is reconstructed during decompression of the compressed data stream.

Title
Method and apparatus for real-time lossless compression and decompression of image data
Application Number
881770
Publication Number
5796864
Application Date
January 4, 1995
Publication Date
August 18, 1998
Inventor
Sean M Callahan
Cupertino
CA, US
Agent
Blakely Sokoloff Taylor & Zafman
Assignee
Apple Computer
CA, US
IPC
G06T 9/00
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