Bit-map decompression
AssigneeXerox Corporation
InventorsStephen M. Kroon, Paul W. Philippi
Life of this patent
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Abstract
Writing a decompressed bit-map cell in accordance with a pixel count and a fill order pattern based on half-tone threshold values of a half-toned bit-map compression cell that was used to determine the pixel count.
Claims6
A method of processing a half-toned bit-map that was produced using a half-tone cell having more than N pixels, comprising:
- partitioning the half-toned bit-map into a plurality of N-pixel compression cells;
- storing for each compression cell a respective pixel count of pixels that are in a predetermined state in each compression cell;
- respectively associating a plurality of N-pixel decompressed cells of a decompressed bit map with the plurality of N-pixel compression cells, each decompressed cell having an associated fill order pattern of fill order values that are based on half-tone threshold values for corresponding pixels of the associated compression cell, wherein the decompression fill order values are between 0 and N−1;
- and
- writing pixels of the decompressed bit-map in accordance with the pixel counts and the decompression cell fill order patterns.
A method for decompressing a compressed bit map containing a plurality of pixel counts respectively associated with a plurality of N-pixel compression cells of an uncompressed half-toned bit-map that was produced using a half-tone cell having more than N pixels, comprising:
- respectively associating a plurality of N-pixel decompressed cells of a decompressed bit-map with the plurality of N-pixel compression cells, each decompressed cell having a decompression fill order pattern of fill order values that are based on half-tone threshold values of the corresponding pixels of the associated compression cell;
- and
- writing data in the decompressed bit-map in accordance with the pixel counts and the decompression cell fill order pattern.
A printing apparatus comprising:
- a memory for storing a compressed half-toned bit-map;
- a processor for decompressing the compressed half-toned bit-map into a decompressed bit-map that includes a plurality of N-pixel decompressed cells, wherein each decompressed cell has an associated fill-order pattern that is based on half-tone threshold values for a corresponding N-pixel compression cell of an uncompressed half-toned bit-map on which the compressed half-toned bit map is based, wherein the half-toned bit-map was produced using a half-tone cell having more than N pixels.
Dependencies are inferred from the claim text.