Hewlett-packard Company

Christopher T Creel

Marcus A Smith

Dana A Jacobsen

Jason Main

A multi-staged image processing pipeline in a page printer includes a splitter stage for splitting a scan line of print data into sections for improved formatting efficiency and speed in the pipeline. In a preferred embodiment, the splitter stage forces a section of the scan line data to be processed by all relevant image processing stages with reduced cache thrashing. Each section of scan line data is set to be of a size that is optimal for (i.e., not greater than) the cache memory available. Advantageously, the splitter provides dynamically configurable splitter sizing and enables each stage to work on the data that is currently in the cache.

Scan line splitting in a multi-staged image processing pipeline

A method and apparatus enables derivation of a bitmap representation of an image, where the image includes a region filled with a pattern. The method includes the steps of: accessing an original pattern bitmap segment from within the image; translating a copy of the original pattern bitmap segment to the origin of the bitmap representation of the image as a reference pattern bitmap and arranging it as a reference pattern bitmap with a pattern that evidences a consistent phase regularity with the original pattern bitmap segment; filling the region to be filled with the pattern by determining a correspondence of an anchor pixel of the region to a pixel in the reference pattern bitmap; ascribing an attribute of the corresponding pixel in the reference pattern bitmap to the anchor pixel of the region; and repetitively determining correspondence of each further pixel in the region to a further pixel in the reference pattern bitmap and ascribing an attribute of each further pixel of the reference pattern bitmap to each further pixel in the region, until all pixels in the region have been processed.

Printer with procedure for pattern tiling and scaling

A print data processing pipeline for use in a color electrophotographic printer optimizes print quality and minimizes memory usage by separately processing lossy and lossless print data. Lossy print data may include print data for images and lossless print data may include print data for text, line art, and graphics. Partitioning print data into lossy and lossless elements allows application of the print data compression operations optimized for each type of print data. High compression ratios can be achieved on lossy print data by applying visually lossless compression operations designed for the lossy print data. In addition, high compression ratios can be achieved on the lossless print data by applying lossless compression operations designed for the lossless print data. A merge unit combines the lossy and lossless print data streams after decompression to reconstruct the original image using merge data. The merge data is generated in an image processing operation which accounts for the different transparency modes of the page description language print data so that the correct foreground and background placement of objects is maintained. Placement of the color space conversion operation and the halftone operation relative to the merge operation, further optimizes the print quality while minimizing memory usage. The print data processing pipeline includes a direct memory access controller which has the capability to allow print data to be selectively directed to the lossy or lossless compressor/decompressor, the color space converter, or the merge unit.

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Boise, ID, United States of America

Christopher T Creel