Tile based color space transformation
AssigneeXerox Corporation
InventorsXing Li, Peter McCandlish, Clara Cuciurean-Zapan
Life of this patent
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Abstract
A system and method for tile type based color space transformation improves the performance and image quality of multifunction devices. The disclosed embodiments transform an input image on a tile by tile basis. If a tile is detected as neutral, simple 1D L* to CMYK Tone Reproduction Curves or Look-Up-Tables are used to convert the input pixels of the tile in L*a*b* to output pixels in CMYK. If a tile is detected as containing color content, then the input pixels are chrominance adjusted and subsequently converted to CMYK using regular tetrahedral interpolation.
Claims20
A method for tile type based color space transformation, the method comprising:
- with at least one image signal processor, splitting an input image into a plurality of tiles, each tile comprising a plurality of pixels;
- and
- performing a color space transformation, the color space transformation comprising:
- determining the presence of color data within a tile of the plurality of tiles;
- upon a determination that no color data is present within the tile, converting the plurality of pixels of the tile from a device independent color space to a device dependent color space via a one-dimensional look-up table;
- and
- upon a determination that color data is present within a tile, adjusting chrominance of neutral pixels of the plurality of pixels, and converting the plurality of pixels from the device independent color space to the device dependent color space using a method more complex than one-dimensional look up tables.
A multifunction device for tile type based color space transformation comprising:
- at least one image signal processor and a memory in communication therewith, wherein the memory stores instructions which are executed by the at least image signal processor to:
- receive an input image;
- separate the input image into a plurality of tiles, wherein each tile of the plurality of tiles comprises a plurality of pixels;
- determine the presence of color data within a tile of the plurality of tiles;
- upon a determination that no color data is present within the tile, convert the plurality of pixels of the tile from a device independent color space to a device dependent color space via a one-dimensional look-up table;
- and
- upon a determination that color data is present within a tile, perform a chrominance adjustment on neutral pixels of the plurality of pixels and convert the plurality of pixels from the device independent color space to the device dependent color space using a method more complex than one-dimensional look up tables.
A system for tile type based color space transformation comprising:
- at least one image signal processor configured to receive an input image;
- a memory in communication therewith;
- a tile segmentation module in communication with the image signal processor configured to split the input image into a plurality of tiles, each tile comprising a plurality of pixels;
- a color conversion module in communication with the at least one image signal processor configured to convert each tile of the plurality of tiles from a device dependent color space to a device independent color space;
- a color detection module in communication with the at least one image signal processor configured to detect a presence and an absence of color data within each tile of the plurality of tiles;
- a 1D conversion module in communication with the at least one processor wherein upon detection of the absence of color data within a tile of the plurality of tiles, the 1D conversion module converts the tile from the device independent color space to a device dependent color space;
- a chrominance adjustment module in communication with the at least one processor, wherein upon detection of the presence of color data within a tile of the plurality of tiles the adjustment module adjusts the chrominance of each neutral pixel of the plurality of pixels;
- a color transformation module in communication with the at least one processor, wherein upon detection of the presence of color data within a tile of the plurality of tiles the color transformation module converts the tile from the device independent color space to a device dependent color space utilizing tetrahedral interpolation.
Dependencies are inferred from the claim text.