Facsimile and static presentation processing – Natural color facsimile – Specific image-processing circuitry
Reexamination Certificate
2002-03-29
2004-06-22
Grant, II, Jerome (Department: 2626)
Facsimile and static presentation processing
Natural color facsimile
Specific image-processing circuitry
C358S518000, C358S523000, C358S525000
Reexamination Certificate
active
06753988
ABSTRACT:
BACKGROUND
The present invention relates to color data conversion and more particularly to devices and methods for converting color data from a color space to a print space.
Certain image processing devices, such as printers, displays, image rendering systems and output files may use a different color space than other image processing devices such as a color driver for a computer system, camera, display or input graphics file. For example, a cyan, magenta, yellow and black (CMYK) color space is used for a color printer. However, a red, green and blue (RGB) color space may be used for certain graphics files. Accordingly, a color transformation is needed for converting the RGB color space into the CMYK color space.
One method of color transformation uses a look-up table to store a plurality of color values associated with the CMYK color space. A conversion between the RGB color space and the CMYK color space is performed by indexing the CMYK values in the look-up tables using addresses corresponding with RGB color values, one look-up table per output color.
A large amount of memory is required for the look-up table. For example, a 24-bit RGB color system may use 8 bits for red color values, 8 bits for green color values and 8 bits for blue color values. This 24-bit RGB color system can require a table size of 16 MegaBytes (MBs) or larger per output color.
To reduce memory requirements, some color transformation devices combine interpolation with the color mapping process. The hybrid transformation process first identifies a set of vertices that surround or neighbor an input color point in the color space. A value for the second color space is then derived by interpolating the identified vertices to the relative position of the input color point. However, this interpolation process is computationally intensive.
SUMMARY
A color data converter includes a plurality of memories configured to store lattice points for a color space. The lattice points of the first axis are assigned to memories in a sequential manner. The lattice points along the other two axes are assigned to memories in an alternating manner.
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Cypress Semiconductor Corp.
Grant II Jerome
Marger Johnson & McCollom PC
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