Color-balanced TRC correction to compensate for illuminant changes in printer characterization
AssigneeXerox Corporation
InventorsThyagarajan Balasubramanian, Shen-Ge Wang
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Abstract
A color marking device includes a color balance controller which adjusts the TRC linearization in accordance with an intended illuminant for viewing the output of the device. The system comprises a front end converter for converting an input signal representative of a target image comprised to preselect the color into a device dependent control system in accordance with the device TRC. The device TRC is selected in accordance with a signal identifying the intended illuminant for the output.
Claims9
A method for selectively characterizing a color marking device relative to a plurality of viewing illuminants for enhanced output image accuracy when illuminated by a predetermined one of the plurality, the method comprising steps of:
- building a device transformation profile for mapping a device independent color description signal to a device dependent color description signal, wherein the profile includes a multi-dimensional look-up table (LUT) and a first set of tone reproduction curves (TRCs), and wherein the first set of TRCs is calibrated for a first selected viewing illuminant comprising a selected light source for illuminated viewing of an output image generated by the color marking device;
- building a second set of TRCs characterized for a second viewing illuminant;
- and,
- responsive to a user instruction for outputting an image intended for illumination by the second viewing illuminant, adjusting the transformation profile to effect transforming an input color representation signal of the image with the LUT and the second set of TRCs.
A system for characterizing a color marking device relative to a selected viewing illuminant for system output, wherein the viewing illuminant comprises an intended light source for illuminated viewing of a system output image generated by the color marking device comprising:
- a profile including a LUT and a first set of TRCs calibrated for accurate color output as viewed under a first viewing illuminant;
- and,
- an adjusted profile including the LUT and a second set of TRCs calibrated for accurate color output as viewed under a second viewing illuminant whereby system characterization for deriving a color correction transformation relative to a plurality of viewing illuminants places reduced demands on system storage for simplified profile management.
Dependencies are inferred from the claim text.