Patent ID: 7417772

Claim:
A vector error diffusion (VED) method employable in cycles with respect to a bi-tonal color printing engine which prints bi-tonal color images in a device output color space, said method, with respect to each cycle, comprising acquiring input color-image data which is characterized with an input color space, processing, with available pre-established VED accumulated error data, such input data to produce a VED-processed input color-image data stream, from such VED-processed input color-image data stream, and utilizing a color-value data/palette containing color values based upon device output-color-space-determined values for the primary and secondary colors which the printing engine is capable of printing, creating, without employing interpolation, a VED-processed output color-image data stream which is characterized by the mentioned device output color space, and which is suitable for delivery to and use by the mentioned printing engine, said creating including employing, in the mentioned color-value data/palette, additional, fictional color values based upon device output-color-space-selected values for arbitrary C′, M′ and Y′ colors which lie at vector distances that are intermediate the primary C, M and Y colors and white, and changing, as appropriate for the next cycle, the VED accumulated error data which will be employed in that next cycle as pre-established VED accumulated error data.