| 摘要 |
In a computer system (10) that employs an ink-jet printer (12), a printer driver (36) receives signals from an applications program (34) that describes an image in multiple-bit pixel values. The driver converts the multiple-bit-per-pixel representation into the binary-pixel-value format necessary to operate the printer. In so doing, it submits the image values I(x,y) to complementary weighting processes (136 and 138). It then applies clustered-dot dithering to one of the weighting-process outputs and distributed-dot dithering to the other weighting-process output, and it commands the printer to apply ink at any pixel for which the output of either dithering step calls for it. Except at the highest pixel values, the weighting is such that the overall output is the same as that which clustered-dot dithering produces. At the highest pixel values, the results tend increasingly toward those of dispersed-dot dithering as the input value in-creases. The result is the avoidance of the white flecks that would otherwise afflict the darkest areas, particularly when printing is performed on media that require ink-duty-cycle limiting.
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