Tone modifying dithering system

Abstract

A method for correcting the tone of an input image for display on a given output device includes the steps of generating a dither template having advantageously more threshold levels than color levels of the input image. A tone characteristic for the output device is determined by comparing actual output pixel values against expected image pixel values. The tone characteristic curve is scaled to correspond with the number of threshold values in the dither template, and is stored in a look-up table having a number of entries corresponding to the number of threshold values in the dither template. The dither template values are fed to the look-up table, which provides an adjusted dither template which reflects the tone correction required to provide an output image free of tone distortion. The adjusted dither template is then normalized in accordance with characteristics of the input and output display devices. Elements of the normalized dither template are compared against incoming image pixels to determine which input image pixels are to be displayed on the output device.

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