Generating multi-bit halftone dither patterns with distinct foreground and background gray scale levels

Abstract

A multi-bit halftone generating system provides for halftone intergeneration in printers which can print dots of plural gray scale levels. Input image data includes information for more gray scale levels than can be handled by those associated with a printing device. Higher order bits of the pixels of the electronic document are used to select a gray scale level from those available from the printer. Remaining bits are used to generate a halftone pattern which is superimposed upon this selected gray scale. Thus, improved dither rendering is quickly and efficiently accomplished and improved image generation results from using the gray scales available from the printing device.