US Patent 7319549 Multiple weight error diffusion

A method for halftoning includes the steps of defining a first set of weight sets, and defining a second set of weight sets. A first error associated with a first pixel location of a plurality of pixel locations is diffused to a first neighboring at least one pixel location using a first weight set selected from the first set of weight sets, and a second error associated with a second pixel location of said plurality of pixel locations is diffused to a second neighboring at least one pixel location using a second weight set selected from the second set of weight sets. The first diffusing step and the second diffusing step are alternately performed along each scanline in the image to reduce visual artifacts.