Patent ID: 7898692
Filing Date: 2011-03-01
Classification: H04N

Abstract:
1. An image forming method for digitally reproducing a moiré-free color halftone image using a different halftone screen for each of five colors, the method comprising: using a color halftone screening apparatus to perform: defining a first color halftone screen having a first fundamental frequency vector V defining a second color halftone screen having a first fundamental frequency vector V defining a third color halftone screen having a first fundamental frequency vector V selecting the values of the fundamental frequency vectors to identify combinations that do not produce objectionable moiré by satisfying the following thresholds: where V defining a fourth color halftone screen having a first fundamental frequency vector V defining a fifth color halftone screen having a first fundamental frequency vector V selecting the values of the fundamental frequency vectors for the fourth screen and fifth screen to satisfy so that the set of five different halftone screens used in combination, in an image forming apparatus, produce moiré-free halftone output.