Patent ID: 6538772
Filing Date: 2003-03-25
Classification: H04N

Abstract:
A conversion method for generating a half-tone image from a digitized image comprising a set of pixels each having a tone value, with each pixel of the digitized image being associated with a base cell of the half-tone image, said base cell being subdivided into as many unit zones as there are non-zero tone values, the method comprising:analyzing the digitized image in terms of analysis windows each constituted by grouping together a predetermined number of pixels; and at least when the tone value of at least one of the pixels in an analysis window falls within a first predetermined set of tone values, converting the tone value of each of the pixels of the analysis window into respective selected ratios of inked area to non-inked area in various base cells corresponding respectively to said pixels, said base cells together forming a supercell, said conversion being performed by complying with a predetermined distribution and filling order of unit zones that is a function of the tone value to be converted, said distribution and said filling order also taking account of a printing technique used for reproducing the half-tone image on a medium, a resulting image having two zones with different screen pitches without any sharp transition therebetween.