Non-linear resampling for edge-preserving moire suppression

Printing techniques using classical halftoning need to resample the original image on the screen lattice. This resampling can cause undesirable moire artifacts in the screened image. For example, gravure printing is highly susceptible to moire, not only because its low resolution screen lattice but also because the degree of freedom in constructing halftone dots is limited due to the physical constraints of the engraving mechanism. Current resampling techniques compute new samples by simple interpolation methods, i.e., bilinear interpolation which cannot prevent moire very well. Therefore precautions against moire have to be made in the prepress-phase which is not practical and sometimes not feasible. This paper presents a novel technique to adaptively resample an image on the screen lattice using a local estimate of the risk of moire. The purpose is both moire suppression and edge preservation