Abstract: The pages to print need to be converted into halftone image in offset printing procedure. 1}o model the offset printing procedure is the basis of evaluating the duality of halftone image for offset printing. The ideal printer model is assumed in previous researches, i. e. every pixel in halftone image is corresponding to print or blank a small rectangle in the printing media. I}he ideal printer model ignores phenomena of dot gain, missing isolated pixels and clustered dots under a certain limit. This research is to establish a non-ideal printer model for offset printing procedure and incorporate it in halftone images quality assessment algorithm.

Key words: Image quality asscssmcnt,HVS,Printcr modcl,Imagc dilatc,SNR