Patent ID: 6181834
Filing Date: 2001-01-30
Classification: G06T,H04N

Abstract:
A method of downsampling an input digital image defined by plural image pixel gray values arranged in n rows extending in a fast scan direction and m columns extending in a slow scan direction to a reduced-size output image defined by plural image pixel gray values arranged in k rows and l columns, wherein k<n and 1.ltoreq.m or k.ltoreq.n and 1.ltoreq.m, said method comprising:determining a plurality of averaging areas in said input image, each averaging area corresponding to an image pixel gray value location in said output image and defined by dimensions efs in the fast scan direction and ess in the slow scan direction, wherein efs and ess are determined according toefs=fsfactor/fsscaleess=ssfactor/ssscaleand wherein fsscale and ssscale are scaling factors for the input image in the fast scan and slow scan directions, respectively, fsfactor and ssfactor selected independently of each other according to:fsfactor>0ssfactor>0and so that at least one of fsfactor and ssfactor.noteq.1;for each of said plurality of averaging areas of said input image, obtaining an average of the input image pixel gray values at least partially encompassed thereby; and,for each of said plurality of averaging areas of the input image, assigning the correspondingly located image pixel gray value location in the output image the average of the input image pixel gray values in the averaging area.