Immediate verification of printed copy

摘要

Print verification is done by scanning the printed copies, thereby forming a stream of scanned images of the specific pages. Digitized images from the stream are then spatially aligned page by page, line by line and pixel (pel) by pixel (pel) with corresponding digitized images in a stream of source images. The source and scanned images are compared to find pel sequences that are different. These differences represent defects in the printed copies.