Patent ID: 6493469
Filing Date: 2002-12-10
Classification: H04N

Abstract:
A document scanning apparatus, comprising:an image acquisition system for simultaneously recording parts of a hardcopy document positioned face-up on a surface; the parts of the hardcopy document being recorded without perspective distortion in a first image and a second image by said image acquisition system; a portion of each of the parts of the hardcopy document recorded in the first image and the second image recording an identical segment of the hardcopy document; and a frame merger module for forming a composite image of the hardcopy document by stitching the first image and the second image together at the portions in each image that record the identical segment of the hardcopy document; said frame merger module identifying the portion in the first image and the portion in the second image by computing correlation values of high gradient images of the first image and the second image for different regions of overlap between the first image and the second image.