Document mosaicing

Document scanning with an over-the-desk video camera offers an attractive a lternative to the flat-bed scanner, photocopier or fax machine, since the d ocuments need not be moved from their usual place of reading. However, stan dard CCD cameras can sample full A4 pages at only 50 dots per inch, which i s not sufficient for anything more than the crudest reproduction. This moti vates the use of "mosaicing", whereby multiple, overlapping images of the d ocument are stitched together seamlessly to form a high resolution composit e. Here we present a novel mosaicing, system optimized for use with documen ts. The user simply slides the paper under the camera: all subsequent proce ssing is fully automatic. The quality of the resulting images is sufficient for OCR or printing, though some post-processing is necessary. (C) 1999 Pu blished by Elsevier Science B.V. All rights reserved.