Single coil digitizer-coupled image scanner

Abstract

A hand-operated optical scanning system which can be used to scan a large document in multiple passes. There is a digitizing tablet containing position-sensing circuitry for outputting a signal indicating the position of a sensing coil in an x-y coordinate system associated with a working surface of the digitizing tablet as well as a buffer memory for receiving pixelized data associated with optical scanning of a document. A hand scanner for scanning the document comprises, a case having a longitudinal axis, guide rollers for allowing movement of the case only substantially along the longitudinal axis, a read bar centered on the longitudinal axis and perpendicular thereto for optically scanning a one-dimensional line of pixels and for outputting a signal reflecting an instantaneous scanned image, and a sensing coil carried by the case centered on the longitudinal axis at a pre-established distance from the read bar for being positionally sensed by the position-sensing circuitry of the digitizing tablet. There is also logic for continuously determining the position and orientation of the read bar, inputting the signal from the read bar, and storing pixelized information into locations of the buffer memory associated with respective locations of the document in the x-y coordinate system.