FLYING APERTURE READING SCHEME WITH FIBER OPTIC DELAY LINES
Original Publication Date: 1980-Aug-31
Included in the Prior Art Database: 2004-Apr-02
Xerox Disclosure Journal
Disclosed is an improvement to a flying aperture reading scheme whereby multiple apertures are utilized in a signal enhancement scheme that circumvents the limitations inherent in a single aperture system in which the speed of operation may be limited by the radiance available from a sheet of paper and the fact that the aperture "dwell time" on reading a point is very short. The scheme involves detecting each spot several times (by using a number of apertures) and adding the outputs with suitable time delays so as to make the various detections of each spot time coincident. By this method the effective signal-to-noise ratio for a given scan rate could be increased due to the coherent signal addition. In order to produce the needed delays, each aperture has behind it an optical fiber, which provides a delay complementary to that introduced by the scanning system, all fibers going to a single detector.