公开(公告)号：FR2356328A1

公开(公告)日：1978-01-20

申请号：FR7619832

申请日：1976-06-24

Applicant: IBM FRANCE

Inventor： BEAUDOUIN P ,  DEBORD P

IPC: A61B6/03 ,  H04N1/401 ,  H04N5/217 ,  H04N3/14 ,  H04N1/04

Abstract: A noise reduction scheme for a photosensitive self scan system includes an array of photosensitive elements producing video signals and first and second pluralities of switching elements, one element of each of the pluralities of switching elements being connected to one photosensitive element of the array. A first video line connects each element of the first plurality of switching elements to a first input terminal of a summing device such as a differential amplifier and a second video line connects each element of the second plurality of switching elements to a second input terminal of the differential amplifier. Shift register means operated by clock pulses is provided to control the operation of each of the elements of the first plurality of switching elements to sequentially couple the photosensitive elements to the first input terminal and to apply periodically only clock pulse noise signals through the gate drain capacitance of the second plurality of switching elements to the second input terminal of the differential amplifier, so as to produce at the output of the amplifier a video signal substantially free of noise signals created by the clock pulses.