JPS56162570A - Picture signal reading system - Google Patents

Abstract

PURPOSE:To represent halftones of optical information with simple constitution by performing picture processing by the program of a controller by varying the period of the transfer gate timing of a CCD on every scanning line where a picture signal is read. CONSTITUTION:Pieces of picture information by scanning lines read by sensors are applied from CCDs to an amplifier 12, whose output is inputted to automatic background control circuit 13 to set the threshold level of the color of paper such as a document, etc. In reading the picture signal, the period of the transfer gate timing of the CCDs is varied according to every scanning line to hold the threshold level of every scanning line constant. The output of the circuit 13 is applied to a comparing circuit 20, where it is compared with the constant threshold level of every line and converted into a binary signal. Then, it is stored in memories 151-152 and transmitted data by lines is outputted to perform picture processing by the program of a controller, so that while the circuit constitution of the comparing circuit 20 is simplified, halftones of optical information are represented.