Image signal processing with a variable threshold

摘要

An image signal processing apparatus particularly suitable for use in a facsimile system for converting an analog image signal obtained by photoelectrically reading an original into a binary image signal for further processing is provided. The present image signal processing apparatus comprises a digital-to-analog converter and a digital data input unit, preferably a microcomputer, connected to the converter. Thus, the level of the reference voltage to be supplied to the comparator for converting the analog image signal into the binary image signal may be finely adjusted appropriately without complication in structure.