Abstract

A range detecting method and apparatus of a construction, in which first and second images of an object to be formed by a range finding optical system with a relative positional parallax corresponding to the object distance are scanned purely electrically by the use of one or more photo-sensor arrays, then analog image element signals concerning these first and second images obtained at this time are sequentially converted into two-value signals, after which the two-value signals are stored, as inputs, in first and second digital storing device where the coincidence and non-coincidence of these digital image scanning signals stored in these first and second storing devices are detected by means of a coincidence detecting device, while one of these image scanning signals are relatively shifted bit by bit with respect to other image scanning signals, and the shift bit quantities required until the digital image scanning signals of the same bit numbers concerning these first and second images may become optimumly coincided, thereby finding out the object distance from the shift bit quantities.