Image input device for processing a fingerprint prior to identification.

摘要

In an image input device for carrying out preliminary operation prior to identification of an object placed on an input surface, the preliminary operation is for indicating a start time instant of the identification. Responsive to a succession of image signals extracted from the input surface, a timing controller produces partial image signals selected from the image signal succession in correspondence to positions which are unidimensionally or bidimensionally distributed on the input surface. Alternatively, the preliminary operaton is for detecting whether the object is true or false. In this event, grey level comparison may be made as regards selected ones of the image signals that are in correspondence to preselected positions of the input surface. Variation of the image signals may be monitored at two different time instants. A false input can be avoided by changing luminous intensities of the image signals with time or by projecting a specific pattern onto the input surface to detect the specific pattern.