Patent ID: 6021950
Filing Date: 2000-02-08
Classification: G06K

Abstract:
A device for checking patterns (1) disposed on a material strip (30), which patterns (1) consist of groups of dark and light areas (2, 2*; 3, 3*), said areas succeeding in a direction (v) of checking, wherein a position of the dark areas (2) and light areas (2*) of one group with respect to a related detector (9) is displaced in regard to the dark areas (3) and light areas (3*) of another group with respect to another related detector (8), which detectors (8, 9) detect an existence of dark areas (2, 3) and light areas (2*, 3*) and produce output signals dependent on a result of the detection, wherein a comparator (10) compares a sequence of output signals with a predetermined sequence of signals, wherein:a) said comparator (10) is directly connected to at least two detectors (8, 9);b) dark areas (2, 3) and/or light areas (2*, 3*) representing output signals are supplied from at least two detectors (8, 9) to said comparator (10);c) said dark areas (2, 3) and/or light areas (2*, 3*) representing output signals of said at least two detectors (8, 9) are firstly combined within said comparator to form a sequence of output signals, andd) said comparator (10) subsequently compares said combined sequence of output signals with a predetermined sequence of signals and creates an output signal of the comparator (10) if both sequences are similar.