Pattern rotary angle - revealing systems

摘要

PURPOSE:To exactly detect an angle with regard to a circular pattern as well, by determining the center of gravity of a pattern to be detected, generating a search circle of a prescribed radius centering around said center of gravity, finding each circular are segment and detecting the angle. CONSTITUTION:A CPU 10 derives the center of gravity of an object pattern 1 by a primary moment from a moment extracting circuit 9 and an area from an area extracting circuit 8. Subsequently, a memory 12 is brought to an access so as to draw a circle of a prescribed radius centering around the center of gravity, and plural circular arc segments and its attribute, and a reference segment are extracted. Next, with regard to each attribute of the reference circular arc segment and both its adjacent circular arc segments, a coordination processing of an object sample and a standard sample is executed. After confirming that a corresponding relation of both of them is formed, a rotational angle is detected from an angle made with a prescribed axis of a rotational angle reference point which is defined by a relative position relation to the reference circular arc segment.