| 摘要 |
PURPOSE:To automatically detect the position of a screen without requiring a trial printing by arranging a positioning mark including a curve in its outline at a plurality of points on said screen and detecting the shape of said positioning mark through meshes from a specific position. CONSTITUTION:After a pattern is detected 40, it is binarized 41 and turned into a two-dimensional binary-coded digital image, the outermost outline of the pattern is detected. Then, a middle point of a convex hull is obtained from a group of points defining the outermost outline, and a Voronoi figure of the farthest points which are vertexes of the convex hull is formed. Thus, a circle having the shortest radius among those crossing three points corresponding to the three Voronoi area adjacent to the Voronoi point centering the Voronoi point, i.e., the minimum inclusive circle is obtained. The center of this circle is made the position of a positioning mark. Since the outermost outline is detected through simple processing of the image, the amount of input data for detection of the convex hull which necessitates more complicated processing can be reduced, resulting in the reduction of the entire processing time. |
