PURPOSE: To process a loop pattern having no cross points, by erasing segment patterns other than loop patterns and extracting artificial end points of loop patterns to trace them.
CONSTITUTION: A pattern extracting part 41 converts linear patterns to labels in lattice units. An end point code extracting circuit 42 extracts end point codes like end codes. An end point extracting circuit 43 extracts end points of segments having no end point codes and sends them to an integrating circuit 44. In respect to picture data set in a table memory 45, patterns other than loop patterns having no cross points are erased by a cross point extracting circuit 46 and an end point tracing processing circuit 47. When a loop pattern having no cross points is left, the start point is obtained by an artificial end point extracting circuit 48, and the pattern is traced in a tracing processing circuit 49 49 by the known method.
OSADA SHIGEMI
MATSUURA TOSHIO
