PURPOSE: To perform high-speed processing and accurately reproduce an image. ;CONSTITUTION: The tracing direction of a border point is defined according to whether four picture elements at the periphery of the border point of a picture element are black or white. Namely, the tracing direction is set on a border line where a block picture element is present on the right side and a white picture element is present on the left side; and '1' is set for an upward tracing direction, '2' for a leftward tracing direction, '3' for a downward tracing direction, and '0' for a rightward tracing direction. Further, the respective tracing directions are assigned to the respective bits of a 4-bit tracing direction flag and the bits are set to '1' when there is the tracing direction or to '0' when not. Then all border points of the image are given tracing direction flags and the border points are retrieved according to the tracing direction flag and regarded as origins and while tracing is performed from the origins in the tracing directions, the tracing direction flags at the border points which are already traced are changed; and thus the tracing is carried on all the tracking direction flags show '0000' to find the contour of the image.;COPYRIGHT: (C)1993,JPO&Japio
展开▼
