| 摘要 |
PURPOSE:To extract automatically an apex by tracking the contoure of a polygonal closed region drawn on a sketch and calculating the degree of discordance between two windows including prescribed picture elements on the basis of the centers of two tracing points having a fixed distance. CONSTITUTION:The inner side of the contour line of a closed region is successively traced to obtain a tracing point list 11 which stores the coordinates of the tracing centers in the order of tracing. A square region containing (NXN) picture elements formed centering on the tracing point is cut-out from a material video. At the same time, other tracing points having a prescribed distance on the list 11 are obtained to obtain the same (NXN) square region. Then the exclusive OR of each element in both regions is calculated, and the number of ORs of ''1'' is calculated to obtain a discordance degree list 15. Thus an apex is decided at a place where the degree of discordance exceeds a certain threshold value. |
