| 摘要 |
PURPOSE:To shorten the time required for extracting contour lines, by extracting contour data in such a way that intermediate data point strings are stored by scanning a memory which stores contour point data one time and a point string buffer is operated by one time so as to connect the intermediate data point strings with each other. CONSTITUTION:Contour point data on a picture are stored in a contour point data memory 3 in the order of raster scan and, when the first contour point data are read out from the memory 3, the Y-coordinate value of a register 11 of terminal point of point string is set at a process decision circuit 12 in the first place. Then the contour point data are sent to a starting point detecting circuit 14 where the starting point of one side data point string is detected and sent to a point string buffer 10. A raster scan terminating signal S is given from the circuit 12 to a closed loop forming circuit 16 and the circuit 16 decides that the terminal point of the data point string is in a connected relation and reads out data of each data point string by scanning the data point strings in forward and backward directions. The read out data are extracted as contour data obtained when the outline of an object is traced in counterclockwise direction. The data are stored in a contour data memory 4. |
