| 摘要 |
PURPOSE:To detect the existence and the position of a block of a closed loop consisting of vertical and horizontal segments and segments inclined at 45 deg. in automatic drawing reading, by discriminating whether the detected closed loop is the block or not. CONSTITUTION:By a closed loop detecting circuit 102, all bits of a link storage part 106 whose bits correspond to bits of a picture storage part 107 in 1:1 are reset to ''0'', and bits of the link storage part 106 corresponding to the outermost line of a drawing 201 are set to ''1'', and bits set to ''1'' on the picture storage part 107 are regarded as obstacles, and bits set to ''1'' on the link storage part 106 are propagated near 4. For the purpose of discriminating whether each detected closed loop is a block or not, the closed loop formed by bits set to ''1'' in the picture storage part 107 is traced by a tracing circuit 104. The operation of the tracing circuit 104 is monitored by a trace end point discriminating circuit 105; and when the tracing reaches the same coordinates as the start point, the circuit 105 discriminates that the tracing of one closed loop is terminated. |
