| 摘要 |
PURPOSE:To execute proper validity/invalidity decision also for a pattern having any area and any shape by using a threshold proportional to the peripheral length of a reference pattern at the time of deciding validity/invalidity. CONSTITUTION:A peripheral length value obtained by a peripheral length measuring circuit 8 is sent to a threshold forming circuit 9 and the circuit 9 forms a threshold proportional to the peripheral length on the basis of the sent peripheral length. The threshold is used as a threshold at the time of deciding validity/ invalidity by a correlation circuit 6. Since the peripheral length of the reference pattern is measured and a value proportional to the peripheral length is fixed as the threshold, a proper threshold corresponding to the area of the pattern and the complexity of the shape can be obtained. Even if the pattern is a small, large, simple, or complex pattern, the validity/invalidity can be extremely properly decided. |
