| 摘要 |
PURPOSE:To detect accurately a linear flaw in a photoscanning direction by storing a scanning signal of every scan and comparing it with the signal of the last cycle for decision making, and deciding on the distribution of decision signal in the flow direction of a body to be inspected. CONSTITUTION:The output of an arithmetic circuit 24 is compared by a comparative decision circuit 25 with a set value from a setting circuit 26 synchronously with the body 13 to be inspected. This comparative decision result is tracked by a tracking circuit 27 in the movement direction and stored. The output of the tracking circuit 27 is supplied to discrimination circuit 28, which discriminate on the kind of a flaw on the basis of the distribution of comparative decision results stored in the circuit 27 in the movement direction of the body 13 to be inspected. Namely, when, for example, >=3 continuous decision results which are stored indicate the presence of flaws, the decision on a surface flaw 4 is made, and when <=2 results indicate the presence of flaws, a discrimination on flaws 3 and 3' in the scanning direction of a laser beam 1 is made. |
