| 摘要 |
PURPOSE:To reduce the calculation time of flaw area by determining a frequency distribution in scanning of a laser beam over the surface of a test object with respect to the count of the normal surface obtained from each scanning based on detection signals of the reflected beam. CONSTITUTION:A laser beam scans over the surface of a test object and reflected beam signals 9 are converted into normal surface discrimination signal 14 via a nomal surface discrinimation circuit 19. This signal is imputted into an AND gate 18 with a inspection area signal 16 and a clock pulse 17 and applied to a counting circuit 20 as normal surfac pulse 19. A normal surface counted value 21 is inputted into a CPU23 with a counting end signal 22 to determine a frequency distribution through a memory device 25. Based on the result, a flaw area D is calculated by computing D=ASIGMA(K=1,h)K [NL-K], where NL is proper length of the test object, K natural number, and h natural number of maximum value NL. This can reduce the calculation time of the flaw area. |
