| 摘要 |
PROBLEM TO BE SOLVED: To surely detect short and extremely thin surface flaws. SOLUTION: This surface inspecting device is equipped with a polarized light source 10 for linearly irradiating a steel sheet 100 with polarizing light 51 in a lateral direction, a light-detecting optical system 20 for detecting the reflected light 52 from the steel sheet 100 and the signal processing part 30 connected to the line sensor camera 21 of the light-detecting optical system 20. The polarizing angles, incident anglesθi, reflection anglesθr and the like of the polarizing plate 15 of the polarized light source 10 and the light-detecting polarizing plate 22 of the light-detecting optical system 20 are set so that the S/N ratio of a flaw signal to a background noise signal of a normal part becomes maximum, while deciding data 56, wherein a flaw signal is enhanced in a flaw signal-enhancing signal processing part 31 by the integration of a plurality of one-line brightness distribution data 53 and the substraction of a moving average or the like, is calculated in the signal-processing part 30, and feature quantity data 57 is calculated in a feature quantity operational processing part 32, while the inspection data 58 is outputted as a final decision result in a flaw decision processing part 33. COPYRIGHT: (C)2005,JPO&NCIPI
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