| 摘要 |
PROBLEM TO BE SOLVED: To precisely detect type and classification of a flaw on a steel plate surface moving at high speed. SOLUTION: The reflected light from the surface of a steel plate 4 is split by beam splitters 7a-7c, and three species of polarized lights which are different from each other are measured with linear array cameras 8a-8c. Beam splitters 7a-7c consist of an optical flat 71 provided with a slit 72 on its surface, for preventing the multiple reflected light from being contained in the reflected light. A signal processing part processes the measured polarization image signal, and calculates amplitude reflectance ratio tanΨbeing an ellipso-parameter of the surface reflected light of an inspected surface, and phase differenceΔ, and reflected light intensity I0 , and, based on the amplitude reflectance ratio tanΨ, the phase difference and the reflected light intensity I0 calculated, type and classification of a flaw on the inspected surface are decided.
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