To detect defects of the surface shape and a luminance defect of an object to be detected, using a simple constitution.
When the image of the surface of the object to be detected 7 is input with a moire optical system having an illumination system 2, a grid 3 and an image input device 4, the phase of the moire fringe to be inputted to the image input device 4 from the moire optical system is shifted by "0", "π/2", or "π" by a phase shift means 5. An intensity distribution calculating means 10 of a processing unit 6 calculates the intensity distribution of the image of a plurality of moire fringes, whose phase are shifted. A form calculating means 11 calculates form data indicating the surface form of the object to be detected 7, from the calculated intensity distribution. A brightness calculation means 12 calculates the luminance data, showing the brightness of the surface of the object to be detected 7, from the calculated intensity distribution. A defect deciding means 13 decides the quality of the shape and the luminance of the object to be detected 7, by comparing the calculated shape data and luminance data with preset reference data.
SAKIDA RYUJI
KAMATA TERUMI
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