INSPECTION METHOD AND APPARATUS FOR PLATE

PROBLEM TO BE SOLVED: To provide an inspection method and apparatus for a plate in which a stain, a scratch, a plating failure, adhesion of a foreign matter and the like caused in the vicinity of a side end on a surface of the plate may be detected.SOLUTION: With a plate W irradiated with illumination light for reflection on a front surface thereof and irradiated with illumination light for backlight on a back surface thereof, an image of an area S including a front surface portion of the plate W and portions outside side ends Wb of the plate W is captured by an imaging part 4. On the basis of the image, the quantity of reflected light 12 reflected on the front surface portion of the plate W and the quantity of backlighting light 11 irradiating the portions outside the side ends Wb of the plate W are measured, and the quantity of the illumination light for reflection and the quantity of the illumination light for backlight are adjusted so that the quantities of the reflected light 12 and the backlighting light 11 may be equivalent to each other and fall in a precedently set range. After adjusting the quantities of the illumination light, an image of the area including the front surface portion of the plate W and the portions outside the side ends Wb of the plate W is captured, and the plate W is inspected for a defect on the basis of the thus captured image.