| 摘要 |
PROBLEM TO BE SOLVED: To surely detect a black defect included in transparent granular tested objects to be tasted. SOLUTION: In an inspection unit 2, a lower illuminating apparatus 4 is arranged below a transparent conveyor belt 3, while a horizontal radiation apparatus 5 is arranged directly beside the conveyor belt 3. An image of a tested object S is photographed by means of an imaging device 6 in the inspection unit 2 so as to be processed by means of an image processor 7, and if a colored part is detected in the tested object S, it is determined as being a defective item. Because illuminating light from the horizontal radiation apparatus 5 illuminates the side face of the tested object S, a shadow, which may be generated in the end part of the object to be tested, when lighting is carried out only by the lower lighting apparatus 4, is not generated. Therefore, the image taken by the imaging device includes no shadow, and wrong determination of a defective part can be prevented.
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