| 摘要 |
PROBLEM TO BE SOLVED: To make detectable a recessed defect due to a pinhole or the like without being affected by a damage generated by processing or the roughening of a substrate surface by forming a liquid film on a surface to be inspected to pick up the image thereof and processing the obtained image to judge the presence of a defect. SOLUTION: A washing soln. is ejected to a gear while rotating the gear to remove cutting oil or the like and clean air is blown on the gear 1 to drain the washing soln. so that a predetermined amt. of the washing soln. remains on tooth surface. The gear 1 after washing is transferred to an inspection part 3 and the tooth surface is imaged to obtain an original image. Next, a differential image is formed, and succeedingly, a smooth image reduced in noise by smoothing is formed. Thereafter, binarizing processing is performed and a recessed part is detected by the comparison with a predetermined threshold value to judge the result. All of tooth surfaces are inspected in first inspection and, when even one teeth becomes NG, air is blown to perform re-inspection. Only when all teeth become OK in second inspection, the gear is judged to be good and, when even one tooth becomes NG, the gear is judged to be inferior.
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