Multi-view surface inspection using a rotating table

In this paper, we introduce a method to visually inspect in- dustrial parts by using multi-view images of an industrial part on a rotating table. During the visual inspection of the parts' sur- faces, the relationship between the camera pose, the light vectors, and the normal vectors of a part's surface is the key factor in de- tecting abnormalities. We can change the relationship between the three factors by rotating the part; then, the abnormalities are visible in certain positional relationships. We, therefore, track the points on a part's surfaces in an image sequence and discrimi- nate abnormal points (such as points on scratches or dents) from normal points based on pixel value transitions while rotating the part. The experimental results, which were based on real data of industrial parts, showed that the proposed method could detect the abnormalities on the surfaces.