Development of Technology to Inspect Dents on Metal Parts Adhered with Machining Oil

Automated visual inspection of dents on metal parts immediately after press working presents two primary challenges. The first challenge is the varying inclination of the measured surface from part to part, which can be a significant obstacle. The second challenge is the uneven distribution of machining oil on the surface, which further complicates the inspection process. To address these issues, a method has been proposed to expand the measurement range of surface inclination and reduce the impact of machining oil adhesion. This method involves capturing a series of images with varying illumination angles. The challenges were addressed by normalizing the acquired series of images in the direction of the illumination angle and then integrating them. The effectiveness of this method was confirmed through experiments.