High Precision Dent Detection by Photometric Stereo Using High Dynamic Range Camera

Abstract

This paper describes a method for an automatic detection method of the small dent on the metal plate. We employed the photometric stereo as three-dimensional measurement method, which has advantages in terms of low cost and short measurement time. In addition, we realized a high precision measurement system by using an 18bit camera. The small dent on the surface of the metal plate is detected by the inner product of the surface normal vectors measured by the photometric stereo. Moreover, we confirmed an effectiveness of our method by detection experiments.