Windshield shape inspection using structured light patterns from two diffuse planar light sources

The objective of this paper is to propose a wind- shield surface shape and optical parameters inspection system. In this paper, a white board works as a diffuse planar light source projecting structured light patterns because physical properties of specular surface do not allow us to directly apply the triangulation-based techniques used in ordinary diffuse surface inspection. The board is placed at two different positions and the distorted structured light patterns are observed by a fixed camera so that the incident vector for every point on the windshield surface is determined using corresponding points in the board at two different positions. Likewise, the reflection vector is determined by camera calibration. Hence, the 3D shape and normal of the windshield surface are obtained by the intersection of the incident and reflection vectors. The normal of the surface denotes the optical reflective property of the windshield. Last, accuracy and consistence experiments are conducted. The experiment results demonstrate the efficiency and accuracy of our system.