We use polarization analysis in triangulation-based laser scanners to disambiguate the true laser stripe from spurious inter-reflections caused by holes and concavities on metal surfaces. Stripe candidates are discriminated by projecting linearly polarised laser light and measuring the polarization state of the linearly polarized component of the observed stripe candidates. Initial experimental results are reported and discussed.

We report a novel application of polarization based vision addressing the robustness of laser triangulation range sensors. Such sensors are based on the accurate detection of a pattern of laser light projected onto a scene, usually a point or line. Typical problems arise with highly specularly reflective surfaces, which can generate visible reflections of the light in various parts of the image. This can confuse the detection algorithms and lead to wrong range measurements. This paper demonstrates experimentally the feasibility of polarization based vision for disambiguating multiple specular inter reflections of the laser light. We concentrate on metal components as they have high interest for inspection in manufacturing, and show positive results with situations of various complexities.>