Polarization-based peak detection in laser triangulation-range sensors

We report a polarization-based peak detection method for use in laser triangulation range sensors. Such sensors depend critically on the accurate detection of a pattern of laser light projected onto a scene, usually a point or line. Problems arise with highly specularly reflective surfaces, which can generate visible reflections of the light in various parts of the image. These can confuse intensity-based detection algorithms and lead to incorrect range measurements. This paper demonstrates the failure of intensity-based methods by reference to an existing triangulation scanner and sample depth data. A polarization-based method is proposed and we demonstrate experimentally the feasibility of polarization-based vision for disambiguating multiple specular inter-reflections of the laser light.