A new 3D optical triangulation sensor for robotics

This paper describes a new optical range sensor that measures distance and orientation from surfaces. The sensor uses three laser diodes and a position sensitive detector (PSD) camera. The lasers are parallel to each other in a way that their interseption points with the surface define a triangle. The coordinates of each intersection point imaged on the camera can be determined by triangulation. The orientation of the triangular surface patch can be calculated by the cross product of any two sides of the triangle. Experimental results taken with a first prototype show distance accuracy of about 0.05 mm, and orientation accuracy of 0.1 degrees. The prototype can take measures from 60 mm to 750 mm.