Optical triangulation: A dual-channel configuration

Scattering of light from a rough surface is modeled and the power of the scattered light received by the collecting lens in optical triangulation measurements is calculated. This light power signal is used to improve displacement measurements and to identify the surface slope or inclination of a sample in the optical triangulation method. In this way, the improved optical triangulation method described here is able to measure smooth samples that are difficult to be measured by conventional optical triangulation techniques. The inaccuracy of the sensor is better than 0.5%. (C) 1996 American Institute of Physics.