Description and Evaluation of a Simplified Model to Simulate the Optical Behavior of an Angle-Resolved Scattered Light Sensor

Abstract

Scattered light sensors are optical sensors commonly used in industrial applications. They are particularly well suited to characterizing surface roughness. In contrast to most geometric measuring devices, a scattered light sensor measures reflection angles of surfaces according to the principle of the so-called mirror facet model. Surfaces can be evaluated based on the statistical distribution of the surface angles, meaning the gradients. To better understand how the sensor behaves, it is helpful to create a virtual model. Ray-tracing methods are just as conceivable as purely mathematical methods based on convolution. The mathematical description is especially interesting because it promotes fundamental comprehension of angle-resolved scattered light measurement technology and requires significantly less computation time than ray-tracing algorithms. Simplified and idealized assumptions are accepted. To reduce the effort required to simulate the sensor, an attempt was made to implement an idealized mathematical model using Matlab® to be able to quickly generate information on scattered light distribution without excessive effort. Studies were conducted to determine the extent to which the results of modeling correspond to the transfer characteristics of a virtual Zemax sensor, on the one hand, and with the measurement results of the actual scattered light sensor, on the other hand.