Laser triangulation measurements on moving samples with reduced lateral feature uncertainty

Abstract

This paper proposes a model-based measurement correction approach for laser triangulation measurements on moving samples. A model of the laser intensity distribution on the moving sample and the obtained intensity distribution on the sensor’s detector are used to decrease the motion-induced uncertainty in lateral feature width in a post-processing step. This is achieved by detecting sharp edges, which are often feature-defining elements, with high lateral accuracy. The enhanced feature width accuracy is evaluated using an experimental laser triangulation sensor. Experimental evaluation demonstrates an improvement of 60% in lateral accuracy. Furthermore, the proposed method detects features that are missed in conventional dynamic laser triangulation measurements.