Dynamic deflectometry: A novel approach for the on-line reconstruction of specular freeform surfaces

Abstract

The dynamic inspection and reverse engineering of specular freeform surfaces is a challenge so far largely unsolved. Products produced in high quantities in industrial environments are still inspected manually which is labour intensive, expensive, monotonous and subjective. We propose a novel deflectometric hardware setup and methodology to overcome this shortfall. The reflection of a line laser from a moving specular surface is captured on a translucent screen. The resulting complex line provides detailed data about the surface gradients at the intersection of the laser light plane and the surface but cannot create correspondence between points of reflections and surface points. The latter is inherent in a traditional active light scanning setup whose data alone will, for specular surfaces, be subject to high levels of noise. We propose a novel method that by simulation of the reflection fuses the two data sets to allow digitalising moving specular surfaces with the high slope sensitivity of deflectometric methods.