The performance of optical measurement systems for 3D imaging of moving targets suffers from motion-induced blur caused by the relative lateral movement between target and measurement system during the finite measurement time (exposure time). This motion blur introduces additional measurement uncertainties, what results in a trade-off between measurement accuracy and acceptable relative velocity of the target. This project aims to eliminate this trade-off by introducing advanced motion compensation and blur correction strategies.
In inline metrology applications, efficient end-of-line quality assurance is achieved by inspecting items on a conveyor belt. However, to attain accurate measurements, the speed of the conveyor belt must be decreased during inspection, which directly results in reduced throughput, becoming a bottleneck in the production line. Motion blur is caused by both process-induced motion (e.g., linear motion of conveyor belt) and disturbance-induced motion (e.g., vibrations). The reduction of the measurement uncertainties requires detailed understanding of these contributors and their effect on the measurement. This enables the development of tailored methods for motion compensation and blur correction. Compensation by means of an optical or opto-mechanical de-scanning strategy together with a suited controller design allows to track the moving target and reduce the relative movement between target and measurement system. Correction allows to further decrease the measurement uncertainties under consideration of additional synchronized measurements, e.g., the residual relative velocity between target and measurement system during the acquisition period. The project investigates various measurement systems for 3D imaging, including triangulation sensors, scanning confocal chromatic sensors, as well as structured light sensor systems.