Calibration of an industrial vision system using an ellipsoid

A robust multi-camera calibration algorithm developed for an industrial vision system is described. An ellipsoid with a simple surface pattern and accurately known geometry is used as a calibration target. Our algorithm automatically detects the presence of the ball on the conveyor and accurately determines the position of its outline and marker lines in each image frame using efficient image processing techniques. A fast least-squares minimization is then performed to determine the optimal camera and motion parameters. The method is fully automatic and requires no human interaction or guidance, helping to minimize machine setup and maintenance times. The calibration algorithm has been demonstrated on real image captures and performance is quantified using simulated image sequences.