Robust visual servoing: examination of cameras under different illumination conditions

Experience has shown that changes in illumination conditions may influence the robustness of robot control based on machine vision even if such illumination changes appear practically negligible to a human. CMOS cameras have become available with a larger dynamic range than conventional (high quality) CCD cameras. The use of such higher dynamic range cameras for robot control by machine vision is compared with the use of conventional cameras under various illumination conditions. The task to be performed by the robot consists in the removal of a battery from the engine compartment of a used car. In all cases, the servo task could be accomplished successfully. The stop of CCD cameras had to be adjusted manually, however, whereas an automatic adaptation to the current lighting conditions could be implemented for the other camera type, thus allowing us to deal automatically with significant changes of illumination.