Abstract: The problem associated with calibrating a structured-light-stripe vision sensor is that known world points on the calibration target do not normally fall onto the light stripe plane illuminated from the projector. To address this problem, a method basing on the invariance of double cross ratio is proposed for calibrating structured-light-stripe vision sensor, and the calibration target is designed. By this method, arbitrary amount of 3D world calibration points on the structured light plane can be easily obtained, thus the problem that it is difficult to obtain adequate 3D world calibration points is settled and the calibration accuracy of structured-light-stripe vision sensor is definitely improved. The experiments conducted suggest that the proposed calibration method is of high accuracy and is applicable to many structured light based 3D visual inspection tasks about large workpieces.

Key words: Calibration, Invariance of double cross ratio, Structured-light-stripe vision sensor, Visual inspection