Accurately extracting full resolution centers of structured light stripe

Extracting the center of a stripe is one of the key techniques of a structured light measurement system.An approach to increase the extracting resolution for the centers of a laser stripe and the extracting precision is investigated.Firstly,full resolution initial centers of the light stripe is presented based a threshold algorithm.Then,the gray grades of the field along the initial points of the stripe are calculated with a Sobel operator,and the normal direction at the initial points of the stripe is calculated by the Bazen method.Finally,the energy centers of the stripe are accurately gained in the normal direction.A contrast experiment in the V-shaped test block with a camera in resolution of 768×576 indicates that the resolution of the centers is 1086 dots without redundance,and the number of effective dots has increased by 42.5% as compared with that of barycenter method.In addition,the average distance between the extracting corners and the line fitted by the extracting centers is the shortest one,only 0.294 and 0.306 pixel.The proposed method can calculate exactly the normal direction of the stripe,and computing time is 75.8 ms.Experiments show that the approach can avoid a mini density for a large curvature surface of the measured object and can get full resolution centers,it is suitable for online accurate measurements.