A flexible calibration method based on a front-coated flat mirror is proposed for a laser light-sectioning three-dimensional(3D)measurement system. Since the calibration target and its mirror image are spatially separ...A flexible calibration method based on a front-coated flat mirror is proposed for a laser light-sectioning three-dimensional(3D)measurement system. Since the calibration target and its mirror image are spatially separated and can be recorded in an image by a camera,the proposed method requires only a single composite image that contains a non-planar checkerboard pattern,a laser strip projected on the target and their mirror images to complete the calibration of the camera and the laser plane in one step. Levenberg-Marquardt(LM)algorithm is used to optimize the system parameters,and the measurement accuracy and speed are improved to enable online 3D inspection. Static and dynamic online 3D measurements are carried out on a cup and a triple stepped shaft,respectively,to validate the proposed method. The shaft has two steps with the depth of(0.5±0.01)mm and(2±0.01)mm to be measured online when the shaft is rotated and translated at the same time. The measurement results can be output at a frequency of 7 to 11 readings per second with standard deviations of 0.040 mm and 0.051 mm. The experimental results verify the effectiveness and flexibility of the proposed method.展开更多
基金supported in part by the National Natural Science Foundation of China (No. 11802132)the Natural Science Foundation of Jiangsu Province(No.BK20180446)。
文摘A flexible calibration method based on a front-coated flat mirror is proposed for a laser light-sectioning three-dimensional(3D)measurement system. Since the calibration target and its mirror image are spatially separated and can be recorded in an image by a camera,the proposed method requires only a single composite image that contains a non-planar checkerboard pattern,a laser strip projected on the target and their mirror images to complete the calibration of the camera and the laser plane in one step. Levenberg-Marquardt(LM)algorithm is used to optimize the system parameters,and the measurement accuracy and speed are improved to enable online 3D inspection. Static and dynamic online 3D measurements are carried out on a cup and a triple stepped shaft,respectively,to validate the proposed method. The shaft has two steps with the depth of(0.5±0.01)mm and(2±0.01)mm to be measured online when the shaft is rotated and translated at the same time. The measurement results can be output at a frequency of 7 to 11 readings per second with standard deviations of 0.040 mm and 0.051 mm. The experimental results verify the effectiveness and flexibility of the proposed method.
