A two-step calibration method of a large FOV binocular stereovision sensor for onsite measurement

•A two-step calibration method of large FOV stereovision for onsite measurement is proposed.•It can comprehensively and accurately calibrate camera-intrinsic parameters.•A novel method of corner detection based on region of interest is proposed.•The Epipolar constraint is introduced into the calibration of structure parameters.•A case study indicates the calibration accuracy of our method is higher than the tradition method’s.

As there are some shortages with using both standard calibration method and self-calibration method to calibrate a large Field of View (FOV) binocular stereovision sensor, a two-step calibration method of a large FOV binocular stereovision sensor for onsite measurement is proposed. Furthermore, in order to improve the calibration efficiency, a novel method of corner detection based on region of interest (ROI) is also proposed to quickly detect the chessboard corner in the image of a small calibration target. Compared with the other two methods, the proposed method is more suitable for rapid onsite structure–parameter calibration of a large FOV binocular stereovision sensor. The experiments show that the onsite calibration process is efficient, and the average value of 10 measurements for a distance of 1071 mm is 1071.03 mm with a RMS less than 0.1 mm. Moreover, the application results indicate that the measurement accuracy of the stereovision prototype system calibrated by this method is improved by 13.56% compared with the other from standard calibration method.