Inertial measurement unit aided extrinsic parameters calibration for stereo vision systems

•The use of inertial measurement units (IMU) offers a feasible solution to directly determine the rotation matrix of the stereo vision system.•An angular differential method has been developed to accurately determine the relative Euler angles between fused camera-IMU units.•The translation vector between cameras is determined from solving a series of linear equations instead of the use of SVD method.•Experimental results suggest the proposed method is comparable to the Zhang's calibration method, and is able to be applied to measurement with large FOV. Calibration of a stereo vision system is essential for three-dimensional shape and deformation measurements. Although the target-based calibration technique is a good solution, it comes with limitations in a large field of view (FOV) measurement due to the target size and difficulties in operation. In this paper, a method using the inertial measurement unit (IMU) has been proposed to calibrate stereo vision systems for large-scale measurements. The prerequisite for this method is to calibrate the camera intrinsic parameters in advance. With the alignment of IMU sensor with the camera, the relative rotation between the two cameras can be determined through coordinate transform. An angular differential method has been developed to improve accuracy in determining the yaw angle. After the epipolar geometry is constructed upon stereo scene correspondences, the translation vector can be obtained by solving a set of linear equations, since the intrinsic parameters and the relative rotation are predefined. The proposed method does not require any known calibration target, leading to easy operation in practice. Two laboratory experiments are presented to demonstrate the use of the method. The experimental results show that the accuracy of the proposed method is comparable to that resulted from the well-known Zhang's method, and it can also be applied to measurement with a large FOV.