Abstract: Aiming at the scene that GNSS RTK can not provide coordinates due to signal occlusion or difficult station erection during pipeline measurement, this paper proposes a monocular vision coordinate transfer method with IMU aiding. Firstly,the camera is set up at two known RTK points to capture imagesand the IMU data is collected simultaneously. Then extracting and matching image features, restoring relative rotation, transition and scale. Finally triangulating the point to be measured, the coordinate of the point in the camera coordinate system of the real scale can be obtained. Referring to the initial alignment method of the IMU static base, projection of gravity vector and the optical center vector between the cameras in the geographic coordinate system and the camera coordinate system can be used to solve the rotation matrix between the two coordinate systems, and further obtain the the three-dimensional coordinates of the point to be measured in the geographic coordinate system. Compared with other measurement methods, the method is flexible and convenient, the device is light, and the operation is simple. And we can obtain any coordinate in the camera field of view with a single measurement.The experimental results show that the error average of the horizontal coordinate is 0.12 m, and the error average of the elevation is 0.2 m.

Key words: pipeline measurement, RTK, IMU, monocular vision, coordinate transfer