A close-up photogrammetry method with additional distance and angle observations for particle accelerators measurement and simulation experiments

Abstract Laser trackers or total stations are most widely used in particle accelerator measurement with high measurement accuracy but low efficiency. Close range photogrammetry has great characteristics of both high accuracy and efficiency, other than that, it enables non-contact observation, which is ideal for high-radiation accelerator measurement environments. In order to obtain the absolute position of the measurement area using close range photogrammetry, the position and orientation of the camera and the scale of the photo must be accurately determined at the moment of observation. A new three-dimensional visual measurement equipment is developed in this paper, which can obtain image, distance, and angle data at the same time. Unified adjustment of all three types of observations can more accurately determine position, orientation and scale datum. We used simulated data for experimental validation, comparing the new algorithm with another two algorithms: the traditional fixed point constraint and centroid datum constraint. The experiment results show that it can significantly improve positioning accuracy by adding distance and angle observations. The three-dimensional coordinate accuracy can reach up to 0.073 mm, while the accuracy of the other two algorithms can only be achieved 0.137 and 0.153 mm, the improvement is approximately 52.4%. Especially in the forward direction of the tunnel, the positioning accuracy is significantly improved, with an improvement of about 67.8 %.