Overall Calibration Method Of Multi-camera Visual Positioning System For Immersive Measurement

Facing the problems of poor interaction between measurement personnel and measuring equipment in the manufacturing process of large-scale equipment such as aerospace and shipbuilding,and low measurement efficiency,a new immersive measurement method that enables measurement personnel to quickly integrate into measurement scenarios and grasp measurement information in real time is proposed.Multi-camera visual positioning systems occupy an important position in immersive measurements.In this paper,the multi-camera positioning system for immersive measurement proposes two multi-camera system calibration methods due to the difficulty of calibration such as no common field of view,complicated method and low precision.One is the calibration of multi-camera system based on three-dimensional stereo control field.The method is to construct a three-dimensional stereo target,and to control the field image through multi-camera multi-position shooting,to establish a global constrained optimization equation group,and to solve the internal and external parameters of the multi-camera system as a whole.Another multi-camera calibration method based on precision two-dimensional angle reference introduces a precision two-axis turntable,which enables the multi-camera system to take multiple shots of the target image multiple times when the turntable drives the multi-camera system through each camera field of view,optimizing the external parameters between the multi-camera system and each camera to the turntable coordinate system to solve the external parameters in the multi-camera system.This paper analyzes and demonstrates the overall design and positioning principle of the multi-camera positioning system,the calibration method and calibration principle of the proposed calibration method,and verifies the feasibility of the method through experiments.The calibration accuracy is high and can meet the requirements of existing industrial applications.(1)Aiming at the problems of poor human-computer interaction and low measurement efficiency in the field measurement of existing large-scale equipment assembly,a set of integrated helmet measuring instrument was designed,and the overall composition of the helmet measuring instrument and the design idea of the multi-camera positioning module were introduced.(2)Analyze and explain the positioning principle of multi-camera positioning module,introduce the imaging and distortion model of the large-field measurement camera,introduce the distortion factor into the pose calculation,and first solve the initial value of the pose.Iteratively optimizes the pose based on the L-M algorithm.(3)Analyze the characteristics of multi-camera positioning system,propose two calibration methods of multi-camera positioning system,introduce the calibration model of two calibration methods,and deduced the proposed multi-camera calibration principle in detail.The L-M algorithm is used to optimize the internal and external parameters of the camera system,and the error source of the calibration method is analyzed and simulated.(4)The two calibration methods were verified by experiments,and the software and hardware experimental platform was built.The experimental results show that the two methods are feasible and can meet the accuracy requirements of the existing work.