A Method of Measuring the Absolute Position and Attitude Pa- Rameters of A Moving Rigid Body Using A Monocular Camera
Abstract
Shengjun Guo, Zuoxi Zhao, Linyang Guo and Min Wei
A method of measuring the absolute pose parameters of a moving rigid body using a monocular camera is proposed, aiming at addressing calibration difficulties and inconsistencies of repeated measurements of the rigid-body pose for a camera having a varying focal length. The pro- posed method does not require calibration beforehand. Using more than six non-coplanar control points symmetrically arranged in the rigid-body and world coordinate systems, the matrices of ro- tation and translation between the camera and two coordinate systems are obtained and the abso- lute pose of the rigid body measured. In this paper, formulas of the absolute pose measurement of a moving rigid body are deduced systematically and the complete implementation is presented. Position and attitude measurement experiments carried out on a three-axis precision turntable show that the average absolute error in the attitude angle of a moving rigid body measured by an uncali- brated camera at different positions changes by no more than 0.2 degrees. Analysis of the three- dimensional coordinate errors of the centroid of a moving rigid body shows little deviation in meas- urements made at three camera positions, with the maximum deviation of the average absolute error being 0.53 cm and the maximum deviation of the standard deviation being 0.66 cm. The pro-posed method can measure the absolute pose of a rigid body and is insensitive to the position of the camera in the measurement process. This work thus provides guidance for the repeated measure- ment of the absolute pose of a moving rigid body using a monocular camera.turns affect the rate of entropy generation.