A Novel Vision-Based Pose Measurement Method Considering the Refraction of Light

Abstract

Nowadays, due to the advantages of non-contact and high-speed, vision-based pose measurements have been widely used for aircraft performance testing in a wind tunnel. However, usually glass ports are used to protect cameras against the high-speed airflow influence, which will lead to a big measurement error. In this paper, to further improve the vision-based pose measurement accuracy, an imaging model which considers the refraction light of the observation window was proposed. In this method, a nonlinear camera calibration model considering the refraction brought by the wind tunnel observation window, was established first. What’s more, a new method for the linear calibration of the normal vector of the glass observation window was presented. Then, combining with the proposed matching method based on coplanarity constraint, the six pose parameters of the falling target could be calculated. Finally, the experimental setup was established to conduct the pose measurement study in the laboratory, and the results satisfied the application requirements. Besides, experiments for verifying the vision measurement accuracy were also performed, and the results indicated that the displacement and angle measurement accuracy approximately increased by 57% and 33.6%, respectively, which showed the high accuracy of the proposed method.

DoF-Dependent and Equal-Partition Based Lens Distortion Modeling and Calibration Method for Close-Range Photogrammetry

“…The former can be generally divided into three types: self-calibration method [ 15 ], active calibration method, and traditional calibration method [ 16 ]. Among the traditional ones, Zhang’s calibration method [ 17 ] and its improved method [ 18 , 19 , 20 ], used widely in industry and scientific research, are the most popular. In this coupled-calibration method, the distortion parameters are calculated by performing a full-scale optimization for all parameters.…”

A Decoupled Unified Observation Method of Stochastic Multidimensional Vibration for Wind Tunnel Models

“…During data acquisition tests for an aircraft's overall performance, the aircraft model is mounted by the long cantilever tail-support [1]. Under extreme test conditions with high attack angles, the aircraft model is subject to disturbances of complex unstable airflow [2,3], thereby inducing the aircraft model to undergo serious stochastic multidimensional vibration [4]. These aerodynamic characteristics cannot be tested at all if the vibration is not effectively suppressed.…”