Perspective-n-point pose measurement with two line array cameras

Abstract

For the existing monocular vision methods of pose (or position and orientation) measurement based on the Perspective-n-Point problem, camera calibrations and image corrections are complicated and difficult due to the lens distortion. Additionally, as their theoretical models, the pinhole imaging model and the collinear equation only offer an ideal approximation for the imaging process of the area array camera. Thus, the measurement possesses inevitable systematic errors. To avoid these problems, a new pose measuring method is proposed, which replaces the area array camera and its collinear equation with two line array cameras and their incident light plane equations, respectively. For these two line array cameras, their mechanical assembly requirements and calibration steps are also analysed; they only require that the two optical centre lines of their cylindrical lenses be perpendicular to each other, and only need to be calibrated for the relationship between the coordinate of the image line and the incident angle of the incident light plane. The experiment results of P4P pose measurement with the proposed method showed only significant random errors and no significant systematic error, confirming that this method has eliminated the problems caused by the image distortion and model approximation.