AC/DCC : Accurate Calibration of Dynamic Camera Clusters for Visual SLAM

Abstract

In order to relate information across cameras in a Dynamic Camera Cluster (DCC), an accurate time-varying set of extrinsic calibration transformations need to be determined. Previous calibration approaches rely solely on collecting measurements from a known fiducial target which limits calibration accuracy as insufficient excitation of the gimbal is achieved. In this paper, we improve DCC calibration accuracy by collecting measurements over the entire configuration space of the gimbal and achieve a 10X improvement in pixel re-projection error. We perform a joint optimization over the calibration parameters between any number of cameras and unknown joint angles using a pose-loop error optimization approach, thereby avoiding the need for overlapping fields-of-view. We test our method in simulation and provide a calibration sensitivity analysis for different levels of camera intrinsic and joint angle noise. In addition, we provide a novel analysis of the degenerate parameters in the calibration when joint angle values are unknown, which avoids situations in which the calibration cannot be uniquely recovered. The calibration code will be made available at https://github.com/TRAILab/AC-DCC.