This paper proposes a novel approach that performs extrinsic parameter estimation of a camera installed in a man-made environment using a single image. The problem of extrinsic parameter calibration is identical to 6DoF (six-degrees of freedom) localization problem of the camera. We take advantage of line information that is usually present in the man-made environment such as inside of the building. Our approach only requires a flat surface map for a 3D environment model which can be easily obtained from the blueprint of the artificial environment (e.g., CAD data). In order to manage the complicated 6DoF search problem, we propose a novel image descriptor defined in quantized Hough space to perform 3D-2D matching process between line features from the 3D flat surface model and the 2D single image. The proposed method can robustly estimate the complete extrinsic parameters of the camera, as we demonstrate experimentally.
In this research, we propose a novel distortion-resistant visual odometry technique using a spherical camera, in order to provide localization for a UAV-based, bridge inspection support system. We take into account the distortion of the pixels during the calculation of the 2-frame essential matrix via feature-point correspondences. Then, we triangulate 3D points and use them for 3D registration of further frames in the sequence via a modified spherical error function. Via experiments conducted on a real bridge pillar, we demonstrate that the proposed approach greatly increases the accuracy of localization, resulting in an 8.6 times lower localization error.