PL‐Pose: robust camera localisation based on combined point and line features using control images

Camera localisation is an essential task in the field of computer vision. The objective is to determine the precise position and orientation of one newly introduced camera station based on a collection of control images that are geographically referenced. Traditional feature‐based approaches have been found to face difficulties when confronted with the task of localising images that exhibit significant disparities in viewpoint. Modern deep learning approaches, on the contrary, aim to directly regress camera poses from input image content, being holistic to remedy the problem of viewpoint disparities. This paper posits that although deep networks possess the ability to learn robust and invariant visual features, the incorporation of geometry models can provide rigorous constraints in the process of pose estimation. Following the classic structure‐from‐motion (SfM) pipeline, we propose a PL‐Pose framework to perform camera localisation. First, to improve feature correlations for images with large viewpoint disparities, we perform the combination of point and line features based on a deep learning framework and geometric relation of wireframes. Then, a cost function is constructed using the combined point and line features in order to impose constraints on the bundle adjustment process. Finally, the camera pose parameters and 3D points are estimated through an iterative optimisation process. We verify the accuracy of the PL‐Pose approach through the utilisation of two datasets, that is, the publicly available S3DIS dataset and the self‐collected dataset CUMTB_Campus. The experimental results demonstrate that in both indoor and outdoor scenes, our PL‐Pose method can achieve localisation errors of less than 1 m for 82% of the test points. In contrast, the other four comparison methods yield a best result of merely 72%. Meanwhile, the PL‐Pose method can successfully obtain the camera pose parameters in all the scenes with small or large viewpoint disparities, indicating its good stability and adaptability.