Fully Geometric Panoramic Localization
Authors: Junho Kim, Jiwon Jeong, Young Min Kim

We introduce a lightweight and accurate localization method that only utilizes the geometry of 2D-3D lines. Given a pre-captured 3D map our approach localizes a panorama image taking advantage of the holistic 360 degree view. The system mitigates potential privacy breaches or domain discrepancies by avoiding trained or hand-crafted visual descriptors. However as lines alone can be ambiguous we express distinctive yet compact spatial contexts from relationships between lines namely the dominant directions of parallel lines and the intersection between non-parallel lines. The resulting representations are efficient in processing time and memory compared to conventional visual descriptor-based methods. Given the groups of dominant line directions and their intersections we accelerate the search process to test thousands of pose candidates in less than a millisecond without sacrificing accuracy. We empirically show that the proposed 2D-3D matching can localize panoramas for challenging scenes with similar structures dramatic domain shifts or illumination changes. Our fully geometric approach does not involve extensive parameter tuning or neural network training making it a practical algorithm that can be readily deployed in the real world. Project page including the code is available through this link: https://82magnolia.github.io/fgpl/.