SkyAnchor：从无位姿地面视角序列更新度量尺度航空三维高斯场景
SkyAnchor: Updating Metric-scale Aerial 3D Gaussian Scenes from Unposed Ground-View Sequences
- University of Liverpool（利物浦大学）
- The Ohio State University（俄亥俄州立大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
SkyAnchor利用现有航空场景作为固定脚手架，通过锚点约束的子地图和光束法平差，将无位姿地面序列配准并更新度量尺度三维高斯场景，在七个真实场景上验证了精确轨迹与高质量渲染。
AI中文摘要：
我们研究如何利用新采集的无位姿地面视角序列来更新预先构建的航空场景。航空场景已包含可靠的度量尺度运动恢复结构（SfM）重建和预训练的三维高斯泼溅（3DGS）模型，而地面视角序列是之后采集的，用于补充街道级外观，但其相机位姿和全局尺度未知。将该序列配准到航空SfM重建具有挑战性，因为单图像跨视角定位较为脆弱，且长轨迹容易发生漂移。为应对这些挑战，我们提出SkyAnchor，它将现有航空场景视为固定的脚手架，用于地面视角配准和场景更新，而非从头联合重建航空和地面图像。它首先针对经过几何验证的航空支持数据，对短组连续地面帧进行定位，生成稀疏锚点位姿。随后，通过锚点约束的子地图恢复完整地面轨迹，在增量配准和光束法平差过程中固定前后锚点位姿。最后，在保留航空视角的同时插入过滤后的地面高斯，并进行轻量级联合细化。在七个真实航空-地面场景上的实验表明，该方法能够生成精确的度量地面轨迹，并更新三维高斯场景，同时具备强大的航空和地面视角渲染质量。
英文摘要：
We study how to update a pre-built aerial scene with a newly captured, unposed ground-view sequence. The aerial scene already contains a reliable metric Structure-from-Motion (SfM) reconstruction and a pre-trained 3D Gaussian Splatting (3DGS) model, whereas the ground-view sequence is collected later to add street-level appearance but has unknown camera poses and global scale. Registering this sequence to the aerial SfM reconstruction is challenging because single-image cross-view localization is brittle and long trajectories are prone to drift. To address these challenges, we present SkyAnchor, which treats the existing aerial scene as a fixed scaffold for ground-view registration and scene update instead of jointly reconstructing aerial and ground imagery from scratch. It first localizes short groups of consecutive ground frames against geometrically verified aerial support, producing sparse anchor poses. It then recovers the full ground trajectory with anchor-constrained submaps, fixing the front and rear anchor poses during incremental registration and bundle adjustment. Finally, it inserts filtered ground Gaussians while preserving the aerial view, followed by lightweight joint refinement. Experiments on seven real aerial--ground scenes show accurate metric ground trajectories and updated 3D Gaussian scenes with strong aerial- and ground-view rendering quality.
