A Collaborative Stereo Camera with Two UAVs for Long-Distance Mapping of Urban Buildings

For a swarm of Unmanned Aerial Vehicle (UAV), long-distance visual mapping is advantageous for pre-planning navigation paths in unknown urban building environments. This work leverages two cameras on two UAVs to build a wide- baseline collaborative stereo camera, which can construct a navigable mesh map for remote building obstacles. We present a complete framework of the collaborative stereo camera for long-distance mapping, including online extrinsic parameter estimation of the stereo camera, real-time cross-camera feature association, and semantic mesh map generation of remote build- ings. Extensive simulations and real-world experiments verify the effectiveness of the collaborative stereo camera. With a 3m baseline, the collaborative stereo camera achieves long-distance mapping of buildings (20m ∼50m) away with a relative error of approximately 10%. The constructed remote map enables UAVs to pre-detect large obstacles and pre-plan navigation paths in large-scale building environments. Hopefully, this work can provide a novel and practical approach for collaborative visual tasks of UAV swarm. Video - https://youtu.be/a0kj-1zb6KI