Open source structure-from-motion for aerial video

Structure-from-motion (SfM) is a well-studied problem in the computer vision field and is of particular interest for aerial imaging applications like mapping, terrain modeling, crop monitoring, etc. With the current rapid growth in the commercial UAV and small satellite markets, aerial SfM is becoming even more important. In recent years, free and open source software has enabled almost anyone to apply SfM to their data at no cost. Existing free packages are oriented toward processing unordered collections of photographs and are less efficient at processing ordered collections or video. They are also prone to failure with nearly planar scenes that often arise in aerial photography. While commercial solutions for aerial SfM exist, they are proprietary and expensive. This paper presents a new open source software toolkit named MAP-Tk that targets SfM for aerial video. It exploits temporal continuity and the aerial nature of the data to speed up and improve feature tracking, loop closure, and bundle adjustment. The system is highly configurable and modular. Dynamic plugins provide state-of-the art algorithms from other open source projects like OpenCV, VXL, and Ceres Solver. This paper presents the modular system design, user interface, novel algorithms exploiting aerial video, and results on various aerial data sets.