Towards fast 3D reconstruction of urban areas from aerial nadir images for a near real-time remote sensing system

At Fraunhofer IOSB, a concept for a near real-time airborne 3D mapping system for disaster management and security applications was proposed [1]. In addition to an Airborne Laser Scanner (ALS), a RGB camera facing nadir is installed on that platform. Subsequent RBG pictures are used for reconstructing urban scenes, and an ALS point cloud is used as a reference data set to evaluate this work. For in-flight applications, the implemented 3D reconstruction from overlapping nadir images should operate in near real-time. This paper focuses on computational performance and quality considerations of 3D reconstruction of urban scenes with aerial images. Different subpixel disparity levels are considered for generating 3D models. The run-time and quality for depth map generation with two methods are evaluated as well. The PatchMatch Stereo (PMS) algorithm is compared with the Semi-Global Matching (SGM), the most popular algorithm for 3D reconstruction.