UAV-based tilt photogrammetry for fast and accuracy 3D terrain acquisition

Abstract:

Terrain correction is an important step in electromagnetic induction surveys no matter for ground or airborne EM methods. Modern 3D modeling and inversion techniques also require high accuracy and continuous 3D terrain data. Ground based real-time kinematic (RTK) measurement or satellite based synthetic aperture radar interferometry (InSAR) can give a good accuracy but with very expensive cost for a quite large survey area. In this abstract, we show a UAV-based tilt photogrammetry method. This is a optical imaging method with 5 cameras under a UAV. Each time we take 5 photos at a same position in the air. A large amount of continued photos can be obtained along the flight survey lines. All photos can be digitalized and measured with aerial triangulation. A measurable 3D visual digital model is built. The digital elevation model (DEM) is also generated at the same time. The accuracy in latitude, longitude and elevation are all good enough to build an EM surface model. The progress can either be independently taken or be done together with airborne or semi-airborne surveys. We show a real case 3D model acquired in Guangxi, China. The model is used to simulated semi-airborne transient electromagnetic response in 3D with complex terrain.