Uav Photogrammetry in Remote Areas – 3d Modeling of Drapham Dzong Bhutan

Abstract

ABSTRACT:The Buddhist fortress Drapham Dzong is located in the Bumthang District in central Bhutan on a mountain ridge at approximately 2930 m altitude. A surveying mission was carried out with the goal to produce a textured 3D model of the site, together with a conventional 2D map and an orthophoto. The remote and exposed location of the site makes traditional surveying, including terrestrial laser-scanning a tedious undertaking. Aerial images of reasonable quality are not available in Bhutan. Satellite images, even of very high resolution (50cm footprint) do not show sufficient detail for the modelling of the man-made structures. Therefore this project leads itself very well to the use of an appropriate UAV. This paper describes briefly the raw data acquisition by UAV and terrestrial images, and then focuses on the procedures for data processing. The 3D model of the man-made objects is embedded into a large area model of the environment, generated from a GeoEye-1 stereo model. Overall, the project is a typical example of a multi-image concept, making use of imagery of quite different resolutions (satellite, UAV, terrestrial). Given a textured accurate 3D model, 2D maps and orthoimages are nothing but derivatives of this general product. The project also shows how lightweight equipment can be used in remote and not easily accessible areas for surveying and 3D modelling purposes.

Accuracy Assessment in Structure From Motion 3d Reconstruction From Uav-Born Images: The Influence of the Data Processing Methods

“…Bolognesi et al, 2014;Santise et al, 2014;Nocerino et al, 2014;Colomina & Molina, 2014;Eisenbeiß, 2009;Nex & Remondino, 2014). Checks of rendering precision can be performed either by comparing SfM-derived models against reference models with known precision, or by measuring the deviation of control points identified on the model and surveyed with traditional topographical methods and instruments [Bolognesi et al, 2014;Gruen et al, 2012;Santise et al, 2014]. The knowledge of these precision levels is most important especially for the integration of SfM derived models with others derived by different sensors and/or methodologies (laser scanning, classic photogrammetry, etc.).…”

Building and site reconstruction from small scale unmanned aerial vehicles (UAV's)

“…the facades of buildings. Image data acquisition using UAV's can provide the necessary views to 978-1-4799-6652-3/15/$31.00 c 2015 IEEE complement traditional aerial or satellite data, however, so far UAV's have only been used to reconstruct isolated buildings or sites [6], [7], [8], [9], [10] and have not been employed for large scale mapping. The listed works have in common that UAV's are used to capture images of an isolated site to produce a 3D reconstruction.…”

Locating flood embankments using SAR time series: A proof of concept

“…Instead research has concentrated on finding undocumented structures with LiDAR (Briese, 2004;Czuba et al, 2015;Krüger and Meinel, 2008) or using DEM data with active contour methods to outline dike locations (Gang et al, 2003). Additionally, the use of photogrammetry and SAR products from Uninhabited Aerial Vehicle SAR (UAVSAR) is becoming more widespread to support local (high-resolution/low-cost) embankment structural health monitoring (Carvajal et al, 2011;Dabbiru et al, 2014;Marapareddy et al, 2016) or to enhance multi-spectral satellite observations (Gruen et al, 2012). The studies which do utilise radar satellite data, particularly the data from the second generation of SAR satellites, focus on the structural changes of buildings, dams, wetlands, railway infrastructure and cultural heritage areas (Chang et al, 2014;Milillo et al, 2016;Nico et al, 2015;Schmitt and Brisco 2013;Schmitt et al, 2014;Tomás et al, 2013;White et al, 2015).…”