Speakers Bio & Abstract

Francesco Nex Assistant Professor
University of Twente
The Netherlands

Francesco Nex received his master degree in Environmental Engineering at the Politecnico di Torino in 2006 and a PhD in Geomatics in 2010 in the same University. From 2011 to 2015 he was with the 3DOM (3D Optical Metrology) unit of FBK (Bruno Kessler Foundation, Trento, Italy) working as Post-Doc in the CIEM Project (co-founded Marie-Curie Actions 7th F.P.) from 2011 to 2014 and then as Researcher in the 3DSolarWeb project and the RAPIDMAP project (Concert-Japan Project funded by EU 7th F.P.). In 2015, Francesco moved to the University of Twente, where he is currently Assistant Professor at the faculty of Geo-Information Science and Earth Observation (ITC), department of Earth Observation Science (EOS). His main research interests concern the use of oblique imagery and UAV platforms as well as the automation in feature extraction from 3D geo-referenced data. He is currently involved in three European research projects dealing with oblique and UAV images. Francesco is author of over 70 publications in journals and international conferences. He is the secretary of the ICWG I/Vb (Unmanned Aerial Vehicles: sensors and applications) of the International Society of Photogrammetry and Remote Sensing (ISPRS) and he is Principal Investigator of the scientific initiative A new benchmark dataset for multi-platform very high resolution photogrammetry.Abstract
Oblique aerial images: potentialities, applications and best practices
The use of oblique imagery has become a standard for many civil and mapping applications, thanks to the development of airborne digital multi-camera systems, as proposed by many companies (Blomoblique, IGI, Leica, Midas, Pictometry, Vexcel/Microsoft, VisionMap, etc.). The indisputable virtue of oblique photography lies in its simplicity of interpretation and understanding for inexperienced users, closing the gap between aerial and terrestrial acquisitions and allowing their use in very different applications, such as building detection and modelling, building structural damage classification, road updating and land administration services, etc. However, the practical utility of this data is obvious but automated processing is still a challenge. Oblique imagery differs from traditional nadir images in terms of occlusions, varying image scale and illumination, and traditional photogrammetric workflows need to be adapted. A general overview of the current commercial systems and an automated workflow for the orientation of large oblique blocks will be given in the first part of the presentation. The precision and accuracy of the image orientation of oblique blocks compared to the nadir case will be discussed in detail. The quality of the photogrammetric point clouds and the completeness of the corresponding 3D city models will be then addressed. Several case studies concerning urban modelling, 3D map updating and building damage assessment will be finally presented reporting the substantial technical and operational benefits of this kind of data. Perspectives, potentialities, pitfalls and best practices for achieving satisfactory results will be discussed as well.