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Open AccessArticle

A Height Estimation Approach for Terrain Following Flights from Monocular Vision

Department of Computer Science, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil
Department of Automation and Process Integration, Vale Institute of Technology, Ouro Preto 35400-000, Brazil
Author to whom correspondence should be addressed.
Academic Editors: Gabriel Oliver-Codina, Nuno Gracias and Antonio M. López
Sensors 2016, 16(12), 2071;
Received: 5 October 2016 / Revised: 22 November 2016 / Accepted: 29 November 2016 / Published: 6 December 2016
(This article belongs to the Special Issue Vision-Based Sensors in Field Robotics)
PDF [4759 KB, uploaded 6 December 2016]


In this paper, we present a monocular vision-based height estimation algorithm for terrain following flights. The impressive growth of Unmanned Aerial Vehicle (UAV) usage, notably in mapping applications, will soon require the creation of new technologies to enable these systems to better perceive their surroundings. Specifically, we chose to tackle the terrain following problem, as it is still unresolved for consumer available systems. Virtually every mapping aircraft carries a camera; therefore, we chose to exploit this in order to use presently available hardware to extract the height information toward performing terrain following flights. The proposed methodology consists of using optical flow to track features from videos obtained by the UAV, as well as its motion information to estimate the flying height. To determine if the height estimation is reliable, we trained a decision tree that takes the optical flow information as input and classifies whether the output is trustworthy or not. The classifier achieved accuracies of 80 % for positives and 90 % for negatives, while the height estimation algorithm presented good accuracy. View Full-Text
Keywords: UAV; terrain following flights; optical flow; computer vision; robotics UAV; terrain following flights; optical flow; computer vision; robotics

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Campos, I.S.G.; Nascimento, E.R.; Freitas, G.M.; Chaimowicz, L. A Height Estimation Approach for Terrain Following Flights from Monocular Vision. Sensors 2016, 16, 2071.

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