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Please use this identifier to cite or link to this item: http://hdl.handle.net/10204/6130

Title: A study of the sensitivity of long-range passive ranging techniques to atmospheric scintillation
Authors: De Villiers, J
Wilson, F
Nicolls, F
Keywords: Depth from defocus
Depth from focus
Scintillation
Heat shimmer
Passive ranging
Issue Date: Apr-2012
Publisher: SPIE
Citation: De Villiers, J, Wilson, F and Nicolls, F. A study of the sensitivity of long-range passive ranging techniques to atmospheric scintillation. SPIE Defense Security and Sensing 2012, Baltimore, Maryland, USA, 23-27 April 2012. Published in Visual Information Processing XXI, Proceedings of SPIE Volume: 8399, Neifeld, MA and Ashok, A (editors), doi: 10.1117/12.920358
Series/Report no.: Workflow;9101
Abstract: This work aims to quantify and improve the sensitivity of monocular passive ranging techniques in sequences that are degraded by the the quasi-periodic inter frame motion and localised blurring associated with atmospheric scintillation. Ranges from tens of meters up to 1km in uncontrolled outdoor conditions were investigated. This work has application in surveillance, border control, artillery, and the autonomous navigation of ground vehicles. A field trial with long focal length, large aperture cameras was held. The targets were placed at known distances and a scintillometer was used to measure the turbulence between the cameras and each target. A variety of depth from defocus and depth from focus algorithms were applied to a the video sequences to determine range to the targets. Increasing levels of atmospheric turbulence were observed ranging from no turbulence to mild, moderate and severe turbulence. Algorithms for the mitigation of atmospheric turbulence were applied to the recorded video sequences. The passive ranging techniques were then applied to the turbulence-mitigated video sequences and the results compared to that of the raw sequences. Finally, findings regarding the best performing combination of ranging and mitigation techniques to use under different scintillation conditions are presented.
Description: Copyright: 2012 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic electronic or print reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.
URI: http://spiedigitallibrary.org/data/Conferences/SPIEP/67608/83990O.pdf
http://hdl.handle.net/10204/6130
ISBN: 9780819490773
ISSN: 0277-786X.
Appears in Collections:Optronic sensor systems
Advanced mathematical modelling and simulation
General science, engineering & technology

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