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Proceedings Paper

Land-based infrared imagery for marine mammal detection
Author(s): Joseph Graber; Jim Thomson; Brian Polagye; Andrew Jessup
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Paper Abstract

A land-based infrared (IR) camera is used to detect endangered Southern Resident killer whales in Puget Sound, Washington, USA. The observations are motivated by a proposed tidal energy pilot project, which will be required to monitor for environmental effects. Potential monitoring methods also include visual observation, passive acoustics, and active acoustics. The effectiveness of observations in the infrared spectrum is compared to observations in the visible spectrum to assess the viability of infrared imagery for cetacean detection and classification. Imagery was obtained at Lime Kiln Park, Washington from 7/6/10-7/9/10 using a FLIR Thermovision A40M infrared camera (7.5-14μm, 37°HFOV, 320x240 pixels) under ideal atmospheric conditions (clear skies, calm seas, and wind speed 0-4 m/s). Whales were detected during both day (9 detections) and night (75 detections) at distances ranging from 42 to 162 m. The temperature contrast between dorsal fins and the sea surface ranged from 0.5 to 4.6 °C. Differences in emissivity from sea surface to dorsal fin are shown to aid detection at high incidence angles (near grazing). A comparison to theory is presented, and observed deviations from theory are investigated. A guide for infrared camera selection based on site geometry and desired target size is presented, with specific considerations regarding marine mammal detection. Atmospheric conditions required to use visible and infrared cameras for marine mammal detection are established and compared with 2008 meteorological data for the proposed tidal energy site. Using conservative assumptions, infrared observations are predicted to provide a 74% increase in hours of possible detection, compared with visual observations.

Paper Details

Date Published: 15 September 2011
PDF: 11 pages
Proc. SPIE 8156, Remote Sensing and Modeling of Ecosystems for Sustainability VIII, 81560B (15 September 2011); doi: 10.1117/12.892787
Show Author Affiliations
Joseph Graber, Univ. of Washington (United States)
Jim Thomson, Univ. of Washington (United States)
Brian Polagye, Univ. of Washington (United States)
Andrew Jessup, Univ. of Washington (United States)


Published in SPIE Proceedings Vol. 8156:
Remote Sensing and Modeling of Ecosystems for Sustainability VIII
Wei Gao; Thomas J. Jackson; Jinnian Wang; Ni-Bin Chang, Editor(s)

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