Marine ecology progress series | |
Affordable and accurate stereo-video system for measuring dimensions underwater: a case study using oceanic whitetip sharks Carcharhinus longimanus | |
, Edward J. Brooks1  , Demian D. Chapman1  *, Aaron Olsen2  , Lucy A. Howey3  Caine R. Delacy4  | |
[1] Department of Marine Science, Florida International University, North Miami, FL 33181, USA;Department of Organismal Biology and Anatomy, University of Chicago, IL 60637, USA;Microwave Telemetry, Inc., 8835 Columbia 100 Parkway, Colombia, MD 21045, USA;Ocean First Education, 3015 Bluff St., Boulder, CO 80301, USA | |
关键词: Stereo-video; 2D calibration; Shark; Length estimation; Carcharhinus longimanus; Non-intrusive; Population demography; Dimensions; | |
DOI : 10.3354/meps12190 | |
学科分类:海洋学与技术 | |
来源: Inter-Research | |
【 摘 要 】
Non-intrusive and non-destructive acquisition of length measurements for marine megafauna is increasingly valuable given growing threats to many species’ long-term survival. Stereo videography provides a means of obtaining length data with minimal impact on the organism and minimal observer bias. However, for many researchers, there are still significant financial barriers to employing stereo videography. Small-action cameras have reduced costs, but camera calibration still requires significant investment in software and equipment. Here, we trial open source calibration procedures using the R package StereoMorph and a simple 2D checkerboard as a calibration object to test if this approach yields accurate length data. We used a stereo-video system comprising 2 GoPro™ cameras to estimate the lengths of known targets in a pool and the lengths of oceanic whitetip sharks Carcharhinus longimanus in situ. Sharks were restrained in water alongside a boat and measured with a tape measure for comparison with the stereo-video lengths. Both pool and field trials yielded accurate results comparable to previous studies using 3D calibration cubes. Stereo-video measurements of lengths >1 m had proportional errors of <1% in the pool and <3.0% (64.2 mm) in comparison with tape-measured lengths of sharks in the field. Our open source calibration methods and affordable GoPro™-based stereo-video system yielded measurements that are comparable to other systems that use 3D calibration techniques and more expensive cameras. Additionally, we improve on previous attempts of 2D calibration approaches.
【 授权许可】
Unknown
【 预 览 】
Files | Size | Format | View |
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RO201902186620542ZK.pdf | 8KB | download |