How to weigh an elephant seal with one finger: a simple three-dimensional photogrammetric application
How to weigh an elephant seal with one finger: a simple three-dimensional photogrammetric application
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DOI：
10.3354/ab00135
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发表时间：
2009-01-01
期刊：
影响因子：
1.4
通讯作者：
Oosthuizen, W. Chris
中科院分区：
文献类型：
--
作者：
de Bruyn, P. J. Nico;Bester, Marthan N.;Oosthuizen, W. Chris
一些研究已经开发出间接估计海豹质量的摄影测量技术。不幸的是，这些技术通常被狭隘地描述为特定的现场场景或物种。许多需要复杂的、定制设计的设备或分析工具，这限制了它们的适用性。我们的目标是设计一种摄影测量技术，在各种野外情况下准确估计海豹的体积/质量，而不需要操纵动物和使用最少的设备。我们使用Photomodeler Pro三维建模软件估计了53只重的南方象海豹Mirouga Leonina的质量。这种方法的中心是根据动物周围的三维区域来估计动物的体积，而不是动物本身的特征，这种方法解放了与早期研究相关的限制。这种体积/质量估计不需要形态测量身体测量。我们提供的预测方程可以使质量估计相对于测量质量具有很高的置信度(根据现场情况，平均质量偏差的95%可信区间为+/-1.34到+/-3.83%)。只需一名摄影师手持一根测量棒和非定制的数码摄影设备，只需按一下按钮，就可以使用这项技术来确定野外任何地方的象海豹的质量。
Several studies have developed photogrammetric techniques for indirect mass estimation of seals. Unfortunately, these techniques are often narrowly delineated for specific field scenarios or species. Many require sophisticated, custom-designed equipment or analytical tools, limiting their applicability. We aimed to devise a photogrammetric technique for accurate volume/mass estimation of seals under a variety of field scenarios without manipulation of the animal and with minimal equipment. We used Photomodeler Pro 3-dimensional modelling software to estimate the mass of 53 weighed southern elephant seals Mirounga leonina. The method is centred on animal volume estimation in relation to the 3-dimensional area around it, rather than features of the animal itself, an approach that liberates limitations associated with earlier studies. No morphometric body measures are required for such volume/mass estimation. We offer predictive equations that allow high confidence in mass estimates relative to measured mass (95% confidence interval of mean deviation from measured mass is from +/- 1.34 to +/- 3.83% depending on the field scenario). A single photographer with a measuring stick and non-customised digital photographic equipment can use this technique to determine the mass of an elephant seal anywhere in the field with the push of a button.