SealNet: A fully-automated pack-ice seal detection pipeline for sub-meter satellite imagery
SealNet: A fully-automated pack-ice seal detection pipeline for sub-meter satellite imagery
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DOI：
10.1016/j.rse.2019.111617
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发表时间：
2020-03-15
影响因子：
13.5
通讯作者：
Lynch, H. J.
中科院分区：
文献类型：
--
作者：
Goncalves, B. C.;Spitzbart, B.;Lynch, H. J.
南极浮冰海豹是四种真海豹（海豹科）的统称，作为南极磷虾（长额磷虾）分布广泛的捕食者，在南大洋食物网中起着关键作用。由于它们呈环极分布，且其栖息地偏远而广阔，人们对其种群数量知之甚少。估算浮冰海豹的种群数量和趋势对于了解南大洋生态系统将如何应对诸如气候变化导致的海冰减少和磷虾捕捞等威胁至关重要。我们提出了一个利用“世界观 - 3”卫星图像和卷积神经网络的功能性浮冰海豹检测流程，该流程可对海豹中心点进行计数和定位。我们提出了一种新的卷积神经网络架构，它通过将语义分割热图与二分类相结合，并通过回归进行计数来检测物体。与人类专家的共识计数相比，我们的流程可定位超过30%的海豹，并将海豹检测所需时间减少95%（假设仅使用一个图形处理器）。虽然更大的训练集和持续的算法开发无疑会提高分类准确性，但我们的流程（可轻松适用于在亚米级卫星图像中可见的其他大型动物）展示了机器学习在极大地扩展我们对浮冰海豹进行定期调查的能力方面的潜力，并且在此过程中，将有助于正在进行的对浮冰海豹进行监测的国际努力。
Antarctic pack-ice seals, a group of four species of true seals (Phocidae), play a pivotal role in the Southern Ocean foodweb as wide-ranging predators of Antarctic krill (Euphausia superba). Due to their circumpolar distribution and the remoteness and vastness of their habitat, little is known about their population sizes. Estimating pack-ice seal population sizes and trends is key to understanding how the Southern Ocean ecosystem will react to threats such as climate change driven sea ice loss and krill fishing. We present a functional pack-ice seal detection pipeline using Worldview-3 imagery and a Convolutional Neural Network that counts and locates seal centroids. We propose a new CNN architecture that detects objects by combining semantic segmentation heatmaps with binary classification and counting by regression. Our pipeline locates over 30% of seals, when compared to consensus counts from human experts, and reduces the time required for seal detection by 95% (assuming just a single GPU). While larger training sets and continued algorithm development will no doubt improve classification accuracy, our pipeline, which can be easily adapted for other large-bodied animals visible in sub-meter satellite imagery, demonstrates the potential for machine learning to vastly expand our capacity for regular pack-ice seal surveys and, in doing so, will contribute to ongoing international efforts to monitor pack-ice seals.