Marine sampling field manual for towed underwater camera systems. In: Field Manuals for Marine Sampling to Monitor Australian Waters
Marine sampling field manual for towed underwater camera systems. In: Field Manuals for Marine Sampling to Monitor Australian Waters
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拖曳式水下摄像机系统的海洋采样现场手册。
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发表时间：
2018
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通讯作者：
A. Tyndall
中科院分区：
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作者：
A. Carroll;F. Althaus;R. Beaman;A. Friedman;I. Ierodiaconou;T. Ingleton;A. Jordan;Michelle Linklater;Jacquomo Monk;A. Post;R. Przeslawski;J. Smith;M. Stowar;M. Tran;A. Tyndall
自20世纪之交以来，各种配置的拖曳式水下摄像系统已被用于获取海底的视频和静止图像（Bicknell等人，2016）。这些系统部署在水面船只的电缆上，没有推进机制，通常具有前视倾斜和/或向下看的摄像头，可以记录存储并随后下载的图像。或者通过同轴电缆或光纤电缆将数据直接实时传输到地面（Bowden and Jones 2016, Durden et al. 2016a）。拖曳式水下摄像机不仅增加了收集标本的数据（第8,9章）；它们还提供了一种重要的非侵入性采样替代方法，在提取方法不必要或不合适的情况下，例如在敏感的深海栖息地（例如Althaus等人，2009年，Williams等人，2015年，Sherlock等人，2016年），或在海洋保护区重复采样（例如Lawrence等人，2015年）。拖曳式平台还具有额外的优势，可以沿着长达几公里的横断面提供经济有效的永久数据捕获，并可用于穿越高度异质的海底地形（Shortis等人，2007年，Sheehan等人，2016年）。拖曳系统获得的图像质量在很大程度上取决于海况和水的清澈度，这两者可能因地理位置、采样季节和潮汐影响程度而有很大差异。在深度大于30米的情况下，照明和相机规格对图像质量变得越来越重要。设备的质量和多功能性以及在海床上方保持一致的飞行高度也是影响图像质量和可用性的关键因素。
Towed underwater camera systems, of various configurations, have been used since the turn of the 20th century to acquire video and photographic still images of the seafloor (Bicknell et al. 2016) They are deployed on a cable from a surface vessel, have no propulsion mechanisms, and generally have forward-looking oblique and/or downward-looking cameras that either record images which are stored and subsequently downloaded, or transmit data directly to the surface in real-time via a coaxial or fibre optic cable (Bowden and Jones 2016, Durden et al. 2016a). Towed underwater cameras not only augment data from collected specimens (Chapter 8, 9); they also provide an important non-invasive sampling alternative where extractive methods are either unnecessary or unsuitable, such as in sensitive deep-sea habitats (e.g. Althaus et al. 2009, Williams et al. 2015, Sherlock et al. 2016), or for repeated sampling in marine reserves (e.g. Lawrence et al. 2015). Towed platforms also have the added advantage of providing cost-effective permanent data capture along transects that can be up to several kilometers in length and can be used to traverse highly heterogeneous seafloor topography (Shortis et al. 2007, Sheehan et al. 2016). The quality of imagery acquired by towed systems depends largely on sea conditions and water clarity, both of which may vary considerably depending on geographic location, season of sampling and extent of tidal influence. In depths greater than around 30 m, lighting and camera specifications become increasingly important to image quality. The quality and versatility of equipment and the maintenance of a consistent flying altitude above the seabed are also critical factors affecting image quality and usability.
Conventional underwater still photography and video imagery were initially applied by marine ecologists to collect basic qualitative data (e.g. simple visual assessment of seabed conditions to assess habitat type or dominant species), or often low-accuracy quantitative data estimated through the use of parallel lasers to define the scale of the images (see Harvey et al. 2002, Shortis et al. 2008, Durden et al. 2016a). Recent technological advancements have emerged that permit collection of high-resolution benthic imagery using versatile multifunctional towed platforms carrying a variety of camera systems (e.g. stereo-image measurement systems) and a range of other sensors (e.g. high-resolution multibeam and side-scan sonars, motion sensors, conductivity temperature and depth sensors, and subsea acoustic positioning systems) (Kocak et al., 2008, Rattray et al. 2014, Bowden and Jones 2016, Durden et al. 2016a, Logan et al. 2017). This technology, coupled with advances in camera resolution, positional accuracy, digital data processing and visualisation techniques, has enabled more quantitative and spatially-referenced studies of the seafloor. Calibrated stereo-imaging in particular has facilitated more reliable length measurements of mobile species, such as epibenthic invertebrates and demersal fish, and more accurate estimates of biomass and population distributions (Harvey et al. 2002, Shortis et al. 2009). Towed underwater imaging systems can be applied to acquire baseline data, evaluate benthic diversity, map benthic habitats, identify vulnerable communities, assess changes in biota, and support spatial and ecological modelling/monitoring.