Improving marine growth estimates using 3D photogrammetry

海上基础设施，包括石油和天然气以及可再生能源设施，迅速被各种各样的动物和植物（海藻）所占据，这里称为“海洋生长”。海洋生物的性质和范围对近海基础设施的性能和完整性具有工程和生态后果。从工程角度来看，海生物改变了关键结构特征，影响操作（如拖曳力和加载力）和退役阶段（如导管架提升/拖曳）的性能。从生态学的角度来看，海洋生物是近海结构物提供的“礁石效应”的基础;海洋生物提供生态系统服务，如水过滤、食物供应和庇护所（例如，为鱼类提供庇护所）。海上能源的规模以及相关结构的安装和拆除规模相当大，其中包括新风电场的调试（预计到2050年欧洲将有多达50，000台风力涡轮机）以及石油和天然气结构的退役（超过20%的北海资产将在10年内退役）。工业需要监测其装置上海洋生物（MG）的四个方面。这些方面是海洋生长类型（例如贻贝、珊瑚、海葵）质量、体积和表面粗糙度。需要准确估计这些方面，以便（1）为考虑海洋生物影响的工程决策提供信息，（2）优化清洁制度和规划，（3）为退役时的起重作业提供信息，以及（4）组织海洋生物的处置。还需要对海洋增长进行估计，以了解近海结构提供的生态系统服务，从而了解安装和拆除基础设施的环境后果。监管机构和政策制定者也需要这些信息作为证据基础，以优化与同意的离岸活动有关的决策。目前，工业界采用一种简单的算法来估计海洋生物的厚度和质量。该算法经常导致预测和报告的MG质量之间的大幅高估（高达20倍）。目前的MG估计不佳导致高度的不确定性，例如在提升结构所需的设备方面，这种不确定性导致相当大的成本。我们的项目将建立在正在进行的研究，以评估生成和分析的可行性，3D图像来自使用远程操作的车辆获得的视频画面（ESTA）。我们将根据不同的MG类别（海藻，硬生长，如贻贝，和软生长，如海绵和海葵）校准从3D图像估计的MG体积。然后，我们将采取收集周围的石油和天然气结构，随后已退役，并清理，并比较我们的新MG估计与那些记录的退役场。这项可行性评估将最终产生最佳实践指南，以行业为最佳方法，以生成和使用3D图像评估MG。作为该项目的结果，最终用户组织中嵌入的知识将引导3D成像作为一种新型海洋生长评估工具的采用。

Offshore infrastructure, including oil and gas and renewables installations, are rapidly colonised by a diverse range of animals and plants (seaweeds), here referred to as 'marine growth'. The nature and extent of marine growth has both engineering and ecological consequences for the performance and integrity of offshore infrastructure. From an engineering perspective, marine growth changes critical structure characteristics affecting performance at both the operational (e.g. drag and loading forces) and decommissioning phases (e.g. jacket lifting/towing). From an ecological perspective, marine growth is the basis for the 'reef-effect' offered by offshore structures; marine growth provides ecosystem services such as water filtration, food provision and shelter (e.g. for commerical fish species). The scale of offshore energy, and the associated installation and removal of structures, is considerable and includes the commissioning of new wind-farms (up to 50,000 wind-turbines are projected by 2050 in Europe) and decommissioning of oil and gas structures (>20% of North Sea assets to be decommissioned within 10 years). Industry needs to monitor four aspects of the marine growth (MG) on their installations. These aspects are marine growth type (e.g. mussels, coral, anemones) mass, volume and surface roughness. Accurate estimation of these aspects is required in order to (1) inform engineering decisions that account for effects of marine growth, (2) optimise cleaning regimes and planning, (3) inform lifting operations at decommissioning and (4) organise disposal of the marine growth. Marine growth estimates are also required to understand the ecosystem-services offered by offshore structures and thus the environmental consequences of installing and removing infrastructure. This information is also required by regulators and policy-makers as an evidence base to optimise decision-making with respect to consenting offshore activities. Currently, industry employs a simple algorithm to estimate marine growth thickness and mass on their structures. This algorithm frequently results in substantial overestimates (up to a factor of 20) between predicted and reported MG mass. The current poor MG estimates result in a high degree of uncertainty, for example in the equipment necessary to lift a structure, and this uncertainty incurs considerable costs. Our project will build on on-going research to assess the feasibility of generating, and analysing, 3D images derived from video footage obtained using remotely operated vehicles (ROV). We will calibrate the MG volume estimated from the ROV-3D images against different MG categories (seaweed, hard-growth, such as mussels, and soft-growth, such as sponges and anemones). We will then take ROV footage gathered around oil and gas structures that have subsequently been decommissioning, and cleaned, and compare our new MG estimates against those recorded by the decommissioning yard. This feasibility assessment will culminate in the production of best-practice guidelines to industry for optimal methods to generate and use 3D images in assessing MG. The knowledge embedded in end-users organisations, as result of this project, will steer adoption of 3D imaging as a novel marine growth assessment tool.