The bigger picture: developing a low-cost graphical user interface to process drone imagery of tidal stream environments

Unmanned Aerial Vehicles (UAVs), or drones, offer the ability to collect cost-effective fine-scale imagery that is suitable for the capture of concurrent hydrodynamic and faunal data within tidal stream environments. This is a necessary stage of information gathering to inform tidal energy device design, advise control and maintenance strategies and better inform environmental consenting processes. For this study a total of sixty-three UAV surveys were undertaken within the Inner Sound of the Pentland Firth, Scotland, UK, over two 4-day periods in 2016 and 2018. The aims of this data collection effort were to characterise bathymetrically driven hydrodynamic features, comprising of kolk-boil distribution, presence, and area, as well as marine life such as seabird distributions, presence, and orientation relative to the flow. To achieve this, a method to extract quantifiable metrics from UAV imagery was required. This paper details the processes and methodology to create a graphical user interface (GUI) to provide these outputs rather than examining specific results. It includes an explanation of the criteria that the GUI needed to meet to be able to process the imagery, a description of the workflow and an explanation of the sub-routines required such as image registration and calibration. The outputs of the GUI, and their relevance to tidal energy developments, are also discussed. Finally, this paper details future work incorporating computer vision techniques to improve the accuracy, reliability, and processing speed of the GUI.