Marine Technology Ltd., Wiktora Roszczynialskiego 4-6, 81-521 Gdynia, Poland.
Department of Geodesy, Gdańsk University of Technology, Gabriela Narutowicza 11-12, 80-233 Gdańsk, Poland.
Sensors (Basel). 2022 Feb 25;22(5):1844. doi: 10.3390/s22051844.
Hydrographic surveys enable the acquisition and processing of bathymetric data, which after being plotted onto nautical charts, can help to ensure safety of navigation, monitor changes in the coastal zone, and assess hydro-engineering structure conditions. This study involves the measurement of waterbody depth, identification of the seabed shape and geomorphology, the coastline course, and the location of underwater obstacles. Hydroacoustic systems mounted on vessels are commonly used in bathymetric measurements. However, there is also an increasing use of Unmanned Aerial Vehicles (UAV) that can employ sensors such as LiDAR (Light Detection And Ranging) or cameras previously not applied in hydrography. Current systems based on photogrammetric and remote sensing methods enable the determination of shallow waterbody depth with no human intervention and, thus, significantly reduce the duration of measurements, especially when surveying large waterbodies. The aim of this publication is to present and compare methods for determining shallow waterbody depths based on an analysis of images taken by UAVs. The perspective demonstrates that photogrammetric techniques based on the SfM (Structure-from-Motion) and MVS (Multi-View Stereo) method allow high accuracies of depth measurements to be obtained. Errors due to the phenomenon of water-wave refraction remain the main limitation of these techniques. It was also proven that image processing based on the SfM-MVS method can be effectively combined with other measurement methods that enable the experimental determination of the parameters of signal propagation in water. The publication also points out that the Lyzenga, Satellite-Derived Bathymetry (SDB), and Stumpf methods allow satisfactory depth measurement results to be obtained. However, they require further testing, as do methods using the optical wave propagation properties.
水深测量可获取和处理水深数据，这些数据在标绘到海图上之后，可以帮助确保航行安全，监测沿海地区的变化，并评估水工程结构状况。本研究涉及水体深度测量、海底形状和地貌识别、海岸线走向以及水下障碍物位置的测量。船载水声学系统常用于水深测量。但是，也越来越多地使用无人机 (UAV)，它们可以使用激光雷达 (LiDAR) 或以前未应用于水深测量的相机等传感器。当前基于摄影测量和遥感方法的系统能够在无人干预的情况下确定浅水水体的深度，从而大大缩短测量时间，尤其是在测量大型水体时。本出版物的目的是介绍和比较基于分析无人机拍摄图像确定浅水水体深度的方法。研究表明，基于 SfM（运动结构）和 MVS（多视点立体）方法的摄影测量技术可以实现高精度的水深测量。水波折射现象引起的误差仍然是这些技术的主要限制因素。研究还证明，基于 SfM-MVS 方法的图像处理可以有效地与其他测量方法结合使用，从而可以对水中信号传播参数进行实验确定。该出版物还指出，Lyzenga、卫星测深 (SDB) 和 Stumpf 方法可以获得令人满意的深度测量结果。但是，它们需要进一步测试，就像使用光学波传播特性的方法一样。
