Enhancing Georeferencing and Mosaicking Techniques over Water Surfaces with High-Resolution Unmanned Aerial Vehicle (UAV) Imagery

Remote Sensing, Journal Year: 2024, Volume and Issue: 16(2), P. 290 - 290

Published: Jan. 11, 2024

Aquatic ecosystems are crucial in preserving biodiversity, regulating biogeochemical cycles, and sustaining human life; however, their resilience against climate change anthropogenic stressors remains poorly understood. Recently, unmanned aerial vehicles (UAVs) have become a vital monitoring tool, bridging the gap between satellite imagery ground-based observations coastal marine environments with high spatial resolution. The dynamic nature of water surfaces poses challenge for photogrammetric techniques due to absence fixed reference points. Addressing these issues, this study introduces an innovative, efficient, accurate workflow georeferencing mosaicking that overcomes previous limitations. Using open-source Python libraries, employs direct produce georeferenced orthomosaic integrates multiple UAV captures, has been tested locations worldwide optical RGB, thermal, multispectral imagery. best case achieved Root Mean Square Error 4.52 m standard deviation 2.51 accuracy, thus UAV’s centimeter-scale This represents significant advancement processes, resolving major limitation facing technology remote observation local-scale phenomena over surfaces.

Language: Английский

---

Remote Data for Mapping and Monitoring Coastal Phenomena and Parameters: A Systematic Review

Remote Sensing, Journal Year: 2024, Volume and Issue: 16(3), P. 446 - 446

Published: Jan. 23, 2024

Since 1971, remote sensing techniques have been used to map and monitor phenomena parameters of the coastal zone. However, updated reviews only considered one phenomenon, parameter, data source, platform, or geographic region. No review has offered an overview that can be accurately mapped monitored with data. This systematic was performed achieve this purpose. A total 15,141 papers published from January 2021 June 2023 were identified. The 1475 most cited screened, 502 eligible included. Web Science Scopus databases searched using all possible combinations between two groups keywords: geographical names in areas platforms. demonstrated that, date, many (103) (39) (e.g., coastline land use cover changes, climate change, urban sprawl). Moreover, authors validated 91% retrieved parameters, 39 1158 times (88% combined together other parameters), 75% over time, 69% several compared results each available products. They obtained 48% different methods, their 17% GIS model techniques. In conclusion, addressed requirements needed more effectively analyze employing integrated approaches: they data, merged

Language: Английский

---

Water-Quality Monitoring with a UAV-Mounted Multispectral Camera in Coastal Waters

Remote Sensing, Journal Year: 2022, Volume and Issue: 15(1), P. 237 - 237

Published: Dec. 31, 2022

Remote-sensing ocean colour studies have already been used to determine coastal water quality, biodiversity, and nutrient availability. In recent years, Unmanned Aerial Vehicles (UAVs) equipped with multispectral sensors, originally designed for agriculture applications, also enabled water-quality of waters. However, since the sea surface is constantly changing, commonly photogrammetric methods fail when applied UAV images captured over areas. this work, we evaluate applicability a five-band sensor mounted on derive scientifically valuable parameters such as chlorophyll-a (Chl-a) concentration total suspended solids (TSS), including new Python workflow manual generation an orthomosaic in aquatic areas exclusively based sensor’s metadata. We show details two different sites along Maltese coastline centimetre-scale, improving existing approximations that are available region through Sentinel-3 OLCI imagery at much lower spatial resolution 300 m. The Chl-a TSS values derived studied regions were within expected ranges varied between 0 3 mg/m3 10 20 mg/m3, respectively. Spectral comparisons carried out some statistics calculations RMSE, MAE, or bias order validate obtained results.

Language: Английский

---

UAV-based remote sensing of turbidity in coastal environment for regulatory monitoring and assessment

Marine Pollution Bulletin, Journal Year: 2023, Volume and Issue: 196, P. 115482 - 115482

Published: Oct. 19, 2023

Language: Английский

---

Nutrientscape ecology: a whole-system framework to support the understanding and management of coastal nutrient connectivity

Landscape Ecology, Journal Year: 2025, Volume and Issue: 40(3)

Published: Feb. 19, 2025

Language: Английский

---

Experimental verification of seafloor crustal deformation observations by UAV-based GNSS-A

Scientific Reports, Journal Year: 2023, Volume and Issue: 13(1)

Published: March 13, 2023

The Global Navigation Satellite System-Acoustic ranging combination technique (GNSS-A) is the only geodetic observation method that can precisely detect absolute horizontal and vertical seafloor crustal deformations at centimetre scale. GNSS-A has detected many geophysical phenomena expected to make great contributions earthquake disaster prevention science geodesy. However, current methods use vessels buoys suffer from high cost or poor real-time performance, which leads low frequency delays in obtaining transmitting information. To overcome these problems, a new sea surface platform needed. Here, we present an unmanned aerial vehicle (UAV) system developed for surveys capable of landing on surface. Submetre-level positioning achieved based single-frequency GNSS data acquired over actual site. UAV-based allows high-frequency, near deployment, low-cost observations. This could be deployed acquire high-frequency observations with centimetre-scale accuracies when using dual-frequency GNSS.

Language: Английский

---

Observational evidence of diapycnal upwelling within a sloping submarine canyon

Research Square (Research Square), Journal Year: 2023, Volume and Issue: unknown

Published: Oct. 20, 2023

Small-scale turbulent mixing drives the upwelling of deep water masses in abyssal ocean as part global overturning circulation (Wunsch & Ferrari 2004). However, processes leading to and pathways through which this occurs remain insufficiently understood. Recent observational theoretical work suggests that may be focused bottom boundary layers on ocean’s sloping seafloor; however, direct evidence is lacking (Ledwell et al. 2000, St. Laurent 2001, 2016, de Lavergne 2016). Here, we present observations from a near-bottom dye release within canyon North Atlantic continental slope showing across density surfaces at rate 250 +/- 75 m/day over three days, ∼10,000 times higher than average value required account for ∼30 Sv globally (Munk 1966). The vigourous coupled with adiabatic exchange near-boundary interior fluid. These results provide strong, bottom-focused diapycnal ocean, supporting previous suggestions topographic features, such canyons, leads upwelling.

Language: Английский

---

Developing a Generalizable Spectral Classifier for Rhodamine Detection in Aquatic Environments

Remote Sensing, Journal Year: 2024, Volume and Issue: 16(16), P. 3090 - 3090

Published: Aug. 22, 2024

In environmental studies, rhodamine dyes are commonly used to trace water movements and pollutant dispersion. Remote sensing techniques offer a promising approach detecting estimating its concentration, enhancing our understanding of dynamics. However, research is needed address more complex environments, particularly optically shallow waters, where bottom reflectance can significantly influence the spectral response rhodamine. Therefore, this study proposes novel approach: transferring pre-trained classifiers develop generalizable method across different conditions without need for in situ calibration. Various samples incorporating distilled seawater on light dark backgrounds were analyzed. Spectral analysis identified critical detection regions (400–500 nm 550–650 nm) concentration. Significant variations observed between backgrounds, highlighting necessity precise background characterization waters. Enhanced by Sequential Feature Selector, classification models achieved robust accuracy (>90%) distinguishing concentrations, effective under controlled laboratory conditions. While band transfer was successful (>80%), posed challenge. Strategies such as combining diverse sample sets applying first derivative prevent overfitting improved model generalizability, surpassing 85% three four scenarios. methodology provides us with classifier that be various scenarios requiring recalibration. Future aims expand dataset variability enhance applicability conditions, thereby advancing remote capabilities dynamics, monitoring pollution control.

Language: Английский

---

A Framework for Survey Planning Using Portable Unmanned Aerial Vehicles (pUAVs) in Coastal Hydro-Environment

Remote Sensing, Journal Year: 2022, Volume and Issue: 14(9), P. 2283 - 2283

Published: May 9, 2022

Recently, remote sensing using survey-grade UAVs has been gaining tremendous momentum in applications for the coastal hydro-environment. UAV-based provides high spatial and temporal resolutions flexible operational availability compared to other means, such as satellite imagery or point-based situ measurements. As strict requirements government regulations are imposed every UAV survey, detailed survey planning is essential ensure safe operations seamless coordination with activities. This study established a comprehensive framework of efficient deployments areas, which was based on recent on-site experiences portable unmanned aerial vehicle (pUAV) that carrying heavyweight spectral sensor. The classified into three main categories: (i) pre-survey considerations (i.e., administrative preparation airframe details); (ii) execution strategies parameters contingency planning); (iii) environmental effects weather marine conditions). implementation verification were performed UAV–airborne exercise water quality monitoring Singapore. encountered challenges mitigation practices developed from actual field integrated advance ease deployment improve acquisition process high-quality images.

Language: Английский

---

Near-Surface Dispersion and Current Observations by Dye, Drifter, and HF Radar in Coastal Water

Published: April 9, 2024

This study explores the near-surface dispersion mechanisms of contaminants in coastal waters, leveraging a comprehensive method that includes using dye and drifters as tracers, coupled with diverse observational platforms like drones, satellites, in-situ sampling, HF radar. The aim is to deepen our understanding surface currents' impact on contaminant dispersion, thereby improving predictive models for environmental incident management, including pollutant releases. Rhodamine WT dye, chosen its significant fluorescent properties detectability, along drifter data, allowed us investigate dynamics physical phenomena such Ekman current, Stokes drift, wind-driven currents. Our research emphasizes importance integrating scalar tracers Lagrangian markers experimental designs, revealing differential behaviors due vertical shear caused by current drift. elongation direction patch aligns during slow conditions. Analytical calculations shear, based closely matched those derived from tracer observations. Over 7-hour experiment, diffusivity water was observed at 2×10-4 m2/s, horizontal eddy reached order 1 m2/s 1000m length scale. Particle tracking demonstrate while radar currents can effectively predict trajectories near surface, incorporating currents, windage, essential more accurate prediction fate floats.

Language: Английский

---