WaterScenes: A Multi-Task 4D Radar-Camera Fusion Dataset and Benchmark for Autonomous Driving on Water Surfaces

Autonomous driving on water surfaces plays an essential role in executing hazardous and time-consuming missions, such as maritime surveillance, survivors rescue, environmental monitoring, hydrography mapping and waste cleaning. This work presents WaterScenes, the first multi-task 4D radar-camera fusion dataset for autonomous driving on water surfaces. Equipped with a 4D radar and a monocular camera, our Unmanned Surface Vehicle (USV) proffers all-weather solutions for discerning object-related information, including color, shape, texture, range, velocity, azimuth, and elevation. Focusing on typical static and dynamic objects on water surfaces, we label the camera images and radar point clouds at pixel-level and point-level, respectively. In addition to basic perception tasks, such as object detection, instance segmentation and semantic segmentation, we also provide annotations for free-space segmentation and waterline segmentation. Leveraging the multi-task and multi-modal data, we conduct numerous experiments on the single modality of radar and camera, as well as the fused modalities. Results demonstrate that 4D radar-camera fusion can considerably enhance the robustness of perception on water surfaces, especially in adverse lighting and weather conditions. WaterScenes dataset is public on https://waterscenes.github.io

Field Testing of a Stochastic Planner for ASV Navigation Using Satellite Images

We introduce a multi-sensor navigation system for autonomous surface vessels (ASV) intended for water-quality monitoring in freshwater lakes. Our mission planner uses satellite imagery as a prior map, formulating offline a mission-level policy for global navigation of the ASV and enabling autonomous online execution via local perception and local planning modules. A significant challenge is posed by the inconsistencies in traversability estimation between satellite images and real lakes, due to environmental effects such as wind, aquatic vegetation, shallow waters, and fluctuating water levels. Hence, we specifically modelled these traversability uncertainties as stochastic edges in a graph and optimized for a mission-level policy that minimizes the expected total travel distance. To execute the policy, we propose a modern local planner architecture that processes sensor inputs and plans paths to execute the high-level policy under uncertain traversability conditions. Our system was tested on three km-scale missions on a Northern Ontario lake, demonstrating that our GPS-, vision-, and sonar-enabled ASV system can effectively execute the mission-level policy and disambiguate the traversability of stochastic edges. Finally, we provide insights gained from practical field experience and offer several future directions to enhance the overall reliability of ASV navigation systems.Comment: 33 pages, 20 figures. Project website https://pcctp.github.io. arXiv admin note: text overlap with arXiv:2209.1186

Detecting fish aggregations from reef habitats mapped with high resolution side scan sonar imagery

As part of a multibeam and side scan sonar (SSS) benthic survey of the Marine Conservation District (MCD) south of St. Thomas, USVI and the seasonal closed areas in St. Croix—Lang Bank (LB) for red hind (Epinephelus guttatus) and the Mutton Snapper (MS) (Lutjanus analis) area—we extracted signals from water column targets that represent individual and aggregated fish over various benthic habitats encountered in the SSS imagery. The survey covered a total of 18 km2 throughout the federal jurisdiction fishery management areas. The complementary set of 28 habitat classification digital maps covered a total of 5,462.3 ha; MCDW (West) accounted for 45% of that area, and MCDE (East) 26%, LB 17%, and MS the remaining 13%. With the exception of MS, corals and gorgonians on consolidated habitats were significantly more abundant than submerged aquatic vegetation (SAV) on unconsolidated sediments or unconsolidated sediments. Continuous coral habitat was the most abundant consolidated habitat for both MCDW and MCDE (41% and 43% respectively). Consolidated habitats in LB and MS predominantly consisted of gorgonian plain habitat with 95% and 83% respectively. Coral limestone habitat was more abundant than coral patch habitat; it was found near the shelf break in MS, MCDW, and MCDE. Coral limestone and coral patch habitats only covered LB minimally. The high spatial resolution (0.15 m) of the acquired imagery allowed the detection of differing fish aggregation (FA) types. The largest FA densities were located at MCDW and MCDE over coral communities that occupy up to 70% of the bottom cover. Counts of unidentified swimming objects (USOs), likely representing individual fish, were similar among locations and occurred primarily over sand and shelf edge areas. Fish aggregation school sizes were significantly smaller at MS than the other three locations (MCDW, MCDE, and LB). This study shows the advantages of utilizing SSS in determining fish distributions and density

Charting Nigerian Waters for Safer Navigation

In pursuit of Nigeria’s, international obligations on maritime safety, the elimination of dangers to search and rescue efforts in our coastal waters, environmental pollution and destruction of maritime habitats, and hide-out for sea-borne criminal elements, the Federal Ministry of Transport through the National Maritime Authority (NMA), entered into an agreement on June 16, 2003, with Humber Marine Werks Limited (HMW) for Consultancy on Removal of Wrecks and Derelicts in Nigerian Waterways aimed the contract to conduct a hydrographic survey of the Lagos Ports Area; a critical input to quotations for actual removal of wrecks by contractors to be nominated by the Ministry.Intentando respetar las obligaciones internacionales de Nigeria en relaciôn con la seguridad marîtima; la eliminaciôn de peligros en los esfuerzos de bûsqueda y salvamento en nuestras aguas costeras; la contaminaciôn marina y la destrucciôn de habitat marinos, y los escondidos elementos criminales llevados a cabo en el mar, el Ministerio Federal de Transporte, a través de la Autoridad Marîtima Nacional (AMN), llegô a un acuerdo el 16 de Junio del 2003 con la empresa ‘Humber Marine Werks Limited’ (HMW) para su Asesoramiento sobre la Supresiôn de Restos de Naufragios y Objetos abandonados en las Vîas Navegables Nigerianas. El objetivo del contrato fue dirigir un levantamiento hidrogrâfico de la zona portuaria de Lagos; una contribuciôn critica para la cotizaciôn de la remociôn de restos de naufragios por parte de los contratistas a ser designados por el Ministerio. Esta es la primera de cuatro fases de contratos de levantamientos.A l 'appui des obligations du Nigéria en matière de sécurité maritime, pour l'élimination des dangers présents lors des efforts de recherche et de sauvetage dans nos eaux côtières, pour lutter contre la pollution environnementale et la destruction des habitats maritimes, et pour contrer la dissimulation d'éléments criminels à bord, le Ministère fédéral des Transports, parle biais de TAutorité maritime nationale, a conclu un accord, le 16 juin 2003, avec la société Humber Marine Werks Limited (HMW) pour des services de consultant en rapport avec l'en lèvement des épaves et des navires abandonnés dans les voies navigables nigérianes. Ce contrat a pour objet d'exécuter un levé hydrographique de la zone des ports Lagos; une contribution essentielle aux devis pour l ’enlèvement des épaves par des sociétés contractées par le Ministère. Il s'agit de la première phase de quatre phases de levés devant être réalisés sous contrat

Fouled yachts : a vector for marine invasive alien species to South African shores?

Biofouling on recreational yachts is an important vector for marine invasive alien species (MIAS) in many countries. There are various characteristics of a vessel that make it more susceptible to hull fouling. Yachts in three Western Cape marinas were surveyed to assess extent of fouling, hull maintenance patterns, travel history and yacht-owner awareness of MIAS issues

Assessment of tropical cyclone-induced shoreline and riverbank changes at the Rufiji Delta using satellite remote sensing methods

The study aimed at quantifying changes in shoreline and riverbanks caused by tropical cyclones (TCs) and associated rainfall in the Rufiji Delta, southern Tanzania. Long term changes of the shoreline and riverbanks were analysed using medium resolution (Landsat TM and ETM) satellite imagery (1991, 1997 and 2007), while short-term changes (2013 to 2014) were analysed using high resolution (Pleiades) satellite imagery. Delineation of the shoreline and riverbank changes were accomplished through the analysis of appropriate coloured image composites, Sobel filtering and maximum likelihood classification of land cover. Analysis of Landsat data showed a relatively higher magnitude of erosion between 1991 and 2007, followed by minor changes between 1997 and 2007. Simbauranga was the most severely eroding site, with an estimated magnitude of erosion of 83 to 100 m during the study period. The maximum magnitude of short-term changes of the riverbanks were estimated at about 31 m2. Apart from the erosion of the riverbanks, other changes were the conversion of water to vegetation covered areas (amounting to approximately 200 m2). Short-term shoreline changes were up to 206 m with higher magnitude of accretion (142 m) than erosion (-4 m). The study conclusively calls for further detailed research on shoreline and riverbank changes based on the impacts of TCs on land cover

Virtual aids to navigation

There are many examples of master, bridge crew and pilot errors in navigation causing grounding under adverse circumstances that were known and published in official notices and records. Also dangerous are hazards to navigation resulting from dynamic changes within the marine environment, inadequate surveys and charts. This research attempts to reduce grounding and allision incidents and increase safety of navigation by expanding mariner situational awareness at and below the waterline using new technology and developing methods for the creation, implementation and display of Virtual Aids to Navigation (AtoN) and related navigation information. This approach has widespread significance beyond commonly encountered navigation situations. Increased vessel navigation activity in the Arctic and sub-Arctic regions engenders risk due, in part, to the inability to place navigational aids and buoys in constantly changing ice conditions. Similar conditions exist in tropical regions where sinker placement to moor buoys in sensitive environmental areas with coral reefs is problematic. Underdeveloped regions also lack assets and infrastructure needed to provide adequate navigation services, and infrastructure can also rapidly perish in developed regions during times of war and natural disaster. This research exploits rapidly developing advances in environmental sensing technology, evolving capabilities and improved methods for reporting real time environmental data that can substantially expand electronic navigation aid availability and improve knowledge of undersea terrain and imminent hazards to navigation that may adversely affect ship operations. This is most needed in areas where physical aids to navigation are scarce or non-existent as well as in areas where vessel traffic is congested. Research to expand related vessel capabilities is accomplished to overcome limitations in existing and planned electronic aids, expanding global capabilities and resources at relatively low-cost. New methods for sensor fusion are also explored to vi reduce overall complexity and improve integration with other navigation systems with the goal of simplifying navigation tasks. An additional goal is to supplement training program content by expanding technical resources and capabilities within the confines of existing International Convention on Standards for Training, Certification and Watchkeeping for Seafarers (STCW) requirements, while improving safety by providing new techniques to enhance situational awareness

Structure From Motion Methodology Captures Seasonal Influences on Coastal Bluff Erosion and Landslide Hazards in Casco Bay, ME

Shoreline erosion in response to rising sea level is a global problem. Recognizing the need for observational data on coastal bluff recession in Casco Bay, Maine, we employed Structure from Motion (SfM) photogrammetric methods in a dynamic intertidal environment. Evaluating the method as a means to measure and monitor dynamic geomorphological changes occurring at a coastal bluff shows that a spatial resolution of centimeters over an area of 10’s to 100’s of meters can be attained at relatively low cost. The efficient methodology allows for frequent surveys at an operational scale, leading to greater temporal resolution and quantification of bluff erosion activity that supports understanding of the local geohazard. With the greater temporal resolution gained from this evaluation additional inferences are made towards seasonal controls on bluff geomorphology. In the local temperate climate, the dominant erosional actor is characteristically linked to seasonal transitions. Given the urgency of coastal erosion, the lack of local records, and newfound feasibility of repeat surveys, Structure from Motion presents the opportunity to address the uncertainty of bluff instability with an approach that accounts for quantified change over time. Observations were evaluated with respect to: 1) the coastal bluff erosion cycle conceptual model; 2) local landslide hazards; and 3) preservation of a shoreline status record

Lacustrine ice-margin dynamics in west Greenland

There has been a progressive increase in the number and area of ice-marginal lakes along the western margin of the Greenland Ice Sheet (GrIS) since the late 1980s. Ice-marginal lake formation and growth have been widely associated with accelerated rates of mass loss and terminus recession at alpine glaciers, yet their impacts on the GrIS have remained unquantified. This thesis therefore investigated the influence of ice-marginal lakes on ice-margin dynamics in west Greenland at multiple spatial and temporal scales, using both established remote sensing techniques and the novel integration of time-lapse photography with Structure-from-Motion and Multi-View Stereo. A regional-decadal scale analysis of ice-margin change along a ~5000 km length of the GrIS revealed that lake-terminating ice-margins receded faster than their terrestrial counterparts between 1987 and 2015. In addition, the rate of recession at lake-terminating ice-margins accelerated over the study period and increasingly outpaced recession at terrestrial ice-margins. Altitude, latitude, lake area and the length of the lake – ice-margin interface were also identified as significant controls on rates of lake-terminating ice-margin recession. Local-seasonal scale ice-margin dynamics were investigated using the first continuous year-round volumetric record of calving at a lacustrine ice-margin. These data highlighted two distinct calving regimes; with melt-undercutting driving high calving rates under ice-free lake conditions, and force imbalances at the ice-cliff driving low calving rates when the lake was frozen. These results are important because they demonstrate that ice-marginal lakes are key regulators of ice-margin dynamics at the GrIS. The quantitative data derived through this study provide an empirical foundation upon which modelling efforts can incorporate the influence of ice-marginal processes. This is particularly pertinent given that rates of mass loss and recession at lake-terminating margins of the GrIS are likely to accelerate in coming decades in response to continued ice-marginal lake expansion and a lengthening melt season