1st Workshop on Maritime Computer Vision (MaCVi) 2023: Challenge Results

The 1$^{\text{st}}$ Workshop on Maritime Computer Vision (MaCVi) 2023 focused on maritime computer vision for Unmanned Aerial Vehicles (UAV) and Unmanned Surface Vehicle (USV), and organized several subchallenges in this domain: (i) UAV-based Maritime Object Detection, (ii) UAV-based Maritime Object Tracking, (iii) USV-based Maritime Obstacle Segmentation and (iv) USV-based Maritime Obstacle Detection. The subchallenges were based on the SeaDronesSee and MODS benchmarks. This report summarizes the main findings of the individual subchallenges and introduces a new benchmark, called SeaDronesSee Object Detection v2, which extends the previous benchmark by including more classes and footage. We provide statistical and qualitative analyses, and assess trends in the best-performing methodologies of over 130 submissions. The methods are summarized in the appendix. The datasets, evaluation code and the leaderboard are publicly available at https://seadronessee.cs.uni-tuebingen.de/macvi.Comment: MaCVi 2023 was part of WACV 2023. This report (38 pages) discusses the competition as part of MaCV

Study on UV-aging performance of fluorinated polymer coating and application on painted muds

The UV-aging tests were carried out on synthetic fluorinated polymer coating (poly (methyl methacrylate)-poly (dodecafluoroheptyl methacrylate), FP) to study its UV-aging mechanism, UV-aging resistance and application on painted muds with calcium carbonate, azurite, haematitum, mineral green and cinnabar pigments. The UV-aging mechanism was studied by Fourier infrared spectroscopy attenuated total reflection technique (ATR-FTIR) and x-ray photoelectron spectroscopy (XPS). The UV-aging resistance of FP was characterized by field emission scanning electron microscope (SEM), CR-400 color difference meter and static contact angle (SCA). The FP was applied on the painted muds samples and the protective efficacy was evaluated by measuring the chromatic variations(ΔE) and water contact angles of samples after treatment. The results of ATR-FTIR and XPS shown that FP only had microphase separation without chemical change after 360h of aging. After 360h of aging, the SEM shown that there were just some bumps on the FP film surface and further proved the phenomenon of microphase separation; the color change of the FP film was no difference (ΔE = 0.46); the FP film could retain adequate hydrophobicity (101.0°). After the painted muds samples were treated by FP, the color change of the calcium carbonate and haematitum was just noticeable difference (ΔE = 0.80 ∼ 1.49), while the color change of the azurite, mineral green and cinnabar was fairly large difference (ΔE = 4.4 ∼ 6.3); all pigments could maintain hydrophobicity at the end of aging. All the results demonstrated that the FP has excellent UV-aging resistance and could provide adequate protective efficacy for calcium carbonate and haematitum, but the protection efficacy for the azurite, mineral green and cinnabar is not ideal. Thus, it is believed that the FP can be used as a suitable UV resistant protective coating for calcium carbonate and haematitum

Aging mechanism and surface properties of Silica fluoropolymer coating and its application

The hydrothermal aging cycles experiment was carried out on synthetic Silica fluoropolymer coating (SiO _2 -FP). The hydrothermal aging mechanism, surface properties and protective efficacy on sandstones was studied. For comparison, the same study was conducted for commercial protective material acrylic resin Paraloid B72 (PB72). The hydrothermal aging mechanism was studied by Fourier infrared spectroscopy attenuated total reflection technique (ATR-FTIR) and x-ray photoelectron spectroscopy (XPS) technology. The surface properties were characterized by field emission scanning electron microscope (SEM), the CR-400 color difference meter, static contact angle and GMT6503 Electronic universal Tensile machine. The capillary water absorption, water absorption by complete immersion (CI) and water vapor permeability were measured to evaluate the protective efficacy on sandstones after treatment. The results of ATR-FTIR and XPS indicated that part of the ester groups in PB72 was hydrolysed and the chemical structure of SiO _2 -FP was not changed but only microphase separation occurred after 360 h of aging. After 360 h of aging, the PB72 film had obvious change and the SiO _2 -FP film only shown a minor change; the color change of PB72 film was very obvious and the color change of SiO _2 -FP film was within the acceptable range; the PB72 film changed from hydrophobic to hydrophilic and the SiO _2 -FP film still retained high hydrophobicity (119.3°); the SiO _2 -FP had a higher adhesive strength than PB72 at the end of aging. Compared with PB72, the SiO _2 -FP can obviously reduce the capillary water absorption and had a higher protective efficiency (97.25%), much lower soakage capacity (0.60%), higher water vapor permeability (267.0 ± 2) and less influence on the water vapor permeability. All the results demonstrated that the SiO _2 -FP has much better anti-aging ability and longer durability under hydrothermal condition. The SiO _2 -FP can provide adequate protection for sandstones. The SiO _2 -FP can be used as a suitable protective coating on sandstones

A facile route to obtain binary micro-nano roughness on composite coating surface

Binary micro-nano rough morphology or structure shows a significant influence on hydrophobicity and icing-resistivity of the surface of coating materials. The leading cause for the classic Cassie state superhydrophobicity is the high area fraction of micro/nano air mattresses being in direct contact with a measured droplet. In this work, the dependence of static hydrophobicity on weight content of commercial surface-hydrophobicity-modified nano-silica in fluoropolymer based composite coatings has been investigated in detail via detecting static water contact angle (CA). It was found that elevating the weight content of hydrophobic nano-silica could contribute to a higher surface roughness, a more compact binary micro-nano morphology and a larger area ratio of air mattresses due to a stronger hypothesized phase separation. As a result, the remarkably improved water CA of composite coatings far higher than the neat polymer coating was observed relying on coating composition. Fortunately, the maximum static water CA of 167° was obtained in composite coating loaded with 50 wt% of hydrophobic nano-silica. For gaining the desired high comprehensive performances, it was advised to introduce 30 wt% of nano-filler into polymer. This work might open a facile route to achieve the promising superhydrophobic and anti-icing materials

Preparation and Application of a Magnetic Oxidized Micro/Mesoporous Carbon with Efficient Adsorption for Cu(II) and Pb(II)

Water pollution is a worldwide problem that requires urgent attention and prevention and exceeding use of heavy-metal ions is one of the most harmful factors, which poses a serious threat to human health and the ecological environment. In this work, a magnetic oxidized micro/mesoporous carbon (MOMMC) was prepared for the easy separation of Cu(II) and Pb(II) from water. The dual-template method was used to prepare micro/mesoporous carbon using sucrose as the carbon source, silica nanoparticles formed by tetraethyl orthosilicate as the microporous templates, and triblock copolymer F127 as the mesoporous template. MOMMC was obtained by oxidation using potassium persulfate and then magnetized through in situ synthesis of Fe3O4 nanoparticles. FTIR, TG-DSC, XRD, TEM, SEM, nitrogen adsorption–desorption isotherms, zeta potential, and VSM were used to confirm the synthetic process, structure, and basic properties of MOMMC. The high-saturation magnetization (59.6 emu·g−1) of MOMMC indicated its easy and fast separation from water by an external magnetic field. Kinetics studies showed that the adsorption of Cu(II) and Pb(II) on MOMMC fit the pseudo-second-order model well. Isotherm studies showed that the adsorption behavior of Cu(II) was better described by the Langmuir model, and the adsorption behavior of Pb(II) was better described by both Langmuir and Redlich–Peterson models. MOMMC obtained efficient adsorption for Cu(II) and Pb(II) with the large adsorption capacity of 877.19 and 943.40 mg·g−1 according to the Langmuir adsorption isotherm equation, and a better selectivity for Pb(II) was observed in competitive adsorption. MOMMC still possessed a large adsorption capacity for Cu(II) and Pb(II) after three adsorption–desorption cycles. These findings show that MOMMC represents an excellent adsorption material for the efficient removal of heavy-metal ions