Underwater image sensing is directly affected by the change in illuminance towards a camera caused by the refraction of light in different media. In this study, the convergence of a near-field point light source in water is analyzed using a light propagation model. The photometric stereo (PS) formula is determined based on an accurate estimation of the illuminance entering the camera. An underwater PS system is designed to verify the proposed method's feasibility. The experimental results demonstrate improved accuracy in normal calculation. This helps achieve accurate underwater 3D reconstruction of objects that is suitable for underwater surface microdefect detection.
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http://dx.doi.org/10.1364/AO.476003 | DOI Listing |
Soft Robot
January 2025
Department of Mechanical and Nuclear Engineering, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates.
Soft robots and bioinspired systems have revolutionized robot design by incorporating flexibility and deformable materials inspired by nature's ingenious designs. Similar to many robotic applications, sensing and perception are paramount to enable soft robots to adeptly navigate the unpredictable real world, ensuring safe interactions with both humans and the environment. Despite recent progress, soft robot sensorization still faces significant challenges due to the virtual infinite degrees of freedom of the system and the need for efficient computational models capable of estimating valuable information from sensor data.
View Article and Find Full Text PDFJ Acoust Soc Am
January 2025
Key Laboratory of Underwater Acoustic Communication and Marine Information Technology of the Ministry of Education, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China.
Odontocetes are capable of dynamically changing their echolocation clicks to efficiently detect targets, and learning their clicking strategy can facilitate the design of man-made detecting signals. In this study, we developed deep convolutional generative adversarial networks guided by an acoustic feature vector (AF-DCGANs) to synthesize narrowband clicks of the finless porpoise (Neophocaena phocaenoides sunameri) and broadband clicks of the bottlenose dolphins (Tursiops truncatus). The average short-time objective intelligibility (STOI), spectral correlation coefficient (Spe-CORR), waveform correlation coefficient (Wave-CORR), and dynamic time warping distance (DTW-Distance) of the synthetic clicks were 0.
View Article and Find Full Text PDFJ Acoust Soc Am
January 2025
School of Integrated Circuits, Tsinghua University, Beijing 100084, China.
In shallow water, reverberation complicates the detection of low-intensity, variable-echo moving targets, such as divers. Traditional methods often fail to distinguish these targets from reverberation, and data-driven methods are constrained by the limited data on intruding targets. This paper introduces the online robust principal component analysis and multimodal anomaly detection (ORMAD) method to address these challenges.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Longpan Road 159, Nanjing 210037, China. Electronic address:
The weak cohesive strength of tissue adhesives hinders their practical applications. To overcome this challenge, we develop a green bio-adhesive that balances both cohesion and adhesion, drawing inspiration from the natural adhesion mechanisms of mussels. This bio-adhesive, referred to as OTS, was ingeniously crafted through the co-assembly of multi-surface-charged chitin nanofibers (OAChN) and tannic acid (TA), integrated with silk fibroin (SF), resulting in a material with enhanced cohesive strength and robust adhesive properties.
View Article and Find Full Text PDFEar Nose Throat J
January 2025
Department of Otolaryngology, Northern Jiangsu People's Hospital, Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou, PR China.
This study aimed to compare the efficacy of continuous perfusion of underwater bone grinding combined with a -shaped incision versus a microscopic posterior ear incision in the treatment of attic cholesteatoma. Clinical trials were prospective studies from the Northern Jiangsu People's Hospital. Adult patients with middle ear cholesteatoma requiring ear surgery agreed to participate between September 2019 and September 2023 (age > 18).
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