Reduced resolution of polarized images makes it difficult to distinguish detailed polarization information and limits the ability identify small targets weak signals. A possible way handle this problem is super-resolution (SR), which aims obtain a high-resolution image from low-resolution one. However, compared with traditional intensity-mode SR, SR more challenging because channels their nonlinear cross-links need be considered as well intensity reconstructed simultaneously. This paper...

Polarization characteristics are significantly crucial for tasks in various fields, including the remote sensing of oceans and atmosphere, as well polarization LIDAR polarimetric imaging scattering media. Many metrics (such degree polarization, angle diattenuation, depolarization) have been proposed to enrich characterization improve task performance media; yet, their related efficacy is limited, especially high turbidity conditions. The indices purity (IPPs), three different depolarization...

In this Letter, we propose an attention-based neural network specially designed for the challenging task of polarimetric image denoising. particular, channel attention mechanism is used to effectively extract features underlying images by rescaling contributions channels in network. addition, also design adaptive polarization loss make focus on information. Experiments show that our method can well restore details flooded serious noise and outperforms previous methods. Moreover, revealed visually.

Utilizing the polarization analysis in underwater imaging can effectively suppress scattered light and help to restore target signals turbid water. Neural network-based solutions also boost performance of polarimetric imaging, while most existing networks are pure data driven which suffer from ignoring physical mode. In this paper, we proposed an effective solution that informed model constrains into well-designed deep neural network. Especially compared with conventional model,...

As an important marine environmental parameter, sound velocity greatly affects the propagation characteristics in ocean. In surveying work, prompt and low-cost acquisition of accurate speed profiles (SSP) is immense significance for improving measurement positioning accuracy acoustic equipment ensuring underwater wireless communication. To address problem not being able to glean SSP real time, we propose a convolution long short-term memory neural network (Conv-LSTM) which combines (LSTM)...

Numerical simulations have been used in this paper to study the propulsion device of a wave glider based on an oscillating hydrofoil, which profile pitching and heaving motion prescribed for sake simplicity. A grid model two-dimensional NACA0012 hydrofoil was built by using dynamic moving mesh technology Computational Fluid Dynamics (CFD) software FLUENT corresponding mathematical has also established. First, sinusoidal pitching, effects amplitude reduced frequency were investigated. As...

A numerical investigation is conducted to study the propulsive performance of semi-active flapping foil wave glider, where heaving smotion fully prescribed, and pitching motion determined by hydrodynamic force torsion spring. mesh for two-dimensional NACA0012 with Reynolds number Re = 42000 produced, a dynamic sliding interface are used in computation. The influences reduced frequency, spring stiffness, critical amplitude on characteristics systematically investigated. We find that there...

Ultrasound has been proven to be a valid tool for ranging, especially in water. In this paper, we design high-resolution ultrasonic ranging system that uses thin laser beam as an sensor. The sensing provides noncontact method ultrasound detection based on acousto-optic diffraction. Unlike conventional methods, the transmitted from transducer is recorded reference signal when it first passes through laser. It can used improve accuracy and resolution of time-of-flight (TOF) by...

In this paper, we propose a method aiming to measure the absolute distance via slope of inter-mode beat phase by sweeping repetition frequency comb. The presented approach breaks inertial thinking extremely stable comb spacing, and bulky phase-locking circuit is not required. particular, non-ambiguity range can be expanded infinite. To verify performance method, series experiments have been devised in different scenarios. Compared with reference values, experimental results show differences...

Color polarimetric imaging could provide multi-dimensional information that provides physical properties related to object shape, surface roughness, etc. Therefore, it has been widely used in various instrumentation and measurement applications, such as 3D measurement, detection, navigation. However, compared conventional color images, images have a lower signal-to-noise ratio are more sensitive noise, which leads unpleasant noisy destroys polarization analysis performance. Moreover, the...

Abstract Underwater acoustics is of fundamental importance for marine science and technology. However, acoustic waves transmitted by state‐of‐the‐art underwater systems are not inherently phase locked, which hinders the development For example, precision distance measurement can only achieve centimeter level. As a versatile tool, optical frequency combs have enabled revolutionary progress in metrology measurement. In parallel with combs, here, generation fully stabilized, reported,...

Underwater images always suffer from low contrast and color distortion due to the wavelength-dependent scattering absorption effects caused by particles existing in turbid water, especially high turbidity conditions. Based on polarization properties of backscattering light, polarimetric methods can estimate intensity level transmittance media. Accordingly, they separate target signal undesired ones achieve high-quality imaging. In addition, learning-based are effective for gray-model image...

A numerical investigation on the propulsion performance of semi-active flapping foil wave glider with different mass ratio and damping coefficient is investigated. The commercial CFD software Fluent used to solve URANS equations around by Finite Volume Method. mesh 2D NACA0012 Reynolds number Re = 42,000 in all simulations. We first analyze effect mean output power efficiency note that variation ratio, decreases slightly. Besides, we find has a noticeable influence coefficient, determined...

The benthic structure of seamounts is critical for understanding the ecological environment and assessing influence resource exploitation. However, characteristics seamount, especially guyot, are still far from being clearly understood. For first time, we carried out detailed hydroacoustic mapping in conjunction with surficial sediment sampling underwater video recording to investigate geomorphical biological Pallada Guyot Western Pacific Ocean (WPO). We utilized Benthic Terrain Modeler...

Accurate acquisition for the positions of waterlines plays a critical role in coastline extraction. However, waterline extraction from high-resolution images is very challenging task because it easily influenced by complex background. To fulfill task, two types vision transformers, segmentation transformers (SETR) and semantic (SegFormer), are introduced as an early exploration potential estimate effects methods, we collect web map services, annotations created manually training test....

It is extremely challenging to rapidly and accurately extract target echo photon signals from massive point clouds with strong background noise without any prior geographic information. Herein, we propose a fast surface detection method realized by combining the improved density-dimension algorithm (DDA) Kalman filtering (KF), termed DDA-KF algorithm, for high rate (BNR) improve extraction of spacecraft platforms. The results showed that exhibited good adaptability terrain slope variations,...

As a novel remote-sensing method, the Global Navigation Satellite System-Reflectometry (GNSS-R) can utilize large number of reflected GNSS opportunity signals for sea ice observation. The first analysis spaceborne GNSS-R data from Chinese Jilin-1 Wideband-01B (J1-01B) Mission is carried out. 72 days delay-Doppler maps (DDMs) obtained global positioning system-reflectometry (GPS-R) and BeiDou navigation satellite (BDS-R) utilized detection. In addition to traditional pixel (pn) power...