Forward-looking sonar is a commonly used underwater detection device. However, due to the complex environment, small target areas, and blurred features, accuracy poor not conducive quickly finding desired targets. In recent years, deep learning has developed rapidly, semantic segmentation network models have shown strong performance, with enormous application potential in forward-looking image segmentation. A lightweight multiscale attention proposed this article for real-time of system. The...

A multimode microcavity sensor based on a self-interference microring resonator is demonstrated experimentally. The proposed sensing method implemented by recording wideband transmission spectra that consist of multiple resonant modes. It different from the previous dissipative scheme, which aims at measuring depth changes single mode in microcavity. Here, combining mechanism and machine learning algorithm, information extracted broadband spectrum can be efficiently fused to estimate target...

Ultraviolet visible spectroscopy can realize the detection of chemical oxygen demand (COD), especially for low concentration levels due to its high sensitivity, but issue insufficient real water sample data has always been a challenge owing probability occurrence actual pollution events. However, in existing methods, generated absorption spectra do not conform situations as former neglect spectral characteristics. On other hand, diversity and complexity are restricted because information...

3-D imaging sonar is crucial in the exploration of marine resources, and development portable device with high quality real-time performance general trend. However, traditional framework methods are limited by huge amount computation brought high-quality imaging, making it difficult to implement engineering. To address this issue, we develop system an algorithm-hardware co-designed way. An ultrawideband distributed parallel subarray beamforming algorithm (UWBDPS) proposed for acoustic...

In recent years, ultraviolet-visible spectroscopy has been widely used for measurements of water quality in seawater, because full spectrum contains large amounts information. NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> can be detected 220-230 nm, and chemical oxygen demand (COD) total organic carbon (TOC) 280-290 nm. visible spectrum, color, turbidity suspended solids (TSS) measured. We presented a environmental multi-parameter...

This paper describes a new turbidity transducer based on color measurement. The absorbance of solutions reflects the absorption and scattering suspended particle for incident light which could determine solutions. experimental results indicate that there are good linear relationships between chromaticity turbidity. way is suitable continuous monitoring water in wide range.

We propose an adaptive weighted high frequency iterative algorithm for a fractional-order total variation (FrTV) approach with nonlocal regularization to alleviate image deterioration and eliminate staircase artifacts, which result from the (TV) method. The gradients are reweighted in iterations adaptively when we decompose into low components using pre-processing technique. is introduced our method based on means (NLM) filtering, contains prior structural information suppress artifacts. An...

Abstract We demonstrate the rotation and oscillation of single-charged vortex (SCV) double-charged (DCV) in two-dimensional (2D) optically induced square photonic lattices under single-site excitation with appropriate self-focusing nonlinearity conditions. Numerical analysis shows that SCV can self-trap into a localized gap soliton mode resides first Bragg reflection gap, for which is nested centrally rotating square-shaped optical envelope four peaks always appear at corners. Whereas DCV...

Abstract We propose an approach for achieving various centrosymmetric shapes by employing hybrid polarized Bessel–Gaussian (HPBG) beams with multi-vortex phases, which are obtained embedding a few first-order off-axis topological charges into vortices separated equal arc lengths of circle. According to the Debye–Wolf electromagnetic diffraction formula (which is routinely used describe focusing high numerical aperture optical systems), we investigate evolution tightly focused intensity...

The development of real-time 3-D underwater imaging systems with large planar arrays involves high hardware costs and great computational burden. This study proposes the concept fine-grid sparse pruned distributed parallel subarray (P-DPS) beamforming algorithm to achieve narrowband low complexity. Fine-grid refine traditional half-wavelength grids improve freedom optimization process reduce number active elements. However, grid refinement increases load conventional fast algorithms. To...

Existing water contaminant identification systems based on EEM (Emission–Emission Matrix) mostly focus the data level using a two-dimensional matrix, which makes it difficult to distinguish with similar location and shape owing insensitivity of matrix in contrast three-dimensional morphology. In this study, system was presented an innovative approach theory topology EEM-oriented Reeb graph proposed as new spectral feature. system, automatic scanning for designed constructed, relevant...

Total variation often yields staircase artifacts in the smooth region of image reconstruction. This paper proposes a hybrid high-order and fractional-order total with nonlocal regularization algorithm. The means is introduced to describe structural prior information. By selecting appropriate weights coefficients, proposed algorithm makes complement each other on It can solve problem non-smooth areas when enhance edges textures. In addition, it also addresses alleviates artifact produced by...

In recent years, ultraviolet–visible spectroscopy has been widely used for chemical oxygen demand (COD) measurements of water. However, compositions substance in different water samples can cause measurement deviations, so a local calibration is needed. this study, novel method proposed. The absorption spectra COD standard solutions and wastewater taken from four factories were collected. We analyzed the impact extracted morphology features their absorptive recognition models. Furthermore,...

The development of three-dimensional (3-D) underwater imaging systems is restricted by the high hardware costs associated with use a large number transducers, as well poor image quality due to degrading noise. This report presents design low-complexity 3-D system that can generate high-quality images. In particular, complex-weight sparse synthesis method for planar array presented reduce active elements. Then, denoising network referred an asymmetric-pyramid globe residual proposed enhance...

The content of chlorophyll-a is one the important indicators eutrophication in marine ranching. Accurate measurement great significance for sustainable development In order to realize insite detection ranching, a fluorometer based on lock-in amplifier was designed according fluorescence characteristics chlorophyll-a. A high-brightness 460nm LED used as excitation source and detected at 680nm by photodiode through an interference filter. At same time, reference light path compensate change...

Ultraviolet absorption spectroscopy is one of physical methods used for chemical oxygen demand (COD) measurements water. The absorbances in ultraviolet band have a relationship to COD. However, turbidity water could scatter emitting light and influence the absorbances. So it very important compensate impact turbidity. In this study, spectra standard COD solution (potassium acid phthalate), (Formazine) their mixture are sampled wavelength range from 220 750 nm. impacts measurement...

Waveguide display systems are widely used in various fields, especially head mounted display. Comparing with the traditional system, this device dramatically reduce size and mass. However, there still several fatal problems such as high scatting, cumbersome design chromatic aberration that should be solved. We designed fabricated a monochromatic portable eyewear system consist of comfortable waveguide two holographic gratings located on substrate symmetrically. record photopolymer medium...