Roller bearings are some of the most critical and widely used components in rotating machinery. Appearance defect inspection plays a key role bearing quality control. However, real industries, defects usually extremely subtle have low probability occurrence. This leads to distribution discrepancies between number positive negative samples, which makes intelligent data-driven methods difficult develop deploy. paper presents small convolution neural network (SDD-CNN) for roller via an ensemble...

A method for extracting sea surface wind direction information from bistatic high-frequency (HF) radar Doppler spectra is presented. By analogy to the monostatic case, ratio of intensities positive and negative Bragg peaks used derive (ambiguous) direction. For operation, reference taken with respect scattering ellipse normal rather than beam The shown be valid based on simulated HF spectra. Wind also extracted data collected Southern China coast. Comparison between radar-measured directions...

Floating high-frequency surface-wave radar provides an effective solution to widening the range of detection by such systems. However, for radars with long coherence integration times, yaw angle variations during this period can have a significant impact on accuracy direction-of-arrival estimation. Although adaptive beamforming methods are applicable compensation, their effectiveness be significantly reduced when measured distortion antenna patterns is considered. To solve problem, iterative...

The high-frequency hybrid sky-surface wave radar (HF HSSWR) has recently been used to monitor large-area sea states. However, most of the HF HSSWR detection methods are based on assumption a no-tilt and constant height ionospheric model, influences caused by uneven electron density ignored. This paper proposes new surface current inversion scheme for distributed system, which considers unknown state as black box extracts key parameters compute scattering model. computational formula...

We consider estimating the direction-of-arrival (DOA) in presence of sensor array error. In proposed method, a blind signal separation joint approximation and diagonalization eigenmatrices algorithm, is implemented to separate vector mixing matrix consisting manifold error matrix. Based on new reconstruction output each individual signal, we propose novel DOA estimation calibration procedure. This method independent phase errors performs well against difference SNR signals. Numerical...

A new algorithm using array beamforming for estimating waves and currents from marine X-band radar image sequences is proposed. Array used to extract the wave directional spectrum sequences; intensity time series considered as signal received by "antennas" in conventional beamforming. To retrieve current velocity, following feature utilized: total power reaches a maximum when suitable calculation. Because based on individual pixel points, opposed full method, coordinate transformation...

In recent years, source camera identification has become a research hotspot in the field of image forensics and received increasing attention. It high application value combating spread pornographic photos, copyright authentication art tampering forensics, so on. Although existing algorithms greatly promote progress identification, they still cannot effectively reduce interference content with forensics. To suppress influence on multiscale content-independent feature fusion network (MCIFFN)...

Abstract A 57‐days record of surface currents observed from high‐frequency radars on the Chinese coast, along with wind records, are analyzed to investigate wintertime variability in southwestern Taiwan Strait. The M 2 tide dominates tidal variability, and semimajor axes semidiurnal current ellipses coincide well bathymetry contours suggesting interactions a propagating wave. However, phase progressions suggest that this wave undergoes an angular reflection near Bank (TWB). Diurnal less...

The spreading factor is considered as a key parameter that controls the concentration of directional distribution wave energy. It has been confirmed by many scholars there certain relationship between and sea surface wind. In application high frequency radar (HFSWR), extracted from ratio (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> ) power spectrum density (PSD) positive (P <sup xmlns:xlink="http://www.w3.org/1999/xlink">+</sup>...

Abstract Ionospheric nighttime enhancements are manifested in an increase of the electron density at nighttime. This paper studies latitudinal variation specific local time postmidnight enhancement peaks using ionosondes distributed low latitudes. To obtain parameters ionosphere, we manually extracted ionograms recorded by ionosondes. Cases show that there significant variations observed peaks. Results lower geomagnetic latitude, earlier peak occurred northern hemisphere. Additionally,...

Recently, high-frequency surface wave radar (HFSWR) has been widely applied in ocean dynamic parameter measurement. However, the echoes backscattered from tend to be contaminated by external radio frequency interference (RFI), and mitigation of RFI becomes an intractable problem, especially for wide beam HFSWR. The HFSWR measured data are multichannel. higher-order singular value decomposition (HOSVD) is effective method improve accuracy subspace estimation exploiting this multidimensional...

The conventional method of extracting ocean surface currents by high-frequency over-the-horizon radar is based on the fixed first-order Bragg frequency formula and ignores effects caused environment, especially in near-shore areas. In this letter, a current inversion model 2-D Fourier series expansion was developed. Doppler offset induced radial are dealt with bivariate functions group distance azimuth angle proposed method. By solving an overdetermined matrix equation least-square fitting...

One of the significant challenges in physical oceanography is getting an adequate space/time description ocean surface currents. possible solution maximum cross-correlation (MCC) method that we apply to hourly color images from Geostationary Ocean Color Imager (GOCI) over five years. Since GOCI provided a large number image pairs, introduce new MCC search strategy improve computational efficiency saving 95% processing time. We also use current merging increase total spatial coverage...

High-frequency surface wave radar (HF SWR) plays an important role in marine stereoscopic monitoring system. Nevertheless, the congestion of external radio frequency interference (RFI) HF band degrades its performance seriously. In this article, two novel fractional Fourier transform (FRFT)-based RFI suppression approaches are proposed. One is based on orthogonal projection sequences from domain, and other singular value decomposition (SVD) Hankel matrix inverse-Fourier domain. Simulation...

The multiple-input–multiple-output (MIMO) is a popular technology applied in the radar field for its ability to generate virtual elements, which ensures miniaturization case of obtaining large array aperture especially high-frequency surface wave radar. Antenna pattern distortions caused by environmental obstacles seriously contaminate manifold MIMO synthesized array, resulting inaccurate direction-of-arrival (DOA) estimation. In this letter, antenna patterns including transmitters and...

Abstract Large amount of real-time ocean currents measured by HF radar have been included into the observation database in many countries and regions, support applications for various marine activities such as research, Oil spill detection, tsunami warning, search rescue. However, due to performance inversion algorithms antennas, other reasons, there are differences credibility current results at different times locations, which brings on difficulties currents. This letter proposes a method...

A novel algorithm is developed to estimate the signal-to-noise ratio (SNR) for significant wave height (SWH) inversion of ocean fields imaged by X-band radar. The proposed utilizes geometric relationship linear dispersion relation gravity sea surface waves separate signal and noise without determination current. Compared with traditional SNR-based method, SWH derived using this method matches well that measured an in situ buoy nearby.

We explore the potential of computing coastal ocean surface currents from Moderate-Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Radiometer Suite (VIIRS) satellite imagery using maximum cross-correlation (MCC) method. To improve on past versions this method, we evaluate combining MODIS VIIRS thermal infrared (IR) color (OC) to map discuss benefits combination sensors optical channels. By these two sensors, total number vectors increases by 58.3 % . In addition, also make...

A novel technique to calibrate nonlinear array of HFSWR (HF surface wave radar) by exploiting single-DOA (direction arrival) sea echoes only is presented. It works online supply precise channel unmatching factors in real time without interrupting regular radar operating. The exhibits excellent robusticity and practicability when applied the OSMAR (ocean state monitoring analyzing system developed Wuhan University

Multi‐frequency high frequency surface wave radar (MHFSWR) shows good capability of anti‐interference, sea‐state information extraction and target detection. The authors develop a new technique to produce specified Doppler offset on the echoes spectra for each operating in simultaneous MHFSWR system. transmits modulated interrupted continuous signals with different linear phase offsets which are counted up from sweep cycle cycle. After being demodulated, frequencies same range can be...

HF radar in ocean remote sensing makes use of electromagnetic waves 10m to 100m wavelength from the rough sea surface measure current and wave parameter. Recently, a new time division multiple frequency system called OSMAR2009 has been developed by Wuhan University. One main advantage is that it great help extracting parameters signiflcant height. A further ability avoid interference. In addition, this technique ofiers opportunity shear. These advantages are gained transmitting chirp instead...

With the rapid development of information technology and widespread use Internet, QR codes are widely used in all walks life have a profound impact on people’s work life. However, code itself is likely to be printed forged, which will cause serious economic losses criminal offenses. Therefore, it great significance identify printer source code. A method identification for scanned Code image blocks based convolutional neural network (PSINet) proposed, innovatively introduces bottleneck...