Detection of Local Surface Defects in Metal Structures by the Method of Correlation Signal Processing

2014 ◽  
Vol 49 (5) ◽  
pp. 703-709 ◽  
Author(s):  
Ya. P. Kulynych ◽  
I. I. Tryhub
Keyword(s):  
Signal Processing ◽  
Surface Defects ◽  
Local Surface ◽  
Metal Structures ◽  
Correlation Signal Processing ◽  
Method Of Correlation

scholarly journals Межмодовый волоконный интерферометр на основе широкополосного источника света и анализатора оптического спектра для измерения внешних воздействий

2021 ◽  
Vol 47 (23) ◽  
pp. 8
Author(s):  
А.В. Петров ◽  
И.Е. Чапало ◽  
М.А. Бисярин ◽  
О.И. Котов
Keyword(s):  
Signal Processing ◽  
Light Source ◽  
Output Signal ◽  
Spectral Response ◽  
Spectral Signal ◽  
Broadband Light Source ◽  
Correlation Signal Processing ◽  
Scanning Range ◽  
Physical Quantities ◽  
Method Of Correlation

An intermodal fiber interferometer based on broadband light source and spectral signal processing is proposed and experimentally investigated. The influence of the parameters of the spectrum analyzer (scanning range and width of the instrumental spectral response function) on the output signal is demonstrated. It is shown that the method of correlation signal processing makes it possible to obtain linear and stable response to external fiber perturbations. The proposed interferometer scheme can be prospective for development of real-time sensors of physical quantities

Effective detection of metal surface defects based on double-line laser ultrasonic with convolutional neural networks

2021 ◽  
pp. 2150263
Author(s):  
Zixi Liu ◽  
Zhengliang Hu ◽  
Longxiang Wang ◽  
Tianshi Zhou ◽  
Jintao Chen ◽  
...  
Keyword(s):  
Signal Processing ◽  
Metal Surface ◽  
Surface Defects ◽  
Ultrasonic Signal ◽  
Classification Model ◽  
Frequency Resolution ◽  
Laser Ultrasonic ◽  
Double Line ◽  
Time Frequency ◽  
Defects Classification

The time–frequency analysis by smooth Pseudo-Wigner-Ville distribution (SPWVD) is utilized for the double-line laser ultrasonic signal processing, and the effective detection of the metal surface defect is achieved. The double-line source laser is adopted for achieving more defects information. The simulation model by using finite element method is established in a steel plate with three typical metal surface defects (i.e. crack, air hole and surface scratch) in detail. Besides, in order to improve the time resolution and frequency resolution of the signal, the SPWVD method is mainly used. In addition, the deep learning defect classification model based on VGG convolutional neural network (CNN) is set up, also, the data enhancement method is adopted to extend training data and improve the defects detection properties. The results show that, for different types of metal surface defects with sub-millimeter size, the classification accuracy of crack, air holes and scratch surface are 94.6%, 94% and 94.6%, respectively. The SPWVD and CNN algorithm for processing the laser ultrasonic signal and defects classification supplies a useful way to get the defect information, which is helpful for the ultrasonic signal processing and material evaluation.

SAR image enhancement via post-correlation signal processing

1984 ◽  
Vol GE-22 (6) ◽  
pp. 582-585
Author(s):  
Norman Dan Matthews ◽  
Verne H. Kaupp ◽  
William P. Waite ◽  
Harold C. Macdonald
Keyword(s):  
Signal Processing ◽  
Image Enhancement ◽  
Sar Image ◽  
Correlation Signal Processing

scholarly journals Способ компенсации интерференционного поля станционных радиопомех в коротковолновых широкополосных каналах радиосвязи

2020 ◽  
Author(s):  
I.M. Oroshchuk ◽  
M.V. Soloviev ◽  
A.N. Suchkov ◽  
A.A. Gavrilov
Keyword(s):  
Signal Processing ◽  
Spatial Correlation ◽  
Transfer Rate ◽  
Information Transfer ◽  
Narrow Band ◽  
Short Wave ◽  
Interference Field ◽  
Information Transfer Rate ◽  
Correlation Signal Processing ◽  
Correlation Properties

В работе представлены результаты экспериментальных исследований пространственно-корреляционных свойств узкополосных станционных помех коротковолнового диапазона. По результатам обработки экспериментальных данных получены обобщающие закономерности пространственно-корреляционных свойств интерференционного поля узкополосных станционных помех, определяющие возможность компенсации их влияния при обработке широкополосных сигналов в коротковолновых каналах радиосвязи, использующих цифровые антенные решетки с пространственно-корреляционной обработкой сигналов. С учетом возможностей компенсации интерференционного поля узкополосных станционных помех, исследована возможность повышения помехоустойчивости и скорости передачи информации в ионосферных каналах радиосвязи за счет передачи широкополосных сигналов с применением OFDM модуляции, более адаптируемой к условиям дисперсионных искажений и временного рассеяния сигналов, возникающих при распространении коротких волн. Результаты моделирования показали потенциальную возможность обеспечения повышенной скорости передачи информации в коротковолновых каналах с пространственно-корреляционной обработкой сигналов с заданной помехоустойчивостью при малых отношениях уровней сигнал/шум в точке приема, обеспечиваемой при меньших ограничениях выбора рабочей частоты, по сравнению с возможностями новых разработок скоростных коротковолновых модемов, в условиях ограниченности частотного ресурса коротковолнового диапазона из-за большой загруженности работой территориально-разнесенных станций.The experimental studies results of the spatial-correlation properties of narrow-band short-wave station interference are presents. Based on the results of processing the experimental data generalizing regularities of the interference field spatial-correlation properties of narrow-band station noise have been obtained. These regularities determine the possibility of compensating for their influence during processing broadband signals in radio channels using digital antenna arrays with spatial-correlation signal processing. Taking into account the possibilities of compensating for the interference field of narrow-band noise, the possibility of increasing the information transfer rate by transmitting wide-band signals using modulation with OFDM, which is more adaptable to the conditions of dispersion distortion and temporal dispersion of signals arising from the propagation of short waves in ionospheric communication channels, has been studied. The simulation results showed the potential for providing an increased information transfer rate in short-wave radio channels with spatial-correlation signal processing with a given noise immunity at low signal-to-noise levels at the receiving point, provided with less restrictions on the choice of operating frequency, compared with the capabilities of new developments of high-speed HF modems, in conditions of limited frequency resource of the HF band due to the heavy workload of geographically dispersed stations.

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