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Three-dimensional holographic imaging using data collected over cylindrical apertures
摘要： The previously proposed near-field holographic imaging algorithms are based on the data collected over rectangular apertures. In this letter, we propose an approach for three-dimensional near-field holographic imaging with data collected over cylindrical apertures. Circular deconvolution is employed to deal with the periodicity of the functions along the azimuthal direction.
关键词： holography,microwave imaging,non-destructive testing
更新于2025-09-23 15:23:52
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Neural network-based hybrid signal processing approach for resolving thin marine protective coating by terahertz pulsed imaging
摘要： A novel approach was presented to enhance the capability of resolving thin coating layers using terahertz pulsed imaging (TPI) based on a neural network-based hybrid signal procession method, which is of great significance for in-line painting applications. In the present work, Terahertz detected signals were obtained by numerical simulation using finite difference time domain (FDTD) method. Models of marine protective coatings with different coating structures were calculated and analyzed. Different signal pre-processing techniques, including Fourier deconvolution, Fast Fourier Transform and wavelet analysis, were employed on the terahertz signals respectively to obtain various signal features. The processed signal was subsequently adopted as the input vectors for a neural network (NN). The optimization procedure for determining the architecture of neural network was investigated and the evaluated results obtained by the different networks were compared. Furthermore, the predicted results of thinner coating layer obtained by multiple-regression analysis method and BP network prediction method respectively were compared. The analysis demonstrated that the best prediction performance was achieved by neural network technique combined with wavelet analysis. Therefore, the hybrid signal processing approach could be recommended for terahertz non-destructive testing applications of marine protective coating.
关键词： Terahertz pulsed imaging,Non-destructive testing,Neural network,Thin marine protective coating
更新于2025-09-23 15:23:52
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AR aided Smart Sensing for In-line Condition Monitoring of IGBT Wafer
摘要： This paper describes an augmented reality (AR) aided smart sensing technique, for in-line condition monitoring of IGBT wafers. A series of signal processing algorithms are applied for enabling sensor intelligence. Based on electromagnetic infrared-visible-fusion (IVF), a supplementary palpable 3-D thermography layer is integrated with an IGBT wafer in real world environment. Before the IVF, independent component analysis (ICA) is implemented to identify defects in the wafer. The proposed AR aided smart sensing technique enhances user's perception and interaction between the industrial systems and the surrounding world. In contrast to conventional sensor techniques, it provides a non-destructive testing and evaluation (NDT&E) based high-throughput in-line condition monitoring method. The advantages of non-contact and time efficient of this smart sensing technique potentially bring huge benefit to yield management and production efficiency. AR aided smart sensing can improve the productivity, quality and reliability of power electronic materials and devices, as well as in other industrial applications.
关键词： Wafers,IGBT,Thermography,Non-destructive testing,Pulsed Eddy Current,Augmented Reality,Smart sensing
更新于2025-09-23 15:23:52
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Thickness identification of nonconductive coatings using terahertz time domain spectroscopy system
摘要： There are many nondestructive methods of coatings evaluation. Only a few of them can be utilized in case of coatings deposited on nonconductive elements. This paper presents application of a terahertz time domain spectroscopy for measuring thickness of thin nonconductive coatings. In order to develop a robust algorithm for thickness identification various experiments were carried out. A metal vessel filled with a small amount of oil was used as the test specimen. Such specimen allows us to easily achieve sample with a variable coating thickness.
关键词： terahertz,coatings,Non-destructive testing
更新于2025-09-23 15:23:52
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State-of-the art non-destructive techniques for defects detection in nanocomposites foam-core sandwich panels containing carbon nanotubes: IR thermography and microwave imaging
摘要： In this article, the state-of-the art of infrared (IR) thermography and microwave non-destructive (NDT) testing for inspection of defects in carbon nanotubes-based nanocomposite sandwich panels has been presented. Di?erent types of defects such as holes, notches and inclusion (Te?on) have been simulated in the polymeric foam-core of sandwich panels. The infrared (IR) thermography and microwave methods have been conducted to assess the simulated defects in the sandwich panel. The thermography results revealed that the thermal energy absorbance was higher in sandwich panel containing multi-walled carbon nanotubes (MWCNTs), however, various types of defects were well detected in both specimens with and without MWCNTs. From the result of microwave imaging, the same probability of NDT inspection was observed for detecting subsurface defects in sandwich panel and its nanocomposites. The use of low content of MWCNT (0.5 wt%) did not signi?cantly a?ect on the microwave absorption properties of sandwich panel among NDT procedure, however some changes of re?ection coe?cient amplitude in selected frequency bands were observable.
关键词： Multi-walled carbon nanotubes,Sandwich structures,Non-destructive testing,Nanocomposites
更新于2025-09-23 15:23:52
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[IEEE 2018 Wave Electronics and its Application in Information and Telecommunication Systems (WECONF) - Saint-Petersburg, Russia (2018.11.26-2018.11.30)] 2018 Wave Electronics and its Application in Information and Telecommunication Systems (WECONF) - Temperature Measurement Using Endoscopic Acousto-Optical Spectral Imaging System
摘要： The problem of measuring spatial temperature distribution over the surface of hard-to-reach objects with a non-uniform emissivity distribution is considered. We propose to solve it using acousto-optical spectral imaging system. This approach enables precise non-contact temperature measurements as well as contrast visualization in arbitrary narrow spectral bands. The temperature measurement of filament lamp using rigid borescope and acousto-optic imaging filter is presented.
关键词： endoscopy,non-destructive testing,spectral imaging,temperature measurement,acousto-optical tunable filter
更新于2025-09-23 15:22:29
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Predicting Mechanical Strength of In-Use Firefighter Protective Clothing Using Near-Infrared Spectroscopy
摘要： The exact lifespan of in-use firefighter protective clothing is difficult to predict due to the large variations in use between individual garments. Furthermore, testing methods used to evaluate new protective clothing are destructive in nature and could not be applied to in-use garments. Various non-destructive techniques have been proposed for the evaluation of in-use clothing, each possessing its own advantages and disadvantages. The ability of near-infrared spectroscopy to predict the tensile strength of thermally aged fabrics used in protective clothing for wildland firefighters and other workers is investigated here. Fabrics were exposed to heat fluxes from 10 kW/m2 to 40 kW/m2 for various durations using the cone calorimeter, after which the tensile strength of the fabrics was measured. Temperatures measured during the exposures and results of thermal gravimetric analysis tests were used to interpret changes in tensile strength. Multivariate linear regression was used to develop correlations between the tensile strength and the reflectance values measured between 1500 nm and 2500 nm for new and thermally aged fabrics. It was found that models based on reflectance measurements made at as few as three wavelengths could be used to estimate the tensile strength of the thermally aged specimens.
关键词： Thermal ageing,Near-infrared spectroscopy,Firefighter,Durability,Non-destructive testing,Protective clothing
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Ultrasonics Symposium (IUS) - Kobe, Japan (2018.10.22-2018.10.25)] 2018 IEEE International Ultrasonics Symposium (IUS) - High Frequency Optical Probe for BAW/SAW Devices
摘要： Optical properties of semiconductor devices for LED and OLED devices. We present a novel optical tool based on heterodyne interferometry that is capable of detecting surface and subsurface defects in semiconductor materials with high precision. The tool operates at frequencies up to 25 GHz and can achieve a detection limit of less than 1 nm. This method is particularly useful for quality control in the optoelectronics industry, as it allows for non-destructive testing of devices such as LEDs and OLEDs. Our results demonstrate that this tool can effectively identify defects that are not detectable with conventional optical microscopy.
关键词： non-destructive testing,defect detection,optoelectronics,semiconductor devices,LED,OLED,heterodyne interferometry
更新于2025-09-23 15:22:29
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A novel computational supplement to an IR-thermography based non-destructive test of electrofusion polyethylene joints
摘要： Electrofusion Polyethylene (PE) joints are important elements of the gas distribution networks. Unfortunately they are prone to leakage if not tested thoroughly. Our team has recently proposed a novel noncontact and IR thermal non-destructive test for these PE joints. That is, to induce a controlled heat pulse within the joint via its internal wire, and compare its thermal response with other experimental reference cases. Two gaps exist in this method due to the lack of access to a mathematical model. Firstly the pulsing duration at different initial temperatures are only determined by trial and errors. Secondly, preparing experimental reference thermal images at different joint conditions is considerably costly. Therefore, here we rigorously simulate this pulsing process to tackle both abovementioned shortcomings. We experimentally validate our simulation and report the appropriate pulsing durations between 300 K and 320 K initial temperatures. Moreover, we successfully screen a contaminated joint nondestructively.
关键词： Non destructive testing,Dynamic heat transfer,Non-contact IR test,Electrofusion polyethylene joint,IR thermal imaging
更新于2025-09-23 15:21:01
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Determination of Thermal Diffusivity of Basalt Fiber Reinforced Epoxy Composite using Infrared Thermography
摘要： In recent years, there is a great demand for ecofriendly, light weight and cost effective composites. Basalt fiber is one such naturally available fiber which offers exceptional properties over glass fibers. In this study a Basalt fiber reinforced composites were fabricated by vacuum bagging technique. Thermal properties of these composites were determined using infrared thermography. In-depth and in-plane thermal diffusivity are determined by using pulse thermography and space resolve method respectively. The in-plane thermal diffusivity was determined in the transmission and reflection modes. In-depth thermal diffusivity is validated using a Light flash method.
关键词： Infrared thermography,Non-Destructive Testing,thermal diffusivity,Basalt fiber reinforced composites,space resolved method
更新于2025-09-23 15:21:01