Defects investigation in thermal insulation coatings with microwave imaging based on a 22 GHz holographic radar

Chizh, Margarita; Zhuravlev, Andrey; Razevig, Vladimir; Ivashov, Sergey; Falorni, Pierluigi; Capineri, Lorenzo

doi:10.1016/j.ndteint.2019.102191

Cited by 14 publications

(10 citation statements)

References 10 publications

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“…Various NDT methods are used to examine cultural objects, such as X-ray [1] and ultrasound [2] technologies, infrared thermography [3], terahertz spectroscopy [4], as well as subsurface radars of both impulse [5] and holographic [6] types. The last devices have been used in recent years to obtain images of the internal structure of objects and detect hidden defects, such as delamination, chipping, surface and subsurface cracks, reinforcement corrosion, the presence of small air voids, and moisture distribution [7,8]. All these listed methods are characterized by different spatial resolution and penetration depth, as well as different sensitivity to changes in the physical properties of materials.…”

Section: Introductionmentioning

confidence: 99%

An Example of Microwave Holography Investigation of an Old Orthodox Russian Icon Dated to 19th Century

Ivashov

Razevig

Sergeev³

et al. 2022

Heritage

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The study, preservation and restoration of the cultural heritage objects of mankind are not only of great cultural importance but also have a significant economic component because cultural values of past centuries attract tourists from all over the world. The use of modern technical and scientific achievements in the field of non-destructive testing makes it possible to obtain new knowledge about cultural objects regarding their origin and dating, as well as to contribute to their better restoration and preservation. An important component of their use is additional opportunities to identify high quality fakes of original cultural objects that have historical significance. The capabilities of various non-destructive testing (NDT) methods used to examine cultural objects are characterized by their penetration depth, resolution, and sensitivity to material properties. Thus, in many cases, it is necessary to perform multi-sensor non-destructive testing and creating large data sets that require an efficient evaluation. This article considers an example of using microwave (MW) holographic sensors for the examining of an old Orthodox Russian Icon dated of the late 19th century. The paper describes the technology of microwave holography, which has recently been applied to the examination of art works. Unlike the well-studied X-ray method, MW holography makes it possible to examine objects with one-sided access. Its other advantages are the relative cheapness of the equipment and the safety of use due to the low level of radiation. The article describes a MW holograms reconstruction algorithm, as well as a method for improving the quality of obtained MW images. The data collected at MW research of the Icon are compared with the results of X-ray examination and confirmed by subsequent opening and visual examination performed by professional restorers.

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Section: Introductionmentioning

confidence: 99%

An Example of Microwave Holography Investigation of an Old Orthodox Russian Icon Dated to 19th Century

Ivashov

Razevig

Sergeev³

et al. 2022

Heritage

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show abstract

“…crack detection including coaxial probes, open-ended waveguides, and time-reversal techniques. Extensive published works have focused on crack detection, crack sizing, and crack imaging [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Although these technologies are easy to implement, they all require accurate measuring of signal properties including frequency, amplitude, and phase.…”

Section: Introductionmentioning

confidence: 99%

Simplistic, Efficient, and Low-Cost Crack Detection of Dielectric Materials Based on Millimeter-Wave Interference

Chen

Yin

et al. 2022

Electronics

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This paper proposes a simplistic, efficient, and low-cost method of millimeter-wave nondestructive testing (NDT) of dielectric material cracks based on millimeter-wave interference. A relationship between combining efficiency, phase difference, and amplitude difference was analyzed. We found that phase difference was the main factor that affects combining efficiency. A change in combining efficiency of more than 1% was caused by a phase-difference altering of greater than 1.2° in a specific range. A relevant model was simulated with CST, and the operating frequency and antenna spacing were optimized to enhance sensitivity of the measuring system. Then, a Ka-band NDT system was built to test the combining efficiencies of different cracks. The experimental results showed that for polytetrafluoroethylene (PTFE) plates with a thickness of 5 mm, cracks with a width of about 0.4 mm, which is about 0.07 λg, could be detected at 35 GHz. Experimental results, simulation results, and theoretical derivation are basically consistent. Large-scale online applications of this NDT method in various industries appear feasible due to the above characteristics.

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“…Radio vision technology allows using radio waves scattered by objects to determine their position and shape, including when the objects are in an optically opaque environment, but relatively transparent in the radio range. This technology has various applications, such as: nondestructive inspection of structures and materials [1][2][3][4]; detection of prohibited items concealed under human clothing [5,6]; visualization of internal structure of human tissues and organs in medicine [7,8]; detection of people behind obstacles [9]. Characteristics of objects are determined by the so-called radar images (radio images), the process of obtaining which consists in the registration of a complex radio hologram of the object and its subsequent recovery.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Back-Scattering and Forward-Scattering Methods in Short Range Microwave Imaging Systems

2022

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Microwave imaging technique allows obtaining images of hidden objects in structures and media using microwaves. Usually in short-range microwave imaging systems, the back-scattered signal is used, when a combined transmit-receive antenna scans over a plane, forming a two-dimensional synthesized aperture, while the signal reflected from the object of observation is recorded, as a result of which a microwave hologram of the object is formed. The second option involves registering the forward-scattered signal, when the transmitting and receiving antennas are located on opposite sides of the object and scan synchronously. The purpose of this work is a theoretical and experimental comparison of these two sounding options, identifying the advantages and disadvantages of each option, taking into account the features that arise when solving various problems of microwave imaging. Keywords: microwave holography, mivrowave image, back-scattered signal, forward-scattered signal, range resolution.

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Defects investigation in thermal insulation coatings with microwave imaging based on a 22 GHz holographic radar

Cited by 14 publications

References 10 publications

An Example of Microwave Holography Investigation of an Old Orthodox Russian Icon Dated to 19th Century

An Example of Microwave Holography Investigation of an Old Orthodox Russian Icon Dated to 19th Century

Simplistic, Efficient, and Low-Cost Crack Detection of Dielectric Materials Based on Millimeter-Wave Interference

Comparison of Back-Scattering and Forward-Scattering Methods in Short Range Microwave Imaging Systems

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Defects investigation in thermal insulation coatings with microwave imaging based on a 22 GHz holographic radar

Cited by 14 publications

References 10 publications

An Example of Microwave Holography Investigation of an Old Orthodox Russian Icon Dated to 19th Century

An Example of Microwave Holography Investigation of an Old Orthodox Russian Icon Dated to 19th Century

Simplistic, Efficient, and Low-Cost Crack Detection of Dielectric Materials Based on Millimeter-Wave Interference

Comparison of Back-Scattering and Forward-Scattering Methods in Short Range Microwave Imaging Systems

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Defects investigation in thermal insulation coatings with microwave imaging based on a 22 GHz holographic radar