High-Resolution Millimeter-Wave Tomography System for Nondestructive Testing of Low-Permittivity Materials

Och, Andreas; Hölzl, Patrick A.; Schuster, Stefan; Scheiblhofer, Stefan; Zankl, Dominik; Pathuri-Bhuvana, Venkata; Weigel, Robert

doi:10.1109/tmtt.2020.3030662

Cited by 23 publications

(11 citation statements)

References 31 publications

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“…In the measurement setup, two frequency modulated continuous wave (FMCW) radar modules are placed on opposite sides of a circular RoI with 50 cm diameter as shown in Fig. 12 [8]. Each of the FMCW radar module has 1 Tx and 2 Rx antennas which can transmit and receive mmWave signals in the frequency range of 76 − 81 GHz.…”

Section: Tomographic Reconstruction Of Materials Permittivity Inside ...mentioning

confidence: 99%

“…Time-of-flight (ToF) tomography is a well known noninvasive imaging technique used in several industrial [1]- [3], medical [4]- [6], manufacturing [7] and testing [8], [9] applications [10]. In general, the materials/features in a regionof-interest (RoI) can alter the speed of electromagnetic or mechanical signals traveling through the RoI.…”

Section: Introductionmentioning

confidence: 99%

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Joint Calibration and Tomographic Reconstruction for Time-of-Flight Sensor Systems

bhuvana¹,

Och²,

Schuster³

2022

Preprint

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<p>A typical time-of-flight (ToF) tomography method requires accurate information about the system’s calibration parameters in order to reconstruct the features of interest within a region of interest (RoI). This paper proposes a constrained joint calibration and tomography (CJCT) method based on a separable least squares (SLS) approach for ToF tomographic systems. Contrary to the existing offline and online calibration methods, the proposed method utilizes prior information about the calibration parameters in the form of constraints. The imposed constraints allow for an efficient search for the minimum of the inherent SLS cost function by reducing the system and measurement ambiguities. Thus, the proposed CJCT method can find the optimum values for both tomography and calibration parameters more efficiently compared to unconstrained methods. The general applicability of the proposed method is demonstrated by evaluating it on two applications: tomographic reconstruction of the permittivity distribution in a RoI using ToF measurements from a high resolution millimeter-wave radar system, and the temperature distribution inside an industrial blast furnace using measured and simulated acoustic ToF values. The simulation and experimental results show that the proposed method performs significantly better in terms of tomographic reconstruction accuracy compared to unconstrained methods.</p>

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Section: Tomographic Reconstruction Of Materials Permittivity Inside ...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Joint Calibration and Tomographic Reconstruction for Time-of-Flight Sensor Systems

bhuvana¹,

Och²,

Schuster³

2022

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…In the food industry, MWT has been widely applied for inspection and quality control [ 31 , 32 , 33 ]. Sensing of low permittivity materials, such as gaseous substances or foam with high air content, with MWT is reported in [ 34 ]. Moreover, the authors have reported their contribution in [ 9 , 35 , 36 , 37 ] for the present application of MWT in estimating the moisture content in polymer foam.…”

Section: Related Workmentioning

confidence: 99%

Supporting Visualization Analysis in Industrial Process Tomography by Using Augmented Reality—A Case Study of an Industrial Microwave Drying System

Zhang

Omrani

Yadav

et al. 2021

Sensors

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Industrial process tomography (IPT) based process control is an advisable approach in industrial heating processes for improving system efficiency and quality. When using it, appropriate dataflow pipelines and visualizations are key for domain users to implement precise data acquisition and analysis. In this article, we propose a complete data processing and visualizing workflow regarding a specific case—microwave tomography (MWT) controlled industrial microwave drying system. Furthermore, we present the up-to-date augmented reality (AR) technique to support the corresponding data visualization and on-site analysis. As a pioneering study of using AR to benefit IPT systems, the proposed AR module provides straightforward and comprehensible visualizations pertaining to the process data to the related users. Inside the dataflow of the case, a time reversal imaging algorithm, a post-imaging segmentation, and a volumetric visualization module are included. For the time reversal algorithm, we exhaustively introduce each step for MWT image reconstruction and then present the simulated results. For the post-imaging segmentation, an automatic tomographic segmentation algorithm is utilized to reveal the significant information contained in the reconstructed images. For volumetric visualization, the 3D generated information is displayed. Finally, the proposed AR system is integrated with the on-going process data, including reconstructed, segmented, and volumetric images, which are used for facilitating interactive on-site data analysis for domain users. The central part of the AR system is implemented by a mobile app that is currently supported on iOS/Android platforms.

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“…❖ Diagnostics of composite materials in aerospace and other industries [26], [27], [28], [29], [30], [31], [32], [33], [34] ❖ Diagnostics of building details and constructions including cultural heritage monuments [35], [36], [37], [38], [39] ❖ Archaeological and paleontological imaging [40], [41], [42] ❖ Landmine detection and discrimination [9], [10], [11], [43], [44], [45], [46] ❖ Security systems [47], [48], [49], [50], [51], [52], [53] ❖ Detection of wood-boring insect damage [54] ❖ Medical imaging [55], [56], [57], [58], [59].…”

Section: Hsr Hologramsmentioning

confidence: 99%

Design and Applications of Multi-Frequency Holographic Subsurface Radar: Review and Case Histories

Ivashov¹,

Capineri²,

Bechtel³

et al. 2021

Preprint

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Holographic subsurface radar (HSR) is currently not in widespread usage. This is due to an historical perspective in the ground penetrating radar (GPR) community that the high attenuation of electromagnetic waves in most media of interest, and the inability to apply time-varying gain to the continuous wave (CW) HSR signal precludes sufficient effective penetration depth. While it is true that the fundamental physics of HSR, with its use of a CW signal, does not allow amplification of later (i.e. deeper) arrivals in lossy media (as is possible with impulse subsurface radar — ISR), HSR has distinct some distinctive advantages. The most important of these is the ability to do shallow subsurface imaging with a resolution that is not possible with ISR. In addition, the design of an HSR system is simpler than for ISR due to the relatively low-tech transmitting and receiving antennae. This paper provides a review of the main principles of HSR through an optical analogy and describes possible algorithms for radar hologram reconstruction. We also present a review of the history of development of systems and applications for HSR of the “RASCAN” type which is possibly the only holographic subsurface radar that is produced in lots. Among the subsurface imaging and remote sensing applications considered are humanitarian demining, construction inspection, surveys of historic architecture and artworks, nondestructive testing of dielectric aerospace materials, security applications, paleontology, detection of wood-boring insect damage, and others. Each application is illustrated with relevant data acquired in laboratory and/or field experiments.

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High-Resolution Millimeter-Wave Tomography System for Nondestructive Testing of Low-Permittivity Materials

Cited by 23 publications

References 31 publications

Joint Calibration and Tomographic Reconstruction for Time-of-Flight Sensor Systems

Joint Calibration and Tomographic Reconstruction for Time-of-Flight Sensor Systems

Supporting Visualization Analysis in Industrial Process Tomography by Using Augmented Reality—A Case Study of an Industrial Microwave Drying System

Design and Applications of Multi-Frequency Holographic Subsurface Radar: Review and Case Histories

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