Articles | Volume 7, issue 1
https://doi.org/10.5194/jsss-7-309-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue:
https://doi.org/10.5194/jsss-7-309-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Regular research article
| 
20 Apr 2018
Regular research article |
| 20 Apr 2018
| 20 Apr 2018
Non-destructive testing of arbitrarily shaped refractive objects with millimetre-wave synthetic aperture radar imaging
Ingrid Ullmann
CORRESPONDING AUTHOR
Institute of Microwaves and Photonics, Friedrich-Alexander University, Erlangen, 91058, Germany
Julian Adametz
Institute of Microwaves and Photonics, Friedrich-Alexander University, Erlangen, 91058, Germany
Daniel Oppelt
Institute of Microwaves and Photonics, Friedrich-Alexander University, Erlangen, 91058, Germany
Andreas Benedikter
Institute of Microwaves and Photonics, Friedrich-Alexander University, Erlangen, 91058, Germany
Martin Vossiek
Institute of Microwaves and Photonics, Friedrich-Alexander University, Erlangen, 91058, Germany
Related subject area
Measurement systems: Sensor signal processing and electronics
Extraction of nanometer-scale displacements from noisy signals at frequencies down to 1 mHz obtained by differential laser Doppler vibrometry
Simple in-system control of microphone sensitivities in an array
Wireless surface acoustic wave resonator sensors: fast Fourier transform, empirical mode decomposition or wavelets for the frequency estimation in one shot?
Ultrasonic measurement setup for monitoring pre-thawing stages of food
Digital twin concepts for linking live sensor data with real-time models
Assisting the automated analysis of chemical–analytical measurements in spirits using validated algorithms and an intuitive user interface
Simulation-based investigation of the metrological interface structural resolution capability of X-ray computed tomography scanners
Design of a CMOS memristor emulator-based, self-adaptive spiking analog-to-digital data conversion as the lowest level of a self-x hierarchy
Smart in-cylinder pressure sensor for closed-loop combustion control
Efficient transient testing procedure using a novel experience replay particle swarm optimizer for THD-based robust design and optimization of self-X sensory electronics in industry 4.0
Intelligent fault detection of electrical assemblies using hierarchical convolutional networks for supporting automatic optical inspection systems
Measurement uncertainty analysis of field-programmable gate-array-based, real-time signal processing for ultrasound flow imaging
Compilation of training datasets for use of convolutional neural networks supporting automatic inspection processes in industry 4.0 based electronic manufacturing
Employing correlation for wireless components and device characterization in reverberation chambers
Impedance model for a high-temperature ceramic humidity sensor
Determining the dimension of subsurface defects by active infrared thermography – experimental research
Inverse calculation of strain profiles from ETDR measurements using artificial neural networks
An ultra-low noise capacitance to voltage converter for sensor applications in 0.35 µm CMOS
Development of a non-contact torque transducer based on the laser speckle contrast method
Development of a chopper charge amplifier for measuring the cavity pressure inside injection moulding tools and signal optimisation with a Kalman filter
Optimized mixed-domain signal synthesis for broadband impedance spectroscopy measurements on lithium ion cells for automotive applications
High-accuracy current measurement with low-cost shunts by means of dynamic error correction
A compact readout platform for spectral-optical sensors
High-speed camera-based measurement system for aeroacoustic investigations
Shutter-less calibration of uncooled infrared cameras
A novel approach for detecting HMDSO poisoning of metal oxide gas sensors and improving their stability by temperature cycled operation
Micro- and nanocoordinate measurements of micro-parts with 3-D tunnelling current probing
An electrical characterisation system for the real-time acquisition of multiple independent sensing parameters from organic thin film transistors
Piezoelectric transceiver matching for multiple frequencies
Metal oxide semiconductor gas sensor self-test using Fourier-based impedance spectroscopy
Work area monitoring in dynamic environments using multiple auto-aligning 3-D sensors
Principal component analysis for fast and automated thermographic inspection of internal structures in sandwich parts
Near-field interrogation of SAW resonators on rotating machinery
Magnetic properties of CHAMP and their effects on in-orbit calibration
Dhyan Kohlmann, Marvin Schewe, Hendrik Wulfmeier, Christian Rembe, and Holger Fritze
J. Sens. Sens. Syst., 13, 167–177, https://doi.org/10.5194/jsss-13-167-2024, https://doi.org/10.5194/jsss-13-167-2024, 2024
Short summary
Short summary
A very small, anharmonic but periodic signal is separated from a noise background that is orders of magnitude larger than the pure signal. The approach consists of a sequence of filters and transformations and is demonstrated on an interferometric measurement of the high-temperature chemical expansion of a thin film, containing heat haze, thermal length drift, and parasitic vibrations. The displacement is 38 % larger and the uncertainty 35 % lower than when evaluated with previous approaches.
Artem Ivanov
J. Sens. Sens. Syst., 13, 81–88, https://doi.org/10.5194/jsss-13-81-2024, https://doi.org/10.5194/jsss-13-81-2024, 2024
Short summary
Short summary
The presented approach allows users to perform measurements of microphone responses directly in the array using the internal hardware and so to characterize the whole signal chain of microphone–preamplifier–ADC. The measurements do not need special equipment and can be carried out in ordinary reverberant locations. A loudspeaker driven by a voltage pulse is used to produce a sound wave with a short first wavefront. Processing only this wavefront suppresses reflected waves that arrive later.
Angel Scipioni, Pascal Rischette, and Agnès Santori
J. Sens. Sens. Syst., 12, 247–260, https://doi.org/10.5194/jsss-12-247-2023, https://doi.org/10.5194/jsss-12-247-2023, 2023
Short summary
Short summary
Many applications which measure physical quantities rely on wireless surface acoustic wave sensors. The accuracy of this sensor depends directly on the measurement of its main frequency. This paper aims to compare three methods for this measurement in one shot: fast Fourier transform, discrete wavelet transform, and empirical mode decomposition. Results show that the choice of the method is conditioned by the disturbance level and that the wavelet method is the best way for harsh environments.
Ruchi Jha, Walter Lang, and Reiner Jedermann
J. Sens. Sens. Syst., 12, 133–139, https://doi.org/10.5194/jsss-12-133-2023, https://doi.org/10.5194/jsss-12-133-2023, 2023
Short summary
Short summary
In order to save time and avoid overheating of food during unfreezing, the study of ice content can be very useful. The aim of the research is to design an ultrasound-based sensor system that is able to comment on the content of ice in the sample food product. Some sample food products are tested, and the observations and challenges concerning the same are mentioned in the research paper.
Reiner Jedermann, Kunal Singh, Walter Lang, and Pramod Mahajan
J. Sens. Sens. Syst., 12, 111–121, https://doi.org/10.5194/jsss-12-111-2023, https://doi.org/10.5194/jsss-12-111-2023, 2023
Short summary
Short summary
Mathematical models are often required to process sensor data in a digital twin platform. The translation of models to an updateable format enables predicting hidden states of the physical object, which are not directly measurable. The linking of different models is demonstrated by data from field tests on fruit transportation in refrigerated containers. We programmed a streaming platform that enables easy integration of such updatable models with only a few milliseconds of processing overhead.
Andreas T. Grasskamp, Satnam Singh, Helen Haug, and Tilman Sauerwald
J. Sens. Sens. Syst., 12, 93–101, https://doi.org/10.5194/jsss-12-93-2023, https://doi.org/10.5194/jsss-12-93-2023, 2023
Short summary
Short summary
In this work, we have developed and validated a semi-automatic approach that greatly reduces the amount of interaction and effort needed for analyzing samples via gas chromatography–mass spectrometry. Further, unlike many other approaches, our developed tool is accessible to the novice and does not require any programming experience. Using whisky as an example substance, we show how the analysis method compares to conventional software, and we validate our approach against that.
Matthias Busch and Tino Hausotte
J. Sens. Sens. Syst., 12, 1–8, https://doi.org/10.5194/jsss-12-1-2023, https://doi.org/10.5194/jsss-12-1-2023, 2023
Short summary
Short summary
The paper presents a specimen and evaluation method for interface structural resolution testing of X-ray computed tomography systems based on CT simulations. The geometry is oriented to the norms of image quality investigation. The evaluation is based on profile lines of the cross-sectional images that pass through the boreholes. All statements on resolution refer to the entire measurement chain and, thus, in addition to the reconstruction algorithm also to the surface determination method used.
Hamam Abd and Andreas König
J. Sens. Sens. Syst., 11, 233–262, https://doi.org/10.5194/jsss-11-233-2022, https://doi.org/10.5194/jsss-11-233-2022, 2022
Short summary
Short summary
We pursue a promising novel self-adaptive spiking neural analog-to-digital data conversion (SN-ADC) design that uses spike time to carry information. Thus, SN-ADC can be effectively translated to aggressive new technologies to implement reliable advanced sensory electronic systems. The SN-ADC supports self-x (self-calibration, self-optimization, and self-healing) and machine learning required for the internet of things and Industry 4.0 and is based on a self-adaptive CMOS memristor.
Dennis Vollberg, Peter Gibson, Günter Schultes, Hans-Werner Groh, and Thomas Heinze
J. Sens. Sens. Syst., 11, 1–13, https://doi.org/10.5194/jsss-11-1-2022, https://doi.org/10.5194/jsss-11-1-2022, 2022
Short summary
Short summary
We developed a smart in-cylinder pressure sensor for closed-loop combustion control. The sensor concept is based on a robust and reliable steel membrane equipped with highly strain-sensitive and temperature-stable thin films. The sensor system is complemented by a smart electronics allowing real-time data processing for calculation of different combustion parameters. The data are utilized to control the igniting timing of a spark plug for efficient operation of a combustion engine.
Qummar Zaman, Senan Alraho, and Andreas König
J. Sens. Sens. Syst., 10, 193–206, https://doi.org/10.5194/jsss-10-193-2021, https://doi.org/10.5194/jsss-10-193-2021, 2021
Short summary
Short summary
A novel experience replay particle swarm optimization algorithm is presented and successfully deployed to improve the optimization performance for reconfigurable analog integrated circuits of industry 4.0. An optimization approach is introduced that relied on THD-based indirect measurement method that varies from the traditional calibration approach. Instead, the proposed calibration methodology optimizes all characteristics of the reconfigurable amplifier at once.
Alida Ilse Maria Schwebig and Rainer Tutsch
J. Sens. Sens. Syst., 9, 363–374, https://doi.org/10.5194/jsss-9-363-2020, https://doi.org/10.5194/jsss-9-363-2020, 2020
Short summary
Short summary
In order to further increase the performance of neural networks in the field of optical quality assurance of soldered joints, a hierarchical classifier can be used instead of a single network. The global expansion of the classifier enables the inspection task to be distributed over several subnetworks, which results in higher accuracy. Since the individual sub-models only concentrate on the identification of certain characteristics, categorical problems can be solved more effectively.
Richard Nauber, Lars Büttner, and Jürgen Czarske
J. Sens. Sens. Syst., 9, 227–238, https://doi.org/10.5194/jsss-9-227-2020, https://doi.org/10.5194/jsss-9-227-2020, 2020
Short summary
Short summary
To improve the energy efficiency of industrial processes, such as continuous steel casting, lab-scale experiments with liquid metals are performed. We present an ultrasound Doppler signal process for multiplane, high-frame-rate flow imaging. We achieve real-time operations with an efficient implementation in a field-programmable gate array (FPGA). We analyze the contributions to the uncertainty of the velocity measurement and relate it to its fundamental limit.
Alida Ilse Maria Schwebig and Rainer Tutsch
J. Sens. Sens. Syst., 9, 167–178, https://doi.org/10.5194/jsss-9-167-2020, https://doi.org/10.5194/jsss-9-167-2020, 2020
Short summary
Short summary
This article presents a classification concept based on deep learning as an additional optical test method for real-time visualization and analysis of electrical assemblies in the production environment. For this purpose, a neural convolutional network is used to identify the quality of the solder joint of surface-mounted chip components in the inspection images. The concept can be used to increase the detection performance of the solder joint inspection systems.
Christoph Cammin, Dmytro Krush, Ralf Heynicke, and Gerd Scholl
J. Sens. Sens. Syst., 8, 185–194, https://doi.org/10.5194/jsss-8-185-2019, https://doi.org/10.5194/jsss-8-185-2019, 2019
Short summary
Short summary
Reverberation chambers are well-proven test environments for RF measurements. Typically, mean values are taken from the measurements to characterize the equipment under test. In the novel approach presented in this paper, the correlation of measured sample sequences is utilized to detect deviations, in particular of the radiation characteristics, from reference equipment.
Henrik Lensch, Manuel Bastuck, Tobias Baur, Andreas Schütze, and Tilman Sauerwald
J. Sens. Sens. Syst., 8, 161–169, https://doi.org/10.5194/jsss-8-161-2019, https://doi.org/10.5194/jsss-8-161-2019, 2019
Short summary
Short summary
The measurement of humidity in industrial applications is still an important research issue. Especially under rough operation conditions the current humidity sensor comes to its limitations. To this end, we are developing an integrated sensor system using a metal oxide sensor with impedance spectroscopy as multi-signal generation allowing the discrimination of humidity and reducing gases. The submitted paper focuses on the modeling of the humidity-dependent aspects of impedance.
Slawomir Grys
J. Sens. Sens. Syst., 7, 153–160, https://doi.org/10.5194/jsss-7-153-2018, https://doi.org/10.5194/jsss-7-153-2018, 2018
Robin Höhne, Pawel Kostka, and Niels Modler
J. Sens. Sens. Syst., 6, 389–394, https://doi.org/10.5194/jsss-6-389-2017, https://doi.org/10.5194/jsss-6-389-2017, 2017
Short summary
Short summary
This paper focuses on a novel carbon fibre sensor technology that exploits the low-cost and low-energy electrical reflectometry method for a spatially resolved strain measurement. The application of artificial neural networks for mapping the measured electrical signal to the existing strain profile is demonstrated. The potential and current limits are highlighted. The sensor is a promising part for the next generation of light-weight structures with operando health monitoring systems.
Alexander Utz, Christian Walk, Norbert Haas, Tatjana Fedtschenko, Alexander Stanitzki, Mir Mokhtari, Michael Görtz, Michael Kraft, and Rainer Kokozinski
J. Sens. Sens. Syst., 6, 285–301, https://doi.org/10.5194/jsss-6-285-2017, https://doi.org/10.5194/jsss-6-285-2017, 2017
Alberto Garinei and Roberto Marsili
J. Sens. Sens. Syst., 6, 253–258, https://doi.org/10.5194/jsss-6-253-2017, https://doi.org/10.5194/jsss-6-253-2017, 2017
Short summary
Short summary
When a torque measurement is required, torque transducers show many drawbacks during their use: the usual limits are the need for contact and the effects on shaft line parameters. A new approach is proposed in this work: a non-contact torque meter for a machine shaft has been developed, based on a laser speckle contrast method. It carries out torque measurements evaluating the torsional displacement between two distinct sections of the shaft, through the monitoring of their roughness.
Manuel Schneider, Alexander Jahn, Norbert Greifzu, and Norbert Fränzel
J. Sens. Sens. Syst., 6, 199–210, https://doi.org/10.5194/jsss-6-199-2017, https://doi.org/10.5194/jsss-6-199-2017, 2017
Short summary
Short summary
This article describes a chopper amplifier which has been specially developed for piezoelectric pressure sensors. It is shown that the amplifier provides good results for pressure measurement in injection moulds. A special feature of this work is the signal optimisation through the use of a Kalman filter.
Peter Haußmann and Joachim Melbert
J. Sens. Sens. Syst., 6, 65–76, https://doi.org/10.5194/jsss-6-65-2017, https://doi.org/10.5194/jsss-6-65-2017, 2017
Short summary
Short summary
A method to generate broadband waveforms with low peak-to-peak amplitude based on distinct frequency domain profiles is presented, which includes random phase variation and numerical optimization. The peak-to-peak amplitude can be reduced by 71 % compared to zero-phase pulses with equal frequency domain characteristics. Used as excitation signals for impedance spectroscopy, the waveforms yield good results at significantly reduced measurement duration compared to established measurement methods.
Patrick Weßkamp and Joachim Melbert
J. Sens. Sens. Syst., 5, 389–400, https://doi.org/10.5194/jsss-5-389-2016, https://doi.org/10.5194/jsss-5-389-2016, 2016
Short summary
Short summary
Measurement of electrical current is important for many scientific and industrial applications. Often shunt resistors are used. However, thermal effects due to self-heating and ambient temperature variation limit the achievable accuracy.
In this work, a dynamic compensation method is presented which takes static and dynamic temperature drift effects into account. It significantly reduces the remaining measurement errors. The approach can also be used to improve existing measurement systems.
Roland Wuchrer, Sabrina Amrehn, Luhao Liu, Thorsten Wagner, and Thomas Härtling
J. Sens. Sens. Syst., 5, 157–163, https://doi.org/10.5194/jsss-5-157-2016, https://doi.org/10.5194/jsss-5-157-2016, 2016
Short summary
Short summary
The continuous monitoring of industrial and environmental processes is becoming an increasingly important aspect with both economic and societal impact. To realize this task, spectral-optical sensors with their outstanding properties in terms of sensitivity and reliability are a potential solution. However, for exploiting these sensors in a cost- and energy-efficient sensing system, a miniaturized readout unit is needed. Here we present a card-size, inexpensive, and robust readout electronics.
Johannes Gürtler, Daniel Haufe, Anita Schulz, Friedrich Bake, Lars Enghardt, Jürgen Czarske, and Andreas Fischer
J. Sens. Sens. Syst., 5, 125–136, https://doi.org/10.5194/jsss-5-125-2016, https://doi.org/10.5194/jsss-5-125-2016, 2016
Short summary
Short summary
The interaction of sound and flow enables an efficient noise damping. Understanding this aeroacoustic damping phenomenon requires simultaneous measurement of flow and sound fields. Using a high-speed CMOS camera, two-component flow velocity measurements are performed in a three-dimensional region of interest. The sensor system can simultaneously capture sound and turbulent flow velocity oscillations. The presented measurements reveal that the sound energy is transferred into flow energy.
A. Tempelhahn, H. Budzier, V. Krause, and G. Gerlach
J. Sens. Sens. Syst., 5, 9–16, https://doi.org/10.5194/jsss-5-9-2016, https://doi.org/10.5194/jsss-5-9-2016, 2016
Short summary
Short summary
Infrared cameras based on microbolometer focal plane arrays (FPAs) are the most widely used cameras in thermography. For acceptable measurement uncertainty values, the disturbing influences of changing ambient temperature have to be considered. We propose a TEC-less and shutter-less correction approach based on additional temperature measurements inside the IR camera. The effects on the pixel responsivity and offset voltage are considered separately.
M. Schüler, T. Sauerwald, and A. Schütze
J. Sens. Sens. Syst., 4, 305–311, https://doi.org/10.5194/jsss-4-305-2015, https://doi.org/10.5194/jsss-4-305-2015, 2015
Short summary
Short summary
We study the effect of HMDSO vapor on an SnO2-based gas sensor in temperature cycled operation (TCO). The poisoning can be quantified at early stages with a resolution of ±85 ppm*min using TCO. This approach provides a simple method for early detection of HMDSO poisoning.
The stability of gas discrimination by linear discriminant analysis (LDA) can be improved using normalization, which in turn facilitates a more accurate determination of the poisoning state by hierarchical LDA discrimination.
A. Schuler, T. Hausotte, and Z. Sun
J. Sens. Sens. Syst., 4, 199–208, https://doi.org/10.5194/jsss-4-199-2015, https://doi.org/10.5194/jsss-4-199-2015, 2015
Short summary
Short summary
Measurement tasks of modern micro- and nanometrology with decreasing structure sizes and rising aspect ratios require nanometre-resolving 3-D capable sensors. A 3-D probing system based on electrical interaction is presented which is operated on a nanopositioning system NMM-1. New 3-D measurement procedures for the probing system as well as for micrometrology measurement tasks in general are shown.
A. Dragoneas, L. Hague, and M. Grell
J. Sens. Sens. Syst., 4, 169–177, https://doi.org/10.5194/jsss-4-169-2015, https://doi.org/10.5194/jsss-4-169-2015, 2015
A. Ens and L. M. Reindl
J. Sens. Sens. Syst., 4, 9–16, https://doi.org/10.5194/jsss-4-9-2015, https://doi.org/10.5194/jsss-4-9-2015, 2015
M. Schüler, T. Sauerwald, and A. Schütze
J. Sens. Sens. Syst., 3, 213–221, https://doi.org/10.5194/jsss-3-213-2014, https://doi.org/10.5194/jsss-3-213-2014, 2014
Y. Wang, D. Ewert, T. Meisen, D. Schilberg, and S. Jeschke
J. Sens. Sens. Syst., 3, 113–120, https://doi.org/10.5194/jsss-3-113-2014, https://doi.org/10.5194/jsss-3-113-2014, 2014
D. Griefahn, J. Wollnack, and W. Hintze
J. Sens. Sens. Syst., 3, 105–111, https://doi.org/10.5194/jsss-3-105-2014, https://doi.org/10.5194/jsss-3-105-2014, 2014
J.-M. Boccard, P. Katus, R. Renevier, L. M. Reindl, and J.-M. Friedt
J. Sens. Sens. Syst., 2, 147–156, https://doi.org/10.5194/jsss-2-147-2013, https://doi.org/10.5194/jsss-2-147-2013, 2013
H. Lühr, F. Yin, and R. Bock
J. Sens. Sens. Syst., 2, 9–17, https://doi.org/10.5194/jsss-2-9-2013, https://doi.org/10.5194/jsss-2-9-2013, 2013
Cited articles
Agarwal, S., Kumar, B., and Singh, D.: Non-invasive concealed weapon
detection and identification using V band millimeter wave imaging radar
system, National Conference on Recent Advances in Electronics & Computer
Engineering (RAECE), 13–15 February 2015, Roorkee, India, 258–262,
https://doi.org/10.1109/RAECE.2015.7510202, 2015.
Ahmed, S. S., Schiessl, A., Gumbmann, F., Tiebout, M., Methfesssel, S., and
Schmidt, L.-P.: Advanced microwave imaging, IEEE Microw. Mag., 13, 26–43,
https://doi.org/10.1109/MMM.2012.2205772, 2012.
Albakhali, M. and Moghaddam, M.: 3D SAR focusing for subsurface point
targets, Proc. IGARSS 2009, I-60–I-63, https://doi.org/10.1109/IGARSS.2009.5416944,
2009.
Benetsy, J., Chen, J., and Huang, Y.: Microphone array signal processing,
Springer, Berlin, Germany, https://doi.org/10.1007/978-3-540-78612-2, 2008.
Born, M. and Wolf, E.: Principles of optics, 6th edn., Pergamon Press,
Oxford, UK, 1980.
Cumming, I. G. and Wong, F. H.: Digital processing of synthetic aperture
data, Artech House, Norwood, USA, 2005.
Elvers, B.: Ullmann's polymers and Plastics, Wiley-VCH, Weinheim, Germany,
2016.
Feng, X., Liang, W., Lu, Q., Liu, C., Li, L., Zou, L., and Sato, M.: 3D
velocity model and ray tracing of antenna array GPR, Proc. IGARSS 2010,
4204–4207, https://doi.org/10.1109/IGARSS.2010.5651564, 2010.
Gumbmann, F.: Aktive multistatische Nahbereichsabbildung mit ausgedünnten
Gruppenantennen, PhD Thesis, Friedrich-Alexander University, Erlangen,
Germany, 2011.
Hecht, E.: Optics, 5th edn., Pearson, London, UK, 2002.
Hillger, W., Ilse, D., and Bühling, L.: Industrial applications of
air-coupled ultrasonic technique, 7th International Symposium on NDT in
aerospace, 16–18 November 2015 Bremen, Germany, 1–7, We.2.A.3, 2015.
Qin, K., Yang, C., and Sun, F.: Generalized Frequency Domain Synthetic
Aperture Focusing Technique for Ultrsonic Imaging of Irregularly Layered
Objects, IEEE T. Ultrason. Ferr., 61, 133–146,
https://doi.org/10.1109/TUFFC.2014.6689781, 2014.
Skjelvareid, M. H., Olofson, T., Bikelund, Y., and Larsen, Y.: Synthetic
aperture focusing of ultrasonic data from multlayered media using an omega-k
algorithm, IEEE T. Ultrason. Ferr., 58, 1037–1048,
https://doi.org/10.1109/TUFFC.2011.1904, 2011.
Ullmann, I., Adametz, J., Oppelt, D., and Vossiek, M.: Millimeter Wave Radar
Imaging for Nod-Destructive Detection of Material Defects, Proc. SENSOR 2017,
467–472, https://doi.org/10.5162/sensor2017/D3.3, 2017.
Walker, P. D. and Bell, M. R.: Non-iterative GPR imaging through a non-planar
air-ground interface, Proc. IGARSS 2001, 1527–1529,
https://doi.org/10.1109/IGARSS.2001.976900, 2001.
Short summary
Millimetre-wave radar is an emerging technique for non-destructive testing: it is less costly than X-rays and has no ionizing radiation. Compared to ultrasound it does not require the device under test to be immersed in water. This article presents methods for high-resolution millimetre-wave radar imaging without a priori knowledge of the object's shape. A polymer device with simulated material defects is examined, which could be depicted precisely.
Millimetre-wave radar is an emerging technique for non-destructive testing: it is less costly...
Special issue