Single-side access tomography for evaluating interior defect of concrete

Chai, Hwa Kian; Aggelis, Dimitrios G.; Momoki, Shohei; Kobayashi, Yoshikazu; Shiotani, Tomoki

doi:10.1016/j.conbuildmat.2010.03.003

Cited by 42 publications

(25 citation statements)

References 11 publications

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“…Moreover, the high permittivity of the asteroid minerals [17,18,19,20] is likely to lead to strongly randomized or noisy reflections ‡ due to which the present inversion strategy utilizing the direct part of the signal can be advantageous [5]. In addition to asteroid tomography, other potential applications of the present sparse source inversion approach include on-site material testing and inspection [21,22,23,24,25,26,27], biomedical ultrasonography [28,29,30,31,32], as well as plenty of atmospheric, pedospheric, geological, and biological investigations utilizing travel time data [33,34,35], such as recovery of the root-zone structure of a tree [36]. The objectives above were studied in a laboratory experiment in which three 22-41 mm onyx stones were to be detected from the central part of a 150 mm synthetic reson cube based on travel time of a 55 kHz (35 mm wavelength) ultrasonic signal.…”

Section: Introductionmentioning

confidence: 99%

Sparse source travel-time tomography of a laboratory target: accuracy and robustness of anomaly detection

Pursiainen¹,

Kaasalainen²

2014

Inverse Problems

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Abstract. This study concerned conebeam travel-time tomography. The focus was on a sparse distribution of signal sources that can be necessary in a challenging in situ environment such as in asteroid tomography. The goal was to approximate the minimum number of source positions needed for robust detection of refractive anomalies, e.g., voids within an asteroid or a casting defects in concrete. Experimental ultrasonic data were recorded utilizing as a target a 150 mm plastic cast cube containing three stones with diameter between 22 and 41 mm. A signal frequency of 55 kHz (35 mm wavelength) was used. Source counts from one to six were tested for different placements. Based on our statistical inversion approach and analysis of the results, three or four sources were found to lead to reliable inversion. The source configurations investigated were also ranked according to their performance. Our results can be used, for example, in the planning of planetary missions as well as in material testing.

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Section: Introductionmentioning

confidence: 99%

Sparse source travel-time tomography of a laboratory target: accuracy and robustness of anomaly detection

Pursiainen¹,

Kaasalainen²

2014

Inverse Problems

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“…biomedical microwave or ultrasonic imaging [5,6,7,8,9] and on-site material testing and inspection [10,11,12,13]. Our focus was on the first one with the central objective to find a robust imaging approach that can be implemented within a restricted in situ energy supply and tight mission payload limits [14].…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic 3D subsurface imaging with source sparsity for a synthetic object

Pursiainen

Kaasalainen

2015

Inverse Problems

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Abstract. This paper concerns electromagnetic 3D subsurface imaging in connection with sparsity of signal sources. We explored an imaging approach that can be implemented in situations that allow obtaining a large amount of data over a surface or a set of orbits but at the same time require sparsity of the signal sources. Characteristic to such a tomography scenario is that it necessitates the inversion technique to be genuinely three-dimensional: For example, slicing is not possible due to the low number of sources. Here, we primarily focused on astrophysical subsurface exploration purposes. As an example target of our numerical experiments we used a synthetic small planetary object containing three inclusions, e.g. voids, of the size of the wavelength. A tetrahedral arrangement of source positions was used, it being the simplest symmetric point configuration in 3D. Our results suggest that somewhat reliable inversion results can be produced within the present a priori assumptions, if the data can be recorded at a specific resolution. This is valuable early-stage knowledge especially for design of future planetary missions in which the payload needs to be minimized, and potentially also for the development of other lightweight subsurface inspection systems.

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“…Styrofoam plates of 300 mm diameter were included at specific locations. The same specimen was used for a different purpose, as reported elsewhere [26]. In order to simulate boundary free experiment, in this current study the measurements were limited to two 200 Â 200 Â 300 mm 3 portions near the middle of the specimen, which included one quarter of the defect.…”

Section: Experiments Detailmentioning

confidence: 99%