High resolution SQUID imaging of current and magnetization distributions

Tan, S.; Ma, Yanxue; Thomas, Ian M.; Wikswo, John P.

doi:10.1109/77.233579

Cited by 14 publications

(9 citation statements)

References 5 publications

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“…Because of that a great deal of work has been devoted to develop different signal processing algorithms for different cases [3], [9], [10]. As also stated before, in this work we are focusing on the problems in which knowing the 2-D scanning result of a single hole, the result of other scans over samples with different distribution of such holes are going to be identified.…”

Section: Signal Processing Approachesmentioning

confidence: 99%

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FEM enhanced signal processing approach for pattern recognition in the SQUID based NDE system

Sarreshtedari

Jahed

Hosseni

et al. 2010

J. Phys.: Conf. Ser.

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Abstract. An efficient Non-Destructive Evaluation algorithm has been developed in order to extract the required information for pattern recognition of defects in the conductive samples. Using high-Tc gradiometer RF-SQUIDs in unshielded environments and incorporating an automated two dimensional non-magnetic scanning robot, samples with different intentional defects have been tested. We have used a developed noise cancellation approach for the improvement of the effectiveness of the used inverse-problem technique. In this approach we have used a well examined Finite Element Method (FEM) to apply a noise reduction filtering on the obtained raw magnetic image data before incorporating the signal processing analysis. By applying this noise cancellation filter and incorporating three different signal processing algorithms and comparing the results of the predicted images by the pattern of the intentionally made defects, we have investigated the ability of these methods for pattern recognition of unknown defects.

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Section: Signal Processing Approachesmentioning

confidence: 99%

“…Then by using the inverse filtering in the frequency domain the unknown function could be found [10], [11]. In our case, the resulted scan of the sample is assumed to be the convolution of a single hole response as the convolving filter with the unknown arbitrary distribution of impulses.…”

Section: Signal Processing Approachesmentioning

confidence: 99%

FEM enhanced signal processing approach for pattern recognition in the SQUID based NDE system

Sarreshtedari

Jahed

Hosseni

et al. 2010

J. Phys.: Conf. Ser.

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“…In this paper, we describe the design and development of our susceptometer and present preliminary data. Further experiments with the susceptometer are reported elsewhere [6,8,9]. (1) where B'M is the field due to the magnet tion 1.…”

Section: Introductionmentioning

confidence: 99%

“…In conjunction with deconvolution algorithms [6], it provides images of the susceptibility distribution in a two-dimensional sample; with tomographic techniques [7], it will provide threedimensional susceptibility images. In this paper, we describe the design and development of our susceptometer and present preliminary data.…”

Section: Introductionmentioning

confidence: 99%

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A high resolution imaging susceptometer

Thomas

Lauder

et al. 1993

IEEE Trans. Appl. Supercond.

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High resolution magnetic susceptibility imaging is a new technique for investigating the composition of diamagnetic and paramagnetic objects. It might contribute to the nondestructive evaluation of critical components by identifying both surface and internal defects. In order to demonstrate the technique, we have attached magnetizing coils to our high resolution MicroSQUID magnetometer. With our present system, we can apply a nearly uniform field of 0.3 mT, 2.0-2.5 mm below the 3 mm diameter sensing coils. By placing a sample in this applied field and scanning, MicroSQUID measures the local magnetic field variations caused by the spatial distribution of magnetic susceptibility in the sample. The system has sufficient sensitivity to image susceptibility-induced field changes equal to 3 x of the applied field, in a 100 Hz bandwidth. We describe the concept of susceptibility imaging and present preliminary data.

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