Application of magneto-optical method for real-time visualization of eddy currents with high spatial resolution for nondestructive testing

Radtke, U.; Zielke, R.; Rademacher, H.-G.; Crostack, H.‐A.; Hergt, R.

doi:10.1016/s0143-8166(01)00052-5

Cited by 39 publications

(11 citation statements)

References 3 publications

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“…This technique was proposed and developed in the 1990s. 223 The propagation of light through a magnetic field is used to image target objects (e.g., defects or cracks in the surface of an object). A pulse generator sends an alternating current to the excitation coil which induces eddy currents in the sample.…”

Section: Future Perspectivesmentioning

confidence: 99%

“…Magneto-optic imaging (MOI) is another hybrid imaging technique that combines an electromagnetic effect (eddy current or magnetic flux leakage) and the Faraday effect to generate a 2D image. This technique was proposed and developed in the 1990s . The propagation of light through a magnetic field is used to image target objects ( e .…”

Section: Future Perspectivesmentioning

confidence: 99%

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Medical Imaging of Microrobots: Toward In Vivo Applications

et al. 2020

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Medical microrobots (MRs) have been demonstrated for a variety of non-invasive biomedical applications, such as tissue engineering, drug delivery, and assisted fertilization, among others. However, most of these demonstrations have been carried out in in vitro settings and under optical microscopy, being significantly different from the clinical practice. Thus, medical imaging techniques are required for localizing and tracking such tiny therapeutic machines when used in medical-relevant applications. This review aims at analyzing the state of the art of microrobots imaging by critically discussing the potentialities and limitations of the techniques employed in this field. Moreover, the physics and the working principle behind each analyzed imaging strategy, the spatiotemporal resolution, and the penetration depth are thoroughly discussed. The paper deals with the suitability of each imaging technique for tracking single or swarms of MRs and discusses the scenarios where contrast or imaging agent's inclusion is required, either to absorb, emit, or reflect a determined physical signal detected by an external system. Finally, the review highlights the existing challenges and perspective solutions which could be promising for future in vivo applications.

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Section: Future Perspectivesmentioning

confidence: 99%

Section: Future Perspectivesmentioning

confidence: 99%

Medical Imaging of Microrobots: Toward In Vivo Applications

et al. 2020

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“…Illumination was done quasi-stroboscopically with a diode laser modulated with the excitation frequency. Details of the method were reported by Radtke et al [18]. An example demonstrating the validity of the method is shown in Fig.…”

Section: Applications Of Magneto-optical Garnet Layersmentioning

confidence: 94%

“…Here an analogue correlator technique with a continuously controllable delay has clear advantages. Our work on epitaxial growth of magneto-optic garnet layers is part of a system development for real-time visualisation of eddy currents with high spatial resolution for Non-Destructive Testing [18]. In the following we will give an up to date summary of bismuth substituted yttrium iron garnet (BiYIG) with general composition (Y 3-x Bi x )(Fe 5-y-z Ga y Al z )O 12 .…”

mentioning

confidence: 99%

Garnet layers prepared by liquid phase epitaxy for microwave and magneto‐optical applications – a review

Aichele¹,

Lorenz

Hergt³

et al. 2003

Cryst. Res. Technol.

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The magnetic iron garnets possess two outstanding properties, an excellently narrow linewidth of the ferromagnetic resonance and a magneto-optical activity that is without competition when the iron garnet is substituted with bismuth. Here the growth of bismuth substituted iron garnet layers with a bismuth content of up to 1.8 formula units is reported. The influence of solution compositions and undercooling on the growth and bismuth incorporation is discussed. Morphological instabilities due to misfit stress are avoided by the use of lattice-matched substrates. Two applications of iron garnet layers, namely a electronically controllable magnetostatic delay line for the communication technology in the GHz range and magneto-optic garnet sensor layers for real-time visualisation of eddy currents with high spatial resolution for the non-destructive evaluation are presented. Furthermore the detection, measurement, and visualisation of magnetic fields by magneto-optic garnet layers are reviewed. Dedicated to Professor K. W. Benz on the occasion of his 65th birthday.

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“…Based on the Faraday effect, magneto-optical imaging transforms the magnetic leakage field into a light intensity map to visualize defects [32,34]. That is, when the incident polarized light I 0 passes through the magnetic field, it will produce a rotation angle θ.…”

Section: Principle Of Magneto-optical Imagingmentioning

confidence: 99%

Magneto-Optical Imaging of Arbitrarily Distributed Defects in Welds under Combined Magnetic Field

Gao

Tian

et al. 2022

Metals

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Using the traditional magneto-optical detection methods, micro-weld defects parallel with the magnetic field direction may be overlooked. In order to overcome this, a non-destructive testing method based on magneto-optical imaging under a vertical combined magnetic field (VCMF) is proposed. To demonstrate this, the experimental results of the magneto-optical imaging of weld defects excited by a vertical combined magnetic field (VCMF) or parallel combined magnetic field (PCMF) are compared with those of traditional magnetic fields (constant magnetic field (CMF), alternating magnetic field (AMF), and rotating magnetic field (RMF)). It is found that the magneto-optical imaging under a VCMF can accurately detect weld defects of any shape and distribution. In addition, the center difference method is used to eliminate the influence of noise on the defect contour extraction of magneto-optical images, and the active contour of weld defects in the magneto-optical images is extracted. The results show that many noises can be identifiedby the robustness of the level set method, operating in low-pass filtering, so that much information that is usually lost can be retained.

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Application of magneto-optical method for real-time visualization of eddy currents with high spatial resolution for nondestructive testing

Cited by 39 publications

References 3 publications

Medical Imaging of Microrobots: Toward In Vivo Applications

Medical Imaging of Microrobots: Toward In Vivo Applications

Garnet layers prepared by liquid phase epitaxy for microwave and magneto‐optical applications – a review

Magneto-Optical Imaging of Arbitrarily Distributed Defects in Welds under Combined Magnetic Field

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