Motion-based filtering of magneto-optic imagers

Park, Unsang; Удпа, Лалита; Stockman, George C.

doi:10.1016/j.imavis.2003.10.001

Cited by 26 publications

(8 citation statements)

References 6 publications

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“…15.57. The raw image obtained from the MOI acquisition system is applied to the motion-based filter [34] to remove the background noise associated with domain structures in the MO sensor [13]. The filtered image is enhanced and thresholded to obtain a binary image, which is used in the subsequent rivet hole detection and classification modules.…”

Section: Mo Image Post-processing Enhancement and Automatic Detectionmentioning

confidence: 99%

“…34 shows the normal component of the predicted magnetic flux densities with the edge effect due to the finite size of the foil. The effects of finite foil versus infinite foil are summarized as follows: (1) The signal peak value is much smaller in case of using finite foil compared with that using infinite foil; (2) the binary images with infinite foil and those with finite foil are comparable if the threshold is chosen to be a percentage of the peak value instead of an absolute value (seeFig.…”

mentioning

confidence: 99%

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Principles of Magneto-optic Imaging and Its Applications

Deng

Cheng²,

Xuan

et al. 2015

Integrated Imaging and Vision Techniques for Industrial Inspection

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Magneto-optic imaging (MOI) is an emerging hybrid imaging technique that innovatively generates two-dimensional images by combining electromagnetic and optical energies. It has been widely used in detecting surface and subsurface cracks and corrosion in aircraft skins for nondestructive testing purpose. The merits of the MOI that make it attractive include rapid and large-area inspection, insensitivity to liftoff variation, and easy interpretation in contrast to the complex impedance data of conventional eddy current inspections. The early instrument provides binary images of the anomalies based on eddy current induction techniques and an MO sensor using the Faraday's rotation effect. This chapter will give a comprehensive review on this relatively new sensing technology and discuss the recent advances on MOI including the development of novel optical sources and magnetic film materials for various applications, the integration of MOI sensors with automated systems, and the state-of-the-art post-processing algorithms.

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Section: Mo Image Post-processing Enhancement and Automatic Detectionmentioning

confidence: 99%

mentioning

confidence: 99%

Principles of Magneto-optic Imaging and Its Applications

Deng

Cheng²,

Xuan

et al. 2015

Integrated Imaging and Vision Techniques for Industrial Inspection

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“…Section 3 introduces and deepens the denoising of MO images by using two image processing techniques: the former is based on ICA [9][10][11], the latter is a self-implemented adaptive homomorphic filter (AHF). Both were compared with the motion-based filtering (MBF) [12,13], a well-known technique able to reduce static noise in images. Finally, in Section 4, the performances of the proposed approaches are discussed.…”

Section: Introductionmentioning

confidence: 99%

Heuristic Enhancement of Magneto-Optical Images for NDE

Cacciola

Megali

Pellicanó

et al. 2010

EURASIP J. Adv. Signal Process.

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The quality of measurements in nondestructive testing and evaluation plays a key role in assessing the reliability of different inspection techniques. Each different technique, like the magneto-optic imaging here treated, is affected by some special types of noise which are related to the specific device used for their acquisition. Therefore, the design of even more accurate image processing is often required by relevant applications, for instance, in implementing integrated solutions for flaw detection and characterization. The aim of this paper is to propose a preprocessing procedure based on independent component analysis (ICA) to ease the detection of rivets and/or flaws in the specimens under test. A comparison of the proposed approach with some other advanced image processing methodologies used for denoising magneto-optic images (MOIs) is carried out, in order to show advantages and weakness of ICA in improving the accuracy and performance of the rivets/flaw detection.

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“…4 shows this intermittent square pulse of the exciting current. Here the pulse frequency is 2 kHz; t 0 is the duration of the square pulse; and t is the intermittent time, which is equal to 1:5 t 0 ; this value is acquired from experiments [7,8]. …”

Section: Introductionmentioning

confidence: 99%

Research on visual detection technology using eddy current magnet excitation device

Cheng

Rong

2009

2009 International Conference on Applied Superconductivity and Electromagnetic Devices

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A visual method for detecting invisible and buried micro-flaws under fine metallic surface is described. A new magneto-optic microscope that has a laser source, a CCD camera, and an eddy current magnet excitation device is developed for this work. A pulse generator supplies an intermittent square pulse to induce the magnet excitation device, which can intensify eddy currents yet reduce the working temperature of the exciting coil and specimens. The magnetic field variation produced by the imbedded defect causes a rotation of the polarization plane of the reflected beam. Therefore the reflected beam carries an image of the defect, which is received by a CCD camera. Now the imperceptible flaws in subsurface of mental product are visually tested. Image edge processing approaches are designed to enhance the effect. Experimental tests have been done and the method presented is evaluated by the experimental results.

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Motion-based filtering of magneto-optic imagers

Cited by 26 publications

References 6 publications

Principles of Magneto-optic Imaging and Its Applications

Principles of Magneto-optic Imaging and Its Applications

Heuristic Enhancement of Magneto-Optical Images for NDE

Research on visual detection technology using eddy current magnet excitation device

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