Eddy current imaging

Clear Eddy Current Flaw Image Using Computerized Tomography Inversion Technique

“…Needs of high accuracy testing have been making eddy current testing use precise scanning of the probes. Flaw imaging has been used in eddy current testing in order to identify small flaws [1][2][3][4][5][6][7][8]. However, the eddy current testing using the conventional pancake coil probe provides only blurred images of flaws.…”

Probe footprint estimation in eddy-current imaging

“…Eddy-current imaging has been described in detail in previous publications [1,2,3]. As with other imaging systems, the image of an object represents blurring of the structures of the object by the system point spread function (PSF).…”

“…Previous work [1] has used images of a small circular hole to demonstrate the poor spatial resolution of eddy-current probes compared with the size of defect they are being used to detect. The probe "footprint" evident in such images was used to estimate the probe active area and to approximate the 2-D probe-system PSF, or impulse response.…”

New Signal Processing Scheme for the Analysis of Electromagnetic Images

“…Recent years have witnessed increasing interest in the development of imaging techniques for characterizing defects. As an example, eddy current imaging methods involve araster scan of the surface of the test specimen to obtain a two dimensional image whose elements represent the real or imaginary components or alternatively the magnitude or phase of the impedance of the eddy current probe [4,5]. In the case of magnetostatic imaging methods, the specimen under test is scanned by a flux sensitive transducer such as a Hall probe.…”