Eddy current imaging of surface-breaking structures

Clear Eddy Current Flaw Image Using Computerized Tomography Inversion Technique

“…(2) where (u,v) denotes spatial frequency domain and B(u,v), D(u,v), and P(u,v) are Fourier transforms of b(x,y), d(x,y), and p(x,y) respectively. Equation (2) leads to the following equation.…”

“…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).…”

“…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. Because a large PSF complicates the process of defect characterization, deconvolution techniques using the image PSF have previously been applied [2] to reduce effects of probe blurring. Success of such processing depends on in-depth understanding of the imaging system response and on whatever simplifying approximations can be made.…”

Eddy current probe evaluation: experimental measurements and system interaction

“…In order to meet the new goals, all aspects of an eddy current inspection system must be addressed from probe selection and mechanical scanning noise to system electronics and signal processing. It has previously been shown [1,2] timt imaging techniques provide improved flaw detection capability and also may be used to opthnize system performance. This paper describes work that combines imaging with probe measurements to analyze eddy current prob es and system performance from a practical point of view.…”