Sung-Jin Song

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Among various kinds of image denoising methods, the Perona–Malik model is a representative Partial Differential Equation based (PDE-based) algorithm which effectively removes the noise as well as having edge enhancement simultaneously through anisotropic diffusion controlled by the diffusion coefficient. However, the unstable behavior of the Perona–Malik(More)
The identification of ultrasonic flaw signals is a difficult task in the angle beam ultrasonic testing of welded joints due to the presence of non-relevant signals from the geometric reflectors such as weld-roots and counter-bores. This paper describes a new approach to identify ultrasonic flaw signals in such a problematic situation. A similarity function(More)
Phased array transducers are quite often mounted on solid wedges with specific angles in many practical ultrasonic inspections of thin plates <10 mm in their thickness or welded joints with convex crowns. For the reliable application of phased array techniques with testing set-up, it is essential to have thorough understanding on the characteristics of(More)
A plate of Inconel 600 was interrogated using the resonant ultrasound spectroscopy (RUS) and the reflected leaky Lamb waves (LLW). It was found that the plate used in the present work has anisotropy in its material properties by the RUS. The longitudinal and the transverse wave velocities of the Inconel 600 plate were determined by the RUS, ultrasonic(More)
To date, ultrasonic measurement models have primarily treated systems where circular transducers are used. Recently, however, a highly efficient ultrasonic beam model for a rectangular transducer has also become available where the transducer is represented as a superposition of a relatively few Gaussian beams. Thus, using the multi-Gaussian beams, we(More)
Inspection of unpiggable pipeline becomes one of major issues in the gas pipelines industry. Remote field eddy current testing (RFECT) has strong potential for inspecting unpiggable pipelines among the various NDE methods. Thus, in this study, design of RFECT system including driving coil, sensing coil and passive scanning module and intial experimental(More)
The model-based interpretation tools for eddy current testing (ECT) signals have been developed by the novel combination of neural networks and finite element modeling for quantitative flaw characterization in steam generator tubes. The performance of inversion system strongly relies on the databases that had been used in the implementation of the specific(More)
Material degradation due to corrosion-fatigue was evaluated nondestructively using backscattered Rayleigh surface wave. A corrosion-fatigue test was carried out for the specimens made of thermo-mechanically controlled process steel in 3.5 wt.% NaCl solution at 25 degrees C. The Backscattering profile, which is the amplitude variation of backscattered(More)