Sebastien Robert

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In the present work, the Synthetic Transmit Aperture (STA) imaging is combined with the Decomposition of the Time Reversal Operator (DORT) method to image a coarse grained austenitic-ferritic steel using a contact transducer array. The highly heterogeneous structure of this material produces a strong scattering noise in ultrasound images. Furthermore, the(More)
In this work, defects in a high density polyethylene pipe are imaged with the total focusing method. The viscoelastic attenuation of this material greatly reduces the signal level and leads to a poor signal-to-noise ratio due to electronic noise. To improve the image quality, the decomposition of the time reversal operator method is combined with the(More)
The layer-multiple-scattering method is developed to study wave propagation through two-dimensional lattices of cylindrical inclusions in an elastic medium. The lattices are a series of periodically spaced infinite one-dimensional periodic gratings (or rows) of inclusions. The layer-multiple-scattering method allows the analysis of the reflection and(More)
V. Twersky developed in the sixties a theory describing the reflection and transmission process of scalar plane waves from slab-like regions of randomly distributed scatterers. The theory, which is based on Foldy's approximation and neglects " hole corrections " , is an alternative approach to an exact calculation of multiple scattering that fails when the(More)
This paper describes a new ultrasonic array imaging method for Non-Destructive Testing (NDT) which is derived from the medical Plane Wave Imaging (PWI) technique. The objective is to perform fast ultrasound imaging with high image quality. The approach is to transmit plane waves at several angles and to record the back-scattered signals with all the array(More)
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