Conference Paper

A super-resolution approach of the total focusing method for resolving close flaws

Authors:
  • The phased Array Company
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Abstract

This paper proposes a method to enhance the resolution of images computed from Full Matrix Capture (FMC) datasets widely used in Non-Destructive Evaluation (NDE). The resolution of standard techniques such as Total Focusing Method (TFM) that do not account for the impulse response of transducers is limited. The proposed model exploits the instrumental signature of the transducers in order to link linearly the FMC dataset to the reflectivity of the material. An ill-posed inverse problem is hence formulated due to the limited bandwidth of the transducers. The final image is obtained iteratively by inverting the model using a sparse prior representing the small number of scatterers in the specimen under test. Experimental results are given in order to compare the proposed method with the well-known TFM. A specific application of close flaw separation is presented and shows that the proposed approach is able to resolve two close scatterers separated by 𝜆/4.

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Inverse Problem of Ultrasound Beamforming With Sparsity Constraints and Regularization
  • E Oskan
  • V Vishnevsky
  • O Goksel
Oskan, E., Vishnevsky, V., Goksel, O., 2018, "Inverse Problem of Ultrasound Beamforming With Sparsity Constraints and Regularization", IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 65(3), pp. 356-365.