Ultrasound Tomography Based on the Inverse Coefficient Problem as a Way to Combat Pattern Noiseстатья
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Дата последнего поиска статьи во внешних источниках: 15 февраля 2024 г.
Аннотация:The paper proposes to use the ultrasound tomography method based on the solution of theinverse coefficient problem to reduce the level of pattern noise. Mathematical models used in ultra-sound tomography well describe such physical effects as refraction, diffraction, and rescattering.It is logical to expect that reconstruction of the internal structure of metallic samples using ultrasoundtomography is more efficient compared to digital antenna focusing (DFA) techniques. Due to thenonlinearity of the inverse problem of ultrasound tomography, an iterative MultiStage method is usedto ensure convergence to the global minima of the residual functional. The paper presents the resultsof numerical experiments to reconstruct the image of the internal structure of a welded joint that maycontain side drilled holes and crack models. A domain of welded metal is represented in the formof sections constructed according to the principle of Voronoi diagrams. In each section, the velocityis constant and its value is randomly distributed. In the model adopted in the paper, the pattern noiseis formed due to multiple scattering at the boundaries of sections with different sound velocities. It wasassumed that the antenna array is located on the outer surface of the test object of known thickness.The obtained results show that the tomographic method allows one to determine the shape and speedof sound in low-contrast reflectors, for which the DFA method is ineffective.