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Robust Reconstruction of Medical Ultrasound Images in The Presence of Transducer Faults

Zare Dehabadi, Mohammad Saeed | 2023

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 56586 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Jahed, Mehran
  7. Abstract:
  8. Medical ultrasound imaging is one of the common imaging methods in modern medicine, which is used to diagnose and even treat some diseases due to its cheapness and harmlessness. Medical ultrasound transducer arrays have a significant error rate. They are a major cause of failure in ultrasound imaging systems. This problem causes a noticeable decrease in the quality of the images and medical misdiagnoses. The topics of accurate detection of the location and severity of the error or failure, as well as the compensation for weak transducers by signal processing methods, have received less attention from predecessor researchers. In this thesis, an innovative method for accurate error detection is proposed by measuring the acoustic pressure from the arrays. This method is based on solving an optimization problem, which is defined by acoustic field equations. Also, an adaptive beamforming method is proposed for robust reconstruction of medical ultrasound images in the presence of transducer errors. In this method, the array elements are weighted in such a way that the pressure from the array is very similar to a healthy array. The efficiency and high accuracy of the proposed methods are shown using simulated data and practical experiments. Also, a method based on adaptive non-blind signal deconvolution, by measuring the electromechanical impulse response of a weak transducer and the response corresponding to an intact transducer. It can eliminate the negative effect of weak transducers, which suffer from low sensitivity, without replace or repair the transducer. The electrical fatigue of piezoelectric materials has been investigated as the main factor in the weakness of transducers, and the mentioned proposed method has been applied in the simulated, practical, and clinical dataset. The results show significant restoration of image quality in the face of weak transducers
  9. Keywords:
  10. Medical Ultrasound Images ; Image Reconstruction ; Beam Shaping ; Beamforming ; Piezoelectric Transducers ; Signal Deconvolution ; Acoustic Field Pressure ; Electrical Fatigue in Piezoelectric Materials ; Fault Detection and Correction

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