PMID- 36764064 OWN - NLM STAT- PubMed-not-MEDLINE DCOM- 20230314 LR - 20230314 IS - 1874-9968 (Electronic) IS - 0041-624X (Linking) VI - 131 DP - 2023 May TI - Detection of defects in highly attenuating materials using ultrasonic least-squares reverse time migration with preconditioned stochastic gradient descent. PG - 106930 LID - S0041-624X(23)00006-9 [pii] LID - 10.1016/j.ultras.2023.106930 [doi] AB - Accurate detection and characterization of defects in high-density polyethylene (HDPE) pipe materials are very important in assessing the structural integrity of critical structures in the nuclear industry. One specific challenge here is the presence of the viscoelastic attenuation of this material, which can lead to resolution degradation and loss of detail in ultrasound imaging. In this work, an effective ultrasonic imaging technique using the least-squares reverse time migration with preconditioned stochastic gradient descent (LSRTM-PSGD) is developed to improve image quality. Compared with standard ultrasonic imaging methods which only consider the direct ray path of ultrasound, least-squares reverse time migration (LSRTM) is a powerful wave-equation-based approach and it has the ability to account for rapid spatial velocity variations and to utilize all wavefield information. The LSRTM is an inversion method, which iteratively updates the reflectivity model by minimizing the modeled data and measured data. The proposed LSRTM-PSGD combines the advantages of stochastic gradient descent (SGD) and adaptive learning rate. The SGD updates the parameter on each transmitter and the fluctuation of SGD can enable it to reach a better minimum, thus improving the imaging quality. Compared with the conventional LSRTM algorithm using a fixed step size, the proposed LSRTM-PSGD algorithm can use the adaptive moment estimation to calculate the adaptive learning rate for the parameter, thereby updating the parameter appropriately. The performance of the LSRTM-PSGD algorithm is tested with experimental data. The results show high-quality reconstructed images with good resolution for defect identification in HDPE pipe materials, especially for deep defects. CI - Copyright (c) 2023 Elsevier B.V. All rights reserved. FAU - Rao, Jing AU - Rao J AD - Key Laboratory of Precision Opto-mechatronics Technology of Education Ministry, School of Instrumentation and Opto-Electronic Engineering, Beihang University, Beijing 100191, China; School of Engineering and Information Technology, The University of New South Wales, Canberra, ACT 2600, Australia. Electronic address: zdraojing@gmail.com. FAU - Tao, Yangji AU - Tao Y AD - Zhejiang Academy of Special Equipment Science, Hangzhou 310020, China. FAU - Sun, Yan AU - Sun Y AD - Institute of Laser & Optoelectronics, School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China. FAU - Miao, Cunjian AU - Miao C AD - Zhejiang Academy of Special Equipment Science, Hangzhou 310020, China. FAU - Wang, Wenlong AU - Wang W AD - Harbin Institute of Technology, Center of Geophysics, Department of Mathematics and Artificial Intelligence Laboratory, Harbin 150001, China. Electronic address: wenlong.wang2015@gmail.com. LA - eng PT - Journal Article DEP - 20230204 PL - Netherlands TA - Ultrasonics JT - Ultrasonics JID - 0050452 SB - IM OTO - NOTNLM OT - Defect characterization OT - Highly attenuating materials OT - Least-squares reverse time migration OT - Stochastic gradient descent OT - Ultrasonic imaging COIS- Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. EDAT- 2023/02/11 06:00 MHDA- 2023/02/11 06:01 CRDT- 2023/02/10 18:07 PHST- 2022/08/05 00:00 [received] PHST- 2022/12/29 00:00 [revised] PHST- 2023/01/13 00:00 [accepted] PHST- 2023/02/11 06:00 [pubmed] PHST- 2023/02/11 06:01 [medline] PHST- 2023/02/10 18:07 [entrez] AID - S0041-624X(23)00006-9 [pii] AID - 10.1016/j.ultras.2023.106930 [doi] PST - ppublish SO - Ultrasonics. 2023 May;131:106930. doi: 10.1016/j.ultras.2023.106930. Epub 2023 Feb 4.