文献类型：期刊文献

英文题名：MVDR-Integrated TFM for Defect Detection in Geometrically Shadowed Regions

作者：Li, Wei[1];Hu, Zheng[1];Teng, Da[2];Xiang, Yanxun[1]

机构：[1]East China Univ Sci & Technol, Sch Mech & Power Engn, Shanghai Key Lab Intelligent Sensing & Detect Tech, Shanghai 200237, Peoples R China;[2]Natl Innovat Ctr Par Excellence, Inst Adv Ultrason Technol, Shanghai 201203, Peoples R China

年份：2026

卷号：26

期号：12

起止页码：18946

外文期刊名：IEEE SENSORS JOURNAL

收录：;EI(收录号：20262120766709);WOS:【SCI-EXPANDED(收录号:WOS:001796295800012)】；

基金：This work was supported by the National Natural Science Foundation of China under Grant 12304511, Grant 12404527, and Grant 12327807.

语种：英文

外文关键词：Arrays; Interference; Acoustics; Modeling; Superresolution; Covariance matrices; Image sensors; Noise; Phased arrays; Array signal processing; Keywords

摘要：Detecting defects in geometrically shadowed regions remains an unavoidable challenge for ultrasonic array imaging using the total focusing method (TFM). To address this limitation, the MVDR-TFM method is proposed in this work, in which minimum variance distortionless response (MVDR) beamforming is integrated into the TFM framework. By minimizing the output power under a distortionless constraint, interference from strong near-field scatterers is suppressed, and sidelobe leakage is reduced, thereby enhancing defect visibility in shadowed areas. In an L-shaped specimen, slot-type defects under the structural barrier are successfully identified by the proposed method, whereas conventional TFM cannot identify these. In terms of contrast ratio (CR) and contrast-to-noise ratio (CNR), the proposed method achieves an improvement of 40.44% and 80.34% over the conventional method, respectively. For super-resolution imaging of two side-drilled holes of 1 mm diameter with a 1 mm spacing below the Rayleigh limit, the peak-to-valley amplitude difference of the resulting lateral cross-sectional profile is increased by 10.53 dB with the proposed method compared to TFM. These results demonstrate improved defect detectability and resolvability of the MVDR-TFM method, enabling more reliable ultrasonic array inspections.