Characterization and Quantitative Evaluation of Surface Cracks on Steel Plates Based on Eddy Current Pulsed Thermography

作者：Tengyan Xi, Ping Wang, Yan Shi, Chunlian Zhan, Weihu Zhou · 发表于：IEEE Transactions on Instrumentation and Measurement · 年份：2025 · DOI：10.1109/TIM.2025.3588987 · 被引用次数：6 · 研究领域：Computer Science

Eddy current pulsed thermography (ECPT) is an emerging nondestructive testing technique widely applied for surface defect detection in metallic materials. This article proposes a multistage synergistic optimization method to address key technical challenges, including background noise, low defect contrast, and complex thermal gradients. The proposed method comprises three stages: preprocessing, feature extraction, and postprocessing. In the preprocessing stage, the excitation peak frame is dynamically selected using image entropy difference, static background noise is suppressed through differential operations, and a geometric prior mask is generated via edge detection. The feature extraction stage uses the augmented Lagrangian multiplier (ALM) method to solve a differential image-based robust principal component analysis (DI-RPCA) model. This process reconstructs a sparse matrix that preserves the complete defect morphology while simultaneously eliminating high-frequency noise from the coil region. In the postprocessing stage, adaptive histogram equalization is applied to the sparse matrix to enhance indication edge details, and a local spatial consistency-based dual thresholding segmentation (LSC-DTS) method is designed for efficient anomaly-background separation. It combines adaptive thresholding based on image grayscale distribution with an area-based filtering mechanism for defect candidate regions. The experimental results on steel plates with natural fatigue cracks dem...