LSDC-RC-RAPID: An Improved Probabilistic Reconstruction Approach for Pipeline Corrosion Detection with UGWT

Corrosion is an irreversible form of damage to pipe materials, which leads to the degradation of their mechanical and chemical properties. Corrosion damage reduces the lifespan of materials and, in~some cases, can even lead to catastrophic failures. Therefore, it~is essential to detect corrosion damages and develop effective preventative measures to maintain the structural integrity of the pipelines. In~recent times, ultrasonic guided wave testing techniques have been employed to detect and monitor corrosion damage as they are useful for scanning large areas and conducting tomographic analyses. The obtained guided wave signals are then analyzed using the reconstruction algorithm for probabilistic inspection of damage (RAPID) to obtain imaging of the damages. However, conventional RAPID assigns the same signal difference coefficient (SDC) to all reconstruction points along a sensing path, which limits its ability to capture localized signal variations. In~addition, it~lacks a mechanism for evaluating signal reliability, making it prone to false positives caused by noise. Thus, this article proposes an improved RAPID-based algorithm by employing a local SDC (LSDC) and reliability coefficient (RC) to ensure that damage is accurately detected. The LSDC is employed to enhance the sensitivity to damage by capturing localized signal variations, while the RC is developed to weigh the signal reliability. The experimental results demonstrate that the proposed method accurately predicts corrosion locations. It~maintained a strong overlap between the predicted and the actual defect locations, with an overlapping rate (OR) between 73.02% and 79.43% throughout all cycles.