Adaptive Signal Analysis for Automated Subsurface Defect Detection Using Impact Echo in Concrete Slabs

TL;DR

This study introduces an automated, adaptive signal processing method for detecting subsurface defects in concrete slabs using Impact Echo signals, achieving high accuracy and robustness with minimal manual effort.

Contribution

It presents a novel adaptive thresholding and clustering framework that improves defect detection in concrete using Impact Echo signals, enhancing scalability and automation.

Findings

F1-score up to 0.95 indicates high detection accuracy.

AUC-ROC up to 0.83 demonstrates strong classification performance.

Method effectively identifies defect-prone regions with minimal false positives.

Abstract

This pilot study presents a novel, automated, and scalable methodology for detecting and evaluating subsurface defect-prone regions in concrete slabs using Impact Echo (IE) signal analysis. The approach integrates advanced signal processing, clustering, and visual analytics to identify subsurface anomalies. A unique adaptive thresholding method tailors frequency-based defect identification to the distinct material properties of each slab. The methodology generates frequency maps, binary masks, and k-means cluster maps to automatically classify defect and non-defect regions. Key visualizations, including 3D surface plots, cluster maps, and contour plots, are employed to analyze spatial frequency distributions and highlight structural anomalies. The study utilizes a labeled dataset constructed at the Federal Highway Administration (FHWA) Advanced Sensing Technology Nondestructive Evaluation Laboratory. Evaluations involve ground-truth masking, comparing the generated defect maps with top-view binary masks derived from the information provided by the FHWA. The performance metrics, specifically F1-scores and AUC-ROC, achieve values of up to 0.95 and 0.83, respectively. The results demonstrate the robustness of the methodology, consistently identifying defect-prone areas with minimal false positives and few missed defects. Adaptive frequency thresholding ensures flexibility in addressing variations across slabs, providing a scalable framework for detecting structural anomalies. Additionally, the methodology is adaptable to other frequency-based signals due to its generalizable thresholding mechanism and holds potential for integrating multimodal sensor fusion. This automated and scalable pipeline minimizes manual intervention, ensuring accurate and efficient defect detection, further advancing Non-Destructive Evaluation (NDE) techniques.