Terahertz Defect Detection in Multi-Layer Materials Using Echo Labeling

TL;DR

This paper introduces a novel terahertz time-domain spectroscopy method for non-destructive defect detection in multi-layer materials, leveraging echo labeling and Euclidean distance matrices to improve defect localization accuracy and reduce complexity.

Contribution

It presents a new approach inspired by acoustic geometry estimation, using Euclidean distance matrices to enhance defect detection in multi-layer composites with high-power THz sources.

Findings

Effective defect localization without artifacts

Reduced problem complexity compared to existing methods

Enhanced detection of higher-order reflections

Abstract

Non-destructive testing is an important technique for detecting defects in multi-layer materials, enabling the evaluation of structural integrity without causing damage on test materials. Terahertz time-domain spectroscopy (THz-TDS) offers unique capabilities for this purpose due to its sensitivity and resolution. Inspired by room geometry estimation methods in acoustic signal processing, this work proposes a novel approach for defect detection in multi-layer composite materials using THz-TDS, enhanced by high-power sources. The proposed method utilizes Euclidean distance matrices to reduce problem complexity compared to state-of-the-art approaches, and effectively distinguishes and maps higher-order reflections from sublayers, enabling precise defect localization in composite materials without artifacts.