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Automated Internal Defect Identification and Localization Based on Near-field SAR mmWave Imaging

A revolutionary compact mmWave SAR imaging system with automated defect detection framework achieving 91.7% average accuracy for fast, cost-effective non-destructive testing applications.

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Published: 2025
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IEEE Access
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Accuracy: 91.7%
mmWave NDT
IEEE Access, Volume 11, DOI: 10.1109/ACCESS.2023.1120000
Quoc Cuong Bui, Weizhi Lin, Qiang Huang, Gyung-Su Byun
IEEE - Open Access Engineering Journal

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Abstract

Fast and cost-effective detection of internal defects is essential for structural integrity inspection in various applications in manufacturing, construction, and aerospace. Current internal non-destructive testing (NDT) methods, including computed tomography, are costly, time-consuming and constrained by object size. The lightweight and affordable millimeter wave (mmWave) radar has demonstrated the capability of detecting objects beneath surfaces or obstacles.

This work establishes a robust and automated internal defect detection framework employing a compact mmWave radar system on a stable rail-based scanning mechanism, generating high-resolution near-field SAR images with an enhanced signal-to-noise ratio through denoising. For fast and accurate detection, an automated defect localization algorithm is developed that models and separates internal defects from disturbances introduced by the scanning mechanism.

The proposed method achieved an average accuracy of 91.7%, outperforming existing methods, making it easily integrable into larger scanning systems and adaptable to various object sizes.

Peak Signal-to-Noise Ratio Comparison
Peak Signal-to-Noise Ratio Performance
Comprehensive comparison of PSNR performance between TX1-RX2 and TX3-RX2 transceivers with and without DTCWT denoising across different distances (30mm, 50mm, 100mm), demonstrating significant noise reduction capabilities.
System Overview
Complete mmWave Imaging System Overview
Stabilized high-resolution mmWave imaging system featuring automated defect identification and localization with dual processing paths: scanning & data acquisition and automated defect detection with mathematical modeling.
Hardware Implementation
mmWave Hardware Implementation
Physical implementation showing TX3-RX2 transceiver configuration with AWR1843BOOST and DCA100EVM modules mounted on precision rail scanning mechanism for high-resolution SAR imaging.
3D Printed Test Setup
Experimental Setup & 3D Printed MUT
Complete experimental validation setup featuring 3D printed material under test (MUT) with controlled defects, demonstrating the system's capability to detect various defect shapes, sizes, and depths in real-world scenarios.

Advanced Image Decomposition Algorithm

Process-informed smooth-sparse decomposition (PISSD) methodology for automated defect localization

Image Decomposition Results

Comprehensive image decomposition showing denoised SAR image, detected defects, disturbance background, and noise components - enabling precise defect identification even in challenging scanning conditions.

Breakthrough Performance Results

Revolutionary improvements in non-destructive testing accuracy and efficiency

91.7%
Average Accuracy
Multi-dataset validation
77-81
GHz Frequency
Automotive mmWave band
DTCWT
Denoising Algorithm
Enhanced PSNR
PISSD
Detection Method
Automated localization
3D
Printed MUT
Multi-shape validation
Real-time
Processing
Industrial application

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Key Innovations & Industrial Impact

This research presents a paradigm shift in non-destructive testing technology by introducing a compact, cost-effective mmWave SAR imaging system that dramatically reduces inspection time and costs while maintaining superior accuracy. The integration of automotive-grade mmWave sensors with advanced image processing algorithms creates unprecedented opportunities for real-time quality control in manufacturing environments.

The automated defect detection framework addresses critical industry challenges including operator-induced false identifications, time-consuming manual inspections, and the need for expensive, bulky equipment. By achieving 91.7% average accuracy across multiple test scenarios, this system establishes new benchmarks for internal defect detection in aerospace, construction, and manufacturing applications.

The modular design enables seamless integration into existing production lines, while the automated processing significantly reduces the need for specialized operators, making advanced NDT technology accessible to a broader range of industrial applications and opening new possibilities for in-situ structural health monitoring.