Low-Cost Lock-In-Thermography System for Educational Use

We present a cost-efficient lock-in thermography platform built from an industrial OEM micro-bolometer and LED excitation, aimed at teaching laboratories and budget-constrained NDT. The system is benchmarked against a scientific-grade thermal imager on three specimens: (i) a carbon-fiber composite plate with impact-induced delamination, (ii) a PVC flat-bottom-hole phantom with controlled diameter and remaining wall thickness, and (iii) a PVC double-hole feature from literature. Identical preprocessing and FFT-based demodulation are used for both systems; complementary 3D time-domain simulations (COMSOL) support interpretation. Across 0.01–1 Hz, the low-cost setup reproduces defect morphology and phase trends observed with the reference, including frequency-dependent phase behavior consistent with thermal-wave depth sensitivity. Quantitatively, phase contrast is lower for the low-cost system and approaches the detection limit at higher modulation frequencies, as expected from diffusion-length scaling. The strongest agreement is in phase, with amplitude discrepancies attributable to excitation non-uniformity and simplified loss modeling. We conclude that the platform is well suited for education and shows promise for targeted industrial screening with modest hardware and processing upgrades.     «

We present a cost-efficient lock-in thermography platform built from an industrial OEM micro-bolometer and LED excitation, aimed at teaching laboratories and budget-constrained NDT. The system is benchmarked against a scientific-grade thermal imager on three specimens: (i) a carbon-fiber composite plate with impact-induced delamination, (ii) a PVC flat-bottom-hole phantom with controlled diameter and remaining wall thickness, and (iii) a PVC double-hole feature from literature. Identical preproc...     »