A hybrid pulsed thermography processing technique for the depth estimation of subsurface defects combining TSR and PPT
نویسنده
چکیده
A hybrid approach, combining thermographic signal reconstruction (TSR) and pulsed phase thermography (PPT), is proposed and tested for the depth estimation of subsurface defects from pulsed thermographic data. First, TSR is used to obtain the polynomial coefficients from raw data. A synthetic thermogram sequence is then reconstructed from the obtained coefficients. Finally, quantitative PPT is applied to this sequence for defect depth estimation purposes. This combined procedure allows to considerably reduce signal noise, improving depth estimation results as a consequence. A TSR module has been added to an existent graphical user interface (ir_view) to perform these operations.
منابع مشابه
Quantitative Subsurface Defect Evaluation by Pulsed Phase Thermography : Depth Retrieval with the Phase
Pulsed Phase Thermography (PPT) is a NonDestructive Testing and Evaluation (NDT&E) technique based on the Fourier Transform that can be thought as being the link between Pulsed Thermography, for which data acquisition is fast and simple; and Lock-In thermography, for which depth retrieval is straightforward. A new depth inversion technique using the phase obtained by PPT is proposed. The techni...
متن کاملInformation condensation in defect detection using TSR coefficients images
The Thermographic Signal Reconstruction (TSR) technique, based on the logarithmic polynomial fitting of the temperature time-evolution, improves the efficiency of pulse-stimulated thermography. However, the non-destructive evaluation of the inspected structure requires the analysis of the full temperature-time sequence. This drawback impacts all transient thermal NDE method whatsoever. A new po...
متن کاملNon-destructive Evaluation of Composites Materials by Pulsed-phase Thermography: Depth Inversion
This work is focused in the application of Pulsed-Phase Thermography (PPT) to non-destructive evaluation of composite materials. In this approach, the composite sample is heated by a thermal pulse briefly and recording the surface temperature decay with an infrared camera. Data processing and depth inversion is carried out by extracting and analyzing the response of the sample on the frequency ...
متن کاملComparative study of thermographic signal reconstruction and partial least squares thermography for the detection and evaluation of subsurface defects
Thermographic signal reconstruction (TSR) and partial least squares thermography (PLST) are techniques conceived for the processing and analysis of pulsed thermography (PT) data. In this work, the capabilities of both techniques are evaluated. A thermal data sequence was obtained from a PT inspection on a carbon fiber reinforced polymer (CFRP) specimen with simulated delaminations (Teflon inser...
متن کاملSubsurface defect characterization in artworks by quantitative PPT
In this study, experimental thermographic data from a specimen fresco with fabricated inserts was acquired and processed by Pulsed Phase Thermography (PPT) to detect and characterize the subsurface defects. The well-known concept of Signal-to-Noise Ratio (SNR) is proposed for the selection of the proper phasegram frequency at which defect sizing is performed. Different filtering techniques are ...
متن کامل