Thermophysical properties mapping in semi-infinite longitudinally cracked plates by temperature image processing

Abstract

Thermophysical properties mapping in a solid plate from transient temperature imaging analysis is widely developed, but most usual methods are based on very restrictive assumptions such as the independence of the pixels (local one-dimensional diffusion in the sample). The challenge envisioned in this study is to take into account the three-dimensional spatial correlation between pixels. Moreover, the estimation of the thermophysical properties field from two-dimensional measurements is an ill-posed problem, and the practical implementation of the estimation is affected by the large amount of data to be processed. A semi-numerical analysis with spatially random front face excitation is proposed here in order to overcome such problems. A theoretical new method is proposed for the detection of cracks laid perpendicular to the excitation surface. The estimation method is implemented from a spatial autoregressive method.

Keywords:

• Infrared image processing
• Thermal diffusivity mapping
• Random heat flux
• Autoregressive estimation

Acknowledgments

The authors gratefully acknowledge the support of the Department of Regional Cooperation in the South Cone and Brasil at the French Embassy in Chile.