Measurement-based thermal modeling using laser thermography

There have been several studies in using infrared thermography for nondestructive evaluation and testing of materials. Some studies have explored the potential of using thermography for classification of materials based on their thermal response. However, the modeling behind these efforts is rather simplistic, and in some ways not corresponding well with practical applications. This paper presents a realistic model-based approach for characterizing unknown materials using laser thermography. The process being modeled is laser excitation step thermography with finite but not infinitesimal excitation length and uniform distribution over a finite radius. A mathematical model, based on the heat equation that governs the flow of heat in materials, is introduced to characterize objects based on their response to thermal excitation. Experimental results consistently demonstrated the ability of the proposed approach to classify different materials based on their thermal properties. This contactless characterization method might prove to be suitable for a range of applications including teleoperation, haptic mapping and multimodal human computer interaction.