Substantial advances in quantitative infrared vision

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Infrared (IR) thermography is an ideal tool for the nondestructive testing of materials. Basically, the observation is carried out either in a passive or active mode. The passive mode consists in using the natural heat developed within the material and observing the temperature distribution as it appears. In the active mode, an external heat source is used to create a thermal perturbation within the material under investigation. Subsequently, an IR imager is used to analyze the thermal wave propagation whose anomalies reveal hidden flaws. An important part of the success of the method is based on how the thermal perturbation (active mode) is transmitted to the material. Another factor that is of paramount importance is image processing (active and passive modes) since it allows the interpretation of the observed phenomena. So far, conventional thermography techniques have encountered several limitations at both the detection and interpretation stages. The proposed research program focuses on investigating new ways of solving the key problems. Our short term objectives will cover the following directions: (1) Investigation of optimal active thermography experiments: the objective is to analyze via theory and experiments the effect of different spatially, and spectrally varying heating modes; the aim is to enhance the detectability of the flaws; (2) Advanced processing methods: methods for solving inverse problems through the state of the art in data compression algorithms such as thermographic signal reconstruction (TSR) or principle component analysis (PCA); planned innovations are for instance into neural networks (NN); (3) Thermophysics for active thermography: the goal is to reliably measure thermal properties of the vast range of new materials subjected to thermal nondestructive tests; thermal properties are required to feed thermal simulation and flaw characterization codes. (4) Design of low-cost inspection systems: the objective is to design low-cost IR thermography setups that might be used by small and medium-size Canadian companies which cannot afford high-end equipment. Powerful built-in processing combined with the new technology of "tiny" uncooled IR cameras will lead to the development of such systems.