In this paper is presented an IR imaging technique allowing one to retrieve quantitative concentration and temperature maps with relatively fast acquisition times of samples evolving in time. A model study is realized based on the drying of a drop of colloidal dispersion in confined geometry and quantitative maps of colloid volume fraction and temperature everywhere in the dorp are retrieved. Finally, a secondary technique of IR tomography is presented to extend the setup sensitivity to the thickness of the sample and 3D tomographs of both thermal emissivity and IR absorbance of a silica gel are constructed numerically.
We present a methodology to measure the in-plane thermal diffusivity of (an)isotropic samples using flying spot thermography. We obtain an analytical expression for the surface temperature distribution when a continuous wave laser spot scans the sample surface at constant velocity. By analyzing this expression, we propose three simple methods to measure the thermal diffusivity in the directions parallel and perpendicular to the motion. The methodology can also be applied in the case where the laser spot is at rest, and the specimen moves at constant velocity. This configuration is interesting for in-line evaluation of industrial products. Finally, we present a set-up allowing the inspection of large and complex parts, by means of a robotic arm used to displace the part and orient the region of interest perpendicular to the optical axis of the camera.
The first imaging system that is able to measure transient temperature phenomena taking place inside a bulk by 3D tomography is presented. This novel technique combines the power of terahertz waves and the high sensitivity of infrared imaging. The tomography reconstruction is achieved by the 3D motion of the sample at several angular positions followed by inverse Radon transform processing to retrieve the 3D transient temperatures. The aim of this novel volumetric imaging technique is to locate defects within the whole target body as well as to measure the temperature in the whole volume of the target. This new-fashioned thermal tomography will revolutionize the non-invasive monitoring techniques for volume inspection and <i>in-situ</i> properties estimations.