Feasibility of Pulsed Thermography for Moisture Estimation

Abstract

The dehydration of farm products provides farmers an opportunity to preserve their products longer and simultaneously earn more profit from them. Nevertheless, traditionally the quality of the dehydrated products has been determined by the use of invasive methods, for example, through manual measurements with a Vernier caliper and a micrometer, has its greatest weakness in the monitoring of continuous production lines and, that is why an efficient methodology is often required for estimating the moisture in dehydrated products. The goal of this study was to explore the feasibility of pulsed thermography for estimating the moisture content of farm products in the drying process. In this paper, a methodology to estimate dehydration in real-time was developed and the design and construction of a real-time pulsed thermographic imaging system were described. Moreover, to demonstrate the principle of the operation, Neem (Azadirachta indica) leaves were used in a dehydration process. The specimen was submitted to a heat pulse, and its reaction through time was observed by an infrared camera, then, the sequence of captured images generates a characteristic curve. That curve relates the moisture content with the response to the heat pulse. The results demonstrated the efficiency of the pulsed thermography in differentiating the percentage of dehydration in Neem leaves.