Indirect determination of moisture using biospeckle technique

Abstract

The classification and selection of agricultural products are very important to assure post-harvest quality processes. However, most of physical and chemical analyses are destructive. It means those products turn useless after these analyses. Moisture is one of the most important parameters to assure the storage quality and as well to facilitate product processing. This research offers an alternative method to determine that parameter through an indirect and non-destructive way, using the image analysis based on the Biospeckle phenomenon. This method consists in get a 10 seconds video of a laser focused on the object. This video is divided in frames, using a computational routine in Matlab and, then, the sequence of images is processed using the computational program named ImageJ. The results are expressed in terms of modified correlation matrix and Moment of Inertia (MI). At the same time, a moisture analysis is carried out using the traditional methodology employing conventional heater equipment set at 130 ºC. By correlating MI and moisture values, it was possible to determine the moisture content by means of an indirect method. To this research, it was employed grains of Moringa oleifera.