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.