Grain Moisture Sensing Using Electrical Capacitance Tomography

Abstract

Electrical Capacitance Tomography (ECT) is a non-destructive electrical imaging method used to visualise dielectric permittivity changes across a cross-section of a sample. This paper explores the effectiveness of ECT for moisture sensing in cereal grains, which plays a crucial role in determining grain quality and the likelihood of spoilage during storage. To achieve accurate and comprehensive insights into moisture distribution, tomography emerges as a promising technique due to its capacity to map larger areas and differentiate moisture variations with precision. Considering related research on the dielectric properties of grain, this paper systemically investigates factors known to affect permittivity. It evaluates ECT's ability to image moisture content relative to these influences. Experiments investigated how a sample's moisture, position, size, temperature, and density affect a sensor's ability to detect moisture changes. To date, limited research has focussed on these influences in the context of cereal grain moisture sensing with ECT. All the tests showed the reconstructions to produce results consistent with existing research concerning the dielectric properties of grain. This study concluded that ECT, utilised with a circular array, effectively distinguished between moisture content in reconstructed images, factors significantly affecting the results. ECT images were disturbed by the position and size of samples within the sampling area. The reconstructed images were also heavily dependent on the sample's bulk density and influenced by different moisture contents within the same sampling area