Electrical capacitance volume tomography (ECVT) is a noninvasive,
3D sensing technology that has proven very successful for imaging and characterization of diverse multi-phase (gas/fluid/solid) flow systems and industrial processes and is also non-destructive. ECVT is a natural spin-off of earlier 2D electrical capacitance tomography (ECT) technology. Because both ECT and ECVT employ an interrogating field that is a solution to Poisson’s equation, they are suitable for a vast range of scales. Indeed, prior applications of ECT have included domains with diameters ranging from tens of microns to meters. As its name suggests, ECVT retrieves volumetric images of the dielectric material distribution on a 3D domain from capacitance measurements taken on its 2D boundary.

The capacitance sensor plates in ECVT are designed to “blanket” the imaging domain with various zones of enhanced (capacitance) sensitivity. The set of all capacitance pairs measured between the plates is sought to react differently to dielectric perturbations on each volumetric “voxel” in the imaging domain. With the aid of image reconstruction algorithms, the differences in the sensor responses are used to establish a volumetric profile, or image, of the dielectric distribution. (Fig. 3-1) However, challenges remain associated with such reconstruction, and Tech4Imaging has been advancing the technology steadily.