MATHEMATICS, SIMULATION AND MODELLING
5 March 2009
Dynaflow's DynaEIT is a suite of efficient algorithms for solving Electrical Impedance Tomography (EIT) problems. EIT seeks to image the interior of a container based on variation of electrical properties. Using the boundary element method, DynaEIT provides an accurate and efficient set of algorithms for identification of the container contents.
In EIT the distribution of conductivity inside a container is sought by applying specified currents (or voltages) at portions of the container surface and performing measurements of the voltage (or currents) at other locations along the surface. The equations for the electric field then provide relationships between the conductivity distribution inside the domain and the measured voltages and currents. Different types of materials have different conductivities resulting in a conductivity map that provides an image of the material distribution in the container.
CPU-efficient methods, such as a Dipole Approximation method, and a Singular Boundary Element Method are used to rapidly solve the 'forward' problem of determination of voltage and current distributions for a known conductivity distribution in the imaged domain in two and three dimensions. The inverse problem is the problem of image reconstruction using the measured voltages and/or currents. This is solved by application of multi-dimensional minimisation procedures, such as Powell's Direction Set Method, the Downhill Simplex Method, Genetic Algorithms, and multi-objective minimisation based on Pareto sets.
These EIT algorithms can be applied to medical imaging, multiphase flows encountered in chemical, oil and gas, energy, and aerospace industries, non-destructive evaluation of structures and materials, imaging of underground water paths and container leakage, archaeology, detection of buried objects, chemical reactive flows, and many others.