Electrical resistance tomography (ERT) is an imaging technique that determines the internal electrical conductivity of a vessel from measurements taken at its periphery. It is the term used in the industrial process monitoring community for what is know as electrical resistivity tomography in geophysics and electrical impedance tomography in medical imaging. Electrical conductivity is a measure of a materials ability to conduct an electric current. ... Electrical resistivity tomography (ERT) is a geophysical technique for imaging sub-surfaces structures from electrical measurements made at the surface, or by electrodes in bore holes. ... Electrical Impedance Tomography (EIT), is a medical imaging technique in which an image of the conductivity or permittivity of part of the body is inferred from surface electrical measurements. ...

Many electrodes are attached to the vessel's periphery and the ERT system injects a current between a pair of electrodes and measures the resultant voltage difference between remaining electrode pairs according. An image of the three dimensional conductivity is then determined using a numerical solution of an inverse problem. An inverse problem is the task that often occurs in many branches of science and mathematics where the values of some model parameter(s) must be obtained from the observed data. ...

The structure of a typical ERT system is composed of three main parts: sensors, data acquisition system and image reconstruction system/host computer.