Embedded System for Image Reconstruction in Electrical Resistance Tomography

Electrical resistance tomography (ERT) is a method for imaging or retrieving data from an object in a vessel containing electrodes, usually consisting of 8 to 16 electrodes that are enabled to transmit low AC current, resulting in a voltage difference that occurs due to a resistance value on an object. ERT, in its application, requires a long time in the process of data retrieval or excitation of currents. So, this paper is devoted to explaining and reviewing the use of embedded systems for data collection and current excitation processes, where the system uses 8 electrodes as current exciters and 8 electrodes as recipients of different resistance values with the opposite pair drive method. Multiplexers and demultiplexers are used to regulate shifting functions, where all components are controlled using a microcontroller to acquire data with digital to analog conversation or analog to digital conversation capabilities. The principle is to excite the current through the multiplexer, which in this case, requires the help of a relay to excite the current. This is because the multiplexer/de multiplexer component has an internal resistance preventing the current from being excited in the excitation process. An analog-to-digital conversation with a 12-bit resolution is required to capture an object's resistance difference. The results obtained are 48 boundary voltages, which were reconstructed using the Jacobian Gauss-Newton method. This method is quite effective for reconstructing the resistance value into an image, which in this case uses two objects as a comparison material, and there are also sensitivity test results that refer to changes in the voltage value if there is a shift in the object in the vessel containing the electrodes.