Practical design of low-cost instrumentation for industrial electrical impedance tomography (EIT)

Electrical Impedance Tomography (EIT), is one of the medical imaging technologies. It can also be used in industrial process monitoring. In this method, the image of the electrical conductivity distribution of the inner part of a conductive subject can be reconstructed. The image reconstruction process is done by injecting an accurate current into the boundary of a conductive subject (e.g. body), measuring the voltages around the boundary and transmitting them to a computer, and processing on acquired data with a software (e.g., MATLAB). The images are obtained from the peripheral data by using an algorithm. Precise EIT instrumentation plays an important role in the final images quality. In this paper, we have proposed a practical design of low-cost precise EIT hardware, containing a high output impedance current source with a pulse generation part and also an accurate voltage demodulator and measurement part. All the subsystems have been tested accurately. By using this structure, electrical impedance tomography have been implemented successfully. The quality of reconstructed images, confirms the accuracy of the proposed EIT hardware.