Research On Multi-Frequency Hardware System Of Electrical Impedance Tomography Based On DSP Control

Electrical impedance tomography (EIT) is a technique that produces images of the tissues by means of impedance distribution in a body. It is a new imaging technology, which is characteristic of non-invasiveness, cheap, basing on electrical characteristic, succeed other imaging technology.We develop the primary EIT hardware system and design a new multi-frequency hardware system of EIT based on DSP control. The main work is as follows:(1) We adopt a serial modular design of configuration system.(2) We design and complete a multi-frequency source current module, applying the Direct Digital Synthesis (DDS) technology. We use the DSP chip as our controller and the frequency, phase and amplitude of the signal are all programmable and adjustable.(3) We design and complete a excitement and measurement pattern-setting module and a data acquisition module. The DSP is used as the microprocessor. We can use the module collect the excitement result of the multi-frequency current signal accurately.(4) We design a serial communication module between the DSP and the computer. By the module we pass the collected data to the computer for imaging.(5) We use our hardware system measure some object with different conductivity and different porcine tissue such as bone, fat and muscle. By means of back-project algorithm to imaging the physics model, we get actual poison, clear profile.