| Electrical Impedance Tomography (EIT) is an imaging technique that based on the phenomena that the electrical conduction within different kinds of tissue of organism or the same tissue in different states is different. The objective of EIT is to reconstruct the internal conductivity distribution of an object from voltage (or current) measurements made at body surface, by driving with current (or voltage) on its surface. EIT has previously been restricted to the assumption that data originates from a two dimensional (2D) object. In practice, the object is generally a three dimensional (3D) structure, and thus the injected current will flow within the plane of measurement and also through the off-plane volume. This discrepancy leads to images containing significant artefact, impeding analysis and the diagnostic utility of EIT.Three Dimension Electrical Impedance Tomography (3D-EIT) is developing based on the above opinion. In order to obtain more information of tissue, the measurement could be accomplished by scanning in three dimensional.The aim of this work was to design and implement a 3D-EIT system of 64 electrodes, based on physical model of thorax. The main processor TMS320f2812, a kind of Digital Signal Processor, controled the functional modules, such as A/D convertor, LCD display and the communication between the hardware system and PC. The source current module of DDS was ameliorated to meet the need of load. And also the CPLD was introduced into the system to drive the array of channels.
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