Electrical impedance tomography system for body complex impedance / 医疗卫生装备

ABSTRACT

A master-slave electrical impedance tomography (EIT) system for body complex impedance based on digital signal processor (DSP) is designed in this paper. Used as the master computer, a PC performs the image reconstruction and display on time, while DSP carries out such tasks as electrode selection, data acquisition and data communication with the master. Based on DDS technique, the signal generator can create the sine wave signals, and it's amplitude, frequency and phase can be continuously adjusted. The designed feedback unit can improve the linearity and the stability of the voltage-controlled current source effectively. Undersampling technology and digital demodulation technology are used in this system in order to attain the information of real and imaginary components of the body complex impedance. Back projection method is adopted to reconstruct the image in this system. Experimental results show that this system improves the data acquisition speed and the image resolution.