High-precision data acquisition system for electrical impedance imaging

Abstract

The invention discloses a novel high-precision data acquisition system for electrical impedance imaging. The system is constructed by a main control module, a programmable current source, an electrode interface module, a voltage measurement module, a current detection module, a digital demodulation module, a communication interface module and the like. Excitation currents in an imaging target region are accurately controlled through the current detection module and the programmable current source, distribution differences are effectively suppressed through an electrode selection switch system in the electrode interface module, external disturbance is effectively blocked through an electrode wire double-shielding system in the electrode interface module, and related demodulation of response signals and excitation signals is achieved through the digital demodulation module. By the adoption of the high-precision data acquisition system, the influence of distribution parameters and external disturbance in the data acquisition system for electrical impedance imaging can be effectively suppressed, nonlinear errors of a measurement result are reduced, the signal to noise ratio of measured data is increased, the key problem that in the electrical impedance imaging research, data acquisition accuracy is difficultly further improved is solved, and the high-precision data acquisition system has important application value.

Description

technical field [0001] The invention belongs to the technical field of electrical impedance imaging, and relates to an electrical impedance imaging data acquisition technology, in particular to a data acquisition system for electrical impedance imaging. The system realizes the accurate collection of electrical impedance information through the feedback control of the excitation current, the reasonable design of the electrode interface and the accurate demodulation of the measured impedance information, so as to meet the requirements of electrical impedance imaging. Background technique [0002] Electrical impedance imaging technology is based on the fact that different biological tissues have different resistivity characteristics, and changes in pathophysiological functions will also significantly change the characteristics of tissue electrical impedance characteristics. It is a new type of medical imaging technology that uses completely non-invasive alternating current, mea...

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Problems solved by technology

[0006] Aiming at the influence of the shunt effect of distributed parameters on the excitation current, some studies have proposed to connect a negative impedance generator in parallel with the output of the current source to generate negative impedance loads that are equal in size and opposite in direction to these distributed parameters, and neutralize the influence of distributed parameters. However, on the one hand, the negative impedance generator can only be neutralized for a fixed frequency, and it is difficult to adapt to the requirements of the broadband system. On the other hand, it will seriously affect the stability of the system, which will easily lead to the measurement system problem of self-oscillating oscillations, and thus has not been widely accepted

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