Portable multi-frequency electrical impedance tomography front-end data acquisition and processing method

Abstract

The invention discloses a portable multi-frequency electrical impedance tomography front-end data acquisition and processing method which comprises the following steps: converting a sinusoidal signal generated by a DAC into a current signal by using a voltage-controlled constant current source, and performing current excitation under the action of a first analog switch; obtaining a reference input signal through a sampling resistor, gating different groups of electrodes through a second analog switch, and performing program control gain by using an inverted T-shaped program control gain amplifier to obtain a measurement input signal; synchronously acquiring the reference input signal and the measurement input signal, performing multiple single-point Fourier demodulation according to the periodicity and symmetry of the digital signal and the symmetry of the trigonometric function, and obtaining the phase information of the signal. The existing demodulation method is improved, the required multiplication frequency is greatly reduced, and the demodulation speed is improved.

Description

technical field [0001] The invention relates to the technical field of electrical impedance imaging, in particular to a portable multi-frequency electrical impedance imaging front-end data collection and processing method. Background technique [0002] Electrical impedance imaging (EIT) includes capacitance imaging (ECT) and electrical resistance imaging (ERT), which is widely used in industrial fields, especially for the detection of multiphase flow, while ERT is oriented to biomedical fields, especially It is various tumor examinations. The measurement method is a non-invasive inspection. The inspection process is as follows: distribute electrode sensors around the biological tissue, inject a safe sinusoidal constant current excitation signal, and the excitation signal will generate an electric field after passing through the biological tissue, while different biological tissues or the same biological The different electrical conductivities of tissues in different physiol...

AI Technical Summary

Problems solved by technology

The main difficulties in the current technology are: due to the large number of electrodes and the large differences in positions, the gain multiples in the detection circuit cannot be unified. At the same time, the number of multiplications required for demodulation when obtaining the amplitude and phase of the detection signal Too much, resulting in reduced demodulation speed

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