Adaptive Broadband Electrical Impedance Tomography for Electrical Spectrum Characterization

Abstract

The invention relates to an adaptive broadband electrical impedance tomography method characterized by electrical spectrum, comprising: using a broadband Chirp signal to excite the measured medium, and selecting a Chirp response with a complete continuous period after the system completes the acquisition of the boundary voltage value Signal, use numerical analysis to analyze the frequency spectrum of the signal to obtain the amplitude-frequency diagram, and then solve the first-order derivative of the amplitude-frequency curve to obtain the sensitive bandwidth interval of the current medium electrical characteristics changing with frequency; select a number of evenly distributed in the sensitive bandwidth interval Single-frequency point, superimposing each specified single-frequency signal into a mixed frequency signal, performing secondary excitation on the measured medium, and completing the acquisition and demodulation of the boundary voltage value, and obtaining the amplitude and phase at each frequency; using the image reconstruction algorithm , to reconstruct the medium distribution image in the measured field. The invention can improve the signal-to-noise ratio of image reconstruction.

Description

Technical field [0001] The present invention belongs to the field of chromatography imaging, and it is related to an adaptive broadband impedance chromatographic imaging method based on biological tissue electrospectral, and obtains the impedance spectrum information and optimal excitation information of biological materials by wide-frequency excitation of the measured medium. , Then mix the mixed excitation to achieve the optimal reconstruction of the distribution of the media measured medium. Background technique [0002] Under the action of the safety excitation current, a certain electrical property is exhibited due to the effects of conductivity and dielectric constant. Various biological tissues have different electrical resistance characteristics, including rich physiological and pathological information. Based on this principle, electrical impingance imaging technology (EIT) is reimbursed by the impedance distribution image within the measured area, and realizes the analy...

AI Technical Summary

Problems solved by technology

Multi-frequency EIT technology adopts two excitation methods: frequency mixing (simultaneous multi-frequency) and frequency sweep (time-division multi-frequency), but the frequency components contained in the two are limited, resulting in the mutual restriction of bandwidth and frequency resolution.

Since the electrical properties of the biological material to be tested are usually unknown, that is, its electrical sensitive bandwidth is uncertain, when it is excited by multiple frequencies, the significant change of electrical properties may happen between two adjacent frequency points, or Outside the bandwidth, the multi-frequency response cannot be measured, which leads to imaging failure or poor effect

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