Electrical Impedance Tomography With Simultaneous Electrode Excitation
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Solution Overview
Problem
Existing electrical impedance tomography (EIT) methods face limitations in data redundancy, high data complexity, and insufficient image acquisition rates, particularly in high-pressure and high-temperature environments, which are not sufficient for applications requiring rapid image capture, such as monitoring nuclear installations.
Innovation Solution
A method involving simultaneous excitation of multiple electrodes using trigonometric signals and a one-step iterative least-squares reconstruction algorithm to optimize data generation and processing, reducing redundancy and improving image acquisition rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frequency multiplexing with paired electrodes is used to increase data acquisition rate, then image acquisition rate is improved, but data redundancy and measurement complexity increase substantially
Solution Approach 1:
The patent segments the measurement process by selecting only independent electrode pairs for simultaneous excitation, rather than using all possible paired combinations. This segmentation reduces the number of measurements from 120 (in prior art) to a minimal sufficient set, eliminating redundancy while maintaining the ability to reconstruct the impedance map at high acquisition rates
Solution Approach 2:
The patent extracts and eliminates redundant measurements from the dataset by carefully selecting only the independent electrode pairs needed for reconstruction. This extraction process removes unnecessary data generation steps, reducing hardware complexity and computational burden while preserving the essential information needed for image reconstruction
2Productivity
If multiple simultaneous excitation signals are applied to increase acquisition rate, then data acquisition speed is improved, but the bandwidth requirement increases
Solution Approach 1:
The patent employs periodic excitation signals with carefully selected frequencies that are harmonically related. By using periodic signals with frequencies fm = m*f0 where f0 is a fundamental frequency, the system achieves high acquisition rates while keeping the total bandwidth requirement manageable through frequency reuse and harmonic relationships
3Loss of information
If paired electrode excitation is used to obtain comprehensive data, then measurement coverage is improved, but data optimization for inverse problem solution deteriorates
Solution Approach 1:
The patent applies local quality by assigning specific excitation patterns to specific electrode pairs based on their spatial relationships. Each selected electrode pair receives excitation signals tailored to its position and function in the reconstruction process, optimizing the data quality for inverse problem solution rather than applying uniform excitation to all pairs
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves significantly higher image acquisition rates and optimizes data processing, enabling real-time monitoring of fluid flows with reduced data size and complexity, suitable for applications like nuclear reactor pipe monitoring.
Implementation Method 1
Electrical impedance tomography (EIT) is a non-invasive, non-destructive technique that allows an image of the interior of an object to be generated, in real time and continuously, by measuring electrical properties (electrical current and potential) of the surface of the object
Implementation Method 2
It is known to implement time-division multiplexing whereby an excitation signal is applied to a single pair of electrodes at a time. The various pairs of electrodes are selected sequentially by means of multiplexers or electronic switches
Implementation Method 3
Frequency multiplexing allows a superposition of simultaneously injected signals to be generated, this permitting higher data acquisition rates
Implementation Method 4
simultaneously exciting each of the ne electrodes, each electrode being excited by a potential Vnexc having the form: Vnexc(t)=A*Σ(m=1 to ne-1) cos(2π*fm*t+θn+m*π/ne) where fm=m*f0 is an oscillation frequency
Data Source
AI summary
An electrical impedance tomography method for the measurement of a body comprising a cylindrical part containing a fluid, the method comprising arranging a number of electrodes around a periphery of the cylindrical part of the body, simultaneously exciting each of the electrodes, each electrode being excited by a potential of a selected form, measuring the electrical properties of the body using electrodes, and processing the data from measuring step so as to obtain a signed data matrix representative of an image.