US 12,468,059 B2
Method of measuring by electrical impedance tomography
Mathieu Darnajou, Pertuis (FR); and Guillaume Ricciardi, Le Tholonet (FR)
Assigned to COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES, Paris (FR)
Appl. No. 18/551,338
Filed by COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES, Paris (FR)
PCT Filed Mar. 25, 2022, PCT No. PCT/EP2022/057897
§ 371(c)(1), (2) Date Sep. 19, 2023,
PCT Pub. No. WO2022/200558, PCT Pub. Date Sep. 29, 2022.
Claims priority of application No. 2103099 (FR), filed on Mar. 26, 2021.
Prior Publication US 2024/0184010 A1, Jun. 6, 2024
Int. Cl. G01V 3/06 (2006.01)
CPC G01V 3/06 (2013.01) 7 Claims
OG exemplary drawing
 
1. An electrical-impedance-tomography measuring method of a body comprising a cylindrical portion containing a fluid, the method comprising:
arranging a number ne of electrodes around a periphery of the cylindrical portion of the body,
simultaneously exciting each of the ne electrodes, each electrode being excited by a potential Vnexc having a form:

OG Complex Work Unit Math
where A is a signal amplitude, θn is an angular position of electrode n, fm=m*f0 is an oscillation frequency, f0 is a fundamental frequency chosen such that fm is less than a Nyquist frequency of the system for all m, δ is the Kronecker delta, and
custom character={2k+1:k∈custom character} is the set of odd integers
custom character={2k:k∈custom character*} is the set of non-zero even integers,
measuring electrical properties Vnmeas of the body using the electrodes, and
processing data generated in the measuring step, by:
a) for each electrode En, computing data points Mn defined by:

OG Complex Work Unit Math
where R is a resistance of a resistor used to measure Vnmeas with Vnmeas=R In across terminals of the resistor, P is a number of points in a discrete sequence of measurement of the current In, p is a discrete time, k is a Fourier coefficient comprised between 1 and (ne−1) and βp=(2πp/P),
b) constructing a data matrix D from the data points Mn(k) for all n and for all k, according to the equation:

OG Complex Work Unit Math
and
c) constructing a signed data matrix, the elements of which are defined by the following equation when a phase shift Φn,l(k) between an excitation potential at electrode 1 and a current measured at electrode n is less than π/2:

OG Complex Work Unit Math
and the elements of which are defined by the following equation when the phase shift Φn,l(k) between the excitation potential at electrode 1 and the current measured at electrode n is greater than or equal to π/2:
Dnm=ΣnmDnm
where Σ is a sign matrix defined such that an i-th element of a j-th row of Σ is the sign of cosine ([2π/([j 1]/2)]*(i−1)/ne) for odd j and a sign of sine ([2π/(j/2)]*(i−1)/ne) for even j.