CN109745046B - Electrical impedance imaging electrode and system suitable for motion state - Google Patents
Electrical impedance imaging electrode and system suitable for motion state Download PDFInfo
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- CN109745046B CN109745046B CN201910057540.6A CN201910057540A CN109745046B CN 109745046 B CN109745046 B CN 109745046B CN 201910057540 A CN201910057540 A CN 201910057540A CN 109745046 B CN109745046 B CN 109745046B
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Abstract
The invention discloses an electrical impedance imaging electrode and a system suitable for a motion state, which comprises a test electrode module, a signal gating device, a test signal generator, a controller, a test signal collector and an information processor, wherein the signal gating device is used for gating a signal; the testing electrode module is connected with the signal gating device through the testing data line, the signal gating device is connected with the testing signal generator through the excitation bus, the signal gating device is connected with the controller through the control bus, the signal gating device is connected with the testing signal collector through the collection bus, the resistance value of the flexible fiber piezoresistive material can change along with the change of pressure and distortion degree, the change conditions of the positions and other states of the electrodes prepared by the flexible fiber piezoresistive material can be monitored by monitoring the change of the resistance value of the flexible fiber piezoresistive material, the flexible fiber piezoresistive material is easy to prepare, good in conductivity and adaptive to pressure, and the sensitivity of. The invention designs a set of time sequence measurement process at the same time, which is used for simultaneously realizing the acquisition of the impedance information of the field to be measured required by the EIT technology and the acquisition of the complementary electrode distortion state information in the EIT system.
Description
Technical Field
The invention relates to a design scheme of an Electrical Impedance Tomography (EIT) system, in particular to an Electrical Impedance imaging electrode and a system suitable for a motion state.
Background
The Electrical Impedance Tomography (EIT) is a new medical imaging technology with the advantages of functional imaging, no damage, no radiation, low cost, high imaging speed and the like. The EIT can embody the physiological and pathological information of human tissues by functional imaging. The concept of bioelectrical impedance imaging was first proposed in 1978 by John g. David c.barber and Brian h.brown were the first to develop the application of EIT to human conductivity distribution measurements. In the decades since then, EIT has become one of the hot areas of current scientific research as a medical imaging technology with attractive application prospects. At present, the EIT technology has made great progress in theory, hardware design, and image reconstruction, and there have been many studies aiming at specific clinical application points: lung respiration monitoring imaging, abdominal organ function imaging, breast cancer detection imaging and brain detection imaging.
In the current research process of the EIT technology for human organs, the current research work mainly focuses on the image reconstruction technology and the extraction and analysis technology of organ bioelectric signals, however, the electrode is one of the core components of the whole system, and is finally used as a key problem to be solved in the production process of the whole system and the application of clinical medical instruments, but the previous scientific research does not obtain enough attention of researchers of the electrical impedance imaging technology, and the related research is not deep enough. At present, in the application research of the electrical impedance tomography technology in the medical field, Ag/AgCl electrodes are mostly adopted as exciting and measuring electrodes. A typical Ag/AgCl electrode application process was introduced in 2015, ZhouWei et al, biomedical electrode manufacturing technology and application research progress published in scientific bulletin, 15 th, 1352-1360. First, a trained person is required to remove the stratum corneum and clean the skin according to where each electrode is placed, and then to stick the electrodes to the skin surface via a conductive gel. The conductive gel is easy to dehydrate and dry, so that the electrode is easy to fall off, and the electrical impedance characteristic of the conductive gel is changed. The electrode of the type is not suitable for long-term use, the electrode can be in poor contact with the skin, the current distribution is not uniform, and the acquired electrical impedance signals are easy to generate abnormal fluctuation to influence the final image result.
Biomedical electrodes, as a key sensing device for connecting EIT data acquisition and processing platforms and human bodies, typically require multiple electrodes to excite and measure bioelectrical signals. In addition, compared with biological imaging technologies such as CT, nuclear magnetic resonance and the like, the advantages of nondestructive, nonradiative and low-cost EIT technology also make the EIT technology more valuable in the application of long-term monitoring of organisms. Therefore, the electrodes used in EIT should also be comfortable enough to wear for long periods of time and not require the patient to remain in a fixed position during the measurement. EIT typically requires multiple electrodes to excite and measure bioelectrical signals, and the use of multiple electrodes can involve the problem of how the electrodes are distributed, and how to overcome the interference caused by movement during the measurement process. In this year, some research around this aspect is also being conducted, such as: contact pressure and flexibility of a multi-needle dry electroencephalogram electrode (Contact pressure and flexibility of multi-needle dry electroencephalogram electrodes) published in chapter 1-1 of IEEE Transactions on Neural Systems and Rehabilitation Engineering (IEEE Transactions on Neural Systems & Rehabilitation Engineering) by Fieder P et al in 2018 proposes a multi-needle dry electrode for electroencephalogram monitoring, and research results of the multi-needle dry electrode and the multi-needle dry electrode find that the quality of a measurement signal depends on stable Contact between the electrode and the skin. They studied the relationship of pressure to contact impedance by applying pressure, and monitored the contact impedance of the electrode to the skin using a pressure sensor integrated on the electrode. The design of the electrode can monitor the contact condition of the electrode and the surface of a living body to a certain extent, but the structure is relatively complex, and the function is single.
Disclosure of Invention
In order to solve the technical problems, the invention provides a test electrode of an EIT system based on a flexible fiber piezoresistive material, and designs a set of EIT improved test system aiming at a novel multifunctional multiplexing electrode, which is used for monitoring the deformation and distortion measurement of the flexible electrode and fusing the flexible electrode with imaging data to improve the imaging quality under the condition of organism motion.
An electrical impedance imaging electrode and a system suitable for a motion state comprise a testing electrode module, a signal gating device, a testing signal generator, a programmable controller, a testing signal collector and an information processor; the testing electrode module is connected with the signal gating device through a testing data line, the signal gating device is connected with the testing signal generator through an excitation bus, is connected with the programmable controller through a control bus, is connected with the testing signal collector through an acquisition bus, distributes bus signals to the testing electrode module, and the testing signal collector is connected with the information processor through a data bus.
The testing electrode module comprises electrodes which are made of flexible piezoresistive materials and are arranged in a tight mode.
And an elastic connecting section between the electrodes is also included, and preferably, the ratio of the length of the electrodes to the length of the elastic connecting belt is more than 3: 1.
The electrode connection mode is as follows: the piezoresistive variable signal testing device comprises a conductive body and a data measuring line, wherein the conductive body 1 is provided with an electrode, the data measuring line is connected with the electrode, the data measuring line comprises excitation signal lines Ya and Xa used for testing piezoresistive variable signals, data acquisition signal lines Yb and Xb used for testing the piezoresistive variable signals, a test excitation signal line A used for testing field resistance and used for testing impedance information of EIT imaging, and a test acquisition signal line B used for testing field resistance and used for testing impedance information of EIT imaging.
The data measuring lines on the electrodes are connected with the signal gating device and are controlled by the programmable controller to be gated by the test generator and the test signal collector. The signal gating device is divided into six modules, namely a multi-path gating device Xa, a multi-path gating device Xb, a multi-path gating device Ya, a multi-path gating device Yb, a multi-path gating device A and a multi-path gating device B, and the six modules are respectively used for managing signal connection of 6 data test lines. The multi-channel gates Xa, Ya are controlled by CtrXa and Ctrya signals of the programmable controller respectively, and the Xa, Ya signal lines of the electrodes and the piezoresistive material test signals of the test generator are gated or grounded (reference level) in different test time of the test period. The multi-channel gates Xb and Yb are respectively controlled by CtrXb and CtrYb signals of the programmable controller, and signal lines Xb and Yb of each electrode and a piezoresistive material acquisition module for signal test are gated or grounded (reference level) in different test time of a test period. The multi-way gate A, B is controlled by signals CtrA and CtrB of the programmable controller respectively, and gates the signal line A of each electrode and the impedance imaging measurement signal of the test generator. And the signal line B is gated with the impedance imaging data acquisition module of the test signal.
A method for carrying out electrical impedance imaging by an electrical impedance imaging system based on piezoresistive electrodes comprises the following steps:
(1) inputting the number of test electrodes, determining a test period, and starting measurement;
(2) and (3) electrode testing: the system enters a 1 st electrode monitoring period, in the period, the programmable controller controls the multi-channel gates Xa, Ya gating 1Xa and 1Ya and the piezoresistive signal test source through CtrXa and Ctrya, controls the multi-channel gates Xb and Yb gating 1Xb and 1Yb and the piezoresistive signal collector through CtrXb and CtrYb, and input and output channels of other multi-channel gates are in a suspended state;
(3) and (3) impedance information measurement: the system enters a 1 st impedance information measurement period, in the period, the programmable controller controls the multi-channel gating devices Xa, Ya, Xb and Yb to gate 2Xa, 2Ya, 2Xb and 2Yb to be grounded (gating reference electrodes) through CtrXa, Ctrya, CtrXb and CtrYb, controls the multi-channel gating device A to gate 1A and the impedance test signal generator through CtrA, controls any two electrode combinations of the gating device gating 3B-numB channel to be communicated with the impedance signal collector through CtrA, and suspends the other channels;
(4) and (3) electrode testing: after the system enters the ith electrode monitoring period, the remainder of dividing i by N is obtained as number, N is the product of the number of the measuring electrodes, which is number and the number of the smooth period, in the period, the programmable controller controls the multi-channel gate to gate the piezoresistive signal test sources of the number Xa, the number ya and the test generator through CtrXa and Ctrya, controls the multi-channel gate to gate the piezoresistive signal collectors of the number Xb, the number Yb and the test signal collector through CtrXb and CtrYb, and the input and output channels of other multi-channel gates are in a suspended state;
(5) and (3) impedance information measurement: in the period, a programmable controller controls multiple-channel gates Xa, Ya, Xb and Yb to be grounded (gating reference electrodes) through CtrXa, Ctrya, CtrXb and CtrYb, controls a gate 1A and an impedance test signal generator through CtrA, controls any two electrode combinations of a channel B and a channel B to be communicated with an impedance signal collector through CtrA, and suspends the other channels.
(6) And judging whether the number of the test cycles is an integral multiple of the number of num × k, if so, inputting the piezoresistive signals and the impedance measurement signals into an information processor, and performing fusion imaging on data of the collector, otherwise, entering the next electrode monitoring cycle and the impedance information measurement cycle.
Further comprising the step (7): and a state classifier in the information processor classifies the acquired piezoresistive signals, calls a sensitivity matrix at a corresponding position, and forms a sensitivity matrix for displaying an imaging result together with the EIT test information matrix.
And monitoring an electrode falling failure signal by the state classifier, sending out warning information to the corresponding electrode serial number, and otherwise, continuing to enter the cycle of the measurement period.
Before the step (1), the method also comprises the step of uniformly arranging the test electrodes around the field to be tested according to the condition of the boundary of the field to be tested; the process of entering testing then begins.
The information processor tests the input piezoresistive signals, classifies the piezoresistive signals by the state classifier, obtains a sensitivity matrix according to a data set of the sensitivity matrix, obtains an EIT test information matrix by testing the input EIT test signals, and obtains a radian matrix displaying an imaging result through the sensitivity matrix and the EIT test information matrix.
The state classifier classifies the piezoresistive signals in the simulation calculation of the upper computer, and the piezoresistive signals are obtained through principal component weight analysis of the piezoresistive signals at different electrode positions and cluster analysis of the weighted multi-electrode piezoresistive signals and the piezoresistive signals at different electrode placement positions;
the data set of the sensitivity matrix is obtained through finite simulation calculation of different positions of the electrodes in the simulation calculation of the upper computer.
Compared with the prior art, the invention has the advantages that:
the general ET electrode adopts a common good conductor material (such as Ag-AgCl for medical electrodes), and the invention adopts a flexible fiber piezoresistive material as a preparation material of the electrode. The flexible fiber piezoresistive material has the conductive characteristic of a general good conductor, in addition, the resistance value can be changed along with the change of the pressure and the distortion degree of the flexible fiber piezoresistive material, the change conditions of the positions and other states of the electrodes prepared by the flexible fiber piezoresistive material can be monitored by monitoring the change of the resistance value, the flexible fiber piezoresistive material is easy to prepare, good in conductivity, adaptive to the pressure and high in sensitivity of distortion change. The resistance value change is monitored in the test, and the distortion change of the electrode is judged according to the resistance value change. The invention designs a set of time sequence measurement process at the same time, which is used for simultaneously realizing the acquisition of the impedance information of the field to be measured required by the EIT technology and the acquisition of the complementary electrode distortion state information in the EIT system. Through the measurement of the conductivity of the flexible piezoresistive electrodes, the distortion state information of the flexible electrodes is quantified and supplemented into an imaging algorithm, and the imaging quality is improved.
Drawings
FIG. 1 is a schematic diagram of an electrical impedance imaging electrode and system suitable for use in motion in accordance with the present invention;
FIG. 2 is a schematic diagram of the shape of an electrode made of flexible piezoresistive material according to the present invention;
FIG. 3 is a schematic diagram of an electrode arrangement of the EIT testing system of the present invention;
FIG. 4 is a schematic diagram of a signal strobe, a test signal generator, a test signal collector and an information processor according to the present invention;
fig. 5 is a functional block diagram of an information processor according to the present invention.
FIG. 6 is a flow chart of the EIT testing system of the present invention.
Detailed Description
The present invention is further illustrated by the following examples, but is not limited to the specific embodiments.
As shown in fig. 1, the electrical impedance imaging electrode and system suitable for use in a motion state of the present invention is an electrical impedance imaging test system based on flexible piezoresistive electrodes, and includes a test electrode module, a signal gating device, a test signal generator, a programmable controller, a test signal collector, and an information processor. The test electrode module is connected with the signal gating device through a test data line. The signal gating device is connected with the test signal generator through an excitation bus, connected with the programmable controller through a control bus, connected with the test signal collector through a collection bus and distributes bus signals to the test electrode modules. The test signal collector is connected with the information processor through a data bus.
The respective modules are explained in detail below.
In the test electrode module, an electrode made of flexible piezoresistive material is shown in fig. 2, wherein 1 is a conductor, 2 is an electrode made of flexible piezoresistive material, the conductor 1 is sewn on the piezoresistive material 2 for better contact with the piezoresistive material and sensitive to resistance signals changing along with the change of the flexible electrode, and 3 is a series of data measurement lines, wherein signal lines Ya and Xa are excitation signal lines for testing piezoresistive change signals, signal lines Yb and Xb are data acquisition lines for testing piezoresistive change signals, a signal line a is a test excitation signal line for testing field resistance and impedance information for EIT imaging, and a signal line B is a test acquisition signal line for testing field resistance and impedance information for EIT imaging.
As shown in fig. 3, taking an eight-electrode EIT testing system as an example, the arrangement of the electrodes of the present invention includes electrodes and elastic connecting sections between the electrodes, wherein the electrodes are arranged in a compact manner, the ratio of the length of the electrodes to the length of the elastic connecting sections is above 3:1, and the electrodes can fully sense the force applied to the electrodes when the electrodes are in a tight-bound state due to a certain change in position in two directions.
As shown in fig. 4, in the present invention, an EIT system with 8 electrodes is taken as an example, and 6 data lines on each electrode are connected to a signal strobe device, and are controlled by a programmable controller and gated by a test generator and a test signal collector. The signal gating device is divided into six modules, namely a multi-path gating device Xa, a multi-path gating device Xb, a multi-path gating device Ya, a multi-path gating device Yb, a multi-path gating device A and a multi-path gating device B, and the six modules are respectively used for managing signal connection of 6 data test lines. The multi-channel gates Xa, Ya are controlled by CtrXa and Ctrya command signals of the programmable controller respectively, and gate the signal lines Xa, Ya of the 8 electrodes and the piezoresistive material test signal of the test generator or are grounded (reference level) in different test time of the test period. The multi-channel gates Xb and Yb are controlled by CtrXb and CtrYb command signals of the programmable controller respectively, and signal lines Xb and Yb of 8 electrodes and the piezoresistive signal collector of the test signal collector are gated or grounded (reference level) in different test time of a test period. The multiplexer A, B is controlled by signals CtrA and CtrB of programmable controller respectively, and gates the signal lines A of 8 electrodes and the impedance test signal generator of the test generator. The signal line B is gated with the impedance signal collector of the test signal collector.
As shown in the test flow charts of fig. 5 and 6, the specific imaging mode of the system is as follows:
first, for the case of the field boundary to be tested, the test electrodes are uniformly arranged around the field to be tested. The process of entering testing then begins.
Inputting the number of test electrodes, determining a test period and starting measurement;
and secondly, the system enters a 1 st electrode monitoring period, during the period, the CtrXa and Ctrya can be programmed to control the multi-channel gates Xa, Ya to gate the 1Xa and 1Ya and the piezoresistive test signal generator, the CtrXb and CtrYb can be programmed to control the multi-channel gates Xb and Yb to gate the 1Xb and 1Yb and the piezoresistive signal collector, and input and output channels of other multi-channel gates are in a suspended state. And after the system enters the ith electrode monitoring period, setting number as the remainder of dividing i by N, in the period, controlling the multi-channel gates Xa, Ya, gating number Xa, number Ya and the piezoresistive test signal generator of the test generator by the programmable controller through CtrXa and Ctrya, controlling the piezoresistive signal collectors of the multi-channel gates Xb, Yb gating number Xb, number Yb and the piezoresistive signal collector of the test signal collector through CtrXb and CtrYb, and enabling the input and output channels of other multi-channel gates to be in a suspended state.
And thirdly, the system enters a 1 st impedance information measurement period, in the period, the programmable controller controls the multi-channel gates Xa, Ya, Xb and Yb to be grounded (gating reference electrodes) through CtrXa, Ctrya, CtrXb and CtrYb, controls the gating 1A and the impedance test signal generator through CtrA, controls any two electrode combinations of the gating 3B-8B channels to be connected with the impedance signal collector through CtA, and suspends the other channels. And in the period, the programmable controller controls the multi-channel gates Xa, Ya, Xb and Yb to gate (number +1) Xa, (number +1) Ya, (number +1) Xb and (number +1) Yb to be grounded (gating reference electrodes) through CtrXa, Ctrya, CtrXb and CtrYb, controls the multi-channel gate A to gate 1A and the impedance test signal generator through CtrA, controls any two electrode combinations of the channels B and B to be communicated with the impedance signal collector through CtrA, and suspends the other channels.
And fourthly, judging whether the number of the test cycles is integral multiple of the number of the electrodes or not, if so, carrying out fusion imaging on the data of the test signal collector, and if not, entering the next electrode monitoring period and impedance information measuring period.
And fifthly, judging whether the measuring times reach a preset smooth period value k, and inputting the piezoresistive signals and the impedance measuring signals into the information processor.
And sixthly, classifying the acquired piezoresistive signals by a state classifier in the information processor, and calling a sensitivity matrix at a corresponding position to participate in the imaging process of the currently obtained impedance information matrix. And monitoring an electrode falling failure signal by the state classifier, sending out warning information to the corresponding electrode serial number, and otherwise, continuing to enter the cycle of the measurement period.
The present invention also provides a method of imaging by testing an input piezoresistive signal and an input EIT test signal, as shown in fig. 5, where g is a grayscale imaging matrix of size N (N ═ a × b), and λ represents a one-dimensional vector of M orders of the test information of the EIT system (M is the total number of electrode combinations tested in one test cycle), which is continuously updated according to the measurement result of the test signal of each EIT. S is a preset normalized sensitivity matrix of the standard field, the size of which is (M × N), and it reflects the potential change that can be caused by the unit conductivity change on each pixel, and the calculation formula of S is:
in the formula, I and j represent the serial numbers of the measuring electrodes, x and y represent the positions of pixel points of an imaged picture, Si and j (x and y) represent the mapping of the information of the I and j measuring electrodes to the imaging points x and y, p represents a function of the positions x and y of the pixel points of the imaged picture, E represents the voltage measured at the electrodes, and I represents the exciting current at the electrodes.
Then g, S and λ are associated as follows:
λ＝S·g
in the invention, the generation method of the sensitivity matrix S is obtained by using a finite element simulation method, and the obtained sensitivity matrix has a direct relation with the position of the electrode. And meanwhile, carrying out cluster analysis on piezoresistive signal matrixes corresponding to different electrode positions and piezoresistive signals generated by specific movement, judging the specific form of the piezoresistive signals of each position signal, establishing a correlation set, and inputting the correlation set into a state classifier. In the testing process, the state classifier carries out electrode position classification on the acquired piezoresistive signals and calls a data set of a corresponding sensitivity matrix to participate in imaging.
In order to improve the quality of cluster analysis, noise information in the test process is prevented from influencing classification. And (3) carrying out principal component analysis and dimensionality reduction on the signal, wherein the steps of carrying out principal component analysis and dimensionality reduction on the signal are as follows:
1. the piezoresistive information signals output by electrodes attached to the surface of a biological body under the environment of several typical medical electrodes are tested, n samples are measured, and each sample is composed of voltage test signals with p ═ num × 2 dimensions (num is the number of tested electrodes) and forms a matrix X in the following form:
the above formula is subjected to standardized data processing, and the standardized processing formula is as follows:
wherein
Is the arithmetic mean of the values of Xj,
is the standard deviation of Xj. And let Z ═ n × p (zij) be the data matrix after normalization.
2. Computing covariance matrices for normalized data
In the variable X ═ X1X2 … Xp, the correlation coefficient calculation formula for both variables is:
since the variables in Z are already normalized variables, the covariance matrix of the column variables of Z is now the correlation coefficient matrix.
3. Computing the feature root and feature vector of R
The characteristic equation of the correlation matrix R is | R- λ I | ═ 0, the characteristic root λ I (j ═ 1,2, … p) of the matrix R can be obtained by using the characteristic equation, the characteristic roots are arranged from small to large, the corresponding characteristic vectors γ I ═ (γ I1, γ I2, … γ ip)', the component values of the characteristic vectors are used as weights, and the standardized indexes are weighted to obtain principal component weights.
4. Calculating the variance contribution rate of the weight and the principal component
The size of the characteristic root of the correlation matrix R reflects the proportion of information contained in the ith principal component, and the contribution rate is as follows:
5. setting cumulative contribution rate
|akAnd | represents that Ak is arranged from large to small, a component of principal component analysis with Ak reaching 90% is selected, and m corresponding electrode targets are determined.
The steps of performing cluster analysis on the signals are as follows:
1. testing aggregated data
According to the principal component analysis, the positions of the electrode sets entering the principal component are correspondingly enumerated, each combination is named as Yi, Yi ═ Y1, Y2, … ym ], so that a cluster Y ═ Y1, Y2 … Yt is formed, and as the analysis set performed in the principal component analysis, a piezoresistive signal set X of several typical actions is taken as a set to be classified.
2. Classification similarity measurement criterion of signal similarity
x (n) is the signal component of the actual signal of a particular dimension, and y (n) is the piezoresistive signal of the electrode location set. And judging the similarity between Yi and X according to rho ij, setting a threshold value of rho ij, and counting the number q of X components with the similarity higher than rho ij to serve as an availability criterion of Yi.
3. And setting an availability criterion Q, and taking the electrode position of Q > Q as a sensitivity matrix simulation object.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by the present specification, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (4)
1. A method for carrying out electrical impedance imaging by utilizing an electrical impedance imaging test system suitable for a motion state is characterized in that the electrical impedance imaging test system suitable for the motion state comprises a test electrode module, a signal gating device, a test signal generator, a programmable controller, a test signal collector and an information processor; the testing electrode module is connected with a signal gating device through a testing data line, the signal gating device is connected with a testing signal generator through an excitation bus, is connected with a programmable controller through a control bus, is connected with a testing signal collector through an acquisition bus, distributes bus signals to the testing electrode module, the testing signal collector is connected with an information processor through a data bus, the testing signal collector comprises a piezoresistive signal collector and an impedance signal collector, and the testing signal generator comprises a piezoresistive testing signal generator and an impedance testing signal generator;
the testing electrode module comprises an electrode, a conductor and a data measuring line, wherein the electrode is made of flexible piezoresistive material; the electrode connection mode is as follows: the conductor and the data measuring line are connected with the electrode, the data measuring line comprises an excitation signal line Ya and an excitation signal line Xa for testing the piezoresistive change signals, a data acquisition signal line Yb and a data acquisition signal line Xb for testing the piezoresistive change signals, a test excitation signal line A for testing the field resistance and impedance information used for EIT imaging, a test acquisition signal line B for testing the field resistance and impedance information used for EIT imaging,
the data measuring lines on each electrode are connected with the signal gating device and are controlled by the programmable controller to be gated by the test signal generator and the test signal collector; the signal gating device is divided into six modules, namely a multi-path gating device Xa, a multi-path gating device Xb, a multi-path gating device Ya, a multi-path gating device Yb, a multi-path gating device A and a multi-path gating device B, and the six modules are used for respectively managing signal connection of 6 data measuring lines; the multi-channel gate Xa and the multi-channel gate Ya are respectively controlled by CtrXa instruction signals and Ctrya instruction signals of the programmable controller, the excitation signal line Xa of each electrode is gated in different testing time of a testing period, and the excitation signal line Ya and a piezoresistance testing signal generator of the testing signal generator are grounded; the multi-channel gate Xb and the multi-channel gate Yb are respectively controlled by CtrXb instruction signals and CtrYb instruction signals of the programmable controller, and data acquisition signal lines Xb of all electrodes are gated in different testing time of a testing period, and the data acquisition signal lines Yb and a piezoresistive signal collector of the testing signal collector are grounded; the multi-channel gate A and the multi-channel gate B are respectively controlled by a CtrA instruction signal and a CtrB instruction signal of a programmable controller, and the test excitation signal line A of each electrode and the impedance test signal generator of the test signal generator are gated; the test acquisition signal line B is gated with the impedance signal acquisition device of the test signal acquisition device;
the specific steps of the electrical impedance imaging method are as follows:
(1) inputting the number of test electrodes, determining a test period, and starting measurement;
(2) and (3) electrode testing: the system enters a 1 st electrode monitoring period, in the period, the programmable controller controls the excitation signal lines Xa and Ya of the multi-channel gate Xa and Ya gating 1 st test electrode and the piezoresistive test signal generator through CtrXa and Ctrya, controls the multi-channel gate Xb and Yb through CtrXb and CtrYb to gate the data acquisition signal lines Xb and Yb and the piezoresistive signal collector of the 1 st test electrode, and the input and output channels of other multi-channel gates are in a suspended state;
(3) and (3) impedance information measurement: the system enters a 1 st impedance information measuring period, in the period, a programmable controller controls multi-channel gates Xa, Ya, Xb and Yb to gate excitation signal lines Xa, Ya of a 2 nd test electrode and data acquisition signal lines Xb and Yb of a 2 nd test electrode to be grounded through CtrXa, Ctrya, CtrYb, controls a multi-channel gate A to gate a test excitation signal line A of the 1 st test electrode and an impedance test signal generator through CtrA, controls a multi-channel gate B to gate any two electrode combinations of a test acquisition signal line B of a 3 rd test electrode and a test acquisition signal line B of a num test electrode through CtrA to be communicated with an impedance signal collector, and suspends other channels;
(4) and (3) electrode testing: after the system enters an ith electrode monitoring period, the number of i divided by N is obtained, N is the product of the number of the measuring electrodes num and the number of the smooth period k, in the period, a programmable controller controls multi-channel gates Xa and Ya to gate excitation signal lines Xa and Ya of a number testing electrode and a piezoresistive testing signal generator of the testing signal generator through CtrXa and Ctrya, controls multi-channel gates Xb and Yb to gate data acquisition signal lines Xb and Yb of the number testing electrode and the piezoresistive signal collector of the testing signal collector through CtrXb and CtrYb, and input and output channels of other multi-channel gates are in a suspended state;
(5) and (3) impedance information measurement: in the period, a programmable controller controls a multi-channel gate Xa, Ya, Xb and Yb to gate an excitation signal line Xa, Ya of a (number +1) th test electrode and a data acquisition signal line Xb and Yb of a (number +1) th test electrode to be grounded through CtrXa, Ctrya, CtrXb and CtrYb, controls a multi-channel gate A to gate a test excitation signal line A of the 1 st test electrode and an impedance test signal generator through CtrA, controls a multi-channel gate B to gate any two electrode combinations of a test acquisition signal line B except the number test electrode and a test acquisition signal line B of the (number +1) th test electrode to be connected with an impedance signal collector through CtrA, and suspends the rest channels;
(6) judging whether the number of the test cycles is an integral multiple of N num x k, if so, inputting the piezoresistive signals and the impedance measurement signals into an information processor, and performing fusion imaging on data of the test signal collector, and if not, entering the next electrode monitoring cycle and the impedance information measurement cycle;
(7) the state classifier in the information processor classifies the acquired piezoresistive signals, calls the sensitivity matrix of the corresponding position, and forms a sensitivity matrix for displaying an imaging result together with the EIT test information matrix, and specifically comprises the following steps:
the information processor tests input piezoresistive signals, then a state classifier in the information processor classifies the electrode positions of the acquired piezoresistive signals, obtains a sensitivity matrix according to a data set of the sensitivity matrix, obtains an EIT test information matrix by testing the input EIT test signals, and obtains a gray matrix displaying an imaging result through the sensitivity matrix and the EIT test information matrix;
the state classifier classifies the electrode positions of the piezoresistive signals in the simulation calculation of the upper computer, and the piezoresistive signals are obtained through principal component weight analysis of the piezoresistive signals of the electrodes at different positions and cluster analysis of the weighted multi-electrode piezoresistive signals and the piezoresistive signals at different electrode placement positions;
the data set of the sensitivity matrix is obtained through finite simulation calculation of different positions of the electrodes in the simulation calculation of the upper computer.
2. A method of electrical impedance imaging using an electrical impedance imaging testing system adapted for use in motion according to claim 1, wherein the arrangement of electrodes includes electrodes and resilient connecting sections between the electrodes, the ratio of the length of the electrodes to the length of the resilient connecting sections being greater than 3: 1.
3. An electrical impedance imaging method using an electrical impedance imaging test system suitable for use in a moving state as claimed in claim 2, wherein the state classifier monitors the electrode fall-off failure signal and sends out warning information for the corresponding electrode serial number, otherwise the cycle of the measurement period is continued.
4. An electrical impedance imaging method using an electrical impedance imaging test system suitable for a moving state according to any one of claims 2-3, wherein before inputting the number of test electrodes, determining a test period and starting measurement, the method further comprises arranging the test electrodes uniformly around the field to be measured for the case of the boundary of the field to be measured; the process of entering testing then begins.
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