CN117547243A - EIT imaging equipment and contact impedance acquisition method and device thereof - Google Patents
EIT imaging equipment and contact impedance acquisition method and device thereof Download PDFInfo
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- 230000005284 excitation Effects 0.000 claims abstract description 338
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- 238000002347 injection Methods 0.000 claims description 7
- 239000007924 injection Substances 0.000 claims description 7
- 238000004590 computer program Methods 0.000 claims description 5
- 238000012790 confirmation Methods 0.000 claims description 5
- 238000002593 electrical impedance tomography Methods 0.000 description 57
- 238000005259 measurement Methods 0.000 description 10
- 238000010586 diagram Methods 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
- A61B5/053—Measuring electrical impedance or conductance of a portion of the body
- A61B5/0536—Impedance imaging, e.g. by tomography
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
Abstract
The application provides a contact impedance acquisition method of an EIT imaging device, wherein the EIT imaging device comprises a plurality of electrodes, and the method comprises the following steps: sequentially identifying each excitation electrode pair and all corresponding non-excitation electrode pairs from the plurality of electrodes; exciting each exciting electrode pair by using a preset exciting current, and sensing the exciting voltage of the corresponding non-exciting electrode pair to obtain the current exciting voltage of each exciting electrode pair; taking the current excitation voltage with the minimum value in the current excitation voltage of each excitation electrode pair as the excitation voltage of the reference electrode pair; according to the excitation voltage and the preset excitation current, calculating the contact impedance of the odd excitation electrode and the even excitation electrode of the reference electrode pair to obtain reference contact impedance; and respectively calculating the contact impedance of each excitation electrode in the remaining excitation electrode pairs according to the reference contact impedance and the remaining current excitation voltage. In addition, the application also provides a contact impedance acquisition device of the EIT imaging device and the EIT imaging device.
Description
Technical Field
The application relates to the technical field of electrical impedance tomography, in particular to EIT imaging equipment and a contact impedance acquisition method and device thereof.
Background
Bioelectrical impedance tomography (Electrical Impedance Tomography, EIT) is a type of non-invasive medical imaging that detects impedance image distribution within a target tissue by applying a safe current signal to the surface of the measured target tissue while measuring a voltage signal at the surface of the target tissue. In the prior art, the contact impedance at the electrode can be generally calculated by directly measuring the voltage between the excitation of the constant current source, so as to estimate the contact impedance at the positive electrode and further judge the contact condition of the electrode. However, this approach provides insufficient accuracy in the measured contact resistance when the electrode contact is inaccurate.
Disclosure of Invention
The application provides EIT imaging equipment and a contact impedance acquisition method and device thereof, excitation voltages of other electrode pairs are measured through excitation formed by adjacent electrode pairs, contact impedance of each electrode is determined according to excitation current, and safety of a contact impedance acquisition process is improved through measurement of a plurality of electrodes while the contact impedance is accurately calculated.
In a first aspect, an embodiment of the present application provides a method for acquiring contact impedance of an EIT imaging apparatus, where the EIT imaging apparatus includes a plurality of electrodes, the method for acquiring contact impedance of the EIT imaging apparatus includes: sequentially identifying from the plurality of electrodes each excitation electrode pair, and all non-excitation electrode pairs under each excitation electrode pair, each excitation electrode pair comprising an odd excitation electrode and an even excitation electrode; exciting each exciting electrode pair by using a preset exciting current, and sensing the exciting voltage of the corresponding non-exciting electrode pair to obtain the current exciting voltage of each exciting electrode pair; taking the current excitation voltage with the minimum value in the current excitation voltage of each excitation electrode pair as the excitation voltage of the reference electrode pair; according to the excitation voltage of the reference electrode pair and the preset excitation current, calculating the contact impedance of the odd excitation electrode and the even excitation electrode of the reference electrode pair to obtain an odd reference contact impedance and an even reference contact impedance; and respectively calculating the contact impedance of each excitation electrode in the residual excitation electrode pair according to the odd reference contact impedance, the even reference contact impedance and the residual current excitation voltage, wherein the odd reference contact impedance is used for calculating the contact impedance of the odd excitation electrode of the residual excitation electrode pair, and the even reference contact impedance is used for calculating the contact impedance of the even excitation electrode of the residual excitation electrode pair.
In a second aspect, an embodiment of the present application provides a contact impedance acquiring apparatus of an EIT imaging device, where the EIT imaging device includes a plurality of electrodes, the contact impedance acquiring apparatus of the EIT imaging device includes an injection module, an acquisition module, a confirmation module, and an impedance calculation module, where the injection module is configured to sequentially confirm each excitation electrode pair and all non-excitation electrode pairs under each excitation electrode pair, where each excitation electrode pair includes an odd excitation electrode and an even excitation electrode; the acquisition module is used for exciting each exciting electrode pair by using a preset exciting current and sensing the exciting voltage of the corresponding non-exciting electrode pair to obtain the current exciting voltage of each exciting electrode pair; the confirmation module is used for taking the current excitation voltage with the minimum value in the current excitation voltage of each excitation electrode pair as the excitation voltage of the reference electrode pair; the impedance calculation module is used for calculating the contact impedance of the odd excitation electrode and the even excitation electrode of the reference electrode pair according to the excitation voltage of the reference electrode pair and the preset excitation current to obtain an odd reference contact impedance and an even reference contact impedance, and respectively calculating the contact impedance of each excitation electrode of the remaining excitation electrode pair according to the odd reference contact impedance, the even reference contact impedance and the remaining current excitation voltage, wherein the odd reference contact impedance is used for calculating the contact impedance of the odd excitation electrode of the remaining excitation electrode pair, and the even reference contact impedance is used for calculating the contact impedance of the even excitation electrode of the remaining excitation electrode pair.
In a third aspect, an embodiment of the present application provides an EIT imaging apparatus, including a plurality of electrodes, the EIT imaging apparatus further including a memory for storing a computer program, and a processor; the processor is configured to execute the computer program to implement the contact impedance acquiring method of the EIT imaging apparatus.
According to the EIT imaging equipment and the contact impedance obtaining method and device thereof, the confirmed different electrode pairs are used as the excitation electrode pairs to excite the excitation electrode pairs by using the preset excitation current, the excitation voltage of the non-excitation electrode pairs is sensed to obtain the current excitation voltage of the excitation electrode pairs, the minimum current excitation voltage is confirmed to serve as the reference voltage, and the reference contact impedance is further determined, so that the contact impedance of each excitation electrode in the remaining excitation electrode pairs is determined according to the reference contact impedance and the residual current excitation voltage, the contact impedance of each excitation electrode in the excitation electrode pairs is calculated to obtain the contact impedance of the odd excitation electrode and the even excitation electrode respectively, and the calculation accuracy of the electrode contact impedance is improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained from the structures shown in these drawings without inventive effort to a person of ordinary skill in the art.
Fig. 1 is a flowchart of a contact impedance obtaining method of an EIT imaging apparatus provided in an embodiment of the present application.
Fig. 2 is a flowchart of a substep of step S105 provided in an embodiment of the present application.
Fig. 3 is a schematic structural diagram of a contact impedance acquiring device of an EIT imaging apparatus according to an embodiment of the present application.
Fig. 4 is a schematic diagram of an internal structure of an EIT imaging apparatus to which a contact impedance obtaining method of the EIT imaging apparatus is applied according to an embodiment of the present application.
Fig. 5 is a schematic structural diagram of an EIT imaging apparatus provided in an embodiment of the present application.
Fig. 6 is a schematic diagram of a calculation model of contact impedance according to an embodiment of the present application.
The realization, functional characteristics and advantages of the present application will be further described with reference to the embodiments, referring to the attached drawings.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.
The terms "first," "second," "third," "fourth" and the like in the description and in the claims of this application and in the above-described figures, if any, are used for distinguishing between similar elements of a plan and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged under appropriate circumstances, or in other words, the described embodiments may be implemented in other sequences than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, may also include other items, such as processes, methods, systems, articles, or apparatus that include a series of steps or elements, are not necessarily limited to only those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such processes, methods, articles, or apparatus.
It should be noted that the description herein of "first," "second," etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implying an indication of the number of technical features being indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be regarded as not exist and not within the protection scope of the present application.
Please refer to fig. 1, which is a flowchart of a contact impedance obtaining method of an EIT imaging apparatus according to an embodiment of the present application. The embodiment of the application provides a contact impedance acquisition method of EIT imaging equipment. Bioelectrical impedance tomography (Electrical Impedance Tomography, EIT) is a type of non-invasive medical imaging by applying a safe excitation current signal or excitation voltage signal to the surface of the measured target tissue while measuring the voltage signal or current signal at the surface of the target tissue, and from the measured signals, obtaining the impedance distribution within the tissue under examination using an image reconstruction algorithm. The object to be measured may be a human body, for example a patient, i.e. the excitation current signal or the excitation voltage signal is a safe excitation for the human body. According to the contact impedance obtaining method of the EIT imaging equipment, the corresponding current excitation voltage is obtained through excitation by confirming the different electrode pairs as the excitation electrode pairs, and then the contact impedance of each excitation electrode is calculated. The EIT imaging equipment comprises a plurality of electrodes, and the electrodes are arranged in sequence. The contact impedance acquiring method of the EIT imaging apparatus includes steps S101 to S105.
Step S101, sequentially identifying each excitation electrode pair and all non-excitation electrode pairs under each excitation electrode pair from the plurality of electrodes.
In step S101, each excitation electrode pair includes an odd excitation electrode and an even excitation electrode. The non-excitation electrode pair is an electrode pair that does not include any of the corresponding excitation electrodes of the excitation electrode pair. Specifically, when the EIT imaging device is used for measurement, a pair of electrodes are used as excitation electrodes, and the rest electrodes are used as measurement electrodes for switching measurement; and then taking the other pair of electrodes as an excitation electrode pair, and performing switching measurement on the rest electrodes as measurement electrode pairs, wherein the cycle is performed until all the electrodes are taken as the excitation electrode pairs to finish the corresponding measurement electrode pairs, namely finishing one measurement.
Please refer to fig. 5, which is a schematic diagram of the structure of the EIT imaging apparatus according to the embodiment of the present application.
As shown in fig. 5, EIT imaging apparatus 100 includes excitation module 101, and hardware component 102. Wherein the excitation module 101 is provided with a port IP103 and a port IN104 for providing a constant current source, and a switch matrix 105 for switching different electrodes. The currents at port IP103 and port IN104 are equal IN magnitude and opposite IN direction. The EIT imaging apparatus 100 can cause a constant magnitude of current to flow between any two electrodes by switching the switch matrix 105. For example, when the port IP103 turns on the electrode 1 and the port IN104 turns on the electrode 2, a constant current is conducted between the electrode 1 and the electrode 2.
Step S102, exciting each exciting electrode pair by using a preset exciting current, and sensing the exciting voltage of the corresponding non-exciting electrode pair to obtain the current exciting voltage of each exciting electrode pair.
In step S102, the loop formed by each pair of excitation electrodes and each pair of non-excitation electrodes is regarded as one measurement channel. In this embodiment, the non-excitation electrode pair is an electrode pair that does not include any one of the excitation electrode pair. For example, when EIT imaging apparatus 100 is a 16-electrode apparatus, its corresponding number of measurement channels is 16×13=208. For one excitation electrode pair, the number of non-excitation electrode pairs under the EIT imaging apparatus 100 of 16 electrodes is 16-1-2=13. After the excitation voltages of the remaining 13 excitation electrode pairs are obtained, the current excitation voltage of the excitation electrode pair can be obtained by the excitation voltages of the 13 excitation electrode pairs, i.e., the current excitation voltage is the sum of the excitation voltages of all non-excitation electrode pairs corresponding to each excitation electrode pair.
In this embodiment, the sum of the current excitation voltages, which is the excitation voltage of the corresponding non-excitation electrode pairs, is calculated by sequentially identifying each excitation electrode pair and all non-excitation electrode pairs under each excitation electrode pair from a plurality of electrodes according to the adjacent injection method.
It will be appreciated that for pairs of excitation electrodes, the excitation voltage of each non-excitation electrode pair may be measured one by one, or the excitation voltages of all non-excitation electrode pairs may be calculated simultaneously in a parallel manner. Similarly, for each electrode pair, the current excitation voltage corresponding to each electrode pair serving as the excitation electrode pair can be obtained one by one, or all electrode pairs serving as the current excitation voltages corresponding to the excitation electrode pair can be calculated simultaneously in a parallel mode.
In this embodiment, after calculating the present excitation voltage of one excitation electrode pair, the next excitation electrode pair may be determined by switching of the switch matrix 105 so that a constant magnitude of current flows between the two electrodes of the next excitation electrode pair after the next excitation electrode pair is confirmed.
Step S103, taking the current excitation voltage with the smallest numerical value in the current excitation voltages of each excitation electrode pair as the excitation voltage of the reference electrode pair.
Step S104, according to the excitation voltage and the preset excitation current of the reference electrode pair, calculating the contact impedance of the odd excitation electrode and the even excitation electrode of the reference electrode pair to obtain the odd reference contact impedance and the even reference contact impedance.
In step S104, the odd reference contact impedance and the even reference contact impedance are equal. The calculation formula of the odd reference contact impedance and the even reference contact impedance is as follows: r is R odd_tar ＝R even_tar ＝U min /(2I), where R odd_tar Represents an odd reference contact resistance, R even_tar Represents even reference contact impedance, U min Representing the current excitation voltage with the smallest value, and I represents the preset excitation current.
Please refer to fig. 6, which is a schematic diagram of a calculation model of contact impedance according to an embodiment of the present application.
As shown in fig. 6, for one excitation electrode pair, the load of EIT imaging apparatus 100 can be regarded as three impedance series at this time, i.e., the excitation electrode pair is connected in series with the human body impedance. The calculation formula of the load is r=r 1 +R 2 +R load Wherein R represents a load, R 1 Represents contact resistance 1, R 2 Represents contact resistance 2, R load Representing the impedance of the human body.
It will be appreciated that since the power supply is a constant current source, the potential difference U measured between port IP103 and port IN104 is proportional to the load R, as known from ohm's law u=r×i. Where U represents the measured voltage signal, i.e. the current excitation voltage, i.e. the potential difference between port IP103 and port IN 104. For the same patient, the human body impedance R load And contact resistance R 1 And R is 2 Irrespective, it can be considered as a stable value, and therefore, the load R and the contact resistance R of the EIT imaging apparatus 100 1 And R is 2 And (5) correlation. When the electrode contact becomes worse, the contact resistance of the electrode will rise, and the corresponding load R will also rise, thereby increasing the current excitation voltage U. Therefore, in order to determine the relative magnitude of the contact impedance of each electrode, the present application further simplifies the calculation model, and considers the contact impedance of the two electrodes on the pair of excitation electrodes with the best contact condition to be equal, namely, the contact impedance of the two electrodes of the target electrode pair corresponding to the smallest current excitation voltage is confirmed to be equal.
In this embodiment, the calculation formula of the target contact impedance is: r is R tar ＝U min I, wherein R is tar Representing the target contact impedance, U min Representing the minimum present excitation voltage, I representing the preset excitation current.
With continued reference to fig. 5, the hardware component 102 is, in order, a signal difference module 106, a digital-to-analog converter (Analog to Digital Converter, ADC) driver 107, and an ADC module 108. The ADC is a component that can sample an analog signal to obtain a digital signal. The signal difference module 106 is configured to perform subtraction of the voltage of the port IP103 and the voltage of the port IN 104. The signal difference module 106 may be a component that implements voltage subtraction, such as a subtractor or an instrumentation operational amplifier. After the voltage difference between the port IP103 and the port IN104 is obtained, the voltage signal is processed, that is, the current excitation voltage is sequentially input to the ADC driver 107 and the ADC block 108. The ADC driver 107 is configured to increase the sampling accuracy of the ADC and perform data processing such as amplification, attenuation, and filtering on the voltage signal. The ADC module 108 is configured to perform analog-to-digital conversion to sample the voltage signal, obtain a digital signal, and perform an operation on the digital signal by the main control end of the EIT imaging apparatus 100, so as to calculate the contact impedance of each electrode.
Step S105, calculating the contact impedance of each excitation electrode in the remaining excitation electrode pairs based on the odd reference contact impedance, the even reference contact impedance, and the remaining current excitation voltage.
In step S105, the odd reference contact impedance is used to calculate the contact impedance of the odd excitation electrodes of the remaining excitation electrode pair, and the even reference contact impedance is used to calculate the contact impedance of the even excitation electrodes of the remaining excitation electrode pair.
Please refer to fig. 2 in combination, which is a flowchart of the substep of step S105 provided in the embodiment of the present application. The calculation of the contact impedance of each excitation electrode in the remaining excitation electrode pairs from the odd reference contact impedance, the even reference contact impedance, and the remaining current excitation voltage, respectively, includes steps S1051-S1052.
Step S1051, extracting the current excitation voltage of the other excitation electrode pair including the odd excitation electrode of the reference electrode pair to obtain the excitation voltage of the odd excitation electrode pair, and extracting the current excitation voltage of the other excitation electrode pair including the even excitation electrode of the reference electrode pair to obtain the excitation voltage of the even excitation electrode pair.
Step S1052, calculating the contact impedance of the odd excitation electrode of the other excitation electrode pair by using the excitation voltage of the odd excitation electrode pair, the preset excitation current and the odd reference contact impedance, and calculating the contact impedance of the even excitation electrode of the other excitation electrode pair by using the excitation voltage of the even excitation electrode pair, the preset excitation current and the even reference contact impedance.
In this embodiment, the calculation formula of the contact impedance of the odd excitation electrode is: r is R odd -R odd+2 ＝(U odd -U odd+1 ) 2, odd=2k+1, k=0, 1,2 … …, where odd represents the order of the odd excitation electrodes, R odd And R is odd+2 Represents the contact impedance of the odd-numbered excitation electrodes, U odd Representing the corresponding current excitation voltage when the odd excitation electrode is the excitation electrode of the smaller order of the excitation electrode pairs.
In this embodiment, the calculation formula of the contact impedance of the even excitation electrode is: r is R even -R even+2 ＝(U even -U even+1 ) 2, even=2k, k=1, 2 … …, where even denotes the order of even excitation electrodes, R even And R is even+2 Represents the contact impedance of even excitation electrodes, U even Representing the corresponding current excitation voltage when an even number of excitation electrodes are used as the smaller-order excitation electrode in the excitation electrode pair.
It will be appreciated that before calculating the contact impedance of each odd excitation electrode and each even excitation electrode, the contact impedance of the other excitation electrode in the excitation electrode pair that does not include each other, corresponding to the odd reference contact impedance and the even reference contact impedance, respectively, needs to be calculated by the reference contact impedance. For example, in the 16-electrode apparatus, the current excitation voltage corresponding to the formation of the excitation electrode pair by the electrodes 1 and 2 is the smallest after sensing the excitation voltage, and before calculating the contact impedances of the remaining electrodes 3, 4 … …, it is necessary to calculate the contact impedances of the other excitation electrode in the excitation electrode pair, that is, the contact impedances of the electrodes 16 and 3, of the electrodes 1 and 2, which do not include each other, by the electrodes 1 and 2, respectively, and further calculate the contact impedances of the electrodes 5, 7 … …, 15, and the electrodes 4, 6 … …, 14 according to the calculation formulas of the contact impedances of the odd excitation electrodes and the contact impedances of the even excitation electrodes in the above embodiments, respectively.
Please refer to fig. 3, which is a schematic diagram of a contact impedance acquiring device of an EIT imaging apparatus according to an embodiment of the present application.
As shown in fig. 3, the embodiment of the present application further provides a contact impedance obtaining device 11 of the EIT imaging apparatus. The EIT imaging apparatus comprises several electrodes. The contact impedance acquiring apparatus 11 of the EIT imaging device includes an injection module 110, an acquisition module 111, a confirmation module 112, and an impedance calculation module 113.
The injection module 110 is configured to sequentially identify each excitation electrode pair, and all non-excitation electrode pairs under each excitation electrode pair, from a plurality of electrodes, each excitation electrode pair including an odd excitation electrode and an even excitation electrode.
The acquisition module 111 is configured to excite each excitation electrode pair by using a preset excitation current, and sense an excitation voltage of a corresponding non-excitation electrode pair to obtain a current excitation voltage of each excitation electrode pair.
The confirmation module 112 is configured to take the current excitation voltage with the smallest value in the current excitation voltages of each excitation electrode pair as the excitation voltage of the reference electrode pair.
The impedance calculating module 113 is configured to calculate, according to an excitation voltage of the reference electrode pair and a preset excitation current, contact impedances of odd excitation electrodes and even excitation electrodes of the reference electrode pair to obtain an odd reference contact impedance and an even reference contact impedance, and calculate, according to the odd reference contact impedance, the even reference contact impedance, and a remaining current excitation voltage, contact impedances of each excitation electrode of the remaining excitation electrode pair, where the odd reference contact impedance is used to calculate contact impedances of the odd excitation electrodes of the remaining excitation electrode pair, and the even reference contact impedance is used to calculate contact impedances of the even excitation electrodes of the remaining excitation electrode pair.
Referring to fig. 4, an internal structure diagram of an EIT imaging apparatus to which the contact impedance obtaining method of the EIT imaging apparatus is applied according to an embodiment of the present application is shown.
As shown in fig. 4, the present embodiment also provides an EIT imaging apparatus 100 including a plurality of electrodes. EIT imaging apparatus 100 further includes a memory 901 and a processor 902. The processor 902 is configured to execute computer program instructions in the memory 901 to implement a method for acquiring contact impedance of an EIT imaging apparatus. In the present embodiment, the specific structure of the EIT imaging apparatus 100 can also refer to the above-described embodiments. Since the EIT imaging apparatus 100 adopts all the technical solutions of all the embodiments, at least all the beneficial effects brought by the technical solutions of the embodiments are provided, and will not be described in detail herein.
The memory 901 includes at least one type of readable storage medium including flash memory, a hard disk, a multimedia card, a card type memory (e.g., SD or DX memory, etc.), magnetic memory, magnetic disk, optical disk, etc. Memory 901 may be an internal storage unit of a computer device in some embodiments, such as a hard disk of a computer device. The memory 901 may also be a storage device of an external computer device in other embodiments, for example, a plug-in hard disk configured in the computer device, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), and so on. Further, the memory 901 may also include both internal storage units and external storage devices of the computer device. The memory 901 may be used not only for storing application software installed in a computer device and various types of data, such as a code of a contact resistance acquisition method of an EIT imaging device, but also for temporarily storing data that has been output or is to be output.
Further, EIT imaging apparatus 100 further includes bus 903. Bus 903 may be a peripheral component interconnect standard (peripheral component interconnect, PCI) bus or an extended industry standard architecture (extended industry standard architecture, EISA) bus, among others. The bus may be classified as an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is shown in fig. 4, but not only one bus or one type of bus.
Further, EIT imaging apparatus 100 may further comprise a display assembly 904. The display component 904 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, an Organic Light-Emitting Diode (OLED) touch device, or the like. Among other things, the display component 904 may also be referred to as a display device or display unit, as appropriate, for displaying information processed in the EIT imaging apparatus 100 and for displaying a visual user interface.
Further, EIT imaging apparatus 100 may further comprise a communication component 905. The communication component 905 can optionally include a wired communication component and/or a wireless communication component (e.g., WI-FI communication component, bluetooth communication component, etc.), typically used to establish a communication connection between the EIT imaging apparatus 100 and other computer devices.
Fig. 4 shows only EIT imaging apparatus 100 having partial components and implementing a contact impedance acquiring method of the EIT imaging apparatus, and it will be understood by those skilled in the art that the structure shown in fig. 4 does not constitute a limitation of the EIT imaging apparatus 100, and may include fewer or more components than illustrated, or may combine some components, or a different arrangement of components.
In the above embodiment, the different identified electrode pairs are used as the excitation electrode pairs to excite the excitation electrode pairs by using the preset excitation current, the excitation voltage of the non-excitation electrode pairs is sensed to obtain the current excitation voltage of the excitation electrode pairs, the minimum current excitation voltage is confirmed as the reference voltage, and the reference contact impedance is further determined, so that the contact impedance of each excitation electrode in the remaining excitation electrode pairs is determined according to the reference contact impedance and the residual current excitation voltage, the contact impedance of each excitation electrode in the excitation electrode pairs is calculated respectively, and the calculation accuracy of the electrode contact impedance is improved.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the spirit or scope of the application. Thus, if and when such modifications and variations of the present application fall within the scope of the claims and their equivalents, the present application is intended to cover such modifications and variations.
It should be understood that, although the steps in the flowcharts of the figures are shown in order as indicated by the arrows, these steps are not necessarily performed in order as indicated by the arrows. The steps are not strictly limited in order and may be performed in other orders, unless explicitly stated herein. Moreover, at least some of the steps in the flowcharts of the figures may include a plurality of sub-steps or stages that are not necessarily performed at the same time, but may be performed at different times, the order of their execution not necessarily being sequential, but may be performed in turn or alternately with other steps or at least a portion of the other steps or stages.
The foregoing list of preferred embodiments of the present application is, of course, not intended to limit the scope of the claims hereof, and therefore, equivalent changes as set forth in the claims hereof are intended to fall within the scope of the present application.
Claims (10)
1. A contact impedance acquisition method of an EIT imaging apparatus, the EIT imaging apparatus including a plurality of electrodes, the contact impedance acquisition method of the EIT imaging apparatus comprising:
sequentially identifying from the plurality of electrodes each excitation electrode pair, and all non-excitation electrode pairs under each excitation electrode pair, each excitation electrode pair comprising an odd excitation electrode and an even excitation electrode;
exciting each exciting electrode pair by using a preset exciting current, and sensing the exciting voltage of the corresponding non-exciting electrode pair to obtain the current exciting voltage of each exciting electrode pair;
taking the current excitation voltage with the minimum value in the current excitation voltage of each excitation electrode pair as the excitation voltage of the reference electrode pair;
according to the excitation voltage of the reference electrode pair and the preset excitation current, calculating the contact impedance of the odd excitation electrode and the even excitation electrode of the reference electrode pair to obtain an odd reference contact impedance and an even reference contact impedance; and
and respectively calculating the contact impedance of each excitation electrode in the residual excitation electrode pair according to the odd reference contact impedance, the even reference contact impedance and the residual current excitation voltage, wherein the odd reference contact impedance is used for calculating the contact impedance of the odd excitation electrode of the residual excitation electrode pair, and the even reference contact impedance is used for calculating the contact impedance of the even excitation electrode of the residual excitation electrode pair.
2. The method of claim 1, wherein the current excitation voltage is a sum of excitation voltages of all non-excitation electrode pairs corresponding to each excitation electrode pair.
3. The method of claim 2, wherein the sum of the current excitation voltages being the excitation voltages of the corresponding pairs of non-excitation electrodes is a result of sequentially identifying each excitation electrode pair and all pairs of non-excitation electrodes below each excitation electrode pair from the plurality of electrodes according to an adjacent injection method.
4. The contact impedance acquiring method of an EIT imaging apparatus according to claim 1, wherein the odd reference contact impedance and the even reference contact impedance are equal.
5. The method for acquiring contact impedance of EIT imaging apparatus according to claim 4, wherein the calculation formula of the odd reference contact impedance and the even reference contact impedance is: r is R odd_tar ＝R even_tar ＝U min /(2I), where R odd_tar Represents an odd reference contact resistance, R even_tar Represents even reference contact impedance, U min Representing the current excitation voltage with the smallest value, and I represents the preset excitation current.
6. The contact impedance obtaining method of EIT imaging apparatus according to claim 1, wherein calculating contact impedance of each excitation electrode in remaining pairs of excitation electrodes based on the odd reference contact impedance, the even reference contact impedance, and remaining current excitation voltage, respectively, comprises:
extracting the current excitation voltage of another excitation electrode pair containing the odd excitation electrode of the reference electrode pair to obtain the excitation voltage of the odd excitation electrode pair, and extracting the current excitation voltage of another excitation electrode pair containing the even excitation electrode of the reference electrode pair to obtain the excitation voltage of the even excitation electrode pair; and
and calculating to obtain the contact impedance of the odd excitation electrode of the other excitation electrode pair by using the excitation voltage of the odd excitation electrode pair, the preset excitation current and the odd reference contact impedance, and calculating to obtain the contact impedance of the even excitation electrode of the other excitation electrode pair by using the excitation voltage of the even excitation electrode pair, the preset excitation current and the even reference contact impedance.
7. The method for acquiring contact impedance of EIT imaging apparatus according to claim 6, wherein a calculation formula of the contact impedance of the odd excitation electrode is: r is R odd -R odd+2 ＝(U odd -U odd+1 ) 2, odd=2k+1, k=0, 1,2 … …, wherein odd represents an odd numberOrder of excitation electrodes, R odd And R is odd+2 Represents the contact impedance of the odd-numbered excitation electrodes, U odd Representing the corresponding current excitation voltage when the odd excitation electrode is the excitation electrode of the smaller order of the excitation electrode pairs.
8. The method for acquiring contact impedance of EIT imaging apparatus according to claim 6, wherein a calculation formula of the contact impedance of the even excitation electrode is: r is R even -R even+2 ＝(U even -U even+1 ) 2, even=2k, k=1, 2 … …, where even denotes the order of even excitation electrodes, R even And R is even+2 Represents the contact impedance of even excitation electrodes, U even Representing the corresponding current excitation voltage when an even number of excitation electrodes are used as the smaller-order excitation electrode in the excitation electrode pair.
9. A contact impedance acquiring apparatus of an EIT imaging device, the EIT imaging device including a plurality of electrodes, characterized in that the contact impedance acquiring apparatus of the EIT imaging device includes:
an injection module for sequentially identifying each excitation electrode pair, and all non-excitation electrode pairs under each excitation electrode pair, from the plurality of electrodes, each excitation electrode pair comprising an odd excitation electrode and an even excitation electrode;
the acquisition module is used for exciting each exciting electrode pair by using a preset exciting current and sensing the exciting voltage of the corresponding non-exciting electrode pair to obtain the current exciting voltage of each exciting electrode pair;
the confirmation module is used for taking the current excitation voltage with the minimum numerical value in the current excitation voltage of each excitation electrode pair as the excitation voltage of the reference electrode pair; and
the impedance calculation module is used for calculating the contact impedance of the odd excitation electrode and the even excitation electrode of the reference electrode pair according to the excitation voltage of the reference electrode pair and the preset excitation current to obtain an odd reference contact impedance and an even reference contact impedance, and respectively calculating the contact impedance of each excitation electrode of the remaining excitation electrode pair according to the odd reference contact impedance, the even reference contact impedance and the remaining current excitation voltage, wherein the odd reference contact impedance is used for calculating the contact impedance of the odd excitation electrode of the remaining excitation electrode pair, and the even reference contact impedance is used for calculating the contact impedance of the even excitation electrode of the remaining excitation electrode pair.
10. An EIT imaging apparatus comprising a number of electrodes, characterized in that the EIT imaging apparatus further comprises:
a memory for storing a computer program; and
a processor for executing the computer program to implement the contact impedance acquisition method of the EIT imaging apparatus according to any one of claims 1 to 8.
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