DE102020108804A1 - Apparatus and method for extracting a component associated with a specific physiological phenomenon based on the measurement of electrical properties, and reconstructing EIT data using the extracted component - Google Patents

Abstract

Disclosed is an apparatus and a method for extracting a component associated with a specific physiological phenomenon based on the measurement of electrical properties and reconstructing electrical impedance tomography (EIT) data using the extracted component. According to an embodiment of the invention, the device for extracting a specific component based on EIT and reconstructing the data may comprise: an electrode unit comprising a plurality of electrodes to be attached to a measurement area of the subject, an electrical properties measuring device, suitable for measuring a plurality of electrical properties of the subject over the plurality of attached electrodes over time, an EIT data generator suitable for generating EIT data based on a change in the plurality of measured electrical properties, a pattern extractor suitable for extracting specific pattern data the generated EIT data associated with a specific component caused by a specific physiological phenomenon of the subject, and an EIT data reconstructor suitable for reconstructing the generated EIT data as the EI corresponding to the specific component T data based on the extracted specific pattern data.

Description

background

The invention relates to a technical concept for extracting a component assigned to a specific physiological phenomenon based on the measurement of electrical properties and the reconstruction of electrical impedance tomography (EIT) data using the extracted component, and in particular to a device and a A method of extracting a component of a specific physiological phenomenon from a composite signal which is influenced by a change in internal electrical properties of a human body corresponding to a plurality of EIT-based physiological phenomena and reconstructing EIT data using the extracted component.

Description of the prior art

When the voltage is measured after a current is injected or the current is measured after a voltage is injected into a human body or similar volume conductor, the measured data may vary depending on the internal electrical properties such as conductivity and dielectric constant distribution, the size and shape of the volume conductor as well as the position, size and shape of the electrode.

In addition, there is Principal Component Analysis (PCA) or Independent Component Analysis (ICA) technology for extracting changed components that each correspond to specific causes.

Here, the PCA is used as a method of reducing dimensions, where an original signal is represented as a linear combination of major components with high energy.

Furthermore, the ICA relates to a calculation method for dividing a multivariate signal into statistically independent sub-components, the components containing statistically independent components as non-Gaussian signals, and the ICA can be used in the blind signal division, which is only statistical independence from each Signal needed.

However, the prior art does not take into account at all that the size and shape of the volume conductor and the position, shape and size of the electrode are not changed as a function of time, whereas the internal electrical properties of the volume conductor are changed as a function of time.

Accordingly, there is a need to propose a technology that extracts a component associated with a specific physiological phenomenon, taking into account a change in electrical properties in a state where the position and shape of an electrode with respect to a specific subject is invariable.

Further, the subject to be subjected to the EIT includes persons of all ages, such as an infant, child, adult, elderly, etc., men and women, and various races, with the size and shape of an area representing a Imaging should generally vary widely depending on age and obesity.

Therefore, a measurement method based on the excess weight needs to be selected, and the technology for extracting a component associated with a specific physiological phenomenon from a signal influenced by many physiological phenomena needs to be considered.

Here, the EIT technology generates an image by attaching a plurality of electrodes to a surface of a target subject to be measured, detecting the impedance of the target subject through the plurality of electrodes, and converting the detected impedance into the conductivity and dielectric constant of the target subject.

EIT technology is used to create an image of a specific internal area of a human body and is widely used in the medical field.

summary

According to the invention, only one component of a specific physiological phenomenon is to be extracted from a composite signal which is influenced by a change in the internal electrical properties of a human body in accordance with a large number of physiological phenomena.

According to the invention, components are to be extracted which are each caused by a change in the air within an upper airway, a change in the blood flow in a carotid, a movement of the neck while breathing, a movement of the tongue, a change in the air in the lungs or a change in the blood flow caused in the thorax.

According to the invention, an image is to be reconstructed that is based on a component that is assigned to a specific physiological phenomenon.

According to the invention, a method for feeding in current or voltage is to be changed, taking into account the size and shape of an area to be subjected to imaging, and thus a measurement area for the voltage or the current to be set flexibly.

According to the invention, an electrode pair for feeding in current or voltage is to be identified based on the extent of an area to be subjected to imaging, and a measurement area for the voltage or the current is thus to be determined in a flexible manner.

According to the invention, the quality of a reconstructed image is to be improved, the number of voltages which can be distinguished from the noise being increased, the measuring range for the voltage or the current being flexibly defined.

According to an embodiment of the invention, an apparatus for extracting a specific component based on electrical impedance tomography (EIT) and for reconstructing data comprises: an electrode unit having a plurality of electrodes to be attached to an area of a subject to be measured; an electrical properties meter capable of measuring a plurality of electrical properties of the subject over time by the plurality of attached electrodes; an EIT data generator adapted to generate EIT data based on a change in the plurality of measured electrical properties; a pattern extractor capable of extracting specific pattern data (data patterns) associated with a specific component caused by a certain physiological phenomenon of the subject from the generated EIT data; and an EIT data reconstructor capable of reconstructing the generated EIT data as the EIT data corresponding to a specific component based on the extracted specific pattern data.

The pattern extractor can use an element, selected from energy and frequency, of the generated EIT data by an element selected from a signal-to-noise ratio in the generated EIT data, a principal component analysis (PCA) and an independent component analysis (ICA), analyze and extract specific pattern data associated with a specific component caused by a certain physiological phenomenon of the subject with respect to a frequency component based on the analyzed energy or frequency.

The EIT data reconstructor can reconstruct the generated EIT data as the EIT data corresponding to the specific component based on a difference in relative voltage change between the extracted specific pattern data and the generated EIT data.

According to one embodiment of the invention, the device for extracting a specific component based on EIT and reconstructing the data can further contain an image restorer which is designed to restore an image based on the reconstructed EIT data which is assigned to a specific component.

The variety of electrical properties measured can include conductivity and dielectric constant distribution.

The specific component may include at least one of a change in air in a lung or an airway of the subject, a change in blood flow within a body, a change in a component within the body, and a change in movement of an area of the body.

According to an embodiment of the invention, an apparatus for measuring electrical properties based on EIT comprises: an electrode unit including a plurality of electrodes to be attached to a measurement area of the subject; and an electrical property meter configured to measure a plurality of electrical properties of the subject through the plurality of attached electrodes, the electrical property meter identifying an adjacent first and second electrode among the plurality of electrodes as a supply electrode pair, if a circumference of the measurement range is smaller than or equal to a measurement reference value, the first electrode and a third electrode, which is positioned further away from the first electrode than the second electrode, are identified as the supply electrode pair, if the extent of the measurement range is greater than the measurement reference value, and identifies a plurality of pairs of supply electrodes, the spacing of which is different according to a change in the circumference of the measurement area.

The electrical property measuring device can supply the identified supply electrode pair with current or voltage and measure the current or voltage induced by the current or voltage supplied by the plurality of attached electrodes.

The electrical property measuring device can change a voltage gain or a current gain according to the scope of the measuring range when the current or the voltage is induced by the injected current or voltage.

According to one embodiment of the invention, a method for extracting a specific component and reconstructing the EIT-based data comprises: by an electrical properties meter, measuring a plurality of electrical properties of a subject over time by the plurality of attached electrodes attached to a Measurement area of the subject are appropriate; by an EIT generator, generating EIT data based on a change in the plurality of measured electrical properties; by a pattern extractor, extracting specific pattern data associated with a specific component caused by a certain physiological phenomenon of the subject from the generated EIT data; and by an EIT data reconstructor, reconstructing the generated EIT data as EIT data corresponding to the specific component based on the extracted specific pattern data.

The extraction of specific pattern data associated with a specific component, which is caused by a certain physiological phenomenon of the subject, from the generated EIT data comprises: analyzing an element, selected from energy and frequency, of the generated EIT data by a Element selected from a signal-to-noise ratio in the generated EIT data, a principal component analysis (PCA) and an independent component analysis (ICA); and extracting specific pattern data associated with a specific component caused by a certain physiological phenomenon of the subject with respect to a frequency component based on the analyzed energy or frequency.

The reconstruction of the generated EIT data as EIT data corresponding to a specific component based on the extracted specific pattern data can reconstruct the generated EIT data as EIT data corresponding to the specific component based on a difference in relative Levels of voltage change between the extracted specific pattern data and the generated EIT data.

According to an embodiment of the invention, a method of measuring electrical properties based on EIT, in which the plurality of electrical properties of a subject are measured by a plurality of electrodes to be attached to a measurement area of the subject, may include: by an electrical property Measuring device, identifying an adjacent first and second electrode from a plurality of electrodes as a supply electrode pair when a circumference of the measurement area is less than or equal to a measurement reference value; by an electrical property meter, identifying the first electrode and a third electrode positioned farther from the first electrode than from the second electrode than the supply electrode pair when the perimeter of the measurement area is greater than the measurement reference value; and by an electrical property measuring device, identifying a plurality of pairs of supply electrodes the spacing of which is different according to a change in the circumference of the measurement area.

According to an embodiment of the invention, the method of measuring electrical properties based on EIT may further include: by the electrical properties measuring device, supplying current or voltage to the identified supply electrode pair; Measuring the current or voltage induced by the current or voltage supplied by the plurality of attached electrodes; and by the electrical property meter, changing a voltage gain or a current gain according to the scope of the measurement range when the current or voltage is induced from the supplied current or voltage.

Figure list

• 1 illustrates elements of an apparatus for extracting a specific component based on electrical impedance tomography (EIT) and reconstructing data according to an embodiment of the invention;
• 2 Figure 3 illustrates an embodiment relating to the generation of EIT data in accordance with an embodiment of the invention;
• 3A until 3G illustrate a method for extracting a specific component based on pattern data according to an embodiment of the invention;
• 4A illustrates elements of a sample data processor according to an embodiment of the invention;
• 4B Fig. 10 illustrates an embodiment relating to the pattern data according to an embodiment of the invention;
• 5 illustrates an embodiment in which an image is extracted by a device for extracting a specific Component and reconstruct data is restored, according to an embodiment of the invention;
• 6A and 6B illustrate embodiments relating to the measurement of electrical properties in accordance with an embodiment of the invention;
• 7th until 12th illustrate embodiments of an alternating combination of electrodes forming a pair for supplying current according to the measured girth of the subject;
• 13th Figure 3 is a flow diagram relating to a method for extracting a specific component and reconstructing data in accordance with an embodiment of the invention; and
• 14th Figure 3 is a flow diagram relating to a method of measuring electrical properties in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Various embodiments of the invention are described below with reference to the accompanying drawings.

Embodiments and terms used herein are not to be construed as limiting the invention to any particular form, and it is to be understood that various changes, equivalents, and / or alternatives can be made in these embodiments.

In the following descriptions, details of well-known functions or features are omitted if they are found to obscure the essence of the present inventive concept.

Further, terms used in the following descriptions are defined taking the functions of the elements into account, but they may be varied depending on the user, the intention or operation of an operator, and so on. Therefore, the definition must be based on the content described below.

With regard to the description of the drawings, the same reference symbols denote the same elements.

Unless otherwise noted in the context, it is intended that the singular forms include the plural forms as well.

In the description, the term “A or B”, “at least one of A and / or B”, or the like, may contain all possible combinations of the elements listed together.

The terms "first," "second," etc. may be used herein to describe items regardless of their order or importance, and are only used to distinguish one item from another without limiting the items.

It goes without saying that when a particular (e.g. first) element is referred to as “connected” or “coupled” to another (e.g. second) element (for function or communication), it is directly or through an additional (e.g. third) element can be connected or coupled to each other.

In this description, "trained to ~ (or set to ~)" can be used interchangeably with "suitable for ~", "having the ability to ~", "modified to ~", "manufactured to ~", "capable of ~" , or "designed to ~" be used by hardware or software as the case may be.

Under certain circumstances, a “device configured to ~” can mean that the device can be “capable of ~” together with another device or parts.

For example, a “processor designed (or set) to execute A, B and C” may refer to an exclusive processor (e.g., an embedded processor) to perform the operations, or to a general purpose processor (e.g., a central processing unit) Unit = CPU) or an application processor) capable of performing the operations by executing one or more software programs stored in a storage device.

Furthermore, “or” refers to “inclusive or” rather than “exclusive or”.

In other words, unless otherwise stated or the context does not indicate otherwise, “x uses a or b” means one of the natural inclusive permutations.

The terms "... area", "... unit" etc. used here refer to a unit for processing at least one function or operation, and this can be achieved by hardware, software, or a combination of hardware and software.

1 illustrates elements of an apparatus for extracting a specific Component based on electrical impedance tomography (EIT) and reconstructing the data according to an embodiment of the invention.

With reference to 1 contains a device 100 an electrode unit for extracting a specific component based on EIT and reconstructing data 110 , an electrical properties measuring device 120 , an EIT data generator 130 , a pattern extractor 140 and an EIT data reconstructor 150.

According to one embodiment of the invention, the electrode unit 110 contain a plurality of electrodes to be attached to a measurement area of a subject.

For example, the plurality of electrodes may include at least one of a single electrode or a combined electrode, and may include an EIT electrode for supplying current and measuring impedance data for voltage measurement.

For example, the EIT electrode is arranged on one side of a base plate made of a flexible elastic material and attached to the measurement area of the subject. According to one embodiment of the invention, the EIT electrode can be shaped like a belt or a vest.

Further, the EIT electrode is used for feeding a current with a relatively small current that a subject cannot perceive, for example, a high frequency current with a current less than or equal to 1 mA, and for measuring the induced voltage. Current-voltage data measured by the EIT electrode can be used to detect an internal pattern of a human body by an imaging algorithm.

According to one embodiment of the invention, the electrical properties measuring device measures 120 a plurality of electrical properties of a subject over time across the plurality of electrodes attached to the subject.

For example, the electrical properties measuring device 120 recognize a pair of supply electrodes among the plurality of electrodes based on the circumference of the measurement area, and supply the pair of supply electrodes with current or voltage. Here, the pair of supply electrodes can relate to a pair of electrodes for the supply of current or voltage.

Furthermore, the electrical properties measuring device 120 measure the current or voltage induced by the current or voltage by a pair of measuring electrodes from the other electrodes, with the exception of the pair of supply electrodes from the plurality of electrodes. Here, the pair of measuring electrodes can relate to a pair of electrodes for measuring the current or the voltage.

For example, the plurality of electrical properties can include the conductivity and the distribution of the dielectric constant of the induced current or voltage.

According to one embodiment of the invention, the electrical properties measuring device 120 identify a first and second adjacent electrode as a supply electrode pair from the plurality of electrodes if the circumference of the measurement area is less than or equal to a measurement reference value.

For example, the electrical properties measuring device 120 identify the first electrode and a third electrode as the pair of supply electrodes from the plurality of electrodes when the circumference of the measurement area is larger than the measurement reference value. In this case, the third electrode can refer to an electrode which, when viewed relatively, is positioned further away from the first electrode than from the second electrode.

According to one embodiment of the invention, the measurement reference value can be based on at least one element selected from the scope of the measurement range, the maximum or minimum measured value of the induced current or voltage and the noise level.

For example, the measurement reference value can be set or changed by a user at will.

In addition, the measurement reference value can be used as an index for identifying a distance between the electrodes making up the pair for power supply.

For example, when a distance between two electrodes forming the supply electrode pair increases, the maximum measured value and the minimum measured value may increase.

Furthermore, when a distance between two electrodes forming the supply electrode pair decreases, the maximum measured value and the minimum measured value may decrease.

According to one embodiment of the invention, the electrical properties measuring device 120 measure a variety of electrical properties within a voltage measurement range that was calculated excluding the minimum measured value from the maximum measured value.

In other words, according to the present invention, the method of feeding current or voltage is changed taking into account the size and shape of an area to be subjected to imaging, and therefore the measurement area of voltage or current is flexibly set.

According to one embodiment of the invention, the electrical properties measuring device 120 supply voltage or current to the supply electrode pair, and measure the current or voltage induced by the current or voltage by the measuring electrode pair identified among the other electrodes, with the exception of the supply electrode pair attached to the measurement area of the subject .

For example, the electrical properties measuring device 120 Measure approximately 208 electrical properties by changing the combination between the pair of supply electrodes for feeding the current or voltage and the pair of measuring electrodes for measuring the voltage or current within 16 electrodes.

More specifically, the electrical property measuring device 120 generate 208 number of time series data by measuring 208 electrical properties over a period of time.

For example, the pair of supply electrodes can relate to a pair of electrodes for the current or voltage supply.

Furthermore, the pair of measuring electrodes can refer to a pair of electrodes for measuring the current or the voltage that are induced by the supplied current or the voltage.

For example, the device 100 for extracting a specific component based on EIT and reconstructing the data, includes apparatus (not shown) for measuring electrical properties based on EIT that the electrode unit comprises 110 and the electrical properties measuring device 120 contains.

According to one embodiment of the invention, the EIT data generator 130 Generate EIT data based on a change in a variety of electrical properties. The generated EIT data can also be referred to as measured EIT data.

For example, the EIT data generator 130 Generate EIT data according to the voltage measurement range.

In other words, the EIT data generator 130 can generate EIT data between the maximum measured value and the minimum measured value of the voltage.

For example, the EIT data may include a change, noise, motion artifact, etc., of the variety of electrical properties. In other words, the EIT data may be affected by a change in impedance associated with upper airway stenosis, breathing exercise, blood flow in a carotid, and irregular movement of a lower jaw and tongue.

According to one embodiment of the invention, the pattern extractor 140 use the signal-to-noise ratio of the generated EIT data to identify at least a portion of the sample data from the generated EIT data.

For example, the EIT data may contain a variety of signal-to-noise ratios that vary based on a variety of electrical properties.

In other words, the pattern extractor 140 can identify sample data corresponding to a change in 16 electrical properties with a good signal-to-noise ratio among the changes in 208 electrical properties of the EIT data.

For example, the pattern data can also be referred to as frequency pattern data, which is assigned to a change in the scale of the electrical properties.

Further, the pattern data may correspond to at least a part of the frequency change data according to the change in the plurality of electrical properties within the EIT data.

According to one embodiment of the invention, the pattern extractor 140 extract the pattern data corresponding to a specific component caused by the physiological phenomenon of the subject from at least a part of the pattern data.

For example, the specific component may be a change in the internal air of a lung or a subject's airway, a change in blood flow within a body, a change in a component within a body, as well as a change in the movement of a part in the body.

For example, the pattern extractor 140 Use the signal-to-noise ratio in the EIT data, a skin component analysis (PCA), or an independent component analysis (ICA) to analyze the energy or frequency in the EIT data.

Furthermore, the pattern extractor 140 extract certain pattern data associated with a specific component caused by a certain physiological phenomenon of a subject with respect to a frequency component based on the analyzed energy or frequency.

According to the invention, it is possible to extract only a component caused by a certain physiological phenomenon from a composite signal which is influenced by a change in internal electrical properties of a human body according to a plurality of physiological phenomena.

In other words, according to the invention, it is possible to extract components from the measured EIT data, each by changing the air in an upper respiratory tract, changing the blood flow within a carotid, moving a neck while breathing, moving a tongue, changing air in the lungs, or change in chest blood flow.

According to an embodiment of the invention, the EIT data reconstructor 150 can reconstruct the EIT data as EIT data corresponding to a specific component based on the extracted pattern data.

For example, the EIT data reconstructor 150 may reconstruct the EIT data as EIT data corresponding to a specific component based on the difference in relative voltage change between the extracted specific pattern data and the EIT data.

In other words, the EIT data reconstructor 150 can use a least squares error method to rescale the EIT data because there is the same difference between the relative sizes of the sample data measured for certain time periods.

According to an alternative embodiment of the invention, a device 100 an image restorer for extracting a specific component based on EIT and reconstructing the data 160 contain.

According to one embodiment of the invention, the image restorer can 160 restore an image associated with a specific component based on the reconstructed EIT data.

For example, the image restorer 160 use the EIT data based on a specific component to reconstruct an image associated with the specific component.

For example, the image restorer can 160 if the specific component is a component caused by a change in air in the lungs or a change in chest blood flow, individually reconstruct an image of the change in air in the lungs or an image of the change in chest blood flow.

An embodiment of individually restoring the image of the change in air in the lungs or the image of the change in thoracic blood flow will be described later with reference to FIG 5 described.

According to the invention, it is possible to restore an image based on a component associated with a specific physiological phenomenon.

In other words, according to the invention, it is possible to improve the quality of a reconstructed image by increasing the number of voltages distinguishable from noise when the measurement range for the voltage or the current is set flexibly.

2 Figure 3 shows an embodiment relating to the generation of the EIT data according to an embodiment of the invention.

Shows in detail 2 an embodiment in which EIT data is generated relating to a subject's neck.

In operating condition 200 One method of extracting a specific component and reconstructing the data includes attaching a plurality of electrodes to a portion under a face of a subject.

In operating condition 210 the method of extracting a specific component and reconstructing the data includes measuring a variety of electrical properties that involve component changes, such as a breath-related motion artifact 211 , a flow of blood 212 , an obstruction of the upper airway 213 etc., due to the multitude of electrodes attached to one Section below the subject's face.

In operating condition 220 For example, the method of extracting a specific component and reconstructing the data may include measuring the plurality of electrical properties of the subject over time.

The large number of electrical properties to be measured can cause noise 221 , as well as noise caused by the subject's movement.

In operating condition 230 The process of extracting a specific component and reconstructing the data can be the generation of EIT data 231 based on a change in the variety of electrical properties. Here the EIT data can also be referred to as measured EIT data.

For example, the EIT data could 231 have been affected by a change in impedance associated with an upper airway stenosis, breathing exercise, blood flow in a carotid, and irregular movement of a lower jaw or tongue.

3A until 3G show a method for extracting a specific component based on pattern data according to an embodiment of the invention.

3A FIG. 13 shows a result where the EIT data generator according to an embodiment of the invention uses 16 electrodes to generate EIT data, which includes a change in the 208 electrical properties through the 208 channels. Here, the change in the electrical properties over time can show a change in the scale of the electrical properties. Furthermore, channels can be set based on a combination of 16 electrodes.

3B FIG. 14 shows a result where the pattern extractor according to an embodiment of the invention uses the signal-to-noise ratio to determine the changes of 16 electrical characteristics having a high signal-to-noise ratio (SNR) among the changes of FIG. 208 identify electrical properties.

For example, the pattern extractor may select 16 voltage channels that have the highest SNR among the 208 time-series voltage channels as inputs to an ICA algorithm.

3C FIG. 13 shows a result where the pattern extractor according to an embodiment of the invention identifies the pattern data corresponding to a change in 16 electrical properties. For example, the identified pattern data can correspond to an ICA component.

3D FIG. 10 shows a result that the pattern extractor according to an embodiment of the invention removes noise pattern data 300 , as well as noise pattern data 301 removed from 16 ICA components.

For example, if an independent source signal S is calculated, breathing exercise and blood flow components can be identified by spectral analysis.

When the Fast Fourier Transform is applied to all of the independent components of the independent source signal, the breathing component with fundamental rates corresponding to a breathing rate and a heart rate can be identified as breathing exercise and blood flow components. A modified source signal U can be calculated based on the following equation 1. $$U={\widehat{\mathrm{W.}}}^{-1}\widehat{\mathrm{S.}}$$

In equation 1, Ŵ ^-1 can denote a modified mixing matrix and Ŝ denote an independent source signal.

Ŵ ^-1 can be obtained by replacing those columns corresponding to elements of breathing exercise and blood flow with columns of 0.

3E Fig. 10 shows a result where the pattern extractor according to an embodiment of the invention extracts pattern data that of a specific component 310 correspond. For example, the particular component can 310 correspond to an upper airway signal.

3F Fig. 10 shows a result where the pattern extractor according to an embodiment of the invention applies filtering to the pattern data that of the specific component 310 correspond. Referring to 3F , corresponds to a graph 320 the specific component 310 , and a graph 321 corresponds to the upper airway signal passed through a low pass filter.

Here, 208 pieces of tension data corresponding to the upper airway stenosis can be restored to have the correct amplitude. Further, the low pass filter can be used to reduce the residual noise of the reconstructed voltage data without distorting a pattern of the upper airway stenosis.

3G Figure 12 shows a result where the EIT data reconstructor according to an embodiment of the invention reconstructs the EIT data including a change in 208 electrical properties corresponding to a specific component based on the extracted pattern data.

For example, the EIT data reconstructor can reconstruct the EIT data including a change in 208 electrical properties based on Equation 2 below. $${\text{V}}_{\text{j}}={\text{a}}_{\text{j}}{\text{U}}_{\text{UA}}+{\text{b}}_{\text{j}}$$

In Equation 2, V _j can be the j th channel voltage, U a modified source signal, and a _j and b _j constants corresponding to difference values between the parts of the voltage data.

In addition, the EIT data reconstructor can generate matrix data based on Equation 3 below, and the generated matrix data can correspond to Equation 4. $$\text{C.}={\left({\text{U}}_{\text{UA}}{}^{\text{T}}{\text{U}}_{\text{UA}}\right)}^{\text{-1}}{\text{U}}_{\text{UA}}{}^{\text{T}}\text{X}$$

In Equation 3, C can be the reconstructed EIT data, U the modified data, T the time, and X the originally generated EIT data. $$\mathrm{C.}={\left[\begin{array}{ccc}{a}_1& \cdots & a_{20\mathrm{8th}}\\ b_1& \cdots & {\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="DE102020108804A1\_0011.png,DE102020108804A1\_0016.png"\; state="\{\{state\}\}">b</figure-callout>}}_{20\mathrm{8th}}\end{array}\right]}^T$$

In Equation 4, C may be the reconstructed EIT data, a and b may be the constants corresponding to the voltage differences, and T may be time.

4A illustrates elements of a specimen data processor according to an embodiment of the invention.

4A shows operations of a specimen data processor 400 with a pattern extractor.

Referring to 4A removed a BAR processor 410 a boundary artifact when the specimen data processor 400 a mixed signal 401 receives.

A PCA processor also extracts 411 of the sample data processor 400 PCA sample data 402 corresponding to a major component of the voltage of the signal from which the boundary artifact is being removed.

Meanwhile, the sample data processor extracts 400 the PCA sample data 402 and outputs them as data assigned to the respiratory component.

An L-curve detector also extracts 412 of the sample data processor 400 L curve data from the PCA sample data 402 .

An ICA processor also records 413 of the sample data processor 400 ICA component data that corresponds to an ICA component.

An ICA selector can also be used 414 of the sample data processor 400 ICA sample data 403 select and output that correspond to a specific component among the ICA components.

Furthermore, a source comparator 415 of the sample data processor 400 a homogeneity between the PCA sample data 402 and the ICA template data 403 identify.

Ultimately, the sample data processor can 400 the PCA sample data 402 and the ICA pattern data 403 to reconstruct the respective EIT data.

4B Fig. 10 shows an embodiment related to pattern data according to an embodiment of the invention.

Referring to 4B are the frequency patterns of the mixed signal 401 who have favourited PCA pattern data 402 , as well as the ICA sample data 403 shown.

For example, contains the mixed signal 401 the PCA sample data 402 and the ICA pattern data 403 .

5 Figure 3 shows an embodiment wherein an image is restored by a device for extracting a specific component and reconstructing the data according to an embodiment of the invention.

Referring to 5 the device for extracting a specific component and reconstructing the data generates EIT data 500 corresponding to a composite signal extracts pattern data corresponding to a respiratory component 510 and extracts pattern data indicative of blood flow 511 correspond.

The device for extracting a specific component and reconstructing the data can be the respiratory component 510 use to image data 520 restore.

Furthermore, the apparatus for extracting a specific component and reconstructing the data can use image data 521 based on blood flow 511 reconstruct.

In other words, the device for extracting a specific component and reconstructing the data can separate the components corresponding to a change in the air in the lungs or a change in the thoracic blood flow from the EIT measurement data, and use the separated EIT data to Restore images individually based on the change in air in the lungs or the change in chest blood flow.

6A and 6B illustrate embodiments related to the measurement of electrical properties according to an embodiment of the invention.

Referring to 6A can be an electrode unit 600 containing a plurality of electrodes can be attached to a perimeter of a subject.

For example, the plurality of electrodes can contain a first electrode ε ₁ to a sixteenth electrode ε ₁₆ .

For example, the apparatus for extracting a specific component and reconstructing the data feeds current to a pair of supply electrodes 610 and measures the voltage via a pair of measuring electrodes 620 .

The pair of supply electrodes 610 may contain a second electrode ε ₂ and a third electrode ε ₃ , which are adjacent to one another.

The pair of measuring electrodes 620 may contain an eighth electrode ε ₈ and a ninth electrode ε ₉ , which are adjacent to one another.

Referring to 6B can the electrode unit 600 containing the plurality of electrodes can be attached to the perimeter of the subject.

For example, the device for extracting a specific component and reconstructing the data feeds current to a pair of supply electrodes 611 and measures the voltage through the pair of measuring electrodes 620 .

The pair of supply electrodes 611 may contain a second electrode ε ₂ and a fourth electrode ε ₄ , which are not adjacent to one another.

Here the supply electrode pair 611 contain the fourth electrode ε ₄ , which the third electrode ε ₃ skips.

The pair of measuring electrodes 620 can also contain the eighth electrode ε ₈ and the ninth electrode ε ₉ , which are adjacent to one another.

Meanwhile, the maximum and minimum values of the induced voltage can be varied depending on the method for feeding the current.

With a "0-jump" method for feeding the current between two adjacent electrodes, the internal current distribution between the feeding electrodes is focused and therefore the internal voltage can drop rapidly with increasing distance from the current feeding electrode.

In the case of a “1-jump” method, in which the next adjacent electrode is selected rather than the immediately adjacent electrode, the distance between two electrodes for feeding in the current can increase.

Then the internal current spreads spatially and slows down so much that the voltage decreases.

If all conditions of a patient are the same, “1-jump” is increased in the maximum value and minimum value compared to “0-jump”. In this case, the increase in the maximum value is larger than the increase in the minimum value, and therefore the difference between the maximum value and the minimum value, i.e., the voltage range, may relatively increase.

In this way, as the voltage range increases, a preset number of voltages distinguishable from noise increases, thereby improving the quality of the image.

If the distance between two electrodes for supplying current continues to increase, such as “2-step”, “3-step” or the like, this can be more effective for increasing the voltage range.

This is because the internal current spreads more as the distance between two electrodes for feeding the current increases.

Meanwhile, when the conductivity of a specific portion is changed, high sensitivity to that change is advantageous in order to create a high resolution image based on this change. In other words, “0 jump” can be the most advantageous in terms of spatial resolution.

7th Fig. 10 illustrates an embodiment of changing a power feed pair according to a measured girth of a subject.

Shows in detail 7th that, depending on the change in the girth of the subject, the number of channels and the voltage are varied, as well as changing the combination of a supply electrode pair.

The data 700 show that electrodes combined to form the supply electrode pair are adjacent to each other when a subject is 81 cm in circumference.

The data 701 show that one electrode is excluded between electrodes combined to form the supply electrode pair when a subject is 81 cm in circumference.

The data 702 show that electrodes combined to form the supply electrode pair are adjacent to each other when a subject is 170 cm in circumference.

The data 703 show that one electrode is excluded between electrodes combined to form the supply electrode pair when a subject is 170 cm in circumference.

In other words, if an electrode is excluded between electrodes that have been combined to form the supply electrode pair, the number of channels and the voltage measurement range may increase.

Further, as the girth of a subject increases, the number of channels can increase and the voltage measurement range can decrease.

8th Fig. 16 shows an embodiment in which the combination of electrodes constituting the pair of current feeds is changed depending on a measured girth of a subject.

Referring to 8th can the data 800 correspond to a voltage measurement range obtained by excluding the minimum value from the maximum value when combining adjacent electrodes to form the supply electrode pair.

The data 801 may correspond to the maximum value when adjacent electrodes are combined to form the supply electrode pair.

The data 802 may be the minimum value when adjacent electrodes are combined to form the supply electrode pair.

The data 810 may correspond to the voltage measurement range obtained by excluding the minimum value from the maximum value when excluding an electrode between electrodes that are combined to form the supply electrode pair.

The data 811 may be the maximum value when one electrode is excluded between electrodes that are combined to form the supply electrode pair.

The data 812 may be the minimum value when one electrode is excluded between electrodes that are combined to form the supply electrode pair.

9A Fig. 13 shows an embodiment wherein a combination of electrodes constituting the current feed pair is varied depending on a measured girth of a subject.

Shows in detail 9A the number of channels and the measured voltage based on a subject's breathing and a change in the combination of the supply electrode pair.

Referring to 9A can the data 900 correspond to inhalation when adjacent electrodes are combined to form the supply electrode pair.

The data 901 may correspond to exhalation when adjacent electrodes are combined to form the supply electrode pair.

The data 910 may correspond to inhalation when one electrode is excluded between electrodes that combine to form the supply electrode pair.

The data 911 may correspond to exhalation when one electrode is excluded between electrodes that combine to form the supply electrode pair.

9B Fig. 16 shows an embodiment wherein the combination of electrodes forming the current feed pair is varied depending on a measured girth of a subject.

Shows in detail 9B the number of channels and the measured voltage based on the change in the measured girth of the subject as well as changing the combination of the supply electrode pair.

The data 920 show that electrodes combined to form the supply electrode pair are adjacent to each other when a subject is 81 cm in circumference.

The data 921 show that electrodes combined to form the supply electrode pair are adjacent to each other when a subject is 106 cm in circumference.

The data 922 show that electrodes combined to form the supply electrode pair are adjacent to each other when a subject is 170 cm in circumference.

The data 930 show that one electrode is excluded between electrodes combined to form the supply electrode pair when a subject is 81 cm in circumference.

The data 931 show that one electrode is excluded between electrodes combined to form the supply electrode pair when a subject is 106 cm in circumference.

The data 932 show that one electrode is excluded between electrodes combined to form the supply electrode pair when a subject is 170 cm in circumference.

10 Fig. 10 illustrates an embodiment wherein the combination of electrodes forming the current feed pair is varied depending on a measured girth of a subject.

Referring to 10 can the data 1000 correspond to the voltage measurement range obtained by excluding the minimum value from the maximum value when adjacent electrodes are combined to form the supply electrode pair.

The data 1001 may correspond to the maximum value when adjacent electrodes are combined to form the supply electrode pair.

The data 1002 may be the minimum value when adjacent electrodes are combined to form the supply electrode pair.

For example, it can also be called a “0 jump” when adjacent electrodes are combined to form the supply electrode pair.

The The data 1010 may correspond to the voltage measurement range obtained by excluding the minimum value from the maximum value when excluding an electrode between electrodes that are combined to form the supply electrode pair.

The data 1011 may be the maximum value when one electrode is excluded between electrodes that are combined to form the supply electrode pair.

The data 1012 may be the minimum value when one electrode is excluded between electrodes that are combined to form the supply electrode pair.

For example, it can also be called “1-jump” when an electrode is excluded between electrodes that are combined to form the supply electrode pair.

According to one embodiment of the invention, the apparatus for measuring electrical properties measures a perimeter of an area of the patient to which the electrodes are attached.

Next, the apparatus for measuring electrical characteristics can estimate the maximum value, the minimum value and the range (i.e., maximum value to minimum value) from the graph or the table based on the measured amount. Here the device uses "0 jump" to measure electrical properties.

The device for measuring electrical properties can identify a gain so that the product of the maximum value of the voltage and the gain can be equal to the maximum input voltage of the ADC used in the system.

Alternatively, the apparatus for measuring electrical properties may calculate the voltage range corresponding to the measured range (i.e., maximum value to minimum value) from the graph or table when the gain is used.

The apparatus for measuring electrical properties can calculate the number of distinguishable voltages by dividing the above voltage range by the level of noise of the EIT system used.

The device for measuring electrical properties uses a "1 jump" if the number of voltages that can be distinguished has to be increased. However, the device for measuring electrical properties can use "2-jump" if the number of voltages that can be distinguished is insufficient, although "1-jump" is used.

Meanwhile, the apparatus for measuring electrical properties can repeat the above process to identify the minimal "jump" by which the number of distinguishable voltages is secured.

11 Fig. 16 shows an embodiment wherein the combination of electrodes constituting the current feed pair is varied depending on a measured girth of a subject.

Shows in detail 11 a voltage gain for setting the maximum value of the voltage to the maximum input voltage of the ADC by means of "0-jump" and "1-jump".

The data 1100 may correspond to a case where adjacent electrodes are combined to form the supply electrode pair.

The data 1101 may correspond to a case where an electrode is excluded between electrodes that are combined to form the supply electrode pair.

12th Fig. 16 shows an embodiment wherein a combination of electrodes forming the current feed pair is varied depending on a measured girth of a subject.

Shows in detail 12th that the number of distinguishable voltages is varied if the scope in "0-jump" and "1-jump" increases.

The data 1200 may correspond to a case where adjacent electrodes are combined to form the supply electrode pair.

The data 1201 may correspond to a case where an electrode is excluded between electrodes that are combined to form the supply electrode pair.

13th FIG. 10 shows a flow chart relating to a method for extracting a specific component and reconstructing the data according to an embodiment of the invention.

With reference to 13th contains in the operating state 1301 the method of extracting a specific component and reconstructing the data is measuring electrical properties of a subject.

In other words, the method of extracting a specific component and reconstructing the data may include measuring a plurality of electrical properties of a subject in accordance with the passage of time through the plurality of electrodes attached to a subject.

In operating condition 1302 the method of extracting a specific component and reconstructing the data may include generating EIT data.

In other words, the method of extracting a specific component and reconstructing the data may include generating the EIT data based on a change in the plurality of electrical properties measured.

In operating condition 1303 For example, the method of extracting a specific component and reconstructing the data can extract the specific pattern data from the EIT data.

In other words, the method of extracting a specific component and reconstructing the data can use one of the signal-to-noise ratio in the generated EIT data, PCA or ICA to analyze either the energy or the frequency of the generated EIT data.

Further, the method of extracting a specific component and reconstructing the data can extract specific pattern data associated with a specific component caused by a specific physiological phenomenon of a subject with respect to a frequency component based on the analyzed energy or frequency.

Operational 1304 For example, the method of extracting a specific component and reconstructing the data can reconstruct the EIT data based on the specific sample data.

In other words, the method of extracting a specific component and reconstructing the data can use the extracted specific pattern data to restore the previously generated EIT data as EIT data corresponding to a specific component.

In detail, the method of extracting a specific component and reconstructing the data may reveal a difference in the relative level of voltage change between the specific pattern data and the previously generated EIT Use data to restore the previously generated EIT data as EIT data corresponding to a specific component.

14th FIG. 13 is a flow diagram relating to a method for measuring electrical properties based on EIT according to an embodiment of the invention.

Referring to 14th contains in the operating state 1401 the method of measuring electrical properties based on EIT comparing an extent of a measurement range of a subject and a measurement reference value.

In operating condition 1402 The method for measuring electrical properties based on EIT may include identifying the first electrode and the second electrode as the supply electrode pair when the extent of the measurement area is less than or equal to the measurement reference value. Here, the first electrode and the second electrode can be adjacent to one another.

On the other hand, the method of measuring electrical properties based on EIT starts with the operating state 1403 if the scope of the measuring range is greater than the measurement reference value.

Operational 1403 the method of measuring electrical properties based on EIT compares the extent of the measurement range of the subject and the measurement reference value.

Operational 1404 the method for measuring electrical properties based on EIT can identify the first electrode and the third electrode as the supply electrode pair when the extent of the measurement area is larger than the measurement reference value.

Here the third electrode adjoins the second electrode, but is a little further away from the first electrode.

For example, the method of measuring electrical properties based on EIT may further include identifying a plurality of supply electrode pairs that differ in distance according to a change in the scope of the measurement area by repeating the operating states 1402 until 1404 are executed.

According to the invention, it is possible to extract only a component of a specific physiological phenomenon from a composite signal which is influenced by a change in internal electrical properties of a human body according to a plurality of physiological phenomena.

According to the invention, it is possible to extract components from electrical impedance tomography (EIT), which are each represented by a change in the air in an upper airway, a change in blood flow in a carotid, a movement of a neck while breathing, a movement of a tongue, cause a change in the air in a lungs or a change in chest blood flow.

According to the invention, it is possible to restore an image based on a component associated with a specific physiological phenomenon.

According to the invention, it is possible to change a method of supplying current or voltage by taking into account the size and shape of an area to be subjected to imaging, and thus flexibly setting an area for measuring the voltage or current.

According to the invention, it is possible to identify a pair of electrodes for feeding current or voltage based on the extent of an area to be subjected to imaging, thereby flexibly setting a measurement area for voltage or current.

According to the invention, it is possible to improve the quality of a reconstructed image by increasing the number of voltages distinguishable from noise when the measurement range for the voltage or the current is set flexibly.

The method according to one embodiment can be implemented in the form of a program instruction which is implemented by various computer means and recorded in a computer-readable medium. The computer readable medium may contain a program instruction, a data file, a data structure, etc. independently or in combination thereof.

The program instruction recorded on the medium may be specifically designed or fashioned for embodiments, or publicly known and usable by a person of ordinary skill in the computer software field. The computer readable recording medium may include, for example, magnetic media such as a hard disk, a floppy disk, and a magnetic tape; optical media such as CD-ROM and a DVD; magneto-optical media such as a flexible floppy disk; and a ROM, RAM, flash memory, or similar hardware device that is particularly is designed to store and implement a program instruction.

The program instruction can contain, for example, not only a machine language code that was created by a compiler, but also a high-level language code that can be executed by a computer via an interpreter or the like.

The hardware device can be designed to work as one or more software modules to carry out an operation according to an embodiment, and vice versa.

Although some embodiments have been described with exemplary examples and drawings, various changes and modifications can be made from the foregoing descriptions by those skilled in the art. For example, correct results will be achieved even though the techniques described are carried out in a different order from that of the method described and / or the elements described, such as a system, structure, device, circuit, etc. are in a different form coupled or combined than those of the method described, or may be replaced or exchanged for other elements or equivalents.

Therefore, equivalents to other designs, other embodiments, and claims also fall within the scope of the appended claims.

List of reference symbols

100

contraption

110

Electrode unit

120

Electrical properties measuring device

130

EIT data generator

140

Pattern extractor

150

EIT data reconstructor

160

Image restorer

200

Operating condition

210

Operating condition

211

Motion artifact

212

Blood flow

213

Closure of the upper airway

220

Operating condition

221

rush

230

Operating condition

231

EIT data

300

Noise pattern data

301

Noise pattern data

310

Specific component

320

graph

321

graph

400

Sample data processor

401

mixed signal

402

PCA sample data

403

ICA sample data

410

BAR processor

411

PCA processor

412

L curve detector

413

ICA processor

414

ICA selector

415

Source comparator

500

EIT data

510

Respiratory component

511

Blood flow

520

Image data

521

Image data

600

Electrode unit

610

Supply electrode pair

611

Supply electrode pair

620

Measuring electrode pair

700

Data (adjacent electrodes, circumference = 81cm)

701

Data (excluded electrode, circumference = 81cm)

702

Data (adjacent electrodes, circumference = 170cm)

703

Data (excluded electrode, circumference = 170cm)

800

Voltage measuring range data (adjacent electrodes)

801

Maximum value data (adjacent electrodes)

802

Minimum value data (adjacent electrodes)

810

Voltage measuring range data (excluded electrode)

811

Maximum value data (excluded electrode)

812

Minimum value data (excluded electrode)

900

Inhalation data (adjacent electrodes)

901

Exhalation data (adjacent electrodes)

910

Inhalation data (excluded electrode)

911

Exhalation data (excluded electrode)

920

Data (adjacent electrodes, circumference = 81cm)

921

Data (adjacent electrodes, circumference = 106cm)

922

Data (adjacent electrodes, circumference = 170cm)

930

Data (excluded electrode, circumference = 81cm)

931

Data (excluded electrode, circumference = 106cm)

932

Data (excluded electrode, circumference = 170cm)

1000

Voltage measuring range data (adjacent electrodes)

1001

Maximum value data (adjacent electrodes)

1002

Minimum value data (adjacent electrodes)

1010

Voltage measuring range data (excluded electrode)

1011

Maximum value data (excluded electrode)

1012

Minimum value data (excluded electrode)

1100

Data (adjacent electrodes)

1101

Data (excluded electrode)

1200

Data (adjacent electrodes)

1201

Data (excluded electrode)

1301

Operating condition (measuring electrical properties)

1302

Operating status (generation of EIT data)

1303

Operating status (extracting specific sample data from EIT data)

1304

Operating status (reconstruction of the EIT data based on the specific sample data)

1401

Operating status (scope of the measuring range less than / equal to the measurement reference value)

1402

Operating status (identify first and second electrodes as first pair of electrodes)

1403

Operating condition (scope of the measuring range greater than the measuring reference value)

1404

Operating status (identify first and third electrode as first pair of electrodes)

Claims (14)

Apparatus for extracting a specific component based on electrical impedance tomography (EIT) and reconstructing data, the apparatus comprising: an electrode unit having a plurality of electrodes to be attached to a measurement area of a subject; an electrical properties meter capable of measuring a plurality of electrical properties of the subject over time by the plurality of attached electrodes; an EIT data generator capable of generating EIT data based on a change in the plurality of measured electrical properties; a pattern extractor suitable for extracting specific pattern data associated with a specific component caused by a certain physiological phenomenon of the subject from the generated EIT data; and an EIT data reconstructor capable of reconstructing the generated EIT data as EIT data corresponding to the specific component based on the extracted specific pattern data. Device according to Claim 1 in which the pattern extractor analyzes an element selected from energy and frequency of the generated EIT data by an element selected from a signal-to-noise ratio in the generated EIT data, principal component analysis (PCA) and independent component analysis (ICA) , and extract specific pattern data associated with a specific component caused by a certain physiological phenomenon of the subject with respect to a frequency component based on the analyzed energy or frequency. Device according to Claim 1 or 2 wherein the EIT data reconstructor reconstructs the generated EIT data as EIT data corresponding to a specific component based on a difference in the relative voltage change level between the extracted specific pattern data and the generated EIT data. Device according to one of the Claims 1 until 3 which further comprises an image restorer capable of restoring an image associated with the specific component based on the reconstructed EIT data. Device according to one of the Claims 1 until 4th , in which the plurality of measured electrical properties includes conductivity and the distribution of dielectric constants. Device according to one of the Claims 1 until 5 wherein the specific component comprises at least one element selected from a change in air within a lungs or airway of the subject, a change in blood flow within a body, a change in a component in a body, and a change in movement of an area in the body . Apparatus for measuring electrical properties based on electrical impedance tomography (EIT), the apparatus comprising: an electrode unit having a plurality of electrodes to be attached to a measurement area of a subject; and an electrical properties meter capable of measuring a plurality of electrical properties of the subject through the plurality of attached electrodes; wherein the electrical property measuring device identifies an adjacent first and second electrode among the plurality of electrodes as a supply electrode pair when a circumference of the measurement area is less than or equal to a measurement reference value, the first electrode and a third electrode positioned farther from the first electrode is identified as the second electrode, as the supply electrode pair when the circumference of the measurement area is larger than the measurement reference value, and a plurality of supply electrode pairs which differ in distance according to a change in the circumference of the measurement area. Device according to Claim 7 wherein the electrical property meter supplies current or voltage to the identified supply electrode pair and measures the current or voltage induced by the current or voltage supplied by the plurality of attached electrodes. Device according to Claim 7 or 8th in which the electrical property measuring device changes a current gain or a voltage gain according to the scope of the measurement range when the current or voltage is induced by the supplied current or voltage. A method of extracting a specific component and reconstructing data based on electrical impedance tomography ([EIT), the method comprising: by an electrical property measuring device, measuring a plurality of electrical properties of a subject over time by a plurality of attached electrodes attached to a measurement area of the subject; by an EIT data generator, generating EIT data based on a change in the plurality of measured electrical properties; by a pattern extractor, extracting specific pattern data associated with a specific component caused by a certain physiological phenomenon of the subject from the generated EIT data; and by an EIT data reconstructor, reconstructing the generated EIT data as EIT data corresponding to a specific component based on the extracted specific pattern data. Procedure according to Claim 10 , in which the extraction of specific pattern data associated with a specific component caused by a certain physiological phenomenon of the subject from the generated EIT data comprises: analyzing an element selected from energy and frequency of the generated EIT data by an element , selected from a signal-to-noise ratio of the generated EIT data, a principal component analysis (PCA) and an independent component analysis (ICA); and extracting specific pattern data associated with a specific component caused by a certain physiological phenomenon of the subject with respect to a frequency component based on the analyzed energy or frequency. Procedure according to Claim 10 or 11 , in which the reconstruction of the generated EIT data as EIT data corresponding to the specific component based on the extracted specific pattern data comprises: reconstructing the generated EIT data as EIT data corresponding to the specific component based on a Difference in the relative voltage change level between the extracted specific pattern data and the generated EIT data. Method for measuring electrical properties based on electrical impedance tomography (EIT), in which a multiplicity of electrical properties of a subject are measured via a multiplicity of electrodes which are to be attached to a measurement area of the subject, the method comprising: by an electrical property measuring device, identifying an adjacent first and second electrode from the plurality of electrodes as a supply electrode pair when a circumference of the measurement area is less than or equal to a measurement reference value; by an electrical property meter, identifying the first electrode and a third electrode positioned farther from the first electrode than the second electrode when the perimeter of the measurement area is greater than the measurement reference value; and by an electrical characteristic meter, identifying a plurality of pairs of supply electrodes which are different in distance according to a change in the circumference of the measurement area. Procedure according to Claim 13 further comprising: by the electrical property meter, supplying current or voltage to the identified supply electrode pair; Measuring the current or voltage induced by the current or voltage supplied by the plurality of attached electrodes; and by the electrical property meter, changing a voltage gain or a current gain according to the scope of the measurement range when the current or voltage is induced from the supplied current or voltage.

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