CN112617794A

CN112617794A - Measuring device for electrical impedance imaging and measuring method thereof

Info

Publication number: CN112617794A
Application number: CN202011636785.3A
Authority: CN
Inventors: 陆彧
Original assignee: Suzhou Helci Medical Instrument Co ltd; Dianqi Biomedical Technology Beijing Co ltd
Current assignee: Suzhou Helci Medical Instrument Co ltd; Dianqi Biomedical Technology Beijing Co ltd
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2021-04-09
Anticipated expiration: 2040-12-31
Also published as: CN112617794B; CN114947803A; CN115054223A

Abstract

The present disclosure describes a measurement device for electrical impedance imaging, comprising: the system comprises an acquisition module and a processing module, wherein the acquisition module is used for applying an excitation signal to an object to be imaged and measuring a response signal at the same time, the processing module is connected with the acquisition module and is used for processing the response signal, the processing module comprises a first processing unit and a second processing unit, the first processing unit is connected with a measuring unit and receives the response signal, the second processing unit is connected with the first processing unit and receives the response signal, the first processing unit receives and processes the response signal to obtain a target response signal, and the second processing unit receives and processes the target response signal to obtain target information. In this case, the accuracy of the measuring apparatus can be effectively improved, and the power consumption of the measuring apparatus can be effectively reduced.

Description

Measuring device for electrical impedance imaging and measuring method thereof

Technical Field

The present disclosure relates to a measurement apparatus for electrical impedance imaging and a measurement method thereof.

Background

The electrical impedance imaging technology is that through an electrode group arranged on the surface of an object to be imaged, current with certain frequency and amplitude is applied to the object to be measured, response voltage is measured at the same time, and finally an image capable of reflecting the internal electrical impedance distribution information of the object to be imaged is obtained by using a corresponding imaging algorithm.

The traditional electrical impedance imaging technology generally applies a sinusoidal current excitation signal to an imaging target, then uses a high-speed analog-to-digital converter to perform high-speed sampling on a response sinusoidal voltage signal, and then performs digital quadrature demodulation on the sampling signal to acquire electrical impedance information of the imaging target. In the conventional electrical impedance imaging technology, high-power-consumption chips such as field programmable gate arrays and high-speed ADCs and a processor with high power consumption are generally required to meet the requirements of the digital quadrature demodulation method.

Disclosure of Invention

The present disclosure has been made in view of the above-described circumstances, and an object thereof is to provide a measuring apparatus for electrical impedance imaging having higher accuracy and lower power consumption, and a measuring method thereof.

To this end, a first aspect of the present disclosure provides a measurement device for electrical impedance imaging, characterized by comprising: the system comprises an acquisition module and a processing module, wherein the acquisition module is used for applying an excitation signal to an object to be imaged and measuring a response signal, the processing module is connected with the acquisition module and is used for processing the response signal, the acquisition module comprises a measuring unit and an excitation source used for providing the excitation signal for the measuring unit, the measuring unit is used for applying the excitation signal to the object to be imaged and measuring the response signal generated by the excitation signal, the processing module comprises a first processing unit and a second processing unit, the first processing unit is connected with the measuring unit and receives the response signal, the second processing unit is connected with the first processing unit, the first processing unit receives and processes the response signal to obtain a target response signal, the second processing unit receives and processes the target response signal to obtain target information, and the first processing unit comprises a first operational amplifier, A second operational amplifier, a differential amplifier, a programmable gain amplifier, and an analog-to-digital converter, wherein the first processing unit is configured to connect an input terminal of the first operational amplifier and an input terminal of the second operational amplifier with the measuring unit respectively, connect output terminals of the first operational amplifier and the second operational amplifier with an input terminal of the differential amplifier respectively, connect an output terminal of the differential amplifier to an input terminal of the programmable gain amplifier via a rc filter circuit, connect an output terminal of the programmable gain amplifier to the analog-to-digital converter via an anti-aliasing filter circuit, receive the target response signal and sample from the target response signal at a preset frequency in a target period to obtain a target sequence, and construct a homodromous component and a quadrature component corresponding to the target sequence based on the target response signal, thereby obtaining the target information based on the target sequence, and the homodromous component and the orthogonal component.

In the present disclosure, the acquisition module may apply an excitation signal to the object to be imaged and measure the response signal, and the processing module may include a first processing unit and a second processing unit, which may sequentially process the response signal to obtain the target information. In this case, the accuracy of the measuring apparatus can be effectively improved, and the power consumption of the measuring apparatus can be effectively reduced.

In the measurement apparatus according to the first aspect of the present disclosure, optionally, the excitation signal is a square wave current signal, and the response signal is a response voltage signal. In this case, the measuring device is capable of applying a square wave current signal to the object to be imaged and of acquiring a response voltage signal resulting from the square wave current signal.

In the measurement apparatus according to the first aspect of the present disclosure, optionally, the measurement unit includes an electrode array including a plurality of electrodes, a first selection subunit configured to select an excitation electrode from the electrode array, and a second selection subunit configured to select a measurement electrode from the electrode array, where the excitation electrode is an electrode for applying the excitation signal to the object to be imaged, and the measurement electrode is an electrode for obtaining the response signal from the object to be imaged. Thereby, the application of an excitation signal to the object to be imaged by the measuring device can be facilitated, and the obtaining of a response signal by the measuring device can be facilitated.

In the measurement apparatus according to the first aspect of the present disclosure, optionally, the second processing unit obtains a plurality of target sequences corresponding to a plurality of target periods, averages sampling results located at the same relative position in the plurality of target sequences respectively to obtain a plurality of target sampling results, and composes the plurality of target sampling results into one averaged target sequence. Therefore, the measuring device can have high precision.

In the measurement apparatus according to the first aspect of the present disclosure, optionally, the second processing unit constructs a direct component and an orthogonal component corresponding to the average target sequence based on the target response signal, so as to obtain the target information based on the target sequence and the direct component and the orthogonal component. In this case, the target information can be obtained based on the average target sequence, so that the accuracy of the measuring apparatus can be effectively improved.

In the measurement apparatus according to the first aspect of the present disclosure, optionally, the second processing unit obtains the amplitude of the homodromous component and the amplitude of the orthogonal component based on the average target sequence and the homodromous component and the orthogonal component, and obtains the target information based on the amplitude of the homodromous component and the amplitude of the orthogonal component. Thereby, the target information can be obtained based on the average target sequence.

In the measurement apparatus according to the first aspect of the present disclosure, optionally, the electrodes of the electrode array are in contact with an object to be imaged. In this case, it can be facilitated for the measurement unit to apply excitation signals to the object to be imaged and for the measurement unit to acquire response signals.

In the measuring apparatus according to the first aspect of the present disclosure, optionally, the target information is an amplitude of a fundamental frequency sinusoidal component in the target response signal. Thereby, it is possible to facilitate obtaining the target information.

A second aspect of the present disclosure provides a measurement method for electrical impedance imaging, characterized by comprising: the method comprises the steps of applying an excitation signal to an object to be imaged and measuring a response signal generated by the excitation signal, carrying out first processing on the response signal to obtain a target response signal, and carrying out second processing on the target response signal to obtain target information, wherein the first processing comprises first amplification processing, signal conversion processing, first filtering processing, second amplification processing, second filtering processing and analog-digital conversion processing, the second processing comprises sampling from the target response signal at a preset frequency in a target period to obtain a target sequence, and constructing an homodromous component and an orthogonal component corresponding to the target sequence based on the target response signal, so that the target information is obtained based on the target sequence and the homodromous component and the orthogonal component.

In the present disclosure, an excitation signal may be applied to an object to be imaged and a response signal may be measured at the same time, and the response signal may be sequentially subjected to a first processing and a second processing to acquire target information. In this case, the accuracy of the measurement method can be effectively improved, and the power consumption of the measurement method can be effectively reduced.

In the measurement method according to the second aspect of the present disclosure, optionally, a plurality of target periods are respectively sampled to obtain a plurality of target sequences, sampling results at the same relative position in the plurality of target sequences are respectively averaged to obtain a plurality of target sampling results, the plurality of target sampling results are combined into one average target sequence, and a homodromous component and an orthogonal component corresponding to the average target sequence are configured based on the target response signal, so that the target information is obtained based on the average target sequence and the homodromous component and the orthogonal component. In this case, the target information can be obtained based on the average target sequence, so that the accuracy of the measurement method can be effectively improved.

According to the present disclosure, a measuring apparatus for electrical impedance imaging and a measuring method thereof with higher accuracy and lower power consumption can be provided.

Drawings

Fig. 1 is a block diagram showing a structure of a measurement apparatus according to an example of the present disclosure.

Fig. 2 is a circuit schematic diagram illustrating a measurement unit and a first processing unit according to an example of the present disclosure.

Fig. 3 is a schematic diagram illustrating a measurement unit according to an example of the present disclosure.

Fig. 4 is a schematic diagram showing a structure of an electrode array according to an example of the present disclosure.

Fig. 5 is a schematic diagram showing an application of an electrode array according to an example of the present disclosure.

Fig. 6 is a circuit schematic diagram illustrating a first processing unit according to an example of the present disclosure.

Fig. 7 illustrates a circuit diagram of an isoelectric point generation module according to an example of the present disclosure.

Fig. 8 is a flow diagram illustrating a measurement method for electrical impedance imaging according to an example of the present disclosure.

Detailed Description

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same components are denoted by the same reference numerals, and redundant description thereof is omitted. The drawings are schematic and the ratio of the dimensions of the components and the shapes of the components may be different from the actual ones.

It is noted that the terms "comprises," "comprising," and "having," and any variations thereof, in this disclosure, for example, a process, method, system, article, or apparatus that comprises or has a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include or have other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The present disclosure provides a measurement device (which may sometimes be referred to simply as a measurement device) for electrical impedance imaging. The measurement apparatus 1 (see fig. 1) according to the embodiment of the present disclosure can be applied to an electrical impedance imaging technique. According to the present disclosure, it is possible to provide a measuring apparatus 1 for electrical impedance imaging which is simple in structure and has higher accuracy and lower power consumption. For example, the measurement device 1 according to the present disclosure may be a portable device. The measuring device 1 may be powered by a battery.

Fig. 1 is a block diagram showing a structure of a measurement apparatus 1 according to an example of the present disclosure. Fig. 2 is a circuit schematic diagram illustrating the measurement unit 110 and the first processing unit 210 according to an example of the present disclosure. .

In some examples, referring to fig. 1, the measurement device 1 may include an acquisition module 10 and a processing module 20. Wherein the processing module 20 can be connected with the acquisition module 10.

In some examples, the acquisition module 10 may be used to apply excitation signals to an object to be imaged. The acquisition module 10 may measure the response signal. Wherein the response signal may be due to the excitation signal.

In some examples, the object to be imaged may be an object having different resistance or resistivity distributions, such as a human body or the like.

In some examples, the excitation signal may be a current or voltage signal that is safe with respect to the object to be imaged. In some examples, the response signal may be a voltage or current signal generated after the excitation signal is applied to the object to be imaged. For example, the acquisition module 10 may apply a safe square wave current signal to the object to be imaged, and after the square wave current signal flows through the object to be imaged, the acquisition module 10 may acquire a response voltage signal corresponding to the square wave current signal. In this case, the measuring apparatus 1 is capable of applying a square wave current signal to the object to be imaged and of acquiring a response voltage signal resulting from the square wave current signal.

In some examples, the acquisition module 10 may include a measurement unit 110 and an excitation source 120 (see fig. 1-3). The excitation source 120 may be connected to the measurement unit 110, and may provide an excitation signal to the measurement unit 110.

Fig. 3 is a schematic diagram illustrating a measurement unit 110 according to an example of the present disclosure. Fig. 4 is a schematic diagram illustrating the structure of an electrode array 1110 according to an example of the present disclosure. Fig. 5 is a schematic diagram illustrating an application of an electrode array 1110 according to an example of the present disclosure.

In some examples, the measurement unit 110 may contact the object to be imaged. In some examples, the measurement unit 110 can include an electrode array 1110 (see FIGS. 3-5) comprising a plurality of electrodes. In some examples, each electrode in the electrode array 1110 may be in contact with an object to be imaged, respectively. In this case, it can be facilitated for the measurement unit to apply excitation signals to the object to be imaged and for the measurement unit to acquire response signals. In some examples, measurement unit 110 may configure electrodes in electrode array 1110 on the object to be imaged in such a way as to contact the surface of the object to be imaged. In some examples, the electrodes in the electrode array 1110 may be arranged in a straight pattern in sequence. In some examples, the electrodes in the electrode array 1110 may be evenly distributed. In some examples, the electrode array 1110 may be disposed in a surrounding manner on the object to be imaged. In this case, the subsequent acquisition of more comprehensive related information of the object to be imaged can be facilitated. For example, the electrode array 1110 may be disposed on a flexible band (e.g., a strap). In this case, the medical staff may arrange the flexible belt on the object to be imaged in such a manner as to surround the object to be imaged, and may bring the electrodes distributed on the flexible belt into contact with the surface of the object to be imaged. For example, the plurality of electrodes in the electrode array 1110 may be sequentially arranged along the length direction of the flexible strip and uniformly distributed on the flexible strip. The two ends of the flexible band may have means for mutual cooperation and for fixation. The flexible strap may be arranged on the object to be imaged in a manner surrounding the object to be imaged by means for fixing. A plurality of electrodes on the flexible belt may be in contact with a surface of an object to be imaged.

In some examples, the measurement unit 110 may apply an excitation signal to the object to be imaged. In some examples, measurement unit 110 may apply an excitation signal to the object to be imaged through electrodes of electrode array 1110 that are in contact with the object to be imaged.

In some examples, the measurement unit 110 may further include a first selection subunit 1120 (see fig. 3). Thereby, it can be facilitated for the measuring device 1 to apply an excitation signal to the object to be imaged. In some examples, first selection subunit 1120 may be configured to select a number of electrodes from electrode array 1110 as actuation electrodes. Wherein the excitation electrodes may be electrodes for applying an excitation signal to the object to be imaged. In some examples, the number of excitation electrodes may be two. In some examples, the actuation electrodes in electrode array 1110 may be variable. In some examples, as described above, electrode array 1110 may include a plurality of electrodes. For example, referring to fig. 4, the plurality of electrodes may be a start electrode D1, electrodes D2, …, a stop electrode D16, and the like, respectively. In some examples, when the electrodes in the electrode array 1110 are sequentially arranged in a straight pattern, the start electrode D1 and the end electrode D16 may be the first electrode and the last electrode in the electrode array 1110 (see fig. 4) along the length direction M, respectively. In some examples, the plurality of electrodes may include an electrode corresponding to any one of the electrodes. That is, the electrodes of the plurality of electrodes may be corresponding. Any one of the plurality of electrodes may be matched to its corresponding electrode in the plurality of electrodes. In some examples, the first selection subunit 1120 may sequentially select two corresponding electrodes as the excitation electrodes along the surrounding direction L or the length direction M of the electrode array 1110, starting from the starting electrode D1. In some examples, the corresponding two electrodes may be set at the discretion of the skilled person.

In some examples, the corresponding two electrodes may be adjacent two electrodes. The first selection subunit 1120 may select two adjacent electrodes as excitation electrodes. In some examples, the first selection subunit 1120 may sequentially select two adjacent electrodes as the excitation electrodes along the surrounding direction L of the electrode array, starting from the starting electrode D1. For example, the first selection subunit 1120 may first select the electrode D1 (i.e., the start electrode D1) and the electrode D2 as excitation electrodes, and then may sequentially select the electrode D2 and the electrode D3, the electrode D3 and the electrode D4, and the like as excitation electrodes (see fig. 4 and 5 (a)).

In other examples, where the electrode array 1110 is rounded, the corresponding two electrodes may be the two electrodes that are furthest apart (see fig. 4 and 5 (b)). For example, the first selection subunit 1120 may first select the electrode D1 and the electrode D9 as excitation electrodes, and then may sequentially select the electrode D2 and the electrode D10, the electrode D3 and the electrode D11, and the like as excitation electrodes.

In some examples, the first selection subunit 1120 may select several electrodes from the electrode array 1110 as excitation electrodes, which may apply an excitation signal from the excitation source 120 to the object to be imaged. For example, the excitation signal may be a square wave current signal from the excitation source 120, and the first selection subunit 1120 may select a number of electrodes from the electrode array 1110 to apply the square wave current to the object to be imaged.

In some examples, after the measurement unit 110 applies the excitation signal to the object to be imaged, the measurement unit 110 may measure the response signal. Specifically, the measurement unit 110 may apply an excitation signal to the object to be imaged through an electrode in contact with the object to be imaged, the excitation signal may generate a response signal through the object to be imaged, and the measurement unit 110 may measure the response signal through the electrode in contact with the object to be imaged.

In some examples, the measurement unit 110 may further include a second selection subunit 1130 (see fig. 3). Thereby, the measurement device 1 can be facilitated to obtain the response signal. In some examples, the second selection subunit 1130 may select several electrodes from the electrode array 1110 as measurement electrodes. Wherein the measuring electrode may be an electrode for measuring and acquiring a response signal from the object to be imaged. In some examples, the number of measurement electrodes may be two. In some examples, the second selection subunit 1130 may select two other adjacent electrodes other than the excitation electrode from the electrode array 1110 as the measurement electrodes. In some examples, the measurement electrodes in the electrode array 1110 may be variable. In some examples, the second selection subunit 1130 may sequentially select two adjacent electrodes other than the excitation electrode as the measurement electrodes in the surrounding direction L of the electrode array, starting from the starting electrode D1. For example, if electrode D1 and electrode D9 are excitation electrodes, the second selector subunit 1130 may select electrode D2 and electrode D3, electrode D3 and electrode D4, electrode D4 and electrode D5, and so on, in that order, as measurement electrodes. In some examples, start electrode D1 and stop electrode D16 (i.e., electrode D16) can be considered to be two adjacent electrodes.

In some examples, the second selection subunit 1130 may select several electrodes from the electrode array 1110 as measurement electrodes, and the measurement unit 110 may acquire a response signal through measurement of the measurement electrodes. For example, when a square wave current is applied to the object to be imaged, the second selection subunit 1130 may select two electrodes from the electrode array 1110 as measurement electrodes, and the measurement unit 110 may acquire, through the measurement electrodes, a voltage (i.e., a response voltage signal) between corresponding positions on the object to be imaged (i.e., positions where the two electrodes are respectively in contact with the object to be imaged), and the voltage may be output as a response signal.

In some examples, the first selection subunit 1120 may replace the excitation electrode after one cycle of the measurement electrode selection from the start electrode D1 to the end electrode D16. In this case, the first selection subunit 1120 may sequentially select two corresponding electrodes as the excitation electrodes along the surrounding direction L of the electrode array 1110. In other examples, the excitation signal may be an excitation current. The first selection subunit 1120 may replace the excitation electrodes when the excitation current crosses zero or has a constant phase delay from zero.

In some examples, the measurement unit 110 may begin acquisition of the response signal with the measurement electrode after a predetermined time from when the excitation electrode is replaced. In this case, the acquired signal can be more accurate, and the accuracy of the measuring apparatus 1 can be effectively improved. In some examples, the predetermined time may be set by the person of ordinary skill in the relevant art.

In some examples, the acquisition module 10 may also include an excitation source 120. In some examples, excitation source 120 may be coupled to measurement unit 110. In some examples, the excitation source 120 may provide an excitation signal to the measurement unit 110. In some examples, the excitation signal may be a current having a preset frequency and a preset amplitude. In some examples, the excitation signal may be a square wave current, a sine wave current, a triangular wave current, or the like. In some examples, the person of interest may adjust or set the excitation signal transmitted by the excitation source 120. For example, the associated person may adjust or set the frequency, amplitude, type, etc. of the excitation signal transmitted by the excitation source 120. In some examples, the excitation signal generated by the excitation source 120 may be a constant current excitation. In some examples, the frequency of the excitation signal generated by the excitation source 120 may be between 30KHz and 80 KHz. For example, the excitation source 120 may generate a square wave current having a frequency of 50 KHz.

In some examples, as described above, the measurement device 1 may further include a processing module 20 (see fig. 1). In some examples, processing module 20 may be coupled to acquisition module 10 and receive the response signals for processing.

In some examples, the processing module 20 may include a first processing unit 210 and a second processing unit 220 (see fig. 1). Wherein the second processing unit 220 may be connected with the first processing unit 210.

In some examples, the first processing unit 210 may be connected with the measurement unit 110 to receive the response signal. In some examples, the first processing unit 210 may receive the response signal and process to obtain a target response signal.

Fig. 6 is a circuit schematic diagram illustrating a first processing unit 210 according to an example of the present disclosure.

In some examples, the first processing unit 210 may include a first operational amplifier 2110 and a second operational amplifier 2120 (see fig. 6). In some examples, the first and second

operational amplifiers

2110, 2120 may each have an input and an output. In some examples, an input of the first operational amplifier 2110 and an input of the second operational amplifier 2120 may be respectively connected with the measurement unit 110. For example, the first operational amplifier 2110 may have a positive phase input terminal and a negative phase input terminal, and the first operational amplifier 2110 may be substantially formed as a follower structure. The non-inverting input of the first operational amplifier 2110 is connected to the measurement unit 110 for receiving the response signal. The negative input terminal of the first operational amplifier 2110 is connected to the output terminal of the first operational amplifier 2110. The second operational amplifier 2120 may have a positive phase input terminal and a negative phase input terminal, and the second operational amplifier 2120 may be formed substantially in a follower configuration. The non-inverting input of the second operational amplifier 2120 is connected to the measurement unit 110 to receive the response signal. The negative input terminal of the second operational amplifier 2120 is connected to the output terminal of the second operational amplifier 2120. In this case, the response signal acquired by the measuring electrode may flow through the first and second

operational amplifiers

2110 and 2120, respectively, and the first and second

operational amplifiers

2110 and 2120 may buffer-amplify the response signal, respectively. For example, the response signal acquired by the measurement unit 110 may be buffer-amplified by the first operational amplifier 2110 and the second operational amplifier 2120 to obtain a first response signal and a second response signal (equivalent to one amplification process described in a subsequent measurement method), that is, the response signal may flow through the first operational amplifier 2110 to obtain the first response signal, and the response signal may flow through the second operational amplifier 2120 to obtain the second response signal. Therefore, the method is beneficial to acquiring information with higher precision subsequently.

In some examples, the first and second

operational amplifiers

2110, 2120 may have high input impedance. For example, the input impedance of the first operational amplifier 2110 and the second operational amplifier 2120 may be hundreds of kilo-ohms or more, or mega-ohms or the like. This can effectively suppress the influence of contact resistance caused by contact between the electrode and the skin.

In some examples, the first processing unit 210 may further include a differential amplifier 2130 (see fig. 6). In some examples, the differential amplifier 2130 may have two inputs (a positive phase input and a negative phase input) and an output. In some examples, the output of the first operational amplifier 2110 and the output of the second operational amplifier 2120 may be connected to the inputs of a differential amplifier 2130, respectively. For example, the output terminal of the first operational amplifier 2110 is connected to the non-inverting input terminal of the differential amplifier 2130; the output terminal of the second operational amplifier 2120 is connected to the negative phase input terminal of the differential amplifier 2130. In this case, the first response signal and the second response signal may respectively flow in from the input of the differential amplifier 2130 and may flow out from the output of the differential amplifier 2130 to obtain the third response signal. In some examples, the third response signal may be a single-ended signal (equivalent to a signal conversion process described in a subsequent measurement method). Thereby, the differential amplifier 2130 can convert the first response signal and the second response signal into the third response signal.

In some examples, the differential amplifier 2130 may have a high common-mode rejection ratio. Therefore, common mode interference such as power frequency interference and electrode polarization voltage can be effectively inhibited.

In some examples, the first processing unit 210 may further include a programmable gain amplifier 2140 (see fig. 6). In some examples, the programmable gain amplifier 2140 may have an input and an output. In some examples, the output of the differential amplifier 2130 may be connected to the input of the programmable gain amplifier 2140 via a rc filter circuit. That is, a rc blocking filter circuit may be disposed between the output of the differential amplifier 2130 and the input of the programmable gain amplifier 2140. Examples of the invention are not limited in this regard and in some examples, the output of the differential amplifier 2130 may be directly connected to the input of the programmable gain amplifier 2140. That is, the third response signal may flow directly from the output of the differential amplifier 2130 into the input of the programmable gain amplifier 2140. In this case, the programmable gain amplifier 2140 is able to adjust the amplitude of the third response signal.

In some examples, the rc blocking filter circuit may include a first capacitor and a first resistor. In some examples, the first capacitor may have a first connection end and a second connection end. The first resistor may have a third connection terminal and a fourth connection terminal. In some examples, the first connection end of the first capacitance may be connected with an output of the differential amplifier 2130. The second connection of the first capacitor may be connected to the input of the programmable gain amplifier 2140. In some examples, the third connection terminal of the first resistor may be connected to the second connection terminal of the first capacitor. In some examples, the fourth connection terminal of the first resistor may be grounded.

In some examples, the third response signal may flow from the output of the differential amplifier 2130 through a rc filter circuit into the input of the programmable gain amplifier 2140 (equivalent to one filtering process described in the subsequent measurement method). In this case, the third response signal can flow through the rc blocking filter circuit, so that the dc component in the third response signal can be effectively filtered.

In some examples, the third response signal flowing through the rc blocking filter circuit may flow from the input of the programmable gain amplifier 2140. For example, the programmable gain amplifier 2140 may have a positive phase input and a negative phase input. The programmable gain amplifier 2140 may be formed substantially as a follower structure. The non-inverting input terminal of the programmable gain amplifier 2140 may be connected to the second connection terminal of the first capacitor. The negative input of programmable gain amplifier 2140 may be connected to the output of programmable gain amplifier 2140. In this case, a third response signal may flow in from the input terminal of the programmable gain amplifier 2140, and may flow out from the output terminal of the programmable gain amplifier 2140 to obtain a fourth response signal (equivalent to the secondary amplification process described in the subsequent measurement method). Thereby, the amplitude of the third response signal can be adjusted.

In some examples, the first processing unit 210 may also include an analog-to-digital converter 2150 (see fig. 6). In some examples, analog-to-digital converter 2150 may have an input. In some examples, the output of programmable gain amplifier 2140 may be connected to the input of analog-to-digital converter 2150 via an anti-aliasing filter circuit. That is, an anti-aliasing filter circuit may be provided between the output of programmable gain amplifier 2140 and the input of analog-to-digital converter 2150. Examples of the disclosure are not limited in this regard, and in some examples, the output of programmable gain amplifier 2140 may be directly connected to the input of analog-to-digital converter 2150. That is, the fourth response signal may flow from the output of programmable gain amplifier 2140 directly into the input of analog-to-digital converter 2150. In this case, the fourth response signal can be converted to a digital signal via the analog-to-digital converter 2150.

In some examples, the anti-aliasing filtering circuit may include a second capacitor and a second resistor. In some examples, the second resistor may have a fifth connection terminal and a sixth connection terminal. The second capacitor may have a seventh connection terminal and an eighth connection terminal. In some examples, the fifth connection terminal of the second resistor may be connected to the output terminal of the programmable gain amplifier 2140. The sixth connection of the second resistor may be connected to an input of the analog-to-digital converter 2150. In some examples, the seventh connection terminal of the second capacitor may be connected to the sixth connection terminal of the second resistor. In some examples, the eighth connection terminal of the second capacitor may be grounded.

In some examples, the fourth response signal may flow from the output of programmable gain amplifier 2140 into the input of analog-to-digital converter 2150 via an anti-aliasing filtering circuit (equivalent to the secondary filtering process described later). In this case, the fourth response signal can flow through the anti-aliasing filter circuit, whereby the influence of high-frequency harmonics and noise can be effectively suppressed.

In some examples, a fourth response signal flowing through the anti-aliasing filtering circuit may flow from an input of the analog-to-digital converter 2150, and the fourth response signal may obtain a target response signal via the analog-to-digital converter 2150 (equivalent to an analog-to-digital conversion process described later). In this case, the fourth response signal can be converted to a digital signal by the analog-to-digital converter 2150. Therefore, the target information can be conveniently acquired subsequently.

In some examples, as described above, the first processing unit 210 may be configured such that the inputs of the first operational amplifier 2110 and the second operational amplifier 2120 are respectively connected with the measurement unit 110, the outputs of the first operational amplifier 2110 and the second operational amplifier 2120 may be respectively connected with the inputs of the differential amplifier 2130, the output of the differential amplifier 2130 may be connected to the input of the programmable gain amplifier 2140 via a rc (resistive-capacitive) blocking filter circuit, and the output of the programmable gain amplifier 2140 may be connected to the input of the analog-to-digital converter 2150 via an anti-aliasing filter circuit. In this case, the accuracy of the target information acquired subsequently can be effectively improved by the first processing unit 210, the influence of noise can be effectively reduced, and the power consumption of the measuring apparatus 1 can be effectively reduced.

In some examples, as described above, the processing module 20 may further include the second processing unit 220 (see fig. 1). In some examples, the second processing unit 220 may be connected with the first processing unit 210. In some examples, the second processing unit 220 may be connected with the first processing unit 210 by transmission wires. For example, analog-to-digital converter 2150 may have an output. The second processing module 220 may be coupled to an output of the analog-to-digital converter 2150 to receive the target response signal. In other examples, the second processing unit 220 may be wirelessly connected with the first processing unit 210. In some examples, the second processing unit 220 may receive the target response signal from the first processing unit 210 and process to obtain the target information.

In some examples, the second processing unit 220 may receive the target response signal, as described above. In some examples, the second processing unit 220 may sample from the target response signal to obtain a plurality of sampling results to compose the target sequence. In some examples, the second processing unit 220 may sample the target response signal within the target period to obtain a plurality of sampling results to compose the target sequence. In some examples, the target period may correspond to one period of the excitation signal. In some examples, the second processing unit 220 may sample the target response signal at a preset frequency within the target period to acquire the target sequence. That is, the second processing unit 220 may sample the target response signal every target time within the target period. In this case, the second processing unit 220 may obtain a plurality of sampling results within the target period, and the second processing unit 220 may group the plurality of sampling results into one target sequence. For example, the sampling of the target response signal by the second processing unit 220 may be consecutive sampling with equal time interval of T/N (i.e. the target time is T/N), and the second sampling module 220 may obtain N sampling results in a target period and form a sequence V_s(k) In that respect Where T may be the period of the excitation signal, k 0,1, 2. In some examples, the second processing unit 220 may acquire from a start time of the target period. Examples of the present disclosure are not limited thereto, and in some examples, the second processing unit 220 may start acquisition from other times of the target period.

In some examples, the second processing unit 220 may obtain a plurality of sampling results in each target period and respectively constitute a plurality of target sequences. Wherein each target period may correspond to a target sequence. In some examples, the sampling results of any two target sequences may be in a one-to-one correspondence. In some examples, the corresponding two sampling results may be at respective positions of the respective target periods. That is, the time intervals of the two sampling results at the time of the respective target periods and the start time of the respective target periods may be equal. In some examples, the second processing unit 220 may average the sampling results at corresponding positions within the plurality of target sequences respectively to obtain a plurality of target sampling results. In this case, the second processing unit 220 may group a plurality of target sampling results into one average target sequence. This enables the measuring apparatus 1 to have high accuracy.

In some examples, the second processing unit 220 may construct the homodromous component and the quadrature component corresponding to the target sequence or the average target sequence based on the target response signal. In some examples, the target response signal may be a triangular wave signal, a square wave signal, or the like, and the second processing unit 220 may construct a homotropic component and a quadrature component of the fundamental frequency corresponding to the target sequence or the average target sequence based on the target response signal. For example, the target response signal may be a square wave signal. The square wave signal may be represented in the frequency domain as a weighted superposition of the sinusoidal signal with the same frequency and its odd harmonic signals, for example, the square wave signal may satisfy:

wherein A is_mMay be the amplitude of a square wave signal. In this case, if the target response signal is a square wave signal, the homodromous component of the fundamental frequency corresponding to the target sequence or the average target sequence may satisfy:

the orthogonal components of the fundamental frequency corresponding to the target sequence or the average target sequence may satisfy:

however, examples of the present disclosure are not limited thereto, and in some examples, the target response signal may be a sinusoidal signal, and the second processing unit 220 may construct a homotropic component and a quadrature component corresponding to the target sequence or the average target sequence based on the target response signal.

In some examples, the second processing unit 220 may obtain the target information based on the target sequence (or the average target sequence), and the co-directional component and the orthogonal component. In this case, the accuracy of the measuring apparatus 1 can be effectively improved.

In some examples, the second processing unit 220 may obtain the magnitudes of the in-directional component and the orthogonal component based on the target sequence (or the average target sequence), and the in-directional component and the orthogonal component. Therefore, the amplitude of the homodromous component and the amplitude of the orthogonal component can be obtained, and the target information can be conveniently obtained subsequently. In some examples, the second processing unit 220 may perform a dot product on the target sequence (or the average target sequence) with the in-direction component and the orthogonal component, respectively, and may obtain the amplitudes of the in-direction component and the orthogonal component, respectively. For example, if the target response signal is a square wave signal, the amplitude of the homodromous component may satisfy:

the magnitude of the quadrature component may satisfy:

wherein A is expressed as the amplitude of the fundamental frequency sinusoidal component in the target response signal and satisfies: a is 4A_mPhi, which is an additional phase shift due to the fact that the sampling by the second processing unit 220 does not start from the start time of each target period, i.e. the 0 time.

In some examples, the second processing unit 220 may obtain the target information based on the amplitude of the homodromous component and the amplitude of the orthogonal component. Thereby, the target information can be obtained. Wherein the target information may be used to reflect electrical impedance information of the object to be imaged. For example, the second processing unit 220 may further obtain the amplitude of the fundamental frequency sinusoidal component corresponding to the target response signal based on the amplitudes of the homodromous component and the orthogonal component, and satisfy:

where N is expressed as the number of samples in the target period. The amplitude of the fundamental frequency sinusoidal components may be targeted information. Thereby, it is possible to facilitate obtaining the target information.

In some examples, the measurement apparatus 1 may further include a display module (not shown) for displaying a resistivity distribution of the object to be imaged. In some examples, the display module may receive the target information. In some examples, the display module may convert the target information into electrical impedance information and display it. For example, if the amplitude of the fundamental frequency sinusoidal component is used as the target information, the measuring device 1 may adopt a constant current excitation mode, the display module may convert the amplitude of the fundamental frequency sinusoidal component into electrical impedance information by a constant current amplitude factor, and the display module may display the electrical impedance information.

Fig. 7 is a circuit diagram illustrating an isoelectric point generation module 30 according to an example of the present disclosure.

In some examples, the measurement device 1 may be powered by multiple power sources (e.g., dual power sources). In this case, the grounding in the individual modules of the measuring device 1 can be "grounded" in the usual sense. I.e. the ground in the individual modules of the measuring device 1 may be the actual ground. For example, the fourth connection of the first resistor may be actually grounded. The eighth connection of the second capacitor may be actually grounded.

In some examples, the current excitation device 1 may be powered by a single power supply. In this case, the grounding in the various modules of the measuring device 1 may be to a "virtual ground" (i.e., "isoelectric point"). In other words, the ground in each module of the current excitation device 1 may be a virtual ground. For example, the fourth connection terminal of the first resistor may be connected to an equipotential point. The eighth connection terminal of the second capacitor may be connected to an equipotential point.

In some examples, the voltage of the isoelectric point may be any voltage between the supply voltage and 0V. For example, the voltage of the isoelectric point may be half of the supply voltage.

In some examples, the isoelectric point may be provided by isoelectric point generation module 30. In some examples, as shown in fig. 7, the isoelectric point generation module 30 may include a third resistor 310, a fourth resistor 320, a third capacitor 330, and an operational amplifier 340. One end of the third resistor 310 may be connected to a power supply voltage. The other end of the third resistor 310 may be connected to a non-inverting input terminal of the operational amplifier 340. The supply voltage may be denoted VCC. One end of the fourth resistor 320 may be connected to the non-inverting input terminal of the operational amplifier 340. The other end of the fourth resistor 320 may be actually grounded. The third resistor 310 and the fourth resistor 320 may divide the power voltage VCC in fig. 7 to obtain an equipotential voltage.

In some examples, as shown in fig. 7, one end of the third capacitor 330 may be connected to the non-inverting input of the operational amplifier 340. The other terminal of the third capacitor 330 may be substantially grounded. In some examples, the third capacitance 330 may be a filter capacitance. In this case, noise in the equipotential voltage can be filtered out by the third capacitor 330.

In some examples, as shown in fig. 7, the negative input of operational amplifier 340 may be connected to the output of operational amplifier 340. In this case, the operational amplifier 340 can constitute an impedance transformation circuit, thereby increasing the driving capability of the equipotential voltage.

In some examples, the output of the operational amplifier 340 is an isoelectric point. For example, in the single power supply mode, the output terminal of the operational amplifier 340 may be used to connect the fourth connection terminal of the first resistor; the output of the operational amplifier 340 may be used to connect the eighth connection of the second capacitor.

In an embodiment to which the present disclosure relates, a measurement method for electrical impedance imaging is provided (see fig. 8). In the present embodiment, referring to fig. 8, the measurement method for electrical impedance imaging may include applying an excitation signal to an object to be imaged and simultaneously measuring a response signal (step S10); the measurement method for electrical impedance imaging may include performing a first processing on the response signal to obtain a target response signal (step S20); the target response signal is subjected to the second processing to obtain the target information (step S30). According to the measuring method disclosed by the invention, the precision of the measuring method can be effectively improved, and the power consumption of the measuring method can be effectively reduced. In some examples, the acquisition and processing of the object to be imaged, the excitation signal and the response signal in the measurement method may be as described above in relation to the object to be imaged, the excitation signal and the response signal.

In step S10, an excitation signal is applied to the object to be imaged and a response signal is measured simultaneously, as described above.

In some examples, step S10 may be implemented with acquisition module 10. For example, excitation signals may be applied to the object to be imaged by means of the acquisition module 10 in the measuring apparatus 1, and response signals may be measured simultaneously. Wherein the excitation signal may be a current or a voltage which is safe with respect to the object to be imaged. The response signal may be a voltage or a current generated after the excitation signal is applied to the object to be imaged.

In step S20, the response signal is subjected to the first processing to obtain the target response signal as described above.

In some examples, the acquisition and processing of the target response signal in the measurement method may be referred to the target response signal described above. See in particular the processing of the response signal by the first processing unit 210. In some examples, the first processing may include first amplification processing, signal conversion processing, first filtering processing, second amplification processing, second filtering processing, and analog-to-digital conversion processing. In some examples, step S20 may be implemented with the first processing unit 210. In some examples, the response signal may be processed a first time with the first processing unit 210 to obtain a target response signal.

In step S30, the target response signal is subjected to the second processing to obtain the target information as described above. In some examples, the acquisition and processing of the target information in the measurement method may be referred to the related description of the target information above. In some examples, the second processing may include sampling from the target response signal at a preset frequency in the target period to obtain the target sequence, and constructing the corresponding homodyne component and orthogonal component of the target sequence based on the target response signal, thereby obtaining the target information based on the target sequence and the homodyne component and orthogonal component. In some examples, step S30 may be implemented with the second processing unit 220. In some examples, the response signal may be processed a second time with the second processing unit 220 to obtain the target information.

In some examples, a plurality of target sequences may be obtained by sampling a plurality of target periods respectively in the measurement method. In some examples, the sampling results at the same relative position in the multiple target sequences may be respectively averaged to obtain multiple target sampling results. Multiple target sample results may be grouped into an average target sequence. The target information may be obtained by averaging the target sequences. In this case, the accuracy of the measurement method can be effectively improved. In some examples, the sampling results in the same relative position in the target sequences may be equal in time interval between the time of acquiring the sampling result in each target period and the start time of the target period. See in particular the above description of the correlation of the averaged target sequences.

While the present disclosure has been described in detail in connection with the drawings and examples, it should be understood that the above description is not intended to limit the disclosure in any way. Those skilled in the art can make modifications and variations to the present disclosure as needed without departing from the true spirit and scope of the disclosure, which fall within the scope of the disclosure.

Claims

1. A measurement device for electrical impedance imaging, comprising: the system comprises an acquisition module and a processing module, wherein the acquisition module is used for applying an excitation signal to an object to be imaged and measuring a response signal, the processing module is connected with the acquisition module and is used for processing the response signal, the acquisition module comprises a measuring unit and an excitation source used for providing the excitation signal for the measuring unit, the measuring unit is used for applying the excitation signal to the object to be imaged and measuring the response signal generated by the excitation signal, the processing module comprises a first processing unit and a second processing unit, the first processing unit is connected with the measuring unit and receives the response signal, the second processing unit is connected with the first processing unit, the first processing unit receives and processes the response signal to obtain a target response signal, the second processing unit receives and processes the target response signal to obtain target information, and the first processing unit comprises a first operational amplifier, A second operational amplifier, a differential amplifier, a programmable gain amplifier, and an analog-to-digital converter, wherein the first processing unit is configured to connect an input terminal of the first operational amplifier and an input terminal of the second operational amplifier with the measuring unit respectively, connect output terminals of the first operational amplifier and the second operational amplifier with an input terminal of the differential amplifier respectively, connect an output terminal of the differential amplifier to an input terminal of the programmable gain amplifier via a rc filter circuit, connect an output terminal of the programmable gain amplifier to the analog-to-digital converter via an anti-aliasing filter circuit, receive the target response signal and sample from the target response signal at a preset frequency in a target period to obtain a target sequence, and construct a homodromous component and a quadrature component corresponding to the target sequence based on the target response signal, thereby obtaining the target information based on the target sequence, and the homodromous component and the orthogonal component.

2. Measurement device for electrical impedance imaging according to claim 1,

the excitation signal is a square wave current signal, and the response signal is a response voltage signal.

3. Measurement device for electrical impedance imaging according to claim 1,

the measuring unit comprises an electrode array comprising a plurality of electrodes, a first selection subunit for selecting excitation electrodes from the electrode array, and a second selection subunit for selecting measuring electrodes from the electrode array, wherein the excitation electrodes are electrodes for applying the excitation signals to the object to be imaged, and the measuring electrodes are electrodes for measuring and acquiring the response signals from the object to be imaged.

4. Measurement device for electrical impedance imaging according to claim 1,

the second processing unit obtains a plurality of target sequences corresponding to a plurality of target periods, averages the sampling results at the same relative position in the plurality of target sequences respectively to obtain a plurality of target sampling results, and combines the plurality of target sampling results into an average target sequence.

5. A measurement device for electrical impedance imaging according to claim 4,

the second processing unit constructs the same-direction component and the orthogonal component corresponding to the average target sequence based on the target response signal, so as to obtain the target information based on the average target sequence and the same-direction component and the orthogonal component.

6. A measurement device for electrical impedance imaging according to claim 5,

the second processing unit obtains the amplitude of the same-direction component and the amplitude of the orthogonal component based on the average target sequence and the same-direction component and the orthogonal component, and obtains the target information based on the amplitude of the same-direction component and the amplitude of the orthogonal component.

7. A measurement device for electrical impedance imaging according to claim 3,

the electrodes in the electrode array are in contact with an object to be imaged.

8. Measurement device for electrical impedance imaging according to claim 2,

the target information is the amplitude of the fundamental frequency sinusoidal components in the target response signal.

9. A measurement method for electrical impedance imaging, comprising: the method comprises the steps of applying an excitation signal to an object to be imaged and measuring a response signal generated by the excitation signal, carrying out first processing on the response signal to obtain a target response signal, and carrying out second processing on the target response signal to obtain target information, wherein the first processing comprises first amplification processing, signal conversion processing, first filtering processing, second amplification processing, second filtering processing and analog-digital conversion processing, the second processing comprises sampling from the target response signal at a preset frequency in a target period to obtain a target sequence, and constructing an homodromous component and an orthogonal component corresponding to the target sequence based on the target response signal, so that the target information is obtained based on the target sequence and the homodromous component and the orthogonal component.

10. A measurement method for electrical impedance imaging according to claim 9,

sampling a plurality of target periods respectively to obtain a plurality of target sequences, averaging sampling results positioned at the same relative position in the plurality of target sequences respectively to obtain a plurality of target sampling results, forming the plurality of target sampling results into an average target sequence, and constructing a same-direction component and an orthogonal component corresponding to the average target sequence based on the target response signal, thereby obtaining the target information based on the average target sequence and the same-direction component and the orthogonal component.