Electrical impedance tomography response signal processing module

Abstract

The present disclosure describes a processing module for a response signal of electrical impedance imaging, wherein the response signal is generated by applying an excitation signal to an object to be imaged, and the processing module includes a first processing unit and a second processing unit connected to the first processing unit, wherein the first processing unit is configured to receive the response signal and process it to obtain a target response signal, and the second processing unit is configured to receive the target response signal and sample the target response signal at a preset frequency within a target period to obtain a target sequence, and construct an in-phase component and an orthogonal component corresponding to the target sequence based on the target response signal, thereby obtaining target information based on the target sequence, the in-phase component and the orthogonal component. Thus, the measurement accuracy of electrical impedance imaging can be improved.

Description

[0001] This application is a divisional application of a patent application with an application date of December 31, 2020, application number 2020116367853, and invention name "Measuring device and measuring method for electrical impedance imaging". Technical Field

[0002] The present disclosure specifically relates to a processing module for response signals of electrical impedance imaging. Background Art

[0003] Electrical impedance imaging technology is a technology that uses an electrode group arranged on the surface of the object to be imaged to apply a current of a certain frequency and amplitude to the object to be measured, and simultaneously measures the response voltage. Finally, a corresponding imaging algorithm is used to obtain an image that can reflect the internal electrical impedance distribution information of the object to be imaged.

[0004] Traditional electrical impedance imaging technology usually applies a sinusoidal current excitation signal to the imaging target, then uses a high-speed analog-to-digital converter to sample the response sinusoidal voltage signal at high speed, and then performs digital orthogonal demodulation on the sampled signal to obtain the electrical impedance information of the imaging target. In traditional electrical impedance imaging technology, it is usually necessary to use high-power chips such as field programmable logic gate arrays, high-speed ADCs, and processors with high power consumption to meet the needs of digital orthogonal demodulation methods. Summary of the invention

[0005] The present disclosure is proposed in view of the above situation, and its purpose is to provide a measuring device and a measuring method for electrical impedance imaging with higher accuracy and lower power consumption.

[0006] To this end, a first aspect of the present disclosure provides a measuring device for electrical impedance imaging, characterized in that it includes: an acquisition module for applying an excitation signal to an imaging object and measuring a response signal, and a processing module connected to the acquisition module and used to process the response signal, the acquisition module includes a measuring unit and an excitation source for providing the excitation signal to the measuring unit, the measuring unit is used to apply the excitation signal to the imaging object and measure the response signal generated by the excitation signal, the processing module includes a first processing unit connected to the measuring unit and receiving the response signal, and a second processing unit connected to the first processing unit, the first processing unit receives the response signal and processes it to obtain a target response signal, the second processing unit receives the target response signal and processes it to obtain target information, the first processing unit includes a first operational amplifier, a second operational amplifier, and a third operational amplifier. two operational amplifiers, a differential amplifier, a programmable gain amplifier, and an analog-to-digital converter, the first processing unit is configured such that the input end of the first operational amplifier and the input end of the second operational amplifier are respectively connected to the measuring unit, the output ends of the first operational amplifier and the second operational amplifier are respectively connected to the input end of the differential amplifier, the output end of the differential amplifier is connected to the input end of the programmable gain amplifier via a resistor-capacitor DC isolation filter circuit, the output end of the programmable gain amplifier is connected to the analog-to-digital converter via an anti-aliasing filter circuit, the second processing unit is configured to receive the target response signal and sample from the target response signal at a preset frequency within a target period to obtain a target sequence, and construct an in-phase component and an orthogonal component corresponding to the target sequence based on the target response signal, so as to obtain the target information based on the target sequence, and the in-phase component and the orthogonal component.

[0007] In the present disclosure, the acquisition module may apply an excitation signal to the imaging object and measure a response signal, and the processing module may include a first processing unit and a second processing unit, and the first processing unit and the second processing unit may process the response signal in sequence to obtain target information. In this case, the accuracy of the measuring device can be effectively improved, and the power consumption of the measuring device can be effectively reduced.

[0008] In the measuring device involved in 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 can apply a square wave current signal to the object to be imaged, and can collect a response voltage signal generated by the square wave current signal.

[0009] In the measuring device involved in the first aspect of the present disclosure, optionally, the measuring unit includes an electrode array including a plurality of electrodes, a first selection subunit for selecting an excitation electrode from the electrode array, and a second selection subunit for selecting a measurement electrode from the electrode array, wherein 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 measuring and obtaining the response signal from the object to be imaged. Thus, it is convenient for the measuring device to apply the excitation signal to the object to be imaged, and it is convenient for the measuring device to obtain the response signal.

[0010] In the measurement device involved in the first aspect of the present disclosure, optionally, the second processing unit obtains multiple target sequences corresponding to multiple target periods, respectively averages the sampling results located at the same relative position in the multiple target sequences to obtain multiple target sampling results, and combines the multiple target sampling results into an average target sequence. In this way, the measurement device can have higher accuracy.

[0011] In the measurement device involved in the first aspect of the present disclosure, optionally, the second processing unit constructs the in-phase component and the orthogonal component corresponding to the average target sequence based on the target response signal, thereby obtaining the target information based on the target sequence, and the in-phase component and the orthogonal component. In this case, the target information can be obtained based on the average target sequence, thereby effectively improving the accuracy of the measurement device.

[0012] In the measurement device involved in the first aspect of the present disclosure, optionally, the second processing unit obtains the amplitude of the in-phase component and the amplitude of the quadrature component based on the average target sequence, the in-phase component and the quadrature component, and obtains the target information based on the amplitude of the in-phase component and the amplitude of the quadrature component. Thus, the target information can be obtained based on the average target sequence.

[0013] In the measurement device involved in the first aspect of the present disclosure, optionally, the electrodes in the electrode array are in contact with the object to be imaged. In this case, it is convenient for the measurement unit to apply an excitation signal to the object to be imaged and to collect a response signal.

[0014] In the measurement device involved in the first aspect of the present disclosure, optionally, the target information is the amplitude of the fundamental frequency sinusoidal component in the target response signal. Thus, it is easy to obtain the target information.

[0015] The second aspect of the present disclosure provides a measurement method for electrical impedance imaging, characterized in that it includes: applying an excitation signal to an imaging object and measuring a response signal generated by the excitation signal, performing a first processing on the response signal to obtain a target response signal, and performing a second processing on the target response signal to obtain target information, wherein the first processing includes a primary amplification processing, a signal conversion processing, a primary filtering processing, a secondary amplification processing, a secondary filtering processing, and an analog-to-digital conversion processing, and the second processing includes sampling from the target response signal at a preset frequency within a target period to obtain a target sequence, and constructing an in-phase component and an orthogonal component corresponding to the target sequence based on the target response signal, thereby obtaining the target information based on the target sequence, and the in-phase component and the orthogonal component.

[0016] In the present disclosure, an excitation signal can be applied to the object to be imaged and a response signal can be measured at the same time, and the response signal can be processed for the first time and the second time in sequence to obtain 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.

[0017] In the measurement method involved in the second aspect of the present disclosure, optionally, multiple target cycles are sampled respectively to obtain multiple target sequences, the sampling results located at the same relative position in the multiple target sequences are averaged respectively to obtain multiple target sampling results, the multiple target sampling results are combined into an average target sequence, and the in-phase component and the orthogonal component corresponding to the average target sequence are constructed based on the target response signal, so as to obtain the target information based on the average target sequence, the in-phase 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.

[0018] According to the present disclosure, a measuring device for electrical impedance imaging and a measuring method thereof with higher accuracy and lower power consumption can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Detailed description of the invention is given in detail below.

[0020] Figure 2 is a circuit diagram showing a measuring unit and a first processing unit involved in an example of the present disclosure.

[0021] Figure 3 is a schematic diagram showing a measurement unit involved in an example of the present disclosure.

[0022] Figure 4 is a schematic diagram showing the structure of an electrode array involved in the example of the present disclosure.

[0023] FIG. 5 is a schematic diagram showing an application of an electrode array involved in an example of the present disclosure.

[0024] Figure 6 is a circuit diagram showing a first processing unit involved in an example of the present disclosure.

[0025] Figure 7 A circuit diagram of an equipotential point generating module according to an example of the present disclosure is shown.

[0026] Figure 8 is a flowchart illustrating a measurement method for electrical impedance imaging involved in an example of the present disclosure. DETAILED DESCRIPTION

[0027] Hereinafter, the preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same symbols are assigned to the same components, and repeated descriptions are omitted. In addition, the accompanying drawings are only schematic diagrams, and the ratio of the dimensions of the components or the shapes of the components may be different from the actual ones.

[0028] It should be noted that the terms "including" and "having" and any variations thereof in the present disclosure, such as a process, method, system, product or device that includes or has a series of steps or units, are not necessarily limited to those steps or units clearly listed, but may include or have other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0029] The present disclosure provides a measuring device for electrical impedance imaging (sometimes referred to as a measuring device). The measuring device 1 (see Figure 1 ) can be applied to electrical impedance imaging technology. According to the present disclosure, a measuring device 1 for electrical impedance imaging with a simple structure, high accuracy and low power consumption can be provided. For example, the measuring device 1 involved in the present disclosure can be a portable device. The measuring device 1 can be powered by a battery.

[0030] Figure 1 2 is a block diagram showing the structure of a measuring device 1 according to an example of the present disclosure. Figure 2 is a circuit diagram showing the measuring unit 110 and the first processing unit 210 involved in the example of the present disclosure.

[0031] For some examples, see Figure 1 The measuring device 1 may include a collection module 10 and a processing module 20 . The processing module 20 may be connected to the collection module 10 .

[0032] In some examples, the acquisition module 10 may be used to apply an excitation signal to the object to be imaged, and the acquisition module 10 may measure a response signal, wherein the response signal may be generated by the excitation signal.

[0033] In some examples, the object to be imaged may be an object having different resistance or resistivity distributions, such as a human body.

[0034] In some examples, the excitation signal may be a current or voltage signal that is safe relative 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 device 1 is capable of applying a square wave current signal to the object to be imaged, and is capable of acquiring a response voltage signal generated by the square wave current signal.

[0035] In some examples, the acquisition module 10 may include a measurement unit 110 and an excitation source 120 (see Figure 1 to Figure 3 ). The excitation source 120 may be connected to the measuring unit 110 and may provide an excitation signal to the measuring unit 110 .

[0036] Figure 3 is a schematic diagram showing a measurement unit 110 involved in an example of the present disclosure. Figure 4 FIG. 5 is a schematic diagram showing the structure of the electrode array 1110 involved in the example of the present disclosure. FIG.

[0037] In some examples, the measurement unit 110 may contact the object to be imaged. In some examples, the measurement unit 110 may include an electrode array 1110 including a plurality of electrodes (see Figure 3~5). In some examples, each electrode in the electrode array 1110 can be in contact with the object to be imaged. In this case, it is convenient for the measuring unit to apply an excitation signal to the object to be imaged, and it is convenient for the measuring unit to collect a response signal. In some examples, the measuring unit 110 can configure the electrodes in the electrode array 1110 on the object to be imaged in a manner of contacting the surface of the object to be imaged. In some examples, the electrodes in the electrode array 1110 can be arranged in sequence in a straight line. In some examples, the electrodes in the electrode array 1110 can be evenly distributed. In some examples, the electrode array 1110 can be arranged on the object to be imaged in a surrounding manner. In this case, it is convenient to obtain more comprehensive relevant information about the object to be imaged later. For example, the electrode array 1110 can be set on a flexible belt (such as a strap). In this case, medical staff can configure the flexible belt on the object to be imaged in a manner of surrounding the object to be imaged, and can make the electrodes distributed on the flexible belt contact the surface of the object to be imaged. For example, multiple electrodes in the electrode array 1110 can be arranged in sequence along the length direction of the flexible belt and evenly distributed on the flexible belt. Both ends of the flexible belt can have devices that cooperate with each other and are used for fixing. The flexible belt can be arranged on the object to be imaged in a manner of surrounding the object to be imaged by a fixing device. A plurality of electrodes on the flexible belt can contact the surface of the object to be imaged.

[0038] In some examples, the measurement unit 110 may apply an excitation signal to the object to be imaged. In some examples, the measurement unit 110 may apply an excitation signal to the object to be imaged through electrodes in the electrode array 1110 that are in contact with the object to be imaged.

[0039] In some examples, the measuring unit 110 may further include a first selecting subunit 1120 (see Figure 3 ). Thus, it is possible to facilitate the measurement device 1 to apply an excitation signal to the object to be imaged. In some examples, the first selection subunit 1120 can be used to select a number of electrodes from the electrode array 1110 as excitation electrodes. Among them, the excitation electrode can be an electrode used to apply an excitation signal to the object to be imaged. In some examples, the number of excitation electrodes can be two.

[0040] In some examples, the stimulation electrodes in electrode array 1110 can be variable. In some examples, as described above, electrode array 1110 can include multiple electrodes. For example, see Figure 4 , the multiple electrodes can be a starting electrode D1, an electrode D2, ..., a terminating electrode D16, etc.

[0041] In some examples, when the electrodes in the electrode array 1110 are arranged in a straight line, the starting electrode D1 and the ending electrode D16 may be the first electrode and the last electrode distributed along the length direction M in the electrode array 1110, respectively (see Figure 4 ). In some examples, the plurality of electrodes may include an electrode corresponding to any electrode. That is, the electrodes in the plurality of electrodes may correspond. Any electrode in the plurality of electrodes may be matched to an electrode corresponding thereto in the plurality of electrodes. In some examples, the first selection subunit 1120 may start from the starting electrode D1 and sequentially select two corresponding electrodes as excitation electrodes along the circumferential direction L or the longitudinal direction M of the electrode array 1110. In some examples, the two corresponding electrodes may be set by relevant technicians.

[0042] In some examples, the two corresponding electrodes may be two adjacent electrodes. The first selection subunit 1120 may select two adjacent electrodes as excitation electrodes. In some examples, the first selection subunit 1120 may start from the starting electrode D1 and sequentially select two adjacent electrodes as excitation electrodes along the circumferential direction L of the electrode array. For example, the first selection subunit 1120 may first select electrode D1 (i.e., starting electrode D1) and electrode D2 as excitation electrodes, and then may sequentially select electrode D2 and electrode D3, electrode D3 and electrode D4, etc. as excitation electrodes (see Figure 4 and Figure 5(a)).

[0043] In some other examples, the electrode array 1110 is arranged in a circle, and the two corresponding electrodes may be the two electrodes farthest from each other (see Figure 4 5(b)). For example, the first selection subunit 1120 may first select the electrode D1 and the electrode D9 as the excitation electrodes, and then may sequentially select the electrode D2 and the electrode D10, the electrode D3 and the electrode D11, etc. as the excitation electrodes.

[0044] In some examples, the first selection subunit 1120 may select several electrodes from the electrode array 1110 as excitation electrodes, and the excitation electrodes 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 several electrodes from the electrode array 1110 to apply a square wave current to the object to be imaged.

[0045] In some examples, after the measuring unit 110 applies an excitation signal to the object to be imaged, the measuring unit 110 may measure a response signal. Specifically, the measuring unit 110 may apply an excitation signal to the object to be imaged through an electrode in contact with the object to be imaged, and the excitation signal may generate a response signal through the object to be imaged, and the measuring unit 110 may measure the response signal through the electrode in contact with the object to be imaged.

[0046] In some examples, the measuring unit 110 may further include a second selecting subunit 1130 (see Figure 3 ). Thus, it is convenient for the measuring device 1 to obtain a response signal. In some examples, the second selection subunit 1130 can select several electrodes from the electrode array 1110 as measurement electrodes. Among them, the measurement electrode can be an electrode used to measure and obtain a response signal from the object to be imaged. In some examples, the number of measurement electrodes can be two. In some examples, the second selection subunit 1130 can select two other adjacent electrodes other than the excitation electrode from the electrode array 1110 as measurement electrodes. In some examples, the measurement electrodes in the electrode array 1110 can be variable. In some examples, the second selection subunit 1130 can start from the starting electrode D1 and select two adjacent electrodes other than the excitation electrode in sequence along the circumferential direction L of the electrode array as measurement electrodes. For example, if electrode D1 and electrode D9 are excitation electrodes, the second selection subunit 1130 can select electrode D2 and electrode D3, electrode D3 and electrode D4, electrode D4 and electrode D5, etc. in sequence as measurement electrodes. In some examples, the starting electrode D1 and the ending electrode D16 (i.e., electrode D16) can be regarded as two adjacent electrodes.

[0047] In some examples, the second selection subunit 1130 can select several electrodes from the electrode array 1110 as measurement electrodes, and the measurement unit 110 can obtain the response signal by measuring the measurement electrodes. For example, when a square wave current is applied to the object to be imaged, the second selection subunit 1130 can select two electrodes from the electrode array 1110 as measurement electrodes, and the measurement unit 110 can obtain the voltage (i.e., the response voltage signal) between corresponding positions on the object to be imaged (i.e., the positions where the two electrodes are in contact with the object to be imaged, respectively) through the measurement electrodes, and the voltage can be output as a response signal.

[0048] In some examples, after the selection of the measuring electrode has cycled from the starting electrode D1 to the ending electrode D16, the first selection subunit 1120 may replace the excitation electrode. In this case, the first selection subunit 1120 may sequentially select two corresponding electrodes as excitation electrodes along the circumferential direction L of the electrode array 1110. In other examples, the excitation signal may be an excitation current. When the excitation current passes through a zero point or has a constant phase delay with the zero point, the first selection subunit 1120 may replace the excitation electrode.

[0049] In some examples, starting from when the excitation electrode is replaced, the measurement unit 110 may start to collect the response signal using the measurement electrode after a predetermined time. In this case, the collected signal can be more accurate, which can effectively improve the accuracy of the measurement device 1. In some examples, the predetermined time can be set by relevant technicians.

[0050] In some examples, the acquisition module 10 may further include an excitation source 120. In some examples, the excitation source 120 may be connected to the measuring unit 110. In some examples, the excitation source 120 may provide an excitation signal to the measuring 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, etc. In some examples, relevant personnel may adjust or set the excitation signal sent by the excitation source 120. For example, relevant personnel may adjust or set the frequency, amplitude, type, etc. of the excitation signal sent 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 30KHz to 80KHz. For example, the excitation source 120 may generate a square wave current with a frequency of 50KHz.

[0051] In some examples, as described above, the measuring device 1 may further include a processing module 20 (see Figure 1 ). In some examples, the processing module 20 may be connected to the acquisition module 10 and receive the response signal for processing.

[0052] In some examples, the processing module 20 may include a first processing unit 210 and a second processing unit 220 (see Figure 1 ). The second processing unit 220 may be connected to the first processing unit 210 .

[0053] In some examples, the first processing unit 210 can be connected to the measurement unit 110 to receive the response signal. In some examples, the first processing unit 210 can receive the response signal and process it to obtain a target response signal.

[0054] Figure 6is a circuit diagram showing a first processing unit 210 involved in an example of the present disclosure.

[0055] In some examples, the first processing unit 210 may include a first operational amplifier 2110 and a second operational amplifier 2120 (see Figure 6 ). In some examples, the first operational amplifier 2110 and the second operational amplifier 2120 may each have an input terminal and an output terminal. In some examples, the input terminal of the first operational amplifier 2110 and the input terminal of the second operational amplifier 2120 may be respectively connected to 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 roughly formed as a follower structure. The positive phase input terminal of the first operational amplifier 2110 is connected to the measurement unit 110 to receive a response signal. The negative phase 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 roughly formed as a follower structure. The positive phase input terminal of the second operational amplifier 2120 is connected to the measurement unit 110 to receive a response signal. The negative phase 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 obtained by the measuring electrode can flow through the first operational amplifier 2110 and the second operational amplifier 2120 respectively, and the first operational amplifier 2110 and the second operational amplifier 2120 can buffer and amplify the response signal respectively. For example, the response signal obtained by the measuring unit 110 can be buffered and amplified by the first operational amplifier 2110 and the second operational amplifier 2120 respectively to obtain the first response signal and the second response signal (equivalent to the one-time amplification process described in the subsequent measurement method), that is, the response signal can flow through the first operational amplifier 2110 to obtain the first response signal, and the response signal can flow through the second operational amplifier 2120 to obtain the second response signal. As a result, it can be beneficial to obtain higher-precision information later.

[0056] In some examples, the first operational amplifier 2110 and the second operational amplifier 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 mega-ohms, etc. Thus, the influence of the contact impedance generated by the contact between the electrode and the skin can be effectively suppressed.

[0057] In some examples, the first processing unit 210 may further include a differential amplifier 2130 (see Figure 6). In some examples, the differential amplifier 2130 may have two input terminals (a positive input terminal and a negative input terminal) and an output terminal. In some examples, the output terminal of the first operational amplifier 2110 and the output terminal of the second operational amplifier 2120 may be connected to the input terminal of the differential amplifier 2130, respectively. For example, the output terminal of the first operational amplifier 2110 is connected to the positive input terminal of the differential amplifier 2130; the output terminal of the second operational amplifier 2120 is connected to the negative input terminal of the differential amplifier 2130. In this case, the first response signal and the second response signal may flow into the input terminal of the differential amplifier 2130, respectively, and may flow out from the output terminal of the differential amplifier 2130 to obtain a third response signal. In some examples, the third response signal may be a single-ended signal (equivalent to the signal conversion process described in the subsequent measurement method). Thus, the differential amplifier 2130 is capable of converting the first response signal and the second response signal into a third response signal.

[0058] In some examples, the differential amplifier 2130 may have a high common mode rejection ratio, thereby effectively suppressing power frequency interference and common mode interference such as electrode polarization voltage.

[0059] In some examples, the first processing unit 210 may further include a programmable gain amplifier 2140 (see Figure 6 ). In some examples, the programmable gain amplifier 2140 may have an input terminal and an output terminal. In some examples, the output terminal of the differential amplifier 2130 may be connected to the input terminal of the programmable gain amplifier 2140 via a resistor-capacitor DC isolation filter circuit. That is, a resistor-capacitor DC isolation filter circuit may be provided between the output terminal of the differential amplifier 2130 and the input terminal of the programmable gain amplifier 2140. However, the examples disclosed herein are not limited thereto. In some examples, the output terminal of the differential amplifier 2130 may be directly connected to the input terminal of the programmable gain amplifier 2140. That is, the third response signal may flow directly from the output terminal of the differential amplifier 2130 to the input terminal of the programmable gain amplifier 2140. In this case, the programmable gain amplifier 2140 is capable of adjusting the amplitude of the third response signal.

[0060] 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 terminal and a second connection terminal. The first resistor may have a third connection terminal and a fourth connection terminal. In some examples, the first connection terminal of the first capacitor may be connected to the output terminal of the differential amplifier 2130. The second connection terminal of the first capacitor may be connected to the input terminal 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.

[0061] In some examples, the third response signal can flow from the output end of the differential amplifier 2130 through the RC-DC blocking filter circuit to the input end of the programmable gain amplifier 2140 (equivalent to the primary filtering process described in the subsequent measurement method). In this case, the third response signal can flow through the RC-DC blocking filter circuit, thereby effectively filtering out the DC component in the third response signal.

[0062] In some examples, the third response signal flowing through the RC isolation filter circuit can flow in from the input of the programmable gain amplifier 2140. For example, the programmable gain amplifier 2140 may have a positive input and a negative input. The programmable gain amplifier 2140 may be roughly formed as a follower structure. The positive input of the programmable gain amplifier 2140 may be connected to the second connection end of the first capacitor. The negative input of the programmable gain amplifier 2140 may be connected to the output of the programmable gain amplifier 2140. In this case, the third response signal can flow in from the input of the programmable gain amplifier 2140, and can flow out from the output of the programmable gain amplifier 2140 to obtain a fourth response signal (equivalent to the secondary amplification process described in the subsequent measurement method). Thus, the amplitude of the third response signal can be adjusted.

[0063] In some examples, the first processing unit 210 may further include an analog-to-digital converter 2150 (see Figure 6 ). In some examples, the analog-to-digital converter 2150 may have an input terminal. In some examples, the output terminal of the programmable gain amplifier 2140 may be connected to the input terminal of the analog-to-digital converter 2150 via an anti-aliasing filter circuit. That is, an anti-aliasing filter circuit may be provided between the output terminal of the programmable gain amplifier 2140 and the input terminal of the analog-to-digital converter 2150. However, the examples of the present disclosure are not limited thereto. In some examples, the output terminal of the programmable gain amplifier 2140 may be directly connected to the input terminal of the analog-to-digital converter 2150. That is, the fourth response signal may flow directly from the output terminal of the programmable gain amplifier 2140 to the input terminal of the analog-to-digital converter 2150. In this case, the fourth response signal can be converted into a digital signal via the analog-to-digital converter 2150.

[0064] In some examples, the anti-aliasing filter 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 terminal of the second resistor may be connected to the input terminal 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.

[0065] In some examples, the fourth response signal can flow from the output of the programmable gain amplifier 2140 to the input of the analog-to-digital converter 2150 via the anti-aliasing filter circuit (equivalent to the secondary filtering process described later). In this case, the fourth response signal can flow through the anti-aliasing filter circuit, thereby effectively suppressing the influence of high-frequency harmonics and noise.

[0066] In some examples, the fourth response signal flowing through the anti-aliasing filter circuit can flow in from the input end of the analog-to-digital converter 2150, and the fourth response signal can obtain the target response signal (equivalent to the analog-to-digital conversion process described later) through the analog-to-digital converter 2150. In this case, the fourth response signal can be converted into a digital signal by the analog-to-digital converter 2150. Thus, it is convenient to obtain the target information later.

[0067] In some examples, as described above, the first processing unit 210 can be configured such that the inputs of the first operational amplifier 2110 and the second operational amplifier 2120 are respectively connected to the measuring unit 110, the outputs of the first operational amplifier 2110 and the second operational amplifier 2120 can be respectively connected to the inputs of the differential amplifier 2130, the output of the differential amplifier 2130 can be connected to the input of the programmable gain amplifier 2140 via a resistor-capacitor DC isolation filter circuit, and the output of the programmable gain amplifier 2140 can 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 subsequently acquired can be effectively improved through the first processing unit 210, the influence of noise can be effectively reduced, and the power consumption of the measuring device 1 can be effectively reduced.

[0068] In some examples, as described above, the processing module 20 may also include a second processing unit 220 (see Figure 1). In some examples, the second processing unit 220 can be connected to the first processing unit 210. In some examples, the second processing unit 220 can be connected to the first processing unit 210 through a transmission wire. For example, the analog-to-digital converter 2150 can have an output terminal. The second processing module 220 can be connected to the output terminal of the analog-to-digital converter 2150 to receive the target response signal. In other examples, the second processing unit 220 can be connected to the first processing unit 210 wirelessly. In some examples, the second processing unit 220 can receive the target response signal from the first processing unit 210 and process it to obtain the target information.

[0069] In some examples, as described above, the second processing unit 220 may receive a target response signal. In some examples, the second processing unit 220 may sample the target response signal to obtain multiple sampling results to form a target sequence. In some examples, the second processing unit 220 may sample the target response signal within a target period to obtain multiple sampling results to form a 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 obtain a target sequence. That is, the second processing unit 220 may sample the target response signal at every target time within the target period. In this case, the second processing unit 220 may obtain multiple sampling results within the target period, and the second processing unit 220 may form multiple sampling results into a target sequence. For example, the second processing unit 220 may sample the target response signal by continuous sampling at equal intervals with a time interval of T / N (i.e., the target time is T / N), and the second sampling module 220 may obtain N sampling results within one target period and form a sequence V. s (k). Wherein, T may be the period of the excitation signal, and k=0, 1, 2, ..., N-1. In some examples, the second processing unit 220 may collect data from the start time of the target period. However, the examples disclosed herein are not limited thereto. In some examples, the second processing unit 220 may collect data from other times of the target period.

[0070] In some examples, the second processing unit 220 can obtain multiple sampling results in each target period and respectively constitute multiple target sequences. Among them, each target period can correspond to a target sequence. In some examples, the sampling results of any two target sequences can be one-to-one corresponding. In some examples, the two corresponding sampling results can be respectively at the corresponding positions of their respective target periods. In other words, the time intervals between the two sampling results at the moment of their respective target periods and the moment when their respective target periods start can be equal. In some examples, the second processing unit 220 can average the sampling results at corresponding positions in multiple target sequences to obtain multiple target sampling results. In this case, the second processing unit 220 can group multiple target sampling results into an average target sequence. As a result, the measuring device 1 can have a higher accuracy.

[0071] In some examples, the second processing unit 220 may construct an in-phase component and an orthogonal component corresponding to a target sequence or an average target sequence based on the target response signal. In some examples, the target response signal may be a triangular wave signal or a square wave signal, etc., and the second processing unit 220 may construct an in-phase component and an orthogonal component of a base frequency corresponding to a target sequence or an average target sequence based on the target response signal. For example, the target response signal may be a square wave signal. A square wave signal may be expressed in the frequency domain as a weighted superposition of a sinusoidal signal of the same frequency and its odd harmonic signals. For example, a square wave signal may satisfy: Among them, A m It can be the amplitude of a square wave signal. In this case, if the target response signal is a square wave signal, the in-phase component of the fundamental frequency corresponding to the target sequence or the average target sequence can satisfy: The orthogonal components of the fundamental frequencies corresponding to the target sequence or the average target sequence can satisfy: However, the examples of the present disclosure are not limited thereto. In some examples, the target response signal may be a sinusoidal signal, and the second processing unit 220 may construct a target sequence or average the in-phase component and the orthogonal component corresponding to the target sequence based on the target response signal.

[0072] In some examples, the second processing unit 220 may obtain target information based on the target sequence (or average target sequence), and the in-phase component and the orthogonal component. In this case, the accuracy of the measurement device 1 can be effectively improved.

[0073] In some examples, the second processing unit 220 can obtain the amplitude of the in-phase component and the orthogonal component based on the target sequence (or average target sequence), and the in-phase component and the orthogonal component. Thus, the amplitude of the in-phase component and the amplitude of the orthogonal component can be obtained, which is convenient for subsequent acquisition of target information. In some examples, the second processing unit 220 can perform point multiplication of the target sequence (or average target sequence) with the in-phase component and the orthogonal component, respectively, to obtain the amplitude of the in-phase component and the orthogonal component. For example, if the target response signal is a square wave signal, the amplitude of the in-phase component can satisfy: The amplitude of the orthogonal components can satisfy: Where A is the amplitude of the fundamental frequency sinusoidal component in the target response signal and satisfies: A = 4A m π, φ are additional phase shifts caused by the fact that the sampling of the second processing unit 220 does not start from the beginning time (ie, time 0) of each target cycle.

[0074] In some examples, the second processing unit 220 can obtain target information based on the amplitude of the in-phase component and the amplitude of the quadrature component. Thus, the target information can be obtained. The target information can be used to reflect the electrical impedance information of the object to be imaged. For example, the second processing unit 220 can further obtain the amplitude of the fundamental frequency sinusoidal component corresponding to the target response signal based on the amplitude of the in-phase component and the quadrature component, and satisfy: Wherein, N represents the number of samples in the target period. The amplitude of the fundamental frequency sinusoidal component can be used as target information. Thus, it is easy to obtain target information.

[0075] In some examples, the measuring device 1 may further include a display module (not shown) for displaying the resistivity distribution of the object to be imaged. In some examples, the display module may receive 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 current amplitude factor that is a constant, and the display module may display according to the electrical impedance information.

[0076] Figure 7 is a circuit diagram showing an equipotential point generating module 30 according to an example of the present disclosure.

[0077] In some examples, the measuring device 1 can adopt a power supply mode of multiple power supplies (e.g., dual power supplies). In this case, the grounding in each module of the measuring device 1 can be "grounding" in the usual sense. That is, the grounding in each module of the measuring device 1 can be actual grounding. For example, the fourth connection terminal of the first resistor can be actually grounded. The eighth connection terminal of the second capacitor can be actually grounded.

[0078] In some examples, the current excitation device 1 can be powered by a single power supply. In this case, the grounding in each module of the measuring device 1 can be connected to a "virtual ground" (i.e., an "equipotential point"). In other words, the grounding in each module of the current excitation device 1 can be a virtual ground. For example, the fourth connection terminal of the first resistor can be connected to the equipotential point. The eighth connection terminal of the second capacitor can be connected to the equipotential point.

[0079] In some examples, the voltage of the equipotential point may be any voltage between the power supply voltage and 0 V. For example, the voltage of the equipotential point may be half of the power supply voltage.

[0080] In some examples, the isoelectric point can be provided by the isoelectric point generation module 30. In some examples, such as Figure 7 As shown, the equipotential point generating 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 power supply voltage may be represented by VCC. One end of the fourth resistor 320 may be connected to a 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 be connected to each other. Figure 7 The power supply voltage VCC is divided to obtain the equipotential point voltage.

[0081] In some examples, such as Figure 7 As shown, one end of the third capacitor 330 can be connected to the non-inverting input terminal of the operational amplifier 340. The other end of the third capacitor 330 can be actually grounded. In some examples, the third capacitor 330 can be a filter capacitor. In this case, the noise in the equipotential point voltage can be filtered out by the third capacitor 330.

[0082] In some examples, such as Figure 7 As shown, the negative phase input terminal of the operational amplifier 340 can be connected to the output terminal of the operational amplifier 340. In this case, the operational amplifier 340 can form an impedance conversion circuit, thereby increasing the driving capability of the equipotential point voltage.

[0083] In some examples, the output end of the operational amplifier 340 is the equipotential point. For example, under the condition of a single power supply, the output end of the operational amplifier 340 can be used to connect to the fourth connection end of the first resistor; the output end of the operational amplifier 340 can be used to connect to the eighth connection end of the second capacitor.

[0084] Figure 8 is a flowchart illustrating a measurement method for electrical impedance imaging involved in an example of the present disclosure.

[0085] In the embodiment of the present disclosure, a measurement method for electrical impedance imaging is provided (see Figure 8 ). In this embodiment, see Figure 8 , the measurement method for electrical impedance imaging may include applying an excitation signal to the imaging object and measuring the response signal at the same time (step S10); the measurement method for electrical impedance imaging may include processing the response signal for a first time to obtain a target response signal (step S20); processing the target response signal for a second time to obtain target information (step S30). According to the measurement method disclosed in the present invention, the accuracy of the measurement method can be effectively improved, and the power consumption of the measurement method can be effectively reduced. In some examples, the acquisition and processing of the imaging object, the excitation signal and the response signal in the measurement method can refer to the above description of the imaging object, the excitation signal and the response signal.

[0086] In step S10 , as described above, an excitation signal is applied to the object to be imaged and a response signal is measured simultaneously.

[0087] In some examples, step S10 can be implemented using the acquisition module 10. For example, the acquisition module 10 in the measurement device 1 can be used to apply an excitation signal to the object to be imaged, and the response signal can be measured simultaneously. The excitation signal can be a current or voltage that is safe relative to the object to be imaged. The response signal can be a voltage or current generated after the excitation signal is applied to the object to be imaged.

[0088] In step S20, as described above, the response signal is first processed to obtain a target response signal.

[0089] In some examples, the acquisition and processing of the target response signal in the measurement method can refer to the above-mentioned target response signal. For details, refer to the processing of the response signal by the first processing unit 210. In some examples, the first processing may include a first amplification process, a signal conversion process, a first filtering process, a second amplification process, a second filtering process, and an analog-to-digital conversion process. In some examples, step S20 can be implemented using the first processing unit 210. In some examples, the response signal can be processed for the first time using the first processing unit 210 to obtain the target response signal.

[0090] In step S30, as described above, the target response signal is processed for a second time to obtain target information. In some examples, the acquisition and processing of target information in the measurement method can refer to the above description of the target information. In some examples, the second processing may include sampling from the target response signal at a preset frequency within the target period to obtain a target sequence, and constructing an in-phase component and an orthogonal component corresponding to the target sequence based on the target response signal, thereby obtaining target information based on the target sequence, and the in-phase component and the orthogonal component. In some examples, step S30 can be implemented using the second processing unit 220. In some examples, the response signal can be processed for a second time using the second processing unit 220 to obtain target information.

[0091] In some examples, in the measurement method, multiple target cycles can be sampled separately to obtain multiple target sequences. In some examples, the sampling results at the same relative position in multiple target sequences can be averaged to obtain multiple target sampling results. Multiple target sampling results can be combined into an average target sequence. Target information can be obtained by averaging the target sequence. In this case, the accuracy of the measurement method can be effectively improved. In some examples, the sampling results at the same relative position in multiple target sequences can be equal to the time interval of the moment of obtaining the sampling results in each target cycle relative to the start time of their respective target cycles. For details, please refer to the above description of the average target sequence.

[0092] Although the present disclosure is specifically described above in conjunction with the accompanying drawings and examples, it is to be understood that the above description does not limit the present disclosure in any form. Those skilled in the art may modify and change the present disclosure as needed without departing from the essential spirit and scope of the present disclosure, and these modifications and changes all fall within the scope of the present disclosure.

Claims

1. A processing module for response signals of electrical impedance imaging, characterized in that: The response signal is generated by applying an excitation signal to the object to be imaged. The processing module includes: a first processing unit, and a second processing unit connected to the first processing unit. The first processing unit is configured to receive the response signal and process it to obtain a target response signal. The first processing unit includes a first operational amplifier, a second operational amplifier, a differential amplifier, a programmable gain amplifier, and an analog-to-digital converter. The response signal is obtained by the first operational amplifier to obtain a first response signal, and the response signal is obtained by the second operational amplifier to obtain a second response signal. The first response signal and the second response signal are converted into a third response signal via the differential amplifier. The third response signal is obtained by the programmable gain amplifier to obtain a fourth response signal. The fourth response signal is converted by The analog-to-digital converter obtains the target response signal; the second processing unit is configured to receive the target response signal and sample from the target response signal at a preset frequency within a target period to obtain a target sequence, and construct an in-phase component and an orthogonal component corresponding to the target sequence based on the target response signal, thereby obtaining target information based on the target sequence, and the in-phase component and the orthogonal component. The first processing unit also includes a resistor-capacitor DC isolation filter circuit, and the third response signal flows from the output end of the differential amplifier to the input end of the programmable gain amplifier via the resistor-capacitor DC isolation filter circuit. The first processing unit also includes an anti-aliasing filter circuit, and the fourth response signal flows from the output end of the programmable gain amplifier to the input end of the analog-to-digital converter via the anti-aliasing filter circuit.

2. The processing module according to claim 1, characterized in that The second processing unit obtains multiple target sequences corresponding to multiple target periods, respectively averages the sampling results located at the same relative position in the multiple target sequences to obtain multiple target sampling results, combines the multiple target sampling results into an average target sequence, and constructs an in-phase 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 in-phase component and the orthogonal component.

3. The processing module according to claim 1, characterized in that: The target period corresponds to one period of the excitation signal.

4. The processing module according to claim 1, characterized in that: The RC-DC blocking filter circuit includes a first capacitor and a first resistor, wherein the first connection end of the first capacitor is connected to the output end of the differential amplifier, the second connection end of the first capacitor is connected to the input end of the programmable gain amplifier, the third connection end of the first resistor is connected to the second connection end of the first capacitor, and the fourth connection end of the first resistor is grounded.

5. The processing module according to claim 1, characterized in that: The target response signal is a triangular wave signal or a square wave signal.

6. The processing module according to claim 1, characterized in that: The second processing unit is connected to the first processing unit via a transmission wire or wirelessly.

7. The processing module according to claim 1, characterized in that: The second processing unit performs point multiplication on the target sequence with the in-phase component and the orthogonal component respectively to obtain the amplitude of the in-phase component and the amplitude of the orthogonal component, and acquires the target information based on the amplitude of the in-phase component and the amplitude of the orthogonal component.

8. The processing module according to claim 1, characterized in that: The target information is the amplitude of the fundamental frequency sinusoidal component in the target response signal, and the target information is used to reflect the electrical impedance information of the object to be imaged.

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