This application claims the benefit of Taiwan application Serial No. 110147909, filed Dec. 21, 2021, the disclosure of which is incorporated by reference herein in its entirety.
The disclosure relates in general to an electrophysiological signal measurement system, an electrophysiological signal adjustment method and an electrode assembly.
As people pay more and more attention to the requirements of health management, various kinds of physiological signal measuring devices are constantly being introduced in sports, fitness, health care, nursing, long-term care and other fields.
However, when the coupled electrophysiological signal measuring device is used, the correctness of the signal is often affected by the use of low pressure. Especially when the interface impedance between the skin and the electrode sheet is greater, the baseline of the Electromyography signal (EMG signal) will become more unstable.
In addition, for a subject with muscle injury, the amplitude of the EMG signal will become weak, and it is difficult to measure and interpret.
Furthermore, when the electrophysiological signal is detected at moving state, noise is likely to be generated, and these noises make the interpretation of the electrophysiological signal difficult.
Therefore, an electrophysiological signal adjustment method is required, in order to be able to adjust the electrophysiological signal adaptively for various situations and improve the measurement accuracy.
According to one embodiment, an electrophysiological signal measurement system is provided. The electrophysiological signal measurement system includes an electrode assembly, a variation adjustment device and a signal processing device. The electrode assembly is configured to receive an electrophysiological signal, a first electrical characteristic value and a second electrical characteristic value. The variation adjustment device includes a comparison unit and a searching unit. The comparison unit is configured to receive the first electrical characteristic value and the second electrical characteristic value, and determine whether a difference between the first electrical characteristic value and the second electrical characteristic value is greater than a threshold. The searching unit is configured to search for a plurality of amplitude calibration ratios corresponding to a plurality of frequencies when the difference between the first electrical characteristic value and the second electrical characteristic value is greater than the threshold. The signal processing device is configured to calibrate the electrophysiological signal according to the amplitude calibration ratios corresponding to the frequencies.
According to another embodiment, an electrophysiological signal adjustment method is provided. The electrophysiological signal adjustment method includes the following steps. An electrophysiological signal is received. A first electrical characteristic value and a second electrical characteristic value are received. Whether a difference between the first electrical characteristic value and the second electrical characteristic value is greater than a threshold is determined. A plurality of amplitude calibration ratios corresponding to a plurality of frequencies is searched when the difference between the first electrical characteristic value and the second electrical characteristic value is greater than the threshold. The electrophysiological signal is calibrated according to the amplitude calibration ratios corresponding to the frequencies.
According to an alternative embodiment, an electrode assembly is provided. The electrode assembly includes a first measuring electrode, a first ring electrode, a first surrounding electrode, a second measuring electrode, a second ring electrode and a second surrounding electrode. The first ring electrode surrounds the first measuring electrode. The first surrounding electrode surrounds the first ring electrode. The first measuring electrode and the second measuring electrode are configured to receive an electrophysiological signal. A location of the first measuring electrode is different from a location of the second measuring electrode. The second ring electrode surrounds the second measuring electrode. The second surrounding electrode surrounds the second ring electrode.
In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
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According to the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2, the electrophysiological signal measurement system 100 can decide whether to calibrate the electrophysiological signal ExG1 to obtain a calibrated electrophysiological signal ExG1*.
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The first measuring electrode P01 and the second measuring electrode P02 are used to receive the electrophysiological signal ExG1. The first ring electrode P11 and the first surrounding electrode P12 are used to receive the first electrical characteristic value ECV1. The second ring electrode P21 and the second surrounding electrode P22 are used to receive the second electrical characteristic value ECV2. The location of the first measuring electrode P01 is different from the location of the second measuring electrode P02.
The first ring electrode P11 surrounds the first measuring electrode P01. The first surrounding electrode P12 surrounds the first ring electrode P11. The second ring electrode P21 surrounds the second measuring electrode P02. The second surrounding electrode P22 surrounds the second ring electrode P21. The insulation material M0 is disposed among the first measuring electrode P01, the second measuring electrode P02, the first ring electrode P11, the first surrounding electrode P12, the second ring electrode P21 and the second surrounding electrode P22. The first ring electrode P11 and the first surrounding electrode P12 are preferably arranged concentrically, and the shape is not limited, such as concentric circles, concentric rectangles, concentric polygons, etc. The areas of the first ring electrode P11 and the first surrounding electrode P12 are substantially equal. The second ring electrode P21 and the second surrounding electrode P22 are preferably arranged concentrically, and the shape is not limited, such as concentric circles, concentric rectangles, concentric polygons, etc. The areas of the second ring electrode P21 and the second surrounding electrode P22 are substantially equal. If the electrodes are arranged concentrically and the areas are similar, the impedance can be reduced and the accuracy of the measured capacitance value can be increased.
Through the design of the aforementioned electrode assembly 110, the first ring electrode P11 and the first surrounding electrode P12 can measure the first electrical characteristic value ECV1 at the location of the first measuring electrode P01. The second ring electrode P21 and the second surrounding electrode P22 can measure the second electrical characteristic value ECV2 at the location of the second measuring electrode P02. Once the relationship between the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2 changes, it means that the electrophysiological signal ExG1 received by the first measuring electrode P01 and the second measuring electrode P02 also changes, so the electrophysiological signal measurement system 100 can determine whether the electrophysiological signal ExG1 needs to be calibrated to obtain the calibrated electrophysiological signal ExG1* (shown in
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The variation adjustment device 140 includes a comparison unit 141 and a searching unit 142. The signal processing device 170 includes a decomposition unit 171, a calibration unit 172 and an integration unit 173. The variation adjustment device 140 performs characteristic value comparison through the comparison unit 141, and performs data search through the searching unit 142. The signal processing device 170 performs signal decomposition through the decomposition unit 171, performs individual calibrations through the calibration unit 172, and finally performs integration through the integration unit 173 to obtain the final calibration result. The operation of the aforementioned components will be described in detail through the flow chart below.
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Next, in step S107, the first ring electrode P11 and the first surrounding electrode P12 of the electrode assembly 110 receive the first electrical characteristic value ECV1, and the second ring electrode P21 and the second surrounding electrode P22 of the electrode assembly 110 receives the second electrical characteristic value ECV2. The first electrical characteristic value ECV1 and the second electrical characteristic value ECV2 are, for example, capacitance values or resistance values.
Then, in step S108, the comparison unit 141 receives the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2, and determines whether a difference DF1 between the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2 is greater than a threshold TH1. If the difference DF1 between the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2 is greater than the threshold TH1, then the process proceeds to step S109; if the difference DF1 between the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2 is not greater than the threshold TH1, then the process proceeds to step S101. Generally speaking, when the user has a large dynamic action, it may cause that the first component G1 or the second component G2 of the electrode assembly 110 is not completely attached to the skin, and the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2 may be inconsistent matched. Once the difference DF1 is greater than the threshold TH1, it is necessary to calibrate the electrophysiological signal ExG1, so the process proceeds to steps S109 to S110. The difference DF1 is, for example, the ratio between a differential signal and a common mode signal generated internally by the comparison unit 141 after receiving the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2. The threshold TH1 is, for example, 0.02.
In the step S109, the searching unit 142 searches for the amplitude calibration ratios RTij corresponding to the frequencies Fj according to the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2. In this step, the searching unit 142 performs searching, for example, according to an average value Ci of the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2. For example, please referring to the following table I, when the average value Ci is “C1”, the amplitude calibration ratios RTij corresponding to the frequencies Fj which are “F1 to Fn” are “RT11 to RT1n.”
Please referring to the following table two again, when the average value Ci is “C5”, the amplitude calibration ratios RTij corresponding to the frequencies Fj which are “F1 to Fn” are “RT51 to RT5n.”
Afterwards, in step S110, the signal processing device 170 calibrates the electrophysiological signal ExG1 according to the amplitude calibration ratios RTij corresponding to the frequencies Fj. Please refer to
In the step S1101, the composition unit 171 of the signal processing device 170 decomposes the electrophysiological signal ExG1 to obtain a plurality of electrophysiological sub-signals ExG1j corresponding to the frequencies Fj. Each of the electrophysiological sub-signals ExG1j has an amplitude variation Aj. Each of the amplitude variations Aj is, for example, the difference between the highest amplitude point and the lowest amplitude point, or, the difference between the center point of the AC wave signal and the highest amplitude point or the lowest amplitude point. As shown in Table III below, the electrophysiological signal ExG1 can be decomposed into a plurality of electrophysiological sub-signals ExG1j, such as “ExG11, ExG12, ExG1n”, whose corresponding frequencies Fj and corresponding amplitude variations Aj are “F1, F2, . . . , Fn” and “A1, A2, . . . , An” respectively.
In one embodiment, the decomposition unit 171 decomposes the electrophysiological signal ExG1 by a signal decomposition algorithm. The signal decomposition algorithm is a combination of a Short time Fourier transform (STFT) and a Power Spectral Density Function (PSDF) algorithm, or the signal decomposition algorithm is a wavelet transform algorithm, or the signal decomposition algorithm is an Empirical Mode Decomposition (EMD) algorithm.
Then, in the step S1102, the calibration unit 172 calibrates the amplitude variations Aj of the electrophysiological sub-signals ExG1j according to the amplitude calibration ratios RTij corresponding to the frequencies Fj respectively. Please refer to
In one embodiment, for different electrophysiological sub-signals ExG1j, the amplitude calibration ratios RTij corresponding to the amplitude variations Aj may not be totally the same. The calibration unit 172 calibrates all of the electrophysiological sub-signals ExG1j.
Next, in step S1103, the integration unit 173 uses the inverse Fourier transform algorithm (frequency domain to time domain) to integrate the electrophysiological sub-signals ExG1j calibrated by the calibration unit 172 and obtains the calibrated electrophysiological signal ExG1*.
According to the above-described embodiment, after receiving the electrophysiological signal ExG1, the variation adjustment device 140 obtains the amplitude calibration ratios RTij. The signal processing device 170 can calibrate the electrophysiological signal ExG1 according to the amplitude calibration ratios RTij to obtain the calibrated electrophysiological signal ExG1*. The calibrated electrophysiological signal ExG1* overcomes the mismatch of electrical characteristic values, so that the electrophysiological signal measurement system 100 can obtain highly accurate measurement results even when the user has a large dynamic action.
The aforementioned embodiment carries out the calibration of the electrophysiological signal ExG1 through the comparison of the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2. In another embodiment, whether the electrical characteristic value has changed can be detected before the above comparison to save power. Please refer to
Whether the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2 need to be compared and whether the electrophysiological signal ExG1 needs to be calibrated are determined according to the third electrical characteristic value ECV3 to obtain the calibrated electrophysiological signal ExG1*.
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The third ring electrode P31 is disposed between the first ring electrode P11 and the second ring electrode P21. The third surrounding electrode P32 surrounds the third ring electrode P31. The third ring electrode P31 and the third surrounding electrode P32 are used to receive the third electrical characteristic value ECV3. The insulation material M0 is disposed among the first measuring electrode P01, the second measuring electrode P02, the first ring electrode P11, the first surrounding electrode P12, the second ring electrode P21, the second surrounding electrode P22, the third ring electrode P31 and the third surrounding electrode P32. The third ring electrode P31 and the third surrounding electrode P32 are preferably arranged concentrically, and the shape is not limited, such as concentric circles, concentric rectangles, concentric polygons, etc. The areas of the third ring electrode P31 and the third surrounding electrode P32 are substantially equal. When the electrodes are arranged concentrically and the area is similar, the impedance can be reduced and the accuracy of the measured capacitance value can be increased.
Through the design of the aforementioned electrode assembly 210, the third ring electrode P31 and the third surrounding electrode P32 can measure the third electrical characteristic value ECV3 between the first measuring electrode P01 and the second measuring electrode P02. Once the third electrical characteristic value ECV3 changes greatly, it means that the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2 may also change, so it can be determined whether the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2 are needed to be compared according to the third electrical characteristic value ECV3.
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According to the aforementioned embodiment, only when the third electrical characteristic value ECV3 has a large change, the comparison unit 141 performs the comparison between the first electrical characteristic value ECV1 and the second electrical characteristic value ECV2, so as to save power consumption.
In addition, when the muscle group to be measured or the area is small, the aforementioned electrode assemblies 110, 210 can be integrated. Please refer to
Furthermore, for the subject with muscle injury or the elderly, the amplitude of the electrophysiological signal ExG1 will be weak, and it is difficult to measure and interpret. Please refer to
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In step S103, the amplifying unit 452 of the front-end circuit conditioning device 450 amplifies the electrophysiological signal ExG1 by a first gain ratio Mg1. The first gain ratio Mg1 is, for example, 2 times.
In step S104, the amplifying unit 452 of the front-end circuit conditioning device 450 amplifies the electrophysiological signal ExG1 by a second gain ratio Mg2. The second gain ratio Mg2 is, for example, 3 times.
The amplified electrophysiological signal ExG1e is inputted to the signal processing device 170 for performing the calibration in the steps S105 to S110.
According to the above-mentioned embodiment, when the user has a large dynamic action, and the electrode assembly 110 is not completely attached to the skin, the calibration of the electrophysiological signal ExG1 can be performed. Furthermore, for subjects with muscle injury, the electrophysiological signal ExG1 can also compensate appropriately. Therefore, the electrophysiological signal ExG1 can be adjusted adaptively for various situations, which greatly improves the measurement accuracy.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.
Number | Date | Country | Kind |
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110147909 | Dec 2021 | TW | national |