Electrocardiographic data detection device and electrocardiographic data detection method

Abstract

To provide electrocardiographic data detection device and detection method capable of selecting a differential signal suitable for the detection of an electrocardiogram out of a plurality of differential signals.SOLUTION: An electrocardiographic data detection device (100) includes: a plurality of electrodes 110 disposed opposed to a human body; a differential signal generation unit (131A) for generating differential signals of signals of two electrodes of the plurality of electrodes, which generates a plurality of the differential signals from the signals of a plurality of sets of the two electrodes; and a differential signal selection unit (133A) for selecting a plurality of differential signals suitable for the measurement of the cardiac beat out of the plurality of differential signals generated by the differential signal generation unit. The differential signal selection unit selects a first differential signal the most suitable for the measurement of the cardiac beat out of the plurality of differential signals generated by the differential signal generation unit, and a second differential signal the most suitable for the measurement of the cardiac beat of the plurality of differential signals generated from the signals of the remaining plurality of electrodes excluding a pair of first electrodes for outputting an original signal of the first differential signal, from the plurality of electrodes.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an electrocardiogram data detection device and an electrocardiogram data detection method. [Background technology]

[0002] Conventionally, there has been an electrocardiogram measurement device that includes a pair of insulated measurement electrodes to be placed facing each other on the human body in an electrically insulated state, and a measurement circuit that detects a change in voltage caused by capacitive coupling between each of the insulated measurement electrodes and the human body, amplifies the difference between the two voltages detected by both the insulated measurement electrodes, and outputs the amplified difference as an electrocardiogram waveform signal (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-082938 A Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, conventional electrocardiogram measurement devices include two insulated measurement electrodes and measure an electrocardiogram based on the difference in voltage between the two insulated measurement electrodes (differential signal). However, they do not use more electrodes to obtain multiple differential signals and select from the multiple differential signals a differential signal suitable for measuring an electrocardiogram.

[0005] It is therefore an object of the present invention to provide an electrocardiogram data detection device and an electrocardiogram data detection method capable of selecting a differential signal suitable for detecting electrocardiogram data from a plurality of differential signals. [Means for solving the problem]

[0006] An electrocardiogram data detection device according to an embodiment of the present disclosure includes a plurality of electrodes arranged facing the human body, a differential signal generation unit that generates a differential signal of signals of two of the plurality of electrodes, the differential signal generation unit generating a plurality of the differential signals from signals of multiple sets of the two electrodes, and a differential signal selection unit that selects a plurality of differential signals suitable for measuring a heartbeat from the plurality of differential signals generated by the differential signal generation unit, the differential signal selection unit selecting a first differential signal that is optimal for measuring a heartbeat from the plurality of differential signals generated by the differential signal generation unit, and a second differential signal that is optimal for measuring a heartbeat from the plurality of differential signals generated from signals of the remaining plurality of electrodes excluding a pair of first electrodes that output the original signal of the first differential signal from the plurality of electrodes. Effect of the Invention

[0007] It is possible to provide an electrocardiogram data detection device and an electrocardiogram data detection method capable of selecting a differential signal suitable for detecting electrocardiogram data from a plurality of differential signals. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of a configuration of an electrocardiogram data detection device according to an embodiment. [Diagram 2] FIG. 13 is a diagram showing an example of the signal-to-noise ratios of 28 differential signals obtained from eight electrodes. [Diagram 3] FIG. 13 is a diagram showing an example of the signal-to-noise ratios of 28 differential signals obtained from eight electrodes. [Figure 4] 11 is a flowchart illustrating an example of processing executed by an MCU of the electrocardiogram data detection device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment to which the electrocardiogram data detection device and the electrocardiogram data detection method of the present disclosure are applied will be described.

[0010] <Embodiment> 1 is a diagram showing an example of the configuration of an electrocardiogram data detection device 100 according to an embodiment. The electrocardiogram data detection device 100 includes electrodes 110, a buffer circuit 115, an ADC (Analog to Digital Converter) 120, an MCU (Micro Controller Unit) 130, and an I / F (Interface) driver 140. The ADC 120, the MCU 130, and the I / F driver 140 constitute an ECU (Electronic Control Unit) 150. The ECU 150 is mounted on a vehicle, for example, and is connected to a higher-level device via an in-vehicle network, for example.

[0011] The electrocardiogram data detected by the electrocardiogram data detection device 100 is data indicating electrical activity of the heart, and includes data including an electrocardiogram waveform, etc., or heartbeat data indicating a heartbeat (heartbeat interval, or a heart rate obtained from the heartbeat interval) obtained based on the electrocardiogram data. In this embodiment, an example in which the heartbeat interval is obtained will be described.

[0012] As an example, the electrocardiogram data detection device 100 is a device that detects electrocardiogram data of a driver seated in a driver's seat 10 of a vehicle. Fig. 1 shows the driver's seat 10 of a vehicle. However, the electrocardiogram data detection device 100 may be a device that detects electrocardiogram data of a passenger other than the driver seated in the driver's seat 10 of a vehicle, and may be applied to a device other than a vehicle, such as a chair installed in a conference room or a chair installed in a movie theater.

[0013] A plurality of electrodes 110 are provided inside a seat 10 of a driver's seat of a vehicle. More specifically, the plurality of electrodes 110 are provided on the underside of the seat surface and backrest of the seat 10, and face the buttocks and back of a driver seated in the seat 10. As an example, a configuration in which eight electrodes 110 are provided in the seat 10 will be described. However, the number of electrodes 110 is not limited to eight. The number of electrodes 110 is preferably four or more, and more preferably six or more.

[0014] The electrodes 110 are capacitively coupled to the opposing body of the driver through the surface layer or clothing of the seat 10, and are intended to measure an electrical signal generated in the human body during cardiac activity as an induced signal generated in the electrodes 110. Therefore, by detecting a voltage difference between two of the eight electrodes 110, it is possible to detect a potential difference between two points on the body. The electrodes 110 are connected to the ECU 150 via a buffer circuit 115 such as a voltage follower circuit. The voltage signal input from the buffer circuit 115 to the ECU 150 represents the voltage of each electrode 110.

[0015] The ADC 120 is provided between the buffer circuit 115 and the MCU 130. The ADC 120 samples the voltage signal input from the buffer circuit 115 at sufficiently short time intervals, such as several msec, to convert the signal into a digital signal and output the digital signal to the MCU 130.

[0016] In this embodiment, the ADC 120 operates constantly and outputs to the electrocardiogram data detection device 100, but it may be configured to perform conversion for 5 seconds or more intermittently.

[0017] The MCU 130 includes a calculation unit 130A, a control unit 130B, and a communication I / F 130C. The MCU 130 is realized by a computer including a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), an input / output interface, an internal bus, and the like.

[0018] The calculation unit 130A has a differential signal generation unit 131A, a signal determination unit 132A, a differential signal selection unit 133A, a heartbeat detection unit 134A, a heartbeat determination unit 135A, and an output selection unit 136A. The signal determination unit 132A, the differential signal selection unit 133A, the heartbeat detection unit 134A, and the output selection unit 136A have memories 132A1, 133A1, 134A1, and 136A1, respectively.

[0019] The calculation unit 130A, the control unit 130B, and the communication I / F 130C, and the differential signal generation unit 131A, the signal determination unit 132A, the differential signal selection unit 133A, the heartbeat detection unit 134A, the heartbeat determination unit 135A, and the output selection unit 136A inside the calculation unit 130A are shown as functional blocks of the functions of the program executed by the MCU 130. Also, memories 132A1, 133A1, 134A1, and 136A1 are functional representations of the memories of the MCU 130. Note that the MCU 130 may have memories other than those shown here, but these are omitted in FIG. 1.

[0020] <Arithmetic section 130A> The calculation unit 130A generates heartbeat data such as heartbeat intervals based on the voltage value output from the ADC 120, and outputs the data to the communication I / F 130C.

[0021] Here, a form will be described in which the differential signal selection unit 133A selects three differential signals when selecting multiple differential signals suitable for measuring the heart rate. However, the number of multiple differential signals suitable for measuring the heart rate is not limited to three, and is preferably equal to or less than half the number of electrodes, and may be, for example, two or four.

[0022] In addition, here, when the differential signal selection unit 133A selects the differential signal optimal for measuring the heart rate from among the multiple differential signals, a form in which the differential signal selection unit 133A selects the differential signal with the highest S / N ratio from among the multiple differential signals will be described as an example. However, the differential signal selection unit 133A may select the differential signal optimal for measuring the heart rate from among the multiple differential signals using an index other than the S / N ratio.

[0023] The differential signal generating unit 131A selects two different voltage values ​​from eight voltage values ​​output from the ADC 120 within a predetermined time period, for example, five seconds, and calculates a differential signal. Since there are eight voltage values ​​on the subtracting side and eight voltage values ​​on the subtracted side, simply calculating all the differential signals will result in 8×8=64 differential signals. However, the differential value of the same electrode is zero, so there is no point in calculating the differential signal. In addition, when the subtracting side and the subtracted side are swapped, the calculated differential value simply has the opposite sign to that before the swap, and can be considered as equivalent electrocardiogram data, so there is no point in calculating the differential signal both before and after the swap. For this reason, in this embodiment, two different voltages are selected from the eight voltage values ​​to generate a differential signal, generating 8C2=(8*7) / 2=28 differential signals. Each differential signal is identified by a combination of eight electrodes 110. The differential signal is evaluated by the ratio of the signal level to the noise level (SN ratio). The differential signal generating unit 131A outputs the differential signal to the differential signal selecting unit 133A and the signal determining unit 132A.

[0024] The 5-second data output from ADC 120 to be calculated as a differential signal and the next 5-second data to be calculated as a differential signal may be continuous or separated by a predetermined time interval. Also, the data may be partially overlapping (2.5 seconds from 2.5 seconds to 5.0 seconds), such as the first differential signal data being calculated by calculating the signal output from ADC 120 between 0 and 5 seconds, and the second differential signal data being calculated by calculating the signal output from ADC 120 between 2.5 and 7.5 seconds.

[0025] The signal determination unit 132A determines whether the 28 differential signals input from the differential signal generation unit 131A are suitable for detecting electrocardiogram data by calculating the S / N ratio of the 28 differential signals, and outputs the determination result to the differential signal selection unit 133A and the output selection unit 136A. The determination result of the signal determination unit 132A represents, for example, data in which the 28 differential signals are arranged in order from the highest S / N ratio to the lowest S / N ratio, and the electrode number corresponding to the S / N ratio. The calculation logic for calculating the S / N ratio by the signal determination unit 132A is stored in the memory 132A1, and the determination result of the signal determination unit 132A is also stored in the memory 132A1.

[0026] The differential signal selection unit 133A stores the determination result input from the signal determination unit 132A and the 28 differential signals input from the differential signal generation unit 131A in the memory 133A1. Based on the determination result input from the signal determination unit 132A, the differential signal selection unit 133A selects three differential signals suitable for measuring the heartbeat from the 28 differential signals input from the differential signal generation unit 131A, and outputs them to the heartbeat detection unit 134A. The method of selecting the three differential signals is stored in the memory 133A1, and the selection method will be described in detail later.

[0027] Heartbeat detection unit 134A stores the three difference signals input from difference signal selection unit 133A in memory 134A1. Heartbeat detection unit 134A records the time at which a heartbeat (heart beat) occurs based on each difference signal input from difference signal selection unit 133A, and if the time at which the previous heartbeat occurred is recorded, records the time interval between that time and the previous heartbeat.

[0028] Incidentally, electrocardiogram data is generated by electrical signals that occur with the contraction of the atria and ventricles of the heart, and is composed of P waves, QRS waves, T waves, etc., and the time when the heartbeat occurs in each differential signal is mainly determined to be the peak position of the QRS wave, which is the largest signal. However, in reality, the waveform of the electrocardiogram data measured varies depending on the attachment positions of the electrodes to the heart, so the time when the heartbeat occurs is determined based on a predetermined calculation logic stored in memory 134A1.

[0029] The heartbeat detection unit 134A outputs heartbeat data corresponding to three difference signals indicating the time when the heartbeat occurs or the time interval to the heartbeat determination unit 135A and the output selection unit 136A. Note that the heartbeat data corresponding to one difference signal is composed of multiple data corresponding to the number of heartbeats in five seconds.

[0030] The heartbeat determination unit 135A obtains the time interval at which heartbeats occur when the heartbeat data input from the heartbeat detection unit 134A is the time at which a heartbeat occurs, and when the heartbeat data input from the heartbeat detection unit 134A is the time interval at which a heartbeat occurs, it determines whether this time interval is within a range that should be regarded as heartbeat data, and outputs the determination result to the output selection unit 136A. As a specific example of a method for determining whether a range should be regarded as heartbeat data, if there is a discontinuous change in the time interval that is equal to or greater than a threshold, it is not regarded as heartbeat data, etc.

[0031] The output selection unit 136A outputs to the communication I / F 130C the heartbeat data that is most suitable for measuring the heartbeat among the data that can be regarded as a heartbeat, based on the three heartbeat data input from the heartbeat detection unit 134A, the judgment result input from the heartbeat judgment unit 135A, and the S / N ratio calculated by the signal judgment unit 132A.

[0032] The control unit 130B controls the operation of the differential signal generating unit 131A, the differential signal selecting unit 133A, the heartbeat detecting unit 134A, and the output selecting unit 136A of the calculation unit 130A as described above, and the operation of the communication I / F 130C. At the timing of generating the next differential signal, the differential signal generating unit 131A does not generate 28 differential signals. It generates only three differential signals suitable for measuring the heartbeat, which correspond to the electrode numbers stored in the memory 132A1 of the signal determining unit 132A. This is performed as long as the heartbeat determining unit 135A can obtain data that can be regarded as the heartbeat. If it becomes impossible to obtain data that can be regarded as the heartbeat, it generates 28 differential signals again, and repeats this operation as long as the electrocardiogram data detecting device 100 is running.

[0033] Therefore, compared to generating 28 difference signals each time, it is possible to increase the calculation speed and also reduce the burden on the calculator and memory.

[0034] The communication I / F 130C transmits the heart rate data input from the output selection unit 136A to a higher-level device of the ECU 150 via an in-vehicle network driven by an I / F driver 140.

[0035] The heart rate data is used, for example, to evaluate the driver's level of tension or stress, or his / her drowsiness.

[0036] <Comparative electrocardiogram data detection method and electrocardiogram data detection method according to the embodiment> Next, a method for selecting a differential signal performed by the differential signal selection unit 133A will be described. Note that, assuming that three differential signals are selected, the electrocardiogram data detection method in the comparative electrocardiogram data detection device and the electrocardiogram data detection method in this embodiment will be described.

[0037] 2 and 3 are diagrams showing an example of the SNR of 28 differential signals obtained from the eight electrodes 110. In FIG.

[0038] Here, first, an electrocardiogram data detection method in the electrocardiogram data detection device will be described with reference to FIG. 2 and FIG.

[0039] 2 shows a signal indicating the magnitude of the difference between the voltage values ​​of any two of the eight electrodes 110, that is, a signal corresponding to an electrocardiogram waveform, evaluated based on the S / N ratio to see whether it is appropriate as an electrocardiogram waveform. As mentioned above, 8C2=(8*7) / 2=a total of 28 differential signals are generated. In FIG. 2, the calculated values ​​are shown in the upper right area.

[0040] In FIG. 2, the numbers 1 to 8 shown in the horizontal and vertical directions indicate the numbers of the eight electrodes 110. In the following, the differential signal will be indicated as differential signal (1-7). The differential signal (1-7) is the magnitude of the differential signal between the signal of electrode 110 number 1 and the signal of electrode 110 number 7. The same applies to the other electrodes. The first number corresponds to the electrode number in the horizontal direction in FIGS. 2 and 3, and the subsequent numbers correspond to the electrode number in the vertical direction. The SN ratio is, for example, a ratio calculated by using the average voltage value measured over a predetermined time as the denominator (noise level) and the peak value as the numerator (signal level).

[0041] Heartbeat data is obtained by acquiring signals from eight electrodes 110 for five seconds, determining 28 differential signals for five seconds, and detecting an electrocardiogram signal from the differential signals. In the comparative electrocardiogram data detection method, as an example, the top three differential signals (7-1, 7-2, 7-4) with the highest S / N ratios are selected, and the electrocardiogram signal is detected using the selected three differential signals. If an electrocardiogram signal cannot be detected using the three differential signals, the selection is repeated.

[0042] Incidentally, better detection results can be obtained when the electrodes 110 are in close proximity to the human body under pressure via the surface of clothing or a seat. For this reason, in the comparative electrocardiogram data detection device, one of the electrode pairs (two electrodes 110) that output the original signals of the top three difference signals with good signal quality is often the electrode 110 that is common to the top three difference signals. In Fig. 2, the seventh electrode 110 is the common electrode 110.

[0043] For this reason, when the human body moves, if the proximity between the common electrode 110 and the human body changes and the good measurement state is lost, the heart rate cannot be measured using the top three differential signals. As a result, the heart rate data during the period when the heart rate could not be measured cannot be acquired, and it becomes necessary to acquire the 28 differential signals again and select the top three differential signals, which causes a problem that the overall measurement time becomes longer.

[0044] Fig. 3 shows an example of 28 differential signals obtained when the distance between electrode 7 and the human body is wider than when the 28 differential signals shown in Fig. 2 are obtained. The signal-to-noise ratios of the differential signals (7-1, 7-2, 7-3, 7-4, 7-5, 7-6, 8-7) of the electrode pairs including electrode 7 are low, and in particular, the signal-to-noise ratios of the top three differential signals (7-1, 7-2, 7-4) in Fig. 2 are significantly lower than those in Fig. 2.

[0045] Thus, in the comparative electrocardiogram data detection method, if the human body moves and good measurement conditions are lost in the electrode pair including the common electrode 110, the heart rate cannot be measured using the three differential signals.

[0046] The electrocardiogram data detection device 100 of the embodiment solves such a problem and provides an electrocardiogram data detection device and an electrocardiogram data detection method capable of selecting a differential signal suitable for electrocardiogram detection from a plurality of differential signals.

[0047] <Electrocardiogram Data Detection Method of the Embodiment> The differential signal selection unit 133A selects three differential signals suitable for measuring the heart rate from the 28 differential signals generated by the differential signal generation unit 131A according to the method described below. The 28 differential signals are an example of a plurality of differential signals, and have, for example, the SNR shown in FIG.

[0048] <How to select the first differential signal> The differential signal selection unit 133A selects the differential signal (7-1) with the highest S / N ratio from the 28 differential signals generated by the differential signal generation unit 131A. In this way, the differential signal selection unit 133A selects the differential signal (7-1) with the highest S / N ratio from the 28 differential signals as the first differential signal. The differential signal (7-1) with the highest S / N ratio is an example of a first differential signal that is optimal for measuring heart rate. The first and seventh electrodes 110 that output the two original signals of the differential signal (7-1) are an example of a pair of first electrodes.

[0049] <How to select the second differential signal> The differential signal selection unit 133A selects the differential signal (5-2) with the maximum S / N ratio from 15 differential signals generated from the signals of the remaining electrodes 110 (six electrodes, 2 to 6 and 8) excluding the pair of electrodes 110 (1 and 7) that output the two original signals of the differential signal (7-1) from the 28 electrodes 110. In this way, the differential signal selection unit 133A selects the differential signal (5-2) as the second differential signal. The differential signal (5-2) is an example of a second differential signal that is optimal for measuring the heart rate. The second and fifth electrodes 110 that output the two original signals of the differential signal (5-2) are an example of a pair of second electrodes.

[0050] The differential signal (5-2) selected second in the electrocardiogram data detection method of the embodiment is obtained from electrodes 2 to 6 and 8 110 excluding electrodes 110 1 and 7 related to the differential signal (7-1) selected first, and is therefore a differential signal that is not affected even if the proximity state between electrode 110 1 or 7 and the human body changes.

[0051] In order to realize the first differential signal selection method and the second differential signal selection method, the number of the plurality of electrodes 110 needs to be at least four or more.

[0052] <How to select the third differential signal> The differential signal selection unit 133A selects the differential signal (4-3) with the maximum S / N ratio from among the multiple, specifically, six differential signals (4C2=(4*3) / 2=6) generated from the signals of the remaining multiple electrodes 110 (four electrodes: 3, 4, 6, and 8) excluding the first and seventh electrodes 110 that output the two original signals of the differential signal (7-1) and the second and fifth electrodes 110 that output the original signal of the differential signal (5-2) from the 28 electrodes 110. In this way, the differential signal selection unit 133A selects the differential signal (4-3) as the third differential signal. The differential signal (4-3) is an example of a third differential signal that is optimal for measuring heart rate.

[0053] The third selected differential signal (4-3) in the electrocardiogram data detection method of the embodiment is obtained from four electrodes 110, namely, electrodes 110 no. 3, 4, 6 and 8, excluding electrodes 110 no. 1 and 7 related to the first selected differential signal (1-7) and electrodes 110 no. 2 and 5 outputting the original signal of the second selected differential signal (2-5). Therefore, the differential signal is not affected even if the proximity of electrodes 110 no. 1, 2, 5 or 7 to the human body changes.

[0054] As described above, the electrocardiogram data detection method of the embodiment selects three differential signals suitable for measuring heartbeats from the 28 differential signals. Compared to the comparative electrocardiogram data detection method that selects the top three differential signals with the highest S / N ratios, it is possible to select differential signals that are less susceptible to changes in the proximity between the eight electrodes 110 and the human body.

[0055] In order to realize the first differential signal selection method, the second differential signal selection method, and the third differential signal selection method, the number of the plurality of electrodes 110 needs to be at least six or more.

[0056] In the method of this embodiment, when the state shown in Figure 3 occurs, the S / N ratio of the differential signal selected for the first selected differential signal (7-1) drops significantly to 2.4, but the S / N ratio of the second selected differential signal (5-2) is 4.7, and the S / N ratio of the third selected differential signal (4-3) is 4.0, so the heart rate can be detected and there is no need to re-obtain differential signals for all electrodes as in the comparative electrocardiogram data detection method.

[0057] <Modification of the method for selecting the third difference signal> Furthermore, when selecting a differential signal as the third differential signal, the following method may be used instead of the above-mentioned method.

[0058] The differential signal selection unit 133A identifies four electrodes 110 (1, 2, 5, 7), including the first and seventh electrodes 110 that output the original signal of the first selected differential signal (7-1) and the second and fifth electrodes 110 that output the original signal of the second selected differential signal (5-2).The differential signal selection unit 133A then identifies differential signals (1-2, 1-5, 1-7, 2-5, 2-7, 5-7) obtained from a combination of two electrodes 110 out of the four identified electrodes 110 (1, 2, 5, 7). Furthermore, the differential signal selection unit 133A selects the differential signal (7-4) with the maximum S / N ratio from the remaining differential signals, excluding the differential signals (2-1, 5-1, 5-2, 7-1, 7-2, 7-5) obtained from a combination of two of the identified four (1st, 2nd, 5th, 7th) electrodes 110, from the 28 differential signals generated by the differential signal generation unit 131A. The differential signal (7-4) is an example of a third differential signal that is optimal for measuring the heart rate.

[0059] In this method, when selecting the third differential signal, the difference between the electrode pair including only one of the four electrodes 110 (1, 2, 5, 7) between the electrodes 110 No. 1 and No. 7 that output the original signal of the first selected differential signal (7-1) and the electrodes 110 No. 2 and No. 5 that output the original signal of the second selected differential signal (5-2) was excluded in the selection, but can be restored. Here, an example of an electrode pair including only one of the four electrodes 110 (1, 2, 5, 7) is the differential signal (7-4), which includes one of the electrodes 110 No. 1 and No. 7 that output the original signal of the first selected differential signal (7-1).

[0060] In this modified example, the signal-to-noise ratio of the differential signal (7-4) selected third when the state shown in FIG. 3 occurs is 2.4, which is not suitable for detecting heartbeats, but is effective when there is little change in the proximity state between the four electrodes 110 (1, 2, 5, 7) and the human body.

[0061] That is, in the modified method of selecting the third differential signal, when selecting the third differential signal, an electrode pair including only one of the four electrodes 110 (1, 2, 5, 7) that output the original signals of the first and second selected differential signal (7-1) and differential signal (5-2) is restored, so that when there is little change in the proximity state between the four electrodes 110 (1, 2, 5, 7) and the human body, a differential signal with a higher S / N ratio can be selected.

[0062] In order to realize the first differential signal selection method, the second differential signal selection method, and the modified example of the third differential signal selection method, the number of the multiple electrodes 110 needs to be at least five or more.

[0063] <Flowchart> FIG. 4 is a flowchart showing an example of processing executed by the MCU 130 of the electrocardiogram data detection device 100. As shown in FIG.

[0064] When the process starts, the differential signal generating unit 131A generates a differential signal representing the differences between the eight voltage values ​​output from the ADC 120 (step S1). The differential signal is transmitted to the differential signal selecting unit 133A and the signal determining unit 132A. Note that, as an example, it is sufficient to perform measurements for a predetermined time (e.g., 5 seconds) using the eight electrodes 110, and if a satisfactory measurement result is not obtained, the measurement can be repeated.

[0065] The signal determination unit 132A generates a determination result representing data in which the 28 differential signals input from the differential signal generation unit 131A are arranged in order from highest S / N ratio to lowest S / N ratio (step S2). The determination result represents the quality of the 28 differential signals, with a higher S / N ratio indicating a better differential signal for measuring heart rate.

[0066] The differential signal selection unit 133A selects three differential signals suitable for measuring the heartbeat from the 28 differential signals based on the determination result of the signal determination unit 132A (step S3). The three differential signals suitable for measuring the heartbeat are selected as described with reference to Fig. 2. The selected differential signals are output to the heartbeat detection unit 134A.

[0067] The heartbeat detector 134A detects the heartbeat based on each differential signal input from the differential signal selector 133A (step S4). Heartbeat data representing the detected heartbeat is output to the heartbeat determiner 135A and the output selector 136A.

[0068] Based on the heartbeat data input from the heartbeat detection unit 134A, the heartbeat determination unit 135A determines whether or not the data should be regarded as heartbeat data, and outputs the determination result to the output selection unit 136A (step S5).

[0069] Based on the three pieces of heartbeat data input from the heartbeat detection unit 134A and the determination result input from the heartbeat determination unit 135A, the output selection unit 136A outputs the heartbeat data that is most suitable for measuring the heartbeat among the data considered to be the heartbeat data to the communication I / F 130C (step S6). If the heartbeat determination unit 135 determines that data that is considered to be heartbeat data is acquired, at the next heartbeat measurement timing, the differential signal is generated in step S1 only for the electrodes selected by the differential signal selection unit 133A, and steps S2 and S3 are omitted and the process jumps to step S4. Note that the electrodes for which the differential signal is generated in step S1 may be only those electrodes determined to be heartbeat data by the differential signal selection unit 133A and step S5.

[0070] Furthermore, in this embodiment, the differential signal is generated in step S1 only for the electrodes selected by the differential signal selection unit 133A, but it is also possible to perform AD conversion by the ADC 120 at the timing of measuring the next heartbeat only for the electrodes selected by the differential signal selection unit 133A.

[0071] If the heartbeat determination unit 135 determines that no data recognized as heartbeat data has been acquired, the operation from step S1 is repeated at the next heartbeat measurement timing.

[0072] The heart rate data may be output to the communication I / F 130C at a predetermined time interval, for example. The predetermined time interval may be selectable from a plurality of time intervals.

[0073] <Effects> The electrocardiogram data detection device 100 includes a plurality of electrodes 110 arranged opposite to the human body, a differential signal generating unit 131A that generates a differential signal between signals of two electrodes 110 among the plurality of electrodes 110, the differential signal generating unit 131A generating a plurality of differential signals from signals of a plurality of pairs of two electrodes 110, and a differential signal selecting unit 133A that selects a plurality of differential signals suitable for measuring a heartbeat from the plurality of differential signals generated by the differential signal generating unit 131A, and the differential signal selecting unit 133A selects a first differential signal optimal for measuring a heartbeat from the plurality of differential signals generated by the differential signal generating unit 131A, and a second differential signal optimal for measuring a heartbeat from the plurality of differential signals generated from the remaining plurality of electrodes 110 excluding a pair of electrodes 110 that outputs the original signal of the first differential signal from the plurality of electrodes 110. The second differential signal is obtained from the remaining electrodes 110 excluding the electrodes 110 related to the first differential signal, and is therefore less susceptible to influence even if the proximity state between the electrodes 110 related to the first differential signal and the human body changes.

[0074] Therefore, it is possible to provide an electrocardiogram data detection device 100 capable of selecting a differential signal suitable for detecting electrocardiogram data from among a plurality of differential signals.

[0075] The differential signal selection unit 133A may select a third differential signal that is optimal for measuring a heartbeat from a plurality of differential signals generated from the signals of the remaining plurality of electrodes 110 excluding a pair of electrodes 110 that output the original signal of the first differential signal and a pair of electrodes 110 that output the original signal of the second differential signal from the plurality of electrodes 110. The third differential signal is obtained from the remaining electrodes 110 excluding the four electrodes 110 that output the original signals of the first differential signal and the second differential signal, and is therefore a differential signal that is not affected even if the proximity state between the four electrodes 110 that output the original signals of the first differential signal and the second differential signal and the human body changes. Therefore, it is possible to provide an electrocardiogram data detection device 100 that can select three differential signals that are optimal for detecting electrocardiogram data from a plurality of differential signals.

[0076] The differential signal selection unit 133A may select a third differential signal that is optimal for measuring a heartbeat from the remaining multiple differential signals generated by the differential signal generation unit 131A, excluding differential signals obtained from two of the four electrodes 110, the pair of electrodes 110 that outputs the original signal of the first differential signal and the pair of electrodes 110 that outputs the original signal of the second differential signal. Since an electrode pair including only one of the four electrodes 110 that output the original signals of the first differential signal and the second differential signal is restored, a differential signal with a higher SN ratio can be selected when there is little change in the proximity state between the four electrodes 110 and the human body. Therefore, it is possible to provide an electrocardiogram data detection device 100 that can select three differential signals suitable for detecting electrocardiogram data from multiple differential signals.

[0077] Furthermore, the differential signal suitable for measuring the heart rate may be evaluated by the S / N ratio, making it possible to easily evaluate the quality of the differential signal based on the S / N ratio.

[0078] Furthermore, the first differential signal optimal for measuring the heart rate may be the differential signal having the highest S / N ratio among the multiple differential signals generated by the differential signal generating unit 131A. By selecting the differential signal having the highest S / N ratio among all the multiple differential signals as the first differential signal, it is possible to provide an electrocardiogram data detection device 100 that can easily select the first differential signal suitable for detecting electrocardiogram data from the multiple differential signals.

[0079] Furthermore, the second differential signal optimal for measuring the heart rate may be a differential signal having the maximum S / N ratio among multiple differential signals generated from the signals of the remaining multiple electrodes 110 excluding the pair of electrodes 110 that output the original signal of the first differential signal from the multiple electrodes 110. By selecting, as the second differential signal, a differential signal having the maximum S / N ratio among multiple differential signals generated from the signals of the remaining multiple electrodes 110 excluding the pair of electrodes 110 that output the original signal of the first differential signal from all of the multiple electrodes 110, it is possible to provide an electrocardiogram data detection device 100 that can easily select the first differential signal and the second differential signal suitable for detecting electrocardiogram data from the multiple differential signals.

[0080] Furthermore, the third differential signal optimal for measuring the heart rate may be the differential signal having the maximum S / N ratio among the multiple differential signals generated from the signals of the remaining multiple electrodes 110. It is possible to provide an electrocardiogram data detection device 100 that can easily select the third differential signal suitable for detecting electrocardiogram data based on the S / N ratio of the multiple differential signals generated from the signals of the remaining multiple electrodes 110.

[0081] Furthermore, the third differential signal optimal for measuring the heart rate may be the differential signal having the highest S / N ratio among the remaining differential signals. It is possible to provide an electrocardiogram data detection device 100 that can easily select the third differential signal optimal for detecting electrocardiogram data based on the S / N ratios of the multiple differential signals generated from the signals of the remaining multiple electrodes 110.

[0082] Furthermore, the number of the electrodes 110 may be at least five or more. It is possible to provide an electrocardiogram data detection device 100 capable of selecting a first differential signal and a second differential signal suitable for detecting electrocardiogram data from a plurality of differential signals obtained from signals of at least five or more electrodes 110.

[0083] The number of the electrodes 110 may be at least seven or more. It is possible to provide an electrocardiogram data detection device 100 capable of selecting a first differential signal, a second differential signal, and a third differential signal suitable for detecting electrocardiogram data from a plurality of differential signals obtained from signals of at least five or more electrodes 110.

[0084] The electrocardiogram data detection method includes an electrocardiogram data detection device 100 including a plurality of electrodes 110 arranged facing the human body, a differential signal generation unit 131A that generates a differential signal of signals of two of the plurality of electrodes 110, the differential signal generation unit 131A generating a plurality of differential signals from signals of multiple pairs of two electrodes 110, and a differential signal selection unit 133A that selects a plurality of differential signals suitable for measuring the heartbeat from the plurality of differential signals generated by the differential signal generation unit 131A, the differential signal selection unit 133A selecting a first differential signal optimal for measuring the heartbeat from the plurality of differential signals generated by the differential signal generation unit 131A, and selecting a second differential signal optimal for measuring the heartbeat from a plurality of differential signals generated from signals of the remaining plurality of electrodes 110 excluding a pair of electrodes 110 that output the original signal of the first differential signal from the plurality of electrodes 110. The second differential signal is obtained from the remaining electrodes 110 excluding the electrode 110 related to the first differential signal, and is therefore not affected even if the proximity state between the electrode 110 related to the first differential signal and the human body changes.

[0085] Therefore, it is possible to provide an electrocardiogram data detection method capable of selecting a differential signal suitable for detecting electrocardiogram data from among a plurality of differential signals.

[0086] The above describes an exemplary embodiment of the electrocardiogram data detection device and electrocardiogram data detection method of the present disclosure. However, the present disclosure is not limited to the specifically disclosed embodiments, and various modifications and variations are possible without departing from the scope of the claims. [Explanation of symbols]

[0087] 100 Electrocardiogram data detection device 110 electrodes 115 Buffer Circuit 120 ADC 130 MCU 130A calculation section 131A Differential signal generation section 132A Signal judgment section 133A Differential signal selection section 134A Heart Rate Detector 135A Heart Rate Detector 136A Output selection section 132A1, 133A1, 134A1, 136A1 Memory 130B Control section 130C Communication I / F 140 I / F driver

Claims

1. A plurality of electrodes arranged facing the human body; a differential signal generating unit that generates a differential signal of signals of two electrodes among the plurality of electrodes, the differential signal generating unit generating a plurality of the differential signals from signals of a plurality of pairs of the two electrodes; a differential signal selection unit that selects a plurality of differential signals suitable for measuring a heart rate from the plurality of differential signals generated by the differential signal generation unit; Including, The differential signal selection unit a first differential signal that is optimal for measuring a heart rate from among the plurality of differential signals generated by the differential signal generating unit; Among the plurality of differential signals generated from the signals of the remaining plurality of electrodes excluding a pair of first electrodes that output the original signal of the first differential signal from the plurality of electrodes, a second differential signal optimal for measuring a heart rate is selected; Select an electrocardiogram data detection device.

2. 2. The electrocardiogram data detection device of claim 1, wherein the differential signal selection unit selects a third differential signal that is optimal for measuring a heart rate from among the multiple differential signals generated from the signals of the remaining multiple electrodes excluding a pair of first electrodes that output an original signal of the first differential signal and a pair of second electrodes that output the original signal of the second differential signal from the multiple electrodes.

3. 2. The electrocardiogram data detection device according to claim 1, wherein the differential signal selection unit selects a third differential signal that is optimal for measuring a heart rate from among the remaining multiple differential signals generated by the differential signal generation unit, excluding differential signals obtained from two of four electrodes, namely a pair of first electrodes that output an original signal of the first differential signal and a pair of second electrodes that output the original signal of the second differential signal.

4. 4. The electrocardiogram data detection device according to claim 1, wherein the differential signal suitable for measuring the heart rate is evaluated by a signal-to-noise ratio.

5. 4. The electrocardiogram data detection device according to claim 1, wherein the first differential signal optimal for measuring the heart rate is a differential signal having a maximum signal-to-noise ratio among the plurality of differential signals generated by the differential signal generating unit.

6. The electrocardiogram data detection device according to any one of claims 1 to 3, wherein the second differential signal optimal for measuring the heart rate is a differential signal having the largest signal-to-noise ratio among the multiple differential signals generated from the signals of the remaining multiple electrodes excluding a pair of first electrodes that output the original signal of the first differential signal from the multiple electrodes.

7. 3. The electrocardiogram data detection device according to claim 2, wherein the third differential signal optimal for measuring the heart rate is a differential signal having a maximum S / N ratio among the plurality of differential signals generated from the signals of the remaining plurality of electrodes.

8. 4. The electrocardiogram data detection device according to claim 3, wherein the third differential signal optimum for measuring the heart rate is a differential signal having a maximum S / N ratio among the remaining plurality of differential signals.

9. The electrocardiogram data detection device according to claim 1 , wherein the number of the plurality of electrodes is at least five or more.

10. The electrocardiogram data detection device according to claim 2 , wherein the number of the plurality of electrodes is at least seven or more.

11. A plurality of electrodes arranged facing the human body; a differential signal generating unit that generates a differential signal of signals of two electrodes among the plurality of electrodes, the differential signal generating unit generating a plurality of the differential signals from signals of a plurality of pairs of the two electrodes; a differential signal selection unit that selects a plurality of differential signals suitable for measuring a heart rate from the plurality of differential signals generated by the differential signal generation unit; In an electrocardiogram data detection device including: The differential signal selection unit: selecting a first differential signal that is optimal for measuring a heart rate from the plurality of differential signals generated by the differential signal generating unit; A method for detecting electrocardiogram data, comprising the steps of: selecting a second differential signal that is optimal for measuring a heartbeat from among a plurality of differential signals generated from signals of the remaining plurality of electrodes excluding a pair of first electrodes that output the original signal of the first differential signal from the plurality of electrodes.

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