JP2011200268A - Biological information acquiring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biological information acquiring apparatus capable of stably detecting electrocardiographic signals especially when myoelectric noise is carried in measuring electrocardiographic signals.SOLUTION: The biological information acquiring apparatus includes: an electrode array 18 including a plurality of electrodes 10-16 brought into contact with a subject; electrocardiogram specifying means for measuring electrocardiographic R-waves of the electrocardiographic signals of the subject and specifying a plurality of combinations of electrodes to acquire electrocardiographic R-waves from the plurality of electrodes 10-16; electrocardiogram measuring means for measuring electrocardiographic R-waves of the electrocardiographic signals of the subject; a polarity detecting means for finding the polarity of the electrocardiographic R-waves when myoelectric noise is not present in the electrocardiographic signals; correlation value detecting means for finding correlation values of the elctrocradiographic signals according to the combinations of the electrodes 10-16 within the electrode array 18 when myoelectric noise is present in the electrocardiographic signals; and addition/subtraction processing determining means for determining a combination of electrocardiographic signals and the addition/subtraction process from the polarity of the electrocrdiographic R-waves and the correlation values.

Description

  The present invention relates to a biological information acquisition apparatus.

  As a conventional biometric information acquisition apparatus, it is disclosed regarding the measurement of an electrocardiogram signal in the upper arm. In the present invention, an electrode for taking an electrocardiogram and an electrode for removing noise generated from muscles are separately provided, and the ECG (electrocardiogram) signal is detected from a human body where it is difficult to detect an ECG (electrocardiogram) signal. It has been proposed to remove myoelectric noise present in a signal (see, for example, Patent Document 1). Also, body motion noise having a relatively low frequency and myoelectric noise having a relatively high frequency are detected using a plurality of electrodes having different areas in contact with the subject, and the myoelectric noise is passed through an HPF (high pass filter). It is proposed to remove myoelectric noise by calculating only the ECG signal and subtracting it from the measured ECG signal (see, for example, Patent Document 2).

Special table 2007-504917 gazette JP 2006-231020 A

  However, in Patent Document 1, the myoelectric noise detected as described above and the myoelectric noise superimposed on the ECG signal are not always the same, and there is a possibility that the effect cannot be obtained. Further, in Patent Document 2, the myoelectric potential of myoelectric noise detected by this method is not the same as the myoelectric potential that is actually a problem. Therefore, even if the myoelectric noise is removed by the differential amplifier, the effect may be small.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 An electrocardiographic R wave of an electrocardiographic signal of the subject is measured by differentially detecting an electrode array including a plurality of electrodes that are in contact with the subject and a potential between the electrodes of the electrode array. By differentially detecting the potential of the electrocardiogram specifying means for specifying a plurality of electrode combinations capable of taking an electrocardiogram R wave from the plurality of electrodes, and the combination of the electrodes in the electrode array specified by the electrocardiogram specifying means An electrocardiogram measuring means for measuring an electrocardiogram R wave of the electrocardiogram signal of the subject, and when there is no myoelectric noise of the electrocardiogram signal based on a measurement result of the electrocardiogram R wave by the electrocardiograph measurement means A combination of electrodes in the electrode array when there is myoelectric noise of the electrocardiogram signal based on the polarity detection means for determining the polarity of the electrocardiogram R wave and the measurement result of the electrocardiogram R wave by the electrocardiogram measurement means Correlation value detection for obtaining the correlation value of the ECG signal And an addition / subtraction process determination means for determining a combination of the electrocardiogram signals and an addition / subtraction process thereof from the polarity of the electrocardiogram R wave obtained by the polarity detection means and the correlation value obtained by the correlation value detection means. A biological information acquisition apparatus characterized by the above.

  According to this, an electrocardiogram signal measured from a plurality of electrodes is determined by calculating a calculation method based on a correlation value between the polarity of the electrocardiogram R wave and a signal having myoelectric noise, so that the myoelectric noise can be removed. A combination can be selected, and an electrocardiographic signal with less myoelectric noise can be obtained. In other words, regarding the detection of an electrocardiogram signal, stable signal detection can be performed by adding the electrocardiogram signals measured from a plurality of electrodes so that the amplitude of the electrocardiogram R wave is maximized. Therefore, regarding the measurement of an electrocardiogram signal, a biological information acquisition apparatus capable of stably detecting an electrocardiogram signal even when there is myoelectric noise is provided.

  Specifically, the correlation between the detection signals in A and B during operation is positive with respect to electrode combinations A and B of the positive and negative signals of the electrocardiographic R wave when there is no myoelectric noise. Then, by calculating AB, the electrocardiogram R wave is added and the electromyogram noise is removed (the ECG R wave has the same sign and the correlation between the detection signals of A and B may be negative. ).

  Application Example 2 The biometric information acquisition apparatus, wherein the addition / subtraction process determination unit is executed in real time.

  According to this, since the generation state of myoelectric noise changes due to muscle activity, the above calculation is executed in real time, and the combination of electrodes and the calculation of myoelectric noise removal are performed, thereby causing various operations. EMG noise can be removed.

  Application Example 3 In the biological information acquisition apparatus, the subject moves by detecting a mechanical quantity with a vibrator that is attached to at least a part of the body of the subject and vibrates based on a drive signal. A dynamic quantity detection unit used for determining whether or not the medium is present, and a motion analysis unit that analyzes a signal from the mechanical quantity detection unit, the motion analysis unit at each time of the movement of the subject A file is generated in which a database of the used electrode combinations and calculation methods is generated, and the electrode combination is selected based on a signal from the mechanical quantity detection unit using the generated file. Biological information acquisition device.

  According to this, a sensor such as an acceleration sensor or a gyro sensor as a mechanical quantity detection unit is attached, the movement of the subject is estimated, the predicted movement, the combination of electrodes used at that time, and the calculation method are recorded. Create a database. When the database is accumulated, an electrode combination is selected based on signals from various sensors. For example, in walking and running, the movement of the upper arm is monotonous, and myoelectric noise is generated in accordance with the movement. From the database and sensor signals, electrode combinations can be selected.

  Application Example 4 In the biological information acquisition apparatus, the plurality of electrodes of the electrode array are arranged at a central portion and an end portion of a muscle of the upper arm portion of the subject. Acquisition device.

  According to this, the detection accuracy of the electrocardiographic R wave of the electrocardiographic signal can be easily increased.

  Application Example 5 The biological information acquisition apparatus according to the above-described biological information acquisition apparatus, further including a differential amplification unit that differentially amplifies two input potentials.

  According to this, it can amplify stably by carrying out differential amplification.

The figure which showed the hardware constitutions of the electrocardiograph which concerns on 1st Embodiment. The figure which shows the structure which arrange | positions four electrodes to a biceps and a triceps in the upper arm part which concerns on 1st Embodiment. The flowchart which showed the measuring method of the electrocardiograph which concerns on 1st Embodiment. The figure which showed each waveform of the electrocardiogram measuring device which concerns on 1st Embodiment. The figure which showed the hardware constitutions of the electrocardiograph which concerns on 2nd Embodiment. The figure which showed the waveform of the acceleration with respect to the advancing direction by the arm swing at the time of the walk of the electrocardiograph which concerns on 2nd Embodiment.

(First embodiment)
FIG. 1 is a diagram illustrating a hardware configuration of an electrocardiogram measurement apparatus as a biological information acquisition apparatus according to the present embodiment.

  The electrocardiograph 2 according to the present embodiment includes an electrode array 18 including first to fourth electrodes 16 that are in contact with a human body 100 (see FIG. 2) as a subject, and two inputs of the electrode array 18. An instrumentation amplifier 20 as a differential amplifier for obtaining an electrocardiogram signal by differentially amplifying the potential of the signal, an LPF 22 for removing unnecessary high-frequency components from the signal, and an amplifier 24 for amplifying the signal to a required amplitude level And an A / D converter 26 that converts an analog signal into a digital signal, and a controller 28 that executes algorithms such as heart rate calculation, various signal processing, and arithmetic control based on the measured signal. .

  The first electrode 10 to the fourth electrode 16 are electrodes that detect a change in the potential of the human body 100 due to the activity of the heart, and are electrodes that are attached to the human body 100 when an electrocardiographic waveform is obtained. The first electrode 10 to the fourth electrode 16 are attached to the upper arm portion 102 of the human body 100. The plurality of first electrodes 10 to fourth electrode 16 of the electrode array 18 are arranged at the center (middle) and end (end) of the muscle of the upper arm 102 of the human body 100. Thereby, the detection accuracy of the electrocardiogram R wave of the electrocardiogram signal can be easily increased. The first electrode 10 to the fourth electrode 16 are each connected to two instrumentation amplifiers 20.

  The instrumentation amplifier 20 is an operational amplifier dedicated to differential amplification having a high input impedance. The instrumentation amplifier 20 is a differential amplifier circuit that amplifies the difference between two input signals of the first electrode 10 to the fourth electrode 16 by a constant coefficient (differential gain). Thereby, it can amplify stably by performing differential amplification. The gain of the instrumentation amplifier 20 is 21, for example. The instrumentation amplifier 20 is connected to the LPF 22.

  The LPF 22 is a type of filter circuit, and is a filter that passes low frequencies well and does not pass a band of frequencies higher than the Nyquist frequency. The LPF 22 is a low-pass filter having a cut-off frequency fc = 40 Hz, and eliminates aliasing at the time of sampling by removing high-frequency components of 40 Hz or more of the electrocardiogram signal supplied from the instrumentation amplifier 20 to amplify. To the unit 24. The LPF 22 is connected to the amplification unit 24.

  The amplifying unit 24 is an electronic circuit that amplifies an input electrocardiogram signal. The amplification unit 24 is connected to the A / D conversion unit 26.

  The A / D conversion unit 26 is a circuit that converts the analog signal amplified and output by the amplification unit 24 into a digital signal. The A / D converter 26 converts the electrocardiogram signal from which the high frequency component has been removed into a digital signal at a predetermined sampling frequency and supplies the digital signal to the controller 28. The A / D conversion unit 26 is connected to the control unit 28.

  The control unit 28 is a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown). When the control unit 28 executes the program stored in the ROM, the digital signal input from the A / D conversion unit 26 is analyzed and an electrocardiogram is displayed on the display unit 30 and data indicating the obtained electrocardiogram is displayed. A function of generating and storing the generated data in the storage unit 32 is realized. The controller 28 stores the acquired electrocardiogram signal, calculates the heart rate from the electrocardiogram R wave of the analyzed electrocardiogram waveform, and the like.

  In the present embodiment, the control unit 28 implements an electrocardiogram identification unit, an electrocardiogram measurement unit, a polarity detection unit, a correlation value detection unit, and an addition / subtraction process determination unit. The above-described units are realized by the control unit 28 processing a predetermined program on the electrocardiogram signal from the A / D conversion unit 26.

  The electrocardiogram identification means measures the electrocardiogram signal of the human body 100 by differentially detecting the potential between the electrodes of the electrode array 18 and identifies a plurality of electrode combinations that can take an electrocardiogram R wave from the plurality of electrodes. For example, a plurality of electrode combinations that measure R waves with the largest amplitude are specified.

  The electrocardiogram measurement means measures the electrocardiogram R wave of the electrocardiogram signal of the human body 100 by differentially detecting the potential due to the combination of the electrodes in the electrode array 18 identified by the electrocardiogram identification means.

  The polarity detection means obtains the polarity of the electrocardiogram R wave of the original electrocardiogram signal when no myoelectric noise is generated in the original electrocardiogram signal. The polarity detection means measures the electrocardiographic R wave of the electrocardiographic waveform of the human body 100 by differentially detecting all the combinations of the first electrode 10 to the fourth electrode 16 of the electrode array 18.

  The correlation value detection means obtains a correlation value of a combination of the original ECG signals when myoelectric noise is generated in the original ECG signals.

  The addition / subtraction process determining means determines the combination of the original ECG signals and the addition / subtraction process from the polarity of the electrocardiogram R wave and the correlation value. The addition / subtraction process determining means may be executed in real time. As a result, since the generation state of myoelectric noise changes due to muscle activity, the above calculation is executed in real time, and the combination of the first electrode 10 to the fourth electrode 16 is selected and the calculation of myoelectric noise removal is performed. With this, EMG noise caused by various actions can be removed.

  The display unit 30 includes a display device (for example, a liquid crystal display or an organic EL (Electro Luminescence) display) that displays an image. Under the control of the control unit 28, an electrocardiogram image or the electrocardiograph 2 is displayed. Displays screens and character strings for operations.

  The storage unit 32 has a nonvolatile memory and stores data generated by the control unit 28 under the control of the control unit 28.

  The operation unit 34 has a plurality of operation elements such as buttons for operating the electrocardiograph 2, and is connected to the control unit 28. When the operator is operated by the user, a signal indicating the operated operator is supplied to the control unit 28. The control unit 28 specifies an operation performed by the operator and an instruction from the operator based on this signal, and controls each unit.

  In the present embodiment, two different signals are transmitted to the electrocardiogram signal in the upper arm portion 102, and the magnitude of the signal differs depending on the measurement site. An electrocardiographic R wave having a stable electrocardiographic waveform can be measured by arranging the electrode array 18 so as to cover the upper arm portion 102 on the circumference and selecting an optimal electrode of the electrode array 18.

  In the upper arm portion 102, a plurality of different electrocardiographic signals are transmitted, and the polarity of the electrocardiographic R wave changes depending on the arrangement method of the electrodes 10-16. In the present embodiment, the human body 100 applies power by arranging the electrode array 18 so as to be scattered in the upper arm portion 102 and appropriately adding and subtracting signals detected by the first electrode 10 to the fourth electrode 16. Or remove myoelectric noise that occurs when moving, and can measure a stable electrocardiogram waveform.

  In the present embodiment, a signal A and a signal B having different polarities of the electrocardiographic R wave when no myoelectric noise is generated are used. The correlation between the signal A and the signal B during operation (myoelectric noise is generated) is examined. In the positive correlation where the correlation value is positive, the difference between the signal A and the signal B is taken. Since the polarity of the electrocardiogram R wave is different between the signal A and the signal B, the electrocardiogram R wave is added and strengthened by taking the difference between the signal A and the signal B. The signal A and the signal B have a positive correlation, and the myoelectric noise generated in the signal A and the signal B has the same polarity, so that the myoelectric noise is obtained by taking the difference between the signal A and the signal B. Noise is subtracted and removed.

  Alternatively, the signal A and the signal B having the same polarity of the electrocardiographic R wave when no myoelectric noise is generated are used. The correlation between the signal A and the signal B during operation (myoelectric noise is generated) is examined. In the negative correlation where the correlation value is negative, the sum of signal A and signal B is taken. Since the signal A and the signal B have the same polarity of the electrocardiogram R wave, by adding the signal A and the signal B, the electrocardiogram R wave is added and strengthened. The signal A and the signal B have a negative correlation, and the myoelectric noise generated in the signal A and the signal B has different polarities. Therefore, by taking the sum of the signal A and the signal B, the myoelectric noise Are subtracted and removed.

  FIG. 2 is a diagram illustrating a configuration in which the four first electrodes 10 to the fourth electrode 16 are arranged on the biceps 104 and the triceps 106 in the upper arm 102 according to the present embodiment. In the upper arm portion 102, four first to fourth electrodes 16 are arranged on the biceps 104 and the triceps 106, and a signal is detected by a combination of electrodes as indicated by arrows in FIG. In this combination, the polarity of the electrocardiogram R wave is as follows. The polarity of the electrocardiographic R wave between the first electrode 10 and the fourth electrode 16 is positive. The polarity of the electrocardiographic R wave between the second electrode 12 and the third electrode 14 is negative. The polarity of the electrocardiographic R wave between the first electrode 10 and the third electrode 14 is negative. The polarity of the electrocardiographic R wave between the second electrode 12 and the fourth electrode 16 is positive. The polarity of the electrocardiographic R wave between the first electrode 10 and the second electrode 12 is positive.

  On the other hand, myoelectric noise shows a property different from that of the electrocardiographic R wave. For example, when the myoelectric noise in the raised hand state is detected, signals between the first electrode 10 and the fourth electrode 16 and between the second electrode 12 and the third electrode 14 have the same polarity (correlation value). It becomes. This is thought to be due to the fact that two different signals are transmitted to the electrocardiogram signal in the upper arm 102 and that the myoelectric noise signal generates more potential where there are many muscle fibers.

  More specifically, the first electrode 10 and the second electrode 12 are arranged in the middle of the bicep in the middle of the upper arm 102, and the third electrode 14 and the fourth electrode 16 are respectively composed of the biceps 104 and the three It is arranged at the end of the head muscle 106. Since the position of the first electrode 10 and the second electrode 12 has a larger potential generated by muscle activity than the position of the third electrode 14 and the fourth electrode 16, the first electrode 10 and the fourth electrode 16 And between the second electrode 12 and the third electrode 14 have the same polarity (correlation value). On the other hand, different electrocardiographic signals are transmitted between the biceps 104 and the triceps 106 and between the first electrode 10 and the fourth electrode 16 and between the second electrode 12 and the third electrode 14. The polarity of ECG R wave peaks is always opposite.

  It should be noted that the muscle activity differs depending on the operation, and it is not preferable to fix the combination of the first electrode 10 to the fourth electrode 16 to be detected, and it is determined whether the detected plurality of signals detect the same myoelectric noise signal. However, it may be changed in real time (performed by correlation calculation). That is, the addition / subtraction process determining means may be executed in real time.

  In this embodiment, paying attention to the above features, a signal is detected using a plurality of first electrode 10 to fourth electrode 16, and the polarity of the detected electrocardiogram R wave and the signal when myoelectric noise is generated are detected. Then, the subsequent signal processing is determined from the correlation value.

(Correlation value calculation formula)
Assume that n sets of data variables x and y are as shown in Equation (1).

The correlation value is expressed by the following formula.

For example, x ₁ to x _{n in the} equation (2) are time series data of the electrocardiogram signal measured by the electrode combination A, and y _{1 to} y _n are time series data of the electrocardiogram signal measured by the electrode combination B.

Specifically, the following steps are performed.
FIG. 3 is a flowchart showing a measurement method of the electrocardiograph 2 according to the present embodiment. First, in step S10, electrocardiogram measurement is performed on the first electrode 10 to the fourth electrode 16 arranged in a predetermined combination, and the electrocardiogram R in each combination of the first electrode 10 to the fourth electrode 16 at rest. Detect the polarity of the wave.

  Next, in step S20, electrocardiogram measurement is performed from any combination of the first electrode 10 to the fourth electrode 16.

  Next, in step S30, it is determined whether the signal is stationary at the RMS (root mean square) level of the signal. An electrocardiogram R wave is detected from any combination of the first electrode 10 to the fourth electrode 16 without calculation during rest (step S60). Thereafter, the process returns to step S20 to perform electrocardiogram measurement. During operation, the process proceeds to step S40. Specifically, since the myoelectric noise that is not mixed at the time of operation is included in each detection signal during operation, the amplitude RMS value of the signal is increased. The determination of whether or not the vehicle is stationary may be an average of absolute values. It may also be a point in time when a clear electrocardiographic R wave cannot be detected.

  Next, when the myoelectric noise is detected in step S40, the correlation value of the signal obtained by the combination of the first electrode 10 to the fourth electrode 16 is calculated.

  Next, in step S50, the polarity of the electrocardiogram R wave in the combination of each of the first electrode 10 to the fourth electrode 16 and the correlation value are selected so that the polarity of the electrocardiogram R wave is opposite and the correlation value is positive. By subtracting the two detection signals, the electrocardiogram R wave is added and becomes larger, and the myoelectric noise is subtracted and removed. Or, the same is true for the ECG R wave having the same polarity and a negative correlation value. By adding two signals, the ECG R wave is added and becomes larger, and the myoelectric noise is subtracted and removed. . Note that specific numerical values of the correlation value at the time of selection may be, for example, positive: 0.6 or more and negative: −0.6 or less.

  Next, in step S60, an electrocardiographic R wave is detected from the combination of the first electrode 10 to the fourth electrode 16 from which myoelectric noise has been removed.

  Thereafter, when the detection of motion or the detection of myoelectric noise continues, the processing of step S40 to step S50 is repeated, and the optimum combination and calculation of the first electrode 10 to the fourth electrode 16 are performed even when the motion is changed. Can be determined.

  In the above processing, it is not necessary to use all combinations of the first electrode 10 to the fourth electrode 16 for addition and subtraction, and it can be determined whether or not the combination can be used for calculation from the correlation value of myoelectric noise. If the correlation is low (correlation value is close to 0), it can be determined that the same myoelectric noise is not present, so that it can be excluded from addition and subtraction.

  In this embodiment, the object of addition / subtraction is the one having the highest correlation, but the correlation may be second or later. The target of addition / subtraction may be a set of signals or an addition value of a plurality of sets of signals. Furthermore, the number of electrode combinations may be one or more.

  FIG. 4 is a diagram showing each waveform of the electrocardiograph 2 according to the present embodiment. 4A shows a signal A35 between the first electrode 10 and the fourth electrode 16 in FIG. The signal A35 includes noise as a random signal. FIG. 4B shows a signal B 36 between the second electrode 12 and the third electrode 14. The signal B36 has a noise as a random signal. FIG. 4C is a waveform 37 showing the result of the correlation value detection means between the signal A35 and the signal B36. It can be seen from the waveform 37 that the signal A35 and the signal B36 show a positive correlation. FIG. 4D shows a waveform 38 of a signal obtained by subtracting the signal B36 from the signal A35 by the addition / subtraction process determining means. The waveform 38 periodically has a peak. FIG. 4E shows an electrocardiographic signal 40 measured to know the timing of the peak of the electrocardiographic R wave. Compared with the peak of the electrocardiogram signal 40, the peak of the waveform 38 is generated when the peak occurs (indicated by an arrow 108).

  The signals A35 and B36 alone are buried in myoelectric noise and the electrocardiographic R wave cannot be discriminated. On the other hand, when the processing is performed according to the above-described steps, the signals A35 and B36 are stationary when the electrocardiogram R wave has positive and negative polarities, and the correlation calculation of the signal in which myoelectric noise is generated. The results of have a positive correlation.

  There is a variable n in the above formula (2), and it is necessary to set in which interval the correlation value is calculated. In FIG. 4C, a correlation value is calculated in a section of 0.25 seconds, and it can be seen that there is a positive correlation (distributed on the +1 side). The variable n can be set arbitrarily. However, if n is reduced, the calculation period becomes shorter. Therefore, the frequency of changing the electrode combination can be increased, and the followability of the operation is improved. On the other hand, there is a demerit that the correlation value varies due to influences other than myoelectric noise.

  Therefore, the calculation of signal A35-signal B36 is performed. As a result, the myoelectric noise is removed, and the S / N is improved so that the peak of the electrocardiographic R wave can be discriminated as shown in FIG.

  In the above description, the case where the first electrode 10 to the fourth electrode 16 are four has been described. However, the number of electrodes may be three, and even if one electrode is used in common, the effect can be obtained (by muscle activity). It is also possible to use four or more electrodes, and the addition / subtraction can be determined from the correlation value between the polarity of the electrocardiogram R wave between each electrode and the myoelectric noise, and the myoelectric noise can be removed. The electrode positions shown in FIG. 2 are an example.

  According to the present embodiment, an electrocardiogram signal measured from the plurality of first electrodes 10 to the fourth electrode 16 is determined by determining the calculation method from the correlation value between the polarity of the electrocardiogram R wave and the signal on which the noise is placed. The combination of electrodes that can remove myoelectric noise can be selected, and an electrocardiographic signal with little myoelectric noise can be obtained. In other words, regarding the detection of the electrocardiogram signal, stable signal detection is performed by adding the electrocardiogram signals measured from the plurality of first electrodes 10 to the fourth electrode 16 so that the amplitude of the electrocardiogram R wave is maximized. It can be carried out.

  Specifically, the detection signal at A and B during operation is different from the combination of electrodes A and B of the positive and negative signals of the electrocardiographic R wave when no myoelectric noise is generated. If the correlation is positive, by calculating AB, the electrocardiogram R wave is added and the myoelectric noise is removed (the ECG R wave has the same sign and the correlation between the detection signals A and B is May be negative).

(Second Embodiment)
FIG. 5 is a diagram illustrating a hardware configuration of the electrocardiogram measurement apparatus according to the present embodiment. In FIG. 5, the same reference numerals are given to the same components as the components according to the first embodiment, and description thereof will be omitted as appropriate.

  The electrocardiograph 4 according to the present embodiment is attached to at least a part of the human body 100 as a subject, and the human body 100 moves by detecting a mechanical quantity using a vibrator that vibrates based on a drive signal. An acceleration sensor 42 serving as a mechanical quantity detection unit used for determining whether the medium is in the middle, an amplification unit 44 that amplifies the signal of the acceleration sensor 42 to a required amplitude level, and an A / D conversion that converts an analog signal into a digital signal And a motion analysis unit 43 as a motion analysis unit for analyzing a signal from the acceleration sensor 42.

  The acceleration sensor 42 is arranged so that the direction in which the arm is shaken, the direction in which acceleration is applied, and the longitudinal direction of the crystal tube are perpendicular to each other. The acceleration sensor 42 may be attached to a part of the human body 100 such as an arm or a waist. Note that the mechanical quantity detection device that detects the mechanical quantity using the vibrator may be an angular velocity sensor (gyro sensor).

  The amplification unit 44 is an electronic circuit that amplifies the input electrocardiogram signal. The amplification unit 44 is connected to the A / D conversion unit 46.

  The A / D conversion unit 46 is a circuit that converts the analog signal amplified and output by the amplification unit 44 into a digital signal. The A / D converter 46 converts the electrocardiogram signal from which the high-frequency component has been removed into a digital signal at a predetermined sampling frequency and supplies the digital signal to the controller 28. The A / D conversion unit 46 is connected to the control unit 28.

  In the present embodiment, the control unit 28 implements an operation analysis unit 43. The motion analysis unit 43 is realized by the control unit 28 processing the electrocardiogram signal from the A / D conversion unit 46 with a predetermined program. For each movement of the human body 100, the motion analysis unit 43 generates a file in which a combination of the first electrode 10 to the fourth electrode 16 used at that time and a calculation method are made into a database, and acceleration is generated using the generated file. Based on the signal from the sensor 42, the combination of the first electrode 10 to the fourth electrode 16 is selected.

  Compared to FIG. 1, an acceleration sensor 42 is added. The control unit 28 includes a motion analysis unit 43 that estimates how the human body 100 is moving based on a signal from the acceleration sensor 42, and the motion estimated by the motion analysis unit 43 and the acceleration sensor 42. The signal, the combination of the first electrode 10 to the fourth electrode 16 determined by the same method as in the first embodiment, and the calculation are recorded. The control unit 28 builds a database of combinations of the first electrode 10 to the fourth electrode 16 determined at that time on the operation of the human body 100 on a RAM (not shown). Changes the combination of the first electrode 10 to the fourth electrode 16 according to the output signal of the acceleration sensor 42.

  In the present embodiment, the acceleration sensor 42 is attached to the human body 100, the movement of the human body 100 is estimated, the combination of the predicted movement, the first electrode 10 to the fourth electrode 16 used at that time, the calculation method, and the database are recorded. Turn into. When the database is accumulated, the motion is estimated by the acceleration sensor 42, and the combination of the first electrode 10 to the fourth electrode 16 is selected. For example, in walking and running, the movement of the upper arm is monotonous, and myoelectric noise is generated in accordance with the movement. Therefore, after the data is accumulated, the combination of the first electrode 10 to the fourth electrode 16 can be selected from the database and the signal from the acceleration sensor 42 without performing the processing of the first embodiment each time.

  FIG. 6 is a diagram showing a waveform of acceleration with respect to the traveling direction by arm swinging during walking of the electrocardiograph 4 according to the present embodiment. Note that the front vertex in the figure is a point where the direction of arm swing is switched from front to rear, and the acceleration of arm swing is zero. The rear vertex is the point where the direction of arm swing switches from the rear to the front, and the acceleration of arm swing becomes zero. The straight side is the point where the arm passes the side of the body, and the absolute value of the acceleration of the arm swing is maximized.

  If the combination of the first electrode 10 to the fourth electrode 16 according to the method of the first embodiment is changed in two sections (combination 1 and 2) in one cycle of walking arm swing, the database contains The motion (walking), the waveform pattern of the acceleration data, the combination of the first electrode 10 to the fourth electrode 16 and the calculation method are recorded. Thereafter, when the motion analysis unit 43 of the control unit 28 determines that the human body 100 is walking, the combination of the first electrode 10 to the fourth electrode 16 according to the waveform pattern of the acceleration data and the calculation method, Is used.

  Thereby, the acceleration sensor 42 is attached, the motion of the human body 100 is estimated, the predicted motion, the combination of the first electrode 10 to the fourth electrode 16 used at that time, and the calculation method are recorded and databased. When the database is accumulated, a combination of the first electrode 10 to the fourth electrode 16 is selected based on a signal from the acceleration sensor 42. For example, during walking and running, the movement of the upper arm 102 is monotonous, and myoelectric noise is generated in accordance with the movement. A combination of the first electrode 10 to the fourth electrode 16 can be selected from the database and the signal of the acceleration sensor 42.

  In the first embodiment, signals are detected for the combination of the plurality of first electrodes 10 to the fourth electrode 16, but the actual operation is performed by performing the operation analysis by the operation analysis unit 43 of the control unit 28. The combination of the first electrode 10 to the fourth electrode 16 can be reduced, and the power consumption can be reduced.

  If the signal from the acceleration sensor 42 cannot be matched with the past operation or if the electrocardiogram R wave cannot be detected continuously, it is possible to return to the operation as in the first embodiment as the normal mode. is there. Further, in order to accurately control the operation analysis unit 43 of the control unit 28, the human body 100 may be set to the type of exercise such as walking, running, and exercise bike.

  In this embodiment, the electrocardiographs 2 and 4 are attached to the upper arm 102, but measurement may be performed by attaching them to the thigh of the human body 100.

  DESCRIPTION OF SYMBOLS 2, 4 ... Electrocardiograph (biological information acquisition apparatus) 10 ... 1st electrode (electrode) 12 ... 2nd electrode (electrode) 14 ... 3rd electrode (electrode) 16 ... 4th electrode (electrode) 18 ... Electrode array DESCRIPTION OF SYMBOLS 20 ... Instrumentation amplifier (differential amplification part) 22 ... LPF 24 ... Amplification part 26 ... A / D conversion part 28 ... Control part 30 ... Display part 32 ... Memory | storage part 34 ... Operation part 35 ... Signal A 36 ... Signal B 37 , 38 ... Waveform 40 ... Electrocardiogram signal 42 ... Accelerometer 43 ... Motion analysis unit (motion analysis means) 44 ... Amplification unit 46 ... A / D conversion unit 100 ... Human body (subject) 102 ... Upper arm 104 ... Biceps 106 ... triceps 108 ... arrow.

Claims (5)

An electrode array comprising a plurality of electrodes in contact with the subject;
A heart that measures the electrocardiographic R wave of the electrocardiographic signal of the subject by differentially detecting the potential between the electrodes of the electrode array, and identifies a plurality of electrode combinations that can take the electrocardiographic R wave from the plurality of electrodes. Electric identification means;
An electrocardiogram measurement unit that measures an electrocardiogram R wave of the electrocardiogram signal of the subject by differentially detecting a potential due to a combination of electrodes in the electrode array identified by the electrocardiogram identification unit;
Polarity detection means for determining the polarity of the electrocardiogram R wave when there is no myoelectric noise of the electrocardiogram signal based on the measurement result of the electrocardiogram R wave by the electrocardiogram measurement means;
Correlation value detection for obtaining a correlation value of the electrocardiogram signal by a combination of electrodes in the electrode array when there is myoelectric noise of the electrocardiogram signal based on a measurement result of the electrocardiogram R wave by the electrocardiogram measurement means Means,
An addition / subtraction process determination means for determining a combination of the electrocardiogram signals and an addition / subtraction process from the polarity of the electrocardiogram R wave obtained by the polarity detection means and the correlation value obtained by the correlation value detection means;
A biometric information acquisition apparatus comprising: The biological information acquisition apparatus according to claim 1,
The biological information acquisition apparatus according to claim 1, wherein the addition / subtraction process determination means is executed in real time. The biological information acquisition apparatus according to claim 1 or 2,
A mechanical quantity detector that is attached to at least a part of the body of the subject and detects a mechanical quantity by a vibrator that vibrates based on a drive signal, and is used to determine whether or not the subject is in motion; ,
Motion analysis means for analyzing a signal from the mechanical quantity detection unit;
Including
The motion analysis unit generates a file in which the combination of the electrodes used at that time and the calculation method are made into a database for each movement of the subject, and from the mechanical quantity detection unit using the generated file. A biological information acquisition apparatus that selects a combination of the electrodes based on the signal. In the biometric information acquisition device according to any one of claims 1 to 3,
The biological information acquisition apparatus according to claim 1, wherein the plurality of electrodes of the electrode array are arranged at a central portion and an end portion of a muscle of the upper arm portion of the subject. In the living body information acquisition device according to any one of claims 1 to 4,
A biological information acquisition apparatus, further comprising a differential amplifier that differentially amplifies the potentials of two inputs.