JP2013013486A - Biological information processing device and biological information processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new method for determining appropriateness of a calculated pulse rate.SOLUTION: In a pulse rate monitor 1, a pulse rate calculation part 120 calculates the pulse rate of a test subject. A pulse rate appropriateness determination part 160 determines appropriateness of the calculated pulse rate, based on whether the calculated pulse rate calculated by the pulse rate calculation part 120 is included in a given window or not. A window width setting part 140 sets a window width being the width of a window, based on the value of the consecutive times of negative determination (inappropriateness determination) by the pulse rate appropriateness determination part 160.

Description

  The present invention relates to a biological information processing apparatus and a biological information processing method.

  2. Description of the Related Art Conventionally, as a biological information processing apparatus used for exercise management and health management of a subject, a pulsometer that is attached to a part of the subject's body and measures the subject's pulse rate is known. The pulse meter detects a change in blood flow of the subject wearing the device, calculates the pulse rate of the subject, and calculates the calculated pulse rate (hereinafter referred to as “calculated pulse rate”) as a measurement result. This is to notify the subject. As a pulsometer, one using light, one using ultrasonic waves, one using electrocardiogram, and the like are known.

  Whether or not the pulse rate can be calculated correctly depends largely on the accuracy with which changes in the blood flow of the subject are detected. However, the accuracy of detecting a change in blood flow may be reduced due to an influence of disturbance such as a change in outside air temperature, a physical effect such as a position of the pulse meter and a shift in the position of attachment. In view of this, a technique has been devised in which an allowable range of variation for the calculated pulse rate is set to determine the suitability of the calculated pulse rate (for example, Patent Document 1 and Patent Document 2).

JP-A-9-113309 JP-A-9-154825

  However, there are various problems in how to set the fluctuation allowable range. For example, when the setting of the fluctuation allowable range itself is incorrect, even if the calculated pulse rate is a normal value, it is determined to be inappropriate. Therefore, in Patent Document 1, when the calculated pulse rate deviates continuously from the fluctuation allowable range in the same direction (in the direction exceeding the upper limit or in the direction lower than the lower limit) for a predetermined threshold number of times (for example, 3 times). Describes a method for determining the calculated pulse rate as appropriate. However, with this method, even if the calculated pulse rate is clearly an abnormal value, there is a risk of erroneous determination as appropriate.

  However, in order to avoid misjudgment, if the above threshold number is increased excessively, it takes a long time to determine that the calculated pulse rate, which is a normal value, is appropriate. ) Decreases.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to propose a new method for determining the suitability of a calculated pulse rate.

  A first form for solving the above problems includes a pulse rate calculation unit that calculates a pulse rate of a subject, and a calculated pulse rate calculated by the pulse rate calculation unit is included in a given fluctuation allowable range. The pulse rate appropriateness determination unit that determines the appropriateness of the calculated pulse rate based on whether or not the pulse rate is appropriate, and the variation based on any one of the number of consecutive negative determinations by the pulse rate appropriateness determination unit, the duration, and the frequency The biological information processing apparatus includes a fluctuation allowable width setting unit that sets a fluctuation allowable width that is a width of an allowable range.

  As another form, the suitability of the calculated pulse rate is determined based on calculating the pulse rate of the subject and whether the calculated calculated pulse rate is included in a given allowable fluctuation range. A biological information processing method including: setting a variation allowable range that is a width of the variation allowable range based on any one of the number of consecutive negative determinations by the suitability determination, the duration, and the frequency. It may be configured.

  According to the first form and the like, the pulse rate of the subject is calculated by the pulse rate calculation unit. Then, based on whether or not the calculated pulse rate calculated by the pulse rate calculation unit is included in the given allowable fluctuation range, the suitability of the calculated pulse rate is determined by the pulse rate suitability determination unit. When the calculated pulse rate is not included in the allowable fluctuation range, it is determined that the calculated pulse rate is inappropriate. Then, the fluctuation allowable width that is the width of the fluctuation allowable range is set by the fluctuation allowable width setting unit based on any one of the values of the negative determination continuous count, duration, and frequency by the pulse rate suitability determination unit.

  Rather than making the allowable fluctuation range fixed, the variable allowable range is optimized by variably setting the negative pulse based on the appropriateness of the calculated pulse rate based on the number of consecutive times, duration, and frequency. can do. Then, by using the fluctuation allowable range having the set allowable fluctuation range, it is possible to correctly determine the suitability of the calculated pulse rate.

  Further, as a second mode, in the biological information processing apparatus according to the first mode, the variation allowable range setting unit sets the variation allowable range so that the variation allowable range increases as the value increases. An information processing apparatus may be configured.

  According to the second embodiment, the fluctuation allowable range is increased as the value of any of the number of consecutive negative determinations based on the appropriateness determination of the calculated pulse rate, the duration time, and the frequency increases, so that the pulse rate of the subject can be increased. It is possible to make the variation allowable range follow the change.

  In this case, for example, as the third mode, the variation allowable width setting unit in the biological information processing device of the second mode is configured to linearly increase the variation allowable range with respect to the value. It is good to do.

  According to the third embodiment, the pulse rate of the subject has changed abruptly by linearly increasing the fluctuation tolerance with respect to any of the values of the continuous negative determination, duration, and frequency. Even in this case, the calculated pulse rate can be determined as appropriate, and the changing pulse rate can be accurately captured.

  For example, as a fourth form, the biometric information processing apparatus in which the variation allowable width setting unit in the biometric information processing apparatus of the second aspect reduces the increase degree of the variation allowable width as the value increases. It is good as well.

  According to the fourth embodiment, the variation allowable range is prevented from becoming excessively wide by decreasing the increase degree of the variation allowable range as the value of any of the negative determination continuous count, duration, and frequency increases. In addition, the possibility of capturing abnormal values can be reduced. Even if the pulse rate of the subject changes suddenly, the change in the pulse rate tends to be moderate thereafter. Therefore, it is possible to determine the suitability of the calculated pulse rate by setting a permissible fluctuation range that matches the actual change rate of the human pulse rate.

  Further, as a fifth mode, in the biological information processing apparatus according to any one of the first to fourth modes, the pulse rate calculation unit further includes a reliability determination unit that determines the reliability of the calculation result of the pulse rate calculation unit, and the pulse rate The suitability determination unit may configure a biological information processing apparatus that determines the suitability of the calculated pulse rate using the variation allowable range and the reliability.

  According to the fifth aspect, the reliability of the calculation result of the pulse rate calculation unit is determined by the reliability determination unit. By using the reliability of the calculation result of the pulse rate in addition to the fluctuation allowable range, it is possible to improve the accuracy of determining the suitability of the calculated pulse rate.

  As a sixth aspect, in the biological information processing apparatus according to the fifth aspect, the reliability determination unit determines the reliability based on a signal-to-noise ratio of a signal in which the pulse wave of the subject is detected. The pulse rate suitability determining unit determines that the calculated pulse rate is appropriate when the signal-to-noise ratio satisfies a predetermined threshold condition and the calculated pulse rate is included in the fluctuation allowable range. An information processing apparatus may be configured.

  It is estimated that the reliability of the pulse rate calculation result is higher as the signal-to-noise ratio of the signal in which the pulse wave of the subject is detected is better. Therefore, according to the sixth embodiment, when the signal-to-noise ratio of the signal in which the pulse wave of the subject is detected satisfies a predetermined threshold condition and the calculated pulse rate is included in the fluctuation allowable range, the calculated pulse rate Determine the number as appropriate.

  As a seventh aspect, in the biological information processing apparatus according to any one of the first to sixth aspects, the allowable fluctuation range is a range determined based on a given reference pulse rate, and whether the pulse rate is appropriate When the determination unit determines that the calculated pulse rate is appropriate, the biological information processing apparatus may further include a reference pulse rate updating unit that updates the reference pulse rate with the calculated pulse rate.

  According to the seventh aspect, when the calculated pulse rate is determined to be appropriate by the pulse rate suitability determining unit, the reference pulse rate that is used as a reference for the allowable fluctuation range is updated by the reference pulse rate updating unit. Is done. As a result, it is possible to optimize the standard of the allowable fluctuation range, set an appropriate allowable fluctuation range each time, and determine whether the calculated pulse rate is appropriate.

The front view of a pulse meter. (A) Rear view of pulse meter. (B) The use state figure of a pulse meter. Explanatory drawing of operation | movement of a pulse wave sensor. Explanatory drawing of the suitability determination method of a calculated pulse rate. Explanatory drawing of the 1st setting method of window width. Explanatory drawing of the 2nd setting method of window width. The block diagram which shows the function structure of a pulse meter. The flowchart which shows the flow of a pulse rate measurement process. The flowchart which shows the flow of a 2nd pulse rate measurement process.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. This embodiment is an embodiment in which the biological information processing apparatus of the present invention is applied to a wristwatch-type pulse meter. Needless to say, embodiments to which the present invention is applicable are not limited to the embodiments described below.

1. External Configuration FIG. 1 is a front view of a pulse meter 1 in the present embodiment. The pulsometer 1 includes a wristband 2, and the case 3, the time, the operating state of the pulsometer 1, and various biological information (pulse rate, exercise intensity, calorie consumption, etc.) are displayed by letters, numbers, icons, etc. A liquid crystal display 4 for this purpose is arranged.

  An operation button 5 for operating the pulsometer 1 is disposed on the peripheral portion (side surface) of the case 3. The pulse meter 1 operates using, for example, a built-in secondary battery as a power source. A charging terminal 6 for charging the built-in secondary battery is disposed on the side surface of the case 3 so as to be connected to an external charger.

  FIG. 2A is a rear view of the pulse meter 1 and shows an external view when the pulse meter 1 is viewed from the rear surface of the case 3. Moreover, FIG. 2 (B) is a use state diagram of the pulsometer 1 and shows a side view of the pulsometer 1 in a state of being worn on the wrist WR of the subject.

  A pulse wave sensor 10 that detects a pulse wave of the subject and outputs a pulse wave signal is disposed on the back surface of the case 3. The pulse wave sensor 10 detects a pulse wave at the wrist WR of the subject in contact with the back surface of the case 3. In the present embodiment, the pulse wave sensor 10 is a photoelectric pulse wave sensor and includes a mechanism for optically detecting the pulse wave.

  FIG. 3 is an enlarged view when the internal structure of the pulse wave sensor 10 is viewed from the side surface of the case 3. The pulse wave sensor 10 is installed in a hemispherical storage space having a circular bottom surface formed on the back side of the case 3. A light source 12 such as an LED (Light Emitting Diode) and a light receiving element 13 such as a phototransistor are built in the storage space. The inner surface of the hemisphere is a reflecting surface 11 that is a mirror surface, and the light receiving element 13 and the light source 12 are mounted on the upper surface and the lower surface of the substrate 14, respectively, when the bottom surface side of the hemisphere is downward.

  When the light Le is irradiated by the light source 12 toward the skin SK of the user's wrist WR, the irradiated light Le is reflected by the subcutaneous blood vessel BV and returns to the hemisphere as reflected light Lr. The reflected light Lr is further reflected by the hemispherical reflecting surface 11 and enters the light receiving element 13 from above.

  The intensity of the reflected light Lr from the blood vessel BV changes due to the absorption action of hemoglobin in the blood, reflecting the change in blood flow. The pulse wave sensor 10 blinks the light source 12 at a predetermined cycle at a cycle earlier than the pulsation. The light receiving element 13 outputs a pulse wave signal corresponding to the received light intensity by photoelectric conversion for each lighting opportunity of the light source 12. The pulse wave sensor 10 blinks the light source 12 at a frequency of, for example, 128 Hz.

  As shown in FIG. 2A, the pulsometer 1 includes a body motion sensor 20 for detecting the body motion of the subject. In the present embodiment, the body motion sensor 20 includes an acceleration sensor. As shown in FIG. 1, the acceleration sensor has, for example, the normal direction of the cover glass surface of the case 3 and the Z axis with the display surface side positive, and the vertical direction with the 12 o'clock direction of the watch as positive is the Y axis. This is a triaxial acceleration sensor having the X axis as the left-right direction with the 3 o'clock direction of the watch as positive.

  In a state where the pulsometer 1 is worn, the X axis coincides with the direction from the subject's elbow to the wrist. The body motion sensor 20 detects acceleration in three axes of the X axis, the Y axis, and the Z axis, and outputs the result as a body motion signal. The pulsometer 1 detects a periodic body movement (for example, an arm movement or a vertical movement of the body) of the subject accompanying walking or jogging based on the body movement signal detected by the body movement sensor 20. .

2. Principle The pulsometer 1 calculates the pulse rate of the subject using the pulse wave signal detected by the pulse wave sensor 10. Specifically, a predetermined frequency decomposition process is performed on the pulse wave signal, and a signal intensity value (spectrum value) for each frequency band is extracted. The frequency decomposition process can be a process to which, for example, a fast Fourier transform (FFT) is applied. Then, a frequency spectrum corresponding to the pulse wave of the subject is specified from the extracted signal intensity value, and the pulse rate is calculated based on the frequency (or period). The pulsometer 1 calculates the pulse rate at a predetermined time interval (for example, every 1 to 5 seconds). In the present embodiment, the pulse rate of the subject calculated as described above is referred to as “calculated pulse rate”.

  The pulse meter 1 notifies the subject by displaying the calculated pulse rate on the liquid crystal display 4 as the pulse rate of the measurement result (measured pulse rate). However, for example, a calculation greatly deviating from the actual pulse rate of the subject due to the influence of disturbance such as a change in the outside air temperature or the physical influence such as the wearing position of the pulse meter 1 and the deviation of the wearing position. The pulse rate may be obtained as a measurement result. The calculated pulse rate obtained in this case is an abnormal value, and it is not appropriate to notify the subject of the value. Therefore, in this embodiment, the suitability of the calculated pulse rate is determined according to the procedure described below.

  In this embodiment, a range having the same width in the height direction with respect to a given reference pulse rate is defined as a window. The reference pulse rate is a reference value of the pulse rate at the calculation time (calculation timing) of the pulse rate. In the present embodiment, the latest calculated pulse rate determined to be appropriate by the suitability determination is set as the reference pulse rate. Specifically, when it is determined that the calculated pulse rate is appropriate, the process of updating the reference pulse rate with the calculated pulse rate is repeated for each calculated time.

  For each calculation time, it is determined whether the calculated pulse rate is included in the window. When the calculated pulse rate is included in the window, the calculated pulse rate is determined to be appropriate. On the other hand, when the calculated pulse rate is not included in the window, the calculated pulse rate is determined to be inappropriate. The window is a range that allows fluctuations in the calculated pulse rate that is calculated based on a given reference pulse rate (hereinafter referred to as “fluctuation allowable range”).

  In the present embodiment, the number of consecutive times that the calculated pulse rate is determined to be inappropriate by the above-described determination of the appropriateness of the pulse rate (hereinafter referred to as “the inappropriate number of inappropriate determination times”) is counted, and the reference value increases as the value increases. Increase window width for pulse rate.

In the following description, the window width is expressed as “W”. The number of consecutive inappropriate determinations is expressed as “N”, and the window width “W = W ₀ ” when “N = 0” is referred to as “initial window width”. Further, the calculation time of the pulse rate is expressed as “t”.

  FIG. 4 is an explanatory diagram of a method for determining the suitability of the calculated pulse rate in the present embodiment. In FIG. 4, the horizontal axis is the time axis, and the discrete calculation time “t” is shown below the time axis. The vertical axis is the pulse rate. The calculated pulse rate is indicated by a triangular plot, and the reference pulse rate is indicated by a rectangular plot.

Starting from a state where the reference pulse rate at the calculation time “t1” is “HR ₀ ” and the window width is the initial window width “W ₀ ”. That is, the window at the calculation time “t1” is set as an allowable variation range in which the center is the reference pulse rate “HR ₀ ” and the width is the initial window width “W ₀ ”. In FIG. 4, the calculated pulse rate at the calculation time “t1” is “HR ₁ (<HR ₀ )”, and the value is included in the window. For this reason, it is determined that the calculated pulse rate “HR ₁ ” is appropriate. The number of consecutive inappropriate determinations “N” remains “0” and is not updated. Further, the reference pulse rate is updated with the calculated pulse rate “HR ₁ ”.

At the calculation time “t2”, a window based on the calculated pulse rate “HR ₁ ” is set. Since “N = 0”, a window is set whose center is the reference pulse rate “HR ₁ ” and whose width is the initial window width “W ₀ ”. In FIG. 4, the calculated pulse rate at the calculated time “t2” is “HR ₂ (<HR ₁ )” and is included in the window. For this reason, it is determined that the calculated pulse rate “HR ₂ ” is appropriate. The number of consecutive inappropriate determinations “N” remains “0” and is not updated. Further, the reference pulse rate is updated with the calculated pulse rate “HR ₂ ”.

At the calculation time “t3”, a window based on the calculated pulse rate “HR ₂ ” is set. Since “N = 0”, a window is set whose center is the reference pulse rate “HR ₂ ” and whose width is the initial window width “W ₀ ”. In FIG. 4, “HR ₃ (<HR ₂ )” greatly deviating from the actual pulse rate of the subject is obtained as the calculated pulse rate at the calculation time “t3”. In this case, since the calculated pulse rate “HR ₃ ” is not included in the window, it is determined to be inappropriate. In addition, since it is determined as inappropriate, the number of consecutive inappropriate determinations “N” is updated to “1”. The reference pulse rate remains “HR ₂ ” and is not updated.

At the calculation time “t4”, a window based on the calculated pulse rate “HR ₂ ” is set. Since “N = 1”, not the initial window width “W ₀ ” but a wider window width “W ₁ (> W ₀ )” is set. In FIG. 4, since the calculated pulse rate “HR ₄ (> HR ₃ )” at the calculation time “t4” is included in the window, the calculated pulse rate “HR ₄ ” is determined to be appropriate. Further, since it is determined to be appropriate, the number of consecutive inappropriate determinations “N” is reset to “0”. Further, the reference pulse rate is updated with the calculated pulse rate “HR ₄ ”.

Thereafter, the suitability of the calculated pulse rate is determined in the same procedure. FIG. 4 shows a case where the pulse rate of the subject suddenly increases from “HR ₆ ” to “HR ₇ ” at the calculation time “t7”. In this case, at the calculation time “t7”, the window cannot follow the rapid rise in the pulse rate, and the calculated pulse rate “HR ₇ ” is out of the window. Therefore, the calculated pulse rate “HR ₇ ” is determined to be inappropriate, and the inappropriate determination continuous number of times “N” is updated to “1”.

Since “N = 1”, at the next calculation time “t8”, a window whose center is the reference pulse rate “HR ₆ ” and whose width is the window width “W ₁ (> W ₀ )” is set. At this time, “HR ₈ (> HR ₇ )” is obtained as the calculated pulse rate at the calculated time “t8”. However, although the window is widened, the calculated pulse rate “HR ₈ ” cannot be captured. In this case, the calculated pulse rate “HR ₈ ” is determined to be inappropriate, and the inappropriate determination continuous number of times “N” is updated to “2”.

Since “N = 2”, at the next calculation time “t9”, a window whose center is the reference pulse rate “HR ₆ ” and whose width is the window width “W ₂ (> W ₁ )” is set. That is, a window wider than the window set at the calculation time “t8” is set. In FIG. 4, at the calculation time “t9”, “HR ₉ (> HR ₈ )” is obtained as the calculated pulse rate. As a result of expanding the window, the calculated pulse rate “HR ₉ ” is determined to be appropriate. Accordingly, the number of consecutive inappropriate determinations “N” is reset to “0”.

  Thus, in this embodiment, one of the features is that the window width is increased as the value of the number of consecutive inappropriate determinations increases. Even when a value that deviates greatly from the true pulse rate is obtained as the calculated pulse time “t3”, since the window is initially set to be narrow, an abnormal value is erroneously set to be appropriate. Judgment is prevented. Even if the subject's pulse rate suddenly changes, the window is expanded every time the calculated pulse rate is determined to be inappropriate, so it is possible to determine that the calculated pulse rate is appropriate at an early stage. It becomes possible. In other words, it can be said that an appropriate calculated pulse rate can be captured at an early stage.

  FIG. 5 is an explanatory diagram of a first setting method of the window width. In FIG. 5, the horizontal axis is the pulse rate axis, and the center is the reference pulse rate. In the case where attention is paid to a certain calculation time, the horizontal axis indicates the range that the calculated pulse rate can take centering on the reference pulse rate.

In the first setting method, the window width “W” is linearly increased with respect to the value of the number of consecutive inappropriate determinations “N”. Specifically, for example, the window width “W (N)” is set according to the following equation (1).

According to Equation (1), when N = 0, the window width is set to the initial window width “W ₀ ” (W (0) = W ₀ ). When N = 1, the window width is set to “2W ₀ ” wider than the initial window width “W ₀ ” (W (1) = 2W ₀ ). When N = 2, the window width is set to “3W ₀ ” wider than “2W ₀ ” (W (2) = 3W ₀ ).

  FIG. 6 is an explanatory diagram of a second window width setting method. In the first setting method shown in FIG. 5, the window width “W” is linearly increased as the value of the number of consecutive inappropriate determinations “N” increases. The width will increase excessively.

Usually, in a scene where the pulse rate of the subject changes rapidly, the change in the pulse rate tends to be moderate after the pulse rate changes once abruptly. The window is set assuming a range in which the pulse rate can fluctuate, but it is rare that the subject's pulse rate continuously changes by the maximum width of the window. Therefore, it is effective to reduce the increase in the window width as the value of the number of consecutive inappropriate determinations “N” increases. Specifically, for example, the window width “W (N)” is set according to the following equation (2).

According to equation (2), when N = 0, the window width is set to the initial window width “W ₀ ” (W (0) = W ₀ ). For N = 1, the change of the window width as _{"ΔW (1) = W 0} /2", is set to a window width _{"W 0 (1 + 1/} 2)" (W (1) = W 0 ( 1 + 1/2)). N = 2, the general the change in window width as _{"ΔW (2) = W 0} /3", setting the window width _{"W 0 (1 + 1/} 2 + 1/3)" (W (2) = W ₀ (1 + 1/2 + 1/3)). That is, according to Expression (2), the degree of increase in the window width is decreased by “1 / (N + 1)”.

3. Functional Configuration FIG. 7 is a block diagram showing an example of a functional configuration of the pulsometer 1 common to each embodiment. The pulsometer 1 includes a pulse wave sensor 10, a body motion sensor 20, a pulse wave signal amplification circuit unit 30, a pulse waveform shaping circuit unit 40, a body motion signal amplification circuit unit 50, and a body motion waveform shaping circuit unit 60. An A / D (Analog / Digital) conversion unit 70, a processing unit 100, an operation unit 200, a display unit 300, a notification unit 400, a communication unit 500, a clock unit 600, and a storage unit 700. It is prepared for.

  The pulse wave sensor 10 is a sensor that measures the pulse wave of the subject to whom the pulse meter 1 is attached, and is configured to include, for example, a photoelectric pulse wave sensor. The pulse wave sensor 10 detects a volume change caused by the inflow of blood flow into the body tissue as a pulse wave signal and outputs it to the pulse wave signal amplification circuit unit 30.

  The pulse wave signal amplification circuit unit 30 is an amplification circuit that amplifies the pulse wave signal input from the pulse wave sensor 10 with a predetermined gain. The pulse wave signal amplifier circuit unit 30 outputs the amplified pulse wave signal to the pulse waveform shaping circuit unit 40 and the A / D converter 70.

  The pulse waveform shaping circuit unit 40 is a circuit unit that shapes the pulse wave signal amplified by the pulse wave signal amplification circuit unit 30, and includes a circuit that removes a high-frequency noise component, a clipping circuit, and the like. The processing unit 100 determines whether or not a pulse wave has been detected based on the pulse waveform shaped by the pulse waveform shaping circuit unit 40.

  The body motion sensor 20 is a sensor for capturing the movement of the subject to whom the pulse meter 1 is attached, and includes an acceleration sensor and the like. The body motion sensor 20 corresponds to a body motion detection unit that detects the body motion of the subject.

  The body motion signal amplification circuit unit 50 includes an amplification circuit that amplifies the body motion signal input from the body motion sensor 20 with a predetermined gain. The body motion signal amplification circuit unit 50 outputs the amplified body motion signal to the body motion waveform shaping circuit unit 60 and the A / D conversion unit 70.

  The body motion waveform shaping circuit unit 60 is a circuit unit that shapes the body motion signal amplified by the body motion signal amplification circuit unit 50. The body motion waveform shaping circuit unit 60 is a circuit that removes high-frequency noise components, a gravitational acceleration component, and other components. A circuit for determining whether or not, a clipping circuit, and the like. The processing unit 100 determines whether or not body motion is detected based on the body motion waveform shaped by the body motion waveform shaping circuit unit 60.

  The A / D conversion unit 70 converts the analog pulse wave signal amplified by the pulse wave signal amplification circuit unit 30 and the analog body motion signal amplified by the body motion signal amplification circuit unit 50 to predetermined amounts, respectively. It is sampled and digitized at sampling time intervals and converted to a digital signal. Then, the converted digital signal is output to the processing unit 100.

  The processing unit 100 is a control device and arithmetic device that comprehensively controls each unit of the pulse meter 1 according to various programs such as a system program stored in the storage unit 700, and is a CPU (Central Processing Unit) or DSP (Digital Signal). Processor). The processing unit 100 performs a pulse rate measurement process according to the pulse rate measurement program 710 stored in the storage unit 700, calculates and measures the pulse rate of the subject wearing the pulse meter 1, and causes the display unit 300 to display the pulse rate. Take control.

  The processing unit 100 includes, for example, a pulse rate calculation unit 120, a window setting unit 130, an inappropriate determination continuous frequency measurement unit 150, a pulse rate suitability determination unit 160, a display control unit 170, and a reference pulse rate update unit 180. As a functional part. However, these functional units are merely examples, and all the functional units do not necessarily have to be essential constituent requirements.

  The pulse rate calculation unit 120 performs a process of removing body motion noise components from the pulse wave signal (pulse wave data) using the body motion signal (body motion data) input from the A / D conversion unit 70. Then, the pulse rate of the subject is calculated using the extracted pulsation component (beat data).

  The window setting unit 130 sets a window used by the pulse rate suitability determining unit 160 for determining the suitability of the calculated pulse rate 790. The window setting unit 130 has a window width setting unit 140. Then, based on the window width 750 set by the window width setting unit 140 and the latest reference pulse rate 780, the window lower limit value 760 and the window upper limit value 770 are calculated.

  The window width setting unit 140 uses the window width setting data 720 stored in the storage unit 700 to set the window width according to the above principle. The window width setting unit 140 corresponds to a variation allowable width setting unit.

  The improper determination continuous frequency measurement unit 150 counts the continuous number of times that the calculated pulse rate 790 is determined to be inappropriate by the pulse rate appropriateness determination unit 160 (inappropriate determination continuous frequency).

  The pulse rate suitability determining unit 160 determines the suitability of the calculated pulse rate 790 calculated by the pulse rate calculating unit 120 using the window set by the window setting unit 130.

  The display control unit 170 controls the display of the pulse rate on the display unit 300 based on the determination result of the pulse rate suitability determination unit 160. Specifically, when the calculated pulse rate 790 is determined to be appropriate by the pulse rate suitability determining unit 160, the display unit 300 controls the display unit 300 to display the calculated pulse rate 790 as a measured pulse rate (measurement result). On the other hand, when the calculated pulse rate 790 is determined to be inappropriate by the pulse rate suitability determining unit 160, the latest reference pulse rate 780 is displayed and controlled on the display unit 300 as the measured pulse rate (measurement result).

  When the calculated pulse rate 790 is determined to be appropriate by the pulse rate suitability determining unit 160, the reference pulse rate update unit 180 updates the reference pulse rate 780 with the calculated pulse rate 790.

  The operation unit 200 is an input device having a button switch or the like, and outputs a signal of a pressed button to the processing unit 100. By operating the operation unit 200, various instructions such as a pulse rate measurement instruction are input. The operation unit 200 corresponds to the operation button 5 in FIG.

  The display unit 300 includes an LCD (Liquid Crystal Display) or the like, and is a display device that performs various displays based on a display signal input from the processing unit 100. Various kinds of biological information (pulse rate, exercise intensity, calorie consumption, etc.) are displayed on the display unit 300. The display unit 300 corresponds to the liquid crystal display 4 in FIG.

  The notification unit 400 includes a speaker, a piezoelectric vibrator, and the like, and is a notification device that performs various notifications based on a notification signal input from the processing unit 100. For example, various notifications are given to the subject by outputting an alarm sound from a speaker or vibrating a piezoelectric vibrator.

  The communication unit 500 is a communication device for transmitting / receiving information used inside the device to / from an external information processing device such as a personal computer (PC) under the control of the processing unit 100. As a communication method of the communication unit 500, a form of wired connection via a cable compliant with a predetermined communication standard, a form of connection via an intermediate device also used as a charger called a cradle, or short-range wireless communication is used. Various systems such as a wireless connection type can be applied.

  The clock unit 600 includes a crystal oscillator including a crystal resonator and an oscillation circuit, and is a time measuring device that measures time. The time measured by the clock unit 600 is output to the processing unit 100 as needed.

  The storage unit 700 is configured by a storage device such as a ROM (Read Only Memory), a flash ROM, or a RAM (Random Access Memory). The system program of the pulse meter 1, the pulse rate measurement function, the exercise intensity measurement function, and the calorie measurement function Various programs and data for realizing various functions are stored. In addition, it has a work area for temporarily storing data being processed and results of various processes.

3-1. First Example In the first example, the pulse rate measurement program 710 executed as a pulse rate measurement process (see FIG. 8) is stored in the storage unit 700 of the pulse meter 1 as a program. Further, as data, window width setting data 720, initial window width 730, unsuitable determination continuous number of times 740, window width 750, window lower limit value 760, window upper limit value 770, reference pulse rate 780, calculation The pulse rate 790 is stored.

  The window width setting data 720 is data used by the window width setting unit 140 to set the window width. For example, this includes data such as a window width model function such as Expression (1) or Expression (2) described in the above principle, or a table in which the number of consecutive inappropriate determinations is associated with the window width.

3-2. Process Flow FIG. 8 is a flowchart showing the flow of the pulse rate measurement process executed in the pulse meter 1 when the processor 100 reads out the pulse rate measurement program 710 stored in the storage unit 700.

  First, the processing unit 100 performs initial setting (step A1). Specifically, “0” is set as the initial value of the inappropriate determination continuous count 740. In addition, a predetermined value (for example, a pulse rate at rest) is set as an initial value of the reference pulse rate 780.

  Next, the processing unit 100 acquires detection results of the pulse wave sensor 10 and the body motion sensor 20 (step A3). Then, the pulse rate calculation unit 120 calculates the pulse rate of the subject using the detection result of the pulse wave signal of the pulse wave sensor 10 and the detection result of the body motion sensor 20, and the calculation result of the storage unit 700 is calculated based on the calculation result. The pulse rate 790 is updated (step A5).

  Thereafter, the window width setting unit 140 sets the window width 750 using the window width setting data 720 based on the initial window width 730 and the inappropriate determination continuous count 740 stored in the storage unit 700, and the storage unit 700 (Step A7).

  Next, window setting unit 130 calculates window lower limit value 760 and window upper limit value 770 using window width 750 and reference pulse rate 780 stored in storage unit 700 and stores them in storage unit 700 (step A9). ).

  Thereafter, the pulse rate suitability determination unit 160 determines whether or not the calculated pulse rate 790 is equal to or greater than the window lower limit value 760 (step A11). If this condition is satisfied (step A11; Yes), the calculated pulse rate 790 is determined. Is less than or equal to the window upper limit value 770 (step A13). If this condition is satisfied (step A13; Yes), the calculated pulse rate 790 is determined to be appropriate (step A15).

  In this case, the display control unit 170 controls the display unit 300 to display the calculated pulse rate 790 as the measured pulse rate (step A17). The reference pulse rate updating unit 180 updates the reference pulse rate 780 with the calculated pulse rate 790 (step A19). Further, the inappropriate determination continuous count measuring unit 150 resets the inappropriate determination continuous count 740 of the storage unit 700 (step A21).

  On the other hand, if it is determined in step A11 or step A13 that the condition is not satisfied (step A11; No or step A13; No), the pulse rate appropriateness determination unit 160 determines that the calculated pulse rate 790 is inappropriate ( Step A23).

  In this case, the display controller 170 controls the display 300 to display the reference pulse rate 780 as the measured pulse rate (step A25). Further, the inappropriate determination continuous count measuring unit 150 increments the inappropriate determination continuous count 740 of the storage unit 700 by “1” (step A27).

  After step A21 or A27, the processing unit 100 determines whether or not to end the pulse rate measurement (step A29). For example, it is determined whether or not an instruction operation for ending pulse rate measurement has been performed by the subject via the operation unit 200. If it is determined not to end the measurement (step A29; No), the process returns to step A3. Moreover, when it determines with complete | finishing a measurement (step A29; Yes), a pulse rate measurement process is complete | finished.

3-3. Operational Effect In the pulsometer 1, the pulse rate of the subject is calculated by the pulse rate calculation unit 120. Also, based on whether or not the calculated pulse rate calculated by the pulse rate calculating unit 120 is included in a given window, the suitability of the calculated pulse rate is determined by the pulse rate appropriateness determining unit 160. Then, the window width, which is the window width, is set by the window width setting unit 140 based on the value of the number of consecutive negative determinations (improper determinations) by the pulse rate appropriateness determination unit 160.

  Rather than setting the window width fixedly, it is possible to cope with changes in the pulse rate by variably setting the window width based on the value of the number of consecutive inappropriate determinations. More specifically, the window width can be made to follow the change in the pulse rate by increasing the window width as the value of the number of consecutive inappropriate determinations increases.

  In this case, for example, by linearly increasing the window width with respect to the value of the number of consecutive inappropriate determinations, even if a sudden change in the pulse rate occurs at the start of exercise or at the stop of exercise, etc. The pulse rate can be reliably captured in the window.

  Further, by reducing the increase in the window width as the value of the number of consecutive inappropriate determinations is increased, it is possible to prevent the window from becoming excessively wide and to reduce the possibility that an abnormal value is captured by the window. Even if the pulse rate of the subject changes suddenly, the change in the pulse rate tends to become gradual thereafter. For this reason, it is possible to determine suitability by setting a window corresponding to the change tendency of the actual human pulse rate.

  In addition, by making the window narrow in the initial setting, even if an abnormal value of the calculated pulse rate is suddenly obtained, this abnormal value can be rejected. In addition, by increasing the window width as the number of consecutive inappropriate judgments increases, it is possible to capture the calculated pulse rate at a relatively early stage even when the pulse rate changes rapidly. (Real time property) can be improved.

4). 2nd Example 2nd Example determines the reliability of the calculation result of the pulse rate by the pulse rate calculation part 120, and uses the window demonstrated in 1st Example, and the reliability of the calculation result of a pulse rate. This is an embodiment for determining the suitability of the calculated pulse rate.

4-1. Configuration In the second embodiment, the processing unit 100 in FIG. 7 includes a reliability determination unit (not shown) that determines the reliability of the calculation result of the pulse rate calculation unit 120. The reliability determination unit determines the reliability of the calculation result based on, for example, a signal-to-noise ratio of the pulse wave signal detected by the pulse wave sensor 10 (hereinafter referred to as “Signal to Noise ratio”). .

  In this case, the pulse rate suitability determining unit 160 determines that the calculated pulse rate 790 is appropriate when the SN ratio calculated by the reliability determining unit satisfies a predetermined threshold condition and the calculated pulse rate 790 is included in the window. judge. In other cases, the calculated pulse rate 790 is determined to be inappropriate.

4-2. Process Flow FIG. 9 is a flowchart showing a flow of a second pulse rate measurement process executed by the processing unit 100 in place of the pulse rate measurement process of FIG. 8 in the second embodiment. In addition, about the step same as a pulse rate measurement process, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  After calculating the pulse rate in step A5, the processing unit 100 calculates the SN ratio of the pulse wave signal detected by the pulse wave sensor 10 (step B6). The SN ratio is calculated as follows, for example.

Frequency decomposition processing is performed on the digitized pulse wave signal (pulse wave data). Then, the base line having the maximum spectrum value is selected, and the base line is set as the pulse base line indicating the pulse of the subject. Further, among the baselines excluding the baseline included in the predetermined range in the vicinity of the pulse baseline, for example, the baseline having the second largest spectrum value is selected as the noise baseline. Then, “SN ratio = P _S / P _N ” is calculated using the spectral value “P _S ” of the pulse baseline and the spectral value “P _N ” of the noise baseline.

  In a situation where a base line with a large spectrum value is mixed and it is difficult to distinguish between a signal component and a noise component, the reliability of the pulse rate calculated based on the result of the frequency decomposition processing is lowered. In such a situation, the S / N ratio of the pulse wave signal tends to be small. Therefore, a threshold value for the SN ratio is set, and when the SN ratio exceeds the threshold value, it is determined that the reliability of the pulse rate calculation result is high.

  In this case, the pulse rate suitability determination unit 160 determines whether or not the SN ratio calculated in step B6 is equal to or greater than a predetermined high reliability threshold after step A9 (step B10). If this condition is satisfied (step B10; Yes), it is estimated that the reliability of the pulse rate calculation result will be high, and the process proceeds to determination using a window (steps A11 and A13).

  On the other hand, if it is determined in step B10 that the SN ratio has not reached the high reliability threshold (step B10; No), the processing unit 100 estimates that the reliability of the pulse rate calculation result will be low, It is determined that the calculated pulse rate is inappropriate (step A23).

4-3. Effects In the second embodiment, the calculated pulse rate is determined to be appropriate when the signal-to-noise ratio of the pulse wave signal satisfies a predetermined threshold condition and the calculated pulse rate is included in the window. By adding not only the window but also the reliability of the calculation result of the pulse rate to the determination criterion, the accuracy of determining the suitability of the calculated pulse rate can be further improved.

5. Modifications Embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be changed as appropriate without departing from the spirit of the present invention. Hereinafter, modified examples will be described.

5-1. Biological Information Processing Device In the above-described embodiment, a wristwatch type pulsometer has been described as an example of the biological information processing device, but a biological information processing device to which the present invention is applicable is not limited thereto. For example, the present invention can be applied to a finger-mounted pulse meter that is mounted on a fingertip and measures a pulse. Further, the pulse wave signal detection method is not limited to the detection method using light, and may be a detection method using ultrasonic waves or a detection method using electrocardiogram.

5-2. Body Motion Detection Unit In the above embodiment, the body motion sensor that is the body motion detection unit has been described as including an acceleration sensor. However, the body motion detection unit may include other sensors instead of the acceleration sensor. It is good. For example, the body motion sensor may be configured to include a gyro sensor, and the body motion of the subject may be detected based on the angular velocity detected by the gyro sensor. Of course, it may be configured to have both an acceleration sensor and a gyro sensor, and the body movement of the subject may be detected using the detection results of these sensors together.

5-3. Window Width Setting Criteria In the above embodiment, the window width setting criterion is the number of consecutive negative determinations based on the appropriateness determination of the pulse rate (the number of inappropriate determination continuous times). However, the window width setting standard is not limited to this.

  For example, even if the duration for which the calculated pulse rate is determined to be inappropriate in the suitability determination (hereinafter referred to as “inappropriate determination duration”) is measured, and the window width is set based on the value of the inappropriate determination duration Good. In other words, the window width may be set based on how long the inappropriateness determination is made by the pulse rate appropriateness determination unit 160 for a setting criterion.

  In addition, the frequency at which the calculated pulse rate is determined to be inappropriate in the appropriateness determination in the past predetermined period (hereinafter referred to as “inappropriate determination frequency”) is measured, and the window width is set based on the value of the inappropriate determination frequency. Also good. The past predetermined period can be set as appropriate. For example, the measurement period is 10 times retroactively from the present, and the inappropriate determination frequency in the measurement period is measured.

  In the same manner as in the above embodiment, when these setting criteria are used, the window width may be increased as the improper determination duration value increases or as the improper determination frequency value increases. . Also in this case, the window width is linearly increased with respect to the value of the inappropriate determination duration or the inappropriate determination frequency (for example, Expression (1)), or the degree of increase in the window width is set to the value of the inappropriate determination duration or the inappropriate determination frequency. A method of reducing (for example, Expression (2) or Expression (3)) can be applied in the same manner.

5-4. Window Width Setting Method The window width setting method described in the above embodiment is merely an example, and can be set as appropriate. For example, it is possible to set the window width according to the following equation (3) instead of equation (2).

  According to Equation (3), the window width is increased while the window width increase degree is decreased by “½” in accordance with a value such as the number of consecutive inappropriate determinations. Alternatively, for example, the window width may be increased logarithmically with respect to a value such as the number of consecutive inappropriate determinations.

5-5. Window In the above embodiment, a range having the same width in the height direction with the reference pulse rate as a reference is defined as a window. However, a range having different widths in the height direction with reference to the reference pulse rate may be defined as a window. That is, the window width in the upper direction for capturing a pulse rate higher than the reference pulse rate may be different from the window width in the lower direction for capturing a pulse rate lower than the reference pulse rate. However, in this case as well, there is no change in setting the window width for each of the height directions based on any one of the number of consecutive inappropriate determinations, the inappropriate determination duration, and the inappropriate determination frequency.

5-6. In the second embodiment, the reliability of the pulse rate calculation result is determined based on the signal-to-noise ratio (SN ratio) of the pulse wave signal detected by the pulse wave sensor 10. explained. However, the SN ratio is only one index for determining reliability, and it is possible to determine reliability based on other indices.

  For example, the reliability of the calculation result may be determined based on the strength (signal strength) of the pulse wave signal. Specifically, if the amplitude of the pulse wave signal is extremely small, there is a high possibility that the pulse wave of the subject cannot be captured well, so it is determined that the reliability of the calculated pulse rate is low be able to. In addition, when the pulse wave signal suddenly swings out, there is a high possibility that noise is mixed, and in this case as well, it can be determined that the reliability of the calculation result is low. Of course, it is also possible to determine the reliability of the calculation result by using both the signal-to-noise ratio of the pulse wave signal and the signal intensity.

5-7. Reference Pulse Rate In the above embodiment, the latest calculated pulse rate determined to be appropriate by the suitability determination is set as the reference pulse rate. That is, when it was determined that the calculated pulse rate is appropriate, the process of updating the reference pulse rate with the calculated pulse rate has been described as being repeated every time the pulse rate is calculated.

  However, the pulse rate that can be set as the reference pulse rate is not limited to this. For example, an average value or median value of calculated pulse rates determined to be appropriate in the past predetermined period (for example, a period corresponding to the past 5 calculation times) from the current calculation time may be obtained and set as the reference pulse rate.

  1 pulse meter, 10 pulse wave sensor, 20 body motion sensor, 30 pulse wave signal amplification circuit unit, 40 pulse waveform shaping circuit unit, 50 body motion signal amplification circuit unit, 60 body motion waveform shaping circuit unit, 70 A / D conversion Unit, 100 processing unit, 200 operation unit, 300 display unit, 400 notification unit, 500 communication unit, 600 clock unit, 700 storage unit

Claims (8)

A pulse rate calculator for calculating the pulse rate of the subject;
A pulse rate suitability determination unit that determines the suitability of the calculated pulse rate based on whether or not the calculated pulse rate calculated by the pulse rate calculation unit is included in a given fluctuation allowable range;
A variation allowable width setting unit that sets a variation allowable width that is a width of the variation allowable range based on any one of the number of consecutive negative determinations by the pulse rate suitability determination unit, the duration, and the frequency,
A biological information processing apparatus comprising: The fluctuation tolerance setting unit sets the fluctuation tolerance so that the fluctuation tolerance is increased as the value increases.
The biological information processing apparatus according to claim 1. The fluctuation allowable width setting unit linearly increases the fluctuation allowable width with respect to the value.
The biological information processing apparatus according to claim 2. The fluctuation allowable width setting unit reduces the increase degree of the fluctuation allowable width as the value increases.
The biological information processing apparatus according to claim 2. A reliability determination unit that determines the reliability of the calculation result of the pulse rate calculation unit;
The pulse rate suitability determination unit determines the suitability of the calculated pulse rate using the variation allowable range and the reliability.
The biological information processing apparatus according to any one of claims 1 to 4. The reliability determination unit determines the reliability based on a signal-to-noise ratio of a signal in which the pulse wave of the subject is detected,
The pulse rate suitability determining unit determines that the calculated pulse rate is appropriate when the signal-to-noise ratio satisfies a predetermined threshold condition and the calculated pulse rate is included in the fluctuation allowable range,
The biological information processing apparatus according to claim 5. The variation allowable range is a range determined based on a given reference pulse rate,
When the calculated pulse rate is determined to be appropriate by the pulse rate suitability determining unit, the apparatus further comprises a reference pulse rate updating unit that updates the reference pulse rate with the calculated pulse rate.
The biological information processing apparatus according to any one of claims 1 to 6. Calculating the subject's pulse rate;
Determining the suitability of the calculated pulse rate based on whether or not the calculated calculated pulse rate is included in a given allowable fluctuation range;
Setting a variation tolerance width that is a width of the variation tolerance range based on any one of the number of consecutive negative judgments by the suitability judgment, the duration, and the frequency;
A biological information processing method comprising:

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