JP2006238971A - Cycle calculator and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To calculate appropriately a standard cycle that corresponds to heart rate or pulse rate of a subject. <P>SOLUTION: A cycle calculator 1 is provided which is arranged on a subject detachably. A pulse wave sensor 10 measures a standard cycle, and an acceleration sensor 90 measures kinetic amount of the subject that correlates with the standard cycle. A CPU 70 corrects the standard cycle measured by the pulse wave sensor 10 using the kinetic amount measured by the acceleration sensor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a period calculation device and a program for calculating a reference period.

Conventionally, a blood vessel is irradiated with light, a pulse wave is identified based on a change in the amount of reflected or transmitted light according to the pulsation of the blood vessel, and the cycle of the identified pulse wave (hereinafter simply referred to as a pulse wave cycle). ) Has been proposed. In this cycle calculation device, n pulse wave cycles are measured, the measured pulse wave cycles are arranged in order of magnitude, and a pulse wave cycle (hereinafter referred to as a central cycle) that comes to the center in the arranged order. The pulse rate is calculated by being used (for example, refer patent document 1). As a result, a pulse wave period that is less influenced by noise is used among the n pulse wave periods measured, and thus it appears that the pulse rate corresponding to the pulse wave period is calculated with high accuracy.
JP 2002-28138 A

  However, in the period calculation device, one or a plurality of noises (for example, P3 which is between P2 and P4 pulse wave periods shown in FIG. 13) are included in the original pulse wave period. When the wave period (for example, P2-P4 pulse wave period shown in FIG. 13) is divided, the original pulse wave period cannot be the central period, and the original pulse wave period is the pulse rate. It is difficult to calculate the pulse rate with high accuracy.

  Further, when the pulse wave passes through the filter circuit, a part of the pulse wave (for example, the pulse wave of P4-5 shown in FIG. 13 or the pulse wave of the dotted line portion) may be excluded. Waves were not used to calculate the pulse rate, and it was difficult to calculate the pulse rate with high accuracy.

  On the other hand, when the applicant sets a reference period and the next period, which is the next period of the reference period, belongs to the specific range that is within the range of the upper limit value and the lower limit value for the reference period, An apparatus for calculating the next period as a pulse wave period is proposed. Thereby, when the next cycle does not belong to the specific range, the next cycle is not calculated as a pulse wave cycle.

  Therefore, a short period (for example, P2-P3; P3 shown in FIG. 13 is a pulse wave due to noise) in which the next period does not belong to the specific range, or a long period (for example, FIG. 11 in which the next period exceeds the specific range). P4-5; original P4-5 is removed by a filter circuit or the like) is not set as a pulse wave period, so that it seems that an appropriate pulse rate is calculated.

  However, the apparatus calculates the next cycle as a pulse wave cycle depending on whether or not the next cycle belongs to a specific range that is within a range of an upper limit value and a lower limit value with respect to the reference cycle. For this reason, the apparatus cannot appropriately calculate the next period as a pulse wave period unless the reference period is appropriate.

  Specifically, since the apparatus includes a filter circuit, a pulse wave (for example, P4-5 shown in FIG. 13) that should originally exist may be removed. For this reason, when the original pulse wave (for example, P4-5 shown in FIG. 13) is removed, the above-described apparatus can detect the interval between the pulse waves in the state where the original pulse wave is removed (for example, P4 shown in FIG. 13). -P5) must be a reference period, and the next period may be erroneously calculated by using the reference period.

  Accordingly, it has been desired to develop a technique that can appropriately set the reference period that is a basis for calculating the pulse rate.

  Therefore, the present invention has been made in view of the above points, and an object thereof is to provide a period calculation device and a program that can appropriately calculate a reference period.

  In order to solve the above-mentioned problem, the present invention is a period calculation device that is detachably attached to a subject, and a second sensor that measures a subject's momentum correlated with a reference period measured by the first sensor; And a correction unit that corrects the reference period measured by the first sensor using the value of the momentum measured by the second sensor.

  According to such a feature of the present invention, even if the measured reference period is greatly deviated from the original reference period (hereinafter referred to as the original reference period), the momentum value measured by the second sensor is used. The measured reference period can be brought close to the original reference period.

  In the above invention, the correction value may be corrected using the momentum value measured by the second sensor when the reference period measured by the first sensor does not fall within the predetermined range. .

  In the said invention, a 1st sensor measures the reference | standard period which is the space | interval from the one peak of the amplitude of a test subject's pulse wave to the next peak, and the specific range which is between the minimum and the upper limit with respect to a reference | standard period. A range setting means for setting and a period calculation unit for calculating the next period as a pulse wave period when the next period, which is the next period relative to the reference period measured by the first sensor, belongs to the specific range. May be.

  In the above invention, the reference period is the pulse rate of the subject or a period corresponding to the heart rate, the momentum is a composite value of accelerations acting in three axis directions orthogonal to each other, and the correction unit is configured to measure the accelerations of a large number of subjects. Using the approximate expression calculated from the relationship between the combined value of the multiple and the pulse rate or heart rate of the large number of subjects, and the combined value of the acceleration measured by the second sensor. The reference period may be corrected.

  According to the characteristics of the present invention, it is possible to provide a period calculation device and a program that can appropriately calculate a reference period.

[First Embodiment]
(Basic configuration of period calculation device)
The period calculation device 1 according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an internal block of a period calculation device 1 in the present embodiment. The period calculation device 1 in the present embodiment includes a pulse wave sensor 10, a detection unit 20, a bandpass filter unit 30, a notification unit 40, a RAM 50, a ROM 60, and a CPU 70.

  The pulse wave sensor 10 irradiates light, receives light reflected from the skin or the like by the light, and measures a pulse wave corresponding to the amount of received light. The detection unit 20 detects the pulse wave measured by the pulse wave sensor 10. The band pass filter unit 30 extracts only a pulse wave having a specific frequency component from the pulse wave detected by the detection unit 20.

  If the pulse wave cycle is not calculated by the CPU 70 described later, the notification unit 40 notifies that fact. Moreover, the alerting | reporting part 40 outputs the pulse rate etc. corresponding to a pulse wave period and a pulse wave period, for example, is comprised from a liquid crystal display device, a speaker, etc. The RAM 50 temporarily stores data. The ROM 60 stores a program for operating the cycle calculation device 1 and the like.

  The CPU 70 executes processing based on a program stored in the ROM 60, and includes a peak interval specifying unit 71, a next peak interval specifying unit 72, a range setting unit 73, and a period calculating unit 74. Yes.

  The peak interval specifying unit 71 specifies an interval from one peak to the next peak of the amplitude of the pulse wave as a peak interval (t1, t2,... Shown in FIG. 3 to be described later; the next cycle that is the next cycle of the reference cycle). To do. The next peak interval specifying unit 72 is a peak interval specified by the peak interval specifying unit 71 (for example, t1 shown in FIG. 3C described later) and a continuous peak interval (for example, FIG. (T2) shown in (c) is specified as one peak interval (for example, t1 + t2 shown in FIG. 3 (c) described later, the next cycle that is the next cycle of the reference cycle).

  The range setting unit 73 sets a specific range TA (see FIG. 3A described later) that is between a lower limit and an upper limit with respect to the reference period T (see FIG. 3A described later). Examples of the reference period T include a preset pulse wave period, a pulse wave period at the immediately preceding peak interval, an average pulse wave period at each peak interval, and the like. The reference period T in the present embodiment will be described as a pulse wave period calculated immediately before a predetermined peak interval.

  When the peak interval specified by the peak interval specifying unit 71 (for example, t1 shown in FIG. 3B described later) belongs to the specific range TA, the cycle calculating unit 74 calculates the peak interval as a pulse wave cycle. To do. Further, when the peak interval specified by the next peak interval specifying unit 72 (for example, t1 + t2 shown in FIG. 3C described later) belongs to the specific range TA, the period calculating unit 74 converts the peak interval into a pulse wave. Calculated as a period.

  Further, in the period calculation unit 74, a plurality of peak intervals (for example, t1 + t2, t1 + t2 + t3 shown in FIG. 3D described later) specified by the peak interval specifying unit 71 or the next peak interval specifying unit 72 belong to the specific range TA. In this case, the peak interval (for example, t1 + t2) closest to the reference cycle T among the plurality of peak intervals is calculated as the pulse wave cycle.

  In addition, the period calculation unit 74 includes a plurality of peak intervals specified by the peak interval specifying unit 71 or the next peak interval specifying unit 72 (for example, t1, t1 + t2 shown in FIG. 4C described later) belonging to the specific range TA. If not, the end point of the first peak interval (for example, t1) among the plurality of peak intervals is set as the start point of the reference period T (for example, FIGS. 4D and 4G described later).

(Operation of period calculation device)
Hereinafter, a period calculation method that is an operation of the period calculation device will be described with reference to the drawings. FIG. 2 is a diagram illustrating a period calculation method in the present embodiment. As shown in FIG. 2, in step 1, the detection unit 20 detects a signal output from the pulse wave sensor 10 as a pulse wave. Thereafter, the band pass filter unit 30 extracts only a specific frequency component from the pulse wave detected by the detection unit 20.

  In step 2, the CPU 70 specifies an interval from one peak of the amplitude of the pulse wave to the next peak as a peak interval (t1, t2,... Shown in FIG. 3 described later). In step 3, the CPU 70 performs a period calculation method using the specified peak interval. In step 4, the CPU 70 confirms whether or not the pulse wave cycle has been calculated. Further, the CPU 70 proceeds to the process of step 5 when the pulse wave period is calculated, and proceeds to the process of step 6 when the pulse wave period is not calculated.

  In step 5, the CPU 70 outputs a command for instructing to output the pulse rate corresponding to the calculated pulse wave cycle to the notification unit 40. The notification unit 40 displays the pulse rate and the like based on the command output by the CPU 70. In step 6, the CPU 70 proceeds to the process of step 7 when the pulse wave cycle has not been calculated continuously n times or more, and proceeds to the process of step 1 when the pulse wave cycle has not been calculated within n times. Return.

  In step 7, the CPU 70 outputs to the notification unit 40 a command for instructing that the process is an error. The notification unit 40 displays specific information (for example, characters such as “please attach the pulse wave sensor 10 to an appropriate position”) based on the command output by the CPU 70.

  In step 8, the CPU 70 confirms whether an end condition (for example, an operation for ending the calculation of the pulse wave period is accepted) is satisfied. Further, the CPU 70 ends the process when the end condition is satisfied, and returns to the process of step 1 when the end condition is not satisfied.

  Next, the period calculation process in step 3 described above will be described. 3 and 4 are diagrams showing a state until the pulse wave cycle is calculated by the cycle calculation processing in step 3. This period calculation process is roughly divided into pattern 1 and pattern 2. Hereinafter, pattern 1 and pattern 2 will be described in detail.

(A) Pattern 1 As shown in FIG. 3A, first, the range setting unit 73 is between the previous pulse wave period T, which is the reference period, and the lower limit Tmin and the upper limit Tmax with respect to the pulse wave period T. A specific range TA is set. When the first peak interval t1 belongs to the specific range TA, the cycle calculating unit 74 calculates the peak interval t1 as a pulse wave cycle.

  On the other hand, as shown in FIG. 3B, when the first peak interval t1 (or t1 ′) does not belong to the specific range TA, the period calculation unit 74 uses the peak interval t1 (or t1 ′) as a pulse wave. Not calculated as a period.

  In this case, as shown in FIG. 3C, the next peak interval specifying unit 72 specifies the peak interval t1 and the continuous peak interval t2, which is the subsequent peak interval, as the peak interval (t1 + t2). Then, as shown in FIG. 3C, when the peak interval (t1 + t2) belongs to the specific range TA, the cycle calculation unit 74 calculates the peak interval (t1 + t2) as a pulse wave cycle.

  However, as shown in FIG. 3D, not only the peak interval (t1 + t2) but also the peak interval (t1 + t2 + t3) which is the sum of the peak interval (t1 + t2) and the subsequent continuous peak interval t3 belongs to the specific range TA. The period calculation unit 74 calculates the peak interval (t1 + t2) closest to the reference period T as the pulse wave period.

(B) Pattern 2 As shown in FIG. 4A, first, the range setting unit 73 is between the previous pulse wave period T, which is the reference period, and the lower limit Tmin and the upper limit Tmax with respect to the pulse wave period T. A specific range TA is set. As shown in FIGS. 4B and 4C, when the first peak interval t1 does not belong to the specific range TA, the next peak interval specifying unit 72 is the peak interval t1 and the subsequent peak interval. The continuous peak interval t2 is specified as the peak interval (t1 + t2).

  Thereafter, as shown in FIGS. 4C and 4D, when not only the first peak interval t1 but also the next specified peak interval (t1 + t2) does not belong to the specific range TA, the period calculation unit 74 Changes the end point of the first peak interval t1 to the start point of the reference period T (see FIG. 4G). Therefore, the first peak interval t1 is deleted.

  In the present embodiment, when the next specified peak interval (t1 + t2) exceeds the upper limit Tmax, the cycle calculating unit 74 changes the end point of the first peak interval t1 to the start point of the reference cycle T ( (Refer FIG.4 (d)).

  As shown in FIG. 4D, when the peak interval t2 does not belong to the specific range TA, the next peak interval specifying unit 72 sets the peak interval t2 and the continuous peak interval t3 that is the subsequent peak interval. It is specified as the peak interval (t2 + t3). Thereafter, as shown in FIGS. 4E and 4F, when the peak interval (t2 + t3) belongs to the specific range TA, the period calculation unit 74 calculates the peak interval (t2 + t3) as a pulse wave period.

  Here, the period calculation unit 74 calculates an average value (seconds) of a plurality of pulse wave periods calculated using the pattern 1 or the pattern 2, and divides 60 by the average value to thereby calculate the pulse in one minute. The number (bpm) is calculated.

(Function and effect)
According to such a feature of the present invention, the peak interval (t1 + t2), which is the sum of the peak interval (eg, t1 shown in FIG. 3) and the subsequent continuous peak interval (eg, t2 shown in FIG. 3), is in a specific range. When belonging to the inner TA, the peak interval (t1 + t2) is calculated as the pulse wave period. As a result, a peak interval that is so short that it does not belong to the specific range TA, that is, a peak interval (t1) that is likely to be the interval between one peak of the original pulse wave and the noise peak is not calculated as the pulse wave period. In addition, since the original peak interval (t1 + t2), which is the sum of the peak interval t1 and the subsequent continuous interval t2, is calculated as the pulse wave cycle, an appropriate pulse wave cycle is calculated even if noise is included in the pulse wave. be able to.

  Furthermore, the peak interval (for example, t1 ′ shown in FIG. 3) that is the interval between the peaks existing before and after the pulse wave eliminated by the bandpass filter unit 30 or the like may be wider than the original peak interval. In this case, when the wide peak interval (t1 ′) exceeds the specific range TA, the wide peak interval is not calculated as the pulse wave period. The period can be calculated.

  Further, even if a plurality of peak intervals (for example, t1 + t2, t1 + t2 + t3 shown in FIG. 3) belong to the specific range TA, a peak interval closest to the reference period T (for example, t1 + t2 shown in FIG. 3) among the plurality of peak intervals. ) Is calculated as the pulse wave period, the peak interval (t1 + t2) closer to the original period can be calculated as the pulse wave period.

  Furthermore, when a plurality of peak intervals (for example, t1, t1 + t2 shown in FIG. 4) do not belong to the specific range TA, the end points of the first peak interval (for example, t1 shown in FIG. 4) among the plurality of peak intervals. Is the starting point of the reference period T. Accordingly, since it is determined again whether or not the next peak interval (t2) belongs to the specific range except the first peak interval (t1), a more appropriate pulse wave cycle can be calculated.

  Further, when the pulse wave period is not calculated, the fact is notified so that the measurer can reattach the position of the sensor that measures the pulse wave to a more appropriate position.

[Second Embodiment]
(Basic configuration of period calculation device)
In the first embodiment and the second embodiment, the reference period T (see FIGS. 3 and 4) is common in that it is the previous pulse wave period T. In the second embodiment, the reference period T is Furthermore, it differs in that it is corrected according to the momentum acting on the subject. Below, only a different point from 1st Embodiment is demonstrated, and it abbreviate | omits about description of a common part.

  FIG. 5 is a diagram showing an internal block of the period calculation device 1 in the present embodiment. Note that each unit included in the period calculation device 1 illustrated in FIG. 5 has the same function as each unit of the same name included in the cycle calculation device 1 illustrated in FIG.

  As shown in FIG. 5, the period calculation device 1 includes a correction unit 75, an acceleration sensor 80, and a detection unit 90 in addition to the configuration of the first embodiment.

  The acceleration sensor 80 constitutes a second sensor that measures the amount of exercise of the subject having a correlation with the period (reference period T) measured by the pulse wave sensor 10, the detection unit 20, and the CPU 70. This momentum may be the acceleration acting on the subject, the number of steps of the subject, the analysis result of the gas exhaled from the subject, and the like. The amount of exercise in the present embodiment is assumed to be acceleration acting on the subject. The pulse wave sensor 10, the detection unit 20, and the CPU 70 constitute a first sensor. The acceleration sensor 80 may be provided in a Holter electrocardiograph.

  The detection unit 90 detects the value of acceleration measured by the acceleration sensor 80.

  The CPU 70 includes a correction unit 75 that corrects the reference period measured by the pulse wave sensor 10 using the acceleration value measured by the acceleration sensor 80. For example, the correction unit 75 uses an approximate expression calculated from the relationship between the acceleration values of a large number of subjects and the pulse rate or heart rate of the large numbers of subjects, and a combined value of accelerations measured by the acceleration sensor 80. Thus, the reference period measured by the pulse wave sensor 10 is corrected.

  The correction value 77 may be corrected using the acceleration value measured by the acceleration sensor 80 when the reference period measured by the pulse wave sensor 10 does not fall within the predetermined range.

  FIG. 6A is a diagram illustrating a state where the pulse wave sensor 10 and the acceleration sensor 80 according to the present embodiment are attached to a subject. FIG. 6B is a diagram showing the direction of acceleration acting on the subject.

  As shown in FIG. 6A, the pulse wave sensor 10 is attached to the ear of the subject, and the acceleration sensor 80 is attached to the trunk of the subject. The acceleration sensor 80 may be attached to the subject's ear together with the pulse wave sensor 10.

  As shown in FIG. 6B, when the acceleration sensor 80 is attached to the subject, the acceleration sensor 80 measures acceleration in the directions of three axes orthogonal to each other. That is, the acceleration sensor 80 measures the x-axis acceleration ix along the subject's forward / backward direction, the y-axis acceleration iy along the subject's left-right direction, and the z-axis acceleration iz along the subject's vertical direction. The combined value of the acceleration ix, acceleration iy, and acceleration iz is itotal.

(Operation of period calculation device)
Next, reference cycle calculation processing 1 and reference cycle calculation processing 2 which are operations of the cycle calculation apparatus will be described with reference to the drawings. Below, it demonstrates in order of the reference period calculation process 1 and the reference period calculation process 2. FIG.

(1) Reference cycle calculation process 1
FIG. 7 is a diagram showing the reference cycle calculation process 1 in the present embodiment. As shown in FIG. 7, in step 11, the acceleration sensor 80 measures the acceleration (ix, iy, iz) of the subject acting on three axes orthogonal to each other.

In step 12, the correction unit 75 calculates the average value of the combined acceleration, which is the combined value of the accelerations (ix, iy, iz), as the combined acceleration itotal based on the measured accelerations (ix, iy, iz). . That is, when there are a plurality of synthetic accelerations (m in this case) at a predetermined time interval, and the average value of the plurality of synthetic accelerations at the predetermined time interval is the synthetic acceleration itotal, the synthetic acceleration itotal is expressed by the following formula 1. Can be expressed.

  In step 13, the correction unit 75 determines a provisional reference pulse rate for the combined acceleration itotal based on a previously set combined acceleration-pulse rate characteristic (approximate expression of equation 2 described later) and the calculated combined acceleration itotal. Is calculated. The temporary reference pulse rate is a temporary pulse rate for correcting the previous pulse rate corresponding to the reference period T to an optimum value. This provisional reference pulse rate can be expressed by an approximate expression of Expression 2 below.

Temporary reference pulse rate = a · itotal + b (a, b; constant)... Formula 2
In step 14, the correction unit 75 corrects the previous pulse rate based on the previous pulse rate and the provisional reference pulse rate, and sets the corrected pulse rate as the reference pulse rate. This reference pulse rate can be expressed by Equation 3 below.

Reference pulse rate = (A · Previous pulse rate + B · Temporary reference pulse rate) / (A + B) (A, B; constant) ... Equation 3
In addition, it is preferable that A is 2 and B is 1. Further, the correction unit 75 calculates the reference pulse rate by dividing the previous pulse rate and the provisional reference pulse rate according to the above equation 3, but the present invention is not limited to this, and multiple regression analysis and PLS analysis are performed. May be used to calculate the reference pulse rate based on the previous pulse rate, the combined acceleration itotal, the number of steps of the subject, and the analysis result of the gas component exhaled by the subject.

  In step 15, the correction unit 75 calculates the reference period T based on the calculated reference pulse rate. This reference period T can be expressed by the following Equation 4. It is assumed that the reference pulse rate is a unit of bpm and the reference period T is a unit of second.

Reference period T = 60 / reference pulse rate (Formula 4)
Here, in the cycle calculation process in the first embodiment, the CPU 70 sets the reference cycle T calculated by the above equation 4 as the previous pulse wave cycle (see FIG. 3 and FIG. 4), and next to the pulse wave cycle. The pulse wave cycle (next cycle) is calculated. Since the process until the next pulse wave period is calculated based on the set reference period T is the same as the above-described period calculation process (see FIGS. 3 and 4), detailed description thereof is omitted.

  Next, with reference to FIG. 8, a process until calculation of the combined acceleration-pulse rate characteristic (approximate expression) used in S13 will be described. FIG. 8 is a diagram illustrating a process until calculating a combined acceleration-pulse rate characteristic (approximate expression).

  In S <b> 21, the period calculation device 1 inputs a composite acceleration that is a composite value of accelerations acting on a predetermined number (n) of subjects and a pulse number of the predetermined number (n) of subjects who are exhibiting the combined acceleration. Prompt. The predetermined number (n) is a number for which an approximate expression can be calculated by the least square method described later.

  In S22, the period calculation device 1 uses the least squares method to calculate an approximate expression (the above-described formula) based on the relationship between the input composite acceleration of the predetermined number (n) of subjects and the pulse number of the predetermined number (n) of subjects. Equation 2) is obtained. Here, FIG. 9 is a diagram showing the relationship between the combined acceleration itotal-pulse rate characteristics acting on a predetermined number (n) of subjects. In the present embodiment, the provisional reference pulse rate can be expressed by the following approximate expression (similar to Expression 2 above).

Temporary reference pulse rate = a · itotal + b
= 0.0004 · itotal + 68.666
Next, the relationship between time and the pulse rate with respect to the reference period T (see S15 shown in FIG. 7) will be described with reference to FIG. FIG. 10 is a diagram illustrating the relationship between the heart rate and the pulse rate with respect to time when the process of the second embodiment is executed. As shown in FIG. 10, the pulse rate shows substantially the same value as the heart rate, and it can be seen that it does not deviate significantly from the heart rate.

  Specifically, the pulse rate is 160 in the vicinity of 500 s, but the pulse rate is 125 in the vicinity of 525 s thereafter, and the pulse rate decreases rapidly. This is because the original pulse wave was removed by a filter circuit or the like in the vicinity of 525 s, and the pulse rate was erroneously calculated.

  However, even after 500 s, the reference period T is appropriately corrected (see the above formulas 1 to 4) by the combined acceleration itotal and the like. For this reason, even if the pulse rate is erroneously calculated in the vicinity of 525 s, an appropriate pulse rate is calculated based on the reference period T that is appropriately corrected thereafter.

  Here, FIG. 11 is a diagram illustrating a relationship between the heart rate and the pulse rate with respect to time when the process of the second embodiment is not executed. As shown in FIG. 11, the pulse rate shows the same value as the heart rate at 0 to 485 s, but after that, the pulse rate may deviate greatly from the heart rate due to the influence of the filter circuit.

  For example, the period of the pulse rate 80 for the vicinity of 550 s may be twice or three times the period of the pulse rate 160 for the vicinity of 485 s. That is, the original pulse wave (for example, P4-5 shown in FIG. 13) is removed in the vicinity of 550 s due to the influence of the filter circuit or the like, and the period in the vicinity of 550 s is doubled or tripled in comparison with the previous period in the vicinity of 480 s. It may become. For this reason, if a cycle in the vicinity of 550 s is erroneously calculated as the reference cycle T, thereafter, the erroneously calculated reference cycle T is used as it is, and therefore the pulse rate continues to be erroneously calculated by the reference cycle T. In the present invention, as described with reference to FIG. 10, even if the reference period T is erroneously calculated, it is appropriately corrected to the optimum reference period T by the synthetic acceleration itotal and the like (see the above formulas 1 to 4). An appropriate pulse rate is calculated based on the optimum reference period T.

  Note that the cycle calculating device 1 calculates the pulse rate, but the heart rate can also be naturally calculated by the same processing.

  The period calculating device 1 corrects the reference period T by using the previous pulse rate corresponding to the reference period T and the combined acceleration itotal acting on the subject. Changes shown may be made. That is, the period calculation device 1 may be replaced with the acceleration sensor 80 and may be a pedometer that counts the number of steps of the subject or an analysis device that analyzes the gas component exhaled by the subject. This period calculation device 1 can correct the reference period T using the previous pulse rate corresponding to the reference period T and the number of steps of the subject counted by the pedometer or the gas component analyzed by the analysis device. it can.

  In addition, although the period calculation apparatus 1 presets the approximate expression (refer Formula 2) which is a composite acceleration-pulse rate characteristic, it is not limited to this, You may add the change shown next. Specifically, the cycle calculating device 1 sequentially stores the combined acceleration itotal calculated in S12 and the pulse rate value for the combined acceleration itotal.

  Then, the cycle calculating apparatus 1 uses almost all of the stored composite acceleration itotal and the pulse rate value on condition that the combined acceleration itotal and the pulse rate value are stored for a predetermined number of times in a predetermined period. The approximate expression is calculated, and the approximate expression set in advance is changed to the calculated approximate expression.

  In this case, the cycle calculation device 1 may calculate a more appropriate approximate expression (see Expression 2) by sequentially updating the approximate expression based on more synthetic acceleration itotal and the value of the pulse rate. it can. For this reason, the period calculation device 1 can more accurately calculate the provisional reference pulse rate for the synthetic acceleration itotal of the subject using the approximate expression, and as a result, the reference pulse rate (see Expression 3) and the reference period T (see Equation 4) can also be calculated more accurately.

(2) Reference cycle calculation process 2
The period calculation device 1 always calculates the reference period T using the combined acceleration itotal acting on the subject in the reference period calculation process 1 (see FIG. 7), but the reference period calculation process 2 acts on the subject. The difference is that the reference cycle T is not always calculated using the resultant acceleration itotal (see FIG. 7).

  FIG. 12 is a diagram illustrating the reference cycle calculation process 2 in the present embodiment. As shown in FIG. 12, in S21, the cycle calculation device 1 determines whether or not the reference cycle T belongs to a predetermined range. Examples of the predetermined range include a preset range and a range that is between the lower limit and the upper limit with respect to the cycle before the reference cycle T. Moreover, the period calculation apparatus 1 moves to the process of S22 when this determination is YES, and ends this process when it is NO.

  Since the processing from S22 to S26 is the same as the processing from S11 to S15 shown in FIG. 7, detailed description thereof is omitted.

  In this case, the cycle calculation device 1 corrects the reference cycle T using the acceleration value measured by the acceleration sensor 80 only when the reference cycle T does not belong to the predetermined range. To do. For this reason, since the cycle calculation device 1 does not execute the process of correcting the reference cycle T one by one, the cycle calculation device 1 can reduce the processing load on the cycle calculation device 1.

  Note that the program that operates in the period calculation device has the same function as the CPU 70. The program may be recorded on a recording medium. Examples of the recording medium include a hard disk, a flexible disk, a compact disk, an IC chip, and a cassette tape.

It is a schematic block diagram which shows the period calculation apparatus in 1st Embodiment. It is a figure which shows the period calculation method in 1st Embodiment. It is a figure which shows the period calculation process in 1st Embodiment (the 1). It is a figure which shows the period calculation process in 1st Embodiment (the 2). It is a schematic block diagram which shows the period calculation apparatus in 2nd Embodiment. It is a figure which shows the direction of the acceleration which acts on the test subject in 2nd Embodiment. It is a figure which shows the reference period calculation process 1 in 2nd Embodiment. It is a figure which shows the synthetic acceleration-pulse rate characteristic and calculation process in 2nd Embodiment. It is a figure which shows the relationship of the pulse rate with respect to the synthetic | combination acceleration in 2nd Embodiment. It is a figure which shows the relationship of the heart rate and the pulse rate with respect to time in 2nd Embodiment. It is a figure which shows the reference period calculation process 2 in 2nd Embodiment. It is a figure which shows the relationship between the heart rate and the pulse rate with respect to the time in the past. It is a figure which shows an example of the conventional pulse wave.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Period calculation apparatus, 10 ... Pulse wave sensor, 20 ... Detection part, 30 ... Band pass filter part, 40 ... Notification part, 50 ... RAM, 60 ... ROM, 70 ... CPU, 71 ... Peak interval specific | specification part, 72 ... Next peak interval specifying unit, 73 ... range setting unit, 74 ... period calculation unit, 77 ... correction unit, 80 ... acceleration sensor, 90 ... detection unit

Claims (8)

A cycle calculation device that is detachably attached to a subject,
A second sensor for measuring a subject's momentum correlated with a reference period measured by the first sensor;
A period calculation apparatus comprising: a correction unit that corrects the reference period measured by the first sensor using a value of momentum measured by the second sensor. The reference period is a period corresponding to the pulse rate or heart rate of the subject, and the momentum is a composite value of accelerations acting in three axis directions orthogonal to each other,
The correction unit includes an approximate expression calculated based on a relationship between a combined value of the accelerations of a large number of subjects and a pulse rate or a heart rate of the large numbers of subjects, and a combined value of the accelerations measured by the second sensor. The period calculation device according to claim 1, wherein the reference period measured by the first sensor is corrected by using the first and second sensors.   When the reference period measured by the first sensor does not fall within a predetermined range, the correction value corrects the reference period using a value of momentum measured by the second sensor, and 2. The reference period according to claim 1, wherein when the reference period measured by one sensor belongs to a predetermined range, the reference period is corrected using a value of momentum measured by the second sensor. Period calculation device. The first sensor measures the reference period which is an interval from one peak of the amplitude of the pulse wave of the subject to the next peak,
Range setting means for setting a specific range between a lower limit and an upper limit with respect to the reference period;
A period calculation unit that calculates the next period as a pulse wave period when a next period that is a next period with respect to the reference period measured by the first sensor belongs to the specific range; The period calculation device according to claim 1 or 3. A program that is detachably attached to a subject and that operates in a period calculation device that includes a second sensor that measures a subject's momentum correlated with a reference period measured by a first sensor,
Computer
A program that functions as a correction unit that corrects the reference period measured by the first sensor using the value of the momentum measured by the second sensor. The reference period is a period corresponding to the pulse rate or heart rate of the subject, and the momentum is a composite value of accelerations acting in three axis directions orthogonal to each other,
The correction unit includes an approximate expression calculated based on a relationship between a combined value of the accelerations of a large number of subjects and a pulse rate or a heart rate of the large numbers of subjects, and a combined value of the accelerations measured by the second sensor. The program according to claim 5, wherein the reference period measured by the first sensor is corrected by using.   When the reference period measured by the first sensor does not fall within a predetermined range, the correction value corrects the reference period using a value of momentum measured by the second sensor, and The said reference period is correct | amended using the value of the momentum measured by the said 2nd sensor, when the said reference period measured by 1 sensor belongs in the predetermined range. program. The first sensor measures the reference period which is an interval from one peak of the amplitude of the pulse wave of the subject to the next peak,
Range setting means for setting a specific range between a lower limit and an upper limit with respect to the reference period;
A period calculation unit that calculates the next period as a pulse wave period when a next period that is a next period with respect to the reference period measured by the first sensor belongs to the specific range; The program according to any one of claims 5 and 7.

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