JP6416722B2 - Step counting device, step counting method, and program - Google Patents

Description

  The present invention relates to a step count measuring apparatus, a step count measuring method, and a program for measuring the number of steps due to walking or running of a person.

  2. Description of the Related Art Conventionally, as a biological information measuring device for measuring human biological information, a step count measuring device for measuring the number of steps by walking or running of a worn person is known. Many of the step counting devices include three-axis acceleration sensors orthogonal to each other, detect the walking or running of a person wearing the acceleration sensor, and measure the number of steps by walking or running.

  For example, in Non-Patent Document 1, a piezoresistive three-axis acceleration sensor detects accelerations in the X-axis, Y-axis, and Z-axis directions, and a value obtained by combining the detected three-axis accelerations (three-axis The technique of counting the number of steps is considered that the fact that the combined value of the acceleration of (1) becomes higher than 1G after being lower than 1G is considered as the occurrence of walking. Non-Patent Document 2 discloses a system configuration diagram of a conventional step count measuring device that counts the number of steps based on a composite value of three axes and displays the counted number of steps on a display device.

"Triaxial acceleration sensor application note piezoresistive type triaxial acceleration sensor HAAM-326B pedometer", 1st edition, Hokuriku Electric Industry Co., Ltd., February 2007. “Low-Power Pedometer Using an MSP430TM MCU”, Dennis Lehman, Application Report, SLAA599, TEXAS INSTRUMENT, May 2013.

  It has been clarified by the inventors of the present application that the conventional step counting technique disclosed in Non-Patent Document 1 and Non-Patent Document 2 may erroneously detect human walking. Details will be described below.

  In the conventional general step count measurement technique disclosed in Non-Patent Document 1 and Non-Patent Document 2, a composite value of three axes is calculated by (Equation 1), and human walking and running are detected based on the calculated value. doing.

In equation (1), a _[n] is a composite value of triaxial acceleration, and ax _[n] , _{ay [n]} , and _{az [n]} are measured by a triaxial acceleration sensor. The measured values of acceleration in the directions of the nth (n is an integer of 1 or more) th axis from the start of step count measurement.

  As can be understood from the above equation (1), the combined value of the three-axis accelerations is always “0” or more. For this reason, even if the acceleration values in the respective axial directions are all “negative” values, the combined value of the triaxial accelerations is positive.

  In general, when a person walks or runs (hereinafter referred to as “walking motion”), the ground contact period in which one of the left foot and the right foot is in contact with the floor, and both the left foot and the right foot are not floating. There is a grounding period. In the ground contact period, due to the impact of one foot on the ground, a large force is instantaneously applied from the ground to the pedestrian's body vertically upward (vertically upward). Since the pedestrian's body is stagnant during the non-contact period, the force applied to the body generates only a gravitational acceleration that is vertically downward (vertically downward) with respect to the ground.

  For example, during a walking motion in which the wearer's body movement is large, a ground contact period and a non-ground contact period are alternately repeated, and acceleration vibration in a direction perpendicular to the ground occurs in the pedestrian's body. This time change of acceleration vibration is considered to be a sinusoidal periodic waveform. In other words, the composite value of the acceleration generated in the pedestrian's body becomes a characteristic that is convex during the ground contact period and concave during the non-ground contact period. Therefore, the number of steps can be counted by detecting the occurrence of the peak of the composite value of acceleration.

  On the other hand, at the time of a walking motion in which the wearer's movement is slow and the body motion is small, each one is clearly separated and a long contact period is generated continuously. In these contact periods, the composite value of the triaxial acceleration rises at the timing when one of the feet lands, and a peak that protrudes upward is generated. Thereafter, the composite value of the acceleration decreases. That is, in each contact period, the composite value of acceleration becomes a waveform having one large peak. Therefore, in this case as well, the number of steps can be counted by detecting the occurrence of the peak of the acceleration composite value.

  However, in the conventional step count measurement method, the number of steps in a walking operation in which each contact period is long and each contact time is clearly separated, such as a walking operation in which the wearer's movement is slow and the body motion is small. May occur.

FIG. 16 is a diagram illustrating a step count calculation result of a step count measuring apparatus including a conventional triaxial acceleration sensor.
FIG. 16 shows a characteristic 1001 of a composite value of triaxial acceleration during a walking motion in which the wearer's movement is slow and the body motion is small, and the number of steps 1002 measured based on the composite value.

  The step count 1002 shown in FIG. 16 is measured by the step count detection algorithm of the conventional step count measuring device described in “Step Count Measurement Method” and “Table 1” of Non-Patent Document 1. Specifically, the number of steps 1002 first detects that the combined value of the three axes is lower than the threshold “0.9G” as the first step, and then within a certain time (1 second) as the second step. If it is detected that the composite value of the three axes is higher than the threshold value “1.1G” and the difference from the previous composite value of the three axes is greater than or equal to the threshold value “0.2G”, the number of steps is counted. This is the result obtained by the step count detection algorithm that returns to the first step again when is established or not established.

  As shown in FIG. 16, in each contact period, the combined value of the triaxial accelerations increases at the timing when one of the feet lands, and a peak that protrudes upward occurs. The number of steps is counted by detecting the occurrence of this peak.

  However, in these contact periods, the composite value of the three-axis acceleration increases even at a timing when the ground is kicked out with one foot and then moves forward (the timing of kicking out) after a while. When a large increase in the composite value of acceleration occurs at the kicking-out timing, a peak in which the composite value is convex upward is generated as shown in FIG. When this peak satisfies the condition relating to the number of steps detection, as indicated by reference numeral 1003, the number of steps is erroneously detected.

  If there is such an erroneous detection of the number of steps, an error occurs between the actual number of steps and the detected number of steps, and the error is accumulated, so that the accuracy as the step counting device is significantly lowered. As a result, wrong information is presented to the wearer of the pedometer, and there is a risk that the quality of life of the wearer who is keeping good health will be significantly impaired.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce the occurrence of erroneous detection of the number of steps due to walking or running of a person.

  The step count measuring device (1, 2, 3, 4) according to the present invention obtains measured values of acceleration of the respective measurement axes (xa, ya, za) measured by the acceleration sensor (101) having a plurality of measurement axes. A composite value calculation unit (12) that combines and calculates a composite value, detects a change in the composite value that satisfies a predetermined condition, and calculates the number of steps by walking or running by the wearer of the acceleration sensor based on the number of detections. A step number calculating unit (14), and the step number calculating unit detects a variation of the composite value that satisfies the predetermined condition and detects a variation of the composite value that occurs within the predetermined period (Tx) after detecting the variation of the composite value that satisfies the predetermined condition. It is characterized by not counting as the number of steps.

  The above step count measuring device (1, 2, 3, 4) further includes a walking pitch estimation unit (13) that estimates the walking pitch of the walking motion by the wearer based on the composite value, and the step calculation unit includes the walking pitch The length of the predetermined period may be changed based on the walking pitch estimated by the estimation unit.

  In the step count measuring device (1, 2, 3, 4), the walking pitch estimation unit estimates the walking pitch based on the magnitude of variation from the average value of the synthesized values, and the step count calculation unit calculates the walking pitch. You may set so that the said predetermined period may become short according to increase.

  The step counting device (2, 4) further includes a moving speed calculating unit (17) for calculating the moving speed of the wearer, and the step calculating unit has a predetermined speed when the moving speed does not exceed the threshold value. The variation in the composite value that satisfies the condition is counted as the number of steps, and the variation in the composite value that satisfies the predetermined condition is not counted as the number of steps when the moving speed calculated by the moving speed calculation unit exceeds the threshold value. You may do it.

  In the step counting device (4), a sensor unit (10) having the acceleration sensor, an output unit (103) for outputting a measured value of acceleration for each measurement axis measured by the acceleration sensor, and an output from the output unit A storage unit (11) for storing the measured acceleration value for each measurement axis, and the sensor unit and the output unit are formed in the first terminal (5), and the storage unit, the combined value calculation unit, and the walking The pitch estimation unit and the step count calculation unit may be formed in a second terminal (6) different from the first terminal.

  In the above description, as an example, constituent elements on the drawing corresponding to the constituent elements of the invention are represented by reference numerals with parentheses.

  According to the present invention, it is possible to reduce the occurrence of erroneous detection of the number of steps due to walking or running of a person.

FIG. 1 is a diagram showing a configuration of a step count measuring apparatus according to the first embodiment. FIG. 2 is a diagram showing an outline of the step count measurement process by the step count measuring apparatus according to the first embodiment. FIG. 3 is a diagram showing the relationship between the variance of the synthesized value of the acceleration and the walking pitch in the walking motion. FIG. 4 is a diagram illustrating an example of a method for determining a limit period in the step count measuring apparatus according to the first embodiment. FIG. 5 is a diagram showing the step count measurement result of the step count measuring apparatus according to the first embodiment. FIG. 6 is a diagram showing a configuration of the step count measuring apparatus according to the second embodiment. FIG. 7 is a diagram showing a step count measurement result by the step count measuring apparatus according to the first embodiment. FIG. 8 is a diagram showing a configuration of the step count measuring apparatus according to the third embodiment. FIG. 9 is a diagram showing an outline of the step count measurement process by the step count measuring apparatus according to the third embodiment. FIG. 10 is a diagram illustrating an example of an internal configuration of an inclination calculation unit in the step count measuring apparatus according to the third embodiment. FIG. 11 is a diagram for explaining a process of calculating the inclination of each measurement axis of the acceleration sensor with respect to the gravitational acceleration. FIG. 12 is a diagram illustrating a step count measurement result of a step count measuring apparatus including a conventional triaxial acceleration sensor. FIG. 13 is a diagram illustrating a step count measurement result of the step count measuring apparatus according to the third embodiment. FIG. 14 is a diagram illustrating a configuration of a step count measuring apparatus according to the fourth embodiment. FIG. 15 is a diagram illustrating a specific implementation example of the step count measuring apparatus according to the fourth embodiment. FIG. 16 is a diagram illustrating a configuration of a step count measuring apparatus according to the fourth embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< Embodiment 1 >>
<Configuration of Step Counting Apparatus 1 According to Embodiment 1>
FIG. 1 is a diagram showing a configuration of a step count measuring apparatus according to the first embodiment.
A step count measuring apparatus 1 shown in FIG. 1 is mounted on a living body represented by a person, for example, and measures the number of steps by walking or running of the mounted living body (wearer) based on the detection result of acceleration by an acceleration sensor. It is. The step counting device 1 has a function of detecting an appropriate number of steps according to the body motion scale of the wearer's walking motion when calculating the number of steps based on the acceleration detection result.
Hereinafter, a specific configuration of the step count measuring apparatus 1 will be described.

  As shown in FIG. 1, the step count measuring device 1 includes a sensor unit 10, a storage unit 11, a composite value calculation unit 12, a walking pitch estimation unit 13, a step count calculation unit 14, and a display unit 15.

  The sensor unit 10 is a functional unit that reads biological information generated by the movement of the wearer's body and gravity. The sensor unit 10 includes, for example, an acceleration sensor 101 having a plurality of measurement axes and an A / D converter 102.

  The acceleration sensor 101 is a triaxial acceleration sensor having three measurement axes, for example, an X axis, a Y axis, and a Z axis, and measures the acceleration of each measurement axis of the X axis, the Y axis, and the Z axis.

  The A / D converter 102 converts each analog axis measurement value measured by the acceleration sensor 101 into a digital signal at a predetermined conversion cycle, and measures an acceleration measurement value (X-axis acceleration) ax in the X-axis direction. [N], Y axis direction acceleration measurement value (Y axis acceleration) ay [n], and Z axis direction acceleration measurement value (Z axis acceleration) az [n]. Here, as described above, n is an integer equal to or greater than 1, and represents the order after the measurement is started (for example, the order in which the A / D conversion process is performed).

  The storage unit 11 is a functional unit for storing measured values of acceleration of each axis output from the sensor unit 10. Examples of the storage unit 11 include a rewritable nonvolatile memory such as a flash memory, a RAM (Random Access Memory), and the like.

  The composite value calculation unit 12, the walking pitch estimation unit 13, and the step count calculation unit 14 are realized by program processing executed by a program processing device such as an MCU (Memory Control Unit), for example.

  The composite value calculation unit 12 calculates the composite value by combining the acceleration measurement values of the respective measurement axes stored in the storage unit 11.

The walking pitch estimation unit 13 is a functional unit that estimates the wearer's walking pitch as an index for evaluating the wearer's body movement scale during walking or running.
Here, the walking pitch is the number of steps per unit time (for example, one minute).

  The number-of-steps calculation unit 14 is a functional unit for calculating the number of steps due to walking or running by the wearer based on the combined acceleration value calculated by the combined value calculation unit 12. Specifically, the step count calculation unit 14 detects a change in the composite value that satisfies the step count detection condition, and calculates the step count based on the number of detections.

  Here, the step count detection condition is a condition for determining the presence or absence of walking or running based on the variation of the combined value of acceleration with time. Details of the step count detection condition will be described later.

  Also, the step count calculation unit 14 does not count as a step count (hereinafter referred to as “limit period Tx”) even when the change in the composite value satisfies the step count detection condition during the step count calculation process. It has). The limit period Tx is set immediately after the step count calculation unit 14 detects a change in the composite value that satisfies the step count detection condition (for example, immediately after counting the number of steps).

  In addition, the number-of-steps calculation unit 14 sets the length of the limit period Tx based on the walking pitch estimation result by the walking pitch estimation unit 13.

  The display unit 15 is a functional unit for visually providing information on the number of steps calculated by the number-of-steps calculation unit 14 to users including the wearer. Examples of the display unit 15 include display devices such as a liquid crystal display and an organic EL display.

<Step Counting Process by Step Counting Apparatus 1 According to Embodiment 1>
Next, the step count measurement process by the step count measuring apparatus 1 according to the first embodiment will be described.
FIG. 2 is a diagram showing an outline of the step count measurement process by the step count measuring apparatus according to the first embodiment.

  First, the step count measuring apparatus 1 synthesizes the measured values of triaxial acceleration by the acceleration sensor 101 stored in the storage unit 11 and calculates a combined value of acceleration (S1). Next, the step count measuring apparatus 1 estimates the walking pitch by the wearer based on the combined value of the accelerations calculated in step S1 (S2). Next, the step count measuring apparatus 1 determines the length of the limit period Tx when counting the number of steps based on the walking pitch estimated in step S2 (S3). Thereafter, the step counting device 1 detects a change in the combined value of accelerations that satisfies the step detection condition according to the limit period Tx determined in step S3, and based on the number of detections, calculates the number of steps due to walking or running by the wearer of the acceleration sensor. Calculate (S4).

  Thereafter, the information on the calculated number of steps is displayed on the display unit 15. Note that the information on the number of steps is not only displayed on the display unit 15 but may be stored in the storage unit 11 or may be transmitted to an external device wirelessly or by wire.

  Next, each step in the step count measurement process shown in FIG. 2 will be described in detail.

(1) Step S1 (calculation process of acceleration composite value a _[n] )
In step S _< b _> 1, the composite value calculation unit 12 is based on the X-axis acceleration a _{x [n]} , the Y-axis acceleration a _{y [n]} , and the Z-axis acceleration a _{z [n]} stored in the storage unit 11. Thus, a composite value a _[n] of the triaxial acceleration is calculated. Specifically, the composite value calculation unit 12 calculates a composite value a _[n] of triaxial acceleration by solving the above-described equation (1).

(2) Step S2 (walking pitch estimation process)
In step S2, the walking pitch estimation unit 13 estimates the wearer's walking pitch.
According to the study by the present inventor, it has been found that there is a correlation between the statistic of the walking pitch and the synthesized value a _[n] of acceleration.

FIG. 3 is a diagram illustrating a relationship between a statistic of a composite value of acceleration in a walking motion and a walking pitch.
FIG. 3 shows the walking pitch (number of steps per minute) during walking or running by 11 subjects and the average value of the combined acceleration values, which is one of the statistics of the combined acceleration values in walking motion. An actual measurement result of the variance S _[n] ² representing the magnitude of the variation is shown.
In FIG. 3, the vertical axis represents the variance [G ² ] of the synthesized value of acceleration, and the horizontal axis represents the walking pitch [spm: steps per minute].

  As can be understood from FIG. 3, the measurement results are scattered in the upward direction, and there is a correlation between the walking pitch and the variance. For example, the variance decreases when walking with a low walking pitch, and increases when traveling with a high walking pitch. That is, the higher the walking pitch, the higher the variance. Therefore, if the variance of the composite value of acceleration is obtained, the walking pitch (body movement scale) of the wearer can be estimated.

The variance S _[n] ^{2 with} respect to the composite value of the nth acceleration can be expressed by equation (2).
Here, as an example, the number of samples of the composite value when calculating the variance is “25”, and the composite value of the 25 most recent time series accelerations related to the composite value of the nth measured acceleration is used.

  In the equation (2), Av [n] is an average value of the combined acceleration values and can be represented by the equation (3).

In step S2, the walking pitch estimator 13 calculates the variance S _[n] ² of the composite value of the nth acceleration by calculating the above equations (2) and (3), and estimates the walking pitch. .

(3) Step S3 (determination process of the limit period Tx)
In step S3, the step count calculation unit 14 determines the length of the limit period Tx.
Specifically, the step count calculation unit 14 sets the limit period Tx to be shorter as the walking pitch increases. More specifically, the step count calculation unit 14 determines the limit period Tx based on the variance S _[n] ² of the composite value of the nth acceleration calculated by the walking pitch estimation unit 13.

FIG. 4 is a diagram illustrating an example of a method for determining the limit period Tx.
As shown in FIG. 4, the step count calculation unit 14 determines different limit periods Tx according to the range of the variance S _[n] ² . For example, when the variance S _[n] ² is less than 0.26, the limit period Tx is 320 ms, and when the variance S _[n] ² is 0.26 or more and less than 0.6, the limit period Tx is 240 ms. When the variance S _[n] ² is 0.6 or more, the limit period Tx is set to 120 ms.

As described above, the step count calculation unit 14 sets the limit period Tx to be shorter as the variance S _[n] ² is larger. According to this, for example, the restriction period Tx is set to be long in the case of a walking action with a small body movement such as walking, and the restriction period Tx is set to be short in the case of a walking action with a large body movement like running. Is done.

In the above example, variance is used as an index representing the magnitude of variation from the average value of the combined acceleration values. However, standard deviation may be used instead of variance. The standard deviation S can be calculated by taking the square root of the variance S ² as shown in equation (4).

(5) Step S4 (step count calculation process)
In step S4, the number-of-steps calculation unit 14 counts the number of times that the variation with time of the combined acceleration value a _[n] calculated in step S1 satisfies the number of steps detection condition according to the limit period Tx set in step S3. The number of times is calculated as the number of steps.

Here, as an example, the step count calculation unit 14 employs the same step count detection condition as that of the conventional step count measuring apparatus shown in FIG. In other words, the step count calculation unit 14 determines that the combined acceleration value a _[n] within a certain time (for example, 1 second) after the combined acceleration value a _[n] becomes lower than the first threshold (for example, 0.9 G) _. Is greater than the second threshold (eg, 1.1 G) and the difference from the previous acceleration composite value a _[n] is greater than or _equal to the third threshold (eg, 0.2 G) as a step count detection condition.

When the combined acceleration value a _[n] satisfies the above-described step count detection condition, the step count calculation unit 14 determines that there has been a walk or a run and counts up the number of steps. On the other hand, when the combined value a _{[n] of} acceleration does not satisfy the above step detection condition, the step count is not counted up.

In addition, the step count calculation unit 14 does not count the next change in the composite value detected until the limit period Tx elapses after the change in the composite value satisfying the step count detection condition is detected. That is, even if the change in the acceleration acceleration value a _[n] satisfies the above step detection condition within the limit period Tx immediately after detection of walking or running, it is not determined that walking or running has occurred. , Don't count up steps.

<Effects of the step counting device 1 according to Embodiment 1>
FIG. 5 is a diagram showing the step count measurement result of the step count measuring apparatus 1 according to the first embodiment.
In FIG. 5, by using the acceleration data of each measurement axis similar to the conventional step counting device shown in FIG. 16, the characteristic 2001 of the acceleration synthesized value a _[n] calculated by the step counting device 1; A step count 2002 calculated by the step count measuring apparatus 1 based on the combined acceleration value a _[n] is shown. As a comparative example, a step count 1002 calculated by the conventional step count measuring apparatus shown in FIG. 16 is also shown.

As described above, in the step count measuring apparatus 1, a combination of accelerations satisfying the step count detection condition is detected until a limit period Tx elapses after a change in the synthesized value a _[n] of the acceleration satisfying the step count detection condition is detected. Even if the next fluctuation of the value a _[n] occurs, it is not determined that there was walking or running. As a result, as shown in FIG. 5, the step counting device 1 does not count the number of steps associated with the increase in the composite value a _[n] of acceleration at the time of kicking that occurs during the contact period from time t4 to t5. It is possible to prevent erroneous detection of the number of steps that has occurred in the step counting device.

As described above, according to the step count measuring apparatus 1 according to the first embodiment, since the limit period Tx for masking the detection of the step count is provided after the change in the synthesized value a _[n] of the acceleration satisfying the step count detection condition is provided, for example, Further, it is possible to prevent erroneous detection of the number of steps due to an increase in the composite value of acceleration generated at the timing of kicking one leg in a walking motion with a small body motion.

  Thereby, compared with the conventional step counting device, it is possible to reduce the occurrence of erroneous detection of the step number, and it is possible to present more accurate step number information to the wearer of the step counting device.

  Moreover, according to the step count measuring apparatus 1, since the restriction | limiting period Tx is changed according to a wearer's walking pitch, the suitable step count measurement corresponding to various walking motion is realizable.

  For example, in a walking action with a low walking pitch (small body movement), if a change in the combined value of accelerations that satisfies the step count detection condition occurs 280 ms after detecting one walk, as shown in FIG. If the limit period Tx is set to 320 ms, the fluctuation can be prevented from being counted as the number of steps.

  On the other hand, a walking action with a high walking pitch (large body movement) such as running has a shorter ground contact period than a walking action with a low pitch, so the limit period Tx is set to the same value as the above walking time. If set, there is a possibility that a situation in which a walk that should be detected cannot be detected occurs.

Therefore, as in the step counting device 1 according to the first embodiment, by setting the restriction period Tx to be shorter as the walking pitch is higher, it is possible to avoid a situation in which the originally detected walking or running cannot be detected. be able to.
That is, according to the step count measuring apparatus 1, when the body movement is small as during walking, the restriction period Tx is set to be long, and when the body movement is large as during running, the restriction period Tx is set to be short. Therefore, it is possible to realize appropriate number of steps detection corresponding to various walking motions.

<< Embodiment 2 >>
FIG. 6 is a diagram showing a configuration of the step count measuring apparatus according to the second embodiment.
The step count measuring apparatus 2 according to the second embodiment is different from the step count measuring apparatus 1 according to the first embodiment in that it has a function of limiting the detection of the number of steps based on the moving speed of the wearer. This is the same as the step count measuring apparatus 1 according to the first embodiment.

  Specifically, the step count measuring device 2 further includes a position information acquisition unit 16 and a moving speed calculation unit 17 in addition to the functional units constituting the step count measuring device 1 according to the first embodiment. The step number detecting unit 18 is provided.

  In the step count measuring apparatus 2 according to the second embodiment, the same components as those in the step count measuring apparatus 1 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The position information acquisition unit 16 is a functional unit for acquiring the wearer's position information.

  Here, the position information is information related to a position provided by a wireless communication system such as a GPS or a mobile phone. The position information includes, for example, latitude information and longitude information of a place where a wearer exists discontinuously from an artificial satellite.

  For example, the position information acquisition unit 16 includes an antenna, a communication circuit, and the like for receiving data transmitted from a wireless communication system such as a GPS or a mobile phone.

The movement speed calculation unit 17 is a functional unit that calculates the movement speed of the wearer based on the position information acquired by the position information acquisition unit 16.
Specifically, the movement speed calculation unit 17 calculates the movement speed from the time change of the latitude and longitude information acquired by the position information acquisition unit 16. More specifically, the moving speed calculation unit 17 calculates an angle formed by two straight lines connecting two points on the spherical surface from the center of the sphere (Earth), and calculates the moving speed based on the angle. To do.
Hereinafter, a method for calculating the moving speed by the moving speed calculator 17 will be described in detail.

  First, the moving speed calculation unit 17 sets the latitude of the wearer's point measured nth to δ [n], the longitude is λ [n], and the latitude of the wearer's point measured n + 1 is δ [n + 1]. ] When longitude is λ [n + 1], an angle d formed by two straight lines connecting two points from the center of the earth is calculated.

Here, the angle d can be expressed by Expression (5) from the spherical trigonometric formula.
In equation (5), longitude is positive in east longitude, negative in west longitude, and latitude is positive in north latitude and negative in south latitude. The unit of the angle d is radians.

  Here, what we want to know is the angle d, but the walking distance is very small with respect to the size of the earth, and when the angle is small, the cosine hardly changes. May be affected. Therefore, Equation (5) is rewritten to Equation (6) in which the cosine on the left side is converted to sine.

  Here, the above equation (6) is obtained by modifying the equation (5) using the half-width / double-angle formula and does not use any approximation, and therefore is equivalent to the equation (5). Therefore, it is possible to expand the adaptation condition to walking without changing the principle.

Therefore, the moving speed calculation unit 17 first calculates sin ² (d / 2) from the equation (6). Next, the moving speed calculation unit 17 calculates an angle d by calculating an inverse function (arcsin) of the sine with respect to the square root of sin ² (d / 2) and then doubling the value.

Next, the moving speed calculation unit 17 calculates the distance R between the two points.
Since the length of the fan-shaped arc is expressed by the product of the central angle and the radius, the distance R between the two points can be obtained by multiplying the angle d by the average radius of the earth (= 6370 km). Specifically, the moving speed calculation unit 17 calculates a distance R [km] between two points by solving the following equation (7).

  In Expression (7), the distance R is a moving distance per sampling interval for acquiring position information. Therefore, if the sampling interval is T [seconds], the moving speed v [km / h] can be calculated. Specifically, the movement speed calculation unit 17 calculates the wearer's movement speed v [km / h] by solving Equation (8).

  The number-of-steps calculation unit 18 determines the validity / invalidity of the number of steps detection based on the wearer's movement speed v calculated by the movement speed calculation unit 17.

FIG. 7 is a diagram illustrating an example of a method for determining whether to detect the number of steps based on the moving speed v.
The step count calculation unit 18 determines whether the step count detection is valid / invalid by determining whether or not the moving speed v is greater than a threshold value.

  For example, as shown in FIG. 7, when the moving speed v is less than the threshold value vt = 35 km / h, the detection of the number of steps is validated, and the change in the combined value of the accelerations satisfying the number of steps detection condition in the period other than the limit period Tx. When it is detected, it is counted as the number of steps. On the other hand, when the moving speed v is greater than or equal to the threshold value vt = 35 km / h, the step count detection is invalidated, and even if a change in the combined value of accelerations that satisfies the step count detection condition is detected, the step count is not counted.

  As described above, according to the step count measuring apparatus 2 according to the second embodiment, the validity / invalidity of the step count detection can be switched according to the wearer's moving speed. If the value is far from running (for example, 35 km / h or more) and it is assumed that the wearer is moving on a vehicle such as an automobile, bicycle, or train, the change in the combined value of acceleration that satisfies the step detection condition It can be set so that the number of steps is not counted even if this occurs. Thereby, the occurrence of erroneous detection of the number of steps can be further reduced.

<< Embodiment 3 >>
FIG. 8 is a diagram showing a configuration of the step count measuring apparatus according to the third embodiment.
The step count measuring apparatus 3 according to the third embodiment corrects a composite value of acceleration in consideration of acceleration vibration in a direction perpendicular to the ground during the wearer's walking motion, and detects the number of steps based on the corrected composite value. The steps are different from the step count measuring apparatus 1 according to the first embodiment, and the other points are the same as the step count measuring apparatus 1 according to the first embodiment.

  Specifically, the step count measuring device 3 further includes an inclination calculation unit 20, a vibration direction determination unit 21, and a composite value correction unit 22. Similar to the walking pitch estimation unit 13 and the like, the inclination calculation unit 20, the vibration direction determination unit 21, and the composite value correction unit 22 are realized by program processing executed by a program processing device such as an MCU.

  The inclination calculation unit 20 is a functional unit for detecting an attachment angle of the acceleration sensor 101 when the step count measuring device is worn on a living body. Specifically, the inclination calculation unit 20 calculates an inclination (inclination) with respect to a direction (vertical direction) perpendicular to the ground of the acceleration sensor 101 based on the measurement value of the acceleration of each measurement axis stored in the storage unit 11. calculate.

  The vibration direction determination unit 21 is a functional unit that determines the direction (phase) of vibration in the vertical direction of the wearer wearing the acceleration sensor 101 based on the inclination calculated by the inclination calculation unit 20.

  The composite value correction unit 22 is a functional unit for correcting the composite value of acceleration according to the vertical movement of the wearer of the acceleration sensor 101. Specifically, the composite value correction unit 22 corrects the composite value calculated by the composite value calculation unit 12 based on the vibration direction of the wearer in the vertical direction determined by the vibration direction determination unit 21.

  The walking pitch estimation unit 23 and the step count calculation unit 24 use the composite value of acceleration corrected by the composite value correction unit 22 in place of the composite value of acceleration calculated by the composite value calculation unit 12, and the first embodiment. The same processing as the walking pitch estimation unit 13 and the step count calculation unit 14 is performed.

  Next, step count measurement processing by the step count measuring apparatus 3 according to Embodiment 3 will be described.

FIG. 9 is a diagram showing an outline of the step count measurement process by the step count measuring apparatus according to the third embodiment.
First, similarly to the step count measuring apparatus 1 according to the first embodiment, the step count measuring apparatus 3 synthesizes the measurement values of the three axes of acceleration by the acceleration sensor 101 stored in the storage unit 11, and obtains the synthesized value of the acceleration. Calculate (S1). Next, the step count measuring device 3 calculates the inclination of the acceleration sensor 101 with respect to the vertical direction based on the measurement value of the acceleration of each measurement axis (S6).

  Next, the step counting device 3 determines the direction of vibration in the vertical direction of the wearer of the acceleration sensor 101 based on the inclination calculated in step S6 (S7). Next, the step count measuring device 3 corrects the synthesized value of the acceleration of each measurement axis calculated in step S1 based on the vibration direction determined in step S7 (S8).

  After that, the step counting device 3 determines the walking pitch estimation process (S2) and the limit period Tx based on the corrected composite value calculated in step S8, similarly to the step counting device 1 according to the first embodiment. Processing (S3) and step count calculation processing (S4) are executed.

Next, each step in the step count measurement process shown in FIG. 9 will be described in detail.
Here, step S6, step S7, and step S8, which are processing steps unique to the step count measuring apparatus 3 according to the third embodiment, will be described in detail, and the same processing steps as the step count measuring apparatus 1 according to the first embodiment will be described. A description of S2 to S4 is omitted.

(1) Step S6 (inclination calculation process)
In step S6, the inclination calculation unit 20 calculates the inclination of the acceleration sensor 101 with respect to the vertical direction.
Specifically, the inclination calculating unit 20 first performs a process of extracting a vector amount based on the gravitational acceleration by removing a high-frequency component from the combined value a [n] of the triaxial acceleration. Next, the inclination calculation unit 20 performs a process of calculating the inclination of each measurement axis of the acceleration sensor 101 with respect to the gravitational acceleration based on the extracted vector amount based on the gravitational acceleration. Hereinafter, each of the above processes will be specifically described.

FIG. 10 is a diagram illustrating an example of an internal configuration of the inclination calculation unit 20.
As shown in FIG. 10, the inclination calculation unit 20 includes a low-pass filter 201 and an angle calculation unit 202.

The low-pass filter 201 is a function for realizing the process of extracting the vector quantity based on the gravitational acceleration described above, and the X-axis acceleration a _{x [n]} and the Y-axis acceleration a _{y [ n]} , the Z-axis acceleration a _{z [n]} , and the combined value a _{[n] of the} three-axis acceleration are subjected to band limiting processing.
In the present embodiment, the low-pass filter 201 will be described using a filter that performs the band limiting process represented by Expression (9) as an example.

In equation (9), β _[n] represents the input of the low-pass filter 201, and any of the above-described a _{x [n]} , a _{y [n]} , a _{z [n]} , and a _[n] is substituted. The β ′ _[n] represents the output of the low-pass filter 201. Further, h is an arbitrary filter coefficient and is a value in the range of 0 to 1. The closer h is to “1”, the stronger the band limiting effect of the low-pass filter 201 and the wider the frequency band to be removed.

  In equation (9), for example, when h = 0.9, it means that 90% of the acceleration measured in the previous measurement cycle is taken over by the acceleration measured in the next measurement cycle. By setting the filter coefficient h to about 0.9 (for example, h = 0.85 to 0.95), only the occurrence of sharp irregularities can be removed by means of continuation of the previous measurement value.

  As described above, when acceleration data is input to the low-pass filter 201, high-frequency components included in the acceleration data, that is, sharp irregularities are removed, so that a change in acceleration (acceleration characteristics) with time elapses into a sine wave. Close shape.

In the process for extracting the vector quantity based on the gravitational acceleration in the above-described step S6, the high frequency component is removed by inputting the acceleration composite value a _[n] to the low-pass filter 201, and the synthesis includes only the low frequency component. The value a ′ _[n] is calculated. Thereby, the acceleration component due to the body movement of the wearer of the acceleration sensor 101 is removed, and the vector amount a ′ _[n] in which the gravitational acceleration component is dominant can be obtained. Hereinafter, the vector quantity _a'[n], referred to as vector quantity _a'[n] based on the gravitational acceleration.

By referring to the vector quantity a ′ _[n] based on the gravitational acceleration, it is possible to determine the direction of the gravitational acceleration. Further, according to the low-pass filter 201 represented by the equation (9), acceleration data measured in the next measurement cycle by the two items “(1-h) β [n]” on the right side in the equation (9). Is updated (in the case of h = 0.9, 10% of the acceleration data of the next measurement cycle), it is possible to follow a rough change in the posture of the wearer.

In general, an acceleration sensor measures not the gravitational acceleration itself but the reaction force as a reaction, and thus the vector amount a ′ _[n] based on the gravitational acceleration represents the reaction of the gravitational acceleration.

  The angle calculation unit 202 is a functional unit for realizing the process of calculating the inclination of each measurement axis of the acceleration sensor 101 with respect to the gravitational acceleration, and calculates the inclination of each measurement axis of the acceleration sensor 101 with respect to the gravitational acceleration.

FIG. 11 is a diagram for explaining a process of calculating the inclination of each measurement axis of the acceleration sensor 101 with respect to the gravitational acceleration.
In FIG. 11, the Z axis is an axis perpendicular to the ground (vertical direction). The X axis and the Y axis are orthogonal to each other and also orthogonal to the Z axis. Further, the xa axis, the ya axis, and the za axis are measurement axes of the acceleration sensor 101.

  The directions of the measurement axes of the acceleration sensor 101, the xa axis, the ya axis, and the za axis, depend on the angle at which the acceleration sensor 101 is attached to the wearer's body, and therefore are not necessarily the xa axis, ya axis, and za axis. Neither is an axis perpendicular to the ground. Therefore, the angle calculation unit 202 determines the inclination (deviation) of the xa axis, the ya axis, and the za axis with respect to the Z axis perpendicular to the ground as an angle between the reaction of gravity acceleration and each measurement axis of the acceleration sensor 101. Calculate as

Specifically, as illustrated in FIG. 11, the angle calculation unit 202 performs the acceleration a ′ _{x [n]} of the xa axis after passing through the low-pass filter 201 with respect to the vector amount a ′ _[n] based on the gravitational acceleration. Information on the angle between the ya-axis acceleration a ′ _{y [n]} and the za-axis acceleration a ′ _{z [n]} is calculated. More specifically, by solving the following equations (10), (11), and (12), information on the angles of the xa axis, the ya axis, and the za axis with respect to the vector quantity a ′ _[n] based on the gravitational acceleration. sin θx [n], sin θy [n], and sin θz [n] are calculated.

(2) Step S7 (Vertical vibration direction determination process)
In step S7, the vibration direction determination unit 21 determines the direction of vibration in the vertical direction of the wearer of the acceleration sensor 101 based on the inclination calculated in step S6.

  Specifically, the vibration direction determination unit 21 first performs a process of determining the closest vertical axis to the vertical axis (Z axis) among the measurement axes xa, ya, and za of the acceleration sensor 101. Specifically, the vibration direction determination unit 14 uses the angle information sin θx [n], sin θy [n], sin θz [n] calculated by the angle calculation unit 202 based on the above formulas (10) to (12). Each measurement is compared, and the measurement axis having the smallest information on the angle is defined as the most vertical axis.

  For example, when | sin θx [n] | ≦ | sin θy [n] | and | sin θx [n] | ≦ | sin θz [n] |, the xa axis of the acceleration sensor 101 becomes the most vertical axis. When | sin θy [n] | ≦ | sin θx [n] | and | sin θy [n] | ≦ | sin θz [n] |, the ya axis of the acceleration sensor 101 is the most vertical axis. Also, when | sin θz [n] | ≦ | sin θx [n] | and | sin θz [n] | ≦ | sin θy [n] |, the za axis of the acceleration sensor 101 is the most vertical axis.

  Next, the vibration direction determination unit 21 performs a process of determining the direction of the most vertical axis with respect to the ground. Specifically, from the sign of the acceleration value of the most vertical axis after passing through the low-pass filter 201, the vibration direction determination unit 21 determines whether the most vertical axis is upward (vertically upward) or downward ( Vertically downward).

For example, when the xa axis is the most vertical axis and the acceleration a ′ _{x [n]} ≧ 0 after passing through the low-pass filter 201, the most vertical axis xa axis is vertically upward. If a ′ _{x [n]} <0, it is determined that the xa axis that is the most vertical axis is vertically downward. For example, when the ya axis is the most vertical axis, if the acceleration a ′ _{y [n]} ≧ 0 after passing through the low-pass filter 201, the ya axis that is the most vertical axis is vertically upward. If it is determined that there is a ′ _{y [n]} <0, it is determined that the ya axis that is the most vertical axis is vertically downward. Further, for example, when the za axis is the most vertical axis, if the acceleration a ′ _{z [n]} ≧ 0 after passing through the low-pass filter 201, the za axis that is the most vertical axis is vertically upward. If it is determined that there is a ′ _{z [n]} <0, it is determined that the za axis which is the most vertical axis is vertically downward.

Next, the vibration direction determination unit 21 performs a process of determining the vibration direction of the wearer of the acceleration sensor 101 in the vertical direction. Specifically, the vibration direction determination unit 21 determines the phase of the composite value a _[n] with respect to the most vertical axis based on the measured value of the acceleration of the most vertical axis and the direction of the most vertical axis determined in the above processing. To do.

For example, when the xa axis that is the most vertical axis is vertically upward, if the acceleration a _{x [n]} ≧ 0 before passing through the low-pass filter 201, the combined value a _[n] is relative to the most vertical axis. It is determined that the vibration in the vertical direction of the wearer of the acceleration sensor 101 is vertically upward. On the other hand, if the acceleration a _{x [n]} <0 of the xa axis, the combined value a _[n] is in an opposite phase to the most vertical axis, and the vertical vibration of the wearer of the acceleration sensor 101 is vertically downward. Is determined.

Further, for example, when the ya axis that is the most vertical axis is vertically upward, if the acceleration a _{y [n]} ≧ 0 of the ya axis before passing through the low-pass filter 201, the combined value a _[n] is the most vertical axis. It is determined that the vibration in the vertical direction of the wearer of the acceleration sensor 101 is vertically upward. On the other hand, if the acceleration a _{y [n]} <0 of the xa axis, the combined value a _[n] is in an opposite phase with respect to the most vertical axis, and the vertical vibration of the wearer of the acceleration sensor 101 is vertically downward. Is determined.

Further, for example, when the za axis that is the most vertical axis is vertically upward, and the acceleration a _{z [n]} ≧ 0 of the za axis before passing through the low-pass filter 201, the combined value a _[n] is the most vertical axis. It is determined that the vibration in the vertical direction of the wearer of the acceleration sensor 101 is vertically upward. On the other hand, if the acceleration a _{z [n]} <0 of the za axis, the composite value a _[n] is in an opposite phase with respect to the most vertical axis, and the vertical vibration of the wearer of the acceleration sensor 101 is vertically downward. Is determined.

(3) Step S8 (Acceleration value correction processing)
In step S8, the composite value correction unit 22 corrects the composite value of the acceleration of each measurement axis based on the wearer's vertical vibration direction determined in step S7.
Specifically, when it is determined in step S7 that the vibration in the wearer's vertical direction is vertically upward, the sign of the composite value a _[n] calculated by the composite value calculator 12 is “positive”. When the wearer's vertical vibration is determined to be vertically downward, the sign of the composite value a _[n] calculated by the composite value calculation unit 12 is set to “negative”.

That is, the corrected composite value A _[n] of acceleration is expressed by equation (13) when it is determined that the wearer's vertical vibration is vertically upward, and the wearer's vertical vibration is Is determined to be vertically downward, it is expressed by equation (14).

  Thereby, a composite value having a vector having the same sign as the vibration direction of the wearer in the vertical direction can be obtained.

  As described above, the corrected acceleration composite value obtained in step S8 is supplied to the walking pitch estimation unit 23 and the step count calculation unit 24, and as with the step count measuring apparatus 1 according to the first embodiment, the walking is performed. It is used for the pitch estimation process (S2), the limit period Tx determination process (S3), and the step count calculation process (S4).

  Next, effects of the step count measuring device 3 according to the third embodiment will be described.

FIG. 12 is a diagram illustrating a step count measurement result of a step count measuring apparatus including a conventional triaxial acceleration sensor as a comparative example of the step count measuring apparatus 3 according to the third embodiment.
FIG. 13 is a diagram showing the step count measurement result of the step count measuring apparatus 3 according to the third embodiment.

FIG. 12 shows a characteristic 3001 of a composite value of triaxial acceleration during a walking motion in which the wearer's body movement is large, and the number of steps 3002 measured based on the composite value.
Further, FIG. 13 shows the corrected acceleration calculated by the step count measuring apparatus 3 according to the third embodiment by using the acceleration measurement values of the respective measurement axes similar to those of the conventional step count measuring apparatus shown in FIG. and the combined value a'characteristics 4001 of _[n], is pedometer device 3 is shown a number of steps 4002 calculated based on the combined value a'acceleration after correction _[n] is.

  Note that the step count calculation result of the conventional step count measuring apparatus shown in FIGS. 12 and 13 and the step count calculation result by the step count measuring apparatus 3 according to the third embodiment are the same as those of the step count measuring apparatus 1 according to the first embodiment. This is obtained by applying a step count detection algorithm using the step count detection condition.

  As can be understood from FIGS. 12 and 13, in the conventional step count measuring apparatus, the combined value of acceleration is calculated according to the above (1), so the combined value of acceleration is a positive value. On the other hand, the step count measuring device 3 performs correction in consideration of the direction of vibration in the wearer's vertical direction with respect to the combined acceleration value calculated according to the above (1). ] Is a positive or negative value.

  In the conventional step counting device, as shown in FIG. 12, a peak in which the combined value of the three-axis accelerations is convex is generated in the non-contact period from time t2 to time t3. The occurrence of this peak is caused by the inversion of the sign of the combined acceleration value of each axis by calculating the combined acceleration value based on the above equation (1). That is, if the composite value of acceleration is calculated according to the above equation (1), the information of the sign of the measured value of acceleration of each axis is lost. Therefore, if even one large negative acceleration is measured, the composite of acceleration The value is converted to a large positive value. If the generation of the positive peak of the composite value of acceleration satisfies the above-described step detection condition, an erroneous detection of the step occurs as indicated by reference numeral 3003 in FIG.

  On the other hand, according to the step count measuring device 3 according to the third embodiment, correction is performed by adding a sign to the acceleration composite value in consideration of acceleration vibration in the vertical direction with respect to the ground during the wearer's walking motion. As shown in FIG. 13, the corrected composite value A [n] suppresses a convex peak due to the inversion of the sign of the composite value of acceleration. Thereby, it is possible to prevent erroneous detection of the number of steps in the non-contact period from time t2 to t3, which is seen in the measurement result of the conventional step counting device.

  As described above, according to the step count measuring apparatus 3 according to the third embodiment, the direction of vibration in the vertical direction of the wearer wearing the acceleration sensor 101 is determined based on the inclination of each measurement axis of the acceleration sensor 101 with respect to the vertical direction. In addition, the combined value of the acceleration of each measurement axis of the acceleration sensor 101 is corrected according to the determined vertical vibration direction, and the number of steps is detected based on the corrected combined value. It is possible to prevent erroneous detection of the number of steps during the non-ground period that occurs during operation.

  That is, according to the step count measuring apparatus 3 according to the third embodiment, as in the step count measuring apparatus according to the first embodiment, it is possible to prevent erroneous detection of the number of steps in a walking motion with a small body movement, and Since it is possible to prevent erroneous detection of the number of steps in such a walking motion with a large body motion, it is possible to realize more accurate detection of the number of steps compared to a conventional step counting device.

<< Embodiment 4 >>
FIG. 14 is a diagram illustrating a configuration of a step count measuring apparatus according to the fourth embodiment.
The step counting device 4 according to the fourth embodiment is such that the sensor unit 10 including the acceleration sensor 101 and the signal processing unit for calculating the number of steps such as the walking pitch estimation unit 13 are formed in separate terminals. This is different from the step counting devices 1 to 3 according to the first to third embodiments.

  Note that in the step count measuring apparatus 4 according to the fourth embodiment, the same components as those in the step count measuring apparatuses 1 to 3 according to the first to third embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

Specifically, the step count measuring device 4 includes a sensor terminal 5 and a child terminal 6.
The sensor terminal 5 includes a sensor unit 10 and an output unit that outputs measurement values (ax _[n] , _{ay [n]} , and _{az [n]} ) of acceleration of each measurement axis measured by the sensor unit 10. 103 is a wearable device.

  The child terminal 6 includes a sensor unit 10, a storage unit 11, a composite value calculation unit 12, a walking pitch estimation unit 13, a display unit 15, a position information acquisition unit 16, a movement speed calculation unit 17, an inclination calculation unit 20, and a vibration method determination unit. 21, a composite value correction unit 22, a step count calculation unit 24, and a data acquisition unit 25.

  The data acquisition unit 25 acquires the measurement value of the acceleration of each measurement axis output from the sensor terminal 5 and stores it in the storage unit 11. The composite value calculation unit 12, the position information acquisition unit 16, the movement speed calculation unit 17, the inclination calculation unit 20, the vibration method determination unit 21, the composite value correction unit 22, the walking pitch estimation unit 23, and the step count calculation unit 24 are Similar to the step count measuring apparatuses 1 to 3 according to the first to third aspects, various signal processes for calculating the number of steps are performed.

FIG. 15 is a diagram illustrating a specific implementation example of the step count measuring apparatus according to the second embodiment.
As shown in FIG. 15, the sensor terminal 5 is attached to clothing 7 or the like that can be worn by the user (living body). In FIG. 15, a shirt is illustrated as the garment 7, but the garment 7 may be anything that can be worn by the user, and may be, for example, a pant, a belly, a supporter, a band, or the like.

  The sensor terminal 5 and the child terminal 6 can communicate by wire or wireless. Specifically, the child terminal 6 is connected to the sensor terminal 5 by low-power radio such as Bluetooth (registered trademark), for example, and receives an acceleration measurement value output from the sensor terminal 5. The child terminal 6 is an information processing terminal such as a mobile phone, a smartphone, or a tablet terminal.

  The child terminal 6 calculates the number of steps based on the acceleration measurement value received from the sensor terminal 5 by the same method as the step number measuring apparatuses 1 to 3 according to the first to third embodiments, and displays the calculated step number information. Displayed on the unit 15. The child terminal 6 is connected to a communication network by wireless communication such as a cellular method or a wireless LAN method. For example, the calculated step count information and the position information of the child terminal 6 are transmitted to the server or the like via the communication network. May be.

  As described above, according to the step count measuring apparatus 4 according to the fourth embodiment, the sensor unit 10 and the other signal processing units are separated from each other, and the sensor terminal 5 and the child terminal 6 are configured separately. The terminal 5 can be reduced in size and can be kept out of the way for the user to carry. In addition, since the power saving of the sensor terminal 5 is possible, it is possible to operate for a long time, and it is possible to reduce the user's trouble of charging.

  Although the invention made by the present inventors has been specifically described based on the embodiment, it is needless to say that the present invention is not limited thereto and can be variously modified without departing from the scope of the invention. Yes.

  For example, in the above embodiment, the case where the acceleration sensor 101 is a triaxial acceleration sensor has been described as an example. However, the present invention is not limited to this. For example, the acceleration sensor 101 may be an acceleration sensor having two measurement axes, or may be an acceleration sensor having four or more measurement axes.

  Moreover, in the said embodiment, although the structure which memorize | stores the information of the measured value of acceleration, position information, etc. in the one memory | storage part 11 was illustrated, multiple memory | storage parts are provided according to the kind etc. of the information to memorize | store, and each information May be stored in a corresponding storage unit.

  Moreover, although the structure which added the position information acquisition part 16 and the movement speed calculation part 17 to the step count measuring apparatus 1 which concerns on Embodiment 1 as the step count measuring apparatus 2 which concerns on Embodiment 2 was illustrated, it is not restricted to this. . For example, the position information acquisition unit 16 and the movement speed calculation unit 17 can be added to the step count measuring apparatus 3 according to the third embodiment.

  Further, in the above embodiment, in the step count calculation algorithm by the step count calculation units 14 and 18, it is detected that the acceleration composite value becomes higher than the second threshold after the acceleration composite value becomes lower than the first threshold. Although the case where it was set as conditions was illustrated, it is not restricted to this. For example, the step count detection condition may be that the composite value of acceleration becomes lower than the first threshold value after the composite value of acceleration becomes higher than the second threshold value, or the composite value of acceleration is lower than the first threshold value. It is good also as a step count detection condition that the synthesized value of acceleration becomes higher than a 2nd threshold value, without detecting this. The same applies to the step count calculation unit 24 that uses the composite value of acceleration corrected by the composite value correction unit 22 instead of the composite value of acceleration.

  In general, when a gait occurs, the acceleration sensor first swings upward. As described above, priority is given to the detection of the fluctuation of the composite value in the positive direction (upward), so that it is possible to detect the number of steps quickly in time. Become.

Further, in the step count measuring apparatuses 1 to 4, the measured values (ax _[n] , _{ay [n]} , _{az [n]} ) of the acceleration of each measurement axis of the acceleration sensor 101 and the composite value a _[n] are used. When performing signal processing, it is possible to appropriately limit the bandwidth. For example, a high-frequency noise component may be removed by using a low-pass filter, a band-pass filter, or the like before or after performing various signal processing. For example, when the sampling rate is very fine and the noise of high frequency components is noticeable, the band limiting filtering may be performed a plurality of times before and after the calculation of the synthesized value of acceleration.

  Moreover, although the case where functional units such as the composite value calculation unit 12, the walking pitch estimation unit 13, and the step count calculation unit 14 are realized by program processing is illustrated, a part of the functional unit is performed by a dedicated hardware circuit. It may be realized.

  Further, in the step count measuring device 4 according to the fourth embodiment, the case where the composite value calculation unit 12 is provided in the child terminal 6 is illustrated, but the composite value calculation unit 12 is built in the sensor terminal 5 and each measurement is performed from the sensor terminal 5. The measurement value of the axis acceleration and the composite value calculated by the composite value calculator 12 may be output to the child terminal 6.

  1, 2, 3, 4 ... step counting device, 5 ... sensor terminal, 6 ... child terminal, 7 ... clothing, 10 ... sensor unit, 11 ... storage unit, 12 ... composite value calculation unit, 13, 23 ... walking pitch estimation , 14, 18, 24 ... step calculation unit, 15 ... display unit, 16 ... position information acquisition unit, 17 ... moving speed calculation unit, 20 ... tilt calculation unit, 21 ... vibration direction determination unit, 22 ... composite value correction unit , 25 ... data acquisition unit, 101 ... acceleration sensor, 102 ... A / D converter, 201 ... low pass filter, 202 ... angle calculation unit.

Claims (8)

A synthesized value calculation unit that calculates a synthesized value by synthesizing the measured values of acceleration of the respective measuring axes measured by an acceleration sensor having a plurality of measuring axes;
Detecting a change in the composite value that satisfies a condition for detecting the number of steps, and calculating a number of steps by walking or running by a wearer of the acceleration sensor based on the number of detections, and
The step number calculating unit detects a change in the composite value that satisfies a condition for detecting the number of steps, and then detects a change in the composite value that satisfies the condition for detecting the number of steps generated within a period determined by a step number pitch. Is not counted as the number of steps , and a sign corresponding to the direction of vibration of the wearer in the vertical direction is attached to the composite value . In the step counting device according to claim 1,
Based on the composite value, further has a walking pitch estimation unit that estimates the walking pitch of the walking motion by the wearer,
The step count calculating device changes the length of a period defined by the step pitch based on the walking pitch estimated by the walking pitch estimation unit. In the step counting device according to claim 2,
The walking pitch estimation unit
Based on the magnitude of variation from the average value of the composite value, the walking pitch is estimated,
The step count calculating device, wherein the step count calculating unit sets the time period determined by the step pitch pitch to be shorter as the walking pitch increases. In the step counting device of Claim 2 or 3,
It further has a movement speed calculation part for calculating the movement speed of the wearer,
When the moving speed does not exceed a threshold value, the step count calculating unit counts the change in the composite value that satisfies the condition for detecting the step count as the step count, and is calculated by the moving speed calculating unit When the moving speed exceeds the threshold value, the step count measuring device does not count the change in the composite value that satisfies the condition for detecting the step count as the step count. In the step counting device as described in any one of Claims 2 thru | or 4,
A sensor unit having the acceleration sensor;
An output unit that outputs a measured value of acceleration for each measurement axis measured by the acceleration sensor;
A storage unit that stores a measurement value of acceleration for each measurement axis output from the output unit;
The sensor unit and the output unit are formed in the first terminal,
The said memory | storage part, the said synthesized value calculation part, the said walk pitch estimation part, and the said step count calculation part are formed in the 2nd terminal different from the said 1st terminal. The step count measuring apparatus characterized by the above-mentioned. A first step of calculating a combined value by combining measured values of acceleration for each of the measurement axes measured by an acceleration sensor having a plurality of measurement axes;
A second step of detecting a change in the composite value that satisfies a condition for detecting the number of steps, and calculating a number of steps by walking or running by the wearer of the acceleration sensor based on the number of detections;
The second step does not count the variation of the composite value that satisfies the condition for detecting the number of steps generated within a period determined by the step pitch after detecting the variation of the composite value as the number of steps . A step counting method comprising the step of attaching a sign corresponding to the direction of vibration of the wearer in the vertical direction to the composite value . In the step count measuring method of Claim 6,
A third step of estimating a walking pitch of the walking motion by the wearer;
The second step includes a step of changing a length of a period defined by the step pitch based on the walking pitch estimated in the third step.   The program for making a computer perform each step in the step counting method of Claim 6 or 7.