JP2008237604A - Activity meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an activity meter capable of accurately computing the quantity of activity while reducing the manufacturing cost and reducing the processing time. <P>SOLUTION: The activity meter includes an acceleration detecting means 1 composed of an acceleration sensor 1a to be attached to a user's body and an A-D converting part 1b for converting the output of the acceleration sensor 1a to the digital acceleration value by sampling the output at a prescribed cycle and outputting the converted digital value; a behavior scene determining means 2 for determining the behavior scene of the user based on the acceleration value; and an activity quantity computing means 3 for extracting a part of a bit string composed of bits b<SB>1</SB>-b<SB>16</SB>indicating the acceleration value and computing the quantity of activity by using the extracted part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an activity meter that calculates an activity amount of a person.

2. Description of the Related Art Conventionally, an activity meter has been proposed that includes an acceleration sensor that is mounted on a human body and detects three-axis accelerations orthogonal to each other, and an arithmetic processing unit that calculates an activity amount based on the acceleration obtained by the acceleration sensor. (For example, refer to Patent Document 1).
JP 2006-204446 A

  By the way, in the activity meter as described above, when calculating the activity amount, it is necessary to convert the output of the acceleration sensor in the analog format into the acceleration value in the digital format.

  Here, in order to calculate an accurate amount of activity, it is preferable to lengthen the bit string indicating the acceleration value (increase the number of bits), but naturally, the number of data of the acceleration value increases, and the amount of activity is calculated. There was a problem that the required processing time became long.

  As a method for solving such a problem, it is conceivable to improve the processing speed by adopting a high-performance arithmetic processing unit. In this case, however, another problem that the manufacturing cost increases occurs. become.

  The present invention has been made in view of the above points, and an object thereof is to provide an activity meter capable of calculating an accurate activity amount while reducing manufacturing costs and processing time.

  In order to solve the above-described problem, in the invention of claim 1, the acceleration sensor mounted on the human body, and the output of the acceleration sensor are sampled at a predetermined period, converted into a digital acceleration value, and output. Extracting a part from the bit string indicating the acceleration value according to the determination result of the acceleration detection means comprising the conversion unit, the action scene determination means for determining the action scene of the person based on the acceleration value, and the action scene determination means, An activity amount calculating means for calculating an activity amount using the part is provided.

  According to the first aspect of the present invention, since the activity amount is calculated by extracting a part from the bit string indicating the acceleration value, the activity amount is compared with the case where the activity amount is calculated using all the bit strings indicating the acceleration value. The processing time required for the calculation can be shortened, so that it is not necessary to use a high-performance arithmetic processing unit, and the manufacturing cost can be reduced. In addition, when extracting a part from the bit string indicating the acceleration value, a portion to be extracted is selected based on the action scene determined based on the acceleration value. For example, the action scene has a relatively high acceleration. When driving, the bit string indicating the acceleration value is less affected by the lower bit string indicating the acceleration value. Therefore, the bit string indicating the acceleration value is calculated by calculating the amount of activity using the upper bit string among the bit string indicating the acceleration value. It is possible to obtain an activity amount approximately equal to the activity amount calculated using all of the above, and as a result, an accurate activity amount can be calculated.

  In the invention of claim 2, in the invention of claim 1, the action scene determining means is configured to determine whether the action scene is a daily activity, walking, or running, and the activity amount calculating means If the scene is a daily activity, extract the lower part from the bit string indicating the acceleration value, and if the action scene is running, extract the upper part from the bit string indicating the acceleration value, When the action scene is walking, a part on the center side is extracted from the bit string indicating the acceleration data.

  According to the invention of claim 2, if the action scene is a daily activity with relatively small acceleration, the influence of the upper bit string in the bit string indicating the acceleration value is small, so the lower bit string is used. If the amount of activity is calculated and the action scene is traveling at a relatively high acceleration, the lower bit string has little influence. Therefore, the amount of activity is calculated using the upper bit string, and the action scene is relatively If walking is an acceleration between activity and running, the upper bit string and the lower bit string are less affected, so the amount of activity is calculated using the central bit string. Compared to the case of calculating the amount of activity using, the processing time required for calculating the amount of activity can be shortened and the manufacturing cost can be reduced. In addition, the amount of activity can be calculated accurately.

  The invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the action scene determination means is configured to determine a human action scene based on the magnitude of acceleration obtained by the acceleration detection means. And

  According to the invention of claim 3, since the activity amount is calculated by extracting a part from the bit string indicating the acceleration value, the activity amount is compared with the case where the activity amount is calculated using all the bit strings indicating the acceleration value. The processing time required for the calculation can be shortened, so that it is not necessary to use a high-performance arithmetic processing unit, and the manufacturing cost can be reduced. In addition, when extracting a part from the bit string indicating the acceleration value, a portion to be extracted is selected based on the action scene determined based on the acceleration value. For example, the action scene has a relatively high acceleration. When traveling, there is little influence from the lower bit string in the bit string indicating the acceleration value, so the bit string indicating the acceleration value is calculated by calculating the amount of activity using the upper bit string in the bit string indicating the acceleration value. It is possible to obtain an activity amount approximately equal to the activity amount calculated using all of the above, and as a result, an accurate activity amount can be calculated.

  In the invention of claim 4, in the invention of any one of claims 1 to 3, the action scene determination means calculates the number of steps per unit time from the acceleration obtained by the acceleration detection means, and the person is determined based on the number of steps. The action scene is determined to be determined.

  According to the invention of claim 4, since the activity amount is calculated by extracting a part from the bit string indicating the acceleration value, the activity amount is compared with the case where the activity amount is calculated using all the bit strings indicating the acceleration value. The processing time required for the calculation can be shortened, so that it is not necessary to use a high-performance arithmetic processing unit, and the manufacturing cost can be reduced. In addition, when extracting a part from the bit string indicating the acceleration value, the part to be extracted is selected based on the action scene determined based on the acceleration value. For example, the action scene has a relatively high acceleration. When driving, the bit string indicating the acceleration value is less affected by the lower bit string indicating the acceleration value. Therefore, the bit string indicating the acceleration value is calculated by calculating the amount of activity using the upper bit string among the bit string indicating the acceleration value. It is possible to obtain an activity amount approximately equal to the activity amount calculated using all of the above, and as a result, an accurate activity amount can be calculated.

  The present invention has an effect that an accurate amount of activity can be calculated while reducing manufacturing costs and processing time.

(Embodiment 1)
As shown in FIG. 1A, the activity meter of the present embodiment samples the acceleration sensor 1a worn on the human body and the output of the acceleration sensor 1a at a predetermined cycle and converts it into a digital acceleration value. Acceleration value according to the determination result of the acceleration detection means 1 comprising the A / D converter 1b to output, the action scene determination means 2 for determining a human action scene based on the acceleration value, and the action scene determination means 2 Activity amount calculating means 3 for extracting a part from the bit string composed of bits b _{1 to} b ₁₆ (see FIG. 1B) indicating the amount of activity and calculating the amount of activity using the part, and activity amount calculating means Display means 4 for displaying the amount of activity calculated in 3, storage means 5 comprising a storage device such as RAM or HDD in which various data such as acceleration obtained by the acceleration detection means 1 are stored, and an activity meter Ono Operation means (not shown) for performing the operation, power supply means (not shown) such as a battery for driving the activity meter, and a housing (not shown) for storing them. . In addition, the said housing | casing consists of resin molded products etc., for example, and is formed in the magnitude | size which a person can carry.

  The acceleration sensor 1a is, for example, a triaxial acceleration sensor that outputs triaxial accelerations perpendicular to each other in an analog format. As such an acceleration sensor 1a, a small-sized and low power consumption acceleration sensor using MEMS (Micro Electro Mechanical Systems) can be used. As the acceleration sensor 1a, a piezoresistive acceleration sensor, a capacitance acceleration sensor, or the like can be employed. As the triaxial acceleration sensor, a sensor that can output a triaxial acceleration value by combining a biaxial acceleration sensor and a monoaxial acceleration sensor may be used. It is also possible to use one that can output a three-axis acceleration value.

The A / D conversion unit 1b is composed of an acceleration detection circuit configured to sample the output of the acceleration sensor 1a at a predetermined period, convert it into a digital acceleration value, and outputs it, for example, as shown in FIG. As shown, the output of the acceleration sensor 1a is converted into an acceleration value of a bit string (that is, a 16-bit bit string) composed of ₁₆ bits b _{1 to} b ₁₆ and output. Note that the A / D conversion unit 1b can employ a conventionally known one, and a detailed description thereof will be omitted.

  The action scene determination unit 2 is a predetermined time of a norm (that is, a combined acceleration value) in which the magnitude of the acceleration value of the acceleration detection unit 1, in this embodiment, the acceleration value of each axis obtained by the acceleration detection unit 1 is a vector component. The action scene is determined based on the fluctuation average (standard deviation) S.

  For example, as shown in FIG. 2, the action scene determination unit 2 is a low-intensity action that does not involve walking in an action scene if the variation average S is less than a first threshold (0.3G in the present embodiment). If it is determined as “life activity” and the variation average S is equal to or greater than a second threshold value (0.6 G in the present embodiment) that is greater than the first threshold value, the action scene is determined to be “running”, and the variation average S is If the threshold value is 1 or more and less than the second threshold value, the action scene is determined as “walking”. Such a determination result is output to the activity amount calculation means 3.

  Here, the first threshold value is a value that becomes a boundary between “life activity” and “walking”. For example, the variation average S when the human action scene is switched from “life activity” to “walking”. Can be obtained from statistical data. Similarly, the second threshold value is a value that becomes a boundary between “walking” and “running”. For example, the statistical value of the variation average S when a human action scene is switched from “walking” to “running”. It can be obtained from data. Moreover, the value of each threshold value in this embodiment is an example to the last, and it is not the meaning limited to this numerical value. This also applies to Embodiments 2 and 3 described later.

  When receiving the determination result of the action scene determination unit 2, the activity amount calculation unit 3 calculates the acceleration obtained by the acceleration detection unit 1, that is, the acceleration of each axis obtained by the acceleration detection unit 1 in this embodiment, as a vector component. The amount of activity is calculated based on a fluctuation average (standard deviation) S over a predetermined time of the norm, and when calculating the amount of activity, a part of the bit string indicating the acceleration value (in the present embodiment, continuous 8). A sequence of bits) is extracted, and the amount of activity is calculated using the part (that is, assuming that other than the extracted bit sequence is 0).

That is, the activity amount calculation means 3 does not calculate the activity amount using all the bit strings composed of the bits b _{1 to} b ₁₆ indicating the acceleration value, but calculates the activity amount using a part of the bit string. For example, when the determination result is “life activity”, the lower-order bit string b _L (that is, a part of the lower-order side of the bit string) including the bits b _{1 to} b ₈ is used. If it is running, "when the bit b ₉ ~b _16-bit string of the upper side consisting of b _{H (in} other words, a part of the upper side of the bit string), the determination result is" walking ", the bit b ₅ ~ bit string of the center-side consisting of b ₁₂ b _{c (i.e.} part of the central side of the bit sequence) using respectively, and calculates the variation average S. In addition, after calculating the variation average S using a part of the bit string, in order to match the number of bits with the case where the variation average S is calculated using all the bit strings (in order to match the data format), the bit Correction for converting the number into 16 bits is performed, and the corrected variation average S is used to calculate the amount of activity. This correction is, for example, _b 1 ~b is a bit _b 1 ~b ₈ both are 0 in the case of using the _b 9 _{~b 16} is a bit string _{b H} the upper side, a bit string _{b L} of the lower Bits b _{9 to} b ₁₆ that are all 0 when ₈ is used, and bits b _{1 to} b ₄ that are all 0 when b _{5 to} b ₁₂ that are the bit string b _C on the center side are used. , B _{13 to} b ₁₆ are added.

  In calculating the activity amount from the fluctuation average S, for example, a data table indicating the relationship between the fluctuation average S and the oxygen consumption, an arithmetic expression obtained by a least square method, or the like is used. Such data can be obtained from the correlation between the oxygen consumption measured by changing the intensity of the exercise by the expiration gas measuring device and the fluctuation average S corresponding to the intensity of the exercise.

  In the present embodiment, “METs” is a value that indicates how many times the energy consumption during exercise, which is used in the American Sports Medicine Association, is greater than the energy consumption at rest (metabolism at rest) as the activity amount. (Metabolic equivalents) "values are used. Here, since 1 [METs] corresponds to an oxygen consumption amount of 3.5 [ml / kg / min], it can be calculated from the oxygen consumption amount obtained from the data table or the arithmetic expression.

Therefore, if the activity amount calculating means 3 of the present embodiment is a “life activity” with relatively small acceleration, the higher-order bit string (for example, consecutive bits b _{9 to} b ₁₆ ) of the bit string indicating the acceleration value. Therefore, the amount of activity is calculated using a lower-order bit string (for example, a bit string composed of consecutive bits b _{1 to} b ₈ ). If the action scene is “running” with relatively high acceleration, the lower bit string (for example, a bit string consisting of consecutive bits b _{1 to} b ₈ ) is less affected, so the upper bit string (for example, to calculate the amount of activity by using a bit string) consisting of bits _b 9 _{~b 16} consecutive. Also, if the action scene is “walking” that is an acceleration between “life activity” and “running”, the upper bit string (for example, a bit string consisting of consecutive bits b _{13 to} b ₁₆ ) and the lower bit side of the bit string (e.g., a bit sequence consisting of bits b ₁ ~b ₄ consecutive) the influence of a small, calculates the activity amount with a bit string of the center side (e.g., the bit sequence consisting of bits b ₅ ~b ₁₂ consecutive) To do.

  Therefore, the activity amount calculation means 3 can shorten the processing time necessary for calculating the activity amount, compared to the case where the activity amount is calculated using all the bit strings indicating the acceleration values.

  By the way, the activity amount calculating means 3 has the function of calculating the activity amount as described above, the average of activity amounts per unit time such as one hour or one day, exercise [METs · h], one day exercise. It may be configured to calculate various data (hereinafter referred to as “activity data”) relating to human activities such as amount, calorie consumption, number of steps, and exercise time. In addition, since calculation methods, such as exercise and consumption calories, can use a conventionally well-known method, detailed description is abbreviate | omitted. Further, the activity amount calculation means 3 is configured to store a history of each activity data by storing the activity data in the storage means 5.

  The action scene determination unit 2 and the activity amount calculation unit 3 include, for example, an arithmetic processing device (not shown) made up of hardware resources such as a microcomputer housed in the casing, and an arithmetic unit for information calculation. This is realized by software that performs processing and the like. In addition to the action scene determination means 2 and the activity amount calculation means 3, the arithmetic processing unit exhibits various functions of the activity meter such as a display control means (not shown) for controlling the display means 4. It has the necessary means.

  The display means 4 is composed of an image display device (not shown) such as a liquid crystal display (LCD) and its drive circuit (not shown), and is stored in the storage means 5 by the display control means. The activity data is controlled to be displayed on the image display device. In addition, the operation means includes a switch for on / off operation of the activity meter, a switch for starting calculation of the activity amount, a switch for resetting the display of the activity amount, a switch for switching the activity data to be displayed, etc. It is.

In the activity meter of the present embodiment described above, for example, if the fluctuation average S is less than the first threshold, the action scene determination unit 2 determines that the action scene is “life activity”, and the activity amount calculation unit 3 Then, the amount of activity is calculated using the bit string b _L on the lower side of the acceleration value. If the variation average S is not less than the first threshold value and less than the second threshold value, the action scene determination unit 2 determines that the action scene is “walking”, and the activity amount calculation unit 3 determines the bit string on the center side of the acceleration value. amount of activity calculated using the b _C is performed. If the variation average S is equal to or greater than the second threshold value, the action scene determination unit 2 determines that the action scene is “running”, and the activity amount calculation unit 3 uses the upper bit string b _H of the acceleration value. The amount of activity is calculated.

  Therefore, according to the activity meter of the present embodiment, the activity amount is calculated by extracting a part from the bit string indicating the acceleration value, so that the activity amount is calculated using all the bit strings indicating the acceleration value. Thus, the processing time required for calculating the amount of activity can be shortened, so that it is not necessary to use an expensive high-performance processing unit, and the manufacturing cost can be reduced.

  In addition, when extracting a part from the bit string indicating the acceleration value, the part to be extracted is selected based on the action scene determined based on the acceleration value. During acceleration when the acceleration is high, there is little influence from the lower bit string in the bit string indicating the acceleration value, so by calculating the amount of activity using the upper bit string in the bit string indicating the acceleration value, It is possible to obtain an activity amount substantially equal to the activity amount calculated using all of the bit string indicating the acceleration value, and as a result, an accurate activity amount can be calculated.

In this embodiment, a 16-bit bit string is taken as an example, and a bit string consisting of bits b _{1 to} b ₈ when the action scene is “living activity” and a bit b ₉ when the action scene is “running”. the bit train consisting ~b _16, but action scenes are so used respectively a bit sequence consisting of bits b ₅ ~b ₁₂ when "walking", such an example is merely an example, limiting to this Not the purpose. As for which bit string to use, a suitable one may be selected in consideration of the characteristics of the actual acceleration sensor 1a and the A / D converter 1b.

  In the present embodiment, “life activity”, “walking”, and “running” are listed as the action scenes, but this is just an example, and the action scenes are not limited to these. Furthermore, although the acceleration detection means 1 in the present embodiment uses an acceleration sensor that detects accelerations of three axes orthogonal to each other, the acceleration detection unit 1 detects accelerations of one axis or two axes orthogonal to each other. An acceleration sensor may be used.

(Embodiment 2)
In the activity meter of the present embodiment, the configuration of the action scene determination unit 2 is different from that of the first embodiment, and the other configurations are the same as those of the first embodiment.

  The action scene determination means 2 in the present embodiment calculates the number of steps [steps / min (minutes)] per unit time (1 minute in the present embodiment) from the acceleration obtained by the acceleration detection means 1, and per unit time. The action scene is determined based on the number of steps. Here, the number of steps is counted, for example, by counting the number of peaks whose peak value exceeds a predetermined threshold in the norm having the acceleration of each axis obtained by the acceleration detecting means 1 as a vector component. As a method of counting the number of steps of a person from the acceleration obtained by the acceleration detecting means 1, a conventionally known method can be adopted, and detailed description thereof is omitted.

  For example, as shown in FIG. 3, if the number of steps per unit time is less than a first threshold (60 in the present embodiment), the action scene determination unit 2 determines the action scene as “life activity”, and If the number of steps per unit time is equal to or greater than a second threshold value (120 in the present embodiment) that is greater than the first threshold value, the action scene is determined to be “running”, and the number of steps per unit time is equal to or greater than the first threshold value. If it is less than the second threshold, the action scene is determined as “walking”.

  Here, the first threshold value is a value serving as a boundary between “life activity” and “walking”. For example, the unit time when the human action scene is switched from “life activity” to “walking” is described above. It can be obtained from the statistical data of the number of steps per hit. Similarly, the second threshold is a value that becomes a boundary between “walking” and “running”. For example, the second threshold value per unit time when the human action scene switches from “walking” to “running” It can be obtained from statistical data on the number of steps.

  According to the activity meter of the present embodiment described above, the same effect as in the first embodiment can be obtained, and the activity meter of the present embodiment determines the action scene based on the number of steps per unit time. Since the action scene can be determined from a viewpoint different from the acceleration, the action scene can be determined even when the acceleration variation average S is the same, and the activity amount can be calculated more accurately.

(Embodiment 3)
In the activity meter of the present embodiment, the configuration of the action scene determination unit 2 is different from that of the first embodiment, and the other configurations are the same as those of the first embodiment.

  The action scene determination means 2 in the present embodiment has a first determination function for determining an action scene based on the variation average S as in the first embodiment, and the number of steps per unit time (1 minute in the present embodiment) as in the second embodiment. And a second determination function for determining an action scene.

  Then, the action scene determination means 2 outputs the determination result to the activity amount calculation means 3 only when the determination results of the first determination function and the second determination function match, and the activity amount calculation means 3 Calculation is performed. That is, the action scene determination means 2 does not correspond to any action scene when the determination results of the first determination function and the second determination function do not match, and the acceleration obtained by the acceleration detection means 1 is It is determined that it is not caused by human behavior. In this case, the activity amount calculation means 3 does not calculate the activity amount.

  Therefore, according to the activity meter of the present embodiment, since the two types of determinations of the first determination function and the second determination function are performed, the action scene can be determined accurately, and as a result, the more accurate activity The amount can be calculated.

  In this embodiment, two types of determinations are performed. However, more determinations may be performed, and the determination method is not limited to the above method, and the gist of the present invention. You may change to the extent which does not deviate.

(A) is a block diagram of the active mass meter of Embodiment 1, (b) is explanatory drawing in the same as the above. It is explanatory drawing of the determination method of the action scene in the same as the above. It is explanatory drawing of the determination method of the action scene in the active mass meter of Embodiment 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Acceleration detection means 1a Acceleration sensor 1b A / D conversion part 2 Action scene determination means 3 Activity amount calculation means

Claims (4)

  An acceleration sensor mounted on a human body, an acceleration detection means comprising an A / D conversion unit that samples the output of the acceleration sensor at a predetermined cycle and converts it into a digital acceleration value, and outputs the acceleration sensor. Action scene determining means for determining the action scene, and an activity amount calculating means for extracting a part from the bit string indicating the acceleration value according to the determination result of the action scene determining means and calculating the activity amount using the part An activity meter characterized by comprising.   The action scene determining means is configured to determine whether the action scene is a daily activity, walking, or running, and the activity amount calculating means indicates an acceleration value when the action scene is a daily activity. When a part of the lower side is extracted from the bit string and the action scene is running, a part of the upper side is extracted from the bit string indicating the acceleration value, and when the action scene is walking, the acceleration data is indicated. 2. The activity meter according to claim 1, wherein a part of the center side is extracted from the bit string.   The activity meter according to claim 1, wherein the action scene determination unit is configured to determine a human action scene based on the magnitude of the acceleration obtained by the acceleration detection unit.   The action scene determination means is configured to calculate the number of steps per unit time from the acceleration obtained by the acceleration detection means, and to determine a human action scene based on the number of steps. The activity meter according to any one of the above.

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