JP2009116389A - Body movement detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect body movement to obtain accurate count of the body movement. <P>SOLUTION: Magnitude of vertical acceleration is obtained, and a lower chord peak value wherein the magnitude changes over from a decrease tendency to an increase tendency and an upper chord peak value wherein the magnitude changes over from the increase tendency to the decrease tendency are detected. A difference between the detected lower chord peak value and upper chord peak value is calculated. The calculated difference is compared with a threshold value, it is decided that the body movement is detected when the difference is the threshold value or above, and a body movement detection flag is turned on. It is decided that the body movement is not detected when the difference is smaller than the threshold value, and the body movement flag is kept turning off. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a body motion detection device.

  The pedometer (body motion detection device) detects the acceleration of the pedestrian in the vertical direction using an acceleration sensor, and counts the number of steps (body motion) based on the change in the detected value. FIG. 9 is a waveform diagram showing changes in the detected acceleration value in a conventional pedometer. As shown in FIG. 9, the conventional pedometer generates a walking signal by recognizing that the pedestrian has walked one step each time the detected acceleration value exceeds a threshold (see, for example, Patent Document 1). For example, in the example shown in FIG. 9, the first peak 1, the second peak 2, the third peak 3, the fourth peak 4, the fifth peak 5, the sixth peak 6 and the seventh peak 7. Out of the first peak 1, the fourth peak 4, the fifth peak 5 and the sixth peak 6 exceeding the threshold, the first step, the second step, the third step and the fourth step, respectively. Thus, the number of steps is counted. In FIG. 9, the triangle mark indicates the generation timing of the walking signal, and the numbers (1, 2, 3, 4) below indicate the number of steps.

Japanese Patent No. 2675842 (15th to 22nd lines from the top of the left column on the 3rd page)

  However, the conventional pedometer has the following problems. For example, in the example shown in FIG. 9, the fourth peak 4 and the fifth peak 5 are actually only walked one step, but in an extremely short time 2 due to irregular movement during walking. Since two peaks occurred and both of them exceeded the threshold value, it was decided to walk two steps. In addition, at the third peak 3, although the user actually walked one step, the peak does not exceed the threshold value, and therefore, the user is not walking. In this way, if the waveform of the acceleration detection value does not become a clean sine curve, it may be misrecognized that the user has not walked, but may have misrecognized that he has not walked, I can't get my steps.

  An object of the present invention is to provide a body motion detection device that can accurately detect body motion and obtain an accurate count of body motion, in order to eliminate the above-described problems caused by the prior art.

  In order to solve the above-described problems and achieve the object, a body motion detection device according to claim 1 is a body motion detection device that determines detection of body motion based on the magnitude of acceleration output from an acceleration sensor. Detecting the lower chord peak value where the magnitude of acceleration switches from a decreasing trend to an increasing trend, and the upper chord peak value switching from an increasing trend to a decreasing trend, and determining the detection of body movement based on the lower chord peak value and the upper chord peak value It is characterized by doing.

  According to a second aspect of the present invention, there is provided the body movement detecting device according to the first aspect, wherein a difference between the lower chord peak value and the upper chord peak value is calculated, and the difference is compared with a threshold value. The detection is determined.

  According to a third aspect of the present invention, in the body movement detecting device according to the second aspect, the difference is calculated from the upper chord peak value immediately before or immediately after the lower chord peak value.

  According to a fourth aspect of the present invention, there is provided the body movement detecting device according to the second or third aspect, wherein the body movement is detected when the difference is larger than the threshold value.

  According to a fifth aspect of the present invention, in the body movement detection device according to any one of the first to fourth aspects, the acceleration magnitude is predetermined after it is determined that the body movement has been detected. It is characterized in that the body movement is counted when it becomes smaller for the first time than the predetermined value across the value or when it becomes larger for the first time.

  A body movement detecting device according to a sixth aspect of the present invention is the invention according to any one of the first to fourth aspects, wherein the body movement is counted when it is determined that the body movement is detected. Features.

  According to a seventh aspect of the present invention, in the body motion detection device according to any one of the first to sixth aspects, the acceleration sensor detects accelerations in three different directions, and the accelerations in the three directions. The magnitude of the acceleration is acquired based on the above.

  The body motion detection device according to claim 8 is the invention according to claim 7, wherein the magnitude of the acceleration is a magnitude obtained by subtracting gravitational acceleration from the detected acceleration. .

  According to a ninth aspect of the present invention, in the body movement detecting device according to the eighth aspect of the present invention, an average value of a plurality of consecutive detected values of acceleration is regarded as the gravitational acceleration in each of the three directions. It is characterized by.

  According to the present invention, the magnitude of the acceleration is acquired, the lower chord peak value and the upper chord peak value of the magnitude of the acceleration are detected, and the difference between the continuous peak values is calculated. The difference is compared with a threshold value, and when the threshold value is exceeded, it is determined that body movement has been detected.

  According to the body movement detecting device of the present invention, it is possible to accurately detect body movement and to obtain an accurate count of body movement.

  Exemplary embodiments of a body motion detection device according to the present invention will be explained below in detail with reference to the accompanying drawings. Note that, in the following description of the embodiments and the accompanying drawings, the same reference numerals are given to the same components, and duplicate descriptions are omitted.

(Hardware configuration of body motion detection device)
FIG. 1 is a block diagram showing a hardware configuration of a body motion detection device according to the present invention. As shown in FIG. 1, the body motion detection device 11 includes a three-axis acceleration sensor that can detect accelerations in three different directions (X-axis direction, Y-axis direction, and Z-axis direction). Here, the three-axis acceleration sensor includes an X-axis acceleration sensor 12 that detects acceleration in the X-axis direction, a Y-axis acceleration sensor 13 that detects acceleration in the Y-axis direction, and a Z-axis acceleration sensor that detects acceleration in the Z-axis direction. It is shown as 14. A well-known sensor can be used as the acceleration sensor. The X-axis direction, the Y-axis direction, and the Z-axis direction are directions specific to the body motion detection device 11 and change with changes in the posture (direction and inclination) of the body motion detection device 11.

  Further, the body motion detection device 11 determines whether or not the subject motion is the body motion of the subject carrying the body motion detection device 11 based on the output signal of the three-axis acceleration sensor, and the processing device 15 that counts the body motion is provided. I have. The detailed configuration of the processing device 15 will be described later. The body motion detection device 11 includes a display device 16 that displays the body motion counted by the processing device 15. The display device 16 includes, for example, a liquid crystal panel and a liquid crystal driving circuit.

(Functional configuration of processing equipment)
FIG. 2 is a block diagram showing a functional configuration of the processing device of the body movement detection device according to the present invention. As shown in FIG. 2, the processing device 15 includes an X-axis analog / digital conversion unit 21, a Y-axis analog / digital conversion unit 22, a Z-axis analog / digital conversion unit 23, and an acceleration acquisition unit 24 that functions as an acquisition unit. , An upper chord peak value detecting unit 25 and a lower chord peak value detecting unit 26 having a function as a detecting unit, a peak difference detecting unit 27 having a function as a calculating unit, a threshold determining unit 28 having a function as a determining unit, and a flag control unit 29 and a counting unit 30. These functional units may be realized by hardware, or may be realized by executing a program with a CPU or the like.

  The X-axis analog / digital conversion unit 21, the Y-axis analog / digital conversion unit 22, and the Z-axis analog / digital conversion unit 23 are respectively connected to the X-axis acceleration sensor 12 and the Y-axis acceleration sensor via input terminals 31, 32, and 33. 13 and the Z-axis acceleration sensor 14, and analog voltage signals output from these sensors are sampled at a predetermined cycle and converted into digital data. It is desirable that the X-axis analog / digital conversion unit 21, the Y-axis analog / digital conversion unit 22, and the Z-axis analog / digital conversion unit 23 sample each sensor output signal at the same timing.

  The acceleration acquisition unit 24 acquires the magnitude of acceleration based on the output values of the analog / digital conversion units 21, 22, and 23 for each axis. The magnitude of acceleration is repeatedly increased and decreased. The detailed configuration of the acceleration acquisition unit 24 will be described later. The upper string peak value detection unit 25 detects a peak value (referred to as an upper string peak value) when the magnitude of the acceleration acquired by the acceleration acquisition unit 24 switches from an increasing tendency to a decreasing tendency. In order to detect the upper string peak value, the upper string peak value detection unit 25 performs, for example, the following processing. The crest peak value detection unit 25 stores the acceleration value output from the acceleration acquisition unit 24 in a buffer, compares the stored value of the buffer with the acceleration value output from the acceleration acquisition unit 24, and Update the stored value of the buffer with the larger value. When the acceleration value output from the acceleration acquisition unit 24 becomes smaller than the stored value of the buffer, the upper chord peak value detecting unit 25 sets the stored value of the buffer at that time as the upper chord peak value.

  The lower chord peak value detection unit 26 detects a peak value (referred to as a lower chord peak value) when the magnitude of the acceleration acquired by the acceleration acquisition unit 24 switches from a decreasing tendency to an increasing tendency. In order to detect the lower chord peak value, the lower chord peak value detecting unit 26 performs, for example, the following processing. The lower chord peak value detection unit 26 stores the acceleration value output from the acceleration acquisition unit 24 in a buffer, compares the stored value of the buffer with the acceleration value output from the acceleration acquisition unit 24, and Update the stored value of the buffer with the smaller value. When the acceleration value output from the acceleration acquisition unit 24 becomes larger than the stored value of the buffer, the lower chord peak value detecting unit 26 sets the stored value of the buffer at that time as the lower chord peak value.

  The peak difference detection unit 27 calculates the difference between the lower chord peak value detected by the lower chord peak value detection unit 26 and the upper chord peak value detected by the upper chord peak value detection unit 25. At that time, the peak difference detection unit 27 may calculate the difference between the lower chord peak value and the immediately following upper chord peak value, or may calculate the difference between the upper chord peak value and the immediately following lower chord peak value. . The threshold value determination unit 28 compares the difference between the lower chord peak value and the upper chord peak value calculated by the peak difference detection unit 27 with a preset threshold value, and determines whether body motion has been detected based on the result. Determine. For example, the threshold determination unit 28 determines that body movement has been detected when the difference between the lower chord peak value and the upper chord peak value is greater than the threshold.

  The flag control unit 29 turns on the body motion detection flag at a predetermined timing when the threshold determination unit 28 determines that the body motion is detected. The predetermined timing is a timing determined by the magnitude of the acceleration acquired by the acceleration acquisition unit 24. An example of this timing will be described later. In addition, the flag control unit 29 switches the body motion detection flag off when a predetermined period has elapsed after turning on the body motion detection flag. The counting unit 30 includes a counter and counts the number of times the body motion detection flag is turned on. The count value data of the counting unit 30 is sent to the display device 16 via the output terminal 34.

(Functional configuration of acceleration acquisition unit)
FIG. 3 is a block diagram showing a functional configuration of the acceleration acquisition unit of the body motion detection device according to the present invention. As shown in FIG. 3, the acceleration acquisition unit 24 includes an X-axis acceleration data storage unit 41, a Y-axis acceleration data storage unit 42, a Z-axis acceleration data storage unit 43, a gravitational acceleration calculation unit 44, and a gravitational acceleration dispersion ratio determination unit 45. , A gravitational acceleration data calculation unit 46, a vertical deviation gravity acceleration data calculation unit 47, a vertical direction weighted synthetic acceleration data calculation unit 48, a synthetic acceleration data storage unit 49, and a smoothing unit 50.

  The X-axis acceleration data storage unit 41, the Y-axis acceleration data storage unit 42, and the Z-axis acceleration data storage unit 43 are constituted by ring buffers, for example. The X-axis acceleration data storage unit 41, the Y-axis acceleration data storage unit 42, and the Z-axis acceleration data storage unit 43 are respectively connected to the X-axis analog / digital conversion unit 21 and the Y-axis analog / digital conversion unit 21 via input terminals 51, 52, and 53. It is connected to the digital conversion unit 22 and the Z-axis analog / digital conversion unit 23, and the output values of these analog / digital conversion units are stored as acceleration data.

  The gravitational acceleration calculation unit 44 reads a predetermined number (for example, eight) of continuous acceleration data from the X-axis acceleration data storage unit 41, calculates a moving average value thereof, and sets the value as the value of gravitational acceleration. The moving average value is obtained by dividing the added value of n values by n, where n is a natural number. The gravitational acceleration value is similarly calculated for the Y-axis direction and the Z-axis direction. At this time, the predetermined number of acceleration data in the X-axis direction, the predetermined number of acceleration data in the Y-axis direction, and the predetermined number of acceleration data in the Z-axis direction are preferably data sampled at the same timing. Originally, in order to obtain the gravitational acceleration, the subject needs to be stationary. However, it is unrealistic for the subject to rest for that purpose. Here, by calculating the moving average value of acceleration data for a relatively long time, it is possible to smooth the acceleration generated by body movement such as walking, so the moving average value of acceleration data in each axis direction is It can be regarded as a value of gravity acceleration in each axis direction in a pseudo manner.

  The gravitational acceleration dispersion ratio determination unit 45 obtains the difference between the value of the gravitational acceleration in the X-axis direction obtained by the gravitational acceleration calculation unit 44 and the intermediate value of the output value of the X-axis analog / digital conversion unit 21, and the value Is the gravitational acceleration dispersion ratio in the X-axis direction. The gravitational acceleration dispersion ratio is similarly determined for the Y-axis direction and the Z-axis direction. As described above, in the case of the configuration in which the output signal of the acceleration sensor is sampled by the analog / digital conversion unit, the greater the acceleration detected by the acceleration sensor, the greater the value of the sampled acceleration is the output value of the analog / digital conversion unit. Move away from the intermediate value. Therefore, the higher the gravitational acceleration dispersion ratio among the X, Y, and Z axes, the greater the influence of vertical acceleration (gravity acceleration). That is, the higher the gravitational acceleration dispersion ratio, the closer to the vertical axis.

  The gravitational acceleration data calculation unit 46 subtracts the value of the gravitational acceleration in the X-axis direction obtained by the gravitational acceleration calculation unit 44 from the acceleration data in the X-axis direction output from the X-axis analog / digital conversion unit 21. The obtained value is taken as the gravitational acceleration data in the X-axis direction. Similarly, the gravity acceleration data is calculated for the Y-axis direction and the Z-axis direction. The gravitational acceleration data means data obtained by removing the gravitational acceleration from the acceleration acquired by the acceleration sensor.

  When calculating the gravitational acceleration data, it is necessary to pay attention to the direction of acceleration. If the gravitational acceleration value obtained by the gravitational acceleration calculation unit 44 is equal to or greater than the intermediate value of the output value of the analog / digital conversion unit, the gravitational acceleration value is calculated from the acceleration data value output from the analog / digital conversion unit. The value obtained by subtracting the value is the value of the gravitational acceleration data. When the value of the gravitational acceleration obtained by the gravitational acceleration calculation unit 44 is smaller than the intermediate value of the output value of the analog / digital conversion unit, the acceleration data output from the analog / digital conversion unit is calculated from the value of the gravitational acceleration. The value obtained by subtracting the value is the value of the gravitational acceleration data.

  The vertical deviation gravitational acceleration data calculation unit 47 adds the gravity acceleration data in the X axis direction obtained by the gravity acceleration dispersion ratio determination unit 45 to the value of the degravity acceleration data in the X axis direction obtained by the gravitational acceleration data calculation unit 46. The acceleration dispersion ratio is multiplied, and the obtained value is set as the value of the vertical eccentric gravity acceleration data in the X-axis direction. Similarly, the value of vertical deviation gravity acceleration data is calculated for the Y-axis direction and the Z-axis direction. The vertical deviation gravity acceleration data is data obtained by adding the influence of gravity acceleration to the gravity removal acceleration data. In the axis where the influence of the gravitational acceleration is strong, the value of the vertical gravitational acceleration data is increased because the value of the gravitational acceleration data is multiplied by a larger value of the gravitational acceleration dispersion ratio.

  The vertical direction emphasis synthesized acceleration data calculation unit 48 includes the X-axis direction vertical deviation gravity acceleration data, the Y-axis direction vertical deviation gravity acceleration data, and the Z-axis direction obtained by the vertical deviation gravity acceleration data calculation unit 47, respectively. Synthesize the vertical deviation gravity acceleration data. Originally, when synthesizing acceleration data, it is necessary to calculate the square root of the sum of squared values of vertical deviation gravity acceleration data in the direction of each axis. However, here, the synthesized acceleration data (vertically emphasized synthesized acceleration data) is obtained by simply adding the values of the vertical deviation gravity acceleration data in the respective axial directions. The reason is that it has the advantage of reducing the load of the vertical-weighted composite acceleration data calculation process, the advantage of not losing the positive / negative polarity of the acceleration data, and sufficiently characteristic data can be obtained. is there.

  The synthetic acceleration data storage unit 49 is configured by, for example, a ring buffer. The combined acceleration data storage unit 49 stores the vertical direction emphasized combined acceleration data obtained by the vertical direction emphasized combined acceleration data calculation unit 48. The smoothing unit 50 reads a predetermined number (for example, four) of vertically-emphasized combined acceleration data from the combined acceleration data storage unit 49 and calculates a moving average value thereof. Here, by obtaining the moving average value of the vertical direction enhanced composite acceleration data for a relatively short time, the vertical direction enhanced combined acceleration data can be smoothed by removing noise and slight fluctuations. The output data of the smoothing unit 50 is sent to the upper chord peak value detection unit 25, the lower chord peak value detection unit 26, and the flag control unit 29 via an output terminal 54.

(Body motion detection procedure)
FIG. 4 and FIG. 5 are flowcharts showing the body motion detection processing procedure by the body motion detection method of the body motion detection device according to the present invention. As shown in FIG. 4, when the body motion detection device 11 is turned on and the body motion detection process is started, first, in each of the X axis direction, the Y axis direction, and the Z axis direction, the acceleration sensor 12, 13 and 14 and the analog / digital conversion units 21, 22, and 23 acquire acceleration data (step S1). Then, the acceleration data in the respective axial directions are stored in the X-axis, Y-axis, and Z-axis acceleration data storage units 41, 42, and 43 (step S2). The processing so far is repeated until a predetermined number (for example, eight) of acceleration data is stored in the acceleration data storage units 41, 42, and 43 of the respective axes.

  When a predetermined number of acceleration data is stored in the acceleration data storage units 41, 42, and 43 for each axis, gravity acceleration is calculated by the gravity acceleration calculation unit 44 for each axis direction (step S3). Next, for each axial direction, the gravitational acceleration dispersion ratio determining unit 45 determines the gravitational acceleration dispersion ratio (step S4). Further, for each axial direction, the gravity removal acceleration data calculation unit 46 calculates the gravity removal acceleration data (step S5). Step S4 may be performed after step S5 is performed. Next, vertical deviation gravity acceleration data is calculated by the vertical deviation gravity acceleration data calculation unit 47 for each axial direction (step S6).

  Next, the vertical direction emphasized synthesized acceleration data is calculated by synthesizing the vertical deviation gravity acceleration data in the respective axis directions by the vertical direction emphasized synthesized acceleration data calculating unit 48 (step S7). Then, the vertical acceleration emphasizing synthetic acceleration data is stored in the synthetic acceleration data storage unit 49 (step S8). The processing up to this point is repeated until a predetermined number (for example, four) of vertical direction emphasized combined acceleration data is stored in the combined acceleration data storage unit 49.

  When the predetermined number of vertically emphasized combined acceleration data is stored in the combined acceleration data storage unit 49, the smoothing unit 50 smoothes the vertically emphasized combined acceleration data (step S9). Next, the upper chord peak value detecting unit 25 and the lower chord peak value detecting unit 26 detect the upper chord peak value and the lower chord peak value of the vertically emphasized synthesized acceleration data (step S10). Next, the peak difference detection unit 27 calculates the difference between the upper chord peak value and the lower chord peak value (step S11). Next, the threshold value determination unit 28 compares the difference between the upper chord peak value and the lower chord peak value with the threshold value. If the difference is larger than the threshold value, it is determined that body movement has been detected, and if the difference is smaller, it is determined that body movement has not been detected (step S12).

  On / off of the body motion detection flag is controlled based on the determination result of the threshold determination unit 28 (step S13). When it is determined that the body motion is detected, the flag control unit 29 turns on the body motion detection flag and then switches it off. If it is determined that no body movement has been detected, the body movement detection flag remains off. The series of body motion detection processes described above is repeated until the power of the body motion detection device 11 is turned off. Gravity acceleration calculation processing in step S3, gravitational acceleration dispersion ratio determination processing in step S4, removal gravity acceleration data calculation processing in step S5, vertical deviation gravity acceleration data calculation processing in step S6, step S7 The contents of the vertical direction enhanced composite acceleration data calculation process, the smoothing process in step S9, and the peak value detection process in step S10 are as described in the configuration of each functional unit.

(Example 1 of timing for turning on the body motion detection flag)
FIG. 6 is a waveform diagram showing a first example of timing for turning on the body motion detection flag. In FIG. 6, the vertical direction emphasized combined acceleration data output from the acceleration acquisition unit 24 is shown as a waveform, but actually, the vertical direction emphasized combined acceleration data is not continuous data but is predetermined data. It is discrete data sampled at a period (the same applies to FIGS. 7 and 8). Further, in FIG. 6, a triangle mark indicates the timing when the body motion detection flag is turned on, and the numbers (1, 2, 3, 4, 5) below the body motion count indicate the body motion count (FIGS. The same applies to

  In the example shown in FIG. 6, the peak difference detection unit 27 calculates the difference between the lower chord peak value and the upper chord peak value immediately after that. In this example, after it is determined that the body motion is detected by the threshold value determination unit 28, the body motion detection is performed when the value of the vertical direction weighted combined acceleration data output from the acceleration acquisition unit 24 becomes zero for the first time. The flag is turned on. This is because the vicinity of the upper chord peak value and the lower chord peak value is easily affected by noise or the like, so that the body motion detection flag is turned on while avoiding this.

  Specifically, the difference between the first lower chord peak 61 and the first upper chord peak 62, the difference between the third lower chord peak 65 and the third upper chord peak 66, the fourth lower chord peak 67 and the fourth upper chord peak 68. , The difference between the sixth lower chord peak 71 and the sixth upper chord peak 72, and the difference between the seventh lower chord peak 73 and the seventh upper chord peak 74 are larger than the threshold. Therefore, after the first cosine peak 62, the third cosine peak 66, the fourth cosine peak 68, the sixth cosine peak 72, and the seventh cosine peak 74, the value of the vertical enhancement composite acceleration data is the first time. When it becomes zero, the body motion detection flag is turned on and the body motion is counted. On the other hand, since the difference between the second lower chord peak 63 and the second upper chord peak 64 and the difference between the fifth lower chord peak 69 and the fifth upper chord peak 70 are smaller than the threshold value, the body motion detection flag remains off. The body movement is not counted and is a value as it is.

(Timing example 2 for turning on the body motion detection flag)
FIG. 7 is a waveform diagram showing a second example of timing for turning on the body motion detection flag. In the example shown in FIG. 7, the peak difference detection unit 27 calculates a difference between the lower chord peak value and the immediately following upper chord peak value, and when the threshold determination unit 28 determines that body movement such as walking is detected, Immediately, the body motion detection flag is turned on. Instead of the first timing example described above, this second timing example may be used.

(Timing example 3 for turning on the body motion detection flag)
FIG. 8 is a waveform diagram showing a third example of timing for turning on the body motion detection flag. In the example shown in FIG. 8, the peak difference detection unit 27 calculates the difference between the upper chord peak value and the lower chord peak value immediately thereafter, and after the threshold determination unit 28 determines that the body movement has been detected, the acceleration acquisition unit 24. The body motion detection flag is turned on when the value of the vertical direction enhanced composite acceleration data output from is zero for the first time. As in the second timing example described above, the body motion detection flag may be turned on immediately when the threshold determination unit 28 determines that the body motion has been detected. Instead of the first or second timing example described above, this third timing example may be used.

  As described above, according to the embodiment, the influence of the subject's irregular movement, noise, and the like can be eliminated by comparing the variation amount of the acceleration with the threshold value. Therefore, it is possible to prevent erroneous recognition that the body movement is not actually a body movement, or that the body movement is actually a body movement but not the body movement. That is, body movement can be detected accurately. Accordingly, an accurate body motion count can be obtained. As described above, the present invention is not limited to the above-described embodiment, and various modifications can be made.

  As described above, the body motion detection method according to the present invention is useful for a body motion detection device.

It is a block diagram which shows the hardware constitutions of the body movement detection apparatus concerning this invention. It is a block diagram which shows the functional structure of the processing apparatus of the body movement detection apparatus concerning this invention. It is a block diagram which shows the functional structure of the acceleration acquisition part of the body movement detection apparatus concerning this invention. It is a flowchart (the 1) which shows the body motion detection process sequence by the body motion detection method of the body motion detection apparatus concerning this invention. It is a flowchart (the 2) which shows the body motion detection process sequence by the body motion detection method of the body motion detection apparatus concerning this invention. It is a wave form diagram which shows the 1st example of the timing which turns on a body movement detection flag. It is a wave form diagram which shows the 2nd example of the timing which turns on a body movement detection flag. It is a wave form diagram which shows the 3rd example of the timing which turns on a body movement detection flag. It is a wave form diagram which shows the change of the detected value of the acceleration in the conventional body motion detection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Body motion detection apparatus 12, 13, 14 Acceleration sensor 24 Acceleration acquisition part 25, 26 Peak value detection part 27 Peak difference detection part 28 Threshold determination part

Claims (9)

In the body motion detection device that determines the detection of body motion based on the magnitude of acceleration output from the acceleration sensor,
Detection of body movement is detected based on the lower chord peak value at which the magnitude of acceleration switches from a decreasing trend to an increasing trend and the upper chord peak value at which the magnitude of acceleration switches from a decreasing trend to a decreasing trend. A body motion detection device characterized by the above.   The body motion detection device according to claim 1, wherein a difference between the lower chord peak value and the upper chord peak value is calculated, and the detection of body motion is determined by comparing the difference with a threshold value.   The body motion detection device according to claim 2, wherein the difference is calculated from the upper chord peak value immediately before or after the lower chord peak value.   The body motion detection device according to claim 2, wherein it is determined that body motion is detected when the difference is greater than the threshold value.   After determining that the body movement has been detected, the body movement is counted when the magnitude of the acceleration crosses a predetermined value for the first time or decreases for the first time. The body movement detection device according to any one of claims 1 to 4.   The body movement detection device according to claim 1, wherein the body movement is counted when it is determined that the body movement is detected.   The body motion according to any one of claims 1 to 6, wherein the acceleration sensor detects accelerations in three different directions and acquires the magnitude of the acceleration based on the accelerations in the three directions. Detection device.   The body motion detection device according to claim 7, wherein the magnitude of the acceleration is a magnitude obtained by subtracting gravitational acceleration from the detected acceleration.   The body motion detection device according to claim 8, wherein, for each of the three directions, an average value of a plurality of continuous detection values of the acceleration is regarded as the gravitational acceleration.

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