Activity amount calculation device and activity amount calculation method

Abstract

An activity amount calculation device and an activity amount calculation method are provided that can calculate an activity amount in a non-contact manner. [Solution] The activity amount calculation device 1 is roughly configured to include a communication unit 20 that periodically acquires a point cloud 43, which is a collection of points 44 that associate position information with the intensity p of reflected waves 41 based on the reflection of electromagnetic waves 40 output toward a detection object 9, from a 3D sensor 4 as a detection device; a difference point calculation unit 10 that compares a previous point cloud 45 and a current point cloud 46 that are acquired consecutively to calculate difference points 451; and an activity amount calculation unit 14 that calculates the sum D of the intensities p of the calculated difference points 451 as the activity amount P of the detection object 9.

Description

[Technical Field]

[0001] The present invention relates to an activity amount calculation device and an activity amount calculation method. [Background technology]

[0002] As a conventional technique, a system equipped with a motion tracker that is worn on a person's wrist, arm, leg, or chest and records the amount of activity of the person is known (see, for example, Patent Document 1).

[0003] The system can use the amount of activity recorded to determine the time duration of the rest period. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2018-507050 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional systems have the problem that they cannot obtain activity data unless the user wears a motion tracker.

[0006] Therefore, an object of the present invention is to provide an activity amount calculation device and an activity amount calculation method that can acquire an activity amount in a non-contact manner. [Means for solving the problem]

[0007] One aspect of the present invention provides an activity amount calculation device including: an acquisition unit that periodically acquires a point cloud, which is a collection of points having position information and the intensity of reflected waves associated with each other, from a detection device based on the reflection of electromagnetic waves output toward a detection target; a difference point calculation unit that compares a previous point cloud and a current point cloud that are acquired consecutively to calculate difference points; and an activity amount calculation unit that calculates the sum of the intensities of the calculated difference points as the activity amount of the detection target.

[0008] Another aspect of the present invention provides a method for calculating an amount of activity, which periodically acquires a point cloud from a detection device, which is a collection of points having position information associated with the intensity of the reflected wave based on the reflection of an electromagnetic wave output toward a detection target, compares the previous point cloud and the current point cloud acquired in succession to calculate difference points, and calculates the sum of the intensities of the calculated difference points as the amount of activity of the detection target. [Effects of the Invention]

[0009] According to the present invention, the amount of activity can be acquired in a non-contact manner. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1(a) is an example of a block diagram of an activity amount calculation device according to an embodiment, and FIG. 1(b) is a diagram showing an example of a 3D sensor and a detection area. [Figure 2] FIG. 2(a) is a diagram showing an example of a previous point cloud according to the embodiment, and FIG. 2(b) is a diagram showing an example of a current point cloud. [Figure 3] FIG. 3(a) is a diagram showing an example of a current time point at which it is assumed that an activity has occurred according to the embodiment, and FIG. 3(b) is a diagram showing an example of a current time point at which it is assumed that no activity has occurred. [Figure 4] FIG. 4 is a diagram illustrating an example of a calculation region of the activity amount calculating device according to the embodiment. [Figure 5] FIG. 5(a) is a diagram showing an example of the amount of activity in a sitting position according to the embodiment, and FIG. 5(b) is a diagram showing an example of the amount of activity in a lying position. [Figure 6] FIG. 6 is a diagram showing a room in which the 3D sensors according to the first to fourth embodiments are arranged. [Figure 7] FIG. 7(a) is a graph of activity amounts according to Example 1, FIG. 7(b) is a graph showing the AW2 formula substitution results, and FIG. 7(c) is a graph showing the Cole formula substitution results. [Figure 8]FIG. 8(a) is a graph of activity amounts according to Example 2, FIG. 8(b) is a graph showing the AW2 formula substitution result, and FIG. 8(c) is a graph showing the Cole formula substitution result. [Figure 9] FIG. 9(a) is a graph of activity amounts according to Example 3, FIG. 9(b) is a graph showing the AW2 formula substitution results, and FIG. 9(c) is a graph showing the Cole formula substitution results. [Figure 10] FIG. 10(a) is a graph of activity amounts according to Example 4, FIG. 10(b) is a graph showing the AW2 formula substitution results, and FIG. 10(c) is a graph showing the Cole formula substitution results. [Figure 11] FIG. 11 is a flowchart showing an example of the operation of the activity amount calculation device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Summary of the embodiment) An activity amount calculation device according to an embodiment is generally configured to include an acquisition unit that periodically acquires a point cloud, which is a collection of points having position information associated with the intensity of reflected waves based on the reflection of electromagnetic waves output toward a detection target, from the detection device; a difference point calculation unit that compares a previous point cloud and a current point cloud that are acquired consecutively to calculate difference points; and an activity amount calculation unit that calculates the sum of the intensities of the calculated difference points as the activity amount of the detection target.

[0012] Another embodiment of the activity amount calculation method includes periodically acquiring a point cloud, which is a collection of points having position information and the intensity of the reflected wave associated with each other, from a detection device based on the reflection of electromagnetic waves output toward a detection target, comparing the previous point cloud and the current point cloud acquired in succession to calculate difference points, and calculating the sum of the intensities of the calculated difference points as the activity amount of the detection target.

[0013] This activity amount calculation device and activity amount calculation method can obtain activity amounts non-contactly without attaching a detection device to the detection target, and therefore can reduce the risk of activity amounts not being obtained due to forgetting to attach the device, compared to when activity amounts cannot be obtained unless the device is attached.

[0014] [Embodiment Mode] (Outline of activity amount calculation device 1) FIG. 1(a) is an example of a block diagram of an activity calculation device according to an embodiment, and FIG. 1(b) is a diagram illustrating an example of a 3D sensor and a detection area. FIG. 2(a) is a diagram illustrating an example of a previous point cloud according to an embodiment, and FIG. 2(b) is a diagram illustrating an example of a current point cloud. FIG. 3(a) is a diagram illustrating an example of a current point at which activity is considered to have occurred according to an embodiment, and FIG. 3(b) is a diagram illustrating an example of a current point at which activity is considered to have occurred according to an embodiment. FIG. 4 is a diagram illustrating an example of a calculation area of ​​an activity calculation device according to an embodiment. In FIGS. 2(a) and 2(b), the X-axis is a coordinate axis with the 3D sensor 4 as the origin, with the left side being positive and the right side being negative. The Y-axis is a positive coordinate axis with the point where the Y-axis intersects with the Z-axis as the origin, and the Z-axis is a positive coordinate axis with the point where the Y-axis intersects with the Y-axis as the origin. Points 44 constituting the point cloud 43 have coordinate values ​​in an XYZ coordinate system as position information. Furthermore, the dark points 44 shown in FIGS. 2(a) and 2(b) have a low intensity p of the reflected wave 41, and the light points 44 have a high intensity p.

[0015] In the drawings relating to the embodiments described below, the ratios and shapes between figures may differ from the actual ratios and shapes. In addition, arrows in Fig. 1 indicate the flow of main information. Below, an overview of the activity amount calculation device 1 will be first described.

[0016] As shown in FIGS. 1(a) to 2(b), the activity amount calculation device 1 is generally configured to include a communication unit 20 as an acquisition unit that periodically acquires a point cloud 43, which is a collection of points 44 having position information and intensity p of reflected waves 41 associated with each other, from a 3D sensor 4 as a detection device, based on the reflection of electromagnetic waves 40 outputted toward a detection target 9; a difference point calculation unit 10 that compares a previous point cloud 45 and a current point cloud 46 that are successively acquired to calculate difference points 451, which will be described later; and an activity amount calculation unit 14 that calculates a sum D of the intensities p of the calculated difference points 451 as the activity amount P of the detection target 9.

[0017] The detection target 9 in this embodiment is, for example, a person as shown in FIG. 1(b), but is not limited to this. The 3D sensor 4 is, for example, a millimeter-wave radar or LiDAR (Light Detection and Ranging). The 3D sensor 4 in this embodiment is, for example, a millimeter-wave radar that uses millimeter waves as the electromagnetic waves 40, but is not limited to this. These millimeter waves are, for example, electromagnetic waves with a wavelength of 1 to 10 mm. The 3D sensor 4 in this embodiment is, for example, placed at a height of 1.8 m from the floor, but is not limited to this.

[0018] 1(b), the 3D sensor 4 generates and outputs point cloud information S1, which is information on one period of point cloud 43 in the detection area 42. This point cloud information S1 is information in which coordinate values ​​indicating position information in an XYZ coordinate system are associated with intensities p at those coordinate values. Note that the 3D sensor 4 outputs the point cloud information S1 at 0.1 second intervals, for example, but is not limited to this.

[0019] As shown in Figures 2(a) to 3(b), the difference point calculation unit 10 sets a difference region 100 centered on the previous point 450 of the previous point cloud 45, and if the current point 460 is included in the difference region 100 in the current point cloud 46, the current point 460 is set as the difference point 451, and if the current point 460 is not included in the difference region 100, the difference point calculation unit 10 is configured not to calculate the difference point 451.

[0020] The activity amount calculation unit 14 has a threshold value 140, and when the number of calculated difference points 451 is equal to or greater than the threshold value 140, calculates a sum D of the intensities p of the difference points 451, and when the number of difference points 451 is less than the threshold value 140, sets the sum D of the intensities p of the difference points 451 to zero.

[0021] The activity amount calculation device 1 includes a center calculation unit 12 that calculates the center 120 of the previous point cloud 45. As shown in FIG. 4 , the activity amount calculation unit 14 calculates a sum D of intensities p of difference points 451 in a calculation region 141 including the calculated center 120 as the activity amount P of the detection object 9.

[0022] The activity amount calculation device 1 performs a smoothing process on the plurality of activity amounts P calculated over a plurality of periods, and then corrects the intensity p of the reflected wave 41 according to the distance from the 3D sensor 4 to obtain a corrected activity amount P. a is calculated, and then the normalized activity amount P b The correction unit 16 calculates the

[0023] The activity amount calculation device 1 further includes a storage unit 18 and a control unit 22, as shown in FIG.

[0024] The storage unit 18 is, for example, but not limited to, a semiconductor memory. The storage unit 18 stores accumulated information 180 in which a plurality of pieces of point cloud information S1 are accumulated in time series.

[0025] (Configuration of difference point calculation unit 10) The difference point calculation unit 10 reads the previous point cloud 45 from the accumulated information 180 stored in the storage unit 18, and calculates the difference points 451 between the previous point cloud 45 and the current point cloud 46 acquired via the communication unit 20. As an example, the difference point calculation unit 10 reads the previous point cloud information S2 from the storage unit 18 as the information on the previous point cloud 45, and acquires the point cloud information S1 via the communication unit 20 as the information on the current point cloud 46.

[0026] As a modified example, the current point cloud 46 may be stored together with the previous point cloud 45, for example, as accumulated information 180. In other words, all of the point cloud information S1 output from the 3D sensor 4 is stored as accumulated information 180. The difference point calculation unit 10 reads out the consecutive previous point cloud 45 and current point cloud 46 from this accumulated information 180 in order to calculate the difference points 451. The difference point calculation unit 10 may also calculate the difference points 451 of any consecutive point clouds 43 stored in the accumulated information 180.

[0027] 3(a) and 3(b), the difference point calculation unit 10 sets a difference region 100 for each point (previous point 450) in the previous point cloud 45. As an example, this difference region 100 is a cubic region with a side length of 100 mm centered at the previous point 450, but is not limited to this.

[0028] When a detection target is active, not all points in the point cloud move significantly. For example, if the detection target moves only its hands, the points in the point cloud other than the hands may not move at all. In particular, when calculating the amount of activity of the detection target based on the movement of the center and determining whether or not the target is active based on this amount of activity, even if part of the body moves, the movement of the center is small, making it difficult to determine that the target is active.

[0029] However, as shown in FIGS. 3( a) and 3(b), the difference point calculation unit 10 of this embodiment distinguishes between the presence and absence of activity based on whether the current point 460 of the current point cloud 46 is inside or outside the differential region 100. The difference point calculation unit 10 calculates the difference point 451 only when the current point 460 is outside the differential region 100. Note that, for example, when multiple current points 460 exist in the differential region 100, the difference point calculation unit 10 calculates the closest current point 460 as the difference point 451, but this is not limited to this. Also, for example, when multiple current points 460 exist in the differential region 100 that are the same distance from the previous point 450, the difference point calculation unit 10 extracts the current point 460 with the greatest intensity p and sets it as the difference point 451, but this is not limited to this.

[0030] The difference point calculation unit 10 generates difference point information S3, which is information on the difference point 451, and outputs it to the control unit 22.

[0031] (Configuration of center calculation unit 12) The center calculation unit 12 calculates the center 120 based on the acquired previous point cloud information S2. The center 120 is found, for example, from the coordinate values ​​of the previous point 450 of the previous point cloud 45, but may be calculated by weighting according to the distance from the 3D sensor 4, or may be the center of gravity, and is not limited to these. The center calculation unit 12 generates center information S4 including information on the coordinate values ​​of the calculated center 120 and outputs it to the activity amount calculation unit 14.

[0032] (Configuration of activity amount calculation unit 14) The activity amount calculation section 14 sets a calculation region 141 including the center 120 based on the acquired center information S4. As an example, this calculation region 141 is an area inside a sphere with a radius R, as shown in FIG. 4. This radius R is, for example, 1.0 to 2.0 m. In this embodiment, the radius R is, for example, 1.5 m.

[0033] The activity amount calculation section 14 compares the number of difference points 451 included in the calculation region 141 with the threshold value 140 based on the acquired difference point information S3.

[0034] When the number of difference points 451 is equal to or greater than the threshold value 140, the activity amount calculation unit 14 calculates the sum D of the intensities p of the difference points 451. Note that the threshold value 140 may be configured to vary depending on the distance from the 3D sensor 4. In this case, the threshold value 140 decreases as the distance from the 3D sensor 4 increases.

[0035] The activity amount calculation unit 14 sets the calculated sum D as the activity amount P. The activity amount calculation unit 14 generates activity amount information S5 including information on the activity amount P and outputs the activity amount information S5 to the correction unit 16. Note that the activity amount information S5 may be stored in the storage unit 18 as accumulated information 180.

[0036] (Configuration of correction unit 16) As an example, the correction unit 16 corrects the activity amount P, which is the calculated sum D, to an actigraph-equivalent value or a most recent difference-equivalent value so that it can be output to the connected electronic device 7. For example, by correcting the activity amount P to an actigraph-equivalent value, the electronic device 7 can process the corrected activity amount P in the same way as when connected to a device that outputs an actigraph. Furthermore, by correcting the activity amount P to a most recent difference-equivalent value, the electronic device 7 can process the corrected activity amount P in the same way as when connected to a device that processes most recent differences. The electronic device 7 is, for example, a personal computer, a multi-function mobile phone, or a tablet terminal.

[0037] The actigraph-equivalent value is calculated as an integrated value for each communication interval, and the most recent difference-equivalent value is calculated as an instantaneous value for each communication interval.

[0038] The correction unit 16 performs a moving average process to smooth the plurality of activity amounts P acquired during the communication interval. Next, the correction unit 16 performs intensity correction according to the distance from the 3D sensor 4 to the center 120 of each activity amount P, and obtains the corrected activity amount P a This intensity correction is performed to compensate for the low intensity p detected by the 3D sensor 4 when the distance is large. In other words, the intensity correction is performed to increase the amount of activity P according to the distance.

[0039] Next, the correction unit 16 performs normalization processing according to the output destination. That is, the corrected amount of activity P a For example, if the value is equivalent to an actigraph, it is normalized to a scale of 0 to 10, and the normalized activity amount P b The corrected activity amount P a For example, if the value is equivalent to the most recent difference, it is normalized to a scale of 0 to 100 and the normalized activity amount P b The corrector 16 corrects the normalized amount of activity P b The corrected activity amount information S6 including the above information is generated and output to the electronic device 7 via the communication unit 20.

[0040] Fig. 5(a) is a diagram showing an example of the amount of activity in a sitting position according to an embodiment, and Fig. 5(b) is a diagram showing an example of the amount of activity in a lying position. In Fig. 5(a) and Fig. 5(b), the horizontal axis represents time, and the vertical axis represents the amount of activity P. Fig. 5(a) shows the amount of activity P in four states in a sitting position: "standing still," "twisting body left and right," "raising and lowering hands," and "raising and lowering legs." Fig. 5(b) shows the amount of activity P in four states in a lying position: "standing still," "turning over," "raising and lowering hands," and "raising and lowering legs."

[0041] When the object to be detected 9 is in a sitting position, for example, in the states of "twisting the body left and right," "raising and lowering the hands," and "raising and lowering the legs," the center position is almost the same as the center position in the "stationary" state.

[0042] Furthermore, when the detection target 9 is in a lying position, for example, in the states of "raising and lowering hands" and "raising and lowering legs," the center position is almost the same as the center position in the "resting" state.

[0043] As shown in FIGS. 5(a) and 5(b), the activity amount calculation device 1 of this embodiment shows large fluctuations in the calculated activity amount P in both states, so that it is possible to easily detect the presence or absence of activity in the sitting and lying positions, where the activity amount P is more difficult to detect than in the standing position.

[0044] (Configuration of control unit 22) The control unit 22 is a microcomputer including, for example, a CPU (Central Processing Unit) that performs calculations and processing on acquired data in accordance with a stored program 220, and semiconductor memories such as a RAM (Random Access Memory) and a ROM (Read Only Memory). The ROM stores, for example, the program 220 that enables the control unit 22 to operate. The RAM is used, for example, as a storage area for temporarily storing calculation results. The control unit 22 also has a means for generating a clock signal therein and operates based on this clock signal.

[0045] The control unit 22 comprehensively controls the difference point calculation unit 10, the center calculation unit 12, the activity amount calculation unit 14, the correction unit 16, the storage unit 18, and the communication unit 20. At least a part of the difference point calculation unit 10, the center calculation unit 12, the activity amount calculation unit 14, and the correction unit 16 may be realized by a program 220 executed by the control unit 22, or may be realized by hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array), or may be realized by a combination of both.

[0046] (Regarding Examples 1 to 4) FIG. 6 is a diagram showing a room in which 3D sensors according to Examples 1 to 4 are arranged. FIG. 7(a) is a graph of activity quantity values ​​according to Example 1, FIG. 7(b) is a graph showing the AW2 formula substitution result, and FIG. 7(c) is a graph showing the Cole formula substitution result. FIG. 8(a) is a graph of activity quantity values ​​according to Example 2, FIG. 8(b) is a graph showing the AW2 formula substitution result, and FIG. 8(c) is a graph showing the Cole formula substitution result. FIG. 9(a) is a graph of activity quantity values ​​according to Example 3, FIG. 9(b) is a graph showing the AW2 formula substitution result, and FIG. 9(c) is a graph showing the Cole formula substitution result. FIG. 10(a) is a graph of activity quantity values ​​according to Example 4, FIG. 10(b) is a graph showing the AW2 formula substitution result, and FIG. 10(c) is a graph showing the Cole formula substitution result.

[0047] The actigraph 5 used for detection is a micro motion logger watch-type actigraph attached to the left hand of the subject 9. The activity amount P is a ZCM (Zero Crossing Mode) value obtained from the actigraph 5. The activity amount P of the 3D sensor 4 is converted into an actigraph-equivalent value so that it can be compared with the activity amount P of the actigraph 5.

[0048] In Figures 7(a), 8(a), 9(a), and 10(a), the horizontal axis represents time and the vertical axis represents the amount of activity P. In Figures 7(b), 8(b), 9(b), and 10(b), the horizontal axis represents time and the vertical axis represents the AW2 analysis value. In Figures 7(c), 8(c), 9(c), and 10(c), the horizontal axis represents time and the vertical axis represents the Cole analysis value. In Figures 7(a) to 10(c), the solid lines are graphs for the 3D sensor 4, and the dotted lines are graphs for the actigraph 5.

[0049] Examples 1 to 4 relating to detection of activity amount during sleep are described below. Examples 1 to 4 were performed in a room 6 as shown in FIG. 6. The room 6 had a width H of 2600 mm and a depth of 4500 mm. The 3D sensor 4 was installed on a wall 60 on the left side of the page in FIG. 6 at a height of 1.8 m. The detection area 42 of the 3D sensor 4 was set to X = ±1.5 m, Y = 0.3 to 2.5 m, and Z = −0.1 to 2.0 m. The detection target 9 was lying in a bed 62 on the side of a wall 61 facing the wall 60. The detection target 9 was 170 cm tall and weighed 63 kg. The point cloud information S1 was acquired every 0.5 seconds, and corrected activity amount information S6 was output to the electronic device 7 at 1-second intervals. The point cloud information S1 was acquired over a period spanning four consecutive days, from night to morning on days A to D. The activity amount P detected in Example 1 is the activity amount on day A, the activity amount P detected in Example 2 is the activity amount on day B, the activity amount P detected in Example 3 is the activity amount on day C, and the activity amount P detected in Example 4 is the activity amount measured on day D.

[0050] The normalized cross-correlation showed the similarity between the 3D sensor 4 and the actigraph 5, with a high correlation being obtained on days A to D.

[0051] The average activity values ​​obtained on days A to D were similar between the 3D sensor 4 and the actigraph 5.

[0052] The maximum activity value obtained for 3D sensor 4 was higher than that of actigraph 5 on days A to D. This is because actigraph 5 is attached to the left hand, so even if the body is moving, the measured activity amount is small if the left hand does not move, whereas 3D sensor 4 measures the total activity amount.

[0053] The percentage of activity level 0 was similar between 3D sensor 4 and actigraph 5 on days A to D.

[0054] The sleep rate using the AW2 method was similar between the 3D sensor 4 and the actigraph 5 on days A to D. The sleep rate using the AW2 method was calculated by dividing the sleep assessment time by the total sleep time.

[0055] The Cole sleep rate showed similar values ​​for the 3D sensor 4 and the actigraph 5 on days A to D. The Cole sleep rate was calculated by applying the formula to the amount of activity measured at one-minute intervals.

[0056] Regarding Examples 1 to 4 In Examples 1 to 4, as shown in Figures 7(a) to 10(c), it was confirmed that the 3D sensor 4 also reacted when the actigraph 5 reacted. Furthermore, the 3D sensor 4 detects not only the movement of the left hand but also changes in the movement of the entire body, and therefore has higher accuracy than the actigraph 5. Therefore, the detection results of the 3D sensor 4 are higher than the detection results of the actigraph 5 due to their higher accuracy.

[0057] An example of the operation of the activity amount calculation device 1 according to this embodiment will be described with reference to the flowchart of FIG.

[0058] (operation) The communication unit 20 of the activity amount calculation device 1 acquires point cloud information S1 (Step 1).

[0059] The difference point calculation unit 10 calculates difference points 451 from the previous point cloud 45 and the current point cloud 46 that are successively acquired based on the acquired point cloud information S1 (Step 2).

[0060] The center calculation unit 12 calculates the center 120 from the previous point cloud 45 based on the acquired previous point cloud information S2 (Step 3).

[0061] The activity amount calculation unit 14 sets a calculation region 141 including the center 120 based on the acquired center information S4, and compares the number of difference points 451 included in the calculation region 141 with a threshold value 140. If the number of difference points 451 is equal to or greater than the threshold value 140 (Step 4: Yes), the activity amount calculation unit 14 calculates the sum D of the intensities p of the difference points 451 as the activity amount P (Step 5), and ends the operation of calculating the activity amount P.

[0062] Here, in step 4, if the number of difference points 451 is smaller than the threshold value 140 (Step 4: No), the activity amount calculation section 14 stops calculating the activity amount P (Step 6) and ends the operation of calculating the activity amount P.

[0063] (Effects of the embodiment) The activity amount calculation device 1 according to this embodiment can acquire the activity amount P in a non-contact manner without attaching an actigraph or the like to the detection target 9, and therefore can acquire the activity amount P continuously compared to when the activity amount P cannot be acquired without attaching an actigraph or the like.

[0064] The activity amount calculation device 1 can easily obtain the activity amount P even for slight activity with little movement of the center or center of gravity, and therefore can improve the accuracy of monitoring elderly people and children using the detected activity amount P compared to when the activity amount P cannot be obtained. Furthermore, the activity amount calculation device 1 is suitable for applications such as obtaining the activity amount P of a child restrained in a child seat to prevent the child from being left behind in a vehicle.

[0065] The activity amount calculation device 1 can continuously acquire activity amount P in a sitting or lying position, which is difficult to acquire, and therefore, by using the continuously acquired activity amount P, the estimation accuracy of devices that estimate sleep quality can be improved compared to when activity amount cannot be continuously acquired due to forgetting to wear the device, etc.

[0066] As another embodiment, the present invention may be provided as a program for executing an activity amount calculation method, which includes periodically acquiring a point cloud 43 from a detection device, which is a collection of points 44 each having position information associated with an intensity p of a reflected wave 41 based on the reflection of an electromagnetic wave 40 outputted toward a detection target 9, comparing a previous point cloud 45 and a current point cloud 46 acquired in succession to calculate difference points 451, and calculating a sum D of the intensities p of the calculated difference points 451 as the activity amount P of the detection target 9, or as a computer-readable recording medium having this program recorded thereon.

[0067] Although the embodiment of the present invention has been described above, this embodiment is merely an example and does not limit the scope of the invention as claimed. This novel embodiment can be embodied in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the spirit of the present invention. Furthermore, not all combinations of features described in this embodiment are necessarily essential to the means for solving the problems of the invention. Furthermore, this embodiment is included within the scope and spirit of the invention, and is included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0068] 1...Activity amount calculation device, 4...3D sensor, 5...Actigraph, 6...Room, 7...Electronic device, 9...Detection target, 10...Difference point calculation unit, 12...Center calculation unit, 14...Activity amount calculation unit, 16...Correction unit, 18...Memory unit, 20...Communication unit, 22...Control unit, 40...Electromagnetic wave, 41...Reflected wave, 42...Detection area, 43...Point cloud, 44...Point, 45...Previous point cloud, 46...Current point cloud, 60, 61...Wall, 62...Bed, 100...Difference area, 120...Center, 140...Threshold, 141...Calculation area, 180...Stored information, 220...Program, 450...Previous point, 451...Difference point, 460...Current point

Claims

1. an acquisition unit that periodically acquires a point cloud from the detection device, the point cloud being a set of points having position information associated with the intensity of the reflected wave based on the reflection of the electromagnetic wave output toward the detection target; a difference point calculation unit that compares the previous point cloud and the current point cloud that are successively acquired to calculate difference points; an activity amount calculation unit that calculates a sum of the intensities of the calculated difference points as an activity amount of the detection target; An activity calculation device comprising:

2. the difference point calculation unit sets a difference region centered on the previous point of the previous point cloud, and when a current point is included in the difference region in the current point cloud, the current point is set as the difference point, and when the current point is not included in the difference region, the difference point calculation unit does not calculate the difference point. The activity calculation device according to claim 1 .

3. the activity amount calculation unit has a threshold value, and when the calculated number of difference points is equal to or greater than the threshold value, calculates a sum of the intensities of the difference points, and when the number of difference points is smaller than the threshold value, sets the sum of the intensities of the difference points to zero. The activity calculation device according to claim 2 .

4. a center calculation unit that calculates the center of the previous point cloud; the activity amount calculation unit calculates a sum of the intensities of the difference points within a calculation region including the calculated center as the activity amount of the detection object; The activity calculation device according to claim 3 .

5. A correction unit is provided which performs a smoothing process on the plurality of activity amounts calculated over a plurality of periods, corrects the intensity of the reflected wave according to a distance from the detection device to calculate a corrected activity amount, and further calculates a normalized activity amount based on a normalization process according to an output destination. The activity calculation device according to claim 4 .

6. periodically acquiring, from the detection device, a point cloud, which is a set of points having position information and the intensity of the reflected wave associated with each other, based on the reflection of the electromagnetic wave output toward the detection target; The previous point cloud and the current point cloud are compared to calculate the difference points. calculating a sum of the intensities of the calculated difference points as an activity amount of the detection target; Activity amount calculation method.

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