JP2014061174A - On-bed determination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-bed determination device reducing occurrences of a false detection and an erroneous determination.SOLUTION: An on-bed determination device 100 includes: a load sensor 11 that is disposed on a bed 2 and detects a change in the load on the bed 2; a storage section 12 that sequentially stores detection results of the load sensor 11; and an on-bed determination section 17 that, when it is determined that, based on a detection result detected at least a prescribed time earlier that is stored in the storage section 12 and a detection result of a present time, the load the prescribed time earlier decreases, determines that a person 1 is present on the bed 2.

Description

  The present invention relates to an in-bed determination apparatus that determines whether a person is present on bedding.

  Conventionally, techniques for detecting the presence of a person on bedding have been widely used. As this type of technology, there is a technology described in Patent Documents 1-3 shown below.

  The in-bed detection apparatus described in Patent Literature 1 includes a vibration sensor that detects vibration of a bedding and a biosensor that detects presence or absence of a living body on the bedding. When the amplitude of the output signal of the vibration sensor exceeds the body motion threshold, the occupancy detection device determines that the body motion state is caused by the movement of the living body on the bedding. Further, when the amplitude of the output signal of the vibration sensor is equal to or less than the body movement threshold value and the living body is detected by the living body sensor, it is determined that the user is in the bed. Furthermore, if the amplitude of the output signal of the vibration sensor is equal to or less than the body motion threshold and no living body is detected by the living body sensor, it is determined that the absence state is present.

  The state detection system described in Patent Document 2 obtains a time average value and a long-time average value from the total load value on the bed floor detected by the load detection means, and the state on the bed is based on the difference between them. It is determined whether the user is in bed or is out of bed.

JP 2007-202847 A JP 2009-118980 A

  In the technique described in Patent Document 1, small vibrations such as respiration and heartbeat are detected as a biological signal. For this reason, an expensive sensor with high detection capability is required. Further, when the detection capability is increased, it is easy to pick up external noise such as vibration due to walking, vibration due to opening / closing of a door, vibration due to an outdoor train or automobile, and the possibility of erroneous detection is increased.

  In the technique described in Patent Document 2, a long-time average value and a short-time average value are calculated. As a result, it is possible to cancel the value when the bedding such as futon is gradually increasing, but if a heavy object similar to a person is mounted on the bed, it may be mistaken for a person is there.

  In view of the above problems, an object of the present invention is to provide a presence determination device capable of reducing erroneous detection and erroneous determination.

In order to achieve the above object, the characteristic configuration of the presence determination device according to the present invention is as follows.
A load sensor disposed on the bedding and detecting a load on the bedding;
A storage unit for sequentially storing detection results of the load sensors;
There is a person on the bedding when it is determined that the load before the predetermined time is reduced based on the detection result at least a predetermined time before stored in the storage unit and the current detection result. A presence determination unit that determines that the
It is in the point equipped with.

  Here, the load on the bedding is easier to detect than the body movement caused by the pulse or breathing. For this reason, with such a characteristic configuration, it is possible to accurately determine whether or not a person is present on the bedding as compared with body movements due to pulse or respiration. Therefore, it is possible to realize a presence determination device that can reduce erroneous detection and erroneous determination. Further, since the load and body movement can be detected using an inexpensive load sensor, it can be realized with a simple structure and at a low cost.

  In addition, it is preferable that the presence determination unit determines that a person is present on the bedding when the current detection result is gradually decreased from the detection result before the predetermined time.

  A person loses weight about 100 g per hour due to the release of water vapor by sweating or breathing. Therefore, with such a configuration, it is possible to accurately determine whether or not a person is present on the bedding based on whether or not the weight is light with the same gradient as described above. .

  When the presence determination unit determines that a person is present on the bedding when the difference between the detection result before the predetermined time and the detection result at the present time is within a predetermined determination threshold value. Is preferred.

  The amount of weight loss of a sleeping person can be predicted to some extent (about 100 g per hour). Therefore, with such a configuration, if the difference between the load before a predetermined time and the current load is within the determination threshold, it can be determined that a person is present on the bedding. On the other hand, if the difference between the load before the predetermined time and the current load is larger than the determination threshold, it can be determined that no person is present on the bedding.

  In addition, it is preferable that the occupancy determination unit determine the presence of an object on the bedding except for a detection result detected in a state where there is a body movement.

  With such a configuration, even if the detection result of the load sensor deviates from the initial state due to body movement and the detection result changes relatively, whether or not there is a person on the bedding. It is possible to accurately determine whether or not.

  In addition, it is preferable that the presence determination unit determines that a person on the bedding has left the bed when the current detection result is less than a preset load value.

  When a person moves from the bedding, the load detected by the load sensor is significantly reduced. Therefore, with such a configuration, it is possible to reliably determine that a person has moved from the bedding.

  In addition, the presence determination unit has a person on the bedding when the detection result stored in the storage unit is constant for a specified time defined by a time shorter than the predetermined time. It is preferable to cancel the determination of being.

  For example, when a luggage or the like is placed on the bedding, the load is detected by a load sensor. However, in the case of luggage, there is no decrease in load due to sweating or breathing. Therefore, with such a configuration, it is possible to appropriately determine that no person is present on the bedding.

  Further, the presence determination unit is configured to determine whether the variation amount between the detection result at the present time and the detection result at a past time before the predetermined time is less than a predetermined determination threshold. It is preferable to make a preliminary determination as to whether or not a person is present.

  With such a configuration, it is possible to determine in a short time whether or not a person is present on the bedding. Accordingly, the calculation load can be reduced.

It is a block diagram which shows typically the structure of a presence determination apparatus. It is a figure showing typically a body movement value. It is a figure which shows an example of the determination result of the presence or absence of a body movement. It is a figure shown about removal of a body movement period. It is a figure shown about bed presence determination by a gradient. It is a flowchart which shows the process of a presence determination apparatus. It is a figure shown about the presence determination by the change of two load values.

  The presence determination apparatus 100 according to the present invention has a function of determining whether or not a person is present on the bedding. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram schematically showing the configuration of the presence determination apparatus 100 according to the present invention. As shown in FIG. 1, the presence determination device 100 includes a load sensor 11, a storage unit 12, a body motion value calculation unit 13, a body motion determination unit 14, a body motion period removal unit 15, a load change determination unit 16, Each functional unit of the floor determination unit 17 is provided. Each functional unit has a CPU as a core member, and the above-described functional units for performing various processes for determining the presence of the person 1 on the bedding 2 are constructed by hardware and / or software.

  The load sensor 11 is disposed on the bedding 2 and detects a load on the bedding 2. In the present embodiment, the load sensor 11 is disposed on the surface on which the bedding 2 comes in contact with the floor, that is, on the back surface of the bedding 2. In the present embodiment, the bedding 2 will be described using a bed as an example. For this reason, below, the code | symbol 2a is attached | subjected and demonstrated. In the present embodiment, there is one load sensor 11 disposed on the back surface of the bed 2a. Here, the bed 2a includes four legs 4A as shown in FIG. Therefore, the load sensor 11 is disposed only on the back surface of one leg 4A among the four legs 4A. The detection result by the load sensor 11 is transmitted to the storage unit 12 to be described later as an electrical signal indicating a change in load that changes every moment as shown in FIG.

  The storage unit 12 sequentially stores the detection results of the load sensor 11. The detection result is a load on the bed 2 a and is transmitted along the timing detected from the load sensor 11. To store sequentially means to store in the order of transmission. Therefore, the storage unit 12 stores the detection results in the order detected from the load sensor 11. In addition, the storage unit 12 stores time information indicating the time when the detection result is acquired together with the detection result, linked to the detection result. Thereby, it becomes possible to specify when the detection result is detected.

  When the detection result of the load sensor 11 is stored in the storage unit 12, the body motion value calculation unit 13 is based on the change in load for each section T <b> 1 having a cycle shorter than the breathing cycle of the person 1 on the bed 2 a. Then, a body motion value indicating a change in load is calculated (see FIG. 2). The breathing cycle of the person 1 is the time required for the person 1 in the bed 2a to take one breath. Here, when the person 1 is in a stable state of breathing (a state not immediately after exercise or the like), it takes about 3 to 6 seconds per time. Accordingly, the respiration cycle corresponds to about 3 to 6 seconds.

  The period shorter than the respiration period is less than 3 seconds when the respiration period is 3 to 6 seconds, but in the present embodiment, it is assumed to be 1 second for easy understanding. To do. For this reason, the section T1 having a cycle shorter than the breathing cycle corresponds to the section T1 divided every second. In the present embodiment, such a section T1 will be described as a first section T1. The body motion value calculation unit 13 calculates a body motion value for each first section T1 composed of 1 second.

  The body motion value is an index that serves as a standard indicating a change in load. In the present embodiment, the body motion value calculation unit 13 calculates the difference between the maximum value and the minimum value of the load as the body motion value. Here, such a body motion value is calculated for each first interval T1. For this reason, the maximum value of the load is a value when the load becomes maximum in the first section T1, and in FIG. 2, K1 corresponds to each. The minimum value of the load is a value when the load becomes the smallest in the first section T1, and corresponds to K2 in FIG. In the present embodiment, the body motion value calculator 13 calculates the difference between the maximum value K1 and the minimum value K2 as a body motion value. In FIG. 2, such a difference between the maximum value K1 and the minimum value K2 is indicated by a reference sign S.

  Thus, by using the maximum change amount for each first section T1 as the body motion value, it is possible to extract the maximum change amount as a feature related to a change in load. Therefore, the body motion value can be accurately calculated based on such characteristics. The body motion value calculation unit 13 according to the present embodiment calculates such a maximum change amount for each first section T1 to obtain a body motion value. The body movement value calculated by the body movement value calculation unit 13 is transmitted to a body movement determination unit 14 described later.

  The body movement determination unit 14 determines whether there is a body movement of an object on the bed 2a. Specifically, when the body motion value is larger than a preset determination threshold, it is determined that there is a body motion of the person 1. The determination threshold is set to a constant value over the entire first section T1. That is, the determination threshold is set to a constant value regardless of time. Such a determination threshold is stored in the body movement determination unit 14 in advance. The body movement value is calculated for each first section T1 by the body movement value calculation unit 13 and transmitted to the body movement determination unit 14. As shown in FIG. 3, the body motion determination unit 14 compares the body motion value of each first section T <b> 1 with the determination threshold, and when the body motion value is larger than the determination threshold, “body motion present”. If the body motion value is less than or equal to the determination threshold, it is determined that there is no body motion. As shown in FIG. 3, in the present embodiment, it is determined whether or not there is a body movement for each first section T <b> 1 having a cycle shorter than the cycle of breathing.

  In this way, by detecting body movement, it is possible to accurately detect the presence or absence of body movement for each first section T1 even for each first section T1 having a period that is extremely shorter than the breathing period. . For this reason, it is possible to accurately determine when there is body movement. Moreover, since the load sensor 11 is disposed on the back surface of the bed 2a, the person 1 on the bed 2a is not directly touched. Therefore, it can prevent harming the sleep of the person 1 in detecting a body motion. The determination result of the presence or absence of body movement by the body movement determination unit 14 is transmitted to a body movement period removal unit 15 described later.

  The body movement period removing unit 15 excludes detection results detected in a state where there is body movement of an object on the bed 2a. The object on the bed 2a is the person 1 who uses the bed 2a. Whether the person 1 has moved is determined by the body movement determination unit 14 described above. Therefore, the body movement period removing unit 15 is a period in which there is body movement among the detection results stored in the storage unit 12 when the person 1 on the bed 2a has body movement by the body movement determination unit 14. The detection result of is removed.

  Here, the removal of the body motion period by the body motion period removal unit 15 will be described with reference to FIG. FIG. 4A shows a detection result by the load sensor 11 stored in the storage unit 12. In FIG. 4A, the horizontal axis represents time (time), and the vertical axis represents the load detected at the time. In FIG. 4A, a graph is shown for easy understanding, but the storage unit 12 may store the data in a table form, or may store the data in a map form. Of course, it is of course possible to adopt a configuration for storing in other forms.

  FIG. 4A shows a period in which the above-described body movement determination unit 14 determines that there is body movement. It is assumed that this period is between time t1 and time t2. The body movement period removing unit 15 removes the detection result between time t1 and time t2. At that time, as shown in FIG. 4B, the detection result after time t2 is slid so that the detection result at time t2 becomes the same value as the detection result at time t1.

  That is, if the detection result at time t1 is a1 and the detection result at time t2 is a2, the detection result after time t2 is detected while Δa which is the difference between a1 and a2 is reduced. Δt, which is the difference between t1 and t2, is subtracted from the time. As a result, as shown in FIG. 4B, it is possible to appropriately remove the body movement that exists between the time t1 and the time t2 in FIG.

  When the detection result a2 at time t2 is smaller than the detection result a1 at time t1, Δa that is the difference between a1 and a2 is added to the detection result after time t2 and from the detected time. By reducing Δ, which is the difference between t1 and t2, it is possible to appropriately remove the body movement that exists between time t1 and time t2.

  The load change determination unit 16 determines whether or not the load before the predetermined time has decreased based on the detection result at least a predetermined time before and the current detection result stored in the storage unit 12. In the present embodiment, the load change determination unit 16 determines whether or not the current detection result is gradually decreased from the detection result before a predetermined time. Gradually decreasing means that it gradually decreases with a predetermined gradient. Therefore, in the present embodiment, the load change determination unit 16 uses the detection result before the predetermined time, at least one detection result between the predetermined time and the current time, and the detection result at the current time to determine the predetermined value. It is determined whether or not the load before the time has gradually decreased at a predetermined gradient.

  The determination by the load change determination unit 16 will be described with reference to FIG. FIG. 5A shows the detection result of the load sensor 11 from which the period of body movement is removed by the body movement period removing unit 15. The load change determination unit 16 of the present embodiment approximates the detection result with a straight line using a known calculation method. The straight line approximated in this way is shown by a solid line in FIG. In FIG. 5B, the detection result of the load sensor 11 is indicated by a broken line. The load change determination unit 16 calculates the slope of the straight line thus obtained. The load change obtained by the load change determination unit 16, that is, the gradient in this embodiment, is transmitted to the occupancy determination unit 17 described later.

  The bed determination unit 17 determines that the load before the predetermined time is reduced based on the detection result stored at least in the predetermined time and the current detection result stored in the storage unit 12. It is determined that person 1 is present on the top. In the present embodiment, the load change determination unit 16 determines whether or not the current detection result is gradually decreased from the detection result before a predetermined time. Therefore, the presence determination unit 17 determines that the person 1 is present on the bed 2a when the current detection result is gradually decreased from the detection result of the predetermined time.

  Here, it is known that the weight of a person is reduced by about 100 g per hour due to the release of water vapor by sweating or breathing. Therefore, the presence determination unit 17 determines that the person 1 is present on the bed 2a if the gradient transmitted from the load change determination unit 16 is the same as the gradient corresponding to a decrease of about 100 g per hour. To do. On the other hand, when the gradient transmitted from the load change determination unit 16 is extremely smaller than 100 g per hour (for example, when it is reduced by 1 kg or more per hour), or when the gradient increases. It is determined that the person 1 on the bed 2a does not exist.

  For this reason, although the above-mentioned predetermined time is not particularly limited, for example, it is preferable to set it to about 1 hour. This is because a change in load of 100 g can be detected appropriately. Of course, the predetermined time can be set longer than one hour. On the other hand, if the predetermined time is an extremely short time (for example, about several minutes), only a few g of load change occurs. Therefore, it is necessary to prepare a highly sensitive load sensor 11, which causes an increase in cost. Therefore, it is preferable to set the predetermined time in consideration of the cost and the time required for determination.

  Here, in the present embodiment, as described above, the detection result of the period in which the body motion has occurred is removed from the storage unit 12 by the body motion period removing unit 15. Therefore, the presence determination unit 17 determines whether or not the person 1 is present on the bed 2a except for the detection result detected in a state where the person 1 is moving on the bed 2a.

  The occupancy determination unit 17 determines that the person 1 on the bed 2a has left the bed when the current detection result is less than a preset load value. For example, when the weight of the person 1 who regularly uses the bed 2a is known in advance, the load value corresponding to about half the weight of the person 1 may be set as the above-described preset load value. In addition, when the person 1 who regularly uses the bed 2a is unspecified, the load value corresponding to the weight excluding the futon or the pillow placed on the bed 2a may be the above-described preset load value. . When the load value thus set is below, it can be said that the person 1 does not exist on the bed 2a. Therefore, the presence determination unit 17 can determine that the person 1 on the bed 2a has left the floor in such a case.

  Further, the presence determination unit 17 indicates that the person 1 is present on the bed 2a when the detection result stored in the storage unit 12 is constant for a specified time specified by a time shorter than the predetermined time. Cancel the determination that The predetermined time is one hour which is the time set as described above. Therefore, the specified time corresponds to a shorter time. Here, as described above, the person 1 loses weight by a predetermined amount during sleep. Therefore, it can be said that the person 1 does not exist when the weight does not decrease during the specified time and is constant. That is, there is a high possibility that it was not a person 1 but an object. Therefore, the presence determination unit 17 cancels the determination that the person 1 is present on the bed 2a. In this way, the presence determination device 100 determines whether or not the person 1 is present on the bed 2a.

  Next, processing performed by the presence determination apparatus 100 will be described with reference to the flowchart of FIG. In the following description, the description is made according to the procedure of the arithmetic processing, and thus there are portions different from the above description. However, it is naturally possible to cope with the procedure of the flowchart described below by appropriately changing the procedure.

  First, the load detection result detected by the load sensor 11 is stored in the storage unit 12 (step # 01). With respect to the detection results stored in the storage unit 12, the body motion determination unit 14 determines the presence or absence of body motion (step # 02). If there is a body motion (step # 03: Yes), the body motion period removal unit 15 removes the detection result of the period with the body motion from the detection results stored in the storage unit 12 (step # 04). On the other hand, if there is no body movement (step # 03: No), the detection result is not removed by the body movement period removing unit 15.

  When it is determined by the load change determination unit 16 that the detection result stored in the storage unit 12 has a preset load variation (for example, reduced by a predetermined gradient) (step # 05: Yes), The presence determination unit 17 determines that the person 1 is present on the bed 2a (step # 06). On the other hand, when it is determined by the load change determination unit 16 that there is no preset load fluctuation in the detection result stored in the storage unit 12 (step # 05: No), the bed 2a by the occupancy determination unit 17 It is determined that there is no person 1 above (step # 07). The presence determination apparatus 100 performs processing based on such a flow.

[Other Embodiments]
In the embodiment described above, the bedding 2 is described as the bed 2a. However, the scope of application of the present invention is not limited to this. Naturally, the present invention can be applied to the bedding 2 such as a futon regardless of the bed 2a.

  In the above embodiment, an example in which only one load sensor 11 is disposed on the back surface of the bed 2a has been described. However, the scope of application of the present invention is not limited to this. Of course, it is possible to provide a plurality of load sensors 11 on the back surface of the bed 2a.

  Further, the load sensor 11 has been described as being disposed on the back surface of the leg portion 4A of the bed 2a. However, the scope of application of the present invention is not limited to this. For example, it can naturally be provided on the back surface of a mattress or mattress, and of course, if it can detect a load or body movement, it can also be arranged in another part.

  In the above-described embodiment, the presence determination unit 17 has been described as determining that the person 1 is present on the bed 2a when the current detection result is gradually decreased from the detection result before the predetermined time. However, the scope of application of the present invention is not limited to this. The presence determination unit 17 determines that the person 1 is present on the bed 2a when the difference between the detection result a predetermined time ago and the current detection result is within a predetermined determination threshold. It is also possible.

  An example of such a case will be described with reference to FIG. FIG. 7 shows a detection result in which a period in which body movement has occurred is removed by the body movement period removing unit 15. The present time is set as time t4, and a predetermined time before is set as time t3. Further, it is assumed that the load value at time t3 is a3 and the load value at time t4 is a4. In such a case, the load change determination unit 16 calculates a difference as a change in load between time t3 and time t4. Let this difference be Δb.

  The occupancy determination unit 17 determines whether this Δb is within a predetermined determination threshold. When Δb is within a preset determination threshold, it is determined that the person 1 is present on the bed 2a. On the other hand, when Δb is not within the preset determination threshold, it is determined that the person 1 does not exist on the bed 2a. Even if Δb is within a predetermined determination threshold value, as described in the above embodiment, the detection result is between a time t3 and a time t4 for a specified time defined by a time shorter than the time. Is constant, that is, when Δb is zero, it is preferable to determine that the person 1 does not exist on the bed 2a. Even with such a configuration, it is possible to appropriately determine whether or not the person 1 is present on the bed 2a.

  In the above embodiment, the occupancy determination unit 17 has been described as determining by excluding the detection result detected in the state where the person 1 on the bed 2a has moved. However, the scope of application of the present invention is not limited to this. Of course, the presence determination unit 17 can also determine the detection result without removing the detection result detected in the state of body movement. Alternatively, it is of course possible to calculate the moving average without removing the detection result detected in the state of body movement, and make a determination based on this. Moreover, although the said embodiment demonstrated the method of removing the detection result detected in the state with a body motion, this is only an example and it can naturally remove using another method.

  In the above embodiment, the occupancy determination unit 17 has been described as determining that the person 1 on the bed 2a has left the bed when the current detection result is less than a preset load value. However, the scope of application of the present invention is not limited to this. Of course, it is possible to adopt a configuration in which it is not determined that the person 1 on the bed 2a has left the bed even if the current detection result is less than a preset load value. For example, the presence determination unit 17 determines that the person 1 has left the bed 2a when the current detection result fluctuates more than a preset load value with respect to the detection result a predetermined time ago. It is also possible to do.

  In the above-described embodiment, the occupancy determination unit 17 has the person 1 on the bed 2a when the detection result stored in the storage unit 12 is constant for a specified time specified by a time shorter than a predetermined time. Is described as being configured to cancel the determination that exists. However, the scope of application of the present invention is not limited to this. Of course, the presence determination unit 17 can be configured not to cancel the determination that the person 1 is present on the bed 2a even if the detection result is constant.

  In the above embodiment, the occupancy determination unit 17 determines the person 1 on the bed 2a when it is determined that the load before the predetermined time has decreased based on the detection result at least a predetermined time ago and the current detection result. As described above, it is determined that exists. For example, the occupancy determination unit 17 sets the person on the bed 2a based on whether or not the amount of variation between the current detection result and the detection result at a past time before a predetermined time is less than a predetermined determination threshold. It is preferable to make a preliminary determination as to whether or not 1 exists.

  The current detection result is the current detection result. The detection result at a time point before the predetermined time is, for example, the detection result of yesterday, and is preferably a detection result at the same time as the present time. The preset determination threshold is preferably set to ± 10% of the detection result of a past time point before the predetermined time, that is, the detection result of yesterday. Moreover, it is preferable to use ± 10% of the detection result yesterday at the same time as the present time. Of course, it is naturally possible to set a value larger or smaller than ± 10%. Thus, if the difference between the current detection result and the detection result at the same time yesterday is within ± 10% of the detection result at the same time yesterday, the presence determination unit 17 has the person 1 in the bed 2a. It is preferable to determine that it is. By performing such preliminary determination, it is possible to accurately determine whether or not the person 1 is present on the bed 2a.

  INDUSTRIAL APPLICABILITY The present invention can be used for an in-bed determination device that determines whether a person is present on bedding.

1: Person 2: Bedding 2a: Bed 11: Load sensor 12: Storage unit 17: In-bed determination unit 100: In-bed determination device

Claims (7)

A load sensor disposed on the bedding and detecting a load on the bedding;
A storage unit for sequentially storing detection results of the load sensors;
There is a person on the bedding when it is determined that the load before the predetermined time is reduced based on the detection result at least a predetermined time before stored in the storage unit and the current detection result. A presence determination unit that determines that the
A presence determination device comprising:   The presence determination unit according to claim 1, wherein the presence determination unit determines that a person is present on the bedding when the current detection result is gradually decreased from the detection result before the predetermined time. apparatus.   The presence determination unit determines that a person is present on the bedding when a difference between the detection result before the predetermined time and the detection result at the present time is within a predetermined determination threshold. The presence determination apparatus according to 1.   The occupancy determination device according to any one of claims 1 to 3, wherein the occupancy determination unit performs determination by removing a detection result detected in a state in which an object on the bedding is moving.   The occupancy determination unit according to any one of claims 1 to 4, wherein the occupancy determination unit determines that a person on the bedding has left the bed when the current detection result is less than a preset load value. Judgment device.   The presence determination unit has a person on the bedding when the detection result stored in the storage unit is constant for a predetermined time defined by a time shorter than the predetermined time. The presence determination apparatus according to any one of claims 1 to 5, wherein the determination is canceled.   The presence determination unit determines whether the person on the bedding is based on whether the amount of change between the detection result at the present time and the detection result at a time earlier than the predetermined time is less than a predetermined determination threshold. The occupancy determination device according to any one of claims 1 to 6, wherein a preliminary determination is made as to whether or not an object exists.

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