Presence detection system, presence determination device, and presence determination method

Abstract

To enable presence determination corresponding to layout changes or the like.SOLUTION: A presence detection system according to one aspect includes a transmitting unit that is disposed on one side of a space to be detected and transmits radio wave signals; a receiving unit that is disposed on the other side of the space with respect to the one side and receives the radio wave signals; a presence determination unit that compares a first parameter indicating the reception state of the received radio wave signals with a threshold value to determine the presence of an object in the space; and a setting unit that sets the threshold value based on the first parameter in the radio wave signals received in a first state of the space and the first parameter in the radio wave signals received in a second state of the space.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a presence detection system, a presence determination device, and a presence determination method. [Background technology]

[0002] Conventionally, presence detection systems have been proposed that detect whether or not a person is present in a space by utilizing the phenomenon in which the received signal strength of radio waves fluctuates due to the movement of people in a multipath environment in a space such as an indoor space. For example, Patent Document 1 proposes a technology that reduces the power consumption of equipment used for presence detection by determining the activity state of people present in a space and increasing or decreasing the frequency of communication of detection signals based on the results of the determination. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6342077 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 uses a fixed threshold value for presence determination. However, it is desirable to set the threshold value for presence determination according to the size of the space and the structure within the space, and the technology described in Patent Document 1 has difficulty responding to changes in the layout of the room, for example. In view of the above circumstances, an object of the present invention is to enable presence determination that corresponds to layout changes and the like. [Means for solving the problem]

[0005] In order to solve the above problem, a presence detection system according to one embodiment of the present invention comprises a transmitter that is deployed on one side of a space to be detected and transmits a radio wave signal; a receiver that is deployed on the other side of the space and receives the radio wave signal; a presence determination unit that compares a first parameter indicating the reception state of the received radio wave signal with a threshold value to determine the presence of an object in the space; and a setting unit that sets the threshold value based on the first parameter in the radio wave signal received in a first state of the space and the first parameter in the radio wave signal received in a second state of the space.

[0006] A presence detection system according to one aspect of the present invention further includes an update unit that updates the threshold value based on the first parameter in the radio wave signal received in the third state of the space. A presence detection system according to one aspect of the present invention further includes a water submersion determination unit that determines whether the space is submerged in water based on a second parameter that indicates the reception state of the received radio wave signal.

[0007] In the presence detection system according to one aspect of the present invention, the first parameter indicates fluctuation of the radio wave signal, and the second parameter indicates reception strength of the radio wave signal. A presence determination device according to one embodiment of the present invention comprises a presence determination unit that performs a presence determination in the space by comparing a first parameter indicating the reception state of a radio wave signal transmitted from one side of a space to be detected and received at the other side with a threshold, and a setting unit that sets the threshold based on the first parameter in the radio wave signal received in a first state of the space and the first parameter in the radio wave signal received in a second state of the space.

[0008] A presence determination method according to one embodiment of the present invention includes the steps of: determining the presence of an object in a space to be detected by comparing a first parameter indicating the reception state of a radio wave signal transmitted from one side of the space and received at the other side with a threshold; and setting the threshold based on the first parameter in the radio wave signal received in the first state of the space and the first parameter in the radio wave signal received in the second state of the space; and is executed on an information processing device. [Effects of the Invention]

[0009] According to the present invention, it is possible to determine the presence of a component in response to layout changes and the like. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating a schematic diagram of an occupancy detection system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing the functional structure of a server. [Figure 3] 10 is a flowchart showing a processing operation of a server. [Figure 4] FIG. 10 is a diagram illustrating an example of the fluctuation width of the reception strength in an absent state. [Figure 5] FIG. 10 is a diagram illustrating an example of the fluctuation width of the reception strength in a room where a person is present. [Figure 6] FIG. 10 is a diagram illustrating an example of threshold values ​​in the initial setting. [Figure 7] FIG. 10 is a diagram illustrating an example of a fluctuation width calculated when updating a threshold value. [Figure 8] FIG. 10 is a diagram illustrating an example of an updated threshold value. [Figure 9] FIG. 10 is a diagram showing an example of flooding above the floor level. [Figure 10] 10 is a graph showing an example of a signal when submerged in water. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the present invention, and not all of the combinations of features described in the embodiments are necessarily essential to the configuration of the present invention. The configuration of the embodiments may be modified or changed as appropriate depending on the specifications of the device to which the present invention is applied and various conditions (such as usage conditions and usage environment).

[0012] The technical scope of the present invention is defined by the claims and is not limited by the individual embodiments described below. The drawings used in the following description may differ in scale and shape from the actual structure to make each configuration easier to understand. The correspondence between the drawings may also differ in some places to simplify the description. Components shown in previously described drawings may be referenced as appropriate in the description of subsequent drawings.

[0013] <Room presence detection system> FIG. 1 is a diagram schematically illustrating an occupancy detection system according to one embodiment of the present invention. The presence detection system 100 corresponds to one embodiment of the presence detection system of the present invention, and detects the presence of a person 210 in the interior space of a room 200. That is, the presence detection system 100 detects the presence of the person 210. Presence detection is an example of presence detection, in which presence determination is performed. The person 210 corresponds to one example of an object that is the target of presence determination. Furthermore, the presence detection system 100 of this embodiment is, as one example, a system that detects the presence of the person 210 and detects water intrusion into the room 200.

[0014] The presence detection system 100 includes a transmitting device 110, a receiving device 120, and a cloud server . The transmitting device 110 is, for example, arranged on one side of the interior space of the room 200, and is, for example, battery-powered. The transmitting device 110 corresponds to an example of the transmitting unit referred to in the present invention, and transmits, for example, a beacon signal of radio waves in the 2.4 GHz band via Bluetooth (registered trademark) as a detection signal 150 for detecting the person 210. The detection signal 150 includes, for example, an address corresponding to individual information of the transmitting device 110, and remaining battery charge information.

[0015] The detection signal 150 is preferably a radio wave signal in the 2.4 GHz band that can be used in combination with the detection of the presence of a person 210 and the water intrusion detection described below, but if the purpose is to detect the presence of an object other than the person 210, a radio wave signal in a band other than the 2.4 GHz band may also be used. The receiving device 120 corresponds to an example of a receiving unit referred to in the present invention, and is arranged, for example, on the other side of the interior space of the room 200. The receiving device 120 is powered by, for example, a 100V AC commercial power source and receives the detection signal 150. The receiving device 120 transmits information indicating the signal strength of the received detection signal 150, for example, over a network such as the Web, for example, by LTE (Long Term Evolution) communication, and delivers the information to the server 130. The receiving device 120 may transmit the information by Wi-Fi (Wireless Fidelity) communication or by wired communication.

[0016] It should be noted that the space between the transmitting device 110 and the receiving device 120 is the space to be detected, and the installation locations of the transmitting device 110 and the receiving device 120 are not limited to the edges of the room 200. For example, a configuration is also possible in which the receiving device 120 is installed in the center of the room 200, and multiple transmitting devices 110 are installed in various locations in the room 200. In this configuration, the receiving device 120 receives the detection signal 150 from each transmitting device 110.

[0017] The server 130 is, for example, a virtual server such as a cloud server, and determines whether the person 210 is present in the room based on the information received from the receiving device 120, and also determines whether the room 200 has been flooded. The server 130 may be a web server other than a cloud server, or may be a physical server in an on-premise environment. The server 130 uses the fluctuation width of the reception strength of the detection signal 150 to determine whether the person 210 is present in the room, and uses both the absolute value and the fluctuation width of the reception strength of the detection signal 150 to determine whether the room has been flooded.

[0018] FIG. 2 is a block diagram showing the functional structure of the server 130. The server 130 includes a signal analysis unit 131 , an occupancy determination unit 132 , a flood determination unit 133 , an initial setting unit 134 , and a threshold update unit 135 . The signal analysis unit 131 analyzes the information on the reception strength received from the receiving device 120 to obtain the fluctuation width and absolute value of the reception strength of the detection signal 150. The fluctuation width of the detection signal 150 corresponds to an example of the first parameter referred to in the present invention, and the absolute value of the reception strength corresponds to an example of the second parameter referred to in the present invention.

[0019] The presence determining unit 132 corresponds to an example of the presence determining unit referred to in the present invention, and determines whether the person 210 is present in the room based on the fluctuation width of the detection signal 150 . The flood determining unit 133 corresponds to an example of the flood determining unit referred to in the present invention, and performs flood determination based on the fluctuation width of the detection signal 150 and the reception strength of the detection signal 150 .

[0020] The initial setting unit 134 corresponds to an example of the setting unit referred to in the present invention, and sets the threshold value used by the occupancy determination unit 132 for occupancy determination as the initial setting in the occupancy detection system 100 . The threshold updating unit 135 corresponds to an example of the updating unit referred to in the present invention, and updates the threshold for determining whether a person is present in the room periodically or in response to an instruction operation.

[0021] FIG. 3 is a flowchart showing the processing operation of the server 130. After powering on, server 130 executes the processes of steps S101 to S103 as initial settings, and then repeatedly executes the processes of steps S104 to S113. Server 130 also executes the processes of steps S105 to S109 as normal processing, and executes the processes of steps S110 to S113 as emergency processing.

[0022] In step S101, when person 210 is absent from room 200, receiving device 120 transmits reception strength information to server 130 in accordance with an instruction operation by an installer of presence detection system 100 or the like. Then, signal analysis unit 131 analyzes the reception strength information and calculates the fluctuation width of reception strength in the absence state.

[0023] FIG. 4 is a diagram showing an example of the fluctuation width of the reception strength in an unattended state. The horizontal axis in FIG. 4 indicates time, and the vertical axis indicates reception intensity. Even when person 210 is absent from room 200, the reception strength fluctuates as shown in graph 310 due to variations in the transmission power of the transmitting device, variations in the measurement of the reception strength of the receiving device, etc. When person 210 is absent, a value of "a", for example, is obtained as the fluctuation width.

[0024] 3, in a state where person 210 is present in the room, receiving device 120 sends information about the reception strength to server 130 in accordance with an instruction operation. Then, signal analysis unit 131 analyzes the information about the reception strength and calculates the fluctuation width of the reception strength in the presence state.

[0025] FIG. 5 is a diagram showing an example of the fluctuation width of the reception strength in the presence state. The horizontal axis in FIG. 5 also indicates time, and the vertical axis indicates reception intensity. When person 210 is present in room 200, the reception strength fluctuates more than when no one is present, as shown in graph 320, due to the movement of person 210. When person 210 is present in the room, for example, a value "b" is obtained as the fluctuation width, and value "b" is greater than value "a".

[0026] In step S103 of FIG. 3, the initial setting unit 134 calculates a threshold value for determining whether or not a person is present in the room based on the fluctuation width of the occupancy state and the fluctuation width of the vacant state, and sets the calculated threshold value as the threshold value of the occupancy determining unit 132. FIG. 6 is a diagram showing an example of threshold values ​​in the initial setting.

[0027] The horizontal axis in FIG. 6 indicates whether or not a person 210 is present, and the vertical axis indicates the fluctuation width in terms of relative signal strength. As the initial setting threshold 410, for example, the intermediate value "(a+b) / 2" between the value "b" of the fluctuation width when a person is present and the value "a" of the fluctuation width when no one is present is calculated and set. In this way, the threshold value 410 is calculated and set from the fluctuation width of each of the occupancy state and the vacancy state, so that an appropriate threshold value 410 can be calculated even without information such as the size or layout of the room 200, making it possible to appropriately determine whether the person is present in the room.

[0028] In step S104 of Fig. 3, it is determined whether or not an emergency is occurring. An emergency is, for example, when an earthquake, tsunami, heavy rain, or the like occurs, and in an emergency, the server 130 receives an emergency designation from the administrator of the occupancy detection system 100, etc. If the server 130 has not received an emergency designation, it is normal. The determination of whether or not an emergency is occurring may be made, for example, by a dedicated determination unit not shown, or by the occupancy determination unit 132 or flood determination unit 133.

[0029] If it is determined in step S104 that the current time is normal (step S104; No), the signal analysis unit 131 calculates the fluctuation width of the received signal strength at the current time in step S105. Then, in step S106, the threshold update unit 135 determines whether it is time to update the threshold. The updating of the threshold will be described later.

[0030] If it is determined in step S106 that it is not time to update the threshold (step S106; No), in step S108, the presence determination unit 132 compares the fluctuation width of the reception strength at the current time with the threshold to determine whether the person 210 is present in the room 200. For example, if the fluctuation width of the reception strength at the current time is larger than the threshold, it is determined that the person 210 is present in the room 200, and if it is smaller than the threshold, it is determined that the person 210 is not present in the room 200.

[0031] In step S109, the presence determination unit 132 notifies the system administrator or the like of the determination result. The notification of the determination result may be, for example, displayed on a display or sent by email. The system administrator or the like who receives the notification of the determination result can confirm the presence of, for example, an intruder, and can take action such as reporting to the police or a security company. After the notification of the result, the process returns to step S104.

[0032] Here, the updating of the threshold value will be described. As described above, the threshold used for determining whether or not a person 210 is present in the room is updated periodically or in response to an instruction from a system administrator or the like. Therefore, in step S106, the threshold update unit 135 determines whether or not either the periodic update timing has arrived or an instruction to update has been received. The update timing may be, for example, in the early hours of the morning one month after the previous update. The instruction to update is executed by a system administrator or the like when no person 210 is present in the room 200.

[0033] When the update timing is reached or an instruction operation for update is received (step S106; Yes), the threshold update unit 135 updates the threshold used for determining whether or not a room is present in the room in step S107. The threshold is updated based on the fluctuation width calculated in step S105, and the calculated fluctuation width corresponds to the fluctuation width in an vacant state.

[0034] Fig. 7 is a diagram showing an example of the fluctuation width calculated when the threshold is updated, and Fig. 8 is a diagram showing an example of the updated threshold. The horizontal axis of Fig. 7 indicates time, and the vertical axis indicates reception strength. The horizontal axis of Fig. 8 indicates the presence or absence of person 210, and the vertical axis indicates the fluctuation width as relative signal strength. The threshold is updated when the person 210 is absent from the room 200, but when the threshold is updated, the layout of the room 200 may have changed since the initial setting or the previous update. In this case, the value of the fluctuation width in the absence state, "a", shown in Fig. 4, changes by, for example, Δa to become "a+Δa", as shown in Fig. 7.

[0035] In response to such changes in the fluctuation amplitude of the vacant state, as shown in FIG. 8, the new threshold 420 is set to a value that is changed by, for example, a value "Δa" from the threshold 410 before the update. That is, if the threshold 410 before the update is a value "(a+b) / 2", the new threshold 420 becomes a value "(a+b) / 2+Δa". By updating the threshold in this manner, it becomes possible to determine whether or not a person is present in the room in response to changes in the layout of the room 200, for example. Note that the new threshold 420 may be set to a value of "(a+Δa+b) / 2", for example.

[0036] Next, the processing operation in an emergency will be described. 3, if an emergency is determined (step S104; Yes), the signal analysis unit 131 calculates the fluctuation width and absolute value of the current reception strength in step S110. Then, in step S111, the flood determination unit 133 determines the possibility that at least one of a person 210 is present in the room and that water is present above the floor, based on the fluctuation width of the reception strength. Furthermore, in step S112, the flood determination unit 133 performs a flood determination based on the reception strength.

[0037] 9 and 10 are diagrams illustrating the principle of flood detection. Fig. 9 shows an example of flooding above the floor, and Fig. 10 shows a graph of the signal during flooding. The horizontal axis of Figure 10 indicates time, the left vertical axis indicates signal strength, and the right vertical axis indicates water depth. In the graph of Figure 10, small black circles indicate signal strength, and large white circles indicate water depth.

[0038] 9, when water 500 enters room 200 and causes flooding above the floor, detection signal 150 transmitted from transmitting device 110 travels through multiple paths, including a path that reaches receiving device 120 directly and a path that reaches receiving device 120 after being reflected by the surface of water 500. Then, due to fluctuations on the surface of water 500, the signal strength fluctuates as shown from time t1 to t2 and from time t5 to t6 in the graph of FIG.

[0039] As described above, the signal strength fluctuates significantly even when a person 210 is present in the room 200. Therefore, if the signal strength fluctuates significantly during an emergency, it is determined that at least one of the following has occurred: the room 200 is flooded above the floor level, or there is a person in need of rescue present in the room. On the other hand, if the water 500 in the room 200 increases, for example, at time t2 in the graph of Fig. 10, the water depth becomes 0, and as shown in the diagram below the graph, the water 500 reaches the installation position of the transmitting device 110. Then, as the water depth increases further, the signal strength decreases rapidly, as shown from time t2 to t3 in the graph.

[0040] Between times t3 and t4 on the graph, the water depth reaches 5 cm, which corresponds to the size of the transmitting device 110, and as shown in the diagram at the bottom of the graph, the transmitting device 110 is submerged in the water 500. For this reason, between times t3 and t4 on the graph, the signal strength becomes clearly low, and it is confirmed that the water has reached a level where the transmitting device 110 is submerged. After that, between times t4 and t5 on the graph, the water 500 in the room 200 recedes, and the transmitting device 110 appears above the water 500, and the signal strength also increases rapidly.

[0041] Based on this principle, in an emergency, flooding and the like are determined in steps S111 and S112 of FIG. 3. The determination results in steps S111 and S112 are notified to a system administrator or the like in step S113. The system administrator or the like who receives the notification of the determination result can know whether the transmitting device 110 is submerged in water, whether the water is above the floor level, or whether there is a person in need of rescue in the room. The system administrator or the like can then take action such as reporting the occurrence of flooding or the possibility of a person in need of rescue. After the notification of the result, the process returns to step S104 above.

[0042] As described above, the presence detection system 100 of this embodiment is effectively used in both normal times and emergencies. In the above explanation, an example is shown in which the presence determination unit and setting unit referred to in the present invention are provided in the server 130 that communicates with the receiving device 120, but the presence determination unit and setting unit referred to in the present invention may also be incorporated into the receiving device 120, for example, as an edge computer.

[0043] In addition, in the above explanation, an example of a presence detection system of the present invention is shown as a presence detection system 100 that detects the presence of a person in an indoor space, but the presence detection system of the present invention may also be a system that detects the presence of a person in an outdoor space, or a system that detects the presence of something other than a person.

[0044] In addition, in the above explanation, an example of the presence detection system of the present invention is shown as occupancy detection system 100, which detects presence in a room under normal circumstances and detects water intrusion in an emergency, but the presence detection system of the present invention may also be a system that only detects presence in a room and does not detect water intrusion. [Explanation of symbols]

[0045] 100 Presence Detection System 110 Transmitting device 120 receiving device 130 servers 131 Signal analysis section 132 Room presence determination department 133 Flood detection section 134 Initial setting section 135 Threshold Update Unit 150 Detection signal 200 rooms 210 People 500 water

Claims

1. a transmitter disposed on one side of the space to be detected and configured to transmit radio signals; a receiving unit disposed on the other side of the space relative to the one side and receiving the radio wave signal; a presence determination unit that compares a first parameter indicating a reception state of the received radio wave signal with a threshold value to determine the presence of an object in the space; a setting unit that sets the threshold value based on the first parameter of the radio wave signal received in a first state of the space and the first parameter of the radio wave signal received in a second state of the space; A presence detection system comprising:

2. The presence detection system according to claim 1 , further comprising an update unit that updates the threshold value based on the first parameter in the radio wave signal received in a third state of the space.

3. The presence detection system according to claim 1 , further comprising a water inundation determination unit that determines whether the space is flooded with water based on a second parameter that indicates a reception state of the received radio wave signal.

4. 4. The presence detection system according to claim 3, wherein the first parameter indicates a fluctuation width of the radio wave signal, and the second parameter indicates a reception strength of the radio wave signal.

5. a presence determination unit that compares a first parameter indicating a reception state of a radio wave signal transmitted from one side of a space to be detected and received at the other side with a threshold value to determine presence in the space; a setting unit that sets the threshold value based on the first parameter of the radio wave signal received in a first state of the space and the first parameter of the radio wave signal received in a second state of the space; A presence determination device comprising:

6. a step of comparing a first parameter indicating a reception state of a radio wave signal transmitted from one side of a space to be detected and received at the other side with a threshold value to determine the presence of an object in the space; setting the threshold value based on the first parameter of the radio wave signal received in a first state of the space and the first parameter of the radio wave signal received in a second state of the space; The presence determination method is executed on an information processing device.

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