Motion detection system, wiring device, load system, motion detection method, and program

Abstract

To improve the sensitivity of detecting moving objects. [Solution] The motion detection system 1 comprises a radio wave sensor 10 and a detection unit 22. The radio wave sensor 10 transmits a frequency-modulated radio wave, which is a transmission wave, to the detection target space during each of a plurality of detection periods. When the radio wave sensor 10 receives a reflected wave that has been reflected by an object present in the detection target space, it outputs an output signal based on the transmission wave and the reflected wave. The detection unit 22 performs a difference calculation process multiple times to determine the time difference of the output signals during the difference calculation period between two detection periods by calculating the difference between two output signals output by the radio wave sensor 10 during two different detection periods. The detection unit 22 obtains an integrated value by accumulating the calculation results of the time differences in a plurality of different difference calculation periods, and detects the presence or absence of a moving object based on the comparison result obtained by comparing the integrated value with a threshold value.

Description

Technical Field

[0001] The present disclosure relates to a moving object detection system, a wiring device, a load system, a moving object detection method, and a program. More specifically, the present disclosure relates to a moving object detection system, a wiring device, a load system, a moving object detection method, and a program that detect a moving object using a radio wave sensor.

Background Art

[0002] Patent Document 1 discloses an intrusion detection device including a transmission means, a reception means, a received wave intensity measurement means, and a human body determination means. The transmission means transmits radio waves into a detection area. The reception means receives the reflected wave of the transmitted radio wave. The received wave intensity measurement means measures the received wave intensity of the reflected wave received by the reception means. The human body determination means determines whether or not a human body has entered the detection area based on the measured received wave intensity.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a person stands still or sits on a chair in the detection area, the movement of the human body is small, so there is a possibility that the human body determination means cannot detect the human body in the detection area.

[0005] An object of the present disclosure is to provide a moving object detection system, a wiring device, a load system, a moving object detection method, and a program capable of improving the sensitivity to detect a moving object.

Means for Solving the Problems

[0006] A motion detection system according to one aspect of the present disclosure comprises a radio wave sensor and a detection unit. The radio wave sensor transmits a frequency-modulated radio wave, which is a transmission wave, to the detection target space during each of a plurality of detection periods, and when it receives a reflected wave that has been reflected by an object in the detection target space, it outputs an output signal based on the transmission wave and the reflected wave. The detection unit performs a difference calculation process multiple times to determine the time difference of the output signals during a difference calculation period between two of the detection periods by calculating the difference between two of the output signals that the radio wave sensor outputs during two different detection periods. The detection unit obtains an integrated value by accumulating the calculation results of the time differences during a plurality of different difference calculation periods, and detects the presence or absence of a moving object based on a comparison result obtained by comparing the integrated value with a threshold value.

[0007] A wiring device according to one aspect of the present disclosure comprises a motion detection system, a load connection section, and a load control section. A load is connected to the load connection section. The load control section controls the operating state of the load connected to the load connection section based on the detection result of the motion detection system.

[0008] A load system according to one aspect of the present disclosure comprises the motion detection system, a load, and a load control unit. The load control unit controls the operating state of the load based on the detection result of the motion detection system.

[0009] A motion detection method according to one aspect of the present disclosure includes an acquisition process and a detection process. In the acquisition process, an output signal output from a radio wave sensor for each detection period is acquired. In each of the multiple detection periods, the radio wave sensor transmits a frequency-modulated radio wave, which is a transmission wave, to the detection target space, and when it receives a reflected wave that has been reflected by an object in the detection target space, it outputs an output signal based on the transmission wave and the reflected wave. In the detection process, a difference calculation process is performed multiple times to determine the time difference of the output signals in a difference calculation period between two of the detection periods by calculating the difference between two of the output signals output by the radio wave sensor in each of the two different detection periods. In the detection process, an integrated value is obtained by accumulating the calculation results of the time differences in a plurality of different difference calculation periods, and the presence or absence of a moving object is detected based on a comparison result obtained by comparing the integrated value with a threshold value.

[0010] A program according to one aspect of this disclosure is a program for causing one or more processors to execute the motion detection method. [Effects of the Invention]

[0011] According to this disclosure, it is possible to improve the sensitivity of detecting moving objects. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic block diagram of a wiring device and load system equipped with a motion detection system according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a conceptual diagram of a room to which the wiring device equipped with the motion detection system described above is applied. [Figure 3] Figure 3 is a graph showing the changes in the frequencies of the transmitted and received waves transmitted by the radio wave sensor in the motion detection system described above. [Figure 4] Figure 4 is a diagram that conceptually explains the inter-frame difference performed by the motion detection system described above. [Figure 5]Figure 5 is a frequency spectrum diagram showing an example of the FFT result obtained by the motion detection system described above in frame Fr0. [Figure 6] Figure 6 is a frequency spectrum diagram showing an example of the FFT results obtained by the motion detection system described above in frame Fr1. [Figure 7] Figure 7 is a frequency spectrum diagram showing an example of the time difference obtained by the motion detection system described above from the FFT results of frame Fr0 and frame Fr1. [Figure 8] Figure 8 is a frequency spectrum diagram showing an example of a single time difference obtained by the motion detection system described above. [Figure 9] Figure 9 is a frequency spectrum diagram showing an example of the integration result obtained by integrating multiple time differences obtained by the motion detection system described above. [Figure 10] Figure 10 is a conceptual diagram illustrating the process by which the motion detection system described above accumulates multiple time differences. [Figure 11] Figure 11 is a distribution map showing the distribution of points representing moving objects detected by the motion detection system described above. [Figure 12] Figure 12 is a flowchart illustrating the operation of the wiring device mentioned above. [Modes for carrying out the invention]

[0013] Hereinafter, the motion detection system, wiring device, load system, and motion detection method according to the embodiments will be described in detail with reference to the drawings. However, the figures described in the following embodiments are schematic diagrams, and the dimensional ratios of the size of each component do not necessarily reflect the actual dimensional ratios. Furthermore, the configurations described in the following embodiments are merely examples of the present disclosure. The present disclosure is not limited to the following embodiments, and various modifications are possible depending on the design, etc., as long as the effects of the present disclosure can be achieved.

[0014] (Embodiment) (1) Overview As shown in FIG. 1, the moving object detection system 1 according to this embodiment includes a radio wave sensor 10 and a detection unit 22.

[0015] In each of a plurality of detection periods, the radio wave sensor 10 transmits a transmission wave, which is a frequency-modulated radio wave, to a detection target space SP1 (see FIG. 2). When the radio wave sensor 10 receives a reflected wave obtained by reflection of the transmission wave by an object existing in the detection target space SP1, the radio wave sensor 10 outputs an output signal based on the transmission wave and the reflected wave.

[0016] The detection unit 22 performs a difference calculation process a plurality of times to obtain a time difference of the output signal in a difference calculation period between two detection periods by calculating a difference between two output signals respectively output by the radio wave sensor 10 in two different detection periods.

[0017] The detection unit 22 obtains an integrated value obtained by integrating calculation results of the time differences in a plurality of different difference calculation periods, and detects the presence or absence of a moving object based on a comparison result of comparing the integrated value with a threshold value.

[0018] As described above, the detection unit 22 performs a difference calculation process multiple times to determine the time difference of the output signals during the difference calculation period between two detection periods by calculating the difference between two output signals output by the radio wave sensor 10 during two different detection periods. Figure 10 is a conceptual diagram illustrating the process by which the detection unit 22 calculates the time difference multiple times. The detection unit 22 calculates the time difference DS during the difference calculation period PA to PD between two detection periods by calculating the difference between the output signals during two of the multiple detection periods (for example, frames FrA to FrE). Here, the difference calculation periods PA to PD, for which the time difference is calculated in each of the multiple difference calculation processes, are different periods. The detection unit 22 then calculates the integrated value Sa by integrating the calculation results of the time difference DS during the multiple different difference calculation periods PA to PD. In Figure 10, the detection unit 22 calculates the integrated value Sa by integrating the results of the time difference DS calculated over four difference calculation periods PA to PD. However, it may also integrate the results of the time difference DS calculated over two or three difference calculation periods, or it may integrate the results of the time difference DS calculated over five or more difference calculation periods. Furthermore, when the detection unit 22 calculates the time difference multiple times, the time lengths of the difference calculation periods PA to PD between the two output signals for which the time difference is calculated may be the same, or they may be different.

[0019] The motion detection system 1 of this embodiment detects moving objects (hereinafter sometimes referred to as "motions"), and in this embodiment, the object to be detected by the motion detection system 1 is, for example, a person. The detection target space SP1 in which the motion detection system 1 detects the presence or absence of an object is a space in which a person may be present, for example, the interior space of a residential or non-residential building used by a person. When the motion detection system 1 detects an object moving in the detection target space SP1, it determines that this object is a person. The motion detection system 1 may also determine that an object present in the detection target space SP1 is a person based on the size or height (height) of the object detected in the detection target space SP1.

[0020] The magnitude of the output signal output by the radio wave sensor 10 is proportional to the distance from the radio wave sensor 10 to the object. Therefore, the time difference between the two output signals output by the radio wave sensor 10 during the two detection periods is proportional to the amount of motion the object moved during the two detection periods.

[0021] In this case, if a person, which is an object in the detection target space SP1, is standing still or sitting in a chair, the movement of the person in the detection target space SP1 will be minute movements that occur when breathing or shifting, and the calculated time difference will also be a small value. In the motion detection system 1 of this embodiment, the detection unit 22 calculates an integrated value by accumulating the results of multiple time difference calculations, so even if the movement of the person in the detection target space SP1 is minute and the individual time difference calculation results are small, the value of the integrated time difference can be made large. Furthermore, since the detection unit 22 detects the presence or absence of a moving object based on the comparison result obtained by comparing the level of the integrated value with the threshold, it becomes easier to detect the presence of a moving object even if the movement of an object (e.g., a person) in the detection target space SP1 is minute. Therefore, the motion detection system 1 of this embodiment can improve the sensitivity of detecting moving objects.

[0022] (2) Details The motion detection system 1 of this embodiment is used to detect moving objects using a radio wave sensor 10.

[0023] The motion detection system 1 is provided in a wiring device 100 installed on the ceiling 401 of a room 400 in which a person 300 may be present (see Figure 2). In other words, in this embodiment, the interior space of the room 400 becomes the detection target space SP1 in which the motion detection system 1 detects the presence or absence of a person. The motion detection system 1 includes a housing 2 that houses a radio wave sensor 10, and the housing 2 is placed on a wall 402 next to the detection target space SP1, or on the ceiling 401 above the detection target space SP1. In the following embodiment, the case in which the housing 2 is placed on the ceiling 401 above the detection target space SP1 will be described as an example. In this case, the radio wave sensor 10 is placed on the lower surface of the housing 2 in a state in which it can transmit radio waves to a detection area A1 set in the detection target space SP1 below the ceiling 401.

[0024] Furthermore, in this embodiment, since the motion detection system 1 is provided in the wiring device 100, the housing of the wiring device 100 becomes the housing 2 of the motion detection system 1. The housing 2 of the motion detection system 1 further houses the detection unit 22. If the radio wave sensor 10 and the detection unit 22 were housed in separate housings, the installation work for the radio wave sensor 10 and the detection unit 22 would need to be performed separately. In this embodiment, since the radio wave sensor 10 and the detection unit 22 are housed in a single housing 2, the installation work for the radio wave sensor 10 and the detection unit 22 can be performed at once, simplifying the installation process.

[0025] Furthermore, the wiring device 100 of this embodiment includes a motion detection system 1, a load connection section 50, and a load control unit 23. A load 3 is connected to the load connection section 50. The load control unit 23 controls the operating state of the load 3 connected to the load connection section 50 based on the object detection result by the motion detection system 1. The load 3 whose operating state is controlled by the load control unit 23 is, for example, a lighting load, but it may also be an air conditioning load such as a ventilation fan, or a load other than a lighting load or air conditioning load.

[0026] (2.1) Configuration The configurations of the motion detection system 1 and the wiring device 100 will be described in more detail below with reference to Figures 1 to 11.

[0027] (2.1.1) Motion detection system The motion detection system 1 includes the radio wave sensor 10 described above. The motion detection system 1 also further includes a processing unit 20 and a storage unit 30.

[0028] The radio wave sensor 10 transmits a frequency-modulated radio wave Tr (see Figure 3) from the transmitting antenna, receives a received wave (reflected wave) Re (see Figure 3) which is the transmitted wave Tr reflected by an object, with the receiving antenna, and outputs an intermediate frequency signal (IF signal) obtained by mixing the transmitted wave Tr and the received wave Re.

[0029] The radio wave sensor 10 comprises an oscillator 11, a transmitter 12, a receiver 13, and a mixer 14.

[0030] The oscillator 11 periodically generates a transmission signal modulated using, for example, a frequency-modulated continuous wave (FMCW) method. Specifically, the oscillator 11 periodically generates a transmission signal that is frequency-modulated such that the frequency continuously increases from f0 to f1 over a predetermined chirp time Tc.

[0031] The transmitting unit 12 outputs the transmission signal generated by the oscillator 11 to the transmitting antenna, causing the transmitting antenna to transmit a transmission wave Tr (see Figure 3). The frequency of the transmission wave Tr increases continuously from f0 to f1 over a predetermined chirp time Tc.

[0032] The receiving unit 13 receives the received wave Re (see Figure 3) reflected by an object with a receiving antenna, converts the received wave Re into an electrical signal, and outputs the resulting received signal to the mixer 14. The receiving unit 13 also has a function to measure the signal strength of the received wave Re received by the receiving antenna. The radio wave sensor 10 outputs the measurement result of the signal strength of the received wave Re measured by the receiving unit 13 to the processing unit 20.

[0033] Mixer 14 generates an intermediate frequency signal (IF signal) by mixing the transmission signal generated by oscillator 11 and the reception signal output by receiver 13. The IF signal is generated during the period when the transmission wave Tr is being transmitted and the reception wave Re is being received (i.e., from the start of reception of reception wave Re to the end of transmission of transmission wave Tr). The IF signal is a signal that indicates the frequency difference Δf (see Figure 3) between the transmission wave Tr and the reception wave Re. The IF signal is a signal that indicates the difference between the frequency of the transmission wave Tr and the frequency of the reception wave Re at time t, but if the object reflecting the transmission wave Tr is stationary, the IF signal will be a constant value.

[0034] Generally, to determine the three-dimensional position of an object (moving object) to be detected, the radio wave sensor 10 needs to have, for example, one transmitting antenna and three or more receiving antennas. In this embodiment, the radio wave sensor 10 has one transmitting antenna and three receiving antennas. When the radio wave sensor 10 has three receiving antennas, an IF signal is generated by mixing the received signal received by each of the three receiving antennas with the transmitted signal generated by the oscillator 11. Therefore, each time the radio wave sensor 10 performs a transmit / receive operation during each of the multiple detection periods, it outputs three IF signals corresponding to the three receiving antennas. The positions of the one transmitting antenna and the three receiving antennas of the radio wave sensor 10 are known, and the position information of the one transmitting antenna and the three receiving antennas is stored in advance in the storage unit 30. When the radio wave sensor 10 has multiple antennas (including transmitting and receiving antennas), the multiple antennas may be housed in one housing 2 or arranged in multiple locations.

[0035] The processing unit 20 primarily consists of a computer system having one or more processors and memory. The functions of the processing unit 20 are realized when the processor of the computer system executes a program stored in the memory of the computer system. The program may be stored in memory, provided via a telecommunication line such as the Internet, or provided on a non-temporary recording medium such as a memory card.

[0036] The processing unit 20 has the functions of the detection unit 22 described above. In this embodiment, the processing unit 20 also has the functions of the acquisition unit 21 and the load control unit 23. Note that the acquisition unit 21, the detection unit 22, and the load control unit 23 merely represent functions realized by the processing unit 20 and do not necessarily represent an actual physical configuration.

[0037] The storage unit 30 includes, for example, RAM (Random Access Memory), ROM (Read-Only Memory), and EEPROM (Electrically Erasable Programmable Read-Only Memory). The storage unit 30 stores, for example, the program executed by the processing unit 20. The storage unit 30 also stores the calculation results of the processing unit 20 (for example, the time difference obtained by the detection unit 22, and the integrated value of the time difference), a threshold value to be compared with the integrated value, and so on.

[0038] The acquisition unit 21 acquires an output signal from the radio wave sensor 10. In this embodiment, the acquisition unit 21 acquires an IF signal as an output signal from the radio wave sensor 10. For example, if the radio wave sensor 10 has three receiving antennas, the acquisition unit 21 acquires three IF signals from the radio wave sensor 10, corresponding to each of the three receiving antennas, for each of the multiple detection periods. The acquisition unit 21 also acquires the measurement results of the signal strength of the received wave Re received by each of the three receiving antennas from the radio wave sensor 10 for each of the multiple detection periods.

[0039] The detection unit 22 applies an FFT (Fast Fourier Transform) to the IF signal acquired by the acquisition unit 21 from the radio wave sensor 10 to obtain the frequency spectrum, and acquires the frequency spectrum as an FFT result. In this embodiment, since the radio wave sensor 10 is equipped with three receiving antennas, the mixer 14 outputs three IF signals between the transmitting wave Tr and the three receiving waves Re received by the three receiving antennas, respectively. Therefore, each time the radio wave sensor 10 performs a transmit / receive operation, the detection unit 22 calculates a group of FFT results including three FFT results (frequency spectra) obtained by applying an FFT to each of the three IF signals, and stores the calculated group of FFT results in the storage unit 30. Here, the group of FFT results obtained in one transmit / receive operation of the transmitting wave Tr and the receiving wave Re includes three FFT results (frequency spectra) obtained by applying an FFT to each of the three IF signals corresponding to the three receiving antennas.

[0040] The radio wave sensor 10 repeats transmission and reception operations at a predetermined period T1. The predetermined period T1 is, for example, 200 mS. The radio wave sensor 10 performs transmission and reception operations at a frequency of once per frame Fr, for example, with one frame Fr being 200 mS (see Figure 4). Here, one frame Fr is the detection period during which the radio wave sensor 10 performs one transmission and reception operation, and the radio wave sensor 10 performs transmission and reception operations in each of multiple detection periods (frames Fr). Note that the duration of one frame Fr is not limited to 200 mS and can be changed as appropriate.

[0041] The process by which the detection unit 22 calculates the detection distance between an object and the radio wave sensor 10 based on two output signals output from the radio wave sensor 10 in two frames FrA and FrB (in other words, two detection periods) will be explained with reference to Figures 4 to 11.

[0042] Figure 4 shows the transmitted wave Tr transmitted by the transmitter 12 in frames FrA and FrB. Figures 5 and 6 show the FFT results (relationship between frequency f and signal strength amp of the received wave Re) obtained by FFT processing the IF signal generated by mixing the transmitted signal and the received signal received by one of the three receiving antennas. Figure 5 shows the FFT result for frame FrA, and Figure 6 shows the FFT result for frame FrB. Here, the multiple peaks appearing in the FFT result (frequency spectrum) correspond to the reflection points of objects that reflected the transmitted wave Tr. The detection unit 22 then calculates the time difference, which is the difference between the frequency spectrum in frame FrA and the frequency spectrum in frame FrB, and thereby obtains the time difference, which is the difference in the output signal. By calculating the time difference between the frequency spectrum in frame FrA and the frequency spectrum in frame FrB, the detection unit 22 can remove the frequency components corresponding to stationary objects and obtain only the frequency components corresponding to moving objects. Figure 7 shows the time difference between the frequency spectrum at frame FrA and the frequency spectrum at frame FrB. The peaks in the frequency spectrum shown in Figure 7 correspond to moving objects.

[0043] Here, the detection unit 22 outputs three IF signals between the transmitted wave Tr and the three received waves Re received by the three receiving antennas each time the radio wave sensor 10 performs a transmit / receive operation. By processing each of the three IF signals with FFT, the detection unit 22 obtains three frequency spectra. Then, by calculating the time difference of the three frequency spectra between two different frames, the detection unit 22 can determine the distance from each of the three receiving antennas to the moving object, and thus determine the three-dimensional position of the moving object using three-point positioning.

[0044] In this embodiment, the detection unit 22 calculates the frequency spectrum of the output signal for each of the multiple detection periods (frames Fr), and determines the time difference between the frequency spectrum obtained in the current frame Fr and the frequency spectrum obtained in the previous frame Fr (see Figures 8 and 10). The detection unit 22 then uses the time difference calculation result obtained in the current frame and the time difference calculation result obtained in the previous frame to calculate the integrated value of multiple time differences. For example, the detection unit 22 obtains the integrated value Sa of time differences by adding up to a predetermined number of time differences up to the current frame. The detection unit 22 then stores the time difference calculation result obtained in the current frame Fr and the integrated value Sa of multiple time differences in the storage unit 30.

[0045] The detection unit 22 compares the cumulative value Sa obtained in this way with the threshold Th1 (see Figure 9). Even if a person in the detection target space SP1 is standing still or sitting in a chair, if they are making small movements such as breathing, the cumulative value Sa obtained by the detection unit 22 will gradually increase and eventually become equal to or greater than the threshold Th1. Therefore, when the cumulative value Sa becomes equal to or greater than the threshold Th1, the detection unit 22 outputs a detection result indicating that a person is present in the detection target space SP1.

[0046] In this way, the detection unit 22 calculates the integrated value Sa of the time difference and detects the presence or absence of a moving object by comparing the integrated value Sa of the time difference with the threshold Th1, thereby increasing the sensitivity of object detection. For example, when the detection unit 22 detects an object from a single time difference, the diameter of the area in which the movement of an object of about 1 mm can be detected (a circular area centered directly below the radio wave sensor 10) is about 4 m. In contrast, as in this embodiment, when the detection unit 22 detects an object based on the integrated value of multiple time differences, the diameter R1 (see Figure 2) of the area in which the movement of an object of about 1 mm can be detected (a circular area centered directly below the radio wave sensor 10) can be expanded to about 5 m, thereby realizing a highly sensitive motion detection system 1.

[0047] On the other hand, when a person who was present in the detection target space SP1 moves outside of the detection target space SP1, the cumulative value Sa calculated by the detection unit 22 gradually decreases, and even if the cumulative value Sa is temporarily above the threshold Th1, the cumulative value Sa will eventually fall below the threshold Th1. Therefore, when the cumulative value Sa falls below the threshold Th1, the detection unit 22 outputs a detection result indicating that no person is present in the detection target space SP1.

[0048] Furthermore, when the detection unit 22 detects the presence of a person in the detection target space SP1, it calculates the distance from the three receiving antennas to the person based on the frequency spectrum obtained for each of the three IF signals in the current frame. The detection unit 22 may then determine the three-dimensional position of the person using the principle of triangulation based on the calculation result of the distance from the three receiving antennas to the person.

[0049] If a person is present in the detection target space SP1, the transmitted wave Tr from the transmitter 12 will be reflected by multiple parts (reflection points) of the person's body. The multiple reflected waves reflected by the multiple reflection points are received by the receiver 13, and the mixer 14 outputs an output signal (IF signal) which is a mixture of the multiple reflected waves received by the receiver 13 and the transmitted wave. In other words, the radio wave sensor 10 outputs an output signal based on the reflected wave (received wave Re) reflected by each of the multiple reflection points on the surface of the object and the transmitted wave Tr. When the detection unit 22 applies FFT processing to the output signal from the radio wave sensor 10, multiple peaks corresponding to the multiple reflection points appear in the FFT result (frequency spectrum) of the output signal. The detection unit 22 then calculates the time difference for the multiple peaks corresponding to the multiple reflection points and integrates the time differences. One or more reflection points where the integrated value Sa of the time differences is greater than or equal to the threshold Th1 are acquired as reflection points of a moving object. In other words, the detection unit 22 acquires the distribution of one or more reflection points from among a plurality of reflection points whose integrated value is equal to or greater than a threshold.

[0050] Figure 11 is a diagram plotted on a three-dimensional space 500 representing the room 400, showing multiple points DT1 corresponding to multiple reflection points where the integrated value Sa is greater than or equal to the threshold Th1, when the detection unit 22 detects a person 300 present in the detection target space SP1. When the radio wave sensor 10 is installed on the ceiling 401, the transmitted wave Tr is reflected a lot from the head, shoulders, hands, and feet of the person 300, while reflection of the transmitted wave Tr is less likely to occur from the torso of the person 300. Therefore, multiple points DT1 representing multiple reflection points from the head, shoulders, hands, and feet of the person 300 are plotted on the three-dimensional space 500.

[0051] Here, the detection unit 22 performs clustering on the multiple points DT1 corresponding to each of the multiple reflection points, thereby grouping the multiple points DT1 into one or more clusters. In the example in Figure 11, the multiple points DT1 representing the multiple reflection points are grouped into two clusters: cluster CL1 corresponding to the head, shoulders, hands, etc., of person 300, and cluster CL2 corresponding to the feet of person 300. As shown in Figure 11, when the multiple points DT1 corresponding to person 300 are grouped into two clusters CL1 and CL2, the detection unit 22 can determine the location of person 300 by, for example, determining the centroid position of each of the clusters CL1 and CL2, and then determining the midpoint of the two centroid positions. In other words, the detection unit 22 can determine the location of person 300 based on the distribution of one or more reflection points whose integrated value Sa is greater than or equal to the threshold Th1.

[0052] In this way, when multiple points DT1 representing person 300 are grouped into multiple clusters, the detection unit 22 determines the centroid position of each cluster and detects the midpoint of the centroid positions of the clusters as the three-dimensional position of the object. The detection unit 22 then determines the distance between the midpoint of the centroid positions of the clusters and the radio wave sensor 10 as the detected distance between the object and the radio wave sensor 10. If multiple points DT1 representing person 300 are detected as a single cluster, the detection unit 22 only needs to detect the centroid position of the cluster as the three-dimensional position of the object and determine the distance between the centroid position of the cluster and the radio wave sensor 10 as the detected distance between the object and the radio wave sensor 10.

[0053] Furthermore, the detection unit 22 determines the distribution of one or more reflection points whose integrated value Sa is equal to or greater than the threshold Th1, and detects the movement of an object corresponding to one or more reflection points based on the temporal displacement of this distribution. When an object (e.g., a person) in the detection target space SP1 moves, the distribution of one or more reflection points whose integrated value Sa is equal to or greater than the threshold Th1 also changes in accordance with the movement of the object. Therefore, the detection unit 22 can detect the movement of an object in the detection target space SP1 by detecting the movement of the distribution of one or more reflection points whose integrated value Sa is equal to or greater than the threshold Th1.

[0054] The load control unit 23 executes control processing for load 3 according to the detection result of the detection unit 22. If the detection unit 22 detects that a person is present in the detection target space SP1, the load control unit 23 supplies power to the lighting load, which is load 3, and turns on the lighting load. If the detection unit 22 detects that no person is present in the detection target space SP1, the load control unit 23 cuts off the power supply to the lighting load, which is load 3, and turns off the lighting load. The load control unit 23 will be explained in more detail in "(2.1.2) Wiring Devices".

[0055] (2.1.2) Wiring devices As described above, the wiring device 100 comprises a motion detection system 1 and a load control unit 23. The wiring device 100 further comprises a load connection unit 50, a drive circuit 40, and a switch element 41. In this embodiment, the housing 2 of the motion detection system 1 houses the radio wave sensor 10, the processing unit 20, the storage unit 30, the load connection unit 50, the drive circuit 40, and the switch element 41. In other words, in this embodiment, the functions of the motion detection system 1 and the functions of the wiring device 100 are housed in a single housing 2. Furthermore, the wiring device 100 of this embodiment and the load 3, which is the control target of the load control unit 23, constitute the load system 200.

[0056] The load connection section 50 includes a pair of connection terminals 51 and 52. A series circuit of an AC power supply AC and a load 3 is connected between the pair of connection terminals 51 and 52 via electric wires W1 and W2. The load 3 is, for example, a lighting load. The lighting load 3 has a light source such as an LED (Light Emitting Diode) and a lighting circuit for turning on the light source.

[0057] The switching element 41 is, for example, a semiconductor switching element such as a triac, thyristor, FET (Field effect transistor), or bipolar transistor, or a relay. The switching element 41 is connected between a pair of connection terminals 51 and 52. In other words, a series circuit of the AC power supply AC and the load 3 is connected between both ends of the switching element 41. When the switching element 41 becomes conductive and power is supplied to the load 3, the lighting load 3 lights up. Conversely, when the switching element 41 becomes non-conductive and the power supply to the load 3 is cut off, the lighting load 3 turns off.

[0058] The drive circuit 40 controls the switch element 41 to a conductive or non-conductive state in accordance with the control signal input from the load control unit 23.

[0059] When the detection unit 22 detects the presence of a person, the load control unit 23 outputs a control signal to the drive circuit 40, controlling the switch element 41 to a conductive state, thereby turning on the load 3, which is a lighting load. Conversely, when the detection unit 22 detects the absence of a person, the load control unit 23 outputs a control signal to the drive circuit 40, controlling the switch element 41 to a non-conductive state, thereby turning off the load 3, which is a lighting load.

[0060] Furthermore, if the lighting load, which is load 3, has a dimming function, the load control unit 23 may dim the lighting load, which is load 3, according to the detection result of the detection unit 22. That is, if the detection unit 22 detects the presence of a person, the load control unit 23 may turn on the lighting load, which is load 3, at a first brightness level, and if the detection unit 22 detects the absence of a person, the load control unit 23 may turn on the lighting load, which is load 3, at a second brightness level that is dimmer than the first brightness level. As a result, when there is no person in the detection target space SP1, the brightness of the lighting load, which is load 3, can be controlled to be dimmer than when there is a person, and the power consumption of the lighting load can be reduced.

[0061] For example, the load control unit 23 may output a control signal to the drive circuit 40 for phase control of the switch element 41. The drive circuit 40 controls the switch element 41 to a conductive state for a conduction period corresponding to the control signal during each half-cycle of the AC voltage input from the AC power supply, thereby adjusting the power supplied to the load 3, which is a lighting load, and enabling dimming of the lighting load.

[0062] (2.2) Operation Instructions The operation of the wiring device 100 equipped with the motion detection system 1 of the above embodiment will be explained with reference to Figure 12 and the like. Note that the flowchart shown in Figure 12 is merely one example of the motion detection method according to this embodiment, and the order of processing may be changed as appropriate, or processing may be added or omitted as appropriate.

[0063] The radio wave sensor 10 performs transmission and reception operations in each of the multiple detection periods (frames) and outputs an output signal (IF signal), and the acquisition unit 21 acquires the output signal output from the radio wave sensor 10 in each detection period (S1).

[0064] When the acquisition unit 21 acquires an output signal (IF signal) from the radio wave sensor 10, the detection unit 22 performs FFT processing on the output signal (IF signal) of the radio wave sensor 10 to calculate the FFT result (frequency spectrum) and stores the FFT result in the storage unit 30. The detection unit 22 then calculates the time difference, which is the difference between the FFT result calculated in the current frame and the FFT result calculated in the previous frame, and stores the calculated time difference DS in the storage unit 30 (S2). The detection unit 22 also uses the previous time difference DS calculation result stored in the storage unit 30 and the time difference DS calculation result calculated in step S2 to calculate the integrated value Sa of the time difference DS over a predetermined integration period (S3). The detection unit 22 stores the integrated value Sa calculated in step S3 in the storage unit 30.

[0065] Next, the detection unit 22 compares the cumulative value Sa obtained in step S3 with the threshold Th1 (S4).

[0066] If the cumulative value Sa in the comparison process in step S4 is greater than or equal to the threshold Th1 (S4: Yes), the detection unit 22 determines that a person is present in the detection target space SP1 and outputs a presence detection signal to the load control unit 23. When the load control unit 23 receives the presence detection signal from the detection unit 22, it outputs an ON control signal to the drive circuit 40. When the drive circuit 40 receives the ON control signal from the load control unit 23, it controls the switch element 41 to a conductive state and supplies power to the lighting load, which is load 3, to turn on the lighting load (S5).

[0067] On the other hand, if the cumulative value Sa in the comparison process in step S4 is less than the threshold Th1 (S4: No), the detection unit 22 determines that no person is present in the detection target space SP1 and outputs an absence detection signal to the load control unit 23. When the load control unit 23 receives the absence detection signal from the detection unit 22, it outputs an off control signal to the drive circuit 40. When the drive circuit 40 receives the off control signal from the load control unit 23, it controls the switch element 41 to a non-conductive state, cuts off the power supply to the lighting load, which is load 3, and turns off the lighting load (S6).

[0068] (3) Variant The above embodiments are merely one of many embodiments of this disclosure. The above embodiments can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure can be achieved. Furthermore, functions similar to those of the motion detection system 1 may be embodied in a motion detection method, a computer program, a non-temporary recording medium on which the program is recorded, or a computer program product including the program. A motion detection method according to one embodiment includes an acquisition process and a detection process. In the acquisition process, an output signal output from the radio wave sensor 10 for each detection period is acquired. In each of the multiple detection periods, the radio wave sensor 10 transmits a transmission wave, which is a frequency-modulated radio wave, to the detection target space SP1, and when it receives a reflected wave that has been reflected by an object in the detection target space SP1, it outputs an output signal based on the transmission wave and the reflected wave. In the detection process, a difference calculation process is performed multiple times to find the time difference of the output signals in the difference calculation period between two detection periods by calculating the difference between two output signals output by the radio wave sensor 10 in two different detection periods. In the detection process, an integrated value Sa is obtained by accumulating the time difference calculation results over multiple different difference calculation periods, and the presence or absence of a moving object is detected based on the comparison result obtained by comparing the integrated value Sa with a threshold Th1. A (computer) program according to one embodiment is a program for causing one or more processors to execute the above motion detection method.

[0069] The following lists some modifications of the above embodiment. The modifications described below can be combined and applied as appropriate.

[0070] The entity that executes the motion detection system 1 and motion detection method in this disclosure includes a computer system. The computer system mainly consists of a processor and memory as hardware. The functions of the motion detection system 1 in this disclosure are realized by the processor executing a program recorded in the memory of the computer system. The program may be pre-recorded in the memory of the computer system, provided via a telecommunications line, or provided on a non-temporary recording medium such as a memory card, optical disk, or hard disk drive that can be read by the computer system. The processor of the computer system consists of one or more electronic circuits including semiconductor integrated circuits (ICs) or large-scale integrated circuits (LSIs). The integrated circuits such as ICs and LSIs referred to here are named differently depending on the degree of integration, and include integrated circuits called system LSIs, VLSIs (Very Large Scale Integration), or ULSIs (Ultra Large Scale Integration). Furthermore, FPGAs (Field-Programmable Gate Arrays) that are programmed after the manufacture of LSIs, or logic devices that allow for the reconfiguration of junction relationships or circuit compartments within LSIs, can also be used as processors. Multiple electronic circuits may be integrated onto a single chip or distributed across multiple chips. Multiple chips may be integrated onto a single device or distributed across multiple devices. The computer system referred to here includes a microcontroller having one or more processors and one or more memories. Therefore, the microcontroller also consists of one or more electronic circuits, including semiconductor integrated circuits or large-scale integrated circuits.

[0071] Furthermore, it is not essential for the motion detection system 1 to have multiple functions integrated into a single housing 2, and the components of the motion detection system 1 may be distributed across multiple housings. Similarly, it is not essential for the wiring device 100 to have multiple functions integrated into a single housing 2, and the components of the wiring device 100 may be distributed across multiple housings.

[0072] In the above embodiment, where "greater than or equal to" is used in the comparison of the magnitudes of two values, it may also be used as "greater than." In other words, whether or not the case where the two values ​​are equal is included in the comparison of two values ​​can be arbitrarily changed depending on the setting of the reference value, etc., so there is no technical difference between "greater than or equal to" and "greater than." Similarly, where "less than" is used, it may also be used as "less than or equal to."

[0073] The method by which the detection unit 22 calculates the integrated value of the time difference is not limited to the calculation method described in the above embodiment (a method of accumulating the time difference over a predetermined accumulation period up to the current frame). The detection unit 22 may calculate the integrated value in the following way. Here, if the calculation result of the time difference obtained in the current frame is DS, the integrated value of the time difference obtained in the previous frame is Sb, and a predetermined constant subtraction value is M1, the detection unit 22 may calculate the integrated value Sa in the current frame using the calculation formula in equation (1) below. Sa = DS + Sb - M1 …(1)

[0074] The subtraction value M1 is set to a value smaller than the time difference caused by minute movements of a person (for example, breathing or shifting). Therefore, even if a person in the detection target space SP1 is standing still or sitting in a chair, if they are making minute movements such as breathing or shifting, the integrated value Sa calculated by the detection unit 22 will gradually increase. On the other hand, if a person who was in the detection target space SP1 moves outside of the detection target space SP1, the detection unit 22 will not be able to detect the person's movement, and the calculation result of the time difference DS will become zero, so the integrated value Sa will gradually decrease.

[0075] In the above embodiment, the housing 2 of the wiring device 100 is located on the underside of the ceiling 401, but the housing 2 of the wiring device 100 may also be located on the wall 402 of the room 400. In this case, the radio wave sensor 10 only needs to be mounted on the housing 2 so as to transmit radio waves in the direction normal to the wall 402 on which the housing 2 is located, and it can detect objects present in the interior space of the room 400.

[0076] In the above embodiment, the motion detection system 1 is provided in the wiring device 100, but it may also be provided in a load system 200 such as a lighting device. The lighting device includes a main body that houses a light source and a lighting circuit for the light source, and the motion detection system 1 is housed inside the main body. The lighting circuit controls the operating state of the light source (e.g., on, off, dimming, etc.) according to the detection result of the motion detection system 1. Note that the load system 200 is not limited to a lighting device, but may also be an air conditioning device such as a ventilation fan or an air conditioner.

[0077] In the above embodiment, the radio wave sensor 10 is equipped with one transmitting antenna and three receiving antennas, but the number of receiving antennas may be two or four or more.

[0078] Furthermore, in the radio wave sensor 10, the antenna used for transmitting the transmitting wave Tr and the antenna used for receiving the receiving wave Re may be the same antenna (hereinafter referred to as the "common antenna"). In other words, the transmitting wave Tr may be transmitted from the common antenna, and the receiving wave Re corresponding to the transmitting wave Tr may be received by the same common antenna.

[0079] In the above embodiment, one transmission / reception operation is performed in one frame Fr, but multiple transmission / reception operations may be performed in one frame Fr. In that case, the detection unit 22 can detect the presence or absence of a moving object based on a representative value (e.g., an average value) of the IF signal output from the radio wave sensor 10 during multiple transmission / reception operations.

[0080] Alternatively, the motion detection system 1 may be housed in a separate enclosure and output the motion detection result to a wiring device 100 or a load system 200 (e.g., a lighting device).

[0081] (summary) Based on the embodiments described above, the following aspects are disclosed.

[0082] The first embodiment of the motion detection system (1) comprises a radio wave sensor (10) and a detection unit (22). The radio wave sensor (10) transmits a frequency-modulated radio wave, which is a transmitted wave, to the detection target space (SP1) during each of a plurality of detection periods. When it receives a reflected wave that has been reflected by an object present in the detection target space (SP1), it outputs an output signal based on the transmitted wave and the reflected wave. The detection unit (22) performs a difference calculation process multiple times to determine the time difference of the output signals during the difference calculation period between two detection periods by calculating the difference between two output signals output by the radio wave sensor (10) during two different detection periods. The detection unit (22) obtains an integrated value (Sa) by accumulating the calculation results of the time differences in a plurality of different difference calculation periods, and detects the presence or absence of a moving object based on the comparison result obtained by comparing the integrated value (Sa) with a threshold (Th1).

[0083] According to this embodiment, even when the magnitude of the time difference between the two output signals is small, the detection unit (22) can increase the value of the integrated value (Sa) by calculating an integrated value (Sa) by accumulating the results of multiple time difference calculations. Therefore, the detection unit (22) can more easily detect moving objects even when the movement of objects in the detection target space (SP1) is minute, and can improve the sensitivity for detecting moving objects.

[0084] In the second embodiment of the motion detection system (1), in the first embodiment, the radio wave sensor (10) outputs an output signal based on the reflected wave reflected at each of a plurality of reflection points on the surface of an object and the transmitted wave. The detection unit (22) acquires the distribution of one or more reflection points among the plurality of reflection points whose integrated value (Sa) is equal to or greater than a threshold (Th1).

[0085] According to this embodiment, the position of a moving object can be determined based on the distribution of one or more reflection points.

[0086] In the third embodiment of the motion detection system (1), in the second embodiment, the detection unit (22) detects the movement of an object corresponding to one or more reflection points based on the temporal displacement of the distribution.

[0087] According to this embodiment, the detection unit (22) can detect the movement of an object based on the temporal displacement of the distribution of one or more reflection points.

[0088] The fourth embodiment of the motion detection system (1) further comprises a housing (2) in any of the first to third embodiments. The housing (2) houses a radio wave sensor (10) and is positioned on a wall (402) next to the space to be detected (SP1) or on the ceiling (401) above the space to be detected (SP1).

[0089] According to this embodiment, the presence or absence of an object in the target space (SP1) can be detected using a radio wave sensor (10) housed in a housing (2) positioned on a wall (402) or ceiling (401).

[0090] In the fifth embodiment of the motion detection system (1), in the fourth embodiment, the housing (2) further houses the detection unit (22).

[0091] According to this embodiment, compared to the case where the radio wave sensor (10) and the detection unit (22) are housed in separate enclosures, the installation work for the radio wave sensor (10) and the detection unit (22) can be performed at one time, thereby simplifying the installation work.

[0092] The wiring device (100) of the sixth embodiment comprises a motion detection system (1) of any of the first to fifth embodiments, a load connection section (50), and a load control section (23). A load (3) is connected to the load connection section (50). The load control section (23) controls the operating state of the load (3) connected to the load connection section (50) based on the object detection result by the motion detection system (1).

[0093] According to this embodiment, the sensitivity for detecting moving objects can be improved.

[0094] The seventh embodiment of the load system (200) comprises a motion detection system according to any of the first to fifth embodiments, a load (3), and a load control unit (23). The load control unit (23) controls the operating state of the load (3) based on the object detection result by the motion detection system (1).

[0095] According to this embodiment, the sensitivity for detecting moving objects can be improved.

[0096] The eighth aspect of the motion detection method includes an acquisition process and a detection process. In the acquisition process, an output signal output from a radio wave sensor (10) for each detection period is acquired. In each of the multiple detection periods, the radio wave sensor (10) transmits a frequency-modulated radio wave, which is a transmission wave, to the detection target space (SP1). When it receives a reflected wave that has been reflected by an object present in the detection target space (SP1), it outputs an output signal based on the transmission wave and the reflected wave. In the detection process, a difference calculation process is performed multiple times to determine the time difference in the difference calculation period between two detection periods by calculating the difference between two output signals output by the radio wave sensor (10) in two different detection periods. In the detection process, an integrated value (Sa) is obtained by accumulating the results of multiple time difference calculations in multiple different difference calculation periods, and the presence or absence of a moving object is detected based on the comparison result obtained by comparing the integrated value (Sa) with a threshold (Th1).

[0097] According to this embodiment, the sensitivity for detecting moving objects can be improved.

[0098] The program of the ninth aspect is a program for causing one or more processors to execute the motion detection method of the eighth aspect.

[0099] According to this embodiment, the sensitivity for detecting moving objects can be improved.

[0100] Not limited to the above embodiments, various configurations (including modifications) of the motion detection system (1) according to the above embodiment can be embodied in motion detection methods, (computer) programs, non-temporary recording media on which the program is recorded, or computer program products including the program, etc., which are executed by the motion detection system (1).

[0101] The configurations relating to the second to fifth aspects are not essential to the motion detection system (1) and can be omitted as appropriate. [Explanation of Symbols]

[0102] 1. Motion detection system 2 cabinets 3 load 10 Radio wave sensors 22 Detection unit 23 Load Control Unit 50 Load connection section 100 Wiring Devices 200 load system 401 Ceiling 402 Wall Sa cumulative value SP1 Detection Target Space Th1 threshold

Claims

1. A radio wave sensor that transmits a frequency-modulated radio wave, which is a transmitted wave, to the detection target space during each of multiple detection periods, and when it receives a reflected wave that has been reflected by an object in the detection target space, outputs an output signal based on the transmitted wave and the reflected wave, It comprises a detection unit, The detection unit is The difference calculation process is performed multiple times to determine the time difference of the output signals during the difference calculation period between the two detection periods by calculating the difference between the two output signals output by the radio wave sensor during two different detection periods. The cumulative value is obtained by accumulating the calculation results of the time difference over multiple different difference calculation periods. The presence or absence of the moving object is detected based on the comparison result obtained by comparing the cumulative value and the threshold value. Motion detection system.

2. The radio wave sensor outputs the output signal based on the reflected wave reflected at each of the plurality of reflection points on the surface of the object and the transmitted wave. The detection unit acquires the distribution of one or more of the reflection points among the plurality of reflection points whose integrated value is equal to or greater than the threshold. The motion detection system according to claim 1.

3. The detection unit detects the movement of the object corresponding to the one or more reflection points based on the temporal displacement of the distribution. The motion detection system according to claim 2.

4. The system further comprises a housing for the radio wave sensor, which is positioned on a wall adjacent to the space to be detected, or on the ceiling above the space to be detected. The motion detection system according to claim 1.

5. The housing further houses the detection unit, The motion detection system according to claim 4.

6. A motion detection system according to any one of claims 1 to 5, A load connection section to which the load is connected, The system includes a load control unit that controls the operating state of the load connected to the load connection unit based on the detection result of the object by the motion detection system, Wiring devices.

7. A motion detection system according to any one of claims 1 to 5, Load and The system includes a load control unit that controls the operating state of the load based on the detection result of the object by the motion detection system, Load system.

8. In each of the multiple detection periods, a transmission wave, which is a frequency-modulated radio wave, is transmitted to the detection target space, and when an object present in the detection target space reflects the transmission wave, an acquisition process is performed to acquire the output signal output for each detection period from a radio wave sensor that outputs an output signal based on the transmission wave and the reflected wave. Includes detection processing, In the aforementioned detection process, The difference calculation process is performed multiple times to determine the time difference of the output signals during the difference calculation period between the two detection periods by calculating the difference between the two output signals output by the radio wave sensor during two different detection periods. The cumulative value is obtained by accumulating the calculation results of the time difference over multiple different difference calculation periods. The presence or absence of the moving object is detected based on the comparison result obtained by comparing the cumulative value and the threshold value. Motion detection method.

9. One or more processors are used to perform the motion detection method described in claim 8, program.

Images