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

Abstract

To reduce false detections of mechanical disturbances. [Solution] The motion detection system 1 comprises a radio wave sensor 10 and a detection unit 22. The radio wave sensor 10 transmits a transmission wave, which is a frequency-modulated radio wave, to the detection target space. When the radio wave sensor 10 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 22 calculates a time difference, which is the difference in the intensity of two output signals output by the radio wave sensor 10 during two different detection periods, and detects the presence or absence of a moving object based on the comparison result obtained by comparing the high or low of the time difference with a threshold. The detection unit 22 excludes an object from detection if the temporal change of the moving object is a periodic change and is different from the periodic change associated with human respiration.

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 a 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 not only a person but also a machine such as a fan exists in the detection area, there is a possibility that the swinging motion of the fan is erroneously detected as a human movement.

[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 reducing false detection of mechanical disturbances.

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 transmission wave, which is a frequency-modulated radio wave, to the detection target space. When the radio wave sensor 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 detects the moving object based on the output signal output from the radio wave sensor. The detection unit calculates a time difference, which is the difference between the intensity of two output signals output by the radio wave sensor during two different detection periods, and detects the presence or absence of the moving object based on a comparison result obtained by comparing the time difference with a threshold value. The detection unit excludes the object from detection if the temporal change of the moving object is a periodic change and is different from the periodic change associated with human respiration.

[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 is acquired from a radio wave sensor. The radio wave sensor transmits a transmission wave, which is a frequency-modulated radio 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, the moving object is detected based on the output signal output from the radio wave sensor. In the detection process, a time difference is calculated, which is the difference between the intensity of two output signals output by the radio wave sensor during two different detection periods, and the presence or absence of the moving object is detected based on a comparison result obtained by comparing the high or low of the time difference with a threshold. In the detection process, if the temporal change of the moving object is a periodic change and is different from the periodic change associated with human respiration, the object is excluded from the detection target.

[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] This disclosure provides a motion detection system, wiring device, load system, motion detection method, and program capable of reducing false detection of mechanical disturbances. [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 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 graph showing an example of the time evolution of mechanical disturbances that can be excluded by the motion detection system described above. [Figure 9] Figure 9 is a distribution map showing the distribution of points representing moving objects detected by the motion detection system described above. [Figure 10] Figure 10 is a flowchart illustrating the operation of the wiring device mentioned above. [Modes for carrying out the invention]

[0013] The motion detection system, wiring device, load system, and motion detection method according to the embodiments will be described in detail below with reference to the drawings. However, the figures described in the following embodiments are schematic diagrams, and the dimensional ratios of the sizes 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 Figure 1, the motion detection system 1 according to this embodiment includes a radio wave sensor 10 and a detection unit 22.

[0015] The radio wave sensor 10 transmits a frequency-modulated radio wave, which is the transmitted wave, to the detection target space SP1 (see Figure 2). 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 transmitted wave and the reflected wave.

[0016] The detection unit 22 detects a moving object based on the output signal output from the radio wave sensor 10. The detection unit 22 calculates a time difference, which is the difference between two output signal intensities respectively output by the radio wave sensor 10 in two different detection periods, and detects the presence or absence of a moving object based on a comparison result of comparing the time difference with a threshold value. When the temporal change of the moving object is a periodic change and is different from the periodic change associated with human breathing, the detection unit 22 excludes the object from the detection target. Note that the "time difference, which is the difference between output signal intensities" as referred to in the present disclosure includes not only the "time difference value of the output signal intensities" but also the "time difference value corresponding to the time difference value of the output signal intensities". Therefore, the "time difference, which is the difference between output signal intensities" may include, for example, a time difference value proportional to the time difference value of the output signal intensities.

[0017] The moving object detection system 1 of the present embodiment detects a moving object (hereinafter, may also be referred to as a "moving body"). In the present embodiment, the detection target of the moving object detection system 1 is, for example, a person. The detection target space SP1 in which the moving object detection system 1 detects the presence or absence of an object is a space where a person may exist, for example, the internal space of a residential or non-residential building used by a person. The magnitude (intensity) of the output signal output by the radio wave sensor 10 is a magnitude proportional to the distance from the radio wave sensor 10 to the object. Therefore, the time difference between the two output signal intensities respectively output by the radio wave sensor 10 in two detection periods is a magnitude proportional to the amount of movement of the object during the two detection periods. When the moving object detection system 1 detects a moving object in the detection target space SP1, it determines that this object is a person.

[0018] However, the detection target space SP1 may contain objects other than people 300 that may be moving. For example, in the room 400 shown in Figure 2, there is a fan 302 placed on a desk 301. In such a case, the oscillating motion of the fan 302 may be mistakenly detected as human movement. For example, if load 3 is a lighting load, a misdetection of machine movement other than a person will result in continued false illumination. Here, the temporal displacement of the fan 302 during oscillating motion changes periodically, but this is clearly different from the periodic changes associated with human breathing.

[0019] Therefore, the motion detection system 1 of this embodiment treats any temporal changes of a moving object that are periodic and different from the periodic changes associated with human respiration as "mechanical disturbances." If the detection unit 22 detects that the temporal changes of an object are periodic and different from the periodic changes associated with human respiration, it excludes that object from detection. Thus, the motion detection system 1 of this embodiment makes it possible to reduce malfunctions of the load 3 due to false detection of mechanical disturbances. The load 3 will be explained in more detail in "(2.1.2) Wiring Devices."

[0020] (2) Details The motion detection system 1 of this embodiment is used to detect moving objects using a radio wave sensor 10.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] (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 10.

[0025] (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.

[0026] The radio wave sensor 10 transmits a frequency-modulated radio wave, Tr (see Figure 3), from its transmitting antenna, and receives a received wave (reflected wave) Re (see Figure 3) that is formed when the transmitted wave Tr is reflected by an object, using its receiving antenna. The radio wave sensor 10 then outputs an intermediate frequency signal (IF signal) obtained by mixing the transmitted wave Tr and the received wave Re.

[0027] The radio wave sensor 10 comprises an oscillator 11, a transmitter 12, a receiver 13, and a mixer 14.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] The storage unit 30 includes memory. The memory is, 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 calculation result of the time difference obtained by the detection unit 22, time-series data of the time difference, etc.), thresholds to be compared with the time difference, etc.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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 7.

[0040] 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 output signal strength. 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.

[0041] Here, the radio wave sensor 10 outputs three IF signals each time it performs a transmit / receive operation, between the transmitted wave Tr and the three received waves Re received by the three receiving antennas. The detection unit 22 obtains three frequency spectra by performing an FFT on each of the three IF signals. Then, the detection unit 22 can determine the distance from each of the three receiving antennas to the moving object by calculating the time difference of the three frequency spectra between two different frames, and can determine the three-dimensional position of the moving object using three-point positioning.

[0042] The detection unit 22 compares the calculated time difference, which is the difference between the frequency spectrum of the previous frame and the frequency spectrum of the current frame, with the threshold Th1 (see Figure 7). If the calculated time difference is greater than or equal to the threshold Th1, the detection unit 22 outputs a detection result indicating that an object exists in the detection target space SP1. In this way, the detection unit 22 can detect the presence or absence of a moving object by calculating the time difference and comparing the calculated time difference with the threshold Th1.

[0043] Furthermore, when the detection unit 22 detects the presence of an object in the detection target space SP1, it calculates the distance from the three receiving antennas to the object 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 object using the principle of triangulation based on the calculation result of the distance from the three receiving antennas to the object.

[0044] If an object is present in the detection target space SP1, the transmitted wave Tr from the transmitter 12 will be reflected at multiple points (reflection points) on the object. The multiple reflected waves reflected at 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 waves (received waves Re) reflected at 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 acquires one or more reflection points for which the calculated time difference is greater than or equal to the threshold Th1 as reflection points of a moving object. Hereinafter, points on the surface of an object for which the calculated time difference is greater than or equal to the threshold Th1 may be referred to as "moving points". In other words, the detection unit 22 acquires the distribution of one or more reflection points (moving points) from among a plurality of reflection points, the time difference calculation result of which is greater than or equal to the threshold Th1. The detection unit 22 can then detect moving objects corresponding to the distribution of one or more reflection points (moving points).

[0045] Figure 9 shows a plot of multiple moving points DT1 on a three-dimensional space 500 representing the room 400, corresponding to multiple reflection points whose time difference calculation result 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 moving 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.

[0046] Here, the detection unit 22 performs clustering on multiple moving points DT1 corresponding to multiple reflection points, thereby grouping the multiple moving points DT1 into one or more clusters. In the example in Figure 9, the multiple moving points DT1 representing 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 9, when the multiple moving points DT1 corresponding to person 300 are grouped into two clusters, CL1 and CL2, the detection unit 22, for example, finds the centroid position of each of clusters CL1 and CL2, and then finds the midpoint of the two centroid positions. This allows the detection unit 22 to determine the location of person 300. In other words, the detection unit 22 can determine the location of person 300 based on the distribution of one or more reflection points (moving points) whose time difference calculation result is greater than or equal to the threshold Th1.

[0047] In this way, when multiple moving 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 moving 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.

[0048] Furthermore, the detection unit 22 determines the distribution of one or more reflection points (moving points) whose time difference calculation result is greater than or equal to the threshold Th1, and detects the movement of an object corresponding to one or more reflection points (moving 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 time difference calculation result is greater than or equal to 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 time difference calculation result is greater than or equal to the threshold Th1.

[0049] 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".

[0050] By the way, in the detection target space SP1 of this embodiment, as shown in Figure 2, there is a fan 302 that may move in addition to the person 300. In such a case, the detection unit 22 may mistakenly detect the oscillating motion of the fan 302 as the movement of a person. For example, if the load 3 is a lighting load, a erroneous detection of the movement of a machine other than a person will result in continued false illumination.

[0051] Figure 8 plots the sum of the time difference calculation results for one or more moving points among the multiple reflection points reflected by the fan 302, where the calculated time difference of the output signal intensity is equal to or greater than the threshold Th1, on a time axis.

[0052] The graph in Figure 8 represents the time change of a value proportional to the level of the reflected signal reflected at the reflection point (moving point) on the surface of the fan 302. As shown in Figure 8, the level of the reflected signal at the moving point changes periodically due to the oscillating motion of the fan 302. In other words, the time change of the moving point due to the oscillating motion of the fan 302 is a repeating periodic change. The period t13 (hereinafter sometimes referred to as the mechanical period) of the periodic change in the oscillating motion of the fan 302 is, for example, 10 to 20 seconds. The mechanical period can generally be set as appropriate.

[0053] In contrast, the movements associated with human respiration are also periodic. Hereafter, we will refer to the periodicity of these movements as the "respiratory cycle." Generally, the human respiratory cycle is between 3 and 5 seconds. In other words, the number of breaths per minute is between 12 and 20.

[0054] In this embodiment, in order to distinguish between the movement of an object due to mechanical disturbances and the movement associated with a person's breathing, the detection unit 22 detects whether the temporal change in the distribution of one or more moving points is a repeating periodic change. More specifically, for one or more moving points whose time difference calculation result is greater than or equal to a threshold Th1, the detection unit 22 performs the process of calculating the time difference multiple times over two different detection periods. The detection unit 22 detects a periodic change from the time-series data of the multiple time difference calculation results and calculates the period T of that periodic change.

[0055] The detection unit 22 then excludes the distribution of one or more moving points from detection if the period of the detected periodic change differs from the respiratory cycle. More specifically, the detection unit 22 stores the region where the one or more moving points (objects) excluded from detection exist as an excluded region, and excludes the excluded region from detection from the next time onward.

[0056] (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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] (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 10 and the like. Note that the flowchart shown in Figure 10 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.

[0064] 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).

[0065] 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 time difference calculation result DS in the storage unit 30 (S2).

[0066] Next, the detection unit 22 compares the calculated time difference DS obtained in step S2 with the threshold Th1. If the calculated time difference DS is greater than or equal to the threshold Th1 in the comparison process, the detection unit 22 detects a periodic change in the time difference (S3). More specifically, for objects (one or more moving points) whose calculated time difference DS is greater than or equal to the threshold Th1 in the comparison process, the detection unit 22 performs the process of calculating the time difference multiple times over two different detection periods. Then, the detection unit 22 detects a periodic change from the time-series data of the multiple time difference calculation results and calculates the period T of that periodic change.

[0067] Next, the detection unit 22 compares the period T of the periodic time change of the time difference with the respiratory cycle (S4). Here, the respiratory cycle is set to a range of t11 to t12. t1 is the lower limit of the respiratory cycle, and t2 is the upper limit of the respiratory cycle. In this embodiment, the respiratory cycle range is set to, for example, a range of 3 seconds to 5 seconds. The respiratory cycle range is pre-set in the memory unit 30, but the setting of the respiratory cycle range can be changed as appropriate.

[0068] The detection unit 22 determines that a person is present in the detection target space SP1 if the period T of the periodic time change of the time difference is the same as the respiratory cycle (t11≦T≦t12) (S4:YES), 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).

[0069] Furthermore, in the periodic change detection process of step S3, even if the detected object does not undergo a periodic change, 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. As a result, the lighting process of step S5 is executed, and the lighting load, which is load 3, is turned on.

[0070] On the other hand, if the period T of the periodic change in the time difference in the comparison process in step S4 is different from the respiratory cycle (S4: No), it is determined that no person is present in the detection target space SP1, and an absence detection signal is output to the load control unit 23. When the load control unit 23 receives an absence detection signal from the detection unit 22, it outputs an off control signal to the drive circuit 40.

[0071] Then, the detection unit 22 excludes an object from detection if the period T of the periodic time change of the time difference is different from the respiration cycle (S6). More specifically, the detection unit 22 stores the region (one or more moving points) where the excluded object exists as an excluded region in the storage unit 30, and excludes the excluded region from detection from the next time onward.

[0072] When the drive circuit 40 receives an off control signal from the load control unit 23, it controls the switch element 41 to a non-conductive state, interrupting the power supply to the lighting load, which is load 3, and turning off the lighting load (S7).

[0073] (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 are 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 is acquired from the radio wave sensor 10. 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 moving object is detected based on the output signal output from the radio wave sensor 10. In the detection process, a time difference is calculated, which is the difference between two output signals output by the radio wave sensor 10 during two different detection periods, and the presence or absence of a moving object is detected based on a comparison result obtained by comparing the calculated time difference with a threshold Th1. In the detection process, if the temporal change of the detected object is a periodic change and differs from the periodic change associated with human respiration, the object is excluded from detection. One embodiment of the (computer) program is a program that causes one or more processors to execute the above motion detection method.

[0074] The following lists some modifications of the above embodiment. The modifications described below can be combined and applied as appropriate.

[0075] 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.

[0076] 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.

[0077] In the above embodiment, where "greater than or equal to" is used in the comparison of the magnitude relationship between 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 or equal to" is used, it may also be used as "less than" or "smaller than."

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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).

[0084] (summary) Based on the embodiments described above, the following aspects are disclosed.

[0085] 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 transmission wave, which is a frequency-modulated radio wave, to the detection target space, and 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. The detection unit (22) detects moving objects based on the output signal output from the radio wave sensor (10). The detection unit (22) calculates a time difference, which is the difference between the intensity of two output signals output by the radio wave sensor (10) during two different detection periods, and detects the presence or absence of a moving object based on the comparison result obtained by comparing the time difference with a threshold (Th1). The detection unit (22) excludes an object from detection if the temporal change of the detected object is a periodic change and is different from the periodic change associated with human respiration.

[0086] According to this embodiment, the detection unit (22) can detect a moving object, and if the temporal change of the detected object is a periodic change and is different from the periodic change associated with human respiration, it can determine that it is a mechanical disturbance and exclude that object from detection. This makes it possible to reduce false detections of mechanical disturbances.

[0087] 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 motion points among the plurality of reflection points whose time difference is greater than or equal to a threshold (Th1).

[0088] According to this embodiment, the detection unit (22) becomes capable of detecting a moving body corresponding to the distribution of one or more moving points.

[0089] In the third embodiment of the motion detection system (1), in the second embodiment, the detection unit (22) detects whether the temporal change in the distribution of one or more moving points is a repeating periodic change. The detection unit (22) excludes the distribution of one or more moving points from detection if the period (T) of the detected periodic change is different from the respiratory cycle (t11≦T≦t12).

[0090] According to this embodiment, the detection unit (22) can determine that a temporal change in the distribution of one or more moving points is a repetitive periodic change, and that the periodic change differs from the respiratory cycle, and can exclude the distribution of one or more moving points from detection.

[0091] In the fourth embodiment of the motion detection system (1), in any one of the first to third embodiments, the detection unit (22) stores the region in which an object excluded from detection exists as an excluded region, and excludes the excluded region from detection from the next time onward.

[0092] According to this embodiment, false detections in areas where an object that has been initially determined to be a mechanical disturbance exists can be reduced. In addition, the processing load on the detection unit (22) can be reduced.

[0093] The fifth embodiment of the motion detection system (1) further comprises a housing (2) in any one of the first to fourth embodiments. The housing (2) houses a radio wave sensor (10) and is positioned on a wall next to the space to be detected (SP1) or on the ceiling above the space to be detected (SP1).

[0094] 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).

[0095] In the sixth embodiment of the motion detection system (1), in the fifth embodiment, the housing (2) further houses the detection unit (22).

[0096] 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.

[0097] The wiring device (100) of the seventh embodiment comprises a motion detection system (1) according to any one of the first to sixth embodiments, a load connection section (50), and a load control section (23). A load 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).

[0098] This embodiment makes it possible to reduce false detections of mechanical disturbances.

[0099] The eighth embodiment of the load system (200) comprises a motion detection system (1) according to any one of the first to sixth 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.

[0100] This embodiment makes it possible to reduce false detections of mechanical disturbances.

[0101] The ninth aspect of the motion detection method includes an acquisition process and a detection process. In the acquisition process, an output signal is acquired from a radio wave sensor (10). The radio wave sensor (10) transmits a transmission wave, which is a frequency-modulated radio wave, into the detection target space (SP1). 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 moving object is detected based on the output signal output from the radio wave sensor (10). In the detection process, a time difference is calculated, which is the difference between the intensity of two output signals output by the radio wave sensor during two different detection periods. Based on the comparison result obtained by comparing the time difference with a threshold (Th1), the presence or absence of a moving object is detected. In the detection process, if the temporal change of the detected object is a periodic change and is different from the periodic change associated with human respiration, the object is excluded from the detection target.

[0102] This embodiment makes it possible to reduce false detections of mechanical disturbances.

[0103] The tenth embodiment of the program is a program for causing one or more processors to execute the motion detection method of the ninth embodiment.

[0104] This embodiment makes it possible to reduce false detections of mechanical disturbances.

[0105] 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 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, etc., which are executed by the motion detection system (1).

[0106] The configurations relating to the second to sixth aspects are not essential to the motion detection system (1) and can be omitted as appropriate. [Explanation of symbols]

[0107] 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 301 desk 302 Electric fan 401 Ceiling 402 Wall SP1 Detection Target Space Th1 threshold t11,t12 breathing cycle t13 mechanical cycle

Claims

1. A radio wave sensor transmits a frequency-modulated radio wave, which is a transmission wave, to a 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. The system includes a detection unit that detects the moving object based on the output signal output from the radio wave sensor, The detection unit is The time difference, which is the difference between the two output signal intensities output by the radio wave sensor during two different detection periods, is calculated. Based on the comparison result obtained by comparing the above time difference with the threshold value, the presence or absence of the moving object is detected. If the temporal change of the moving object is a periodic change and differs from the periodic change associated with human respiration, the object is excluded from detection. Motion detection system.

2. The radio wave sensor outputs an output signal based on the reflected waves reflected at each of the multiple reflection points on the surface of the object and the transmitted wave. The detection unit is Obtain the distribution of one or more moving points among multiple reflection points whose time difference is greater than or equal to the threshold. The motion detection system according to claim 1.

3. The detection unit is The system detects whether the temporal change in the distribution of the one or more moving points is a repeating periodic change, and if the period of the detected periodic change is different from the respiratory cycle, it excludes the distribution of the one or more moving points from the detection target. The motion detection system according to claim 2.

4. The detection unit is The region in which the object excluded from detection exists is stored as an excluded region. From the next time onward, the aforementioned excluded area will be excluded from detection. The conductor detection system according to claim 1.

5. 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.

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

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

8. A motion detection system according to any one of claims 1 to 6, Load and A load control unit controls the operating state of the load based on the object detection result by the motion detection system, Equipped with, Load system.

9. The process involves transmitting a frequency-modulated radio wave, which is a transmitted wave, into a detection target space, and when an object in the detection target space reflects the transmitted wave, receiving a reflected wave, and then acquiring the output signal from a radio wave sensor that outputs an output signal based on the transmitted wave and the reflected wave. The process includes detecting the moving object based on the output signal output from the radio wave sensor, In the aforementioned detection process, The time difference, which is the difference between the two output signal intensities output by the radio wave sensor during two different detection periods, is calculated. Based on the comparison result obtained by comparing the above time difference with the threshold value, the presence or absence of the moving object is detected. If the temporal change of the moving object is a periodic change and differs from the periodic change associated with human respiration, the object is excluded from detection. Motion detection method.

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

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