JP6920645B2 - Human detection system - Google Patents

Description

The present invention relates to a human detection system.

Conventionally, a human detection system (infrared detection device) that detects infrared energy radiated from a human body and detects the presence or movement of the human body has been provided (see, for example, Patent Document 1).

In the system described in Patent Document 1, the output of the I / V conversion circuit that converts the current signal from the pyroelectric element into voltage conversion is amplified by the voltage amplification circuit, and the output of the voltage amplification circuit sets the first detection level. When it exceeds, a human body detection signal is output. This system is provided with a mode switching determination unit that switches between a detection mode in which the current flowing through at least a part of the circuits is the rated current and a standby mode in which the current is smaller than the rated current. The mode switching determination unit sets the standby mode when the output of the voltage amplification circuit is lower than the first detection level and is equal to or lower than the second detection level, and detects when the output of the voltage amplification circuit exceeds the second detection level. Select a mode.

Japanese Unexamined Patent Publication No. 2006-58119

In the conventional human detection system as described above, in the standby mode, the output of the voltage amplifier circuit is equal to or lower than the second detection level lower than the first detection level for determining whether or not a person is present. No determination is made as to whether or not a person exists. That is, in the conventional human detection system, it is determined whether or not a person exists only in the detection mode, and the sensitivity to the person is substantially constant. Therefore, in the conventional human detection system, for example, if the sensitivity is set according to a large movement of a person (walking, etc.), the detection omission of a person's fine movement (movement, etc.) is likely to occur, and the sensitivity is adjusted to the fine movement of a person. If is set, erroneous detection due to the influence of noise or the like is likely to occur.

The present invention aims at providing have been made in view of the above circumstances, hardly occurs detect leakage of the fine movement of a person, and the erroneous human test Chishi stem capable of suppressing the occurrence of detection.

The human detection system according to one aspect of the present invention includes a light receiving unit and a determination unit. The light receiving unit has a light receiving element that outputs a signal corresponding to a change in the light receiving intensity of infrared rays from the detection space. Based on the output signal of the light receiving unit, the determination unit determines whether the state of the detection space is an existence state in which a person exists in the detection space or an absence state in which no person exists in the detection space. To judge. The operation mode of the determination unit includes an approach detection mode for detecting the presence / absence of a person entering the detection space and a stay detection mode for detecting the presence / absence of a person leaving the detection space. In the approach detection mode, the determination unit detects the presence or absence of a person entering the detection space based on the output signal of the light receiving unit based on whether or not the first determination condition is satisfied, and detects the stay. In the mode, the presence or absence of a person leaving the detection space is detected based on whether or not the second determination condition is satisfied based on the output signal of the light receiving unit. The first determination condition and the second determination condition are different from each other. As the second determination condition in the stay detection mode, a determination condition relating to the time integral value of the output signal of the light receiving unit during the human breathing cycle or longer is used. For example, in the approach detection mode, the determination unit determines that the existence state is satisfied if the comparison result between the amplitude of the output signal of the light receiving unit and the first threshold value satisfies the first determination condition. In the stay detection mode, the determination unit is a value obtained from the output signal of the light receiving unit, and the comparison result between the evaluation value according to the movement of a person in the detection space and the second threshold value is the second determination. It is configured to determine the absence state if the condition is satisfied.

The present invention has an advantage that the omission of detection of a person's fine movement is unlikely to occur and the occurrence of false detection can be suppressed.

FIG. 1 is a block diagram showing a configuration of a human detection system according to the first embodiment of the present invention. FIG. 2 is a perspective view showing an example of using the human detection system of the above. FIG. 3 is a waveform diagram of an output signal of the first light receiving unit in the human detection system of the above. FIG. 4A is a waveform diagram of the output signals of the first light receiving unit and the second light receiving unit in the human detection system of the above. FIG. 4B is a waveform diagram of evaluation values in the same human detection system. FIG. 5 is an explanatory diagram conceptually showing the operation of the determination unit of the above-mentioned human detection system. FIG. 6 is a timing chart showing an operation example of the above-mentioned human detection system. FIG. 7 is an explanatory diagram conceptually showing the operation of the determination unit of the human detection system according to the first modification of the first embodiment of the present invention. FIG. 8 is an explanatory diagram conceptually showing the operation of the determination unit of the human detection system according to the second modification of the first embodiment of the present invention.

Each of the following embodiments relates to a human detection system, and more particularly to a human detection system that detects the presence or absence of a person in the detection space based on the intensity of infrared rays received from the detection space. However, the human detection system according to each embodiment described below is only an example of the present invention, and the present invention is not limited to the following human detection systems. Therefore, other than the following embodiments, various changes can be made according to the design and the like as long as the technical idea of the present invention is not deviated.

(Embodiment 1)
The person detection system 10 according to the present embodiment will be described with reference to FIG.

The person detection system 10 detects the presence or absence of a person 91 in a detection space 90 set in, for example, a living room of a house. The human detection system 10 detects the presence or absence of the human 91 based on the change in the light receiving intensity of infrared rays from the detection space 90. That is, in the human detection system 10, the presence of the person 91 is caused by a change in the light receiving intensity of infrared rays caused by the movement of the person 91 from the outside of the detection space 90 into the detection space 90 or the slight movement of the person 91 in the detection space 90. Detects the presence or absence of. The term "fine movement" as used herein means a relatively small movement of the person 91, such as a fluctuation of the body due to the breathing movement of the person 91 and a movement of the person.

The human detection system 10 detects whether the state of the detection space 90 is an existing state or an absent state. The "existence state" referred to here is a state in which a person 91 exists in the detection space 90. The "absent state" is a state in which the person 91 does not exist in the detection space 90. Therefore, when the person 91 does not exist in the detection space 90, the detection result of the person detection system 10 is "absent state". When the person 91 enters the detection space 90, the detection result of the person detection system 10 changes from the "absent state" to the "existing state". After that, while the person 91 is staying in the detection space 90, the detection result of the person detection system 10 maintains the "existence state". When the person 91 leaves the detection space 90, the detection result of the person detection system 10 changes from the "existence state" to the "absence state".

In this embodiment, as an example, the detection result of the human detection system 10 is output to the lighting control system 80 (see FIG. 1). The lighting control system 80 includes a lighting fixture 81 (see FIG. 1) that illuminates the detection space 90, and a control device 82 (see FIG. 1) that controls the lighting fixture 81. The detection result of the human detection system 10 is input to the control device 82. If the detection result of the human detection system 10 is "existence state", the control device 82 turns on the lighting fixture 81. On the other hand, if the detection result of the human detection system 10 is "absent state", the control device 82 turns off the lighting fixture 81. The control device 82 may be a switch inserted into the power supply path to the luminaire 81 to turn on / off the energization of the luminaire 81. As described above, the person detection system 10 of the present embodiment is used in the lighting control system 80 that automatically controls the lighting fixture 81 according to the presence or absence of the person 91. As a result, the person detection system 10 can automatically turn on the lighting fixture 81 when the person 91 enters the detection space 90. Further, the person detection system 10 automatically turns off the lighting fixture 81 when the person 91 leaves the detection space 90, so that wasteful power consumption due to forgetting to turn off the lighting fixture 81 can be suppressed.

(1) Configuration The human detection system 10 includes a sensor main body 1 and a detection circuit 2 as shown in FIG.

The sensor body 1 has a first light receiving element 111 and a second light receiving element 112. Hereinafter, when the first light receiving element 111 and the second light receiving element 112 are not particularly distinguished, each of the first light receiving element 111 and the second light receiving element 112 is referred to as a "light receiving element 11". The light receiving element 11 is a pyroelectric element and outputs a signal (electric signal) corresponding to a change in the light receiving intensity of infrared rays from the detection space 90.

The sensor main body 1 has a first conversion circuit 121, a first amplifier circuit 131, and a first A / D converter 141 as a circuit for processing an electric signal output from the first light receiving element 111. Further, the sensor main body 1 has a second conversion circuit 122, a second amplifier circuit 132, and a second A / D converter 142 as circuits for processing the electric signal output from the second light receiving element 112. .. The sensor body 1 outputs the outputs (electrical signals) of the first A / D converter 141 and the second A / D converter 142 to the detection circuit 2.

The first conversion circuit 121 converts the electric signal output from the first light receiving element 111 from a current signal to a voltage signal. The first amplifier circuit 131 amplifies the voltage signal output from the first conversion circuit 121. The first A / D converter 141 converts an analog signal (voltage signal) output from the first amplifier circuit 131 into a digital signal. The second conversion circuit 122, the second amplifier circuit 132, and the second A / D converter 142 have the same configurations as the first conversion circuit 121, the first amplifier circuit 131, and the first A / D converter 141, and have the same configuration as the second conversion circuit 121. The signal processing of the electric signal output from the light receiving element 112 is performed.

The sensor body 1 is used in combination with the optical system 15 (see FIG. 2). The optical system 15 is composed of a lens, a mirror, or a combination thereof, and collects infrared rays from the detection space 90 on the light receiving element 11. The sensor body 1 is housed in one housing together with the detection circuit 2. As shown in FIG. 2, the person detection system 10 including the sensor body 1 is installed on the ceiling of a living room of a house, for example, and receives infrared rays from a detection space 90 set in the living room.

The detection circuit 2 includes a determination unit 4, a multiplication unit 5, an integration unit 6, an output unit 7, an integration timer 41, a standby timer 42, and a delay timer 43. Further, the detection circuit 2 has a first buffer 211 and a first filter unit 221 as a part for performing signal processing of an input signal (digital signal) from the first A / D converter 141. Further, the detection circuit 2 has a second buffer 212 and a second filter unit 222 as a part for performing signal processing of an input signal (digital signal) from the second A / D converter 142.

The input signal from the first A / D converter 141 is input to the first filter unit 221 via the first buffer 211. The first filter unit 221 attenuates or amplifies a specific frequency component. The input signal from the second A / D converter 142 is input to the second filter unit 222 via the second buffer 212. The second filter unit 222 attenuates or amplifies a specific frequency component.

In the present embodiment, the detection circuit 2 mainly includes a computer such as a microcomputer. The detection circuit 2 realizes the functions of the above-mentioned parts by executing the program recorded in the memory of the microcomputer by the processor of the microcomputer. The program may be pre-recorded in a memory, provided through a telecommunication line such as the Internet, or may be recorded and provided on a recording medium such as a memory card.

The output of the first light receiving element 111 is input to the multiplication unit 5 via the first conversion circuit 121, the first amplifier circuit 131, the first A / D converter 141, the first buffer 211, and the first filter unit 221. .. The output of the second light receiving element 112 is input to the multiplication unit 5 via the second conversion circuit 122, the second amplifier circuit 132, the second A / D converter 142, the second buffer 212, and the second filter unit 222. .. The first light receiving element 111 constitutes the first light receiving unit 31 together with the first conversion circuit 121, the first amplifier circuit 131, the first A / D converter 141, the first buffer 211, and the first filter unit 221. The second light receiving element 112 constitutes the second light receiving unit 32 together with the second conversion circuit 122, the second amplifier circuit 132, the second A / D converter 142, the second buffer 212, and the second filter unit 222. The first light receiving unit 31 constitutes the light receiving unit 3 together with the second light receiving unit 32.

That is, the light receiving unit 3 (the first light receiving unit 31 and the second light receiving unit 32) has a light receiving element 11 and multiplies the output signals V1 and V2 according to the change in the light receiving intensity of infrared rays from the detection space 90. Output to 5. The output signal V1 of the first light receiving unit 31 and the output signal V2 of the second light receiving unit 32 are separately input to the multiplication unit 5. Further, of the output signals V1 and V2 of the light receiving unit 3, the output signal V1 of the first light receiving unit 31 is directly output to the determination unit 4. Therefore, the output signals V1 and V2 of the first light receiving unit 31 and the second light receiving unit 32 are input to the determination unit 4 via the multiplication unit 5 and the integrating unit 6, and the output signal V1 of the first light receiving unit 31 is input to the determination unit 4. It is input without going through the multiplication unit 5 and the integration unit 6.

The first filter unit 221 extracts an AC component from the output of the first light receiving element 111. The second filter unit 222 extracts an AC component from the output of the second light receiving element 112. The frequency band passed by each of the first filter unit 221 and the second filter unit 222 is set to, for example, 0.3 Hz to 1 Hz. This frequency band is a frequency band corresponding to the fine movement of the person 91. Low frequency components (including DC components) have been removed from the outputs of the first filter unit 221 and the second filter unit 222, that is, the output signal V1 of the first light receiving unit 31 and the output signal V2 of the second light receiving unit 32, respectively. It becomes an AC signal.

Here, the frequency band (passing band) to be passed by the first filter 221 is different between the output signal V1 directly output to the determination unit 4 and the output signal V1 output to the multiplication unit 5. Is preferable. In this case, for the output signal V1 output from the first light receiving unit 31 to the multiplication unit 5, the pass band of the first filter 221 is, for example, 0.3 Hz to 1 Hz as described above. On the other hand, with respect to the output signal V1 directly output from the first light receiving unit 31 to the determination unit 4, the pass band of the first filter 221 is, for example, a frequency band having a center frequency of around 1 Hz. The first filter 221 may have an individual filter for each output destination, or may switch the pass band according to the operation mode of the determination unit 4 described later.

The multiplication unit 5 multiplies the output signal V1 of the first light receiving unit 31 and the output signal V2 of the second light receiving unit 32. The multiplication unit 5 multiplies the instantaneous value of the output signal V1 of the first light receiving unit 31 with the instantaneous value of the output signal V2 of the second light receiving unit 32. The multiplication unit 5 multiplies the output signal V1 of the first light receiving unit 31 and the output signal V2 of the second light receiving unit 32 to multiply the output signal V1 of the first light receiving unit 31 and the output signal of the second light receiving unit 32. Synchronous detection is performed to extract components in phase with V2.

The integrating unit 6 integrates the multiplication result of the multiplication unit 5. The integrating unit 6 has a memory for temporarily storing the multiplication result of the multiplication unit 5, and integrates the multiplication result of the multiplication unit 5 stored in this memory. The integrating unit 6 obtains the integrated value of the multiplication result for the latest integration time. In other words, the integration unit 6 obtains the value obtained by integrating the multiplication results as the evaluation value Vi1 for the period for the integration time (integration target period) with the present as the end point. That is, the integrating unit 6 executes so-called moving integration. The multiplication result for the latest integration time is accumulated in the memory of the integration unit 6, and the multiplication result accumulated in the memory is updated by discarding the oldest data in order. The integrating unit 6 calculates the integrated value (evaluation value Vi1) of the multiplication result for the latest integration time by integrating the multiplication result for the integration time stored in the memory. The length of the integration time is appropriately selected from, for example, 30 seconds, 60 seconds, 90 seconds, and the like, depending on the application of the human detection system 10. As an example, the integration time is 30 seconds.

Based on the output signal of the light receiving unit 3, the determination unit 4 states that the state of the detection space 90 is "existence state" in which the person 91 exists in the detection space 90 and "absence state" in which the person 91 does not exist in the detection space 90. Which of the above is determined.

The operation mode of the determination unit 4 includes an approach detection mode and a stay detection mode. The approach detection mode is an operation mode for detecting the presence or absence of the person 91 entering the detection space 90. The stay detection mode is an operation mode for detecting the presence / absence of the exit of the person 91 from the detection space 90.

In the approach detection mode, the determination unit 4 determines that the existence state is satisfied if the comparison result between the amplitude of the output signal V1 and the first threshold value Vth1 (see FIG. 3) satisfies the first determination condition. Here, the output signal V1 is the output signal V1 of the first light receiving unit 31 that is directly input to the determination unit 4. As an example in the present embodiment, the first determination condition is that the amplitude of the output signal V1 is equal to or greater than the first threshold value Vth1.

For example, when the intensity of infrared rays received from the detection space 90 in the light receiving unit 3 changes due to the entry of a person 91 into the detection space 90 or the like, as shown in FIG. 3, a relatively large fluctuation occurs in the output signal V1. The amplitude of the output signal V1 is synonymous with the amount of change (absolute value) from the reference voltage V0 in the output signal V1. In the example of FIG. 3, the amplitude of the output signal V1 reaches the first threshold value Vth1 at time t10. Therefore, the determination unit 4 determines that the comparison result between the amplitude of the output signal V1 and the first threshold value Vth1 satisfies the first determination condition at the time t10, and determines that the existence state is satisfied.

In the stay detection mode, the determination unit 4 compares the evaluation value Vi1 which is a value obtained from the output signals V1 and V2 and corresponds to the movement of the person 91 in the detection space 90 with the second threshold value Vth2 (see FIG. 4B). If the result satisfies the second determination condition, it is determined to be absent. Here, the evaluation value Vi1 is the output value of the integrating unit 6. That is, the evaluation value Vi1 is a value obtained by multiplying the output signal V1 of the first light receiving unit 31 and the output signal V2 of the second light receiving unit 32 by the multiplication unit 5 and integrating the multiplication result by the integration unit 6, and is an output. It is an integrated value of signals V1 and V2.

In the present embodiment, as an example, the second determination condition is a state in which the evaluation value Vi1 is less than the second threshold value Vth2 from the time when the evaluation value Vi1 becomes less than the second threshold value Vth2 until a predetermined delay time elapses. Is to continue. Specifically, the determination unit 4 compares the evaluation value Vi1 with the second threshold value Vth2, and sets a temporary flag while the evaluation value Vi1 is less than the second threshold value Vth2. Then, when the delay time elapses while the temporary flag is set, the determination unit 4 determines that the second determination condition is satisfied, and determines that the state is absent. As a result, the determination unit 4 does not immediately determine the absence state even if the evaluation value Vi1 becomes less than the second threshold value Vth2, and delays the determination of the absence state by the delay time, so that the so-called off-delay function To realize.

For example, even when the person 91 is stationary, the person 91 causes a movement (fine movement) of about several mm due to a breathing motion or the like. Therefore, when the person 91 is present in the detection space 90, the output signals V1 and V2 of the first light receiving unit 31 and the second light receiving unit 32 correspond to the magnitude of the movement of the person 91, for example, as shown in FIG. 4A. It has included the detection Ingredients of phase. The output signals V1 and V2 illustrated in FIG. 4A are all less than the first threshold value Vth1. Since the first light receiving unit 31 and the second light receiving unit 32 receive infrared rays from the same location, they are included in each of the output signal V1 of the first light receiving unit 31 and the output signal V2 of the second light receiving unit 32. The detection components are correlated with each other. Therefore, in the multiplication result of the output signal V1 of the first light receiving unit 31 and the output signal V2 of the second light receiving unit 32, the in-phase detection component is emphasized. Further, in the moving integral value of the multiplication result of the multiplication unit 5, a randomly generated noise component is reduced. Therefore, as shown in FIG. 4B, the evaluation value Vi1 consisting of the mobile integral value of the multiplication result of the multiplication unit 5 increases from the start time of the integration to the time t20 when the integration time elapses, and becomes substantially constant after the time t20. Become. In the example of FIG. 4B, since the evaluation value Vi1 is equal to or higher than the second threshold value Vth2 at the time t20, the determination unit 4 has a second comparison result between the evaluation value Vi1 and the second threshold value Vth2 at the time t20. It is judged that the judgment condition of is not satisfied.

Further, in the present embodiment, the operation mode of the determination unit 4 includes a standby mode in addition to the approach detection mode and the stay detection mode. That is, the determination unit 4 has at least three operation modes (entry detection mode, stay detection mode, and standby mode). Details of each operation mode will be described in the column of "(2) Operation".

The determination unit 4 operates by selectively selecting an operation mode from a plurality of operation modes including an approach detection mode, a stay detection mode, and a stay detection mode. Therefore, for example, both the approach detection mode and the stay detection mode are not selected at the same time.

When the determination unit 4 determines in the stay detection mode that it is in the absence state, the determination unit 4 switches the operation mode from the stay detection mode to the approach detection mode. Further, when the determination unit 4 determines that the existence state is present in the approach detection mode, the determination unit 4 switches the operation mode from the approach detection mode to the standby mode. Further, if the amplitude of the output signal V1 is less than the first threshold value Vth1 when a predetermined standby time elapses from the time when the operation in the standby mode is started, the determination unit 4 stays in the operation mode from the standby mode. Switch to detection mode. Further, when the amplitude of the output signal V1 becomes equal to or higher than the third threshold value in the stay detection mode, the determination unit 4 switches the operation mode from the stay detection mode to the standby mode. In this embodiment, it is assumed that the third threshold value is the same value as the first threshold value Vth1. However, the third threshold value may be a value different from the first threshold value Vth1.

As a result, in the state where the person 91 does not exist in the detection space 90, the determination unit 4 basically operates in the approach detection mode and detects the presence or absence of the person 91 entering the detection space 90. On the other hand, in the state where the person 91 exists in the detection space 90, the determination unit 4 basically operates in the stay detection mode and detects whether or not the person 91 has left the detection space 90.

The integration timer 41 counts the integration time. The integration timer 41 starts counting the integration time when the integration unit 6 starts the integration process. The count value of the integration timer 41 is reset when the determination unit 4 starts or ends the operation in the stay detection mode.

The standby timer 42 counts the standby time. When the determination unit 4 starts the operation in the standby mode, the standby timer 42 starts counting the standby time. The count value of the standby timer 42 is reset when the standby timer 42 finishes counting the standby time. The length of the standby time is appropriately set in the range of, for example, several seconds to 10 seconds, depending on the application of the human detection system 10. As an example, the waiting time is 10 seconds.

The delay timer 43 counts the delay time. When the determination unit 4 determines that the evaluation value Vi1 is less than the second threshold value Vth2 in the stay detection mode, the delay timer 43 starts counting the delay time. The count value of the delay timer 43 is reset when the determination unit 4 starts or ends the operation in the stay detection mode. The length of the delay time is appropriately selected from, for example, 30 seconds, 60 seconds, 90 seconds, and the like, depending on the application of the human detection system 10. As an example, the delay time is 30 seconds. It is preferable that the length of the delay time is variable and can be arbitrarily changed by the user. The delay time is preferably longer than the standby time.

By the way, the multiplication unit 5 and the integration unit 6 are stopped while the operation mode of the determination unit 4 is in the approach detection mode and the operation mode of the determination unit 4 is in the standby mode. That is, the multiplication unit 5 and the integration unit 6 operate only while the operation mode of the determination unit 4 is in the stay detection mode. Therefore, the integration timer 41 linked to the integration unit 6 starts counting the integration time with the trigger of the determination unit 4 starting the operation in the stay detection mode. Further, the determination unit 4 does not compare the evaluation value Vi1 with the second threshold value Vth2 until the integration timer 41 finishes counting the integration time. When the integration timer 41 finishes counting the integration time, the comparison between the evaluation value Vi1 and the second threshold value Vth2 is started. That is, even if the determination unit 4 is operating in the stay detection mode, the evaluation value Vi1 and the second threshold value Vth2 are compared from the time when the integration unit 6 starts the integration process until the integration time elapses. Not performed. Therefore, the determination unit 4 sets the evaluation values Vi1 and the second evaluation value Vi1 while the operation mode is the approach detection mode or the standby mode, and even in the stay detection mode until the integration timer 41 finishes counting the integration time. No comparison is made with the threshold value Vth2.

On the other hand, the determination unit 4 performs the comparison between the amplitude of the output signal V1 and the first threshold value Vth1 at any time regardless of the operation mode. Therefore, the determination unit 4 can compare the amplitude of the output signal V1 with the first threshold value Vth1 (third threshold value) even in the stay detection mode, and the amplitude of the output signal V1 is the first threshold value Vth1. When the above is reached, the operation mode is switched from the stay detection mode to the standby mode.

The output unit 7 outputs the determination result of the determination unit 4 to the lighting control system 80 as the detection result of the human detection system 10. The output unit 7 serially outputs a determination signal representing the determination result of the determination unit 4 to the human detection system 10. Specifically, the output unit 7 outputs a determination signal including a start bit, a determination result, and a stop bit. The determination signal may include, for example, mode information indicating the operation mode of the determination unit 4 and information such as waveforms of the output signals V1 and V2, in addition to the determination result of "existence state" or "absence state". ..

( 2 ) Operation Next, the operation of the person detection system 10 according to the present embodiment will be described with reference to FIG.

FIG. 5 is an explanatory diagram conceptually showing the operation of the determination unit 4. In FIG. 5, the first circle C1 represents the determination result of the determination unit 4 as “absent state”. The second circle C2 represents the determination result of the determination unit 4 as "existence state". Further, in FIG. 5, the broken line arrow represents the processing flow of the determination unit 4 based on the comparison result between the amplitude of the output signal V1 and the first threshold value Vth1. The solid arrow indicates the processing flow of the determination unit 4 based on the comparison result between the evaluation value Vi1 and the second threshold value Vth2.

When the power is turned on to the human detection system 10 and the human detection system 10 is activated, the determination unit 4 first operates in the approach detection mode (step S1). At this time, since the determination result of the determination unit 4 is in the absence state, step S1 (entry detection mode) is in the first circle C1.

In the approach detection mode of step S1, the determination unit 4 compares the amplitude of the output signal V1 with the first threshold value Vth1. At this time, if the amplitude of the output signal V1 is less than the first threshold value Vth1, the determination unit 4 continues the operation in the approach detection mode (step S2). On the other hand, when the amplitude of the output signal V1 becomes equal to or higher than the first threshold value Vth1, the determination unit 4 switches the operation mode from the approach detection mode to the standby mode (step S3). At this time, since the determination result of the determination unit 4 is in the existing state, step S4 (standby mode) is in the second circle C2.

In the standby mode of step S4, the determination unit 4 compares the amplitude of the output signal V1 with the first threshold value Vth1 when the standby timer 42 finishes counting the standby time. If the amplitude of the output signal V1 is less than the first threshold value Vth1 when the standby timer 42 finishes counting the standby time, the determination unit 4 resets the count value of the standby timer 42 and sets the operation mode to the standby mode. To switch to the stay detection mode (step S5). At this time, since the determination result of the determination unit 4 is in the existing state, step S6 (stay detection mode) is in the second circle C2. On the other hand, if the amplitude of the output signal V1 is equal to or greater than the first threshold value Vth1 when the standby timer 42 finishes counting the standby time, the determination unit 4 resets the count value of the standby timer 42 and sets the standby mode. Continues the operation of (step S7).

In the stay detection mode of step S6, the determination unit 4 starts comparing the evaluation value Vi1 with the second threshold value Vth2 at any time from the time when the integration timer 41 finishes counting the integration time. Then, when the evaluation value Vi1 becomes equal to or higher than the second threshold value Vth2, the determination unit 4 continues the operation in the stay detection mode without resetting the count value of the integration timer 41 (step S9). Further, the determination unit 4 also compares the amplitude of the output signal V1 with the first threshold value Vth1 in the stay detection mode, and if the amplitude of the output signal V1 becomes equal to or higher than the first threshold value Vth1, the operation mode is set. The stay detection mode is switched to the standby mode (step S10). At this time, the determination unit 4 resets the count value of the integration timer 41.

Further, in the stay detection mode of step S6, when the evaluation value Vi1 becomes less than the second threshold value Vth2, the delay timer 43 starts counting the delay time. The determination unit 4 continues the operation in the stay detection mode until the delay timer 43 finishes counting the delay time. If the evaluation value Vi1 is less than the second threshold value Vth2 when the delay timer 43 finishes counting the delay time, the determination unit 4 switches the operation mode from the stay detection mode to the approach detection mode (step S8). At this time, since the determination result of the determination unit 4 is in the absence state, step S1 (entry detection mode) is in the first circle C1. At this time, the determination unit 4 resets the count value of the integration timer 41 and the count value of the delay timer 43.

On the other hand, when the evaluation value Vi1 becomes equal to or higher than the second threshold value Vth2 while the delay timer 43 is counting the delay time, the determination unit 4 continues the operation in the stay detection mode (step S9). At this time, the determination unit 4 resets the count value of the integration timer 41 and the count value of the delay timer 43. Further, when the amplitude of the output signal V1 becomes equal to or higher than the first threshold value Vth1 while the delay timer 43 is counting the delay time, the determination unit 4 switches the operation mode from the stay detection mode to the standby mode (step S10). At this time, the determination unit 4 resets the count value of the integration timer 41 and the count value of the delay timer 43.

By the above-described operation, in the approach detection mode, the determination unit 4 determines the existence state when the amplitude of the output signal V1 becomes equal to or higher than the first threshold value Vth1. Then, when the determination unit 4 determines that the existence state is determined in the approach detection mode, the determination unit 4 switches the operation mode from the approach detection mode to the standby mode. Further, if the amplitude of the output signal V1 is less than the first threshold value Vth1 when the standby time elapses from the time when the operation in the standby mode is started, the determination unit 4 changes the operation mode from the standby mode to the stay detection mode. Switch. Further, in the stay detection mode, the determination unit 4 is in a state where the evaluation value Vi1 is less than the second threshold value Vth2 from the time when the evaluation value Vi1 becomes less than the second threshold value Vth2 until a predetermined delay time elapses. If it continues, it is determined to be absent. Then, when the determination unit 4 determines that the absence state is determined in the stay detection mode, the determination unit 4 switches the operation mode from the stay detection mode to the approach detection mode.

Table 1 summarizes the operations of the determination unit 4 described above.

That is, if the operation mode of the determination unit 4 is the approach detection mode, the determination target by the determination unit 4 is the amplitude of the output signal V1. Then, the determination unit 4 performs the processing of step S2 or step S3 according to the comparison result between the amplitude of the output signal V1 and the first threshold value Vth1. The determination result of the determination unit 4 is absent while the operation mode of the determination unit 4 is the approach detection mode.

If the operation mode of the determination unit 4 is the standby mode, the determination target of the determination unit 4 is the amplitude of the output signal V1. Then, the determination unit 4 performs the processing of step S5 or step S7 according to the comparison result between the amplitude of the output signal V1 and the first threshold value Vth1. While the operation mode of the determination unit 4 is the standby mode, the determination result of the determination unit 4 is in the existing state.

If the operation mode of the determination unit 4 is the stay detection mode, the determination target of the determination unit 4 is both the amplitude of the output signal V1 and the evaluation value Vi1. Then, the determination unit 4 performs the process of step S10 according to the comparison result between the amplitude of the output signal V1 and the first threshold value Vth1. The determination unit 4 performs the process of step S8 or S9 according to the comparison result between the evaluation value Vi1 and the second threshold value Vth2. While the operation mode of the determination unit 4 is the stay mode, the determination result of the determination unit 4 is in the existing state.

By the way, the processing of the determination unit 4 has a priority, and the determination unit 4 preferentially executes the processing having a high priority. For example, in the stay detection mode, the determination unit 4 targets both the amplitude of the output signal V1 and the evaluation value Vi1, but the processing according to the amplitude of the output signal V1 is more than the processing according to the evaluation value Vi1. Has a higher priority. That is, when the determination unit 4 is operating in the stay detection mode, the amplitude of the output signal V1 becomes the first threshold value Vth1 or more, and the evaluation value Vi1 becomes the second threshold value Vth2 or more, the determination unit 4 steps. The process of step S10 is executed instead of the process of S9.

Hereinafter, an example of the operation of the human detection system 10 according to the present embodiment will be described with reference to FIG. In the example of FIG. 6, it is assumed that the person 91 enters the detection space 90 at the time t1 and the person 91 leaves the detection space 90 at the time t4.

FIG. 6 shows the output signal V1, the first flag F1, the evaluation value Vi1, the second flag F2, and the third flag F3 in order from the top with the horizontal axis as the time axis. The first flag F1 becomes “H” (High) while the standby timer 42 counts the standby time T1, and becomes “L” (Low) when the standby timer 42 does not count the standby time T1. The second flag F2 is a tentative flag representing a comparison result between the evaluation value Vi1 in the determination unit 4 and the second threshold value Vth2. The second flag F2 becomes “H” (High) when the evaluation value Vi1 is less than the second threshold value Vth2, and becomes “L” (Low) when the evaluation value Vi1 is equal to or more than the second threshold value Vth2. The third flag F3 represents the determination result of the determination unit 4. The third flag F3 becomes “H” (High) when the determination unit 4 determines that it exists, and becomes “L” (Low) when the determination unit 4 determines that it is absent. Further, in FIG. 6, “M1” represents a period in which the operation mode of the determination unit 4 is the approach detection mode, “M3” represents a period in which the operation mode of the determination unit 4 is the standby mode, and “M2” represents a determination. The operation mode of the part 4 represents a period in which the stay detection mode is used. Further, "Ti1", "Ti2", "Ti3" ... Represent the integration target period, that is, the period to be the target of the moving integration by the integration unit 6.

In the example of FIG. 6, for the period before the time t1, the determination unit 4 is operating in the approach detection mode, the determination result of the determination unit 4 is absent, and the third flag F3 is “L”. .. At time t1, since the amplitude of the output signal V1 becomes equal to or higher than the first threshold value Vth1, the determination unit 4 determines that the existence state is present, and the third flag F3 becomes “H”. At this time, the operation mode of the determination unit 4 is switched from the approach detection mode to the standby mode.

Since the determination unit 4 operates in the standby mode during the period from time t1 to time t2, the first flag F1 becomes “H”. At the time t2 when the standby timer 42 finishes counting the standby time T1, since the amplitude of the output signal V1 is less than the first threshold value Vth1, the operation mode of the determination unit 4 is switched from the standby mode to the stay detection mode. At this time, the first flag F1 becomes “L”.

The determination unit 4 starts comparing the evaluation value Vi1 with the second threshold value Vth2 at any time from the time t3 when the integration timer 41 finishes counting the integration time Ti1. At time t3, the integration unit 6 performs integration for the integration target period Ti1, and the evaluation value Vi1 obtained as a result and the second threshold value Vth2 are compared by the determination unit 4. At time t3, since the evaluation value Vi1 is less than the second threshold value Vth2, the second flag F2 becomes “H”, and the delay timer 43 starts counting the delay time T2. After that, at a time t4 before the delay timer 43 finishes counting the delay time T2, the output signal V1 fluctuates and the evaluation value Vi1 becomes equal to or higher than the second threshold value Vth2. "become.

After that, if the output signal V1 does not fluctuate significantly, the evaluation value Vi1 becomes less than the second threshold value Vth2 at the time t5 when the integration time elapses. Therefore, at time t5, the second flag F2 becomes “H”, and the delay timer 43 starts counting the delay time T2. After that, if the output signal V1 does not fluctuate significantly, the determination unit 4 determines that the output signal V1 is absent at the time t6 when the delay timer 43 finishes counting the delay time T2, and the third flag F3 becomes “L”. At this time, the operation mode of the determination unit 4 is switched from the stay detection mode to the approach detection mode.

( 3 ) Advantages As described above, the person detection system 10 according to the present embodiment includes a light receiving unit 3 and a determination unit 4. The light receiving unit 3 has a light receiving element 11 that outputs a signal corresponding to a change in the light receiving intensity of infrared rays from the detection space 90. Based on the output signals V1 and V2 of the light receiving unit 3, the determination unit 4 determines that the state of the detection space 90 is an existence state in which a person 91 exists in the detection space 90 and an absence state in which no person exists in the detection space 90. Determine which is the case. The operation mode of the determination unit 4 includes an approach detection mode for detecting the presence / absence of the entry of the person 91 into the detection space 90 and a stay detection mode for detecting the presence / absence of the exit of the person 91 from the detection space 90. In the approach detection mode, the determination unit 4 determines that the existence state is satisfied if the comparison result between the amplitude of the output signal V1 and the first threshold value Vth1 satisfies the first determination condition. In the stay detection mode, the determination unit 4 has a second comparison result between the evaluation value Vi1 and the second threshold value Vth2, which are values obtained from the output signals V1 and V2 and correspond to the movement of the person 91 in the detection space 90. It is configured to determine the absence state if the determination condition is satisfied.

According to the above configuration, the operation modes of the determination unit 4 are an approach detection mode for detecting the presence / absence of the entry of the person 91 into the detection space 90 and a stay detection mode for detecting the presence / absence of the exit of the person 91 from the detection space 90. And is included. That is, the determination unit 4 determines whether or not the state of the detection space 90 is in the existing state in the approach detection mode, and determines whether or not the state of the detection space 90 is in the absent state in the stay detection mode. .. In this way, the determination unit 4 detects the change from the absence state to the existence state and the change from the existence state to the absence state in different operation modes. Therefore, for example, if the determination unit 4 has higher sensitivity in the stay detection mode than in the approach detection mode, it is less likely that the detection omission of a person's fine movement (movement, etc.) occurs in the stay detection mode, and erroneous detection occurs in the approach detection mode. Occurrence can be suppressed.

Moreover, in the approach detection mode, the determination unit 4 determines whether or not the existence state is present based on the comparison result between the amplitude of the output signal V1 and the first threshold value Vth1. On the other hand, in the stay detection mode, the determination unit 4 is based on a comparison result between the evaluation value Vi1 and the second threshold value Vth2, which are values obtained from the output signals V1 and V2 and correspond to the movement of the person 91 in the detection space 90. To determine whether or not it is absent. That is, the algorithm of the determination processing of the determination unit 4 is different between the approach detection mode and the stay detection mode. Therefore, for example, in the stay detection mode, by applying an algorithm suitable for detecting the fine movement of the person 91, the omission of detection of the fine movement of the person 91 is less likely to occur.

Further, the multiplication unit 5 and the integration unit 6 are stopped while the operation mode of the determination unit 4 is in the approach detection mode. Therefore, the power consumption in the detection circuit 2 can be suppressed lower in the approach detection mode than in the stay detection mode.

Further, as in the present embodiment, the evaluation value Vi1 is preferably an integrated value of the output signal. However, in the present embodiment, since the "output signal" includes the output signal V1 and the output signal V2, the evaluation value Vi1 is an integral value of the multiplication values of the output signals V1 and V2. According to this configuration, in the stay detection mode, the determination unit 4 determines whether or not the person 91 exists based on the integrated value, not the instantaneous value of the output signals V1 and V2. Therefore, for example, even when the person 91 is slightly moving due to breathing, the slight movement (fine movement) is periodically repeated, so that the determination unit 4 can easily determine that the person 91 is present. However, the fact that the evaluation value Vi1 is the integral value of the output signal is not an essential configuration for the person detection system 10, and the evaluation value Vi1 is a value obtained from the output signals V1 and V2, and the movement of the person 91 in the detection space 90. It may be a value according to.

Further, as in the present embodiment, it is preferable that the first determination condition is that the amplitude of the output signal V1 is equal to or greater than the first threshold value Vth1. According to this configuration, in the approach detection mode, the determination unit 4 determines the existence state as soon as the amplitude of the output signal V1 reaches the first threshold value Vth1. Therefore, for example, when the person 91 enters the detection space 90, the lighting fixture 81 can be turned on immediately.

Further, as in the present embodiment, it is preferable that the determination unit 4 is configured to switch the operation mode from the stay detection mode to the approach detection mode when the absence state is determined in the stay detection mode. According to this configuration, when the person 91 moves from the detection space 90 to the outside of the detection space 90, the operation mode of the determination unit 4 detects the presence or absence of the person 91 entering from the detection space 90. It will switch to the detection mode. However, the configuration in which the determination unit 4 automatically switches the operation mode from the stay detection mode to the approach detection mode is not essential to the human detection system 10, and can be omitted as appropriate.

Further, as in the present embodiment, the operation mode of the determination unit 4 preferably further includes a standby mode. In this case, when the determination unit 4 determines that the existence state is present in the approach detection mode, it is preferable to switch the operation mode from the approach detection mode to the standby mode. Further, if the amplitude of the output signal V1 is less than the first threshold value Vth1 when the predetermined standby time T1 elapses from the time when the operation in the standby mode is started, the determination unit 4 stays in the operation mode from the standby mode. It is preferably configured to switch to the detection mode.

According to this configuration, when the person 91 moves from outside the detection space 90 into the detection space 90, the operation mode of the determination unit 4 detects whether or not the person 91 has left the detection space 90. It will automatically switch to the detection mode. Moreover, since the operation mode of the determination unit 4 is switched from the approach detection mode to the stay detection mode via the standby mode, the operation mode does not shift to the stay detection mode immediately after the person 91 makes a large movement. The multiplication unit 5 and the integration unit 6 are stopped while the operation mode of the determination unit 4 is in the standby mode. Therefore, the power consumption in the detection circuit 2 can be suppressed lower in the standby mode than in the stay detection mode. However, the configuration in which the determination unit 4 automatically switches the operation mode from the approach detection mode to the stay detection mode via the standby mode is not essential to the human detection system 10, and can be omitted as appropriate.

In this case, as in the present embodiment, when the amplitude of the output signal V1 becomes equal to or higher than the third threshold value (first threshold value Vth1 in the present embodiment) in the stay detection mode, the determination unit 4 detects the stay in the operation mode. It is preferably configured to switch from mode to standby mode. According to this configuration, when the determination unit 4 is operating in the stay detection mode, for example, when a large movement (walking, etc.) of the person 91 occurs, the operation mode of the determination unit 4 is automatically switched to the standby mode. Therefore, for example, regardless of whether the person 91 only passes through the detection space 90 or the person 91 leaves the detection space 90 after staying in the detection space 90, the determination unit 4 will perform after the person 91 leaves. The operation starts from the standby mode. Therefore, after the person 91 leaves the detection space 90, the variation in the time required for the determination unit 4 to determine the absence state can be suppressed to a small extent.

Further, as in the present embodiment, the second determination condition is that the evaluation value Vi1 is the second threshold value Vth2 from the time when the evaluation value Vi1 becomes less than the second threshold value Vth2 until the predetermined delay time T2 elapses. It is preferable that the state of less than is continued. According to this configuration, in the stay detection mode, the determination unit 4 does not immediately determine the absence state even if the evaluation value Vi1 becomes less than the second threshold value Vth2. Therefore, for example, when the person 91 is present in the detection space 90, it becomes difficult to turn off the lighting fixture 81.

( 4 ) Modified Example FIG. 7 is an explanatory diagram conceptually showing the operation of the determination unit 4 of the human detection system 10 according to the first modified example of the first embodiment. Since FIG. 7 is a conceptual diagram similar to that of FIG. 5, detailed description thereof will be omitted.

The person detection system 10 according to the first modification is different from the person detection system 10 according to the first embodiment in that the determination unit 4 does not have a function of switching the operation mode from the stay detection mode to the standby mode. In the first modification, once the operation mode of the determination unit 4 is switched from the standby mode (step S4) to the stay detection mode (step S6), the operation mode of the determination unit 4 is directly switched to the standby mode. There is no such thing. That is, the operation of the determination unit 4 in the stay detection mode is either to continue the operation in the stay detection mode (step S9) or to shift to the approach detection mode (step S1) (step S8). In the first modification, if the operation mode of the determination unit 4 is in the stay detection mode, it is not necessary to compare the amplitude of the output signal V1 with the first threshold value Vth1.

FIG. 8 is an explanatory diagram conceptually showing the operation of the determination unit 4 of the human detection system 10 according to the second modification of the first embodiment. Since FIG. 8 is a conceptual diagram similar to that of FIG. 5, detailed description thereof will be omitted.

The person detection system 10 according to the second modification is different from the person detection system 10 according to the first embodiment in that the operation mode of the determination unit 4 does not include the standby mode. In the second modification, the determination unit 4 is configured to switch the operation mode from the approach detection mode to the stay detection mode when it is determined that the presence state is present in the approach detection mode. That is, the operation mode of the determination unit 4 is directly switched from the approach detection mode (step S1) to the stay detection mode (step S6) (step S3). In the second modification, if the operation mode of the determination unit 4 is in the stay detection mode, it is not necessary to compare the amplitude of the output signal V1 with the first threshold value Vth1.

Hereinafter, other modified examples of the first embodiment will be listed.

The human detection system 10 is not limited to residential use, and may be used not only for residential use but also for non-residential use such as offices, stores, and factories. Further, the human detection system 10 is not limited to indoor use, and may be used outdoors.

Further, the detection result of the human detection system 10 is not limited to the control of the lighting equipment, and may be used for the control of electrical equipment other than the lighting equipment such as a ventilation fan or a security camera. Further, the detection result of the person detection system 10 is not limited to the control of the electric device, and may be used for, for example, monitoring the position of the person 91.

Further, the first determination condition, that is, the condition for the determination unit 4 to determine the existence state in the approach detection mode is not limited to the amplitude of the output signal V1 being equal to or greater than the first threshold value Vth1. For example, the first determination condition may be that the number of times the amplitude of the output signal V1 exceeds the first threshold value Vth1 reaches a predetermined number of times within a predetermined period. Further, the determination unit 4 compares the amplitude of at least one of the output signal V1 of the first light receiving unit 31 and the output signal V2 of the second light receiving unit 32 with the first threshold value Vth1 in the approach detection mode. Based on this, it may be determined whether or not it exists. For example, the determination unit 4 determines whether or not the existence state is present based on the comparison result between the amplitudes of both the output signal V1 of the first light receiving unit 31 and the output signal V2 of the second light receiving unit 32 and the first threshold value Vth1. You may judge. Alternatively, the determination unit 4 may determine whether or not it is in the existence state based on the comparison result between the amplitude of the output signal V2 of the second light receiving unit 32 and the first threshold value Vth1.

Further, the second determination condition, that is, the condition for the determination unit 4 to determine the absence state in the stay detection mode, is evaluated from the time when the evaluation value Vi1 becomes less than the second threshold value Vth2 until the delay time elapses. The state in which the value Vi1 is less than the second threshold value Vth2 does not necessarily continue. For example, the second determination condition may be that the evaluation value Vi1 is less than the second threshold value Vth2. That is, the off-delay function is not an essential function for the determination unit 4, and the determination unit 4 may determine that the determination unit 4 is absent when the evaluation value Vi1 becomes less than the second threshold value Vth2 in the stay detection mode. .. However, this configuration is the same as the configuration in which the delay time is set to zero in the configuration of the first embodiment.

Further, the operation mode of the determination unit 4 may include a delay mode as an operation mode for realizing the off-delay function in the determination unit 4, in addition to the stay detection mode. In this case, the determination unit 4 does not immediately determine the absence state even if the comparison result between the evaluation value Vi1 and the second threshold value Vth2 satisfies the second determination condition in the stay detection mode. That is, the determination unit 4 sets a temporary absence flag, switches the operation mode from the stay detection mode to the delay mode, and starts counting the delay time. The operation of the determination unit 4 in the delay mode is the same as the operation of the determination unit 4 during counting the delay time in the person detection system 10 according to the first embodiment.

Further, the off-delay function may be realized not by the determination unit 4 but by a subsequent stage of the determination unit 4, for example, the output unit 7. In this case, the determination unit 4 immediately determines the absence state when the comparison result between the evaluation value Vi1 and the second threshold value Vth2 satisfies the second determination condition in the stay detection mode. When the output unit 7 receives the determination result of the determination unit 4 that it is in the absence state, the output unit 7 starts counting the delay time.

Further, the detection spaces 90 that receive infrared rays between the first light receiving unit 31 and the second light receiving unit 32 do not have to completely coincide with each other, and may be displaced from each other. In this case, there is a possibility that a phase difference may occur between the detection component included in the output signal V1 of the first light receiving unit 31 and the detection component included in the output signal V2 of the second light receiving unit 32. In this case, the multiplication result of the multiplication unit 5 is not always a positive value, and may be a negative value. Therefore, a negative threshold value may be set in addition to the second threshold value Vth2 as a comparison target of the evaluation value Vi1. In this case, the determination unit 4 may determine whether or not the person 91 exists based on the comparison result between the evaluation value Vi1 and the negative threshold value.

(Embodiment 2)
The person detection system 10 according to the present embodiment is different from the person detection system 10 of the first embodiment in that the light receiving unit 3 has only the first light receiving unit 31. Hereinafter, the same configurations as those in the first embodiment will be designated by a common reference numeral and description thereof will be omitted as appropriate.

In the approach detection mode, the determination unit 4 is similar to the person detection system 10 of the first embodiment, based on the comparison result between the amplitude of the output signal V1 of the first light receiving unit 31 and the first threshold value Vth1. Determines if is present. On the other hand, in the stay detection mode, the determination unit 4 uses the integrated value of the multiplication result of the output signal V1 of the first light receiving unit 31 and the reference signal as the evaluation value Vi1. That is, the evaluation value Vi1 is a value obtained by multiplying the output signal V1 of the first light receiving unit 31 and the reference signal by the multiplication unit 5, and integrating the multiplication result by the integration unit 6. The reference signal referred to here is, for example, a sine wave having a frequency (for example, 0.3 Hz and 0.5 Hz) corresponding to the fine movement of the person 91. Further, the reference signal may be, for example, a signal having substantially the same phase as the output signal V1 of the first light receiving unit 31 in which the output signal V1 of the first light receiving unit 31 is shifted by a predetermined time.

As described above, in the human detection system 10 according to the present embodiment, even if the light receiving unit 3 is only the first light receiving unit 31, the determination unit 4 operates in two operation modes, an approach detection mode and a stay detection mode. It is possible.

The configuration of the person detection system 10 according to the second embodiment can be appropriately combined with the configuration of the first embodiment (including a modification).

Further, in each of the above embodiments (including modified examples), in the comparison between the two values such as the amplitude and the threshold value, the place where "or more" is set is the case where the two values are equal and the case where one of the two values exceeds the other. It means to include both the case and the case. However, not limited to this, "greater than or equal to" may be synonymous with "greater than" including only the case where one of the two values exceeds the other. That is, whether or not the two values are equal can be arbitrarily changed depending on the setting of the threshold value and the like, so there is no technical difference between "greater than or equal to" and "greater than". Similarly, "less than" may be synonymous with "less than or equal to".

10 people detection system 3 light receiving unit 11 light receiving element 4 judgment unit 90 detection space 91 people T1 standby time T2 delay time
Vi1 evaluation value Vth1 first threshold (third threshold)
Vth2 second threshold

Claims (8)

A light receiving unit having a light receiving element that outputs a signal according to a change in the light receiving intensity of infrared rays from the detection space, and a light receiving unit.
Based on the output signal of the light receiving unit, a determination unit that determines whether the state of the detection space is an existence state in which a person exists in the detection space or an absence state in which no person exists in the detection space. With and
The operation mode of the determination unit includes an approach detection mode for detecting the presence / absence of a person entering the detection space and a stay detection mode for detecting the presence / absence of a person leaving the detection space.
The determination unit
In the approach detection mode, the presence or absence of a person entering the detection space is detected based on whether or not the first determination condition is satisfied based on the output signal of the light receiving unit.
In the stay detection mode, based on the output signal of the light receiving unit, the presence or absence of a person leaving the detection space is detected depending on whether or not the second determination condition is satisfied.
The first determination condition and the second determination condition are different from each other.
A human detection system in which, as the second determination condition in the stay detection mode, a determination condition relating to a time integral value of an output signal of the light receiving unit in the cycle of human respiration or longer is used. The person detection system according to claim 1, wherein the time integral value of the output signal of the light receiving unit is a moving integrated value of the output signal of the light receiving unit. In the approach detection mode, the determination unit determines that the existence state is satisfied if the comparison result between the amplitude of the output signal of the light receiving unit and the first threshold value satisfies the first determination condition.
The first determination condition is
The person detection system according to claim 1 or 2, wherein the amplitude of the output signal of the light receiving unit is equal to or greater than the first threshold value. The determination unit
The person detection system according to any one of claims 1 to 3, which is configured to switch the operation mode from the stay detection mode to the approach detection mode when the absence state is determined in the stay detection mode. The determination unit
The person detection system according to any one of claims 1 to 4, which is configured to switch the operation mode from the approach detection mode to the stay detection mode when the presence state is determined in the approach detection mode. In the approach detection mode, the determination unit determines that the existence state is present if the amplitude of the output signal of the light receiving unit is equal to or greater than the first threshold value.
The operation mode of the determination unit further includes a standby mode.
The determination unit
When it is determined in the approach detection mode that the existence state is determined, the operation mode is switched from the approach detection mode to the standby mode.
If the amplitude of the output signal of the light receiving unit is less than the first threshold value when a predetermined standby time elapses from the time when the operation in the standby mode is started, the operation mode is changed from the standby mode to the stay. The person detection system according to any one of claims 1 to 4, which is configured to switch to the detection mode. The determination unit
The person according to claim 6, wherein when the amplitude of the output signal of the light receiving unit becomes equal to or higher than a third threshold value in the stay detection mode, the operation mode is switched from the stay detection mode to the standby mode. Detection system. In the stay detection mode, the determination unit is a value obtained from the output signal of the light receiving unit, and the comparison result between the evaluation value according to the movement of a person in the detection space and the second threshold value is the second determination. If the conditions are met, it is determined that the person is absent, and
The second determination condition is
Any of claims 1 to 7, wherein the state in which the evaluation value is less than the second threshold value continues from the time when the evaluation value becomes less than the second threshold value until a predetermined delay time elapses. The person detection system described in item 1.

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