JP2008298602A - Human body sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To discriminate a leaving person from a stationary human body in an environment with residual heat. <P>SOLUTION: A human body sensor 1 includes a processing part 5 for determining whether a human body is present based on temperature information output from an infrared detection element 3 having a detection area specified and an output part 7 for outputting a signal according to the determination of the processing part 5. The processing part 5 has a detection determination means 13 and a non-detection determination means 14. The means 13 determines presence of the human body when a change is observed in the temperature information. The means 14 determines absence of the human body when a variation state with the temperature information kept within a predetermined range succeeds for a predetermined time. The output part 7 outputs a detection signal when the means 13 determines the presence of the human body, and outputs a non-detection signal when the means 14 determines the absence of the human body. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a human body detector that detects presence / absence (presence / absence) of a human body in a detection area using an infrared detection element such as a thermopile or a thermistor bolometer that outputs an electrical signal corresponding to the amount of incident infrared rays.

Conventionally, various forms of human body detectors have been proposed and put into practical use for detecting whether or not a person is present in a preset detection area. As an example of this type of human body detector, in Patent Document 1 below, a temperature change is detected from an incident amount of infrared rays obtained using an infrared sensor element having a DC characteristic such as a thermopile or a thermistor bolometer, and within a certain time. There has been proposed an infrared detecting device that determines that a person is detected when a temperature change is detected and determines that a person is not detected when a temperature change within a certain time is not detected.
Japanese Unexamined Patent Publication No. 1-111485

  By the way, this kind of human body detector is installed in various places according to the detection area, but it is installed so as to monitor a place where a person sits on a chair and works as a detection area, such as an automatic contract machine. Sometimes. In this case, even if a person leaves the detection area after completing a series of operations, heat may remain in the chair on which the person was sitting for a while (residual heat).

  And in such an environment where residual heat exists in the detection area and in an environment where there is no residual heat, the state of temperature change in the detection area after the person leaves is different, so detection is performed with a conventional human body detector. If it does, there will be a difference in the time from when the person leaves the room until the sensor output stabilizes.

  This phenomenon will be described with reference to FIG. In FIG. 8, the vertical axis indicates the magnitude of temperature data (sensor output) obtained from the infrared detection element, and the horizontal axis indicates the passage of time. FIG. 8 shows a change in temperature data in a situation where a person enters the detection area, stays in the detection area for a while and stops, and then exits.

  First, in a state where the detection area is unattended (the state (A) in the figure), the sensor output hardly changes and is in a stable state. Then, when a person enters the detection area (time (A) in the figure), the sensor output shows a rapid change. After that, in the state where the person stays in the detection area and is stationary (the state of (c) in the figure), since the person operates the device etc., the sensor output is not as much as when the person enters. The change is larger than the state of. In this way, until the person enters and stays in the detection area, there is no significant difference in the temperature change state between the environment where the residual heat exists in the detection area and the environment where the residual heat does not exist.

  However, when a person leaves the detection area (time (D) in the figure) and thereafter (state (D) in the figure), there is a time difference until the sensor output is stabilized depending on the presence or absence of residual heat. That is, in the state where there is no residual heat, as indicated by the solid line in FIG. 8, the sensor output after leaving the detection area is stabilized in a relatively short time, whereas in the state where there is residual heat, the broken line in FIG. As shown, it takes time for the sensor output after leaving the detection area to stabilize. As a result, in the conventional human body detector, if there is residual heat in the detection area, the sensor output after exiting will not be stable, and while there is residual heat, the residual human body will remain stationary (state (c) in the figure) There is a problem that it becomes difficult to distinguish between and leaving, and the detection of exit becomes slow.

  Therefore, in order to solve the above-described problems, the present invention prevents the influence of the residual heat after the person leaves the detection area, and prevents the person from leaving the stationary human body even in an environment where the detection area has residual heat. It is an object to provide a human body detector that can be detected separately.

In order to achieve the above object, a human body detector according to claim 1 of the present invention includes a processing unit that determines presence / absence of a human body based on temperature information output from an infrared detection element in which a detection area is set, In a human body detector provided with an output unit that outputs a signal according to the determination of the processing unit,
A storage unit for sequentially storing the temperature information;
The processor is
Detection determination means for determining the presence of a human body when determining a change in the temperature information;
Non-detection determining means for determining the absence of a human body when it is determined that a fluctuation state in which the temperature information is within a predetermined range has continued for a predetermined time based on the temperature information stored in the storage unit;
The output unit outputs a detection signal when the presence of the human body is determined by the detection determination unit, and outputs a non-detection signal when the absence of the human body is determined by the non-detection determination unit. Features.

The human body detector according to claim 2 is the human body detector according to claim 1,
Further, the storage unit stores a detection state when the presence of the human body is determined by the detection determination unit, and stores a non-detection state when the absence of the human body is determined by the non-detection determination unit,
The processor is
When the detection state is stored in the storage unit, the non-detection determination unit executes determination. When the non-detection state is stored in the storage unit, the detection determination unit executes determination by the detection determination unit. Means are provided.

The human body detector according to claim 3 is the human body detector according to claim 1 or 2,
The predetermined range includes a first predetermined range that does not include fluctuation due to a stationary human body, and a second predetermined range that is wider than the first predetermined range including fluctuation due to residual heat,
The predetermined time includes a first predetermined time for detecting the absence of a stationary human body and a second predetermined time for detecting the presence of residual heat longer than the first predetermined time,
The non-detection determining means includes
First non-detection determining means for determining absence of a human body based on the first predetermined range and the first predetermined time, and first non-detection determining means for determining absence of a human body based on the second predetermined range and the second predetermined time. 2 non-detection judging means.

The human body detector according to claim 4 is the human body detector according to claim 3,
The first predetermined range is that the magnitude of the difference between the maximum value and the minimum value of the temperature information in the first predetermined period is equal to or less than a threshold value.
The second predetermined range is characterized in that the magnitude of the difference between the maximum value and the minimum value of the temperature information in a second predetermined period shorter than the first predetermined period is equal to or less than the threshold value.

  According to the human body detector according to the present invention, when determining the presence of a human body in the detection area, it is determined only by determining the change in temperature information, whereas when determining the absence of a human body in the detection area. Because the state of temperature information fluctuation and the continuity of the state are determined, the presence of the human body can be facilitated, while the absence of the human body can be carefully determined, and there is a stationary human body even when there is residual heat Nevertheless, it can be prevented that the user is mistakenly determined to be absent.

Hereinafter, the human body detector according to the present invention will be described with reference to the drawings.
First, the configuration of the human body detector according to the present invention will be described with reference to the block configuration diagram of FIG.

  The human body detector 1 of this example detects the presence / absence (presence / absence) of a human body in a detection area to be monitored, and is intended to prevent the influence of residual heat in the detection area after a person leaves. As shown in FIG. 1, an optical system 2, an infrared detection element 3, an amplifier circuit 4, a processing unit 5, a storage unit 6, and an output unit 7 are schematically configured.

  The optical system 2 is composed of, for example, a lens, a mirror, and the like, and condenses infrared rays emitted from a preset detection area on the infrared detection element 3.

  The infrared detection element 3 detects infrared rays from a detection area collected by the optical system 2, and is composed of, for example, a thermopile, a thermistor bolometer, or the like, and generates an electrical signal proportional to the amount of infrared light received from the detection area. Output. In this embodiment, the detection area is divided into four areas, and the infrared rays emitted from the divided detection areas are detected by the four infrared detection elements 3, respectively. In addition, although the example which provided four infrared rays detection elements 3 was shown in FIG. 1, what is necessary is just to provide an appropriate number according to the installation reference | standard of the human body detector 1, etc. FIG.

  The amplifier circuit 4 amplifies the electrical signal from the infrared detection element 3 and outputs the amplified electrical signal to the processing unit 5. The amplification circuit 4 is connected to the infrared detection element 3 in a one-to-one correspondence. In the example of FIG. 1, one amplification circuit 4 is connected to each of the four infrared detection elements 3.

  The processing unit 5 processes the electrical signal from each amplifier circuit 4 and determines the presence / absence (presence / absence) of a human body in the detection area based on the processing result. And this process part 5 is the data acquisition means 11 which acquires temperature information from each infrared rays detection element 3, the detection state determination means 12 which determines the presence or absence state of the present human body, the detection determination means 13 which determines presence of a human body, The non-detection determination unit 14 is configured to determine the absence of a human body.

  The data acquisition means 11 samples the electrical signal from each amplifier circuit 4 for each infrared detection element 3 at a predetermined sampling interval (for example, every 0.1 second), and receives the infrared rays received by each infrared detection element 3. A sampling value (temperature information) that is data proportional to the amount is acquired. The sampling value acquired by the data acquisition unit 11 is stored for each infrared detection element 3 in the storage unit 6 described below.

Here, the storage unit 6 will be described.
As shown in FIG. 1, the storage unit 6 includes a current state storage area 6a and a data storage area 6b. The current state storage area 6a stores information indicating the presence / absence state of the current human body by the human body detector 1 at every predetermined interval (sampling period).

  Specifically, in the current state storage area 6a, “detection state” information indicating that a human body exists when the detection determination unit 13 determines the presence of the human body is stored. In addition, when the non-detection determination unit 14 determines the absence of a human body, information of “non-detection state” indicating that no human body exists is stored.

  In the data storage area 6b, the sampling values acquired by the data acquisition unit 11 are sequentially accumulated and stored for each infrared detection element 3.

  The detection state determination means 12 determines the presence / absence state of the current human body of the human body detector 1 stored in the current state storage area 6a. Specifically, if the information stored in the current state storage area 6a is “detection state”, the current state is determined as the detection state. If the information stored in the current state storage area 6a is “non-detection state”, the current state is determined as the non-detection state.

  The detection determination unit 13 is a unit that functions as a detection determination logic that determines the presence of a human body in the detection area. When the detection determination unit 13 determines the change in the sampling value acquired by the data acquisition unit 11, the detection determination unit 13 determines the presence of the human body. Specifically, the detection determination unit 13 compares the sampling value sampled by the data acquisition unit 11 in any one of the plurality of infrared detection elements 3 with a predetermined time (for example, 0.5 When the absolute value (change value) of the difference from the sampled value sampled two seconds ago is equal to or greater than a value indicating a predetermined temperature change (for example, 1 ° C.), the presence of the human body (with human body) is determined. Yes. In addition, when the detection determination unit 13 determines the presence of a human body, the detection unit 13 causes the storage unit 6 to store “detection state” information indicating that the human body exists.

  The non-detection determination unit 14 is a unit that functions as a non-detection determination logic that determines the absence of a human body in the detection area. The non-detection determination unit 14 determines the absence of a human body in the detection area when it is determined that the fluctuation state in which the sampling value acquired by the data acquisition unit 11 is within a predetermined range has continued for a predetermined time. That is, the non-detection determination unit 14 determines the absence of the human body by determining that the sequentially acquired sampling values are fluctuating within a predetermined range and that the state is continuing. On the other hand, the above-described detection determination unit 13 determines the presence of the human body by determining a change in the sampling value. Thereby, in the determination of the absence of the human body, the non-detection determination unit 14 determines the continuation of the state in addition to the determination of the fluctuating state, so the determination of the absence that distinguishes the residual heat from the stationary human body is performed. It becomes possible.

  The non-detection determination unit 14 includes a fluctuation determination unit 14a that functions as a normal exit logic and a short fluctuation determination unit 14b that functions as a residual heat countermeasure exit logic. The fluctuation determination unit 14a and the short fluctuation determination unit 14b execute a process of determining the absence of a human body in parallel.

  The fluctuation determination unit (first non-detection determination unit) 14a calculates a “fluctuation value” based on the sampling value acquired by the data acquisition unit 11, and the sampling value is within a predetermined range based on the “fluctuation value” ( It is determined whether the state is within a first predetermined range. The “fluctuation value” referred to here is an absolute value of a difference between the maximum value and the minimum value of the sampling value in the first predetermined period t1 (for example, t1 = 10 seconds) retroactive from the time of calculation. The fluctuation determination unit 14a reads the sampling value stored in the data storage area 6b, calculates the “fluctuation value”, and if the calculated “fluctuation value” is equal to or less than the threshold, the sampling value is within a predetermined range (first In the predetermined range). Then, it is determined whether or not this determination continues for a first predetermined time T1 (for example, T1 = 60 seconds), and the absence of a human body is determined when continuation is determined for all the infrared detection elements 3. In this example, for example, a value indicating about 0.3 ° C. is preset as a threshold value. Further, when the fluctuation determination unit 14 a determines the absence of the human body, the fluctuation determination unit 14 a causes the storage unit 6 to store “non-detection state” information indicating that no human body exists.

  The short fluctuation determination means (second non-detection determination means) 14b calculates a “short fluctuation value” based on the sampling value acquired by the data acquisition means 11, and the sampling value is determined based on the “short fluctuation value”. It is determined whether the state fluctuates within the range (within the second predetermined range). The “short fluctuation value” here refers to a maximum value and a minimum value of sampling values in a second predetermined period t2 (for example, t2 = 0.4 seconds) shorter than the first predetermined period t1 retroactively from the calculation time. Is the absolute value of the difference. The short fluctuation determination unit 14b reads the sampling value stored in the data storage area 6b to calculate the “short fluctuation value”. If the calculated “short fluctuation value” is equal to or less than the threshold value, the sampling value is within the predetermined range. It is determined that the state fluctuates (within the second predetermined range). Then, it is determined whether this determination continues for a second predetermined time T2 (for example, T2 = 90 seconds) longer than the first predetermined time T1, and when it is determined that all infrared detection elements 3 are to be continued, Judging by absence. Further, when the short fluctuation determination unit 14 b determines the absence of the human body, the short fluctuation determination unit 14 b stores information on the “non-detection state” indicating that the human body does not exist in the storage unit 6.

  In this example, in the determination of “fluctuation value” and “short fluctuation value”, the determination period is made different (predetermined period t1> predetermined period t2), and the threshold value is set to the same value.

  Here, with reference to FIG. 2, the significance of determining with the same threshold in the determination of “fluctuation value” and “short fluctuation value” will be described.

FIG. 2 is a diagram showing the relationship between the sampling value and the calculated “fluctuation value” and “short fluctuation value”. FIG. 2 shows, in order from the leftmost column, the time (t _n ) when the data acquisition unit 11 samples, the sampling value (° C.) sampled by the data acquisition unit 11, and the “fluctuation value” calculated by the fluctuation determination unit 14 a. The “short fluctuation value” calculated by the short fluctuation determination means 14b is shown. A time point t _{0 in} FIG. 2 is a time point when the human body detector 1 is turned on.

First, when the power is turned on at t ₀ , the data acquisition means 11 takes a sampling value every predetermined sampling period (0.1 second) (t ₀ , t ₁ , t ₂ , t ₃ ,. Are stored in the data storage area 6b of the storage unit 6 sequentially. Immediately after the power is turned on, since the number of sampling values is insufficient, the “fluctuation value” and the “short fluctuation value” are not calculated.

When the time of t _4, the short fluctuation determination unit 14b selects a sampling value in the second predetermined period t2 back sampled value sampled at t ₄ time from that time (t2 = 0.4 s). The t ₄ time, t ₀ time t ₁ time, t ₂ time, t ₃ time points, the sampling value at t ₄ time, i.e., the 23.42,23.43,23.46,23.49,23.47 A total of 5 sampling values are selected. Next, the short fluctuation determination unit 14b selects a maximum value and a minimum value among the five sampling values. The t ₄ time, sampling values 23.49 at t ₃ time points as the maximum value, the sampling value 23.42 at t ₀ time point is selected as the minimum value. Then, the short fluctuation determination unit 14b calculates the absolute value of the difference between the selected maximum value and minimum value as the “short fluctuation value”. That is, at time t ₄ , “short fluctuation value” = | 23.49-23.42 | = 0.07.

In the same manner after time t ₄ , the short fluctuation determination unit 14 b calculates a “short fluctuation value” every time a sampling value is acquired.

When the time of t _100, the fluctuation determination unit 14a selects the sampling value in the first predetermined period t1 back sampled value sampled at t ₁₀₀ time from that time (t1 = 10 seconds). The t ₁₀₀ time, t ₀ time, t ₁ time, t ₂ time, · · ·, t ₉₈ time, t ₉₉ time, t sampled value at ₁₀₀ times, i.e., 23.42,23.43,23.46, ... A total of 101 sampling values of 23.58, 23.61, 23.60 are selected. Next, the fluctuation determination unit 14a selects a maximum value and a minimum value from among the 101 sampling values. In FIG. 2, the sampling values from the time point t _{6 to the} time point t ₉₇ are not shown, but at the time point t ₁₀₀ , the sampling value 23.61 at the time point t ₉₉ is the maximum value, and the sampling value 23.42 at the time point t ₀ is set. Is selected as the minimum value. Then, the fluctuation determination unit 14a calculates the absolute value of the difference between the selected maximum value and minimum value as the “fluctuation value”. That is, in the t ₁₀₀ point in time, "fluctuation value" = | a = 0.19 | 23.61-23.42.

t ₁₀₀ time after, in the same way, the fluctuation determination unit 14a calculates the "fluctuation value" each time to obtain the sampling value.

  As described above, since the “fluctuation value” is calculated in a longer period (t2 <t1) than the “short fluctuation value”, the number of sampling values that are the basis of calculation increases. Therefore, even if the “fluctuation value” and the “short fluctuation value” are calculated at the same time, the “fluctuation value” tends to be larger than the “short fluctuation value”. Then, since it is determined whether the “fluctuation value” and the “short fluctuation value” are equal to or less than the threshold using the same threshold value, the determination in the “fluctuation value” is a calculated value rather than the determination in the “short fluctuation value”. Tend to be determined to be less than or equal to the threshold. That is, in determining whether the sampling value is fluctuating within a predetermined range, the fluctuation determination unit 14a fluctuates within a narrower range (within the first predetermined range) than the short fluctuation determination unit 14b. Judge that it is. In other words, the short fluctuation determination unit 14b determines that the sampling value fluctuates within a wider range (within the second predetermined range) than the fluctuation determination unit 14a.

  Therefore, the fluctuation determination unit 14a determines whether or not the sampled value is fluctuating within a predetermined range more strictly than the short fluctuation determination unit 14b so as not to include fluctuation due to a stationary human body. On the other hand, the short fluctuation determination means 14b determines that the fluctuation due to residual heat is included more loosely than the fluctuation determination means 14a.

  The output unit 7 outputs the presence / absence information of the human body based on the determination results of the detection determination unit 13 and the non-detection determination unit 14 to the outside. That is, the output unit 7 outputs a detection signal indicating that the human body has entered the detection area to the outside when the detection determination unit 13 determines the presence of the human body. The output unit 7 outputs a non-detection signal indicating that the human body has left when the non-detection determination unit 14 (at least one of the fluctuation determination unit 14a and the short fluctuation determination unit 14b) determines the absence of the human body. Output to the outside.

Next, an operation performed by the processing unit 5 of the human body detector 1 having the above-described configuration at predetermined intervals (sampling periods) will be described with reference to the flowcharts of FIGS.
3 is a main flowchart of the human body detector according to the present invention, FIG. 4 is a flowchart of non-detection determination processing by the normal exit logic of the human body detector according to the present invention, and FIG. 5 is a countermeasure against residual heat of the human body detector according to the present invention. It is a flowchart of the non-detection determination process by a leaving logic.

  In the processing unit 5, the data acquisition means 11 samples the output signal from each amplifier circuit 4 connected to each infrared detection element 3 on a one-to-one basis at a predetermined sampling period, and the sampled data (sampling value) is Each infrared detection element 3 is sequentially stored in the data storage area 6 b of the storage unit 6.

Then, when the sampling period is elapsed and the sampling value is acquired, the main flowchart of FIG. 2 is started. Therefore, this main flowchart is started each time sampling is performed. First, the detection state determination unit 12 determines whether or not the current state is the detection state from the information in the current state storage area 6a of the storage unit 6 (ST1). When the information stored in the current state storage area 6a of the storage unit 6 is “non-detection state”, it is determined that the detection state is not detected (ST1-No), and the process proceeds to detection determination processing by the detection determination unit 13. In this detection determination process, data is read from the data storage area 6b of the storage unit 6 (ST2), and change values are calculated for all infrared detection elements 3 (ST3). Subsequently, it is determined whether or not the change values calculated for all infrared detection elements 3 are equal to or greater than a threshold value (ST4). If any one of the infrared detection elements 3 determines that the change value is equal to or greater than the threshold value (ST4-Yes), the detection signal is output to the output unit 7 and the “detection state” information is also output. Is stored in the current state storage area 6a of the storage unit 6 (ST5), and the process ends.
If the change value is not greater than or equal to the threshold value (ST4-No), the process of ST5 is skipped and the process ends.

  In ST1, when the information stored in the current state storage area 6a of the storage unit 6 is “detected state”, it is determined that the state is detected (detected state) (ST1-Yes), and the non-detection determining unit 14 determines that the information is not detected. The process proceeds to detection determination processing. In this non-detection determination process, the process of the normal exit logic by the fluctuation determination unit 14a and the process of the residual heat countermeasure exit logic by the short fluctuation determination unit 14b are executed in parallel.

  First, normal exit logic processing will be described with reference to FIG. In this normal exit logic processing, data for each infrared detection element 3 is read from the data storage area 6b of the storage unit 6 (ST11), and a "fluctuation value" is calculated for each infrared detection element 3 (ST12). Subsequently, it is determined whether or not all the calculated “fluctuation values” are equal to or less than a threshold value (ST13). If it is determined that all the calculated “fluctuation values” are equal to or less than the threshold value (ST13—Yes), it is determined whether the timer is being measured (ST14). If the timer is not being measured (ST14—No), the timer is started. (ST15). At this time, if the timer is already timing (ST14-Yes), the timer timing start processing is skipped. On the other hand, if it is determined that all the calculated “fluctuation values” are not less than or equal to the threshold value (ST13—No), the timer count is reset (ST16). After that, it is determined whether or not the state where the “fluctuation value” is equal to or less than the threshold value (time count time of the timer) continues for the first predetermined time T1 or more for all infrared detection elements 3 (ST17). When it is determined that the state where the “fluctuation value” is equal to or less than the threshold value has passed for the first predetermined time T1 or more for all infrared detection elements 3 (ST17—Yes), a non-detection signal is output to the output unit 7 and “non-detection” "State" is stored in the current state storage area 6a of the storage unit 6 (ST18), and the normal exit logic is terminated. Otherwise (ST17-No), ST18 is skipped and the normal exit logic is terminated.

  Next, the process of the residual heat countermeasure exit logic will be described with reference to FIG. In this residual heat countermeasure exit logic processing, data for each infrared detection element 3 is read from the data storage area 6b of the storage unit 6 (ST21), and a "short fluctuation value" is calculated for each infrared detection element 3 (ST22). ). Subsequently, it is determined whether or not all the calculated “short fluctuation values” are equal to or less than a threshold value (ST23). When it is determined that all the calculated “short fluctuation values” are equal to or less than the threshold value (ST23—Yes), it is determined whether the timer is being timed (ST24). If the timer is not being timed (ST24—No), the timer is timed. Start (ST25). At this time, if the timer is already timing (ST24-Yes), the timer timing start processing is skipped. On the other hand, if it is determined that all the calculated “short fluctuation values” are not less than or equal to the threshold value (ST23—No), the timer count is reset (ST26). Thereafter, it is determined whether or not the state in which the “short fluctuation value” is equal to or less than the threshold value (time count time of the timer) continues for the second predetermined time T2 (> T1) or more for all the infrared detection elements 3 (ST27). If it is determined that the state where the “short fluctuation value” is equal to or less than the threshold value for all the infrared detection elements 3 has passed the second predetermined time T2 (ST27—Yes), a non-detection signal is output to the output unit 7 and “ "Detected state" is stored in the current state storage area 6a of the storage unit 6 (ST28), and the residual heat countermeasure exit logic is terminated. If not (ST27-No), ST28 is skipped and the residual heat countermeasure exit logic is terminated.

  In the above description, the processing using the timer is performed when the calculated “fluctuation value” or “short fluctuation value” is equal to or less than the threshold value, but a counter may be used instead of the timer. . In this case, when all the calculated “fluctuation values” and all the “short fluctuation values” are equal to or less than the threshold value, the counter count value is incremented by 1 instead of ST14 and ST15, ST24 and ST25, and all the calculated “fluctuation values” are set. The counter is reset instead of ST16 and ST26 when at least one of "" and at least one of all "short fluctuation values" is greater than the threshold. In ST17 and ST27, when the count value of the counter is equal to or greater than the value corresponding to the first predetermined time T1 or the value corresponding to the second predetermined time T2, a non-detection signal is output and the “non-detection state” is stored. It may be stored in the current state storage area 6a of the unit 6.

Here, paying attention to one infrared detection element 3 when a human body enters and leaves the detection area, there are cases where there is no residual heat in the normal exit logic processing and the residual heat countermeasure exit logic processing. An example of the timing chart is shown in FIGS.
FIGS. 6A and 6B are examples of timing charts of non-detection determination processing by the normal exit logic of the human body detector according to the present invention, and FIGS. 7A and 7B are diagrams of the human body detector according to the present invention. It is an example of the timing chart of the non-detection determination process by the residual heat countermeasure exit logic.

  In FIG. 6, the vertical axis indicates the fluctuation value, and the horizontal axis indicates the passage of time. In FIG. 7, the vertical axis indicates the magnitude of the short fluctuation value, and the horizontal axis indicates the passage of time. FIGS. 6 and 7 show changes in the fluctuation value and the short fluctuation value in a situation where a person enters the detection area, stays in the detection area for a while, and then exits. The state before the person enters the detection area is indicated as (a), the state where the person stays in the detection area (a), and the state after the person leaves the detection area as (u). .

  In the normal exit logic processing, the “fluctuation value” which is the absolute value of the difference between the maximum value and the minimum value of the sampling value in the first predetermined period t1 longer than the second predetermined period t2 when the “short fluctuation value” is calculated. ”Is equal to or less than the same threshold value as when the“ short fluctuation value ”is determined, and the absence of the human body is determined when the first predetermined time T1 continues. Therefore, the “fluctuation value” in the normal exit logic tends to be larger than the “short fluctuation value” in the residual heat countermeasure exit logic. As shown in FIG. 6 showing the normal exit logic and FIG. 7 showing the residual heat countermeasure exit logic, the fluctuation value between the person entry and the person exit (state (A)) is compared with the short fluctuation value. In addition, it can be seen that the fluctuation value in the normal exit logic is larger than the short fluctuation value in the residual heat countermeasure exit logic, and frequently exceeds the threshold value. That is, the fine movement of the stationary human body during the period from the person entering to the person leaving (state (A)) can be reliably captured by the fluctuation state of the “fluctuation value”.

  Further, in this normal exit logic process, when there is no residual heat, as shown in FIG. 6A, after the person leaves (the state of (c)), the “fluctuation value” starts from the time when the value becomes equal to or less than the threshold value. When the state in which the temperature change is extremely small (the state where the “fluctuation value” is equal to or less than the threshold value) continues for the first predetermined time T1 shorter than the second predetermined time T2 in the residual heat countermeasure exit logic, the absence of the human body is determined. As described above, the normal exit logic can reliably detect the slight movements of the stationary human body, so the judgment of continuation of the state where the "fluctuation value" is below the threshold value is made shorter than the residual heat countermeasure exit logic. If there is no residual heat, the absence can be quickly determined.

  On the other hand, when there is residual heat, as shown in FIG. 6 (b), there is a temperature change due to the residual heat for a while even after the person leaves (the state of (c)), so the temperature change is very small. It does not become a state, but the timer that starts timing when the “fluctuation value” becomes equal to or less than the threshold value is not reset continuously and is immediately reset. Therefore, the determination of the absence of the human body is delayed. Therefore, in this example, this problem is solved by using the residual heat countermeasure exit logic process together with the normal exit logic process.

  In the residual heat countermeasure exit logic process, the “short fluctuation value” that is the absolute value of the difference between the maximum value and the minimum value of the sampling value in the second predetermined period t2 shorter than the first predetermined period t1 is “fluctuation”. The absence of the human body is determined when the state that is equal to or less than the same threshold value as in the “value” determination continues for a second predetermined time T2 that is longer than the first predetermined time T1. Therefore, the “short fluctuation value” in the residual heat countermeasure exit logic tends to be a smaller value than the “fluctuation value” in the normal exit logic. The residual heat countermeasure exit logic that uses this “short fluctuation value” to determine the stability of changes in the sampling value solves the problem that the normal exit logic delays the determination of the absence of a human body when there is residual heat. Yes. As shown in FIG. 7B, the residual heat countermeasure exit logic is such that the calculated “short fluctuation value” is “fluctuation” even when there is residual heat after the person exits (state (c)). The value tends to be smaller than “value”, and the timing of falling below the threshold is early. Therefore, in the residual heat countermeasure exit logic, if there is residual heat, as shown in FIG. 7B, the determination of continuation by the timer can be started immediately after the person exits, so that the absence determination can be performed quickly.

  However, in the residual heat countermeasure exit logic, the state in which the temperature change is small from the time when the “short fluctuation value” becomes equal to or less than the threshold (the state where the “short fluctuation value” is equal to or less than the threshold) is the first predetermined time T1 of the normal exit logic. The absence of the human body is determined by continuing the second predetermined time T2 longer than the predetermined time T2. This is because the residual heat countermeasure exit logic captures a stationary human body less frequently than the normal exit logic, as described above.

  As described above, in the human body detector 1 of this example, the processing of the detection determination logic and the processing of the non-detection determination logic are divided into functions, and at each sampling period for sampling the temperature information from each infrared detection element 3 at that time The processing of the detection determination logic or the processing of the non-detection determination logic is executed according to the state (detection state or non-detection state). Thus, when determining the presence of a human body in the detection area, it is determined only by determining the change in temperature information, whereas when determining the absence of a human body with respect to the detection area, the state of fluctuation of the temperature information and Since the continuity of the state is determined, it can be prevented that the absence is erroneously determined. As a result, even in an environment where there is residual heat in the detection area, it is possible to detect the exit of a person separately from a stationary human body.

  In this example, in order to determine the absence of a human body, a fluctuation determination unit (first non-detection determination unit) 14a that strictly determines that the temperature information fluctuates within a predetermined range, and the temperature information is predetermined. Short fluctuation determination means (second non-detection determination means) 14b for loosely determining that the fluctuation is within the range is provided, and the absence determination is executed in parallel using both means. Thus, when there is no residual heat in the detection area, the fluctuation determination means (first non-detection determination means) 14a can quickly determine the absence of the human body from the stationary human body, as well as the fluctuation determination means. (First non-detection determining means) Even when there is residual heat that cannot be readily determined by 14a, the short fluctuation determining means (second non-detection determining means) 14b performs fluctuation determining means (first non-detection determining means). (Non-detection determining means 1) 14a can continue to determine the state of fluctuation earlier than the above, so that the absence can be detected promptly even if there is a person's residual heat.

  Further, the fluctuation determination means (first non-detection determination means) 14a can strictly determine that the fluctuation is smaller than that of the short fluctuation determination means (second non-detection determination means) 14b. In addition, the short fluctuation determination means (second non-detection determination means) 14b is conditioned on the fact that the fluctuation state continues longer than that of the fluctuation determination means (first non-detection determination means) 14a. The absence can be determined without missing a small movement of the person who is doing.

  In this example, the detection determination unit 12 determines that the difference (change value) between the current sampling value and the sampling value before a predetermined time exceeds the threshold value in order to determine a change in temperature information. However, the present invention is not limited to this. For example, the determination may be made when the current sampling value itself exceeds a predetermined threshold.

  Further, in the determination of the state in which the temperature information fluctuates within the predetermined range, the shorter fluctuation determination means (second non-detection) than the first predetermined range in the fluctuation determination means (first non-detection determination means) 14a. In order to widen the second predetermined range of the determination means) 14b, the first predetermined period t1> the second predetermined period t2 and the threshold value are set to be the same. However, the present invention is not limited to this. Is not to be done. For example, the first predetermined period t1 = the second predetermined period t2, and the threshold value in the fluctuation determination unit (first non-detection determination unit) 14a is the threshold value in the short fluctuation determination unit (second non-detection determination unit) 14b. The same can be realized by setting a smaller value.

It is a block block diagram of the human body detector which concerns on this invention. It is a figure which shows the relationship between the sampling value when paying attention to one infrared rays detection element of the human body detector which concerns on this invention, and the calculated fluctuation value and short fluctuation value. It is a main flowchart of the human body detector which concerns on this invention. It is a flowchart of the non-detection determination process by the normal exit logic of the human body detector which concerns on this invention. It is a flowchart of the non-detection determination process by the residual heat countermeasure exit logic of the human body detector which concerns on this invention. (A), (b) It is an example of the timing chart of the non-detection determination process by the normal exit logic of the human body detector which concerns on this invention. (A), (b) It is an example of the timing chart of the non-detection determination process by the residual heat countermeasure exit logic of the human body detector which concerns on this invention. It is explanatory drawing which shows the difference of the change of the temperature data by the presence or absence of residual heat.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Human body detector 2 Optical system 3 Infrared detection element 4 Amplifying circuit 5 Processing part 6 Storage part 6a Current state storage area 6b Data storage area 7 Output part 11 Data acquisition means 12 Detection state determination means 13 Detection determination means 14 Non-detection determination means 14a Fluctuation determination means (first non-detection determination means)
14b Short fluctuation determination means (second non-detection determination means)

Claims (4)

In a human body detector including a processing unit that determines the presence or absence of a human body based on temperature information output from an infrared detection element in which a detection area is set, and an output unit that outputs a signal according to the determination of the processing unit ,
A storage unit for sequentially storing the temperature information;
The processor is
Detection determination means for determining the presence of a human body when determining a change in the temperature information;
Non-detection determining means for determining the absence of a human body when it is determined that a fluctuation state in which the temperature information is within a predetermined range has continued for a predetermined time based on the temperature information stored in the storage unit;
The output unit outputs a detection signal when the presence of the human body is determined by the detection determination unit, and outputs a non-detection signal when the absence of the human body is determined by the non-detection determination unit. Characteristic human body detector. Further, the storage unit stores a detection state when the presence of the human body is determined by the detection determination unit, and stores a non-detection state when the absence of the human body is determined by the non-detection determination unit,
The processor is
When the detection state is stored in the storage unit, the non-detection determination unit executes determination. When the non-detection state is stored in the storage unit, the detection determination unit executes determination by the detection determination unit. The human body detector according to claim 1, comprising means. The predetermined range includes a first predetermined range that does not include fluctuation due to a stationary human body, and a second predetermined range that is wider than the first predetermined range including fluctuation due to residual heat,
The predetermined time includes a first predetermined time for detecting the absence of a stationary human body and a second predetermined time for detecting the presence of residual heat longer than the first predetermined time,
The non-detection determining means includes
First non-detection determining means for determining absence of a human body based on the first predetermined range and the first predetermined time, and first non-detection determining means for determining absence of a human body based on the second predetermined range and the second predetermined time. The human body detector according to claim 1 or 2, comprising two non-detection determining means. The first predetermined range is that the magnitude of the difference between the maximum value and the minimum value of the temperature information in the first predetermined period is equal to or less than a threshold value.
The second predetermined range is characterized in that a magnitude of a difference between a maximum value and a minimum value of the temperature information in a second predetermined period shorter than the first predetermined period is equal to or less than the threshold value. Item 4. The human body detector according to item 3.

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