JP3569988B2 - Human body detection device - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a human body detecting device used in a device that automatically detects and detects a human body, such as an automatic faucet.
[0002]
[Prior art]
Conventionally, an automatic water supply device and a hot water cleaning device using a reflection type non-contact active sensor are already known. Particularly, in an automatic faucet, a human body detecting device is disposed on a wash basin or the like, and a spout of the wash basin is provided. There is a faucet device that automatically opens the faucet and discharges water from the spout when it detects a human body such as a hand below.This human body detection device emits light, ultrasonic waves, etc. toward the lower part of the spout. By measuring the reflection level and comparing this level with a set value, a human body present below the spout is detected.
[0003]
However, when the presence or absence of the human body is detected based on the level of the reflected wave as described above, in the case of an automatic water supply device, a hot water washing device, the surrounding wall, and in an automatic faucet, the reflection or spout of the bottom inside the bowl of the wash basin. The detection state becomes unstable due to the temporary change of the inner bottom reflectance due to the contamination of the bowl, etc., and the temporal change of the inner bottom reflectance and the sensor There is a problem that it is necessary to update the set values in order to correct deterioration and the like.
[0004]
In order to solve such a problem, the related art, for example, as disclosed in Japanese Patent Publication No. 62-45503, corresponds to the time required for the ultrasonic wave to reciprocate between the sensor and the object between the transmission clock and the reception clock of the ultrasonic wave. By setting the phase difference, the object detection distance range is limited, and the water flow and the bottom surface inside the bowl are excluded from the detection range, so that disturbance due to the water flow or the like is avoided.
[0005]
Also, in Japanese Patent Application Laid-Open No. 61-500232, the above-described disturbance is avoided by measuring the distance between the sensor and the part to be detected from the reciprocating time of the ultrasonic wave and limiting the detection distance range. I have.
[0006]
In Japanese Utility Model Laid-Open Publication No. 63-199080, the disturbance is avoided by detecting the movement of an object within a limited distance range based on the time that an ultrasonic wave reciprocates between a sensor and a detected part. .
[0007]
However, the method of limiting the detection distance range as described above requires sufficient countermeasures against disturbance, so that the device for detecting the distance has a complicated circuit configuration and is costly.
[0008]
In Japanese Utility Model Laid-Open Publication No. 63-13367, the disturbance is avoided by detecting the movement of the object from the differential of the reflection level from the object.
[0009]
However, there is a problem that it is difficult to detect a slow movement of an object, and conversely, a malfunction easily occurs due to a large change noise such as spike noise.
[0010]
In Japanese Utility Model Laid-Open Publication No. 4-26270, the movement of an object is detected by delaying a part of a received signal of a reflected wave and comparing the delayed signal with a non-delayed received signal. No countermeasures are taken against malfunctions caused by the above, and there is a problem that object detection becomes unstable.
[0011]
Further, in the above-described conventional technology, the presence or absence of a human body is detected by capturing local characteristics of a time-series pattern of the reflection level, and when an accidental level change is superimposed on the local characteristics, the human body is not detected. Nevertheless, the faucet may be activated.
[0012]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide a human body detection device using a reflection-type non-contact active sensor, which can reliably detect only the human body even when accidental level fluctuations are superimposed on local features of a time-series pattern of reflection levels. To be able to detect it.
[0013]
[Means for Solving the Problems]
According to the present invention, in a human body detection device that detects the presence or absence of a human body using a reflection type non-contact active sensor, data of a reflection signal level from the active sensor is periodically sampled, and continuous sampling including the latest data is performed. There is provided a human body detection device including a statistical calculation unit that calculates at least one type of statistical value from a plurality of pieces of data obtained, and a determination unit that determines whether a human body is present based on the statistical value.
[0014]
As the statistical value, for example, at least one of an average value, a variance value, and a standard deviation can be adopted.
[0015]
In a preferred embodiment, the average value under the condition that the variance value is smaller than a certain value is determined as a reference level indicating a state without a human body, and the comparison result between the average value and the reference level, the variance value and a predetermined value are determined. The presence or absence of a human body is determined based on a combination with the comparison result with the threshold value.
[0016]
Alternatively, the average value under the condition that the difference between the latest data and the average value is within a certain range is determined as the reference level, and the presence or absence of a human body is determined based on the comparison result between the latest data and the reference level. It can also be done.
[0017]
In order to improve responsiveness when a human body appears, it is desirable to detect a significant change in the reflected signal level from the above statistic in a state where the judgment result is that there is no human body, and to increase the sampling cycle.
[0018]
In particular, when the present invention is applied to an automatic faucet, in order to prevent erroneous detection due to fluctuation of the water discharge at the time of stopping the water discharge, a condition for determining that there is a human body immediately after the stop of the water discharge is a normal condition for determining that there is a human body. It is desirable to be stricter.
[0019]
Further, in order to prevent infinite repetition of judgment change of presence / absence of a human body due to erroneous detection in a special situation, the number of judgment changes continuously repeated at intervals shorter than a predetermined time is counted. When the count value exceeds a predetermined value, it is desirable to prohibit continuous determination change.
[0020]
One method for this prohibition is to change the count value to a stricter condition when the count value exceeds a predetermined value than before the condition for determining that there is a human body.
[0021]
[Action]
In the human body detection device of the present invention, the presence or absence of a human body is determined using the statistical value obtained from the sampling value of the reflected signal level, so that the influence of disturbance or noise included in the reflected signal component is reduced, and the presence or absence of the human body is determined. It is possible to grasp data characteristics that express various states according to the presence or absence of a foreign substance (for example, water spouting in the case of an automatic faucet or a washbasin), and reflect the data characteristics in the determination. As a result, the influence of signal reflection from foreign matter can be removed, and the presence or absence of a human body can be accurately detected.
[0022]
【Example】
Hereinafter, an embodiment of the present invention applied to an automatic faucet will be described in detail with reference to the drawings.
[0023]
FIG. 1 shows a configuration of a washing surface B provided with an embodiment of an automatic faucet A, B1 is a bowl, B2 is a spout, and the spout B2 is located on the front upper surface at the back of the washstand B. It is connected to the upper end of the base B, which is set up with a slight inclination, and is inclined downward slightly. Discharge water B4 discharged obliquely downward from the spout B2 draws a parabola and falls into the bowl B1. The electromagnetic valve B5 is interposed between the spout B2 and the water source B6 to control spouting from the spout B2.
[0024]
The object detection device is disposed inside the base B2, and is covered by a transparent window formed in the front of a middle part of the base B3.
[0025]
As shown in FIG. 2, the human body detection device S includes an optical sensor S1 as a reflection-type non-contact active sensor, an arithmetic unit S2, and an output unit S3.
[0026]
The light sensor S1 is composed of a light projecting unit S4, a light receiving unit S5, and an amplifying unit S6. The light projecting unit S4 is directed to a space below the spout B2 in a direction slightly inclined downward from the spout B2 by a small angle. Light is projected at a predetermined cycle in a range (light projection area) indicated by α in FIG. The light receiving unit S5 converts the incident light into a voltage signal and outputs the voltage signal to the amplifying unit S6. The light incident area (light receiving area) is set to a range indicated by β in FIG. Have been. The optical sensor S1 is capable of satisfactorily detecting an object existing in a range (detection area) indicated by γ in FIG. 1 where the light projection area α and the light reception area β overlap.
[0027]
Here, as shown in FIG. 1, the detection area γ is oriented so as to intersect with the discharge water B4, and the intersection angle (intersection angle in a vertical plane) between the direction d and the discharge water B4 is: Even if the trajectory of the discharge water B4 is close to vertical at the time of the minimum flow rate, the trajectory is adjusted so as not to be larger than 70 degrees (preferably 65 degrees).
[0028]
Referring to FIG. 2 again, the arithmetic unit S2 is configured by a microcomputer having an A / D conversion function, and the sampling frequency of the A / D conversion can be changed by a program. The analog voltage input from the amplifying unit S6 is chronologically stored in the storage unit as digital data in synchronization with the light emitting cycle of the light emitting unit S4, and this data is statistically processed. A valve opening or valve closing signal is output to the output section S3 based on the result.
[0029]
The output unit S3 converts the signal from the calculation unit S2 into valve drive power and outputs the same to the solenoid valve B5.
[0030]
Prior to the description of the statistical calculation, a basic pattern of the reflected light level under each condition will be described with reference to FIG.
[0031]
In the standby state, that is, when there is no water spouting from the spout B2 and no hand is present below the spout 50, the reflected light from the surface of the bowl B1 enters the light receiving unit S5 as shown in FIG. The reflected light level is constant and its fluctuation is extremely small.
[0032]
In the state where the hand is being washed in the water B4 discharged from the spout B2, as shown in FIG. 3B, the reflected light level is large and fluctuates due to the movement of the hand and the splash of water.
[0033]
When there is no hand below the spout B2 and only the discharge water B4, the reflected light from the surface of the bowl B1 is absorbed by the discharge water B4, and the reflected light level decreases as shown in FIG. Due to the movement of the discharge water B4, the fluctuation of the reflected light level takes an intermediate value between the non-use time and the hand wash time.
[0034]
From the pattern of the reflected light level, it is possible to determine the presence or absence of the hand below the spout B2.
[0035]
However, since the above-mentioned pattern is a principle, and there is an accidental level fluctuation due to disturbance, noise, or the like, a comparison between a mere reflected light level and a set value, and a differentiation of the reflected light level fluctuation and a set value are not performed. As described in the comparison of the above, it is not always accurate to judge by capturing the local features of the pattern, and the fact is that the malfunction rate is high.
[0036]
Therefore, in this embodiment, the reflected light levels input in time series are statistically processed, and the reflected light levels are detected by comparing the moving average value of the levels with the set value and comparing the variance value with the set value. Determine the presence or absence of a human body within the range. That is, by recognizing the entire pattern of the reflected light level, the influence of the accidental level fluctuation is eliminated. In addition, by using the average value in the standby state and updating the set value for comparison with the average value, the change in the reflectance of the inner bottom surface of the bowl B1 and the deterioration of the sensor are corrected. As a result, the detection of the human body is performed accurately.
[0037]
That is, in the standby state, light is emitted from the light projecting unit S4 of the optical sensor S1 at a frequency of 2 Hz, the output voltage from the light projecting unit S5 is sampled at a cycle synchronized with the above, A / D converted, and this is stored in the memory. In time series. Then, among these stored data, the average value of the latest eight data and the variance thereof are calculated.
[0038]
When the dispersion value is 1 or less, the duration is counted, and when the counter reaches 30 seconds, the average value is stored in a memory as a reference level (a level of light reflected from the surface of the bowl B1). Thereafter, when the variance value is 1 or less every time light is projected, the reference level stored in the memory is updated each time. The above counting is performed up to 30 seconds, and the counting is not proceeded any longer. If the variance value becomes 2 or more during the counting, the counter is reset.
[0039]
As described above, in the standby state, by updating the data of the reflection level from the surface of the bowl B1 every time light is projected, it is possible to correct the change in the reflectance of the surface of the bowl B1 and the deterioration of the optical sensor S1.
[0040]
Then, when the difference between the average value and the reference level becomes 4 or more during the standby state, the frequency of light emission and sampling is changed to 16 Hz, and preparations are made to increase the responsiveness of hand detection. In addition, if the projection of 16 Hz is repeated 16 times without satisfying the first condition described later, the frequency returns to the original frequency of 2 Hz. However, if the difference between the reference level and the average value becomes 4 or more before reaching the above 16 times, the counting of 16 times is restarted from that point.
[0041]
The first condition refers to a case where at least one of the following conditions (1) and (2) is satisfied.
[0042]
(1) Average value ≥ reference level + 8
{Circle around (2)} The variance ≧ 6 continues four times or more.
[0043]
When the first condition is satisfied during the above-described 16 Hz preparation state, it is determined that a hand is present below the spout B2, and the valve V is opened to discharge water from the spout B2.
[0044]
In this way, when the following second condition is satisfied during the water discharge from the spout B2, the valve V is closed to stop the water. When the light emission at 16 Hz is repeated 48 times after stopping the water (3 seconds have elapsed), the light emission and the sampling frequency return to 2 Hz.
[0045]
The second condition refers to a case where both of the following conditions (1) and (2) are satisfied.
[0046]
(1) Average value ≤ reference level + 4
{Circle around (2)} The dispersion value ≦ 3 continues four times or more.
[0047]
After the water stoppage, before one of the 16 Hz light emission and the number of samplings reaches 48, if one of the following third conditions is satisfied, the water discharge is restarted.
[0048]
The third condition refers to a case where at least one of the following conditions (1) and (2) is satisfied.
[0049]
(1) Average value ≥ reference level + 8
{Circle around (2)} The variance ≧ 6 continues 10 times or more.
[0050]
As described above, by making the third condition for re-water discharge immediately after stopping water stricter than the first condition, malfunction due to turbulence immediately after stopping water can be prevented.
[0051]
In this embodiment, in order to save power consumption, the frequency of light emission and sampling in the standby state is set to a low speed of 2 Hz. However, when power saving is not required, the frequency in the standby state is also set to the ready state. The response can be made faster and the program can be simplified as in the case of 16 Hz.
[0052]
Conversely, when further power saving is desired, the frequency may be set to 2 Hz not only during standby but also during spouting. However, in the case of uniformly 2 Hz, only when the above-described conditions of water discharge start, stop, and restart are satisfied, respectively, in order to quickly confirm that the conditions are satisfied and to improve the responsiveness of water discharge start and stop, It is desirable to temporarily increase the frequency (for example, a period of 7 ms).
[0053]
Further, in the present embodiment, the average value and the variance value are used together to determine the presence or absence of a hand, but a standard deviation may be used instead of the variance value. Alternatively, the determination may be made using only the latest reflected light level and the reference level (average value during standby) without using the dispersion value or the standard deviation. Since the variance or standard deviation is a statistical value that well represents the continuity of the state, if these are not used, additional information for confirming the continuity of the state when a change in the state of the presence or absence of a hand is detected It is desirable to perform the operation. For example, when it is detected that a hand is out during standby, or when it is detected that a hand has been removed during spouting, the additional data sampling is performed several times (for example, twice). Then, it should be checked whether or not the detected state continues, and the water discharge start or stop should be executed only when it is confirmed that the state continues. In this case, it is desirable that the additional sampling be performed at a sufficiently short cycle (for example, 7 msec) in order to increase the responsiveness of the start or stop of water discharge. Furthermore, when the variance value and the standard deviation are not used, when determining the reference level, the difference between the latest data and the average value must be within a certain small range in order to confirm that the standby state is stable. You should check that it is within.
[0054]
Or, malfunction occurs due to the start and stop of water discharge based on both the result of comparison between the latest level and the reference level (average value not including the latest value) and the result of comparison between the absolute value of the latest level and a predetermined threshold. Can also be reduced. In this case, as will be described later with reference to FIG. 8, in order to interrupt the repeated operation of the water discharge and stop water when an incorrect value is stored in the reference level, the water discharge counter is filled before the water discharge counter satisfies a predetermined number. After that, it is desirable to change the threshold so as to increase.
[0055]
FIG. 4 shows a main routine of the above-described processing. First, when the power is turned on in step (S50), the main routine including steps (S51) to (S55) is entered. The operation of the automatic faucet is performed by turning around this main routine.
[0056]
In step (S51), the frequency that goes around the main routine is determined based on the contents described in the following FIG. In step (S52), the time is adjusted so that the main routine runs at a time corresponding to the frequency of 16 Hz or 2 Hz determined in step (S51). However, the cycle is 62.5 msec at 16 Hz and 500 msec at 2 Hz, and the processing time of steps (S51) and (S53) to (S55) is about several msec. Used in S52).
[0057]
In step (S53), light is emitted from the sensor unit to store the data, and in step (S54), the data is statistically calculated (described above).
[0058]
Step (S55) is a subroutine for controlling water discharge and water stoppage based on the statistical data.
[0059]
FIG. 5 shows the details of the frequency switching subroutine (S5). First, it is checked whether water is discharged (S58) or within 3 seconds after stopping the water (S59). Go to and set the frequency to 16 Hz.
[0060]
If none of the conditions of steps (S58) and (S59) is satisfied, the process proceeds to step (S60).
[0061]
In step (S60), if the average value is equal to or more than the reference level (the level of light reflected from the surface of the bowl B1) +4, the flow proceeds to step (S61); otherwise, the flow proceeds to step (S63). In step (S61), the frequency at which the main loop rotates is set to 16 Hz, and in step (S62), the counter that counts the number of rotations at 16 Hz is reset, and the subroutine is exited from step (S67).
[0062]
In step (S63), the average value is close to the reference level, and it is first checked whether the frequency is 16 Hz. If it is not 16 Hz, it is 2 Hz, but 2 Hz is checked again in step (S66), and the subroutine is exited from step (S67).
[0063]
If it is 16 Hz in step (S63), it is checked in step (S64) whether the 16 Hz counter is 16 or more. If it is less than 16, the 16 Hz counter is advanced by one in step (S65) and the process proceeds to step (S67).
[0064]
That is, the number of times of projecting at 16 Hz while the average value of the signal is less than the reference level +4 is counted every time the main loop is turned.
[0065]
When the 16 Hz counter reaches 16 in step (S64), the process proceeds to step (S66), sets the frequency to 2 Hz, and exits the subroutine from step (S67).
[0066]
As shown in FIG. 6, the water discharge control subroutine (S55) has a function of updating the reference level. If the variance value is equal to or less than 1 (S70Y), the timer is activated and 30 seconds elapse (S71Y). , The reference level is updated (S72), and the process proceeds to step (S80) described later. If the timer is shorter than 30 seconds (S71N), the process proceeds to step (S80). If the variance value is greater than 1 (S70N), the timer is reset (S73), and the process proceeds to step (S80).
[0067]
In step (S80), the state of water spouting from spout B2 is determined, and if water spouting is performed (S80Y) and variance ≤3 (S81Y), the first counter is incremented (S82) and the first counter is incremented (S82). If the counter becomes 4 (S83Y) and if the average value ≦ the reference level + 4 (S84Y), the valve is output to the electromagnetic service B5 (S85), the first counter is reset (S86), and the frequency switching subroutine is performed. (S99). If the variance value> 3 (S81N), the first counter is reset in step (S98), or if the first counter value is 4 or less (S83N), or if the average value> reference level + 4 (S84n). ), And proceeds to step (S99).
[0068]
In the case of water discharge (S80N), measurement of the water stoppage time is started (S87). If the dispersion value ≥6 (S88Y), the second counter is incremented (S89), and the water stoppage time is 3 seconds. That is all (S90Y), and when the second counter becomes 4 (S91Y), the solenoid valve B5 is output to open (S92), the second counter is reset (S93), and the measurement of the water stop time is stopped (S91). S94). If the value of the second counter is 4 or less (S91N), the process proceeds to step (S96). If the variance value <6 (S88N), the second counter is reset (S95). If the average value ≧ the reference level + 8 (S96Y), the process proceeds to step (S92). If the average value <the reference level + 8 (S96N), the process returns to the main routine. Furthermore, if the water stoppage time is less than 3 seconds (S90N) and the second counter is 10 or more (S97Y), the process proceeds to step (S92), and if the second counter is less than 10 (S97N). , To step (S96).
[0069]
The count value A in step (S82) for counting that the variance value is equal to or greater than the predetermined value and the count value B in step (S89) are for checking whether the variance value continues for a certain time. By changing the reference value for the value, the severity of the condition can be adjusted.
[0070]
FIG. 7 shows an example of the reflected light level d, its average value and its variance.
[0071]
In the figure, d is a reflected light level, e is an average value, and f is a variance value.
[0072]
For example, at time T1, the first condition described above is satisfied with respect to the average value or the variance value, and the water discharge is started. Even if the average value falls below the threshold value in step (S84) in FIG. 6 at T2, the variance value remains large and the water does not stop.
[0073]
Conversely, even if the variance value becomes small at T3, the water stop condition is not satisfied with the average value.
[0074]
At T4, when the reflection level of the signal decreases and there is no change, both the average value and the dispersion value decrease, and the water stopping condition is satisfied.
[0075]
Also, after the water stops, a certain time delay occurs due to the characteristics of the solenoid valve until the spout B2 actually stops discharging water, and when the water stops, the flow of the discharge water B4 is disturbed, and the water is largely reflected by the irregular reflection. Light may be generated (FIG. 7, T5 timing).
[0076]
Since such reflected light is instantaneous, the dispersion temporarily increases, but immediately decreases. If it is within 3 seconds after water stoppage in step (S90) in FIG. 6, water is not re-discharged unless the number of times “dispersion value ≧ 6” is continued at least 10 times in step (S97). Water is not accidentally spouted by turbulence.
[0077]
According to the above control, the following effects can be obtained.
[0078]
By using the average value of the reflected light level, the influence of a single noise can be reduced.
[0079]
By using the dispersion of the reflected light level, the hand-washing operation can be reliably detected.
[0080]
In other words, the derivative responds strongly to spike-like noise and does not easily respond to slow movements such as handwashing, whereas the variance or standard deviation is a value related to the variation, so that the personality is affected by speed like handwashing. Even a motion having a difference is hardly affected by the difference in the operation speed. Further, the variance or standard deviation is a value that is stably output as long as the movement is continued, and thus is optimal for detecting a movement that continues for a certain time such as a hand-washing operation.
[0081]
Furthermore, the work of storing a predetermined number of data and dividing the change into several patterns becomes very complicated, but the average and variance can be obtained by a simple calculation, so that the load when developing and evaluating a product is small.
[0082]
Also, in order to determine the human body based on the pattern of change, conditional branching such as case classification and combination is used.However, since variance quantifies the change, the judgment is made by comparing it with numerical values. Can easily be created and changed.
[0083]
Further, by determining and updating a reference value (reflection level of the bowl B1) based on the average value and the variance value, it is possible to remove the influence of the reflectance of the bowl B1 over time and the deterioration of the sensor.
[0084]
As described above, by performing statistical processing of the reflected light level, it is possible to quantitatively evaluate complicated signal patterns and disturbances, and it is possible to accurately detect the presence or absence of a human body and prevent malfunction. can do.
[0085]
The above is the control operation in a normal use condition. As shown in FIG. 6, by changing the condition of water discharge immediately after stopping the water and at other times, the influence of the water discharge on the sensor operation can be eliminated.
[0086]
However, in the case of the above control, since water discharge / stop water is controlled based on the reflection level from the bowl B1 when water is not discharged, storing an incorrect value in the reference level may cause a malfunction.
[0087]
For example, if the light emitting / receiving surface of the sensor unit is dirty and the signal of the sensor is attenuated, or if a rag or a towel with a small reflection of light is placed on the bowl B1 surface of the basin, the reflection level is lower than the original reflection level of the bowl B1. It is stored based on a small level. From this state, if the sensor surface is cleaned or the rag is removed, this will increase the average value of the reflected light. When the average value is sufficiently increased and the water discharge condition is satisfied (step S96Y in FIG. 6), water discharge occurs even though the hand is not extended.
[0088]
Generally, automatic faucet is subjected to a safety treatment to prevent water from being discharged forever. For example, the water is stopped for a maximum of one minute regardless of the sensor signal. Even if an erroneous value is stored in the reference level and water is erroneously discharged, the water can be stopped for the time limit and then the normal value can be returned by storing the correct value in the reference level.
[0089]
However, there are special cases that cannot be dealt with by such a process of limiting the water discharge time. For example, when the rag is removed from the bowl B1 as described above, the level of the reflected light from the bowl B1 rises and water is erroneously discharged. Subsequently, the reflected light from the bowl B1 is absorbed by the discharge water B4, and the average value of the reflected light level is It drops again. When the average value decreases until the condition for stopping water is satisfied, the water stops, and subsequently the reflected light level rises again to the reflection level of the bowl B1, so that water is discharged again. Water discharge / water stoppage is repeated endlessly.
[0090]
FIG. 8 shows a water discharge control subroutine that takes measures against this repetitive operation. This subroutine is obtained by adding this countermeasure processing to the routine shown in FIG. 6, and the same parts as those in the routine of FIG. 6 are denoted by the same reference numerals.
[0091]
In the control of FIG. 8, a "water discharge counter" indicating the number of times of water discharge to be performed is added. The “water discharge counter” is reset after step (S72). That is, if the state where the variance is 1 or less (S70Y) continues for 30 seconds or more (S71Y), the average value is stored as the reference level (S72), and then the step (S70Y) repeats the above-described water discharge / water stoppage. Since the state is not performed, the initial value “1” is set in the water discharge counter.
[0092]
Thereafter, when the water discharge condition is satisfied, water discharge is performed in step (S92), and the water discharge counter is incremented by +1 in step (S101). Thereafter, the steps after step (S93) are the same as the routine of FIG.
[0093]
First, if it is not water discharge (S80Y), it is checked whether the water discharge condition is satisfied. If the water discharge condition by dispersion is not satisfied (S88N) (S91N) (S97N), it is checked whether the water discharge counter is 10 or less before checking whether the water discharge condition by average value is satisfied (S96) ( S103). In the case of 10 or less (S103Y), the water discharge condition of the average value is checked as in the case of FIG. 6 (S96). When it is larger than 10 (S103N), the check of the water discharge based on the average value is not performed.
[0094]
As a result, even if the above-described malfunction of repeating water discharge / water stoppage due to an error in the average value occurs, when the number of times of water discharge / water stoppage reaches 10 times, water discharge under the condition of the average value is prohibited, This malfunction is stopped.
[0095]
FIG. 9 shows an example of a signal at the time of repeated water discharge / water stoppage. Until the time T10 in FIG. 9, the reflection of the bowl B1 is blocked by an obstacle such as a rag, and the reference level lower than the actual level is stored. When the obstacle is removed at the time T10, the reflection level of the signal returns to the reflection level of the bowl B1, but since this is greater than the reference level stored by the time T10 by 8 or more, the solenoid valve is opened (FIG. 7). Step (S96Y)). Actually, there is a delay from the opening operation of the solenoid valve until the water is discharged from the spout B2. When the spout absorbs the signal light at time T11, the reflection level decreases, and the condition for continuing the spout (S84N) cannot be satisfied, and the solenoid valve is closed.
[0096]
There is also a delay from when the solenoid valve closes until no water comes out of the spout. When the signal returns to the reflection level from the bowl B1 at time T12, the average value increases and water is discharged again.
[0097]
In this way, water discharge / water stoppage is repeated. At time T13 when the tenth water discharge ends, the reflection of the signal returns to the reflection from the bowl B1 with the water discharge counter being eleven times. Here, although the average value increases, water discharge under the condition of the average value is prohibited (S103N), so that water discharge does not occur, and as a result, the malfunction of repeating water discharge / water stoppage ends.
[0098]
When the water discharge ends, the variance becomes small (S70Y), and after 30 seconds (S71Y), the average value of the correct reference level is stored as the reference level. At the same time, the water discharge counter is reset to 1 in step (S101). At this time, a malfunction does not occur again because the correct reference level is stored. In the case where water is discharged / stopped repeatedly without actually malfunctioning, the water is discharged only based on the conditions of dispersion from the eleventh time onward. Therefore, water discharge is performed based on both the average value and the dispersion value. Although the quickness of the response is inferior to the case where water is discharged, the water is reliably discharged, so that there is no particular problem in terms of usability. Note that the number of times of stopping the erroneous repetition is one example, and an appropriate numerical value may be set according to the product.
[0099]
In this embodiment, until the water discharge counter reaches a predetermined number of times, water is discharged if either one of the condition based on the average value or the condition based on the variance value is satisfied, and after the water discharge counter reaches the predetermined number of times, the variance value is used. Water is discharged when only the conditions are met. However, after the water discharge counter satisfies the predetermined number of times, the same effect can be obtained if the water discharge start condition is strict. As a way to make the conditions stricter, for example, changing the condition so that water is discharged when both the condition based on the average value and the condition based on the variance value are satisfied, or changing the value to be compared with the average value or the variance value to a value that makes it difficult to discharge water It can be changed.
[0100]
It is to be noted that countermeasures against malfunctioning water discharge due to dispersion have already been taken in step (S97N) of FIG.
[0101]
As described above, various measures relating to the dispersion and average value of the reflected light level are combined, and various measures are made with simple measures such as prohibiting any of the conditions, thereby making it possible to take measures against malfunctions such as malfunctions. Flexible.
[0102]
The present invention is not limited to optical sensors, and can be widely applied to non-contact type active sensors such as ultrasonic sensors.
[0103]
【The invention's effect】
As described above, according to the present invention, in a human body detection device using a reflection-type non-contact active sensor used in an automatic faucet or the like, a local characteristic of a chronological pattern of reflection levels is accidentally generated. Even if the target level fluctuation is superimposed, only the human body can be detected with high accuracy.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a use state of an embodiment of an automatic faucet according to the present invention.
FIG. 2 is an explanatory diagram illustrating a configuration of an optical sensor.
FIG. 3 is a graph showing a relationship between a pattern of a level of reflected light incident on a light receiving unit, an electromagnetic valve opening / closing, and light emitting / sampling frequency.
FIG. 4 is a flowchart of a main routine for processing a signal from an optical sensor.
FIG. 5 is a flowchart of a frequency switching subroutine.
FIG. 6 is a flowchart of a water discharge control subroutine.
FIG. 7 is a graph showing an example of a reflected light level, an average value, and a variance value.
FIG. 8 is a flowchart illustrating a water discharge control subroutine to which a countermeasure process for repeated water discharge / water stoppage is added.
FIG. 9 is a graph showing a reflection level and an average value when water discharge / water stoppage is repeated.
[Explanation of symbols]
A automatic faucet
S human body detection device
S1 Optical sensor
S2 operation unit

Claims (7)

In a human body detection device that detects the presence or absence of a human body by a reflective non-contact active sensor,
The data of the reflection signal level from the active sensor is periodically sampled, and a statistic including an average value and a variance value or an average value and a standard deviation value is obtained from a plurality of continuously sampled data including the latest data. Statistical calculation means for calculating a value,
Under the condition that the variance value or the standard deviation value is smaller than a certain value, a reference level determining unit that determines the average value as a reference level representing a state without a human body,
Determining means for determining the presence or absence of a human body based on the statistical value and the reference level,
A human body detection device comprising: The device of claim 1,
A human body detection apparatus, further comprising a cycle control unit that detects a significant change in the reflected signal level from the statistical value when the determination result of the determination unit indicates that there is no human body, and that increases the sampling cycle. The device of claim 1,
The determination means changes the determination result to the presence of a human body when the statistic value satisfies a predetermined first condition in a state where the determination result is that there is no human body for a longer time than a predetermined time, and the determination result is that a human body is present. In the state, when the statistic satisfies the predetermined second condition, the determination result is changed to no human body, and when the determination result is that there is no human body for a time shorter than the predetermined time, the statistic is the predetermined third value. When the condition is met, change the judgment result to the presence of a human body,
A human body detection device, wherein the third condition is more difficult to satisfy than the first condition. In a human body detection device that detects the presence or absence of a human body by a reflective non-contact active sensor,
Statistical calculation means for periodically sampling data of the reflection signal level from the active sensor and calculating at least one type of statistical value from a plurality of continuously sampled data including the latest data;
Determining means for determining the presence or absence of a human body based on the statistical value,
A counter that counts the number of times the judgment change from no human body to presence is continuously repeated at intervals shorter than a predetermined time,
When the value of the counter exceeds a predetermined value, prohibiting means for prohibiting repetition of the continuous determination change,
A human body detection device comprising: In a human body detection device that detects the presence or absence of a human body by a reflective non-contact active sensor,
  The data of the reflection signal level from the active sensor is periodically sampled, and from a plurality of continuously sampled data including the latest data, at least one of an average value, a variance value, and a standard deviation value is obtained. Statistical calculation means for calculating a statistical value;
  A determination means for determining the presence or absence of a human body based on the statistical value, wherein the determination result is determined when the statistical value satisfies a predetermined first condition in a state where the determination result is that the human body is not present for a time longer than a predetermined time. When the statistic value satisfies the second predetermined condition in a state in which the human body is present and the determination result is a human body, the determination result is changed to no human body, and the human body is changed for a shorter time than the predetermined time. Determining means for changing the determination result to the presence of a human body when the statistic value satisfies a predetermined third condition in a state of no presence;
  A counter that counts the number of times the judgment change from no human body to presence is continuously repeated at intervals shorter than a predetermined time,
  Condition changing means for changing the first condition and the third condition to more strict conditions when the value of the counter exceeds a predetermined value;
  A human body detection device comprising: The device according to claim 5,
  The statistical calculation means calculates a statistical value including the average value and the variance value,
  Until the value of the counter exceeds a predetermined value, the first condition is a condition that one of the average value or the variance value satisfies each predetermined condition,
  When the value of the counter exceeds a predetermined value, the first condition is changed to a condition that at least the variance value satisfies a predetermined condition. The device according to claim 5,
  Under the condition that the variance value or the standard deviation value is smaller than a certain value, a reference level determining unit that determines the average value as a reference level representing a state without a human body,
  The statistical operation means calculates the average value and the variance value, or a statistical value including the average value and the standard deviation value,
  Until the value of the counter exceeds a predetermined value, the first condition is that the difference between the reference level and the average value is equal to or greater than a first predetermined value and the absolute value of the latest data is equal to or greater than a second predetermined value. Is the condition
  When the value of the counter exceeds a predetermined value, the second predetermined value is changed to a larger value.

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