JP4122562B2 - Vehicle occupant detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an occupant detection device for a vehicle that detects the presence and position of an occupant in a vehicle interior using an infrared area sensor.
[0002]
[Prior art]
Conventionally, it has been proposed to detect a person seated in a passenger compartment and cause a predetermined vehicle device to act only on the person.
[0003]
[Problems to be solved by the invention]
As this type of proposal, there is one disclosed in Japanese Patent Laid-Open No. 7-55573. This uses an infrared sensor to detect whether a person is seated in each seat of an automobile and increases the safety by deploying an airbag only on the seat where the person is seated. It is intended to reduce the power consumption of the vehicle by operating the air conditioning system only on the seat where the vehicle is seated.
[0004]
However, since the effect of the airbag varies depending on the seating position of the person or the physique of the person, there is a demand for finely controlling the deployment speed and the amount of the injected gas of the airbag. Further, in the air conditioning system, there is a demand to detect indoor temperature distribution and human skin temperature, and to finely control the orientation and temperature control of the blowout air. The problem that the request could not be solved remained.
[0005]
Furthermore, although a configuration has been proposed in which an intruder into a vehicle is detected by an infrared sensor, there is a disadvantage that there are many malfunctions when the presence or absence of an intruder is determined only by a temperature change by the infrared sensor.
[0006]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle occupant detection device that can reliably detect the presence and position of an occupant in a configuration for detecting an occupant in a vehicle interior. is there.
[0007]
[Means for Solving the Problems]
According to the invention of claim 1, since the infrared area sensor detects the temperature distribution of the predetermined detection target region set in the vehicle interior, the thermal image data creating means is based on the temperature distribution detected by the infrared area sensor. Create thermal image data.
[0008]
By the way, when there is no temperature difference between the passenger's temperature and the background of the door or seat in the passenger compartment, the presence / absence and position of the passenger can be determined based on the thermal image data created by the thermal image data creation means. Disappear.
[0009]
Now, when the occupant gets into the vehicle, the door is opened, so the detection area of the infrared area sensor is attached so that the temperature distribution outside the vehicle can be acquired when the vehicle door is opened. If you are an infrared area sensor can acquire the outside environment temperature.
[0010]
Therefore, the occupant determination means acquires the thermal image data created by the thermal image data creation means immediately after the occupant performs the boarding or getting-off operation by the boarding / alighting detection means, and when the door is opened, through the opened door The thermal image data created by the thermal image data creation means is obtained from the passenger's background and the thermal image data obtained at the previous detection timing is compared with the thermal image data obtained at the previous detection timing. Judgment can be made reliably.
[0012]
According to the invention of claim 2 , since the boarding / alighting detection means determines that the boarding or the boarding operation has been executed when the occupant releases the door lock, the occupant detection means has a large temperature before and after the timing when the door is opened. By tracking the change, it is possible to reliably determine the occupant.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS.
In FIG. 2 showing the vehicle interior, an infrared area sensor unit is arranged on the ceiling of the vehicle. In FIG. 2, the infrared area sensor units 1 and 2 are attached to positions corresponding to the front seat and the rear seat on the roof in the vehicle interior.
[0025]
FIG. 1 schematically shows the overall configuration. In FIG. 1, a lens 4 is disposed in front of the infrared area sensor 3, and a thermal image of a detection target region is formed on the infrared area sensor 3 by the lens 4. This lens 4 is an infrared condensing lens made of high-density polyethylene, chalcogen glass, BaF2, ZnS or the like, and has a spherical, aspherical, or Fresnel shape.
[0026]
The infrared area sensor 3 has a shape in which the heat detection elements 5 are gathered in a two-dimensional matrix, for example, 15 × 10, and the infrared rays emitted from the periphery of the door are collected by the lens 4 to collect the heat detection elements. 5 is imaged as a thermal image. In this case, the lens 4 is designed so that a range of 750 × 500 mm can be condensed on the entire heat detection element 5 at a position separated by, for example, 500 mm. Therefore, if the number of heat detection elements 5 of the infrared area sensor 3 is 15 × 10, the range (detection resolution) that can be detected by one heat detection element 5 is 50 mm square.
In the infrared area sensor 3, a signal generation circuit 6 and a selection circuit 7 are installed around the heat detection element 5.
[0027]
As shown in FIG. 3, the heat detecting element 5 alone forms the SiO2 thin film 5a, the metal thin film resistor 5b, and the absorption film 5c on the Si substrate 3a, and then removes the back side of the metal thin film resistor 5b by etching. As a result, the metal thin film resistor 5b is formed in a heat insulating structure located with an air gap from the Si substrate 3a.
[0028]
FIG. 4 schematically shows the electrical configuration of the infrared area sensor 3. In FIG. 4, the heat detection element 5 of the infrared area sensor 3 is selected one by one through the FET by the X ring counter 7a and the Y ring counter 7b constituting the selection circuit 7, and is selected. The temperature distribution in the detection target region of the infrared area sensor 3 is detected by sequentially taking the signal from the thermal detection element 5 into the signal detection / processing circuit 8 (corresponding to the thermal image data creation means) shown in FIG. Can do.
[0029]
That is, in FIG. 1, the signal detection / processing circuit 8 includes a signal amplifier 9, a signal processing circuit 10, and a data transmission circuit 11, and a thermal image based on a temperature distribution by the infrared area sensor 3 in the signal processing circuit 8. Create data.
[0030]
The various system control circuits 12 are described later based on the thermal image data from the signal detection / processing circuit 8, the door lock switch 13 (corresponding to the getting on / off detection means), and the detection result of the weight sensor 14 provided on the seat. A predetermined vehicle system is controlled.
[0031]
Next, the operation of the above configuration will be described.
In the heat detection element 5 of the infrared area sensor 3, the incident infrared ray is absorbed by the absorption film 5c to be converted into heat, and the temperature of the metal thin film resistor portion 5b rises due to the heat and the resistance value changes. Therefore, the temperature distribution of the detection target region can be detected by sequentially outputting the sensor signal from the heat detection element 5 to the signal detection / processing circuit 8.
[0032]
The signal detection / processing circuit 8 can create thermal image data of the detection target region by taking in the signals from all the thermal detection elements 5. That is, the thermal image data is created by processing the temperature distribution data detected by the infrared area sensor 3 by the signal processing circuit 10. The thermal image data is transmitted to various system control circuits 12 by the data transmission circuit 11 and used for detecting the position of a person located in the detection target region.
[0033]
As an example of such a person detection method, the temperature inside the vehicle is monitored at regular intervals, an intruder or a moving object is determined by detecting a sudden change in temperature, and a person is determined from the temperature distribution at that time. It is supposed to be. At this time, as a detection cycle of the infrared area sensor 3, as shown in FIG. 5, the infrared area sensor 3 is operated at a cycle of 80 msec.
[0034]
Here, FIG. 6 shows a flowchart of basic operations for determining the presence and position of an occupant by the infrared area sensor 3. In FIG. 6, first, it is determined whether or not the door lock is released (S101). When the door is locked with the key OFF, the system is released.
[0035]
When the door lock is released for the passenger to get on (S101: YES), the temperature data of each seat is acquired to improve the determination accuracy (S102), and the temperature comparison with the previous acquired data (output change / After calculating (unit time) (S103), by extracting an edge from the background (S104), it is possible to grasp the transition of the temperature change of each seat and each heat detection element 5 and determine whether it is a passenger or noise ( S106).
[0036]
In this case, it is determined from the previous acquired data and the degree of temperature change that the vehicle is a moving body such as an occupant or an intruder as follows.
First, since it is necessary to determine whether the temperature change is caused by a moving body as described above or due to an environment such as a temperature change caused by direct sunlight irradiation of sunlight, the temperature change amount / time as shown in FIG. Judging from. That is, as shown in FIG. 7, the temperature change due to moving objects (for example, a temperature difference from the background of 0.5 ° C. and a moving speed of 0.25 m / s) is large, but the temperature change due to the environment such as solar radiation is small. Therefore, it can be determined based on the difference. For example, when data is acquired in a detection cycle (80 msec) as shown in FIG. 5, there is a heat detection element 5 in which the temperature change from the previous acquired data is about 0.2 ° C. or more from FIG. Sometimes, the position of the heat detecting element 5 having such a temperature change can be determined as the moving body position.
[0037]
Specifically, as shown in FIG. 8, when attention is paid to a detection target region (a range indicated by an arrow A in the drawing) of a specific heat detection element 5, when a person gets into the vehicle, the vehicle interior temperature ( The temperature of the detection target area, which was 25 ° C., increases to the human temperature (30 ° C.), and the detection temperature changes by 5 ° C. during 80 msec. In other words, under the condition that the person moves, such a temperature change always occurs in the heat detection element 5 corresponding to the movement area of the person, and the presence of the person can be detected.
[0038]
Note that the detection of the occupant as described above can improve the reliability of the determination by simultaneously using the signal from the weight sensor 14 provided on the seat and the like together with the signal from the infrared area sensor 3 (S105). ). That is, although the detection accuracy of the weight sensor 14 is high, a load is often placed on the seat. This improves the detection accuracy.
[0039]
By the way, when the difference between the temperature of the occupant moving (invading) into the vehicle and the temperature of the seat or the like acquired at that time is small, the determination based on the temperature distribution by the infrared area sensor 3 may be difficult. That is, since the temperature change is small in data acquisition every 80 msec, it is difficult to distinguish from the occurrence due to the environment depending on the capability of the signal detection / processing circuit 8.
[0040]
Therefore, not only the data processing method as shown in FIG. 9, that is, not only the data comparison process with the previous acquired data (ascertaining the degree of temperature change) but also the data comparison process with the acquired data several times before are performed simultaneously. Further, it becomes possible to widen the condition range in which the determination can be made.
[0041]
Therefore, even when the occupant slowly gets on, a large temperature change can be obtained, so that the occupant can be reliably detected while distinguishing from the temperature change due to the environment.
[0042]
Specifically, when attention is paid to one heat detection element 5, the heat detection element acquires an average temperature of an area of 50 mm square at a distance of 500 mm. Here, when an object having a different temperature (ΔT) enters the area, the average temperature of the area becomes equal to the area ratio occupied by the entering object. In this case, the occupied area ratio depends on the speed of the intruder, and if it moves slowly, the temperature change at the sensor position becomes slow.
[0043]
At this time, as shown in FIG. 10, for example, if the threshold value for determining whether the temperature is changed by an occupant (intruder) or the temperature is 0.3 ° C., the determination is made after 80 msec. In this case, for example, if the temperature difference (ΔT) between the occupant and the background is 0.5 ° C., an object that moves at an intrusion speed of 0.41 m / s or more reaches 0.3 ° C. after 80 msec. It cannot be detected at intrusion speeds lower than that.
[0044]
Therefore, as described above, the speed range that can be determined by extending the determination time to 160 msec or 240 msec is expanded, and the condition area that can be detected can be expanded. In this case, it is necessary to make a comparison within a time range in which the change due to the environment does not exceed the threshold value.
[0045]
By the way, although the above determination is possible when the occupant is moving, in the state where the occupant is seated and always stationary, the temperature change is eliminated, so that it is difficult to determine the position of the occupant.
[0046]
Therefore, the current state of the occupant was grasped by tracking and recording the position after the occupant moved. At the same time, the presence / absence of a passenger is determined based on the gap in the temperature difference in the background. That is, as shown in FIG. 11, when the occupant's temperature differs from the background seat or the like, the presence / absence of the occupant is determined by extracting the temperature difference (see FIG. 12). Further, if the air conditioning in the vehicle is almost completed, the temperature difference between the passenger and the background becomes large, and this determination becomes easier. In this case, when a baggage is detected, the temperature difference from the background disappears after a certain amount of time has elapsed, so that it is possible to distinguish the passenger from the passenger.
However, even if the above two determinations are used, this determination cannot be used when the passenger, the background sheet, the glass, and the like are all smaller than the limit temperature difference.
[0047]
However, in the present embodiment, the above-described two processes are performed immediately after unlocking the vehicle, thereby making it easier for the passenger to determine.
That is, when the infrared area sensor unit 1 is mounted at the position shown in FIG. 2, the infrared area sensor 3 acquires the temperature information of the area including the vehicle door 15 as shown in FIG. That is, when the door 15 is opened, as shown in FIG. 14, external objects such as the ground, trees, and sky existing outside the vehicle on the other side of the door 15 are present in a part of the background.
[0048]
In this case, when the door lock is released, but the passenger does not get in, the door does not open and the temperature change is only caused by the environment. For example, the environmental temperature gradually changes or changes due to the direct sunlight of the sun can be considered, and as described above, it can be distinguished from the moving object (occupant).
[0049]
In addition, when the occupant gets in, the comparison temperature data for acquiring the temperature change by always opening the door 15 includes the ground outside the vehicle, the atmosphere, the sky, and the like. Since it is not expected that all of them will be at the same temperature, even if the seat 16 in the vehicle is at the same temperature as the occupant who gets in, the temperature of the occupant is obtained by the temperature difference from the outside of the vehicle (See FIGS. 15 and 16, the range indicated by the arrow B in the figure is the detection target region of one heat detection element 5).
[0050]
Further, since the movement of the air in the vehicle occurs due to the opening of the door 15, the possibility that the seat 16 and the occupant in the vehicle will remain at a uniform temperature is further reduced, and the determination of the occupant becomes easier.
[0051]
Now, returning to FIG. 6, when the passenger is determined as described above, the temperature distribution data of the detection target region is created based on the output from each heat detection element 5 (S107), and the temperature distribution data is included in the temperature distribution data. Based on this, the position of the face is determined as follows.
[0052]
First, an existing temperature range of each occupant's face is acquired (S108). In other words, in the present embodiment, the infrared area sensor 3 acquires the temperature distribution of an area of about 500 × 750 mm 500 mm ahead by 150 heat detection elements 5 of 10 × 15. The atmospheric temperature in the vehicle can be predicted from the temperature of the target area (for example, the inside of the door, seat, ceiling, glass, pillar, etc.). The temperature of the face at that time can be limited in its existence temperature range as shown in FIG. 17, for example. In other words, since there is a correlation that the higher the ambient temperature, the higher the temperature range of the face, the higher the temperature range of the face can be determined based on the ambient temperature.
[0053]
Subsequently, among the temperature distributions obtained from the infrared area sensor 3, the uppermost region among the regions that can be determined as the face position based on the determination result described above is determined as the face position (S109, S110, S111). ).
Therefore, the accuracy of the determination of the face position can be improved by further adding the condition of the face existing temperature range determined based on the ambient temperature in this way.
[0054]
Since the presence / absence of the occupant and the position of the face can be detected as described above, in the deployment control operation of the airbag system, after calculating the distance from the position of the face and body to the airbag, The development parameters are determined and control parameters are set. This control parameter includes the condition that the face and body are too close to the airbag, does not activate the airbag system, suppresses the deployment speed of the airbag, or reduces the total gas injection amount. Is to set.
[0055]
Therefore, for example, when the driver is driving close to the steering wheel at the timing when the airbag is activated, the airbag does not operate, the deployment speed of the airbag is suppressed, or the total gas injection amount is small. Therefore, the driver is not squeezed more strongly than the airbag.
[0056]
In addition, in the control operation of the air conditioning system, in addition to blowing the conditioned air intensively at the seating position of the person, the orientation is adjusted according to the position of the person's body or head, and at the other person's skin temperature When there is a part having a large temperature difference compared to the part, an appropriate conditioned air is blown so as to eliminate the temperature difference of the part.
[0057]
Therefore, the conditioned air having an appropriate temperature and blowing intensity can be blown regardless of the person's sitting position, physique, and skin temperature, so that all persons in the vehicle can feel comfortable.
[0058]
In addition, in the control operation of the security system, for example, when the temperature of the detection target area of the infrared area sensor rises due to the invasion of sunlight when a person gets off, the temperature of the entire area gradually increases substantially uniformly. It can be judged that it is sunlight and no warning is issued. On the other hand, when the temperature of a part of the detection target area of the infrared area sensor suddenly rises and the hot part moves, it can be determined that the person is an intruder and an alarm is issued.
[0059]
In addition to the driver's seat, the driver always exists when the vehicle moves, so that the measured absolute temperature can be corrected and confirmed by acquiring the driver's face temperature as described above.
[0060]
According to the present embodiment, in the configuration in which an occupant is detected based on a temperature difference from the background based on the temperature distribution in the detection target region of the infrared area sensor 3, when the door is opened, the temperature distribution outside the vehicle changes. Since the occupant is determined based on the occupant, the occupant can be determined even when the temperature in the passenger compartment is the same as the temperature of the occupant.
[0061]
In this case, since the temperature distribution of the detection target region is detected from the timing when the door lock is released, it is possible to reliably determine the occupant by tracking a large change in the temperature distribution before and after the door is opened. be able to.
[0062]
(Other embodiments)
By attaching the infrared area sensor 3 to a position as shown in FIG. 18, for example, it is possible to grasp not only the positional relationship between the front and rear of the occupant but also the position in the left-right direction. In this case, as shown in FIG. 19, determining the distance between the passenger and the door is effective for obtaining the deployment condition of the side surface protection airbag.
[0063]
Further, the presence / absence of the occupant and the face position are determined, and on which seat the occupant is seated with respect to the driver, the current determination contents such as deployment and non-deployment of the airbag are displayed as shown in FIG. By displaying on 17 (corresponding to display means), safety can be improved.
[0064]
In addition, since it is possible to determine the face position, temperature, etc. of the occupant, it is possible to prevent the child from getting out of the window, to prevent the child from being caught when the window is automatically closed at the time of locking. It can also be used to determine whether you are sick or have drunkness (decrease in face temperature) or whether you are drunk (increased face temperature).
[0065]
The present invention is not limited to the above embodiment, and can be modified or expanded as follows.
As a means for detecting the ambient temperature in the vehicle, a temperature sensor provided for an air conditioner may be used.
[0066]
It is also possible to use the infrared area sensor 3 as a solar radiation sensor. In other words, when the temperature of the window glass rises due to sunlight, it can be determined that the sunlight is inserted into the passenger compartment by gradually increasing the temperature of the window glass. By increasing the degree of air conditioning, it is possible to improve the comfort of people in the passenger compartment regardless of the sunlight in the passenger compartment.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the overall configuration of an embodiment of the present invention. FIG. 2 is a perspective view of a vehicle interior showing an arrangement position and a detection target area of an infrared area sensor unit. FIG. 4 is a schematic diagram showing the electrical configuration of the infrared area sensor. FIG. 5 is a diagram showing the detection timing of the infrared area sensor. FIG. 6 is a flowchart showing an occupant's judgment operation. The figure which shows the difference with the temperature change by the environment. [FIG. 8] The figure which shows the temperature change of one detection object area | region when a passenger | crew gets in a vehicle interior. [FIG. 9] The figure which shows the calculation timing of the temperature change amount in different time. FIG. 10 is a diagram showing a temperature change amount according to an elapsed time of a moving object having different moving speeds. FIG. 11 is a diagram showing an actual temperature distribution in a detection target region. FIG. 12 is obtained from an infrared camera. FIG. 13 is a diagram showing the temperature distribution in the target area. FIG. 13 is a diagram showing the detection target area. FIG. 14 is a diagram corresponding to FIG. 13 when the door is opened. FIG. 16 is a view corresponding to FIG. 15 in a state where a person is seated. FIG. 17 is a view showing the correlation between the atmospheric temperature and the temperature of the face. FIG. 18 is a view of FIG. 2 in another embodiment of the present invention. FIG. 19 is a schematic diagram showing a human detection state. FIG. 20 is a diagram showing an example of a display state of a display unit.
1 and 2 are infrared area sensor units, 3 is an infrared area sensor, 5 is a heat detection element, 8 is a signal detection / processing circuit (thermal image data creation means), 12 is various system control circuits (occupant judgment means, danger avoidance means) , Mood state determination means, correction means), 13 is a door lock switch (boarding detection means), 14 is a weight sensor, 15 is a door, 16 is a seat, and 17 is a display unit (display means).

Claims (2)

An infrared area sensor that has a plurality of heat sensing elements arranged two-dimensionally and detects a temperature distribution of a predetermined detection target region set in a vehicle interior at a detection timing determined by a detection cycle;
Thermal image data creating means for creating thermal image data based on the temperature distribution detected by the infrared area sensor;
Boarding / alighting detecting means for detecting that the occupant has performed a boarding or getting-off operation;
When it is detected by this getting-on / off detection means that the occupant has executed a boarding or getting-off operation, the thermal image data created by the thermal image data creating means is acquired at the detection timing, and the thermal image acquired at the previous detection timing is acquired. Occupant determination means for determining the presence and position of the occupant based on the temperature change obtained by comparing with the image data,
The infrared area sensor is mounted in a direction in which a temperature distribution outside the vehicle can be acquired when the vehicle door is opened,
The occupant determination means acquires the thermal image data created by the thermal image data creation means immediately after detecting that the occupant has performed a boarding or getting-off operation by the getting-on / off detection means, and when the door is opened, An occupant detection device for a vehicle, wherein the presence / absence and position of an occupant are determined based on a temperature change indicated by an occupant's thermal image data with a background outside the vehicle created by the thermal image data creation means through an opened door.   The vehicle occupant detection device according to claim 1, wherein the boarding / alighting detection unit determines that the boarding or the getting-off operation is performed when the occupant releases the door lock.

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