JP4202908B2 - Vehicle occupant detection system - Google Patents

Description

  The present invention belongs to the technical field of a vehicle occupant detection system using an infrared sensor.

Conventionally, in an occupant detection system for a vehicle, when detecting an occupant or a human body part using a matrix type infrared sensor, a human body temperature is set as a detection judgment threshold value, and a detection value is set based on the threshold value. Human body detection and human body local detection are performed by bipolarization (for example, refer to Patent Document 1).
JP 11-295440 A

  However, in the above prior art, when detecting a plurality of occupants using a matrix-type infrared sensor with relatively low detection accuracy, all sensor detection ranges are identified with the same threshold value. Depending on the case, the detection distance may vary. As a result, a difference in detection temperature occurs due to a difference in detection distance and a difference in sensitivity, making it difficult to accurately detect an occupant. In addition, because the detection area of the thermal image varies depending on the perspective difference, depending on the setting of the threshold value of the detection area, there is a risk that the occupant will overlap when viewed from the sensor, and accurate detection may not be possible. There was a problem.

  The present invention has been made paying attention to the above problems, and the object of the present invention is to detect a plurality of occupants, to detect the occupant's face area, and to use an inexpensive matrix infrared sensor with relatively low detection sensitivity. An object of the present invention is to provide a vehicle occupant detection system capable of accurately detecting a position.

In order to achieve the above object, in the present invention, in a vehicle occupant detection system for detecting an occupant based on a detection signal of an infrared sensor provided in a vehicle interior, a seating state detection unit that detects an occupant of each seat; based on the detected seating position, with the occupant detection range setting means for setting an occupant detection range of each seat, based on the occupant detection range set, the occupant detection means for detecting each passenger, the said The seating state detection means is a seat belt wearing detection means for detecting the wearing of a seat belt, and the occupant detection range setting means is a seat in which a seat belt is worn. Larger than the passenger detection range.

  Therefore, in the present invention, in order to detect each occupant based on the occupant detection range according to the seating state, even if an inexpensive matrix infrared sensor with relatively low detection sensitivity is used, a plurality of occupant detection, It is possible to accurately detect the face area and position of the occupant.

  The best mode for carrying out the present invention will be described below based on the first embodiment.

First, the configuration will be described.
FIG. 1 is a system diagram of a vehicle occupant detection system 100, and FIG. 2 is a perspective view of the interior of the vehicle in which the vehicle occupant detection system 100 is installed.

  As shown in FIG. 1, the vehicle occupant detection system 100 according to the first embodiment includes a matrix infrared sensor 10, a sensor control unit 20, a seat belt 30, a seat belt switch 31, a seat 40, a pressure sensor 41, and a weight sensor 42. The communication line 60 and the in-vehicle device 50 are the main components.

  As shown in FIG. 2, the infrared sensor 10 is provided at a position in the center of the upper end of the windshield inside the vehicle at a position where all the occupants can be detected even when all the occupants are seated in the vehicle. Connected.

  The infrared sensor 10 detects an occupant by detecting the temperature of the upper body around the head of each occupant.

  The seat belt switch 31 is provided in a seat belt buckle for inserting and fixing the tongue plate of the seat belt 30, detects insertion of the tongue plate, and outputs a detection signal to the occupant detection control unit 21.

  The seat belt tension sensor 32 is provided in a seat belt retractor that winds up the seat belt 30, detects the tension of the seat belt 30, and outputs a detection signal to the occupant detection control unit 21.

  The pressure sensor 41 is provided on the seat back 40 a of the seat 40, detects a state in which the occupant leans back when seated, and outputs a detection signal to the occupant detection control unit 21.

  The weight sensor 42 is provided in a seating portion of the seat 40, detects seating by detecting a passenger load, and outputs a detection signal to the passenger detection control unit 21.

  The in-vehicle device 50 includes an air conditioner control unit 51, an air bag control unit 52, and an audio control unit 53. The air conditioner control unit 51, the air bag control unit 52, and the audio control unit 53 are each sensored by a communication line 60. It connects with the control unit 20 and outputs a detection signal to the occupant detection control unit 21.

  The sensor control unit 20 is a control device that is provided inside an instrument panel in the vehicle and controls the threshold value of the infrared sensor 10. The sensor control unit 20 includes an occupant detection control unit 21.

  The occupant detection control unit 21 detects an occupant based on signals from the infrared sensor 10, the seat belt switch 31, the pressure sensor 41, the weight sensor 42, and the in-vehicle device 50.

Next, the operation will be described.
[Detection sensitivity correction]
FIG. 3 is a view of the inside of the vehicle viewed from the infrared sensor 10.

FIG. 3 shows a situation where the driver's seat occupant A and the rear seat occupant B are seated on the left side of the driver's seat and the rear seat.
In this case, as shown in FIG. 4, there is a difference between the distance L1 from the infrared sensor 10 to the driver's seat occupant A and the distance L2 to the rear seat occupant B.

FIG. 5 is a cross-sectional view of the inside of the vehicle on which the vehicle occupant detection system 100 is mounted.
For example, in FIG. 5, when each occupant moves his / her head, the distance between each occupant and the infrared sensor 10 changes. Depending on the front and back of the occupant's head, the distance L1 between the infrared sensor 10 and the driver's seat occupant A is as follows:
L1-a or L1 + b
And the distance between the infrared sensor 10 and the rear seat occupant B is moved forward c and backward d
L2-c or L2 + d
And change.

FIG. 6 is a diagram showing the relationship between the detection sensitivity threshold of the infrared sensor 10 and the detection distance.
The sensor detection sensitivities for the front seat detection distance L1 and the rear seat detection distance L2 are indicated by A1 and A2. The detection sensitivity when the occupant moves in the front-rear direction is also A1 + e for the detection distance L1-a, A1 + f for L1 + b, A2 + g for L2-c, and A2 + h for L2 + d It becomes.

FIG. 7 is a diagram illustrating the relationship between the detection area threshold of the infrared sensor 10 and the detection distance.
Similar to the relationship between the detection sensitivity and the detection distance in FIG. 6, the detection area for the front seat detection distance is B1, and the detection area for the rear seat detection distance is B2. Similarly, the detection area is B1 + i with respect to the detection distance L1-a, B1 + j with respect to L1 + b, B2 + k with respect to L2-c, and B2 + m with respect to L2 + d.

  From FIG. 6 and FIG. 7, the detection threshold value differs depending on the distance between the occupant and the infrared sensor 10. Therefore, even when the body surface temperature of the occupant to be detected is the same, the detection distance is different. It is shown that the values are different.

FIG. 8 is a diagram showing detection areas and detection values set for each occupant.
When the occupant is seated in the front seat, the tongue plate of the seat belt 30 of the front seat is inserted into the seat belt buckle and the seat belt 30 is mounted, the weight sensor 42 detects the seating and is installed in the seat belt buckle. The seat belt switch 31 detects the seat belt 30 being worn.

  The weight sensor 42 and the seat belt switch 31 output a seating signal and a seat belt wearing signal to the occupant detection control unit 21.

  Upon receiving the seat belt 30 detection signal and the seating signal, the occupant detection control unit 21 determines that the driver's seat occupant does not move greatly from a fixed position on the seat, and divides the sensor detection area into predetermined areas. The occupant detection is started.

  Here, each area corresponds to each seat of the front seat and the rear seat, and is categorized so that an occupant seated in the seat can be detected, and two areas corresponding to two seats of the front seat and three areas of the rear seat It is divided into.

  The driver seat detection area is a driver seat occupant detection area 101 surrounded by coordinates 1 to 5, for example, as shown in FIG. If the driver's seat occupant is wearing the seat belt 30, it is set so that the driver's seat occupant can be detected almost certainly within this area.

  Similarly, the passenger seat detection area is a passenger seat occupant detection area 103 surrounded by coordinates 6 to 10 where the passenger seat occupant can be reliably detected when the seat belt is worn.

  The rear seat occupant detection area 102 which is a detection area of the rear seat is an area excluding the driver seat occupant detection area 101 and the passenger seat occupant detection area 103 in the in-vehicle area detected by the infrared sensor 10.

  Thus, when the detection signal is received from the seat belt switch 31 in each detection area, the occupant detection control unit 21 divides the detection area of the infrared sensor into each of the above-described areas, and detects the area that receives the detection signal. Start.

  In FIG. 8, the matrix type infrared sensor 10 performs temperature detection by dividing a detection region into a matrix type. The dot pattern shown here is a matrix-type dot pattern divided by the infrared sensor 10 and is shown in a darker color as the detection temperature is higher.

  As described above, there is a difference in the detection distance between the front seat and the rear seat, and thus there is a difference in the temperature detected by the infrared sensor 10. The detected temperature of the front seat is higher and the detected temperature of the rear seat is lower.

  Further, as shown in FIG. 8, the detection area of the front seat occupant and the rear seat occupant varies depending on the difference in the detection distance between the front seat and the rear seat. The detection area of the front seat occupant is large, and the detection area of the rear seat occupant is small.

  As described above, detection of the front seat occupant and the rear seat occupant has a difference in detection sensitivity due to a difference in detection temperature and detection area due to a difference in detection distance from the infrared sensor 10. In order to correct this difference in detection sensitivity, the detection temperature and the detection area of each of the above-mentioned driver seat occupant detection area, passenger seat occupant detection area, and rear seat detection area are taken into account in consideration of the characteristics of the infrared sensor 10. Set the correction value in advance.

  When detecting, the correction value is used to correct and optimize the detection sensitivity to detect front and rear occupants.

[Crew detection]
FIG. 9 is a diagram illustrating a driver seat occupant A and a driver seat occupant detection area 101.
When the driver's seat occupant A is seated in the driver's seat and the seat belt 30 is worn, the weight sensor 42 detects the seating as described above, and the seat belt switch 31 detects the wearing of the seat belt 30 and detects the detection signal. A detection signal is output to the control unit 21.

  The occupant detection control unit 21 that has received the seating detection signal of the driver's seat occupant A and the seat belt 30 sets the driver's seat occupant detection area 101 as described above, and detects the occupant's temperature.

FIG. 10 is a diagram showing a driver seat occupant A, a passenger seat occupant C, a driver seat occupant detection area 101, and a passenger seat occupant detection area 103.
Also in FIG. 10, as in the setting of the driver seat occupant detection area 101 in FIG. 9, the occupant detection control unit 21 detects the detection signals of the weight sensor 42 and the seat belt switch 31 for each seat, and the driver seat occupant detection area 101. The passenger seat occupant detection area 103 is set to detect the occupant temperature.

FIG. 11 is a diagram showing a driver seat occupant A, a passenger seat occupant C, and a rear seat occupant B, a driver seat occupant detection area 101, a passenger seat occupant detection area 103, and a rear seat occupant detection area 102.
Similarly, in FIG. 11, the occupant detection control unit 21 detects detection signals of the weight sensor 42 and the seat belt switch 31 for each seat, and sets a detection area for each seat to detect the occupant temperature.

[Occupant detection control process]
FIG. 12 is a flowchart showing the flow of the occupant detection control process executed by the vehicle occupant detection system 100.

  In step S1, the infrared sensor 10 detects the in-vehicle temperature, the sensor control unit 20 is set to read the sensor temperature characteristic at the in-vehicle temperature and perform proper detection, and the process proceeds to step S2.

  In step S2, the occupant detection control unit 21 determines the presence of the driver's seat occupant A based on the detection signals of the weight sensor 42 and the seat belt switch 31, and if present, the process proceeds to step S3, and if not present, the process proceeds to step S5. To do.

  In step S3, the occupant detection control unit 21 sets the driver's seat occupant detection area 101, and the process proceeds to step S4.

  In step S4, correction values for the detected temperature and the detected area are set according to the detected distance to the driver's seat occupant A, and the process proceeds to step S5.

  In step S5, the occupant detection control unit 21 determines the presence of the passenger seat occupant C based on the detection signals of the weight sensor 42 and the seat belt switch 31, and if present, proceeds to step S6, otherwise proceeds to step S8. To do.

  In step S6, the occupant detection control unit 21 sets the passenger seat occupant detection area 103, and the process proceeds to step S7.

  In step S7, the detection temperature and the detection area correction value are set according to the detection distance to the passenger seat occupant C, and the process proceeds to step S8.

  In step S8, the occupant detection control unit 21 determines the presence of the rear seat occupant B based on the detection signals of the weight sensor 42 and the seat belt switch 31, and if present, the process proceeds to step S9. If not present, the process proceeds to step S11. To do.

  In step S9, the occupant detection control unit 21 sets the rear seat occupant detection area 102, and the process proceeds to step S10.

  In step S10, the detection temperature and the detection area correction values are set according to the detection distance to the rear seat occupant B, and the process proceeds to step S11.

  In step S11, the presence of an occupant is detected, and the occupant detection control unit 21 detects the occupant of the seat in which each detection area is set, and the process proceeds to step S12.

  In step S12, the occupant detection control unit 21 outputs the detection result to the in-vehicle device 50, and the process returns to step S1.

[Occupant detection control action]
(1) When the driver's seat occupant A sits in the driver's seat and wears the seat belt 30 and there is no other occupant or the other occupant does not wear the seat belt 30, the steps in the flowchart of FIG. Step S1 → Step S2 → Step S3 → Step S4 → Step S5 → Step S8 → Step S11 → Step S12
That is, the driver's seat occupant detection area 101 is set, and the driver's seat occupant A is detected.

(2) Driver's seat occupant A and passenger's seat occupant C are seated on the driver's seat and passenger's seat and seatbelt 30 is installed, and rear seat occupant B does not exist or rear seat occupant B is seated on seatbelt 30. If not, in the flowchart of FIG.
Step S1 → Step S2 → Step S3 → Step S4 → Step S5 → Step S6 → Step S7 → Step S8 → Step S11 → Step S12
That is, the driver seat occupant detection area 101 and the passenger seat occupant detection area 103 are set, and the driver seat occupant A and the passenger seat occupant C are detected.

(3) When the driver's seat occupant A, the passenger seat occupant C, and the rear seat occupant B are seated and wearing the seat belt 30, in the flowchart of FIG. 12, step S1, step S2, step S3, step S4, Step S5 → Step S6 → Step S7 → Step S8 → Step S9 → Step S10 → Step S11 → Step S12
That is, the driver's seat occupant detection area 101, the passenger's seat occupant detection area 103, and the rear seat occupant detection area 102 are set, and occupants are detected.

[Changing passenger detection area]
FIG. 13 is a diagram showing that the driver's seat occupant detection area 101 is enlarged when the driver's seat occupant A is not wearing the seat belt 30.

  When the driver's seat occupant A removes the seat belt 30, the occupant detection control unit 21 detects that the detection signal of the seat belt switch 31 is OFF, and the driver's seat occupant detection area 101 that has been fixed so far can be changed. To do.

  At this time, the occupant detection control unit 21 expands the driver occupant detection area 101 so that the infrared sensor 10 can detect the movement following the movement of the driver occupant A that has been detected so far.

  FIG. 14 is a diagram showing that both the driver's seat occupant A and the passenger's seat occupant C remove the seat belt 30, and both the driver's seat occupant detection area 101 and the passenger's seat occupant detection area 103 are expanded.

  Similar to the driver-seat occupant detection area 101 in FIG. 13, when the driver-seat occupant A removes the seat belt 30, the driver-seat occupant detection area 101 that has been fixed by the occupant detection control unit 21 becomes variable. Enlarge to match the movement of A.

  Similarly, the passenger seat occupant C is also variable, and the passenger seat occupant detection area 103 is expanded in accordance with the movement of the passenger occupant C.

[In-vehicle device control]
As shown in FIG. 1, the occupant detection control unit 21 that has detected the occupant inputs the detection result to each control device (the air conditioner control unit 51, the airbag control unit 52, and the audio control unit 53) of the in-vehicle device 50.

  In response to the input of the detection result, the air conditioner control unit 51 opens the air conditioner outlet of the seat where the occupant is detected, closes the outlet of the seat not detected, and performs air conditioning according to the seating position of the occupant.

  The airbag control unit 52 turns on the switch of the airbag of the seat where the occupant is detected and the seat belt tension sensor 32, detects a sudden change in the tension of the seat belt 30, and activates the airbag.

  Also, the audio control unit 53 turns on an audio speaker near the seat where the occupant is detected, and sets an acoustic environment according to the seating position of the occupant.

Next, the effect will be described.
In the car navigation device according to the first embodiment, the following effects can be obtained.

(1) The occupant detection area for each seat is set based on the detection signal of the seat belt switch 31, and the infrared sensor 10 detects the occupant based on the occupant detection area, thereby identifying the position of the occupant to some extent. It becomes possible to detect from.
Therefore, in order to detect each occupant based on the occupant detection range according to the seating state, even if an inexpensive matrix type infrared sensor with relatively low detection sensitivity is used, a plurality of occupant detections and occupant face areas and positions are detected. Detection can be performed accurately.
In addition, since it is possible to detect occupants in all seats with a single infrared sensor, it is possible to expect a simplified structure and improved layout of the entire vehicle occupant detection system.

(2) The occupant detection judgment threshold value of the infrared sensor 10 for the rear seat occupant B far from the infrared sensor 10 is lower than the occupant detection judgment threshold value of the infrared sensor 10 for a driver seat passenger and a passenger seat passenger closer to the infrared sensor. Set.
Therefore, it is possible to avoid the detection of different values and inaccurate detection even though the body surface temperatures of the front seat and the rear seat are the same, and more accurate passenger detection can be performed. Become.

(3) The occupant detection area of the seat where the seat belt 30 is not worn is set larger than the occupant detection area of the seat where the seat belt 30 is worn.
Accordingly, even if a seat occupant not wearing the seat belt 30 moves in the vehicle, the detection area can be expanded in accordance with the movement, and more reliable occupant detection can be performed.
For example, as shown in FIGS. 13 and 14, the infrared sensor 10 can detect an occupant by enlarging the occupant detection area in accordance with the movement of the occupant not wearing the seat belt 30.

(Other examples)
Although the best mode for carrying out the present invention has been described based on the first embodiment, the specific configuration of the present invention is not limited to the first embodiment.

In the first embodiment, the detection range of the infrared sensor is divided into the driver seat detection area, the passenger seat occupant detection area, and the rear seat detection area. However, the detection range can be divided into other divisions as long as the position of the occupant can be specified to some extent. The method may be used.
For example, the position of the occupant may be made more accurate, for example, the rear seat is further divided into three.

In the first embodiment, the occupant detection area is fixed and variable depending on whether the seat belt is worn or not. However, using the pressure sensor shown in FIG. 1, the detection area may be varied depending on the seating state of the occupant. .
In this case, since the weight shift accompanying the movement of the occupant can be easily detected by the change in the value of the pressure sensor, it is possible to more appropriately determine whether the detection area is fixed or variable.

When performing control by inputting an occupant detection result to an in-vehicle device, the control load increases if detection control of each area is performed at once.
For this reason, in the case of an in-vehicle device with sufficient responsiveness such as an air conditioner, detection may be performed by changing the detection area for each scan of the infrared sensor and reducing the control load.

1 is a system diagram of a vehicle occupant detection system. It is a perspective view of the inside of a vehicle in which a vehicle occupant detection system is installed. It is the figure in the vehicle seen from the infrared sensor. It is a top view inside a vehicle carrying a vehicle occupant detection system. It is sectional drawing inside the vehicle carrying a vehicle occupant detection system. It is a figure which shows the relationship between the detection sensitivity of an infrared sensor, and a detection distance. It is a figure which shows the relationship between the detection area of an infrared sensor, and detection distance. It is the figure which showed the detection area and detection value which are set for every passenger | crew. It is a figure which shows a driver's seat passenger | crew and a driver's seat passenger | crew detection area. It is a figure which shows a driver seat passenger | crew, a passenger seat passenger | crew, a driver seat passenger | crew detection area, and a passenger seat passenger | crew detection area. It is a figure which shows a driver seat passenger | crew, a passenger seat passenger | crew, and a rear seat passenger | crew and a driver seat passenger | crew detection area, a passenger seat passenger | crew detection area, and a rear seat passenger | crew detection area. It is a flowchart which shows the flow of the passenger | crew detection control performed with the passenger | crew detection system for vehicles. It is the figure which showed that a driver's seat occupant detection area was expanded when the driver's seat occupant was not wearing a seat belt. It is the figure which showed that a driver's seat passenger detection area and a passenger seat passenger detection area expanded together.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Infrared sensor 20 Sensor control part 21 Crew detection control part 30 Seat belt 31 Seat belt switch 32 Seat belt tension sensor 40 Seat 40a Seat back 41 Pressure sensor 42 Weight sensor 50 In-vehicle apparatus 51 Air-conditioner control part 52 Air bag control part 53 Audio control Part 60 Communication line 100 Vehicle occupant detection system 101 Driver's seat occupant detection area 102 Passenger seat occupant detection area 103 Rear seat occupant detection area A Driver's seat occupant B Rear seat occupant C Passenger's seat occupant

Claims (2)

In the vehicle occupant detection system for detecting the occupant based on the detection signal of the infrared sensor provided in the passenger compartment,
A seating state detecting means for detecting an occupant of each seat;
Occupant detection range setting means for setting an occupant detection range for each seat based on the detected seating state;
Occupant detection means for detecting each occupant based on the set occupant detection range;
Equipped with a,
The seating state detection means is a seat belt wearing detection means for detecting the wearing of a seat belt,
The vehicle occupant detection system is characterized in that the occupant detection range setting means makes an occupant detection range of a seat without a seat belt larger than an occupant detection range of a seat with a seat belt. The vehicle occupant detection system according to claim 1,
The vehicle occupant detection means sets an infrared sensor occupant detection determination threshold for an occupant far from the infrared sensor to be lower than an occupant detection determination threshold of the infrared sensor for an occupant close to the infrared sensor. Occupant detection system.

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