GB2366862A

GB2366862A - A camera arrangement for detecting an object

Info

Publication number: GB2366862A
Application number: GB0022575A
Authority: GB
Inventors: Anders Olsson; Karl Munsin; Marcus Klomark
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 2000-09-14
Filing date: 2000-09-14
Publication date: 2002-03-20
Anticipated expiration: 2020-09-14
Also published as: GB0022575D0; AU2001288165A1; GB2366862B; WO2002022404A1

Abstract

A camera arrangement for detecting an object such as a driver or a child seat located on, above or in front of a vehicle seat includes a camera (1) for creating an image of any object in that position, and also includes an electromagnetic wave source such as an infrared light source (2). Preferably an image created with the source (2) operational is stored in a first store and an image created with the source (2) non-operational is stored in a second store. The stored images are then subtracted and any object in the subtraction image is identified by an image processor. The position of the object may also be determined and used to inhibit or modify the operation of a safety device such as an airbag in the vehicle.

Description

<Desc/Clms Page number 1> DESCRIPTION OF INVENTION "IMPROVEMENTS IN OR RELATING TO A CAMERA ARRANGEMENT99 THE PRESENT INVENTION relates to a camera arrangement and more particularly relates to a camera arrangement for use with a safety device, in particular in a motor vehicle.

In connection with the deployment of a safety device in a motor vehicle it is sometimes important to be able to detect and identify objects located in the region above and in front of a vehicle seat. For example, it may be necessary to determine the position of at least part of the occupant of the seat, for example the head of the occupant of the seat, so as to be able to determine the position of the occupant of the seat within the seat. If the occupant is leaning forwardly, for example, it may be desirable to modify the deployment of equipment in the vehicle, such as a safety device in the forin of an airbag mounted directly in front of the occupant of the seat if an accident should occur. In the situation envisaged it may be appropriate only to inflate the airbag partially, rather than to inflate the ali-bag fully.

If the front seat of a vehicle is not occupied by a person, bUt Instead has a rear-facing child seat located on it, then it may be desirable to modify the

deployment of an airbag located in front of that seat, in the event that an accident should occur, in such a way that the airbag does not inflate at all. If the airbag did inflate it might eject the child from the rear facing child seat.

Many prior proposals have been made concerning techniques that can be utilised to determine the position of part of an occupant of a seat alld also to determine whether a seat is occupied by a rear-facing child seat. Some prior proposals have utilised optical techniques, and others have utilised techniques involving ultrasonic radiation or even "radar". In many prior arrangements the sensors have been mounted in front of the seat, and the signals derived from the sensors have been processed to calculate the distance between the occupant of the seat, or an item on the seat, and the sensors.

The present invention seeks to provide an improved camera arrangement which can be utilised to detect and evaluate objects on and above a vehicle seat. According to this invention there is provided a camera arraiigernent for detecting an object on, above or in front of a vehicle seat, the arrangement comprising an electromagnetic wave source sending out a electromagnetic wave beam which is directed towards the space above and in front of said seat and a camera for creating an image of any object Illuminated by the electromagnetic wave beam within the said space.

Preferably a processor is provided to process the detected image conveniently the processor controls or modifies the operation of equipment in the vehicle.

Preferably the equipment is an airbag, headrest, pillar loop or seat belt pretensioner.

Conveniently the processor is configured to determine whetliei- the seat is empty or whether it is occupied. The seat may be occupied by a person, or by a rear facing child seat.

Preferably the processor is configured to recognise, when the seat is occupied, predetermine objects or parts of objects and to determine tile position thereof relative to the seat.

Advantageously the processor is configured to recognise the head of a human occupant of the seat and to detennine the position thereof relative to the seat.

Conveniently the electromagnetic wave beam is a beam of light in the visible and/or non-visible part of the spectrum.

Preferably the electromagnetic wave beam consists solely of light in a non-visible part of the spectrum.

Conveniently the light beam is infra-red light.

Preferably means are provided to create an image with radiation source operative and to create a corresponding image with the radiation source interrupted and to subtract the second image from the first image to develop a resultant image, the resultant image comprising substantially only all image of objects within said space.

Conveniently, in use, the position of an object shown in tile resultant image is determined, and part of the second image at that position is added to

the resultant image to provide an enhanced image. In all alternative arrangement it is a selected part of the first linage that is added to tile composite image to create the final image. Preferably a single camera is used to create the first image and the second image. Advantageously means are provided to time multiplex the creation of a plurality of said first and second images. Conveniently the electromagnetic wave source and the camera are each located to one side of the seat, relative to the longitudinal axis of the vehicle. Preferably the camera and the electromagnetic wave source are located close to the longitudinal centre line of the vehicle. This invention also relates to a camera arrangement, tile camera arrangement comprising a camera having a predetermined field of view and a source generating a diverging beam of electromagnetic radiation directed towards said field of view, means being provided to interrupt the radiation, means being provided to take successive images from the camera when the radiation is present and when the radiation is interrupted, means beiilg provided to subtract an image from the camera when the radiation is interrupted frorn an image from the camera when the radiation is present to produce a resultant image. Preferably the radiation is in a non-visible part of the spectrum. Conveniently the radiation is infra-red light.

Advantageously the camera arrangement is mounted in a motor vehicle, the field of view of the camera being a region above and in front of a seat in the vehicle.

Preferably the said resultant image is processed a processor, all output signal from the processor modifying deployment of a safety device in the vehicle.

In order that the invention may be more readily understood, so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which: FIGURE I is a diagranimatic top plan view of part of the cabin of a motor vehicle illustrating a camera arrangement in accordance with the invention illustrating a light source that forms part of the camera arratigement in the operative condition; FIGURE 2 is a view corresponding to Figure I illustratDig, the light source in a non-operative condition; FIGURE 3 is a schematic view of the image obtained frorn the carnera arrangement with the light source in an operative condition; FIGURE 4 is a schematic view corresponding to Figure 4 showing the image obtained when the light source is not operative;

FIGURE 5 is a view showing a resultant image obtained by subtracting the image of Figure 4 from the image of Figure 3; and FIGURE 6 is a block diagram.

Referring initially to Figure 1, the camera arrangement of the present invention includes a camera 1. The camera I is responsive to a form of electromagnetic radiation, such as light, and may be responsive to visible light, but is preferably also responsive to light outside the visible spectrum, such as infra-red light. The camera may be solely responsive to light outside the visible spectrum.

The camera may a conventional television camera or a charge-coupled- device, or CMOS camera or any other camera capable of capturing a "visible" image or electromagnetic radiation image (which includes an image in the infra-red part of the spectrum) and converting that image to a corresponding electronic signal.

In the camera arrangement of Figure I the camera is associated with a source of electromagnetic radiation such as a light source 2. In the illustrated embodiment the light source 2 is an infra-red light source, that is to say a source of light which is in a non-visible part of the spectrum The light source generates diverging beam of light which is directed generally towards tile field of view of the camera 1. The divergent light coming from the light Source 2 is such that the illumination intensity of the resultant beam of light decreases with distance from the light source 2. The camera I is responsive to the light emitted by the light source.

In the embodiment of the invention illustrated in Figure I the camera I and the light source 2 are mounted in a motor vehicle, with the field of view of the camera I and the zone of illumination of the light source 2 being directed towards the area above a seat 3 of a motor vehicle. The seat is shown, in Figure I occupied by an occupant 4.

It is envisaged that the camera and the infra-red light source will be mounted in a fixed position towards the centre of the vehicle, with the field of view of the camera and the zone of illumination of the light being directed, across the seat 3, towards the window or door adjacent the seat 3. Thus only one occupant will be present within the field of view of the carnera 1, or only one child seat of such a child seat is mounted on the vehicle seat.

It is envisaged that the sensitivity of the camera I and the radiation intensity of the light source 2 will be so adjusted that the camera I is responsive to light reflected from the occupant 4 of the seat, but is not responsive (or is not so responsive) to light reflected from the parts of the cabin of the rnotor vehicle which are remote from the occupant 4, such as the door idjacent the occupant 4.

It is envisaged that the camera I will be utilised, in a first step, to capture an image with the light source 2 operational, as shown in Figure 1. In a subsequent step the camera captures an image with the light source non- operational, as shown in Figure 2.

Figure 3 illustrates schematically the image obtained in the first step, that is to say with the light source operational. Part of the image is the image of occupant, who is illuminated by the light source 2, and thus this part of the image is relatively bright. The rest of the image includes those parts of the

cabin of the vehicle detected by the camera I and also part of the image entering the vehicle through the window. Figure 4 illustrates the corresponding image taken with the light source 2 non-operational. The occupant 4 of the vehicle is not so bright, Jil this image, since the occupant is not illuminated by the light source 2, but the rest of tile image is virtually the same as the image of Figure 3. Successive signals from the camera I are passed to a processor 10 where signals representing the first image, with illumination, are stored in a store 11, and signals representing the second image, without illuminations, are stored in a store 12. The two signals are subtracted in the subtractor 13. Thus, effectively the second image, without illumination is subtracted, pixel-by-pixel, from the first image as shown in Figure 3, taken with the light source 2 operative. The resultant image, as shown in Figure 5, consists substantially of an image of only the occupant of the vehicle, that is to say only that part of the field of view of the camera I illuminated by light from the light source 2. Signals representing this image are passed to a processor 14. The processor 14 will process the image to determine whether tile seat is completely empty or is occupied in any way. The processor is configured to identify and recognise predetermined objects, such as child seats, or parts of objects, such as the head of a human occupant of the seat, and to determine the position thereof relative to the seat. Thus the processor will process tile image by determining the nature of the image, for example by determining whether the image is an image of an occupant of a seat or an image of a rear-facing child seat, and will determine the position of part of or the whole of the image.

In one embodiment of the invention, when the position of the object or part of the object has been determined, part of second image, that is the image without illumination, at the position occupied by the object, is added to the resultant image to provide an enhanced image. The enhanced image may be used to provide a more accurate assessment of the position of the object. The taking of successive images and the subtraction of signals representing the images and the processing step is repeated continuously, in a multiplex manner. If the image is an image of a rear-facing child seat the processor may, through a control arrangement 15, inhibit deployment of a safety device in the form of an airbag mounted in the dashboard in front of the seat. If the processor 14 determines that the image is an image of an occupant the processor will then determine if part of the occupant such as the head of the occupant, is in a predetermined part of the image. Because the field of view of the camera is fixed in position it is possible to detei-mine the position in the vehicle of part of the occupant by determining the position of that pail of the occupant within the image, It is thus possible to calculate the distance between part of the occupant, such as the head of the occupant and the dashboard or steering wheel to determine if the occupant is "in position" or "out of position". If the occupant is "out of position" the deployment of an airbag in front of the occupant may be modified by the control arrangement 15. The image processor 14 may also be adapted to determine the size of the image. Thus the processor will discriminate between a small seat occupant, such as a child, or a large seat occupant, such an obese adult. In dependence upon the deten-nination, the manner of deployment of an airbag provided to protect the occupant of the seat may be modified by the control arrangement 15.

It is to be appreciated that the camera arrangement as described above, will be sequentially operated with the light 2 on and with the light 2 off, with a subsequent subtraction of the detected images. Alternative mechanisins, such as a shutter, may be used to interrupt the beam of light. If an infra-red light is used, the light will not be in any way visible to the driver or Occupant of the vehicle and will thus not distract the driver or occupant of the vehicle, especially after dark. It is for this reason that it is preferred to Lise a light source that is not within the visible spectrum. Whilst the invention has been described with reference to the modification of deployment of a safety device such as an airbag it is to be appreciated that the safety device whose deployment is modified rnay cornprise alternative forms of safety device such as a pre-tensioner adapted to pre-tension a safety belt, a pillar loop, or an headrest on a seat. In the present specification "comprise" means "includes or consists of' and "comprising" means "including or consisting of'. The features disclosed in the foregoing description, or the following Claims, or the accompanying drawings, expressed in their specific fornis or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for reallsing the invention in diverse forms thereof

Claims

CLAIMS 1. A camera arrangement for detecting an object on, above or in front of a vehicle seat, the arrangement comprising an electromagnetic wave source sending out a electromagnetic wave beam which is directed towards the space above and in front of said seat and a camera for creating an image of ally object illuminated by the electromagnetic wave beam within the said space.
2. A camera arrangement according to claim I wherein a processor is provided to process the detected image.
3. An arrangement according to claim 2 wherein the processor is configured to determine whether the seat is empty or whether it is occupied.
4. An arrangement according to claim 3 wherein the processor is configured to recognise, when the seat is occupied, predetermine objects or parts of objects and to determine the position thereof relative to the seat.
5. An arrangement according to claim 5 wherein the processor is configured to recognise the head of a human occupant of the seat and to determine the position thereof relative to the seat.
6. An arrangement according to any one of claims 2 to 5 wherein the processor controls or modifies the operation of equipment in the velilcle.
7. An arrangement according to claim 6 wherein the equipment is an airbag, headrest, pillar loop or seat belt pretensioner.

<Desc/Clms Page number 12>
8. A camera arrangement according any one of the preceding claims wherein the electromagnetic wave beam is a beam of light in the visible and/or non-visible part of the spectrum.
9. An arrangement according to any one of the preceding claims wherein the electromagnetic wave beam consists solely of light in a non-visible pail of the spectrum.
10. An arrangement according to claim 9 wherein the light beam is infra-red light.
11. An arrangement according to any one of the preceding clainis wherein means are provided to create an image with radiation source operative and to create a corresponding image with the radiation source interrupted and to subtract the second image from the first image to develop a resultant image, the resultant image comprising substantially only an image of objects witliiii said space.
12. An arrangement 4ccording to claim I I wherein, in use, the position of an object shown in the resultant image is determined, and part of the second irnage at that position is added to the resultant image to provide an enhanced iniage.
13. A camera arrangement according to claims 11 or 12 wherein a single camera is used to create the first image and the second image.
14. An arrangement according to any one of the preceding clainis wherein means are provided to time multiplex the creation of a plurality of said first and second images.

<Desc/Clms Page number 13>
15. An arrangement according to any one of the preceding claims wherein the electromagnetic wave source and the camera are each located to one side of the seat, relative to the longitudinal axis of the vehicle.
16. An arrangement according to claim 15 wherein the camera and the electromagnetic wave source are located close to the longitudinal centre line of the vehicle.
17. A camera arrangement, the camera arrangement comprising a camera having a predetermined field of view and a source generating a diverging beam of electromagnetic radiation directed towards said field of view, means being provided to interrupt the radiation, means being provided to take successive images from the camera when the radiation is present and when the radiation is interrupted, means being provided to subtract an image fi-om the carnera when the radiation is interrupted from an image from the camera when the radiation is present to produce a resultant image.
18. An arrangement according to claim 17 wherein the radiation is in a non- visible part of the spectrum.
19. An arrangement according to claim 18 wherein the light is infra-red light.
20. A camera arrangement according to claim 17, 18 or 19 wherein the camera arrangement is mounted in a motor vehicle, the field of view of tile camera being a region above and in front of a seat in the vehicle.

<Desc/Clms Page number 14>
21. An arrangement according to claim 20 wherein the said reSUItant it-nage is processing a processor, an output signal from the processor modifying deployment of a safety device in the vehicle.
22. A camera arrangement substantially as herein described with reference to and as shown in the accompanying drawings.
23. Any novel feature or combination of features disclosed hereiii.