Method and Apparatus for Detecting the Presence of a Child Seat

The present invention is related to methods and apparatus for detecting the presence of a child seat, more particularly, to methods and apparatus for detecting the presence of a child seat in a rear-facing position. The detected presence of such a rear-facing child seat may be used to control or affect the operation of a vehicular system, such as an airbag restraint system.

In 1984, the National Highway Traffic Safety Administration (NHTSA) of the U.S. Department of Transportation issued a requirement for frontal crash protection of automobile occupants. This regulation mandated "passive occupant restraints" for all passenger cars by 1992. A more recent regulation requires both driver and passenger side airbags on all passenger cars and light trucks by 1998. In addition, the demand for airbags is accelerating in both Europe and Japan and it is expected that, within a few years, all vehicles produced in these areas (36 million vehicles) and eventually worldwide (50 million vehicles) will be equipped with airbags as standard equipment.

Whereas thousands of lives have been saved by airbags, significant improvements can be made. As discussed in detail in copending patent application Ser. No. 08/040,978 cross-referenced above, and included herein by reference, for a variety of reasons, vehicle occupants can be or get too close to the airbag before it deploys and can be seriously injured or killed upon deployment of the airbag.

Also, a child in a rear facing child seat, which is placed on the right front passenger seat, is in danger of being seriously injured if the passenger airbag deploys. This has now become an industry-wide concern and the US automobile industry is urgently searching for an easy, economical solution, which will prevent the deployment of the passenger side airbag if a rear facing child seat is present. An improvement on the invention disclosed in the above-referenced patent application, as will be disclosed in greater detail below, includes more sophisticated means to identify objects within the passenger compartment and will solve this problem.

Initially, these systems will solve the out-of-position occupant and the rear facing child seat problems related to current airbag systems and prevent unneeded deployments when a seat is unoccupied. Airbags are now under development to protect rear seat occupants in vehicle crashes. A system will therefore be needed to detect the presence of occupants, position, i.e., determine if they are out-of-position, and type, e.g., to identify the presence of a rear facing child seat in the rear seat. Future automobiles can be expected to have eight or more airbags as protection is sought for rear seat occupants and from side impacts. In addition to eliminating the disturbance of unnecessary airbag deployments, the cost of replacing these airbags will be excessive if they all deploy in an accident. The improvements described below minimize this cost by not deploying an airbag for a seat, which is not occupied by a human being. An occupying item of a seat may be a living occupant such as a human being or dog, another living organism such as a plant, or an inanimate object such as a box or bag of groceries.

A device to monitor the vehicle interior and identify its contents is needed to solve these and many other problems. For example, once a Vehicle Interior Identification and Monitoring System (VIMS) for identifying and monitoring the contents of a vehicle is in place, many other products become possible including the following:

Inflators now exist which will adjust the amount of gas flowing to the airbag to account for the size and position of the occupant and for the severity of the accident. The vehicle identification and monitoring system of this invention will control such inflators based on the presence and position of vehicle occupants or of a rear facing child seat.

Side impact airbag systems began appearing on 1995 vehicles. The danger of deployment induced injuries will exist for side impact airbags as they now do for frontal impact airbags. A child with his head against the airbag is such an example. The system of this invention will minimize such injuries.

Future vehicles may be provided with a standard cellular phone as well as the Global Positioning System (GPS), an automobile navigation or location system, is now available on at least one vehicle model. In the event of an accident, the phone may automatically call 911 for emergency assistance and report the exact position of the vehicle. If the vehicle also has a system as described below for monitoring each seat location, the number and perhaps the condition of the occupants could also be reported. In that way, the emergency service (EMS) would know what equipment and how many ambulances to send to the accident site.

Vehicle entertainment system engineers have stated that the quality of the sound in the vehicle could be improved if the number, size and location of occupants and other objects were known. This information can be provided by the vehicle interior identification and monitoring system of this invention.

Similarly to the entertainment system, the heating, ventilation and air conditioning system (HVAC) could be improved if the number, attributes and location of vehicle occupants were known. This can be used to provide a climate control system tailored to each occupant, for example, or the system can be turned off for certain seat locations if there are no occupants present at those locations.

In some cases, the position of a particular part of the occupant is of interest such as: (a) his hand or arm and whether it is in the path of a closing window so that the motion of the window needs to be stopped; (b) the position of the shoulder so that the seat belt anchorage point can be adjusted for the best protection of the occupant; or, (c) the position of the rear of the occupants head so that the headrest can be adjusted to minimize whiplash injuries in rear impacts.

The above applications illustrate the wide range of opportunities, which become available if the identity and location of various objects and occupants, and some of their parts, within the vehicle were known. Once the system is operational, it would be logical for the system to also incorporate the airbag electronic sensor and diagnostics system (SDM) since it needs to interface with SDM anyway and since they could share computer capabilities which will result in a significant cost saving to the auto manufacturer. For the same reasons, it would be logical for VIMS to include the side impact sensor and diagnostic system. As the VIMS improves to where such things as the exact location of the occupants ears and eyes can be determined, even more significant improvements to the entertainment system become possible through the use of noise canceling sound, and the rear view mirror can be automatically adjusted for the driver's eye location. Another example involves the monitoring of the driver's behavior over time which can be used to warn a driver if he or she is falling asleep, or to stop the vehicle if the driver loses the capacity to control it.

Using an advanced VIMS, as explained below, the position of the driver's eyes can be accurately determined and portions of the windshield can be selectively darkened to eliminate the glare from the sun or oncoming vehicle headlights. This system uses electro-chromic glass, a liquid crystal coating on the glass, or other appropriate technology, and detectors to detect the direction of the offending light source. In addition to eliminating the glare, the sun visor can now also be eliminated.

The present invention adds more sophisticated pattern recognition capabilities such as fuzzy logic systems, neural network systems or other pattern recognition computer based algorithms to the occupant position measurement system disclosed in the above referenced copending patent application and greatly extends the areas of application of this technology. An example of such a pattern recognition system using neural networks using sonar is discussed in two papers by Gorman, R. P. and Sejnowski, T. J. "Analysis of Hidden Units in a Layered Network Trained to Classify Sonar Targets", Neural Networks, Vol.1. pp 75-89, 1988, and "Learned Classification of Sonar Targets Using a Massively Parallel Network", IEEE Transactions on Acoustics, Speech, and Signal Processing, Vol. 36, No. 7, July 1988.

"Pattern recognition" as used herein will mean any system which processes a signal that is generated by an object, or is modified by interacting with an object, in order to determine which one of a set of classes that the object belongs to. Such a system might determine only that the object is or is not a member of one specified class, or it might attempt to assign the object to one of a larger set of specified classes, or find that it is not a member of any of the classes in the set. The signals processed are generally electrical signals coming from transducers which are sensitive to either acoustic or electromagnetic radiation and if electromagnetic, they can be either visible light, infrared, ultraviolet or radar.

"To identify" as used herein will mean to determine that the object belongs to a particular set or class containing objects having a similar form. The class may be one containing all rear facing child seats, one containing all human occupants, or all human occupants not sitting in a rear facing child seat depending on the purpose of the system. In the case where a particular person is to be recognized, the set or class will contain only a single element, the person to be recognized.

Some examples follow:

In a passive infrared system, a detector receives infrared radiation from an object in its field of views in this case the vehicle occupant, and determines the temperature of the occupant based on the infrared radiation. The VIMS can then respond to the temperature of the occupant, which can either be a child in a rear facing child seat or a normally seated occupant, to control some other system. This technology could provide input data to a pattern recognition system but it has limitations related to temperature. The sensing of the child could pose a problem if the child is covered with blankets. It also might not be possible to differentiate between a rear facing child seat and a forward facing child seat. In all cases, the technology will fail to detect the occupant if the ambient temperature reaches body temperature as it does in hot climates. Nevertheless, for use in the control of the vehicle climate, for example, a passive infrared system that permits an accurate measurement of each occupant's temperature is useful.

In a laser optical system an infrared laser beam is used to momentarily illuminate an object, occupant or child seat in the manner as described, and illustrated in FIG. 8, of U.S. Pat. No. 5,653,462 cross referenced above. In some cases, a charge-coupled device (a type of TV camera also referred to as a CCD array) or a CMOS device is used to receive the reflected light. The laser can either be used in a scanning mode, or, through the use of a lens, a cone of light can be created which covers a large portion of the object. In each case, a pattern recognition system, as defined above, is used to identify and classify, and can be used to locate, the illuminated object and its constituent parts. This system provides the most information about the object and at a rapid data rate. Its main drawback is cost which is considerably above that of ultrasonic or passive infrared systems. As the cost of lasers comes down in the future, this system will become more competitive. Depending on the implementation of the system, there may be some concern for the safety of the occupant if the laser light can enter the occupant's eyes.

Radar systems have similar properties to the laser system discussed above. The wavelength of a particular radar system can limit the ability of the pattern recognition system to detect object features smaller than a certain size. Once again, however, there is some concern about the health effects of radar on children and other occupants. This concern is expressed in various reports available from the United States Food and Drug Administration Division of Devices.

The ultrasonic system is the least expensive and potentially provides less information than the laser or radar systems due to the delays resulting from the speed of sound and due to the wave length which is considerably longer than the laser systems. The wavelength limits the detail, which can be seen by the system. Additionally, ultrasonic waves are sometimes strongly affected by thermal gradients within the vehicle such as caused by flowing air from the heater or air conditioner or as caused by the sun heating the top of the vehicle causing the upper part of the passenger compartment to have a higher temperature than the lower part. In spite of these limitations, as shown below, ultrasonics can provide sufficient timely information to permit the position and velocity of an occupant to be accurately known and, when used with an appropriate pattern recognition system, it is capable of positively determining the presence of a rear facing child seat. One pattern recognition system which has been used to identify a rear facing child seat uses neural networks and is similar to that described in the above referenced papers by Gorman et al.

A focusing system, such as used on some camera systems, could be used to determine the initial position of an occupant but is too slow to monitor his position during a crash. This is a result of the mechanical motions required to operate the lens focusing system. By itself it cannot determine the presence of a rear facing child seat or of an occupant but when used with a charge-coupled device plus some infrared illumination for night vision, and an appropriate pattern recognition system, this becomes possible.

From the above discussion, it can be seen that the addition of sophisticated pattern recognition means to any of the standard illumination and/or reception technologies for use in a motor vehicle permits the development of a host of new products, systems or capabilities heretofore not available and as described in more detail below.

With respect to prior art related to the detection of child restraining seats, U.S. Pat. No. 5,605,348 (Blackburn et al.) describes method and apparatus for sensing a rearward facing child restraining seat in which a child restraining seat identification tag is secured to the child restraining seat and an antenna coil is energized to transmit an EMF field. The tag is made of an amorphous material that radiates a return EMF signal that is received by the antenna coil. The system determines whether a rear-facing child seat is present based on the presence of the return EMF signal, which is received only if the tag mounted to bottom front of the child seat is within a certain distance from the antenna coil mounted in the back portion of the seat. Drawbacks of the system of Blackburn et al. are that a special tag must be incorporated into the child seat in order to detect the same, the system cannot differentiate between other similarly tagged objects and the system relies on the proper placement of the tag on the child seat. In other words, if the tag were to be improperly placed on the child seat, then the system would not accurately determine the presence and orientation of the same. Also, the system of Blackburn et al. does not generate, e.g., via the antenna coil, a signal based on the contents of the seat which is different depending on the contents of the seat, i.e., the signal for an adult occupant is different from the signal for a forward-facing child seat which is different from the signal for a rear-facing child seat, etc., and analyze the same in order to determine whether the contents of the seat include a child seat in a rear-facing position. Rather, the EMF field generated by the tag is the same signal, and only the power output is varied. Thus, either no signal (no EMF field) will be generated representing the absence of a rear-facing child seat or a signal (an EMF field) will be generated representing the presence of a rear-facing child seat.

This invention is a system to sense the presence, position and type of an occupying item such as an adult occupant and a child seat in a passenger compartment of a motor vehicle and more particularly, to identify and monitor the occupying items and their parts and other objects in the passenger compartment of a motor vehicle, such as an automobile or truck, by processing one or more signals received from the occupying items and their parts and other objects using one or more of a variety of pattern recognition techniques and illumination technologies. The received signal(s) may be a reflection of a transmitted signal, the reflection of some natural signal within the vehicle, or may be some signal emitted naturally by the object. Information obtained by the identification and monitoring system is then used to affect the operation of some other system in the vehicle.

The principle objects and advantages are (in no particular order):

1. To recognize the presence of a human on a particular seat of a motor vehicle and to use this information to affect the operation of another vehicle system such as the airbag system, heating and air conditioning system, or entertainment system, among others.

2. To recognize the presence of a human on a particular seat of a motor vehicle and then to determine his/her position and to use this position information to affect the operation of another vehicle system.

3. To recognize the presence of a human on a particular seat of a motor vehicle and then to determine his/her velocity relative to the passenger compartment and to use this velocity information to affect the operation of another vehicle system.

4. To determine the position of a seat in the vehicle using sensors remote from the seat and to use that information in conjunction with a memory system and appropriate actuators to position the seat to a predetermined location.

5. To determine the position, velocity or size of an occupant in a motor vehicle and to utilize this information to control the rate of gas generation, or the amount of gas generated, by an airbag inflator system or to control the amount of gas flowing into or out of the airbag.

6. To determine the fact that an occupant is not restrained by a seatbelt and therefore to modify the characteristics of the airbag system. This determination can be done either by monitoring the position of the occupant or through the use of a resonating device or reflector placed on the shoulder belt portion of the seatbelt.

7. To determine the presence or position of rear seated occupants in the vehicle and to use this information to affect the operation of a rear seat protection airbag for frontal impacts.

8. To determine the presence or position of occupants relative to the side impact airbag systems and to use this information to affect the operation of a side impact protection airbag system.

9. To determine the openness of a vehicle window and to use that information to affect another vehicle system.

10. To determine the presence of an occupant's hand or other object in the path of a closing window and to affect the window closing system.

11. To remotely determine the fact that a vehicle door is not tightly closed using an illumination transmitting and receiving system such as one employing electromagnetic or acoustic waves.

12. To determine the position of the shoulder of a vehicle occupant and to use that information to control the seatbelt anchorage point.

13. To determine the position of the rear of an occupant's head and to use that information to control the position of the headrest.

14. To recognize the presence of a rear facing child seat on a particular seat of a motor vehicle and to use this information to affect the operation of another vehicle system such as the airbag system.

15. To detect the presence of a child seat in a rear-facing position on a particular seat of a motor vehicle without requiring modifications of the child seat and to use this information to affect the operation of another vehicle system such as the airbag system.

16. To determine the total number of occupants of a vehicle and in the event of an accident to transmit that information, as well as other information such as the condition of the occupants, to a receiver remote from the vehicle.

17. To affect the vehicle entertainment system based on a determination of the size or location of various occupants or other objects within the vehicle passenger compartment.

18. To affect the vehicle heating, ventilation and air conditioning system based on a determination of the number, size and location of various occupants or other objects within the vehicle passenger compartment.

19. To determine the temperature of an occupant based on infrared radiation coming from that occupant and to use that information to control the heating, ventilation and air conditioning system.

20. To provide a vehicle interior monitoring system for determining the location of occupants within the vehicle and to include within the same system various electronics for controlling an airbag system.

21. To determine the approximate location of the eyes of a driver and to use that information to control the position of the rear view mirrors of the vehicle.

22. To monitor the position of the head of the vehicle driver and determine whether the driver is falling asleep or otherwise impaired and likely to lose control of the vehicle and to use that information to affect another vehicle system.

23. To monitor the position of the eyelids of the vehicle driver and determine whether the driver is falling asleep or otherwise impaired and likely to lose control of the vehicle and to use that information to affect another vehicle system.

24. To determine the location of the eyes of a vehicle occupant and the direction of a light source such as the headlights of an oncoming vehicle or the sun and to cause a filter to be placed in such a manner as to reduce the intensity of the light striking the eyes of the occupant.

25. To determine the location of the eyes of a vehicle occupant and the direction of a light source such as the headlights of a rear approaching vehicle or the sun and to cause a filter to be placed in such a manner as to reduce the intensity of the light reflected from the rear view mirrors and striking the eyes of the occupant.

26. To determine the location of the ears of a vehicle occupant and to use that information to control the entertainment system so as to improve the quality of the sound reaching the occupant's ears through such methods as noise canceling sound.

27. To recognize a particular driver based on such factors as physical appearance or other attributes and to use this information to control another vehicle system such as a security system, seat adjustment, or maximum permitted vehicle velocity, among others.

These and other objects and advantages will become apparent from the following description of the preferred embodiments of the vehicle interior identification and monitoring system of this invention.

In one embodiment, a detector system for detecting the presence of the child seat on the seat comprises receiving means arranged in the vehicle for obtaining information about contents of the seat and generating a signal based on any contents of the seat. The receiving means generate a different signal for different contents of the seat when such contents are present on the seat, i.e., a different signal will be generated for an adult occupant then for a child seat. The system also includes analyzing means coupled to the receiving means for analyzing the signal in order to determine whether the contents of the seat include a child seat, and may also determine the orientation of the child seat, i.e., whether it is forward-facing or rear-facing. The receiving means may comprise wave transmitting means for transmitting waves, e.g., ultrasonic waves, toward the seat, wave receiving means arranged relative to the wave transmitting means for receiving waves reflected from the seat and a processor coupled to the wave receiving means for generating the different signal for the different contents of the seat based on the received waves reflected from the seat.

In one embodiment wherein there are two wave receivers spaced apart from one another, the processor processes the reflected waves from each receiver in order to create a respective signal characteristic of the contents of the seat based on the reflected waves. The analyzing means may therefore comprise categorization means coupled to the processor for categorizing the signals and which categorization means comprise pattern recognition means, e.g., a trained neural network, for recognizing and thus identifying the contents of the seat by processing the signals based on the reflected waves from the contents of the seat into a categorization of the signals characteristic of the contents of the seat. Each signal may comprise a plurality of data, all of which is compared to the data corresponding to patterns of reflected waves stored within the pattern recognition means and associated with possible contents of the seat.

The method for detecting the presence of a child seat on the seat comprises the steps of obtaining information about contents of the seat, generating a signal based on the information about the contents of the seat, a different signal being generated for different contents of the seat when such contents are present on the seat, and analyzing the signal in order to determine whether the contents of the seat include a child seat. Other features of the method include those described immediately above.

In another disclosed embodiment for controlling a system in the vehicle based on the occupying item, at least a portion of the passenger compartment in which the occupying item is situated is irradiated, reflected radiation from surfaces of the occupying item are received, e.g., by a plurality of sensors or transducers each arranged at a discrete location, the received radiation is processed by a processor in order to create at least one electronic signal characteristic of the occupying item based on the received radiation, each signal containing a pattern representative and/or characteristic of the occupying item and each signal is then categorized by utilizing pattern recognition means for recognizing and thus identifying the class of the occupying item. The pattern recognition means process each signal into a categorization thereof based on data corresponding to patterns of received radiation stored within the pattern recognition means and associated with possible classes of occupying items of the vehicle. Once the signal(s) is/are categorized, the operation of the system in the vehicle may be affected based on the categorization of the signal(s), and thus based on the occupying item.

If the system in the vehicle is a vehicle communication system, then an output representative of the number of occupants in the vehicle may be produced based on the categorization of the signal(s) and the vehicle communication system thus controlled based on such output. Similarly, if the system in the vehicle is a vehicle entertainment system or heating and air conditioning system, then an output representative of specific seat occupancy may be produced based on the categorization of the signal(s) and the vehicle entertainment or heating and air conditioning system thus controlled based on such output.

In one embodiment designed to ensure safe operation of the vehicle, the attentiveness of the occupying item is determined from the signal(s) if the occupying item is an occupant, and in addition to affecting the system in the vehicle based on the categorization of the signal, the system in the vehicle is affected based on the determined attentiveness of the occupant.

One embodiment of the interior monitoring system in accordance with the invention comprises means for irradiating at least a portion of the passenger compartment in which an occupying item is situated, receiver means for receiving reflected radiation from the occupying item, e.g., a plurality of receivers, each arranged at a discrete location, processor means coupled to the receivers for processing the received radiation from each receiver in order to create a respective electronic signal characteristic of the occupying item based on the received radiation, each signal containing a pattern representative of the occupying item, categorization means coupled to the processor means for categorizing the signals, and output means coupled to the categorization means for affecting at least one other system within the vehicle based on the categorization of the signals characteristic of the occupying item. The categorization means may comprise pattern recognition means for recognizing and thus identifying the class of the occupying item by processing the signals into a categorization thereof based on data corresponding to patterns of received radiation stored within the pattern recognition means and associated with possible classes of occupying items of the vehicle. Each signal may comprises a plurality of data, all of which is compared to the data corresponding to patterns of received radiation stored within the pattern recognition means and associated with possible classes of contents of the vehicle.

In one specific embodiment, the system includes location determining means coupled to the processor means for determining the location of the occupying item, e.g., based on the received radiation such that the output means which are coupled to the location determining means, in addition to affecting the other system based on the categorization of the signals characteristic of the occupying item, affect the system based on the determined location of the occupying item.

In another embodiment to determine the presence or absence of an occupant, the categorization means comprise pattern recognition means for recognizing the presence or absence of an occupying item in the passenger compartment by processing each signal into a categorization thereof signal based on data corresponding to patterns of received radiation stored within the pattern recognition means and associated with possible occupying items of the vehicle and the absence of such occupying items.

The invention will be described with reference to the following non-limiting drawings.

FIG. 1 is a side view with parts cutaway and removed of a vehicle showing the passenger compartment containing a rear facing child seat on the front passenger seat and a preferred mounting location for an occupant and rear facing child seat presence detector.

FIG. 1A is a side view with parts cutaway and removed of a vehicle showing the passenger compartment containing a rear facing child seat on the front passenger seat having a resonator or reflector placed onto the forward most portion of the child seat.

FIG. 2 is a side view with parts cutaway and removed showing schematically the interface between the vehicle interior monitoring system of this invention and the vehicle cellular communication system.

FIG. 3 is a side view with parts cutaway and removed showing schematically the interface between the vehicle interior monitoring system of this invention and the vehicle heating and air conditioning system.

FIG. 4 is a side view with parts cutaway and removed showing schematically the interface between the vehicle interior monitoring system of this invention and the vehicle airbag system.

FIG. 5 is a side view with parts cutaway and removed showing schematically the interface between the vehicle interior monitoring system of this invention and the vehicle entertainment system.

FIG. 6 is a side view with parts cutaway and removed of a vehicle showing the passenger compartment containing a driver and a preferred mounting location for an occupant identification system.

FIG. 7A is a functional block diagram of the ultrasonic imaging system illustrated in FIG. 1 using a microprocessor.

FIG. 7B is a functional block diagram of the ultrasonic imaging system illustrated in FIG. 1 using an application specific integrated circuit (ASIC).

FIG. 8 is a side view with parts cutaway and removed of a vehicle showing the passenger compartment containing a box on the front passenger seat and a preferred mounting location for an occupant and rear facing child seat presence detector.

FIG. 9 is a side view with parts cutaway and removed of a vehicle showing the passenger compartment containing a driver and a preferred mounting location for an occupant position sensor for use in side impacts and also of a rear of occupant's head locator for use with a headrest adjustment system to reduce whiplash injuries in rear impact crashes.

FIG. 10 is a side view with parts cutaway and removed of a vehicle showing the passenger compartment containing a front passenger and a preferred mounting location for an occupant head detector and a preferred mounting location of an adjustable microphone and speakers.

FIG. 11 is a side view with parts cutaway and removed of a subject vehicle and an oncoming vehicle, showing the headlights of the oncoming vehicle and the passenger compartment of the subject vehicle, containing detectors of the driver's eyes and detectors for the headlights of the oncoming vehicle and the selective filtering of the light of the approaching vehicle's headlights through the use of electro-chromic glass in the windshield.

FIG. 11A is an enlarged view of the section designated 11A in FIG. 11.

FIG. 12 is a side view with parts cutaway and removed of a vehicle and a following vehicle showing the headlights of the following vehicle and the passenger compartment of the leading vehicle containing a driver and a preferred mounting location for driver eyes and following vehicle headlight detectors and the selective filtering of the light of the following vehicle's headlights through the use of electro-chromic glass in the rear view mirror.

FIG. 12A is an enlarged view of the section designated 12A in FIG. 12.

FIG. 13 is a side view with parts cutaway and removed of a vehicle showing the passenger compartment containing a driver, a shoulder height sensor and a seatbelt anchorage adjustment system.

FIG. 14 is a side view with parts cutaway and removed of a seat in the passenger compartment of a vehicle showing the use of ultrasonic resonators or reflectors to determine the position of the seat.

FIG. 15 is a side view with parts cutaway and removed of the passenger compartment of a vehicle showing the use of ultrasonic resonators or reflectors to determine the position of the driver seatbelt.

FIG. 16 is a side view with parts cutaway and removed of the passenger compartment of a vehicle showing the use of an ultrasonic resonator or reflector to determine the extent of opening of the driver window and of a system for determining the presence of an object, such as the hand of an occupant, in the window opening.

FIG. 16A is a side view with parts cutaway and removed of the passenger compartment of a vehicle showing the use of an ultrasonic resonator or reflector to determine the extent of opening of the driver window and of another system for determining the presence of an object, such as the hand of an occupant, in the window opening.

FIG. 17 is a side view with parts cutaway and removed of the passenger compartment of a vehicle showing the use of an ultrasonic resonator or reflector to determine the extent of opening of the driver side door.

FIG. 18 is a side view with parts cutaway and removed showing schematically the interface between the vehicle interior monitoring system of this invention and the vehicle security system.

FIG. 19 is a side view with parts cutaway and removed showing schematically the interface between the vehicle interior monitoring system of this invention and an instrument panel mounted inattentiveness warning light or buzzer and reset button.

Referring to the accompanying drawings wherein the same reference numerals refer to the same or similar elements, in FIG. 1 a side view, with parts cutaway and removed, of a vehicle showing the passenger compartment containing a rear facing child seat 110 on a front passenger seat 120 and a preferred mounting location for an occupant and child seat presence detector in accordance with the invention is illustrated. In this implementation, three ultrasonic transducers 131, 132 and 133 are used in the presence detector in accordance with the invention, although any number of wave-transmitting transducers or radiation-receiving receivers may be used. Such transducers or receivers may be of the type which emit or receive a continuous signal, a time varying signal or a spacial varying signal such as in a scanning system. Transducer 132 transmits ultrasonic energy toward the front passenger seat, which is reflected, in this case by the occupying item of the passenger seat, i.e., the rear facing child seat 110, and the reflected waves are received by the transducers 131 and 133. The waves received by transducers 131 and 133 vary with time depending on the shape of the object occupying the passenger seat, in this case the rear facing child seat 110. Each object will reflect back a signal having a different pattern. Also, the pattern received by transducer 131 will differ slightly from the pattern received by transducer 133 in view of its different mounting location. In some systems, this difference permits the determination of location of the reflecting surface through triangulation. Through the use of two transducers 131,133, a sort of stereographic image is received by the two transducers and recorded for analysis by processor 101, which is coupled to the transducers 131,132,133. This image will differ for each object that is placed on the vehicle seat and it will also change for each position of a particular object and for each position of the vehicle seat.

The "image" recorded from each ultrasonic transducer/receiver, for ultrasonic systems, is actually a time series of digitized data of the amplitude of the received signal versus time. Since there are two receivers, two time series are obtained which are processed by the processor 101. When different objects are placed on the front passenger seat the two images are different but there are also similarities between all images of rear facing child seats, for example, regardless of where on the vehicle seat it is placed and regardless of what company manufactured the child seat. Alternately, there will be similarities between all images of people sitting on the seat regardless of what they are wearing, their age or size. The problem is to find the "rules" which differentiate the occupant images from the rear facing child seat images. The similarities of these images for various child seats are frequently not obvious to a person looking at plots of the time series and thus computer algorithms are developed to sort out the various patterns.

The determination of these rules is central to the pattern recognition techniques used in this invention. In general, three approaches have been useful, artificial intelligence, fuzzy logic and artificial neural networks. In some implementations of this invention, such as the determination that there is an object in the path of a closing window as described below, the rules are sufficiently obvious that a trained researcher can look at the returned acoustic signals and devise a simple algorithm to make the required determinations. In others, such as the determination of the presence of a rear facing child seat or of an occupant, artificial neural networks are used to determine the rules. One such set of neural network software for determining the pattern recognition rules is available from the NeuralWare Corporation of Pittsburgh, Pa.

The system used in a preferred implementation of this invention for the determination of the presence of a rear facing child seat, of an occupant or of an empty seat was the artificial neural network. In this case, the network operates on the two returned signals as sensed by transducers 131 and 133. Through a training session, the system is taught to differentiate between the three cases. This is done by conducting a large number of experiments where all possible child seats are placed in all possible orientations on the front passenger seat. Similarly a sufficiently large number of experiments are run with human occupants and with boxes, bags of groceries and other objects. Sometimes as many as 1,000,000 such experiments are run before the neural network is sufficiently trained so that it can differentiate among the three cases and output the correct decision with a very high probability.

Once the network is determined, it is possible to examine the result using tools supplied by NeuralWare, for example, to determine the rules that were finally arrived at by the trial and error techniques. In that case, the rules can then be programmed into a microprocessor resulting in a fuzzy logic or other rule based system. Alternately, a neural computer can be used to implement the net directly. In either case, the implementation can be carried out by those skilled in the art of pattern recognition. If a microprocessor is used, a memory device is also required to store the data from the analog to digital converters that digitize the data from the receiving transducers. On the other hand, if a neural network computer is used, the analog signal can be fed directly from the transducers to the neural network input nodes and an intermediate memory is not required. Memory of some type is needed to store the computer programs in the case of the microprocessor system and if the neural computer is used for more than one task, a memory is needed to store the network specific values associated with each task.

An alternate system is shown in FIG. 2, which is a side view showing schematically the interface between the vehicle interior monitoring system of this invention and the vehicle cellular communication system. In this view, an adult occupant 210 is shown sitting on the front passenger seat 220 and two ultrasonic transducers 231 and 232 are used to determine the presence (or absence) of the occupant on that seat 220. One of the transducers 232 in this case acts as both a transmitter and receiver while transducer 231 acts only as a receiver. Alternately, transducer 231 could serve as both a transmitter and receiver or the transmitting function could be alternated between the two devices. Also, in many cases more that two transmitters and receivers are used and in still other cases other types of sensors, such as weight, seatbelt buckle, seatbelt payout and seat and seatback position sensors, are also used in combination with the radiation sensors. As was also the case in FIG. 1, the transducers 231 and 232 are attached to the vehicle buried in the A-pillar trim, where their presence is disguised, and are connected to processor 101 that is also hidden in the trim. The A-pillar is the roof support pillar that is closest to the front of the vehicle and which, in addition to supporting the roof, also supports the front windshield and the front door. Naturally, other mounting locations can also be used.

The interface between the monitoring system and the cellular phone system is shown schematically by box 240 that outputs to an antenna 250A. The transducers 231 and 232 in conjunction with the pattern recognition hardware and software, which is implemented in processor 101 and is packaged on a printed circuit board or flex circuit along with the transducers 231 and 232, determine the presence of an occupant within a few seconds after the vehicle is started. Similar systems located to monitor the remaining seats in the vehicle, also determine the presence of occupants at the other seating locations and this result is stored in the computer memory which is part of each monitoring system processor 101. In the event of an accident, the electronic system associated with the cellular phone system interrogates the various interior monitoring system memories and arrives at a count of the number of occupants in the vehicle, and in more sophisticated systems, even makes a determination as to whether each occupant was wearing a seatbelt and if he or she is moving after the accident. The phone system then automatically dials the EMS operator (such as 911) and the information obtained from the interior monitoring systems is forwarded so that a determination can be made as to the number of ambulances and other equipment to send to the accident site. Vehicles having this capability are now in service. Such vehicles also have a global positioning system, which permits the vehicle to determine its exact location and to forward this information to the EMS operator.

The control of the heating, ventilating, and air conditioning (HVAC) system alone would probably not justify the implementation of an interior monitoring system at least until the time comes when electronic heating and cooling systems replace the conventional systems now used. Nevertheless, if the monitoring system is present, it can be used to control the HVAC for a small increment in cost. The advantage of such a system is that since most vehicles contain only a single occupant, there is no need to direct heat or air conditioning to unoccupied seats. This permits the most rapid heating or cooling for the driver when the vehicle is first started and he is alone without heating or cooling unoccupied seats. Since the HVAC system does consume energy, an energy saving also results by only heating and cooling the driver when he is alone.

FIG. 3 shows a side view of a vehicle passenger compartment showing schematically an interface 260 between the vehicle interior monitoring system of this invention and the vehicle heating and air conditioning system. In addition to the transducers 231 and 232, which at least in this embodiment are preferably acoustic (ultrasonic) transducers, an infrared sensor 234 is also shown mounted in the A-pillar and which monitors the temperature of the occupant. The output from each of the transducers is fed into processor 101 that is in turn connected to interface 260. In this manner, the HVAC control is based on the occupant's temperature rather than that of the ambient air in the vehicle, as well as the determined presence of the occupant via transducers 231,232 as described above. This also permits each vehicle occupant to be independently monitored and the HVAC system to be adjusted for each occupant either based on a set temperature for all occupants or, alternately, each occupant could be permitted to set his own preferred temperature through adjusting a control knob shown schematically as 250 in FIG. 3. Since the monitoring system is already installed in the vehicle with its own associated electronics including processor 101, the infrared sensor can be added with little additional cost and can share the processing unit. Not only can this system be used for directing hot and cold air, but developments in the field of directing sound using hyper-sound now make it possible to accurately direct sound to the vicinity of the ears of an occupant so that only that occupant can hear the sound. The system of this invention can thus be used to find the proximate direction of the ears of the occupant for this purpose.

The use of the vehicle interior monitoring system to control the deployment of an airbag is discussed in detail in U.S. Pat. No. 5,653,462 cross referenced above. In that case, the control is based on the use of a simple pattern recognition system to differentiate between the occupant and his extremities in order to provide an accurate determination of the position of the occupant relative to the airbag. If the occupant is sufficiently close to the airbag module that he is more likely to be injured by the deployment itself than by the accident, the deployment of the airbag is suppressed. This process is carried further by the interior monitoring system described herein in that the nature or identity of the object occupying the vehicle seat is used to contribute to the airbag deployment decision. FIG. 4 shows a side view illustrating schematically the interface between the vehicle interior monitoring system of this invention and the vehicle airbag system 270.

In this embodiment, an ultrasonic transducer 232 transmits a burst of ultrasonic waves that travel to the occupant where they are reflected back to transducers or receptors/receivers 231 and 232. The time period required for the waves to travel from the generator and return is used to determine the distance from the occupant to the airbag as described in the aforementioned U.S. Pat. No. 5,653,462, i.e., and thus may also be used to determine the position or location of the occupant. In the case of this invention, however, the portion of the return signal, which represents the occupants' head or chest, has been determined based on pattern recognition techniques such as a neural network. The relative velocity of the occupant toward the airbag can then be determined, from successive position measurements, which permits a sufficiently accurate prediction of the time when the occupant would become proximate to the airbag. By comparing the occupant relative velocity to the integral of the crash deceleration pulse, a determination as to whether the occupant is being restrained by a seatbelt can also be made which then can affect the airbag deployment initiation decision. Alternately, the mere knowledge that the occupant has moved a distance which would not be possible if he were wearing a seatbelt gives information that he is not wearing one.

A more detailed discussion of this process and of the advantages of the various technologies, such as acoustic or electromagnetic, can be found in SAE paper 940527, "Vehicle Occupant Position Sensing" by Breed et al, which is included herein by reference. In this paper, it is demonstrated that the time delay required for acoustic waves to travel to the occupant and return does not prevent the use of acoustics for position measurement of occupants during the crash event. For position measurement and for many pattern recognition applications, ultrasonics is the preferred technology due to the lack of adverse health effects and the low cost of ultrasonic systems compared with either laser or radar. The main limiting feature of ultrasonics is the wavelength, which places a limitation on the size of features that can be discerned. Optical systems, for example, are required when the identification of particular individuals is required.

It is well known among acoustics engineers that the quality of sound coming from an entertainment system can be substantially affected by the characteristics and contents of the space in which it operates and the surfaces surrounding that space. When an engineer is designing a system for an automobile he has a great deal of knowledge about that space and of the vehicle surfaces surrounding it. He has little knowledge of how many occupants are likely to be in the vehicle on a particular day, however, and therefore the system is a compromise. If the system knew the number and position of the vehicle occupants, and maybe even their size, then adjustments could be made in the system output and the sound quality improved. FIG. 5, therefore, illustrates schematically the interface between the vehicle interior monitoring system of this invention, i.e., transducers 231,232 and processor 101 which operate as set forth above, and the vehicle entertainment system 280. The particular design of the entertainment system that uses the information provided by the monitoring system can be determined by those skilled in the appropriate art. Perhaps in combination with this system, the quality of the sound system can be measured by the audio system itself either by using the speakers as receiving units also or through the use of special microphones. The quality of the sound can then be adjusted according to the vehicle occupancy and the reflectivity of the vehicle occupants. If, for example, certain frequencies are being reflected more that others, the audio amplifier can be adjusted to amplify those frequencies to a lesser amount that others.

The maximum acoustic frequency that is practical to use for acoustic imaging in the systems is about 40 to 160 kilohertz (kHz). The wavelength of a 50 kHz acoustic wave is about 0.6 cm which is too coarse to determine the fine features of a person's face, for example. It is well understood by those skilled in the art that features which are smaller than the wavelength of the illuminating radiation cannot be distinguished. Similarly the wave length of common radar systems varies from about 0.9 cm (for 33,000 MHz K band) to 133 cm (for 225 MHz P band) which is also too coarse for person identification systems. In FIG. 6, therefore, the ultrasonic transducers of the previous designs are replaced by laser transducers 231 and 232 which are connected to a microprocessor 101. In all other manners, the system operates the same. The design of the electronic circuits for this laser system is described in some detail in the U.S. Pat. No. 5,653,462 cross-referenced above and in particular FIG. 8 thereof and the corresponding description. In this case, a pattern recognition system such as a neural network system is employed and uses the demodulated signals from the receptors 231 and 232.

The output of processor 101 of the monitoring system is shown connected schematically to a general interface 290 which can be the vehicle ignition enabling system; the entertainment system; the seat, mirror, suspension or other adjustment systems; or any other appropriate vehicle system.

There are two preferred methods of implementing the vehicle interior monitoring system of this invention, a microprocessor system and an application specific integrated circuit system (ASIC) (or equivalently a "system on an chip" using today's technology). Both of these systems are represented schematically as either 101 or 601 herein. A block diagram illustrating the microprocessor system is shown in FIG. 7A which shows the implementation of the system of FIG. 1. An alternate implementation of the FIG. 1 system using an ASIC is shown in FIG. 7B. In both cases the target, which may be a rear facing child seat, is shown schematically as 10 and the three transducers as 131, 132, and 133. In the embodiment of FIG. 7A, there is a digitizer coupled to the receivers 131,133 and the processor, and an indicator coupled to the processor. In the embodiment of FIG. 7B, there is a memory unit associated with the ASIC and also an indicator coupled to the ASIC.

In FIG. 8, a view of the system of FIG. 1 is illustrated with a box 295 shown on the front passenger seat in place of the rear facing child seat. The vehicle interior monitoring system of this invention is trained to recognize that this box 295 is neither a rear facing child seat nor an occupant and therefore it is treated as an empty seat and the deployment of the airbag is suppressed. This training is accomplished using a neural network with the commercially available software disclosed above and provided by NeuralWare of Pittsburgh. The system assesses the probability that the box is a person, however, and if there is even the remotest chance that it is a person, the airbag deployment is not suppressed. The system is thus typically biased toward airbag deployment.

Side impact airbags are now beginning to be used on some vehicles. These initial airbags are quite small compared to the driver or passenger airbags used for frontal impact protection. Nevertheless, a small child could be injured if he is sleeping with his head against the airbag when it deploys and a vehicle interior monitoring system is needed to prevent such a deployment in that event. In FIG. 9, a single ultrasonic transducer 330 is shown mounted in the vehicle door adjacent to the airbag system. This device is not used to identify the object that is adjacent the airbag but merely to measure the position of the object.

A rear-of-head detector 334 is also illustrated in FIG. 9. This detector 334 is used to determine the distance from the headrest to the rear most position of the occupant's head and to therefore control the position of the headrest so that it is properly positioned behind the occupant's head to offer optimum support in the event of a rear impact. Although the headrest of most vehicles is adjustable, it is rare for an occupant to position it properly if at all. Each year there are in excess of 400,000 whiplash injuries in vehicle impacts approximately 90,000 of which are from rear impacts (source: National Highway Traffic Safety Administration, (NHTSA)). A properly positioned headrest could substantially reduce the frequency of such injuries, which can be accomplished by the head detector of this invention. The head detector 334 is shown connected schematically to the headrest control mechanism and circuitry 340. This mechanism is capable of moving the headrest up and down and, in some cases, rotating it fore and aft.

When the driver of a vehicle is using a cellular phone, the phone microphone frequently picks up other noise in the vehicle making it difficult for the other party to hear what is being said. This noise can be reduced if a directional microphone is used and directed toward the mouth of the driver. This is difficult to do since position of drivers' mouths varies significantly depending on such things as the size and seating position of the driver. By using the vehicle interior identification and monitoring system of this invention, and through appropriate pattern recognition techniques, the location of the driver's head can be determined with sufficient accuracy even with ultrasonics to permit a directional microphone having a 15 degree cone angle to be aimed at the mouth of the driver resulting in a clear reception of his voice. The use of directional speakers in a similar maimer also improves the telephone system performance. Such a system can also be used to permit effortless conversations between occupants of the front and rear seats. Such a system is shown in FIG. 10 which is a system similar to that of FIG. 2 only using three ultrasonic transducers 231, 232 and 233 to determine the location of the driver's head and control the pointing direction of a microphone 355. Speaker 357 is shown connected schematically to the phone system 359 completing the system.

The transducers 231 and 232 are placed high in the A-pillar and the third transducer 233 is placed in the headliner and displaced horizontally from transducers 231 and 232. The two transducers 231 and 232 provide information to permit the determination of the locus of the head in the vertical direction and the combination of one of transducers 231 and 232 in conjunction with transducer 233 is used to determine the horizontal location of the head. The three transducers are placed high in the vehicle passenger compartment so that the first returned signal is from the head. Temporal filtering is used to eliminate signals which are reflections from beyond the head and the determination of the head center location is then found by the approximate centroid of the head returned signal. That is, once the location of the return signal centroid is found from each of the three received signals from transducers 231, 232 and 233, the distance to that point is known for each of the transducers based on the time it takes the signal to travel from the head to each transducer. In this maimer, by using the three transducers plus an algorithm for finding the coordinates of the head center, using processor 101, and through the use of known relationships between the location of the mouth and the head center, an estimate of the mouth location, and the ear locations, can be easily determined within a circle having a diameter of about five inches (13 cm). This is sufficiently accurate for a directional microphone to cover the mouth while excluding the majority of unwanted noise.

The headlights of oncoming vehicles frequently make it difficult for the driver of a vehicle to see the road and safely operate the vehicle. This is a significant cause of accidents and much discomfort. The problem is especially severe during bad weather where rain can cause multiple reflections. Visors are now used to partially solve this problem but they do so by completely blocking the view through a large portion of the window and therefore cannot be used to cover the entire windshield. Similar problems happen when the sun is setting or rising and the driver is operating the vehicle in the direction of the sun. The vehicle interior monitoring system of this invention can contribute to the solution of this problem by determining the position of the driver's eyes. If separate sensors are used to sense the direction of the light from the on-coming vehicle or the sun, and through the use of electro-chromic glass or a liquid crystal film for example, a portion of the windshield can be darkened to impose a filter between the eyes of the driver and the light source. Electro-chromic glass is a material where the color of the glass can be changed through the application of an electric current. By dividing the windshield into a controlled grid or matrix of contiguous areas and through feeding the current into the windshield from orthogonal directions, selective portions of the windshield can be darkened as desired. Other systems for selectively imposing a filter between the eyes of an occupant and the light source are currently under development.

FIG. 11 illustrates how such a system operates. A sensor 410 located on vehicle 402 determines the direction of the light 412 from the headlights of oncoming vehicle 404. Sensor 410 is comprised of a lens and a charge-coupled device (CCD), of CMOS light sensing or similar device, with appropriate electronic circuitry which determines which elements of the CCD are being most brightly illuminated. An algorithm stored in processor 101 then calculates the direction of the light from the oncoming headlights based on the information from the CCD, or CMOS device. Transducers 231, 232 and 233 determine the probable location of the eyes of the operator 210 of vehicle 402 in a manner such as described above in conjunction with the determination of the location of the driver's mouth in the discussion of FIG. 10. In this case, however, the determination of the probable locus of the driver's eyes is made with an accuracy of a diameter for each eye of about 3 inches (7.5 cm). This calculation sometimes will be in error and provision is made for the driver to make an adjustment to correct for this error as described below.

The windshield 416 of vehicle 402 is made from electro-chromic glass or comprises a liquid crystal film or similar system, and is selectively darkened at area 418 due to the application of a current along perpendicular directions 422 and 424 of windshield 416 or other appropriate means. The particular portion of the windshield to be darkened is determined by processor 101. Once the direction of the light from the oncoming vehicle is known and the locations of the driver's eyes are known, it is a matter of simple trigonometry to determine which areas of the windshield matrix should be darkened to impose a filter between the headlights and the driver's eyes. This is accomplished by processor 101. A separate control system, not shown, located on the instrument panel, or at some other convenient location, allows the driver to select the amount of darkening accomplished by the system from no darkening to maximum darkening. In this manner, the driver can select the amount of light that is filtered to suit his particular physiology. The sensor 410 can either be designed to respond to a single light source or to multiple light sources to be sensed and thus multiple portions of the vehicle windshield to be darkened.

As mentioned above, the calculations of the location of the driver's eyes using acoustic systems may be in error and therefore provision must be made to correct for this error. One such system permits the driver to adjust the center of the darkened portion of the windshield to correct for such errors through a knob on the instrument panel, steering wheel or other convenient location. Another solution permits the driver to make the adjustment by slightly moving his head. Once a calculation as to the location of the driver's eyes has been made, that calculation is not changed even though the driver moves his head slightly. It is assumed that the driver will only move his head to center the darkened portion of the windshield to optimally filter the light from the oncoming vehicle. The monitoring system will detect this initial head motion and make the correction automatically for future calculations.

Electro-chromic glass is currently used in rear view mirrors to darken the entire mirror in response to the amount of light striking an associated sensor. This substantially reduces the ability of the driver to see objects coming from behind his vehicle. If one rear-approaching vehicle, for example, has failed to dim his lights, the mirror will be darkened to respond to the light from that vehicle making it difficult for the driver to see other vehicles that are also approaching from the rear. If the rear view mirror is selectively darkened on only those portions which cover the lights from the offending vehicle, the driver is able to see all of the light coming from the rear whether the source is bright or dim. This permits the driver to see all of the approaching vehicles not just the one with bright lights.

Such a system is illustrated in FIG. 12 where rear view mirror 460 is equipped with electro-chromic glass, or comprises a liquid crystal film, having the capability of being selectively darkened, e.g., at area 419. Associated with mirror 460 is a light sensor 462 that determines the direction of light 412 from the headlights of rear approaching vehicle 405. In the same manner as above, transducers 231, 232 and 233 determine the location of the eyes of the driver 210. The signals from both sensor systems, 231, 232 plus 233 and 462, are combined in processor 101, where a determination is made as to what portions of the mirror should be darkened, e.g., area 419. Appropriate currents are then sent to the mirror in a manner similar to the windshield system described above.

Seatbelts are most effective when the upper attachment point to the vehicle is positioned vertically close to the shoulder of the occupant being restrained. If the attachment point is too low the occupant experiences discomfort from the rubbing of the belt on his shoulder. If it is too high, the occupant may experience discomfort due to the rubbing of the belt against his neck and the occupant will move forward by a greater amount during a crash which may result in his head striking the steering wheel. Women in particular experience discomfort from an improperly adjusted seatbelt anchorage point. For these reasons, it is desirable to have the upper seatbelt attachment point located slightly above the occupant's shoulder. To accomplish this for various sized occupants, the location of the occupant's shoulder must be known which can be accomplished by the vehicle interior monitoring system described herein. Such a system is illustrated in FIG. 13 that is a side view of a seatbelt anchorage adjustment system. In this system, a transmitter and receiver (transducer) 520 is positioned in a convenient location, such as the headliner, located above and to the outside of the occupant's shoulder. A narrow elliptical beam 521 of energy is transmitted from transducer 520 in a manner such that it illuminates the occupant's shoulder and headrest. An appropriate pattern recognition system as described above is then used to determine the location and position of the shoulder. This information is fed to the seatbelt anchorage height adjustment system 528, shown schematically, which moves the attachment point 529 to the optimum vertical location.

Acoustic resonators are devices that resonate at a preset frequency when excited at that frequency. If such a device, which has been tuned to 40 kHz, is subjected to ultrasonic radiation at 40 kHz, for example, it will return a signal that is much stronger than the reflected radiation. If such a device is placed at a particular point in the passenger compartment of a vehicle, the returned signal can be easily identified as a high magnitude narrow signal at a particular point in time which is proportional to the distance from the resonator to the receiver. Since this device can be easily identified, it provides a particularly effective method of determining the distance to a particular point in the vehicle passenger compartment. Alternately, a device having a highly reflecting surface can be used in place of a resonator. If several such resonators are reflectors are used they can be tuned to slightly different frequencies and therefore separated and identified by the circuitry. Using such resonators or reflectors the positions of various objects in the vehicle can be determined. In FIG. 14 for example, three such resonators or reflectors are placed on the vehicle seat and used to determine the location of the front and back of the seat and the top of the seat back. In this case, transducers 231 and 232, mounted in the A-pillar 662, are used in conjunction with resonators 641, 642 and 643 to determine the position of the seat. This information is then fed to the seat memory and adjustment system, not shown, eliminating the currently used sensors that are placed typically beneath the seat adjacent the seat adjustment motors. In the conventional system, the seat sensors must be wired into the seat adjustment system and are prone to being damaged. By using the vehicle interior monitoring system alone with inexpensive passive resonators or reflectors, the conventional seat sensors can be eliminated resulting in a cost saving to the vehicle manufacturer. An efficient reflector, such as a parabolic shaped reflector, can be used in a similar manner as the resonator.

Resonators or reflectors, of the type described above can be used for making a variety of position measurements in the vehicle. These resonators are made to resonate at a particular frequency. If the number of resonators increases beyond a reasonable number, dual frequency resonators can be used. A pair of frequencies is then used to identify a particular location. Alternately, resonators tuned to a particular frequency can be used in combination with special transmitters, which transmit at the tuned frequency, which are designed to work with a particular resonator or group of resonators. The cost of the transducers is sufficiently low to permit special transducers to be used for special purposes. The use of resonators which resonate at different frequencies requires that they be illuminated by radiation containing those frequencies.

Another application for a resonator of the type described is to determine the location of the seatbelt and therefore determine whether it is in use. If it is known that the occupants are wearing seatbelts, the airbag deployment threshold can be increased since the airbag is not needed in low velocity accidents if the occupants are already restrained by seatbelts. This will reduce the number of deployments for cases where the airbag provides little or no improvement in safety over the seatbelt. FIG. 15, for example, shows the placement of a resonator 602 onto the front surface of the seatbelt where it can be sensed by the transducers 231 and 232. Such a system can also be used to positively identify the presence of a rear facing child seat in the vehicle. In this case the resonator 603 is placed onto the forward most portion of the child seat, or in some other convenient position, as shown in FIG. 1A.

Other uses for such resonators include placing them on doors and windows in order to determine whether either is open or closed. In FIG. 16A, for example, such a resonator 604 is placed onto the top of the window and is sensed by transducers 611 and 612. In this case, transducers 611 and 612 also monitor the space between the edge of the window glass and the top of the window opening. Many vehicles now have systems which permit the rapid opening of the window, called "express open", by a momentary push of a button. For example, when a vehicle approaches a tollbooth, the driver needs only touch the window control button and the window opens rapidly. Some automobile manufacturers do not wish to use such systems for closing the window, called "express close", because of the fear that the hand of the driver, or of a child leaning forward from the rear seat, or some other object, could get caught between the window and window frame. If the space between the edge of the window and the window frame were monitored with an interior monitoring system, this problem can be solved. The presence of the resonator or reflector 604 on the top of the window glass also gives a positive indication of where the top surface is and reflections from below that point can be ignored.

Various design variations of the window monitoring system are possible and the particular choice will depend on the requirements of the vehicle manufacturer and the characteristics of the vehicle. Two systems will be briefly described here.

In the first example shown in FIG. 16, a single transmitter/receiver (transducer) 613 is used in place of and located centrally midway between the transducers 611 and 612 shown in FIG. 16A. A recording of the output of transducer 613 is made of the open window without an object in the space between the window edge and the top of the window frame. When in operation, the transducer 613 receives the return signal from the space it is monitoring and compares that signal with the stored signal referenced above. This is done by processor 601. If the difference between the test signal and the stored signal indicates that there is a reflecting object in the monitored space, the window is prevented from closing in the express close mode. If the window is part way up, a reflection will be received from the edge of the window glass which, in most cases, is easily identifiable from the reflection of a band for example. A simple algorithm based on the intensity of the reflection in most cases is sufficient to determine that an object rather than the window edge is in the monitored space. In other cases, the algorithm is used to identify the window edge and ignore that reflection and all other reflections which are lower (i.e. later in time) than the window edge. In all cases, the system will default in not permitting the express close if there is any doubt. The operator can still close the window by holding the switch in the window closing position and the window will then close slowly as it now does in vehicles without the express close feature.

In the second system, two transducers 611 and 612 are used as shown in FIG. 16A and the processor 601 comprises a neural network. In this example the system is trained for all cases where the window is down and at intermediate locations. In operation, the transducers monitor the window space and feed the received signals to processor 601. As long as the signals are similar to one of the signals for which the network was trained, the express close system is enabled. As before, the default is to suppress the express close.

The use of a resonator, or reflector, to determine whether the vehicle door is properly shut is illustrated in FIG. 17. In this case, the resonator 702 is placed in the B-pillar in such a manner that it is shielded by the door, or by a cover or other inhibiting mechanism (not shown) engaged by the door, and prevented from resonating when the door is closed. Resonator 702 provides waves 704. If transducers such as 231 and 232 in FIG. 3 are used in this system, the closed-door condition would be determined by the absence of a return signal from the B-pillar 702 resonator. This system permits the substitution of an inexpensive resonator for a more expensive and less reliable electrical switch.

The use of an acoustic resonator has been described above. For those cases where an infrared laser system is used, an optical mirror would replace the mechanical resonator used with the acoustic system. In the acoustic system, the resonator can be any of a variety of tuned resonating systems including an acoustic cavity or a vibrating mechanical element.

A neural network, or other pattern recognition system, can be trained to recognize certain people as permitted operators of a vehicle. In this case, if a non-recognized person attempts to operate the vehicle, the system can disable the vehicle and/or sound an alarm as illustrated in FIG. 18. In this figure the sensing transducers are shown as before as 231A, 232A and 233A, the alarm system schematically as 708 and the alarm as 705. Since it is unlikely that an unauthorized operator will resemble the authorized operator, the neural network system can be quite tolerant of differences in appearance of the operator. The system defaults to where a key must be used in the case that the system doesn't recognize the driver or the owner wishes to allow another person to operate the vehicle. The transducers 231A, 232A and 233A are sensitive to infrared radiation and the operator is illuminated with infrared waves from transducer 231A. This is necessary due to the small size of the features which need to be recognized for high accuracy of recognition. An alternate system uses an infrared laser, which can be 231A in FIG. 18, to illuminate the operator and a CCD device, which can be represented as 232A in FIG. 18, to receive the reflected image. In this case the recognition of the operator is accomplished using a pattern recognition system such as described in Popesco, V. and Vincent, J. M. "Location of Facial Features Using a Boltzmann Machine to Implement Geometric Constraints", Chapter 14 of Lisboa, P. J. G. and Taylor, M. J. Editors, Techniques and Applications of Neural Networks, Ellis Horwood Publishers, New York, 1993. In the present case a larger CCD element array containing 100,000 or more elements would in many cases be used instead of the 16 by 16 or 256 element CCD array used by Popesco and Vincent.

Once a vehicle interior monitoring system employing a sophisticated pattern recognition system, such as a neural network or fuzzy logic system, is in place, it is possible to monitor the motions of the driver over time and determine if he is falling asleep or has otherwise become incapacitated. In such an event, the vehicle can be caused to respond in a number of different ways. One such system is illustrated in FIG. 19 and consists of a monitoring system having transducers 231, 232 and 233 plus microprocessor 101, such as shown in FIG. 7A, programmed to compare the motions of the driver over time and trained to recognize changes in behavior representative of becoming incapacitated. If the system determines that there is a reasonable probability that the driver has fallen asleep, for example, then it can turn on a warning light shown here as 805 or send a warning sound. If the driver fails to respond to the warning by pushing a button 806, for example, then the horn and lights can be operated in a manner to warn other vehicles and the vehicle brought to a stop. One novel approach, not shown, would be to use the horn as the button 806. For a momentary depression of the horn, for this case, the horn would not sound. Naturally other responses can also be programmed.

An even more sophisticated system of monitoring the behavior of the driver is to track his eye motions using such techniques as are described in: Freidman et al, U.S. Pat. No. 4,648,052 "Eye Tracker Communication System"; Heyner et al, U.S. Pat. No. 4,720,189 "Eye Position Sensor"; Hutchinson U.S. Pat. No. 4,836,670 "Eye Movement Detector"; and, Hutchinson U.S. Pat. No. 4,950,069 "Eye Movement Detector With Improved Calibration and Speed", all of which are included herein by reference. The detection of the impaired driver in particular can be best determined by these techniques. Also, in a similar manner as described in these patents, the motion of the driver's eyes can be used to control various systems in the vehicle permitting hands off control of the entertainment system, heating and air conditioning system or all of the other systems described above. Although some of these systems have been described in the afore mentioned patents, none have made use of neural networks for interpreting the eye movements.

In most of the applications described above, a single frequency energy was used to illuminate various occupying items of the passenger compartment. This was for illustrative purposes only and this invention is not limited to single frequency illumination. In many applications, it is useful to use several discrete frequencies or a band of frequencies. In this manner considerably greater information is received from the reflected illumination permitting greater discrimination between different classes of objects. In general each object will have different reflectivities at each frequency. Also, the different resonators placed at different positions in the passenger compartment can now be tuned to different frequencies making it easier to isolate one resonator from another.

Although several preferred embodiments are illustrated and described above, there are possible combinations using other geometries, sensors, materials and different dimensions for the components that perform the same functions. This invention is not limited to the above embodiments and should be determined by the following claims.