# Patent

## Title
Techniques for improving safe operation of a vehicle

## Abstract

Vehicle control system and method in which restrictions on travel of the vehicle are determined based on an indication of the visibility of a driver and information about objects moving in a direction opposite to the direction of travel of the vehicle are considered. The travel restrictions include preventing a passing maneuver on a two-lane road when an oncoming vehicle precludes safely initiating or completing an already-initiated passing maneuver. A warning system is provided to warn a driver about the travel restrictions so that the driver will, hopefully, not attempt an unsafe maneuver.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 13/896,814 filed May 17, 2013, now U.S. Pat. No. 8,583,329, which is a continuation-in-part of U.S. patent application Ser. No. 12/613,071 filed Nov. 5, 2009, now U.S. Pat. No. 8,447,474, which is a divisional of U.S. patent application Ser. No. 11/926,192 filed Oct. 29, 2007, now U.S. Pat. No. 8,041,483, which is:
1. a continuation-in-part (CIP) of U.S. patent application Ser. No. 11/183,598 filed Jul. 18, 2005, now U.S. Pat. No. 7,359,782, which is a CIP of U.S. patent application Ser. No. 11/111,474 filed Apr. 21, 2005, now U.S. Pat. No. 7,209,221; and
2. a CIP of U.S. patent application Ser. No. 11/874,275 filed Oct. 22, 2007, now U.S. Pat. No. 7,783,403; and
3. a CIP of U.S. patent application Ser. No. 11/876,861 filed Oct. 23, 2007, now U.S. Pat. No. 7,630,806.
This application is related to U.S. patent application Ser. No. 11/735,575 filed Apr. 16, 2007 on the grounds that they contain common subject matter.
These applications are incorporated by reference herein in their entirety.


FIELD OF THE INVENTION
This invention relates generally to systems and methods for improving safe operation of a vehicle by monitoring driving or operation of the vehicle based on detection of objects around a vehicle, and taking action to reduce and ideally eliminate the likelihood of an impact between these objects and the vehicle.
All of the references, patents and patent applications that are referred to herein are incorporated by reference in their entirety as if they had each been set forth herein in full.
Note that this application is one in a series of applications covering safety and other systems for vehicles and other uses. The disclosure herein goes beyond that needed to support the claims of the particular invention set forth herein. This is not to be construed that the inventors are thereby releasing the unclaimed disclosure and subject matter into the public domain. Rather, it is intended that patent applications have been or will be filed to cover all of the subject matter disclosed below and in the current assignee's and current inventors' granted and pending applications. Also please note that the terms frequently used below “the invention” or “this invention” is not meant to be construed that there is only one invention being discussed. Instead, when the terms “the invention” or “this invention” are used, it is referring to the particular invention being discussed in the paragraph where the term is used.
There are numerous methods and components described and disclosed herein. Many combinations of these methods and components are described but in order to conserve space the inventors have not described all combinations and permutations of these methods and components, however, the inventors intend that each and every such combination and permutation is an invention to be considered disclosed by this disclosure. The inventors further intend to file continuation and continuation in part applications to cover many of these combinations and permutations.
BACKGROUND OF THE INVENTION
Background of the invention is set forth in the parent application, U.S. patent application Ser. No. 12/613,071, which is incorporated by reference herein. Definitions of terminology set forth in the '071 application are applicable herein as well.
SUMMARY OF THE INVENTION
A driving monitoring system in accordance with the invention includes a visibility determining system that provides an indication of the visibility of a driver of the vehicle, an image obtaining system oriented to obtain images of an area in front of the vehicle and derive information about an object in the obtained images including distance between the vehicle and the object, and a warning system that warns a driver when a driving maneuver should be aborted based on the visibility of the driver, the distance between the object and the vehicle and movement of the vehicle.
The visibility of the driver means an indication of the distance that the driver can see in front of the vehicle, or in whatever direction the driver is looking. The driver monitoring system herein is not only applicable to a driver looking forward, but may also be applicable to a driver looking, for example, rearward to back up into an adjacent lane and move in a direction opposite to the direction of travel of vehicles in the adjacent lane.
The visibility determining system is preferably configured to consider topography of a road the vehicle is travelling on when providing the indication of the visibility of the driver. For example, it may access a database of topographical information to obtain information about the topography of the road the vehicle is travelling on, this database being arranged partly on the vehicle and/or partly at a site off of the vehicle and provided to the vehicle via a communications link.
Additionally or alternatively, the visibility determining systems is configured to consider atmospheric conditions around the vehicle when providing the indication of the visibility of the driver. To this end, the vehicle may include sensors configured to obtain atmospheric condition information. Additionally or alternatively, a database of atmospheric condition information may be accessed to obtain information about the atmospheric conditions around the vehicle.
If the visibility determining system includes a vehicle illumination system, it may be configured to determine the visibility in consideration of backscatter from the vehicle illumination system.
The image obtaining system may include a lidar or camera system, or any other comparable image obtaining system or even more generally, any system that is capable of obtain data that can be analyzed or processed to obtain information about an object traveling in a direction opposite to the direction of travel of the vehicle.
A processor is advantageously coupled to the visibility determining system, the image obtaining system and the warning system and controls the warning system based on the indication of the visibility of the driver as provided by the visibility determining system and the information about objects travelling in a direction opposite to the direction of travel of the vehicle as derived by the image obtaining system.
A method for monitoring driving of a vehicle in accordance with the invention includes obtaining an indication of visibility of a driver of the vehicle, obtaining images of an area in front of the vehicle, deriving information about an object in the obtained images including distance between the vehicle and the object, and warning a driver via a warning system based at least in part on the determined visibility of the driver, the distance between the vehicle and the object, and movement of the vehicle, when a driving maneuver should be aborted. An indication of the visibility of the driver may be obtained, as noted above, in consideration of topographical information about a road the vehicle is travelling on and/or atmospheric conditions around the vehicle.



BRIEF DESCRIPTION OF THE DRAWINGS
The following drawings are illustrative of embodiments of the invention and are not meant to limit the scope of the invention as encompassed by the claims.
FIG. 1 is a perspective view of an automobile showing a preferred mounting location for the optical blind spot detection system in accordance with the invention.
FIG. 2 is a perspective view of the vehicle of FIG. 1 shown operating on a highway.
FIG. 3A is a detailed view of an automobile mirror assembly showing the location of a LED array or a scanning laser and the CMOS camera.
FIG. 3B is a detailed view of a truck mirror assembly showing the location of a LED array or a scanning laser and the CMOS camera.
FIG. 4 is an overhead view of an alternate blind spot monitoring system where the light source and camera are not collocated.
FIG. 5 is a view similar to FIG. 2 however showing the pattern of laser diode illumination projected from a vehicle mirror preferred installation.
FIG. 6A is a top view of a large truck vehicle showing the coverage of a side blind spot area.
FIG. 6B is a side view of the large truck vehicle of FIG. 6A showing the coverage of a side blind spot area.
FIG. 6C is a side view of the large truck vehicle of FIG. 6A showing the coverage of a side blind spot area using multiple cameras along the side of the vehicle.
FIG. 7A is a top view illustrating the coverage of the forward right hand side of a truck vehicle blind spot.
FIG. 7B is a side view illustrating the coverage of the forward right hand side of a truck vehicle blind spot.
FIG. 8A is a side view illustrating the application to a bus for monitoring the space in front of the bus.
FIG. 8B is a front view illustrating the application to a bus for monitoring the space in front of the bus.
FIG. 9 is a top view of a system applied to monitor the rear of the truck trailer to protect for backup accidents.
FIG. 10 is a block diagram illustrating the blind spot detector, steering control, display and warning system.
FIG. 11 shows an icon display for the instrument panel and an alternate heads up display indicating the position of the host vehicle and the positions of surrounding potentially threatening vehicles as seen from above.
FIG. 12 is an illustration similar to FIG. 11 showing the projection of the images onto a heads-up display.
FIG. 13A illustrates a view of the image as seen by a side rear view camera of FIG. 1.
FIG. 13B illustrates a view of the image of FIG. 13A after a stage of image processing.
FIG. 13C illustrates a view of the image as FIG. 13B after the vehicle has been abstracted.
FIG. 14 illustrates a lane change problem in congested traffic.
FIG. 15 is a perspective view of a vehicle about to impact the side of another vehicle showing the location of the various parts of the anticipatory sensor system of this invention.
FIG. 15A is an enlarged view of a portion of FIG. 15.
FIG. 16 is a flowchart for the lane change problem.
FIG. 17 is an overhead view of a vehicle about to be impacted in the front by an approaching vehicle showing a wave transmitter part of the anticipatory sensor system.
FIG. 18A is a plan front view of the front of a car showing the headlights, radiator grill, bumper, fenders, windshield, roof and hood.
FIG. 18B is a plan front view of the front of a truck showing the headlights, radiator grill, bumper, fenders, windshield, roof and hood.
FIG. 19 is an overhead view of a vehicle about to be impacted in the side by an approaching vehicle showing an infrared radiation emanating from the front of the striking vehicle and an infrared receiver part of the anticipatory sensor system.
FIG. 20 is a side view with portions cutaway and removed of a dual inflator airbag system with two airbags with one airbag lying inside the other.
FIG. 21 is a perspective view of a seatbelt mechanism illustrating a device to release a controlled amount of slack into seatbelt allowing an occupant to be displaced.
FIG. 22 is a front view of an occupant being restrained by a seatbelt having two anchorage points on the driver's right side where the one is released allowing the occupant to be laterally displaced during the crash.
FIG. 22A is an expanded view of the release mechanism within the circle designated 22A in FIG. 22.
FIG. 22B is a view of the apparatus of FIG. 22A within the circle designated 22B and rotated 90 degrees showing the release mechanism.
FIG. 23 is a front view of an occupant being restrained by a seatbelt integral with seat so that when seat moves during a crash with the occupant, the belt also moves allowing the occupant to be laterally displaced during the crash.
FIG. 24A is a front view of an occupant being restrained by a seatbelt and a linear airbag module attached to the seat back to protect entire occupant from his pelvis to his head.
FIG. 24B is a view of the system of FIG. 24A showing the airbag in the inflated condition.
FIG. 25A is a front view of an occupant being restrained by a seatbelt and where the seat is displaced toward vehicle center by the deploying airbag in conjunction with other apparatus.
FIG. 25B is a front view of an occupant being restrained by a seatbelt and where the seat is rotated about a vertical axis in conjunction with other apparatus.
FIG. 25C is a front view of an occupant being restrained by a seatbelt and where the seat is rotated about a longitudinal axis in conjunction with other apparatus.
FIG. 26A is a perspective view with portions cutaway and removed of a vehicle about to impact the side of another vehicle showing an airbag stored within the side door of the target vehicle prior to being released to cushion the impact of the two vehicles.
FIG. 26B is a view of the apparatus of FIG. 26A after the airbag has deployed.
FIG. 27 is a schematic drawing of a variable inflation inflator system in accordance with the invention using two inflators.
FIG. 28 is a schematic drawing of a variable inflation inflator system in accordance with the invention using a single inflator and a variable outflow port or vent.
FIG. 29A shows a situation where a vehicle equipped with an externally deployable airbag for frontal impact protection is about to impact another vehicle.
FIG. 29B shows the condition of the vehicles of FIG. 29A at impact.
FIG. 30A shows a situation where a vehicle equipped with an externally deployable airbag for rear impact protection is about to be impacted by another vehicle.
FIG. 30B shows the condition of the vehicles of FIG. 30A at impact.
FIG. 31A shows a situation where a vehicle equipped with an externally deployable airbag for frontal impact protection is about to impact a pedestrian.
FIG. 31B shows the condition of the vehicle and pedestrian of FIG. 31A at impact.
FIGS. 32A, 32B and 32C show one use of positioning airbags in accordance with the invention wherein a passenger is shown leaning against a door in FIG. 32A, a positioning airbag deploys to move the passenger away from the door as shown in FIG. 32B and a side curtain airbag is deployed when the passenger has been moved away from the door as shown in FIG. 32C.
FIGS. 33A, 33B, 33C and 33D show the manner in which an occupant can be positioned improperly for deployment of a side curtain airbag during a rollover leading to severe injury.
FIGS. 34A, 34B, 34C and 34D show the manner in which an occupant is re-positioned for deployment of a side curtain airbag during a rollover thereby preventing severe injury.
FIG. 35 is a flow chart showing the manner in positioning airbags are used in accordance with the invention.
FIG. 36 is a schematic of the apparatus for deploying multiple airbags in accordance with the invention.
FIG. 37 illustrates an environment of a slow car overtaking problem.
FIG. 38 is a schematic of a system for addressing the overtaking problem in accordance with the invention.



DETAILED DESCRIPTION OF THE INVENTION
1. Exterior Monitoring
1.1 General
Referring now to the drawings wherein the same reference numerals refer to like elements, a perspective semi-transparent view of an automobile is shown generally as 1 in FIG. 1. A driver 2 of the automobile sits on a front seat 4. Five transmitter and/or receiver assemblies 5, 6, 7, 8 and 9 are positioned at various places with views of the environment surrounding the vehicle. A processor such as control circuitry 12 is connected to the transmitter/receiver assemblies 5-9 by appropriate wires, not shown, or wirelessly and controls the transmission of waves or energy from the transmitter portion of the assemblies 5-9 and captures the return signals received by the receiver portion of the assemblies 5-9. Control circuitry 12 usually contains one or more analog to digital converters (ADCs) or frame grabbers, a microprocessor containing sufficient memory and appropriate software including pattern recognition algorithms, and other appropriate drivers, signal conditioners, signal generators, etc. Usually, in any given implementation, only two to four of the transmitter/receiver assemblies would be used.
These optical, for example, transmitter/receiver assemblies 5-9, also referred to herein as transducer assemblies, are comprised of an optical transmitter or light emitting component, which may be an infrared LED, a high power laser diode forming a spotlight, a laser with a diverging lens, a floodlight or a scanning laser assembly, any of which can be pulsed or modulated, and a receiver such as a CCD or CMOS array or pin diode or equivalent photo detector. If modulation is used, it can be frequency, amplitude or pulse-modulated and the modulation scheme can be sine wave or code and if code, the code can be random or pseudorandom. Preferably, a transmitter/receiver assembly comprises an active pixel CMOS array or an HDRC array as discussed below. The transducer assemblies map the location of the objects and features thereof, in a two and/or three-dimensional image as will also be described in more detail below. In a preferred design, range gating is used to locate objects in the field of view and aid in separating an object of interest from other objects and the background. Range gating is also used to aid in low visibility situations such as in fog, smoke, rain and snow.
The foregoing examples of possible wave/energy/light emitting components and light/wave/energy receiver components are not intended to limit the invention and it should be understood by those skilled in the art that other transmitter and receiver components and combinations can be used in accordance with the invention without deviating from the scope and spirit thereof.
In a preferred embodiment, four transducer assemblies 5-8 are positioned around the exterior of the vehicle in the spaces to be monitored, each comprising one or more LEDs or scanning laser diodes and a CMOS array with a light valve and an appropriate lens. Although illustrated together, the illuminating source will frequently not be co-located with the receiving array particularly when triangulation distance measurement is used, as described in more detail below. The LED, laser or other appropriate source of illumination can emit a controlled angle diverging beam of infrared radiation that illuminates a particular space and illuminates an object at a particular point that depends on the location of the object relative to the vehicle and the direction of the LED or laser beam, for example. In some applications, the beam does not diverge and in others, the beam converges.
The image from each array is used to capture two or three dimensions of object position information, thus, the array of assembly 5, which can be located approximately behind the driver's door on the B-pillar provides both vertical and transverse information on the location of an object in the vicinity of the vehicle. A similar view from a location on the passenger side is obtained from the array of assembly 6. The mounting locations of the assemblies 5, 6 shown in FIG. 1 are exemplary and are not intended to limit the possible positions for placement of the assemblies. Other positions for installation of the assemblies on the sides of the vehicle are contemplated. For example, the assemblies 5, 6 could be placed on the side of the vehicle alongside the passenger compartment, engine compartment or trunk compartment.
If the receiving array of assembly 5 contains a matrix of 100 by 100 pixels, then 10,000 pixels or data elements of information will be created each time the system interrogates the space on the driver side of the vehicle, for example. Interrogation of the space on the driver side of the vehicle would entail commanding the assembly 5 to transmit optical waves or energy into the environment surrounding the vehicle by means of the transmitter component of the assembly 5 and receiving any reflected optical waves or energy by the receiver component of the assembly 5.
There are many pixels of each image that can be eliminated because they do not contain any useful information. This typically includes the corner pixels and other areas where an object cannot be located. This pixel pruning can typically reduce the number of pixels by up to 20 percent resulting in approximately 8,000 remaining pixels, for example. The output from each array is then preferably preprocessed to extract the salient features and fed to an artificial neural network, or other pattern recognition system, to identify the object or ascertain the identity of the object. The preprocessing can include edge detection and a variety of filters such as described in U.S. patent application Ser. No. 11/025,501 filed Jan. 3, 2005. Range gating also can be used to eliminate reflections from unwanted objects and to reduce the effects of fog, smoke, rain and snow, for example, as described below.
The preprocessing step frequently makes use of distance or relative motion information to separate one object from another and from other parts of the captured scene. Once this operation is completed for all of the object images, the identification of the objects in the space proximate to the driver side of the vehicle has been determined.
The feature extraction frequently involves identifying the edges of objects in the field of view and the angular orientation of the found edges. The locations of the edges and their orientation can then be input into appropriate recognition software. Other feature extraction techniques are also applicable.
A pattern recognition technique such as a trained neural network can be used to determine which of the trained occupancies most closely corresponds to the measured data. The output of the neural network can be an index of the setup that was used during training that most closely matches the current measured state. This index can be used to locate stored information from the matched trained occupancy. Information that has been stored for the trained occupancy typically includes the locus of the centers of different objects and an appropriate icon. For the case of FIG. 1, it is also known from one of the techniques to be described below where the object is located relative the vehicle.
There are many mathematical techniques that can be applied to simplify the above process. One technique used in military pattern recognition, for example, uses the Fourier transform of particular areas in an image to match by correlation with known Fourier transforms of known images. In this manner, the identification and location can be determined simultaneously. There is even a technique used for target identification whereby the Fourier transforms are compared optically. Other techniques utilize thresholding to limit the pixels that will be analyzed by any of these processes. Still other techniques search for particular features and extract those features and concentrate merely on the location of certain of these features.
A particularly useful technique, as mentioned above, calculates the location of the edges of the object in the blind spot and uses these extracted edges as the features that are fed to the neural network. (See, for example, the Kage et al. artificial retina paper referenced above which, together with the references cited therein, is incorporated herein by reference.)
1.2 Blind Spots
In the discussion below, blind spots are used as an example of monitoring the space around the vehicle. Although the phrase “blind spot” is used, it is the intention of the inventors that this is merely an example of monitoring the exterior of the vehicle and thus “blind spot” will be used as a surrogate for monitoring of any area surrounding the vehicle from the vehicle.
The principle used in this embodiment of the invention is to use images of different views of an object in the blind spot to correlate with known images that were used to train a neural network for blind spot occupancy. Then, carefully measured positions of the known images are used to locate particular parts of the object such as the windshield, tires, radiator grill, headlights, etc.
An alternate approach is to make a three-dimensional map of the object in the blind spot based on the optical energy or waves received by the receiver components of the assemblies 5-9 and to precisely locate these features using neural networks, fuzzy logic or other pattern recognition techniques. One method of obtaining a three-dimensional map is to utilize a scanning laser radar (lidar) system where the laser is operated in a pulse mode and the distance from the object being illuminated is determined using range-gating in a manner similar to that described in various patents on micropower impulse radar to McEwan. (See, for example, U.S. Pat. No. 5,457,394 and U.S. Pat. No. 5,521,600). Range gating is also disclosed in U.S. patent application Ser. No. 11/034,325, now U.S. Pat. No. 7,202,776. Alternately, the laser can be modulated and the phase of the reflected and the transmitted light can be compared to determine the distance to the object.
The scanning portion of the laser radar device can be accomplished using rotating mirrors, mechanical motors, galvanometer mirrors, MEMS mirrors or preferably, a solid state system, for example an acousto-optical utilizing TeO2 as an optical diffraction crystal with lithium niobate crystals driven by ultrasound (although other solid state systems not necessarily using TeO2 and lithium niobate crystals could also be used). An alternate method is to use a micromachined mirror, which is supported at its center or edge and caused to deflect by miniature coils or electrostatically. Such a device has been used to provide two-dimensional scanning to a laser. This has the advantage over the TeO2-lithium niobate technology in that it is inherently smaller and lower cost and provides two-dimensional scanning capability in one small device. The maximum angular deflection that can be achieved with this process is in the order of about 10 degrees. A diverging lens or mirror can be used to achieve a greater angular scan if necessary. An alternate preferred approach is to use passive optical images with superimposed infrared dots created by an array of infrared laser diodes in a manner similar to that described in U.S. Pat. No. 6,038,496.
An alternate method of obtaining three-dimensional information from a scanning laser system is to use multiple arrays to replace the single arrays used in FIG. 1. In the case, the arrays are displaced from each other and, through triangulation, the location of the reflection from the illumination by a laser beam of a point on the object can be determined by triangulation and/or correlation in a manner that is understood by those skilled in the art.
One important point concerns the location and number of optical assemblies. For an automobile, one assembly is generally placed on each side of the vehicle such as shown by assemblies 5, 6. In some embodiments, a third assembly 7 can be placed to view the blind spot behind the vehicle and a fourth assembly 7 can be placed to view in front of the vehicle for automatic cruise control, for example.
1.3 Optical Methods
An alternate configuration is shown at assembly 9 which is a lens arrangement which provides a view of 360 degrees by approximately 20 degrees. Although this camera does not provide as complete a view of objects in the various blind spots, it is possible using a single device to observe areas on both sides as well as the front and back of the vehicle. The same lens is used for receiving the images and for projecting a rotating scanning laser beam that approximately bisects the 20-degree angle. This rotating laser beam is modulated thereby permitting the distance to the reflected laser light to be determined. A rotating mirror, that also serves to deflect the laser beam, captures the returned laser light. This mirror is positioned so that it is above the portion of the lens used for receiving the images such that laser system does not interfere with the imaging system.
Special lenses are used to collect the light from the spherical segmented lens and project the combined image onto a CMOS imager. In some cases, software is provided to remove known distortions for image analysis or, in other cases, this is not necessary as the pattern recognition system has been trained on the combined received image, or a segmented version thereof which divides the image into, for example, four segments representing front, right, rear, and left quadrants.
1.4 Combined Optical and Acoustic Methods
An 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 that can be seen by the system. In spite of these limitations, as shown in Breed et al. (U.S. Pat. No. 5,829,782), ultrasonics can provide sufficient timely information to permit the position and velocity of an approaching object to be accurately known and, when used with an appropriate pattern recognition system, it is capable of positively determining the class of the approaching object. One such pattern recognition system uses neural networks and is similar to that described in the papers by Gorman et al. and in the rear facing child seat recognition system referenced and described in the Breed et al. patent referenced above.
The particular locations of the optical assemblies are selected to provide accurate information as to the locations of objects in the blind spots. This is based on an understanding of what information can be best obtained from a visual image. There is a natural tendency on the part of humans to try to gauge distance from the optical sensors directly. This typically involves focusing systems, stereographic systems, multiple arrays and triangulation, time-of-flight measurement, phase comparison, etc. What is not intuitive to humans is to not try to obtain this distance directly from apparatus or techniques associated with the mounting location but instead to get it from another location. Whereas ultrasound is quite good for measuring distances from the transducer (the z-axis), optical systems are better at measuring distances in the vertical and lateral directions (the x and y-axes).
For monitoring the interior of the vehicle, such as described in U.S. Pat. No. 6,324,453 this can more easily done indirectly by another transducer. That is, the z-axis to one transducer is the x-axis to another. For external monitoring, the preferred approach, as described below, is to use an array of LEDs or a scanning laser and locate the position of the object in blind spot by triangulation, time-of-flight, range-gating or phase measurement although sometimes appropriately located cameras in concert can provide three-dimensional information directly (such as by stereo cameras).
Systems based on ultrasonics and neural networks, and optics and optical correlation have been very successful in analyzing the seated state of both the passenger and driver seats in the interior of automobiles. Such systems are now in production for preventing airbag deployment when a rear facing child seat or an out-of-position occupant is present. The ultrasonic systems, however, suffer from certain natural limitations that prevent the system accuracy from getting better than about 99 percent. These limitations relate to the fact that the wavelength of ultrasound is typically between 3 mm and 8 mm. As a result, unexpected results occur which are due partially to the interference of reflections from different surfaces.
Additionally, commercially available ultrasonic transducers are tuned devices that require several cycles before they transmit significant energy and similarly require several cycles before they effectively receive the reflected signals. This requirement has the effect of smearing the resolution of the ultrasound to the point that, for example, using a conventional 40 kHz transducer, the resolution of the system is approximately three inches, although this has been recently improved. These limitations are also present in the use of ultrasound for exterior vehicle monitoring.
In contrast, the wavelength of the portion of the infrared spectrum that is contemplated for one preferred use in the invention is less than five microns and no significant interferences occur. As a result, resolution of the optical system is determined by the pixel spacing in the CCD or CMOS arrays or the speed of the pin or avalanche diode and scanner when used. For this application, typical arrays have been selected to be approximately 100 pixels by 100 pixels and therefore, the space being imaged can be broken up into pieces that are significantly less than a few inches in size. If greater resolution is required, arrays having larger numbers of pixels are readily available.
Another advantage of optical systems is that special lenses can be used to magnify those areas where the information is most critical and operate at reduced resolution where this is not the case. For example, the area closest to the center of the blind spot can be magnified and those areas that fall out of the blind spot, but are still being monitored, can be reduced. This is not possible with ultrasonic or radar systems where it is even very difficult to get an image of sufficient resolution to permit an identification of the object to be accomplished.
Additional problems of ultrasonic systems arise from the slow speed of sound and diffraction caused by variations in air density. The slow sound speed limits the rate at which data can be collected and thus eliminates the possibility of tracking the motion of an object moving at high speed relative to the vehicle.
1.5 Discussion of the External Monitoring Problem and Solutions
In the embodiment shown in FIG. 1, transmitter/receiver assemblies 5-9 may be designed to emit infrared waves that reflect off of objects in the blind spot, for example, and return thereto. Periodically, the assemblies 5-9, as commanded by control circuit 12, transmits a pulse of infrared waves and the reflected signal is detected by a different assembly. Alternately, a continuous scanning arrangement can be used. The transmitters can either transmit simultaneously or sequentially. An associated electronic circuit and algorithm in control circuit 12 processes the returned signals as discussed above and determines the identity and location of the object in the blind spot. This information is then sent to a warning system that alerts the driver to the presence of the object as described in more detail below. Although a driver side system has been illustrated, a similar system is also present on the passenger side and can be applied to the front and rear of the vehicle.
The accuracy of the optical sensor is dependent upon the accuracy of the camera. The dynamic range of light external to a vehicle exceeds 120 decibels. When a car is driving at night, for example, very little light may be available whereas when driving in a bright sunlight, the light intensity can overwhelm most cameras. Additionally, the camera must be able to adjust rapidly to changes and light caused by, for example, the emergence of the vehicle from a tunnel, or passing by other obstructions such as trees, buildings, other vehicles, etc. which temporarily block the sun and cause a strobing effect at frequencies approaching 1 kHz.
Recently, improvements have been made to CMOS cameras that have significantly increased their dynamic range. New logarithmic high dynamic range technology such as developed by IMS Chips of Stuttgart, Germany, is now available in HDRC (High Dynamic Range CMOS) cameras. This technology provides a 120 dB dynamic intensity response at each pixel in a monochromatic mode. The technology thus has a 1 million to one dynamic range at each pixel. This prevents blooming, saturation and flaring normally associated with CMOS and CCD camera technology. This solves a problem that will be encountered in an automobile when going from a dark tunnel into bright sunlight.
There is also significant infrared radiation from bright sunlight and from incandescent lights. Such situations may even exceed the dynamic range of the HDRC camera and additional filtering including polarizing filters may be required. Changing the bias on the receiver array, the use of a mechanical iris, light valve, or electrochromic glass or liquid crystal or a similar filter can provide this filtering on a global basis but not at a pixel level. Filtering can also be used with CCD arrays, but the amount of filtering required is substantially greater than that required for the HDRC camera.
Liquid crystals operate rapidly and give as much as a dynamic range of 10,000 to 1 but may create a pixel interference effect. Electrochromic glass operates more slowly but more uniformly thereby eliminating the pixel effect. This pixel effect arises whenever there is one pixel device in front of another. This results in various aliasing, Moiré patterns and other ambiguities. One way of avoiding this is to blur the image. Another solution is to use a large number of pixels and combine groups of pixels to form one pixel of information so that the edges and blurred and eliminate some of the problems with aliasing and Moiré patterns. Finally, range gates can be achieved as high speed shutters by a number of devices such as liquid crystals, garnet films, Kerr and Pockel cells or as preferred herein as described in patents and patent applications of 3DV Systems Ltd., Yokneam, Israel including U.S. Pat. No. 6,327,073, U.S. Pat. No. 6,483,094, US2002/0185590, WO98/39790, WO97/01111, WO97/01112 and WO97/01113.
One straightforward approach is the use a mechanical iris. Standard cameras already have response times of several tens of milliseconds range. They will switch, for example, at the frame rate of a typical video camera (1 frame=0.033 seconds). This is sufficiently fast for categorization but probably too slow for dynamic object position tracking when the object in the blind spot is traveling at a high speed relative to the host vehicle.
An important feature of the IMS Chips HDRC camera is that the full dynamic range is available at each pixel. Thus, if there are significant variations in the intensity of light within the vehicle blind spot, and thereby from pixel to pixel, such as would happen when sunlight streams and through a row of trees, for example, the camera can automatically adjust and provide the optimum exposure on a pixel by pixel basis. The use of the camera having this characteristic is beneficial to the invention described herein and contributes significantly to system accuracy. CCDs generally have a rather limited dynamic range due to their inherent linear response and consequently cannot come close to matching the performance of human eyes.
A key advantage of the IMS Chips HDRC camera is its logarithmic response that comes closest to matching that of the human eye. One problem with a logarithmic response is that the variation in intensity from pixel to pixel at an edge may be reduced to the point that the edge is difficult to recognize. A camera with less dynamic range can solve this problem at the expense of saturation of part of the image. One solution is to take several images at a different resolution and combine them in such a manner as to remove the saturation and highlight the edges. This is described in the article “High Dynamic Range Imaging: Spatially Varying Pixel Exposures” referenced above.
Other imaging systems such as CCD arrays can also of course be used with this invention. However, the techniques will be different since the camera is very likely to saturate when bright light is present and to require the full resolution capability when the light is dim. Generally, when practicing this invention, the blind spots will be illuminated with spots or a line of infrared radiation in a scanning mode. If a non-high dynamic range imager is used, the full illumination of the blind spot area may be required.
In a preferred embodiment, infrared illumination is used although this invention is not limited to the use of infrared illumination. However, there are other bright sources of infrared that must be accounted for. These include the sun and any light bulbs that may be present outside the vehicle including headlights from other vehicles. This lack of a high dynamic range inherent with the CCD technology essentially requires the use of an iris, liquid crystal, light valve and/or electrochromic glass or similar filter to be placed between the camera and the scene.
Even with these filters however, some saturation will take place with CCD cameras under bright sun or incandescent lamp exposure. This saturation reduces the accuracy of the image and therefore the accuracy of the system. In particular, the training regimen that must be practiced with CCD cameras is more severe since all of the saturation cases must be considered because the camera is unable to appropriately adjust. Thus, although CCD cameras can be used, HDRC logarithmic cameras such as manufactured by IMS Chips are preferred. HDRC logarithmic cameras not only provide a significantly more accurate image but also significantly reduce the amount of training effort and associated data collection that must be undertaken during the development of the neural network algorithm or other computational intelligence system. Note that in some applications, it is possible to use other more deterministic image processing or pattern recognition systems than neural networks such as optical correlation techniques.
Another important feature of the HDRC camera from IMS Chips is that the shutter time for at least one model is constant at less than about 100 ns irrespective of brightness of the scene. The pixel data arrives at constant rate synchronous with an internal imager clock. Random access to each pixel facilitates high-speed intelligent access to any sub-frame (block) size or sub-sampling ratio and a trade-off of frame speed and frame size therefore results. For example, a scene with 128 K pixels per frame can be taken at 120 frames per second, or about 8 milliseconds per frame, whereas a sub-frame can be taken at as high as 4000 frames per second with 4 K pixels per frame. This combination allows the maximum resolution for the identification and classification part of the object sensing problem while permitting a concentration on those particular pixels which track the leading edge of the object for dynamic position tracking. In fact, the random access features of these cameras can be used to track multiple parts of the image and thus, in some cases, multiple objects simultaneously while ignoring the majority of the image, and do so at very high speed.
For example, several motorcycles or pedestrians in the blind spot can be tracked simultaneously by defining separate sub-frames for each individual object that is not connected to other objects. This random access pixel capability, therefore, is optimally suited for recognizing and tracking multiple objects in a blind spot. It is also suited for monitoring the environment outside of the vehicle other than for the purpose of blind spot detection such as collision avoidance and anticipatory sensing. Photobit Corporation of 135 North Los Robles Ave., Suite 700, Pasadena, Calif. 91101 manufactures another camera with some characteristics similar to the IMS Chips camera. Other competitive cameras can be expected to appear on the market.
Photobit refers to their Active Pixel Technology as APS. According to Photobit, in the APS, both the photo detector and readout amplifier are part of each pixel. This allows the integrated charge to be converted into a voltage in the pixel that can then be read out over X-Y wires instead of using a charge domain shift register as in CCDs. This column and row addressability (similar to common DRAM) allows for window of interest readout (windowing) which can be utilized for on chip electronic pan/tilt and zoom. Windowing provides added flexibility in applications, such as disclosed herein, needing image compression, motion detection or target tracking.
At least one model of the APS utilizes intra-pixel amplification in conjunction with both temporal and fixed pattern noise suppression circuitry (i.e., correlated double sampling), which produces exceptional imagery in terms of wide dynamic range ( ̃75 dB) and low noise ( ̃15 e-rms noise floor) with low fixed pattern noise (<0.15% sat). Unlike CCDs, the APS is not prone to column streaking due to blooming pixels. This is because CCDs rely on charge domain shift registers that can leak charge to adjacent pixels when the CCD register overflows. Thus, bright lights “bloom” and cause unwanted streaks in the image. The active pixel can drive column buses at much greater rates than passive pixel sensors and CCDs.
On-chip analog-to-digital conversion (ADC) facilitates driving high speed signals off chip. In addition, digital output is less sensitive to pickup and crosstalk, facilitating computer and digital controller interfacing while increasing system robustness. A high speed APS recently developed for a custom binary output application produced over 8,000 frames per second, at a resolution of 128×128 pixels. It is possible to extend this design to a 1024×1024 array size and achieve greater than 1000 frames per second for machine vision. All of these features are important to many applications of this invention.
U.S. Pat. No. 5,471,515 provides additional information on the APS camera from Photobit. To put this into perspective, a vehicle passing another vehicle at a relative velocity of 60 mph moves approximately 1 inch per millisecond relative to the slower vehicle. This renders the frame rate and computational times critically important and within the capabilities of the HDRC and APS technologies.
These advanced cameras, as represented by the HDRC and the APS cameras, now make it possible to more accurately monitor the environment in the vicinity of the vehicle. Previously, the large dynamic range of environmental light has either blinded the cameras when exposed to bright light or else made them unable to record images when the light level was low. Even the HDRC camera with its 120 dB dynamic range may be marginally sufficient to handle the fluctuations in environmental light that occur. Thus, the addition of an electrochromic, liquid crystal, light valve or other similar filter may be necessary. This is particularly true for cameras such as the Photobit APS camera with its 75 dB dynamic range.
At about 120 frames per second, these cameras are adequate for cases where the relative velocity between vehicles is low. There are many cases, however, where this is not the case and a higher monitoring rate is required. This occurs for example, in collision avoidance and anticipatory sensor applications as well as in blind spot applications where one vehicle is overtaking another at high speed. The HDRC camera is optimally suited for handling these cases since the number of pixels that are being monitored can be controlled resulting in a frame rate as high as about 4000 frames per second with a smaller number of pixels.
Another key advantage of the HDRC camera is that it is quite sensitive to infrared radiation in the 0.8 to 1 micrometer wavelength range. This range is generally beyond visual range for humans thereby permitting this camera to be used with illumination sources that are not visible to the human eye. This IR sensitivity can be increased through special chip doping procedures during manufacture. A notch frequency filter is frequently used with the camera to eliminate unwanted wavelengths. These cameras are available from the Institute for Microelectronics (IMS Chips), Allamndring 30a, D-70569 Stuttgart, Germany with a variety of resolutions ranging from 512 by 256 to 720 by 576 pixels and can be custom fabricated for the resolution and response time required.
FIG. 2 illustrates the arrangement of FIG. 1 in a traffic situation. Optical assembly 6 on the subject or “host” vehicle contains an illuminating light source and a CMOS array. The illuminating light source of the optical assembly 6, either an array of scanning LEDs or a scanning laser radar device, distributes infrared radiation or energy in the form of distinct narrow angle beams or a line that covers or fills in the blind spot between bounding lines 10 and 11. Any object such as vehicle 23 that is within this blind spot will be illuminated by infrared and the image of object will be captured by the CMOS array of the optical assembly 6.
An optical infrared transmitter and receiver assembly is shown generally at 7 in FIG. 3A and is mounted onto the side rear view mirror 16. Assembly 7, shown enlarged, comprises a source of infrared radiation including an array of 20 infrared LEDs, shown generally at 13, and a CCD or CMOS array 14 of typically 160 pixels by 160 pixels. The CCD or CMOS array 14 is horizontally spaced apart from the LED array 13. In this embodiment, a “heads-up” display can be used to show the driver an artificial image including the host vehicle and objects in the blind spot as described below.
If two spaced-apart CCD arrays are used (e.g., array 14 and array 15 shown in FIG. 3A), then the distance to the various objects within the blind spot can be found by using a triangulation algorithm that locates similar features on both images and determines their relative location on the images. This is frequently referred to as a stereoscopic system such as described in European Patent Application No. EP0885782 A1. An alternate method is to use a lens with a short focal length. In this case, the lens is mechanically focused to determine the clearest image and thereby obtain the distance to the object. This is similar to certain camera auto-focusing systems such as one manufactured by Fuji of Japan. Other methods can be used as described in the patents and patent applications referenced above.
FIG. 3B shows a similar arrangement for mounting on a truck mirror. In this case, since the geometry of the mirror provides greater separation vertically than horizontally, the illumination source 13 is placed on the top of the mirror housing 27 and the imager 14 is placed at the bottom of the mirror housing 27. The “imager” 14 may comprise a CCD array or CMOS array. Two or more spaced-apart imagers 14 can be used in this embodiment as well and the techniques described above applied to determine the relative location of features in images obtained by the imagers 14.
Once a vehicle exterior monitoring system employing a sophisticated pattern recognition system, such as a neural network or optical correlation system, is in place, it is possible to monitor the motions of the object over time, and thereby determine if the object is acting in a predictable manner. If not, the driver of the host vehicle can be warned so that he or she can take evasive action. For example, a vehicle may be in the blind spot and the driver may be losing control of the vehicle as may happen in a passing situation when the passing vehicle has hit a patch of ice. This warning may be sufficient to allow the driver of the host vehicle to slow down and thereby avoid an accident with the out-of-control vehicle.
The system can also be used to turn on the vehicle hazard lights, sound the horn or take other appropriate action in case the driver of the threatening vehicle has fallen asleep and to warn other adjacent vehicles of a potentially dangerous situation. Thus, in general, another vehicular system can be controlled based on the determination of the presence and/or motion of the object detected in the blind spot. The use of a heads-up display is particularly useful for such a warning system since the driver is presumably looking through the windshield. Out-of-control monitoring can also apply to the host vehicle if its trajectory is unexpected relative to objects along the roadside or other proximate vehicles.
Infrared waves are shown coming from side transducer assemblies 17 and 18 in FIG. 4. As such, assemblies 17, 18 constitute infrared transmitters. In this case, CMOS imagers 19 and 20 are mounted on the side rear view mirrors providing ample displacement for triangulation calculations. Thus, FIG. 4 shows one arrangement of non-collocated transmitters and receivers, it being understood that other arrangements in which the transmitters are not collocated with the receivers are also within the scope and spirit of the invention.
FIG. 5 illustrates two optical systems each having a source of infrared radiation and a CCD or CMOS array receiver. In this embodiment, transducer assemblies 5 and 6 are CMOS arrays having 160 by 160 pixels covered by a lens. The lens is carefully designed so that it completely covers the blind spot area under surveillance. One such sensor placed by the left outside mirror where it can monitor the entire vehicle left exterior blind spot with sufficient resolution to determine the occupancy of the blind spot. CCD's such as those used herein are available from Marshall Electronics Inc. of Culver City, Calif.
The lens need not be non-distorting. The distortion of a lens can be designed by modifying the shape of the lens to permit particular portions of the exterior of the passenger compartment to be observed. The particular lens design will depend on the location on the vehicle and the purpose of the particular receiver. In this example, the light source, which is an array of modulated LEDS is collocated with the CMOS imager. Note that although only four beams are illustrated on each side of the vehicle, typically twenty such beams are used. A modulated scanning laser can alternately be used.
CCD arrays are in common use in television cameras, for example, to convert an image into an electrical signal. For the purposes herein, a CCD will be used interchangeably with CMOS and will be defined to include all devices, including CMOS arrays, TFA arrays, focal plane arrays, artificial retinas and particularly HDRC and APS arrays, which are capable of converting light frequencies, including infrared, visible and ultraviolet, into electrical signals. The particular CCD array used for many of the applications disclosed herein is implemented on a single chip that is less than two centimeters on a side. Data from the CCD array is digitized and sent serially to an electronic circuit (at times designated 12 herein) containing a microprocessor for analysis of the digitized data. In order to minimize the amount of data that needs to be stored, initial processing of the image data can take place as it is being received from the CCD array. In some cases, some image processing can take place on the chip such as described in the Kage et al. artificial retina article referenced above.
One method of determining distance to an object directly without resorting to range finders, requiring multiple arrays, is to use a mechanical focusing system. However, the use of such an apparatus is cumbersome, expensive, and slow and has questionable reliability. An alternative is to use the focusing systems described in U.S. Pat. No. 5,193,124 and U.S. Pat. No. 5,003,166. However, such systems can require expensive hardware and/or elaborate algorithms and again are slow.
Another alternative is where an infrared source having a wide transmission angle such that the entire contents of the blind spot illuminated, a sort of infrared floodlight. The receiving CCD transducers can be spaced apart so that a stereographic analysis can be made by the control circuitry 12. This circuitry 12 contains a microprocessor with appropriate pattern recognition algorithms along with other circuitry as described above. In this case, the desired feature to be located is first selected from one of the two returned images from either of the CCD transducers. The software then determines the location of the same feature, through correlation analysis or other methods, on the other image and thereby, through analysis familiar to those skilled in the art, determines the distance of the feature from the transducers.
Transducer assemblies 5 and 6 are illustrated mounted onto the side mirrors of the vehicle, however, since these transducers are quite small, typically approximately 2 cm on a side, they could alternately be mounted onto the side of the vehicle or many other locations which provide a clear view of the blind spot.
A new class of laser range finders has particular application here. This product, as manufactured by Power Spectra, Inc. of Sunnyvale, Calif., is a GaAs pulsed laser device which can measure up to 30 meters with an accuracy of <2 cm and a resolution of <1 cm. This system can be implemented in combination with transducer assemblies 5 or 6. Once a particular feature of an object in the blind spot has been located, this device can be used in conjunction with an appropriate aiming mechanism to direct the laser beam to that particular feature. The distance to that feature is then known to within about 2 cm and with calibration even more accurately.
In addition to measurements within the blind spot, this device has particular applicability in anticipatory sensing applications exterior to the vehicle. An alternate technology using range gating or phase measurements to measure the time-of-flight of electromagnetic pulses with even better resolution can be implemented based on the teaching of the McEwan patents or the Intelligent Technologies Intl patent application listed above or by modulation of the laser beam and using phase measurements such as disclosed in U.S. Pat. No. 5,653,462.
FIG. 6A is an overhead view and FIG. 6B a side view of a truck showing some preferred mounting locations of optical exterior vehicle monitoring sensors (transmitter/receiver assemblies or transducers) 160, 161. In a typical device, the diameter of the lens is approximately 2 cm and it protrudes from the mounting surface by approximately 1 cm. This small size renders these devices almost unnoticeable by observers exterior to the vehicle.
Since the sensors and transducer assemblies used in some embodiments of the invention are optical, it is important that the lens surface remains relatively clean. Control circuitry 120 contains a self-diagnostic feature where the image returned by a transducer assembly or sensor is compared with a stored image and the existence of certain key features is verified. If a receiver part of an assembly or sensor fails this test, a warning is displayed to the driver that indicates that cleaning of the lens surface is required.
The truck system shown in FIGS. 6A and 6B illustrates the use of a single blind spot detection system for the entire length of truck. The fundamental issue that determines the size of the blind spot that can be monitored with a single system relates to the ability to measure the location of the object. When a HDRC camera is used, if an object can seen in the blind spot by the human eye, then the camera should also be able to obtain a reasonable image. At night, this would require that the object in blind spot have some form of attached illumination. On a dark cloudy night, the human eye has trouble seeing a car parked along the roadway with its lights extinguished. The more distant the object, the more difficult it is to obtain a recognizable image if illumination is not present.
A significant improvement to the situation occurs if the blind spot is flooded even with low-level infrared radiation. This argues for an infrared floodlight in addition to the distance measuring infrared system. If an infrared floodlight is used along with multiple cameras displaced from one another, then the location of object in the blind spot can be determined by optical correlation between the two images and by triangulation calculations. This may be a practical solution for trucks especially those containing multiple trailers. A truck with multiple cameras placed along the left side of the vehicle is illustrated in FIG. 6C. Of course, a bright IR floodlight based on a high powered diode laser and appropriate optics can be used.
The other limiting case is when bright sunlight is present and only a single imager is used for a particular blind spot. For this case, a scanning laser infrared beam, or a high powered laser diode spotlight, can still be distinguished as a reflection off of an object in the blind spot providing a narrow notch filter is used to eliminate all frequencies other than the particular infrared frequency used. Even in this case, the distance where the reflected infrared beam can be ascertained in bright sunlight can be limited to perhaps fifteen meters. Therefore, this system can be marginal for long trucks unless multiple systems are used along the side of the truck as shown at 28 in FIG. 6C. Note that certain mid-infrared frequencies having wavelengths above 10 microns are particularly good in that the radiation from the sun is significantly attenuated. Low cost imagers are not currently available but are under development for these frequencies.
From the above discussion, it would appear that multiple cameras may be the only viable solution for long trucks. A further problem arises in this system design in that if the cameras are located on different trailers, or for some other reason can move relative to each other, then the analysis computer must know the location and orientation of each camera. There are a variety of ways of accomplishing this orientation such as through locating laser beams or monitoring the relative positions of the various components of the truck. In one example, a laser beam is used to illuminate a spot on the road that can be observed from multiple camera locations. Using the position of this reflected dot in the images acquired by various cameras, the relative orientation is approximately determined. Naturally, more complicated and sophisticated systems are possible. RFID tags offer another method of determining the relative location of a point on a trailer relative to the tractor if multiple antennas are used and if the relative time of arrival of the received RFID signals are measured.
The blind spot monitoring systems described above in FIGS. 6A, 6B and 6C are mainly applicable for blind spots occurring during highway travel. For urban travel of a truck where frequent turns are made, another blind spot occurs on right hand side of the vehicle (in countries where vehicles drive on the right side of the road) and extends somewhat forward of the vehicle and back somewhat beyond vehicle cab. This area, which cannot be seen by the driver, can contain pedestrians, small vehicles, bicycles, curbs, fire hydrants, motorcycles, as well as a variety of other objects. Another more local blind spot system that covers this area is therefore necessary, as illustrated in FIGS. 7A and 7B and which is designated 24.
The applications described herein have been illustrated mainly using the driver side of the vehicle. The same systems of determining the position of an object in the blind spot are also applicable on the passenger side.
A significant number of children are killed every year by being run over by school buses. This tragic accident occurs when a child leaves the school bus and walks in front of the bus in the driver's blind spot. The driver starts driving the bus and strikes the child. A blind spot monitor of this invention, i.e., one or more transducer assemblies, is shown mounted on the front of school bus 25 near the top of the engine compartment 180 in FIGS. 8A and 8B. This monitoring system alerts the driver of the presence of an object obstructing the path of the school bus 25.
The system shown in FIG. 9 illustrates a blind spot monitoring system 26 built according to the teachings of this invention. The system can utilize a high dynamic range camera, identification and ranging capability with or without illumination or, alternately, a linear scanning laser range meter or laser spotlight. The view provided to the driver shows the location, size and identity of all objects that are within the path of the backing vehicle. The display provides maximum contrast by using icons to represent the host vehicle and the objects in the blind spot. Although this is shown for a truck, it is equally applicable for other vehicles including buses and automobiles. It can also be used in a rear impact anticipatory sensor where both the displacement and velocity, by either Doppler or differencing distance measurements, of the approaching object can be determined.
The monitoring system 26 could be activated whenever the vehicle is in reverse, unless it is also used for rear impact anticipatory sensing. Thus, the system 26 would not be needed when the vehicle is traveling forward. When the gear is shifted into reverse, a sensor could be provided to detect the change in gear and then activate the monitoring system 26. Similarly, a monitoring system which is for forward blind spot such as in front of the bus 25 shown in FIGS. 8A and 8B could be designed to activated only when the vehicle is in forward gear and not stopped or in reverse. As such, when the gear is shifted into forward, the system 25 would be activated.
If both a forward and rear monitoring system are provided, then the activation of both of these monitoring systems would not need to be simultaneous but could depend on the direction of travel of the vehicle. In this case, a single display could be provided to the driver and alternatively display the contents of the forward blind spot or rear blind spot depending on the direction of the travel of the vehicle, i.e., in which gear the vehicle is in.
FIG. 10 illustrates a block diagram showing interface between five blind spot monitoring systems and control circuitry 12. The control circuitry 12 monitors the output from the five blind spot monitoring systems and creates icons and places the icons on a display 30, 31 that shows the host vehicle and all objects in the immediate vicinity of the host vehicle. Software is provided in the microprocessor to sound a warning signal or activate haptic actuators 33 under a predetermined set of circumstances such as an attempt by the driver to change lanes into a lane occupied by an object in the blind spot. This warning signal may also be activated if the driver activates the turn signal. In addition to the audio warning signal, a visual flashing signal provided on the display and a vibration or pressure or torque or other haptic signal applied to the steering wheel to prevent or make it more difficult for driver execute the maneuver.
The display 30, 31 would selectively or alternatively display the contents of each blind spot. A screen-within-a-screen type display could also be used to display one blind spot in a majority of the screen and another blind spot in a small portion of the screen. As noted above, the blind spot displayed could depend on the status of the gear of the vehicle. The blind spot displayed could also depend on the direction of turning of the front wheels, the direction of turning of the rear wheels and/or the activation of the right or left turn signals.
2. Displays
FIG. 11 illustrate a control module 36 that contains a variety of electronic components 37-42. The control module is connected to the blind spot monitoring system including the transducer assemblies 5-9 by wires, not shown, or wirelessly and in turn it connects to a display on the instrument panel 31 or a heads-up display 30. Based on the calculations performed in a microprocessor 41, the control module 36 creates the icons on displays 30 and 31 and additionally initiates audio and haptic warnings as described above. The connection between the control module 36 and the audio and haptic actuators may be a wired connection or a wireless connection.
FIG. 12 is a further illustration of the heads-up display 30 shown in FIG. 11. The heads-up display 30 is constructed according to well-known principles and the image is projected focused in front of vehicle 29 such that the driver can observe the image without taking his or her eyes from the road.
3. Identification
The use of trainable pattern recognition technologies such as neural networks is an important part of this invention, although other non-trained pattern recognition systems such as fuzzy logic, correlation, Kalman filters, and sensor fusion can also be used. These technologies are implemented using computer programs to analyze the patterns of examples to determine the differences between different categories of objects. These computer programs are derived using a set of representative data collected during the training phase, called the training set. After training, the computer programs output computer algorithms containing the rules permitting classification of the objects of interest based on the data obtained after installation on the vehicle.
These rules, in the form of an algorithm, are implemented in the system that is mounted onto the vehicle. The determination of these rules is important to the pattern recognition techniques used in this invention. Neural networks either singularly or combination neural networks are contemplated by this invention. Combination neural networks are groups of two or more neural networks and include modular neural networks and ensemble neural networks among others. Also cellular neural networks and support vector machines are also contemplated by this invention.
Artificial neural networks using back propagation are thus far one of the most successful of the rule determination approaches. However, research is underway to develop systems with many of the advantages of back propagation neural networks, such as learning by training, without the disadvantages, such as the inability to understand the network and the possibility of not converging to the best solution. In particular, back propagation neural networks will frequently give an unreasonable response when presented with data than is not within the training data. It is known that neural networks are good at interpolation but poor at extrapolation. A combined neural network fuzzy logic system, on the other hand, can substantially solve this problem. Additionally, there are many other neural network systems in addition to back propagation. In fact, one type of neural network may be optimum for identifying the contents of the blind spot and another for determining the location of the object dynamically.
The discussion thus far has identified pattern recognition systems and particularly neural network pattern recognition systems to be used to identify the contents of the blind spot. One particular neural network architecture has been particularly successful in this field. This is known as modular neural networks. The concept behind modular neural networks is that when a complicated task is to be accomplished by a neural network, significant improvements in speed and accuracy can sometimes be obtained if the overall problem is divided into a number of smaller problems. A separate neural network is then assigned each sub-task. Thus, a network of neural networks is created.
When a human observes a tree, the human mind concentrates on characteristics of that tree and not on characteristics of an automobile. Thus, the human mind appears to operate also as a modular neural network. There are many ways of applying this concept to blind spot monitoring. Since both the identity and the location of object in the blind spot are to be determined, it is logical to therefore separate the problem into a first neural network that determines the identity of the object and then a variety of additional neural networks that, given the identity of the object, determine its location. In addition, a separate neural network may be trained to segregate any unknown objects from data that are not understood by the neural networks because nothing similar was a part of the training database.
Additional tasks that can be allocated to specific neural networks are to determine environment that the vehicle is operating in. Obviously, an automobile in a blind spot looks considerably different at night with its headlights on than in bright sunlight. The identification and also the position determining tasks can be more accurate if they are segregated by lighting conditions. Similarly, the presence of fog, smoke, rain, snow, soiled lenses, and other factors can have a significant effect on the system accuracy and allocated to separate groups of neural networks.
In some embodiments of this invention, the rules are sufficiently obvious that a trained researcher can look at the returned optical signals and devise an algorithm to make the required determinations. In others, artificial neural networks are frequently 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. and another from International Scientific Research in Panama City, Panama. Numerous books and articles, including more than 500 U.S. patents, describe neural networks in great detail and thus the theory and application of this technology is well known and will not be repeated here. Neural networks are now beginning to gain more widespread use in the automotive industry including their use for engine control, occupant spatial sensing for the control of airbags, side and frontal crash sensor algorithms and vehicle diagnostic systems.
The system generally used in this invention for the determination of the presence of an object in the blind spot is the artificial neural network or a neural-fuzzy system. In this case, the network operates on the returned signals from the CCD or CMOS array as sensed by transducer assemblies such as 5, 6, 7, 8 and 9 in FIG. 1, for example. For the case of the left blind spot, through a training session, the system is taught to differentiate between many cases including automobiles, pedestrians, bicycles, trucks, animals, motorcycles, fences, guard rails, parked vehicles etc. This is done by conducting a large number of experiments where data from each of these objects is captured in a variety of positions, velocities and vehicle operating conditions (rain, night, bright sunlight, rural roads, interstate highways, etc.). As many as 1,000,000 such experiments are run before the neural network is sufficiently trained and validated so that it can differentiate among the various cases and output the correct decision with a very high accuracy.
Once the network is determined, it is possible to examine the result to determine, from the algorithm created by the neural network algorithm generating software, the rules that were finally arrived at by the trial and error training technique. In that case, the rules can then be programmed into a microprocessor. Alternately, a neural computer can be used to implement the network directly. In either case, the implementation can be carried out by those skilled in the art of pattern recognition using neural networks.
Many systems are now on the market that monitor obstructions in the rear of a vehicle and warn the driver of the existence of such obstructions when the driver is backing a vehicle. The technologies currently used include radar, ultrasound and TV cameras. Neither radar nor ultrasound are generally capable of identifying the object and most such systems cannot locate the object which might allow the driver to slightly change his or her direction and avoid a curb or pole, for example. The television camera systems typically do not have illumination sources and at best produce a poor television image to the driver that is difficult to see in sunlight.
FIGS. 13A, 13B and 13C illustrate one preferred method of separating an object in the blind spot from other objects in preparation for input into a neural network for identification and/or position determination. FIG. 13A illustrates a view of the image as seen by a side rear view transducer assembly 7 of FIG. 1.
Various filters are employed to simplify and idealize the view the output of which is shown in FIG. 13B. A variety of technologies exist to eliminate remaining background objects and isolate the vehicle to arrive at the image as shown in FIG. 13C.
In one preferred method, the distance to the objects to the left and right of the vehicle can determined by the laser radar system described above. This permits the elimination of objects that are not in the same plane as the blind spot vehicle. Any of the distance measuring schemes described above along with pattern matching or pattern linking techniques can be used to extract the vehicle. Other techniques involve the use of relative motion of the object in the blind spot that may involve the use of optical flow calculations. A preferred method is through the use of range gating as discussed above. No one system is ideal unless the full three-dimensional representation of entire scene has been achieved. Therefore, a variety of techniques are used depending on particular problem at hand.
FIG. 14 illustrates a lane-changing problem in congested traffic. In this illustration, the driver of vehicle 46 wants to change lanes to pass vehicle 47. However, vehicle 45 is in the blind spot and if vehicle 46 attempts this lane change, an accident may result. Using the teachings herein, the driver of vehicle 46 will be made aware either through a visual display or through warning signals, optical, audio and/or haptic, should the driver attempt to execute such a lane change. The driver may be made aware of the presence of the vehicle 45 in the blind spot upon activation of the turn signal, upon detection of the beginning of the lane change as reflected in the turning of the steering wheel or front wheels of the vehicle and/or by the presence of an icon showing the vehicle 45 in the display 30, 31.
A detailed discussion of pattern recognition technology as applied to the monitoring and identification of occupants and objects within a vehicle is discussed in Breed et al. (U.S. Pat. No. 5,829,782). Although the application herein is for the identification of objects exterior to the vehicle, many of the same technologies, principles and techniques are applicable.
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.
4. Anticipatory Sensors
FIG. 15 is an angular perspective overhead view of a vehicle 50 about to be impacted in the side by an approaching vehicle 51, where vehicle 50 is equipped with a blind spot monitor or anticipatory sensor system showing a transmitter 52 transmitting electromagnetic, such as infrared, waves toward vehicle 51. This is one example of many of the uses of this invention for exterior monitoring.
The transmitter 52 is connected to an electronic module 56. Module 56 contains circuitry 57 to drive transmitter 52 and circuitry 58 to process the returned signals from receivers 53 and 54. Circuitry 58 contains a neural computer 59, which performs the pattern recognition determination based on signals from receivers 53 and 54 (FIG. 15A). Receivers 53 and 54 are mounted onto the B-Pillar of the vehicle and are covered with a protective transparent cover. An alternate mounting location is shown as 55 which is in the door window trim panel where the rear view mirror (not shown) is frequently attached.
One additional advantage of this system is the ability of infrared to penetrate fog and snow better than visible light, which makes this technology particularly applicable for blind spot detection and anticipatory sensing applications. Although it is well known that infrared can be significantly attenuated by both fog and snow, it is less so than visual light depending on the frequency selected. (See for example L. A. Klein, Millimeter-Wave and Infrared Multisensor Design and Signal Processing, Artech House, Inc, Boston 1997, ISBN 0-89006-764-3). Additionally, much of the reflection from fog, smoke, rain or snow can be filtered out using range gating, which masks reflections that come from certain distance ranges from the sensor.
Radar systems, which may not be acceptable for use in the interior of the vehicle, are now commonly used in sensing applications exterior to the vehicle, police radar being one well-known example. Miniature radar systems are now available which are inexpensive and fit within the available space. Such systems are disclosed in the McEwan patents described above. One particularly advantageous mode of practicing the invention for these cases, therefore, is to use a CW radar or pulsed laser radar system, along with a CCD array. In this case, the radar is used to determine distance and the CCD for identification.
In a preferred implementation, transmitter 52 is an infrared transmitter and receivers 53, 54 and 55 are CCD transducers that receive the reflected infrared waves from vehicle 51. In the embodiment shown in FIG. 15, an exterior-deployed airbag 60 is shown which deploys in the event that a side impact is about to occur as described in U.S. Pat. No. 6,343,810 and elsewhere herein.
In most of the applications above, the assumption has been made that either a scanning spot, beam or a line of light will be provided. This need not be the case. The light that is emitted to illuminate the object can be structured light. Structured light can take many forms starting with, for example, a rectangular or other macroscopic pattern of light and dark can be superimposed on the light by passing it through a filter. If a similar pattern is interposed between the reflections and the camera, a sort of pseudo-interference pattern can result sometimes known as Moiré patterns. A similar effect can be achieved by polarizing transmitted light so that different parts of the object that is being illuminated are illuminated with light of different polarization. Once again, by viewing the reflections through a similarly polarized array, information can be obtained as to where the source of light came from which is illuminating a particular object. Different modulation schemes can also be used to create different patterns and the modulation can be varied in time for particular applications.
As disclosed in U.S. Pat. No. 5,653,462 for interior vehicle monitoring and U.S. Pat. No. 6,343,810 for exterior monitoring, a modulated light source can be used to determine the distance to an object either interior or exterior of the vehicle. The basic principle is that the phase of the reflected light is compared to the phase of the transmitted light and the distance to the reflecting object is determined by the phase difference. There are many ways of implementing this principle. One that has recently been disclosed called the photonic mixing device or PMD. In this device, an optical filter is modulated with the same frequency and the phase that is used to modulate the transmitted light beam. In the PMD, this principle is executed on a pixel by pixel basis and incorporated into the CMOS array structure. Although still falling within the teachings of this invention, this results in an unnecessarily complicated structure. An alternate method will now be described.
An object in the blind spot or inside a vehicle is illuminated by modulated light and reflects this light back to a receiver wherein the phase relationship between the reflected light and the transmitted light is a function of the distance to the reflecting surface. For every pixel, the comparison will be made to the same frequency and phase since only one source of illuminating modulated light has been used to illuminate the entire object. Therefore, there is no advantage in attempting to influence each pixel separately with the modulation frequency and phase. A similar and preferable approach is to use a single light valve, electronic shutter or range gate to modulate all of the light coming back from the illuminated object.
The technology for modulating a light valve or electronic shutter has been known for many years and is sometimes referred to as a Kerr cell or a Pockel cell. More recent implementations are provided by the technology of 3DV discussed above. These devices are capable of being modulated at up to 10 billion cycles per second. For determining the distance to a vehicle in the blind spot, modulations between 5 and 100 MHz are needed. The higher the modulation frequency, the more accurate the distance to the object can be determined. However, if more than one wavelength, or better one-quarter wavelength, exists between the host vehicle and the object, then ambiguities result. On the other hand, once a longer wavelength has ascertained the approximate location of the vehicle, then more accurate determinations can be made by increasing the modulation frequency since the ambiguity will now have been removed.
In one preferred embodiment of this invention, therefore, an infrared floodlight, which can be from a high power laser diode, is modulated at a frequency between 5 and 100 MHz and the returning light passes through a light valve such that amount of light that impinges on the CMOS array pixels is determined by a phase difference between the light valve and the reflected light. By modulating a light valve for one frame and leaving the light valve transparent for a subsequent frame, the range to every point in the camera field of view can be determined based on the relative brightness of the corresponding pixels. Pulse or noise or pseudo noise modulation can also be used which has the advantage that the return signal can be more easily differentiated from transmissions from other vehicles. Other differentiation schemes are based on synchronizing the transmissions to the vehicle GPS location, direction of travel or some other such scheme.
Once the range to all of the pixels in the camera view has been determined, range gating becomes a simple mathematical exercise and permits objects in the image to be easily separated for feature extraction processing. In this manner, many objects in the blind spot can be separated and identified independently.
As mentioned above, it is frequently not possible to separate light from a broad illumination source from sunlight, for example. It has been determined, however, that even in the presence of bright sunlight a reflection from a narrow beam of infrared laser light, or a broader beam from a high power laser diode, can be observed providing a narrow notch frequency filter is used on the light entering the receiver. The principles described above, however, are still applicable since a sampling of pixels that have been significantly illuminated by the narrow laser beam can be observed and used for ranging.
The technique of using a wide-angle infrared floodlight is particularly useful at night when objects, especially those without self-contained lights, are difficult to observe. During bright sunlight, there is considerable information from the visual view taken by the cameras to perform feature extraction, identification, ranging etc. utilizing other techniques such as relative motion. Thus, a superior blind spot monitoring system will make use of different techniques depending on the environmental conditions.
In more sophisticated implementations of the present invention, there can be an interaction between the imaging system and the aiming direction of the infrared laser beam. For example, a particular limited area of the image can be scanned by the infrared system when the imaging system is having difficulty separating one object from another. It is expected, as the various technologies described above evolve, that very smart blind spot, anticipatory sensors and general exterior monitoring systems based on the teachings of this invention will also evolve.
In one implementation, the goal is to determine the direction that a particular ray of light had when it was transmitted from the source. Then, by knowing which pixels were illuminated by the reflected light ray along with the geometry of the transducer mountings, the distance to the point of reflection off of the object can be determined. This requires that the light source not be collocated with the CCD array. If a particular light ray, for example, illuminates an object surface that is near to the source, then the reflection off of that surface will illuminate a pixel at a particular point on the CCD or CMOS array. If the reflection of the same ray however occurs from a more distant surface, then a different pixel will be illuminated in the CCD array. In this manner, the distance from the surface of the object to the CCD can be determined by triangulation formulas.
Similarly, if a given pixel is illuminated in the CCD from a reflection of a particular ray of light from the transmitter, and the direction in which that ray of light was sent from the transmitter is known, then the distance to the object at the point of reflection can be determined. If each ray of light is individually recognizable and therefore can be correlated to the angle at which it was transmitted, then a full three-dimensional image can be obtained of the object that simplifies the identification problem.
The coding of the light rays coming from the transmitter can be accomplished in many ways. One method is to polarize the light by passing the light through a filter whereby the polarization is a combination of the amount and angle of the polarization. This gives two dimensions that can therefore be used to fix the angle that the light was sent. Another method is to superimpose an analog or digital signal onto the light that could be done, for example, by using an addressable light valve, such as a liquid crystal filter, electrochromic filter, or, preferably, a garnet crystal array. Each pixel in this array would be coded such that it could be identified at the CCD. Alternately, the transmitted radiation can be AM or FM modulated to also provide source identification.
The technique described above is dependent upon either changing the polarization or using the time or frequency domain, or a combination thereof, to identify particular transmission angles with particular reflections. Spatial patterns can also be imposed on the transmitted light that generally goes under the heading of structured light, as discussed above. The concept is that if a pattern is identifiable, then either the distance can be determined by the displacement of the pattern in the field of view if the light source is laterally displaced from the receiver or, if the transmission source is located on the same axis but axially displaced with the receiver, then the pattern expands at a different rate as it travels toward the object and then, by determining the size of the received pattern, the distance to the object can be determined. In some cases, Moiré pattern techniques are utilized.
A further consideration to this invention is to use the motion of the object, as determined from successive differential arrays, for example, to help identify that there is in fact an object in the blind spot. Differential motion can be used to separate various objects in the field of view and absolute motion can be used to eliminate the background, if desired.
In a preferred implementation, transmitter 52 is an ultrasonic transmitter operating at a frequency of approximately 40 kHz, although other frequencies could be used. Similarly, receivers 53 and 54 are ultrasonic receivers or transducers and receive the reflected ultrasonic waves from vehicle 51.
A “trained” pattern recognition system as used herein will mean a pattern recognition system that is trained on data representing different operating possibilities. For example, the training data may constitute a number of sets of a signal from receiver 53 represented the returned waves received thereby, a signal from receiver 54 representing the returned waves received thereby and one or more properties of the approaching object, e.g., its form or shape, size or weight, identity, velocity, breadth and relative distance. Once trained, the trained pattern recognition system will be provided with the signals from receivers 53, 54 and categorize the signals that would lead to a determination by the system of the property or properties of the approaching object, e.g., its size or identity.
Some examples of anticipatory sensing technologies follow:
In a passive infrared system, a detector receives infrared radiation from an object in its field of view, in this case the approaching object is most likely another vehicle, and processes the received infrared radiation radiating from the vehicle's engine compartment. The anticipatory sensor system then processes the received radiation pattern to determine the class of vehicle, and, along with velocity information from another source, makes an assessment of the probable severity of the pending accident and determines if deployment of an airbag is required. This technology can provide input data to a pattern recognition system but it has limitations related to temperature. The sensing of a non-vehicle object such as a tree, for example, poses a particular problem. The technology may also fail to detect a vehicle that has just been started especially if the ambient temperature is high. Nevertheless, for use in the identification of approaching vehicles the technology can provide important information especially if it is used to confirm the results from another sensor system.
In a passive audio system one or more directional microphones can be aimed from the rear of the vehicle can determine from tire-produced audio signals, for example, that a vehicle is approaching and might impact the target vehicle which contains the system. The target vehicle's tires as well as those to the side of the target vehicle will also produce sounds which need to be cancelled out of the sound from the directional microphones using well-known noise cancellation techniques. By monitoring the intensity of the sound in comparison with the intensity of the sound from the target vehicle's own tires, a determination of the approximate distance between the two vehicles can be made. Finally, a measurement of the rate of change in sound intensity can be used to estimate the time to collision. This information can then be used to pre-position the headrest, for example, or other restraint device to prepare the occupants of the target vehicle for the rear end impact and thus reduce the injuries therefrom. A similar system can be used to forecast impacts from other directions. In some cases, the microphones will need to be protected in a manner so as to reduce noise from the wind such as with a foam protection layer. This system provides a very inexpensive anticipatory crash system.
In a laser optical system, the transmitter 52 comprises an infrared laser beam which is used to momentarily illuminate an object as illustrated in FIG. 15 where transmitter 52 is such a laser beam transmitter. In some cases, a charge coupled device (a type of TV camera), or a CMOS optical sensor array, is used to receive the reflected light and would be used as one or both of the receivers 53 and 54. The laser can either be used in a scanning mode, or, through the use of a lens, a cone of light or a large diameter beam can be created which covers a large portion of the object. When the light covers a significant area a high powered laser diode can be used. When such a high powered laser diode is used the distance to the closest reflecting object can be measured and the intensity of the radiation at that distance controlled so as to maintain eye safety conditions. If the atmospheric conditions are also known so that the dissipation of the transmitted light can be determined then added power can be used to compensate for the losses in the atmosphere still maintaining eye safety conditions. Additionally, the beam can be made to converge at just the rate to keep the illumination intensity constant at different distances from the source. To implement some of these concepts, appropriate lens systems may be required. In some cases the lenses must respond more rapidly then possible with conventional lenses. Solid state acousto-optical based or liquid based lenses or MEMS mirrors offer the potential to operate at the required speed.
In each case, a pattern recognition system, as defined above, is used to identify and classify the illuminated object and its constituent parts. The scanning implementation of the laser system has an advantage that the displacement of the object can be calculated by triangulation of the direction of the return light from the transmitted light providing the sensor and transmitter as displaced from one another. This system provides significant 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 and the attenuation that results in bad weather conditions such as heavy rain, fog or snow storms. As the cost of lasers comes down in the future, this system will become more competitive. The attenuation problem is not as severe as might be expected since the primary distance of concern for anticipatory sensors as described here is usually less than three meters and it is unlikely that a vehicle will be operated with a visibility of only a few meters. If the laser operates in the infrared region of the spectrum, the attenuation from fog is less than if it is operated in the visible part of the spectrum. As mentioned above, any remaining atmosphere scattering or absorption problems can be alleviated with range gating.
Radar systems have similar properties to the laser system discussed above with the advantage that there is less attenuation in bad weather. 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. This can have an effect in the ability of the system to identify different objects and particularly to differentiate between different truck and automobile models. It is also more difficult to use radar in a triangulation system to obtain a surface map of the illuminated object as can be done with an infrared laser. However, for anticipatory sensing the object of interest is close to the host vehicle and therefore there is substantial information from which to create an image for analysis by a pattern recognition system providing a narrow beam radar is used. Radar remains a high price option at this time but prices are dropping.
The portion of the electromagnetic spectrum between IR and mm wave radar is called the Terahertz portion of the spectrum. It has the advantage over radar in that optical methods may be able to be used thus reducing the cost and the advantage over IR in that it is absorbed or scattered less by the atmosphere. Systems are now being developed which should permit widespread use of this portion of the spectrum.
A focusing system, such as used on some camera systems, could be used to determine the position of an approaching vehicle when it is at a significant distance away but is too slow to monitor this position just prior to a crash. This is a result of the mechanical motions required to operate the lens focusing system. By itself, it cannot determine the class of the approaching object but when used with a charge coupled, or CMOS, device plus infrared illumination for night vision, and an appropriate pattern recognition system, this becomes possible. Systems based on focusing theory have been discussed above and in the referenced patents which permit a crude distance determination from two camera settings that can be preset. In some cases two imagers can be used for this purpose. A stereo camera based system is another method of getting the distance to the object of interest as discussed above and in the referenced patents and patent applications.
From the above discussion, it can be seen that the addition of sophisticated pattern recognition techniques to any of the standard illumination and/or reception technologies for use in a motor vehicle permits the development of an anticipatory sensor system which can identify and classify an object prior to the actual impact with the vehicle.
FIG. 16 is an exemplary flow diagram of one embodiment of this invention. The blind spot monitor begins by acquiring an image of the blind spot that contains an object to be identified (step 159) and by determining the range to the object (step 160) and outputs range information and image information to a feature extraction routine (step 161). The output from the feature extraction routine is fed into the neural network or other pattern recognition algorithm. The algorithm determines the identity of object (step 162). Once the identity and range of the object is known then the display can be updated (step 163). Using current and recent information, the relative velocity algorithm determines the relative velocity of the object to the host vehicle by differencing or by Doppler techniques (step 164). With the position, velocity and identity of the object in the blind spot known, an appropriate algorithm determines whether it is safe for a lane-changing maneuver (step 165). If the determination is yes, then control is returned to the image collection and ranging activities and a new image and range is determined. If the lane change determination is no, then a determination is made if the turn signal is activated (which would be indicative of the driver's intention to change lanes) (step 166). If yes, then audio and/or visual warnings are activated (step 167). If no, then a determination is made if the operator has begun to change the direction of the vehicle to begin executing a lane change (and simply failed to activate the turn signal) (step 168). If map data is present road curvature can also be taken into account. If the vehicle has begun executing a lane change, then the audio and/or visual warnings are again activated (step 167) and a haptic system begins to exert a torque on the steering wheel to oppose the turning motion of the driver (step 169). Alternately, a vibration can be induced into the steering wheel as a further warning to the operator not to execute a lane change. Following these activities, control is returned to the image acquisition and range determination activities and the process repeats.
The application of anticipatory sensors to frontal impact protection systems is shown in FIG. 17 which is an overhead view of a vehicle 70 about to be impacted in the front by an approaching vehicle 71. In a similar manner as in FIG. 15, a transmitter 72 transmits waves 73 toward vehicle 71. These waves are reflected off of vehicle 71 and received by receiving transducers 74 and 75 positioned on either side of transmitter 72.
FIG. 18A illustrates the front of an automobile 76 and shows preferred locations for transmitting transducer 72 and receiving transducers 74 and 75, i.e., the transmitter 72 below the grill and the receivers 74,75 on each side of the grill. FIG. 18A also illustrates the distinctive features of the vehicle which cause a distinct pattern of reflected waves which will differ from that of a truck 77, for example, as shown in FIG. 18B. In some pattern recognition technologies, the researcher must determine the distinctive features of each object to be recognized and form rules that permit the system to recognize one object from another of a different class. An alternative method is to use artificial neural network technology wherein the identification system is trained to recognize different classes of objects. In this case, a training session is conducted where the network is presented with a variety of objects and told to which class each object belongs. The network then learns from the training session and, providing a sufficient number and diversity of training examples are available, the network is able to categorize other objects which have some differences from those making up the training set of objects. The system is quite robust in that it can still recognize objects as belonging to a particular class even when there are significant differences between the object to be recognized and the objects on which the system was trained.
Once a neural network has been sufficiently trained, it is possible to analyze the network and determine the “rules” which the network evolved. These rules can then sometimes be simplified or generalized and programmed as a fuzzy logic algorithm. Alternately, a neural computer can be programmed and the system implemented on a semiconductor chip as available from Motorola.
The anticipatory sensor system must also be able to determine the distance, approach velocity and trajectory of the impacting object in addition to the class of objects to which it belongs. This is easily done with acoustic systems since the time required for the acoustic waves to travel to the object and back determine its distance based on the speed of sound. With radar and laser systems, the waves usually need to be modulated and the phase change of the modulation determined in order to determine the distance to the object as discussed in U.S. Pat. No. 5,653,462. Since the same distance measurement techniques are used here as in the two above referenced patent applications, they will not be repeated here.
There is a radar chip available that permits the distance determination based on the time required for the radar waves to travel to the object and back. This technology was developed by Amerigon Inc. of Burbank, Calif. and is being considered for other automotive applications such as constant distance cruise control systems and backing-up warning systems.
FIG. 18A is a plan front view of the front of a car showing the headlights, radiator grill, bumper, fenders, windshield, roof and hood and other objects which reflect a particular pattern of waves whether acoustic or electromagnetic. Similarly, FIG. 18B is a plane frontal view of the front of a truck showing the headlights, radiator grill, bumper, fenders, windshield, roof and hood illustrating a significantly different pattern. Neural network pattern recognition techniques using software available from International Scientific Research. of Panama City, Panama can be used to positively classify trucks as a different class of objects from automobiles and further to classify different types of trucks giving the ability to predict accident severity based on truck type and therefore likely mass, as well as velocity. Other software tools are also commercially available for creating neural networks and fuzzy logic systems capable of recognizing patterns of this type.
In FIG. 19, an overhead view of a vehicle 70 about to be impacted in the side by an approaching vehicle 71 in a perpendicular direction is illustrated where infrared radiation 78 is radiating from the front of the striking vehicle 71. An infrared receiver 79 arranged on the side of vehicle 70 receives this radiation for processing as described above.
The anticipatory sensor system described and illustrated herein is mainly used when the pending accident will cause death or serious injury to the occupant. Since the driver will no longer be able to steer or apply the brakes to the vehicle after deployment of an airbag which is sufficiently large to protect him in serious accidents, it is important that this large airbag not be deployed in less serious accidents where the driver's injuries are not severe. Nevertheless, it is still desirable in many cases to provide some airbag protection to the driver. This can be accomplished as shown in FIG. 20 which is a side view with portions cutaway and removed of a dual inflator airbag system, shown generally as 80, with an airbag 69 which in essence comprises two separate airbags 81 and 82 with one airbag 81 lying inside the other airbag 82. An optional variable outflow port or vent 85 is provided in connection with airbag 520 in a manner known in the art. Although a single inflator having a variable inflation rate capability can be used, FIG. 20 illustrates the system using two discrete inflators 83 and 84 which may be triggered independently or together to thereby provide a variable inflation rate of the airbag 69. Inflator 84 and associated airbag 82 are controlled by the anticipatory sensor system described herein and the inflator 83 and associated airbag 81 could also be initiated by the same system. In a less severe accident, inflator 83 can be initiated also by the anticipatory sensor without initiating inflator 84 or, alternately, inflator 83 could be initiated by another sensor system such as described U.S. Pat. No. 5,231,253. Each inflator 83, 84 contains standard materials therefor, e.g., an initiator, a gas propellant.
Thus, the variable inflation rate inflator system for inflating the airbag 69 comprises inflators 83, 84 for producing a gas and directing the gas into the airbag 69, and crash sensors (as described in any of the embodiments herein or otherwise available) for determining that a crash requiring an airbag will occur or is occurring and, upon the making of such a determination, triggering the inflator(s) 83 and/or 84 to produce gas and direct the gas into the airbag 69 to thereby inflate the same at a variable inflation rate, which depends on whether only inflator 83 is triggered, only inflator 84 is triggered or both inflators 83, 84 are triggered (see FIG. 27).
More particularly, the inflator 84 may be associated with an anticipatory crash sensor to be triggered thereby and the inflator 83 may be associated with the anticipatory crash sensor or another different sensor, such as one which detects the crash only after it has occurred. In this manner, inflator 84 will be triggered prior to inflator 83 and inflator 83, if triggered, will supply an additional amount of gas into the airbag 69.
Although the description above is based on the use of two inflators, the same result can be obtained through the use of a variable outflow port or vent 158 from the airbag 69 (additional information about a variable outflow port or vent from the airbag 69 is provided in U.S. Pat. No. 5,748,473 (FIG. 9)). A schematic drawing of an embodiment including a single inflator and a variable outflow port or vent from the airbag is shown in FIG. 28. This has the advantage that only a single inflator is required and the decision as to how much gas to leave in the airbag can be postponed.
As shown in FIG. 28, a first crash sensor 153 is an anticipatory sensor and determines that a crash requiring deployment of the airbag 69 is about to occur and initiates deployment prior to the crash or substantially concurrent with the crash. Thereafter, a second crash sensor 154, which may be an anticipatory crash sensor (possibly even the same as crash sensor 153) or a different type of crash sensor, e.g., a crush sensor or acceleration based crash sensor, provides information about the crash before it occurs or during its occurrence and controls vent control mechanism 157 to adjust the pressure in the airbag. The vent control mechanism 157 may be a valve and control system therefor which is situated or associated with a conduit connected to the outflow port or vent 85 at one end and at an opposite end to any location where the pressure is lowered than in the airbag whereby opening of the valve causes flow of gas from the airbag through the conduit and valve.
Specifically, the vent control mechanism 157 adjusts the flow of gas through the port or vent 85 in the airbag 69 (FIG. 20) to enable removal of a controlled amount of gas from the airbag 69 and/or enable a controlled flow of gas from the airbag 69. In this manner, the airbag 69 can be inflated with the maximum pressure prior to or substantially concurrent with the crash and thereafter, once the actual crash occurs and additional, possibly better, information is known about the severity of the crash, the pressure in the airbag is lowered to be optimal for the particular crash (and optimally in consideration of the position of the occupant at that moment).
In the alternative, the vent control mechanism 157 can be controlled to enable removal of gas from the airbag 69 concurrent with the generation of gas by the inflator 84 (and optionally 83). In this manner, the rate at which gas accumulates in the airbag 69 is controllable since gas is being generated by inflator 84 (and optionally inflator 83, dependent on the anticipated severity of the crash) and removed in a controlled manner via the outflow port or vent 85.
4.1 Positioning Airbags
Referring again to FIG. 20, when the large airbag 82 is inflated from the driver's door, for example, it will attempt to displace the occupant away from the vehicle door. If the seatbelt attachment points do not also move, the occupant will be prevented from moving by the seatbelt and some method is required to introduce slack into the seatbelt or otherwise permit him to move. Such a system is shown in FIG. 21 which is a perspective view of a seatbelt mechanism where a device releases a controlled amount of slack into seatbelt allowing an occupant to be displaced.
The seatbelt spool mechanism incorporating the slack inducer is shown generally as 68 in FIG. 21 and includes a seatbelt 86 only a portion of which is shown, a housing 87 for the spool mechanism, a spool 88 containing several wound layers of seatbelt material 86. Also attached to the spool 88 is a sheave 89 upon which a cable 90 can be wound. Cable 90 can be connected to a piston 92 of an actuator 91. Piston 92 is positioned within a cylinder 94 of the actuator 91 so that a space is defined between a bottom of the cylinder 94 and the piston 92 and is able to move within cylinder 94 as described below.
When the anticipatory sensor system decides to deploy the airbag, it also sends a signal to the seatbelt slack inducer system of FIG. 21. This signal is in the form of an electric current which passes through a wire 96 and is of sufficient magnitude to initiate a pressure generating mechanism for generating a pressure in the space between the piston 92 and the cylinder 94 to force the piston 92 in a direction to cause the sheave 89 to rotate and thus the spool 88 to rotate and unwind the seatbelt therefrom. More specifically, the electric current through wire 96 ignites a squib 97 arranged in connection with a propellant housing 95. Squib 97 in turn ignites propellant 98 situated within housing 95. Propellant 98 burns and produces gas which pressurizes chamber 99 defined in housing 95, which is in fluid communication with the space at a bottom 93 of the cylinder 94 between the cylinder 94 and the piston 92, and pressurizes cylinder 94 below piston 92. When subjected to this pressure, piston 92 is propelled upward within cylinder 94, pulling cable 90 and causing sheave 89 to rotate in the counterclockwise direction as shown in FIG. 21. This rotation causes the spool 88 to also rotate causing the belt 86 to spool off of spool 88 and thereby inducing a controlled amount of slack into the belt and thus permitting the occupant to be displaced to the side.
In some cases, it may not be necessary to control the amount of slack introduced into the seatbelt and a simpler mechanism which releases the seatbelt can be used.
An alternate system is shown in FIG. 22 which is a frontal view of an occupant 100 being restrained by a seatbelt 101 having two anchorage points 102 and 103 on the right side of the driver where the one 102 holding the belt at a point closest to the occupant 100 is released allowing the occupant 100 to be laterally displaced to the left in the figure during the crash. A detail of the release mechanism 102 taken within the circle 22A is shown in FIG. 22A.
The mechanism shown generally as 102 comprises an attachment bolt 111 for attaching the mechanism to the vehicle tunnel sheet-metal 109. Bolt 111 also retains a metal strip 110 connected to member 106. Member 106 is in turn attached to member 108 by means of explosive bolt assembly 105. Member 108 retains the seatbelt 101 by virtue of pin 107 (FIG. 22B). A stop 112 placed on belt 101 prevents the belt from passing through the space between pin 107 and member 108 in the event that the primary anchorage point 103 fails. Upon sensing a side impact crash, a signal is sent through a wire 104 which ignites explosive bolt 105 releasing member 106 from member 108 and thereby inducing a controlled amount of slack into the seatbelt.
In some implementations, the vehicle seat is so designed that in a side impact, it can be displaced or rotated so that both the seat and occupant are moved away from the door. In this case, if the seatbelt is attached to the seat, there is no need to induce slack into the belt as shown in FIG. 23. FIG. 23 is a frontal view of an occupant 115 being restrained by a seatbelt 116 integral with seat 117 so that when seat 117 moves during a crash with the occupant 115, the seatbelt 116 and associated attachments 118, 119, 120 and 121 also move with the seat allowing the occupant 115 to be laterally displaced during the crash.
Various airbag systems have been proposed for protecting occupants in side impacts. Some of these systems are mounted within the vehicle seat and consist of a plurality of airbag modules when both the head and torso need to be protected. An illustration of the use of this module is shown in FIG. 24A, which is a frontal view of an occupant 122 being restrained by a seatbelt 123 and a linear airbag module 124, of the type described in patent application publication US20020101067, including among other things a housing 126 and an inflatable airbag 125 arranged therein and associated inflator. This linear module is mounted by appropriate mounting devices to the side of seat back 127 to protect the entire occupant 122 from his pelvis to his head. An anticipatory sensor may be provided as described above, i.e., one which detects that a side impact requiring deployment of the airbag is required based on data obtained prior to the crash and initiates inflation of the airbag by the inflator in the event a side impact requiring deployment of the airbag is detected prior to the start of the impact.
Airbag module 124 may extend substantially along a vertical length of the seat back 940 as shown, and the airbag 124 in the housing 126 may be attached to the seat-back 127 or integral therewith.
A view of the system of FIG. 24A showing the airbag 125 in the inflated condition is shown in FIG. 24B.
In FIG. 25A, a frontal view of an occupant 128 being restrained by a seatbelt 129 and wherein the seat 131 is displaced toward vehicle center, i.e., away from the side and side door of the vehicle, by deploying airbag 130 is shown. In this case, the seatbelt 129 is attached to the seat 131 as described above with reference to FIG. 23. In this case, rail mechanisms 132 and 133 permit the seat to be displaced away from the door under the force produced by the deploying airbag 130. Rail mechanisms 132,133 may include a first member having a guide channel and a second member having a projection positioned for movement in the guide channel of the first member.
To enable displacement of the seat 131 and thus the occupant 128 away from the airbag-deploying structure, the door in the illustrated embodiment, by the force exerted on the seat 131 upon inflation of the airbag 130, the rail mechanisms 132,133 are preferably oriented in any direction not perpendicular to the deploying direction of the airbag, i.e., not parallel to the side of the vehicle in the illustrated example. Otherwise, if the orientation of the rails mechanisms 132,133 was parallel to the side of the vehicle and the airbag 130 deployed in a direction perpendicular to the side of the vehicle, the seat 131 would not be moved away from the side door. Obviously, to provide for the fastest possible displacement away from the airbag-deploying structure, the rail mechanisms 132,133 are oriented perpendicular to the airbag-deploying structure, which may also be parallel to the deploying direction of the airbag 130.
Thus, for an airbag mounted in the steering wheel or dashboard and designed to deploy in a frontal impact, the rail mechanisms 132,133 would optimally be oriented in the longitudinal direction of the vehicle. For an airbag mounted in the side as shown in FIG. 25A, the rail mechanisms would optimally be oriented in a direction perpendicular to the longitudinal direction of the vehicle.
In FIG. 25B, a frontal view of an occupant 128 being restrained by a seatbelt 129 and wherein the seat 131 is rotated toward vehicle center, i.e., substantially about an axis perpendicular to a horizontal plane of the vehicle, by deploying airbag 130 is shown. In this case, the seatbelt 12 is attached to the seat 131 as described above with reference to FIG. 23. In this case, rail mechanisms 134 and mounting locations 135 permit the seat to be rotated away from the door under the force produced by the deploying airbag 130. This figure is shown with the occupant rotated 90 degrees from initial position, this amount of rotation may be difficult for all vehicles. However, some degree of rotation about the vertical axis is possible in most vehicles. Rail mechanisms 134 may include a first member having a curved guide channel and a second member having a projection positioned for a curving or rotational movement in the guide channel of the first member.
As shown in FIG. 25B, the seat 131 is rotated in a clockwise direction so that the occupant is facing inward during the rotation. The rail mechanism 134 can be designed to rotate the seat 131 counterclockwise as well as along any rotational path. For example, in a frontal impact, it might be desirable to rotate the occupant toward the adjacent side door to enable the occupant to exit the vehicle via the side door and/or be extracted from the vehicle via the side door. Otherwise, if the occupant were to be rotated inward, the seat back would be interposed between the occupant and the side door and might hinder egress from the vehicle and extraction of the occupant from the vehicle after the crash.
In an alternate case where there is sufficient space for the occupant's legs and feet, the seat 131 can be rotated as shown in FIG. 25C, i.e., substantially about an axis oriented in a longitudinal direction of the vehicle. The rotating mechanism comprises a hinged assembly of two plates 136 and 137, with plate 136 attached to the vehicle floorpan and plate 137 attached to the vehicle seat 131. The two plates are held together by a suitable clamp 138 which is released by the sensor at the same time the airbag is deployed.
Other means for tilting the seat 131 or enabling rotation of the seat 131 about the vehicle yaw axis or roll axis are also envisioned to be within the scope of the invention.
The displacement of the seat 131 by the force exerted by the airbag upon its inflation or deployment is thus very useful for increasing the distance between the occupant and the site of the impact, whether it is a side impact, frontal impact or even a rear-impact.
Displacement of the seat 131 could also be useful in rollover situations where the occupant could benefit from such a rotation or displacement depending on the nature of the rollover. Such a system could aid in preventing the occupant's head or other body part from being partially ejected out of the passenger compartment. Thus, a rollover sensor, which can be one or more gyroscopes and/or accelerometers or even an IMU (inertial measurement unit), could replace the crash sensor for this purpose. Upon detection of a rollover, an action could be taken to inflate an airbag and enable movement of the seat when the force exerted by the inflation of the airbag is effective on the seat. One or more of the seat displacement enabling system could be incorporated into the vehicle so that one or more of these systems can be activated upon the detection of a rollover, depending on which motion of the seat and occupant would best benefit the occupant.
Many of the techniques disclosed above will not work well for some of today's small vehicles. They are more applicable in vans, sport utility vehicles, some small trucks and some minivans with some modifications. For these and other vehicles, an externally deployed airbag may be an alternate solution or both can be used together.
4.2 Exterior Airbags
Once an anticipatory sensor system is in place, it becomes possible to consider deployment of an airbag external to the vehicle. This possibility has appeared in the automobile safety literature in the past but it has not been practical until the impacting object can be identified and/or an assessment of the probable severity of the accident made. For prior art systems, it has not been possible to differentiate between a plastic sand-filled construction barrier or a cardboard box, for example, neither of which would result in a serious accident (and thus airbag deployment would not be required) and a concrete pillar, tree or wall which would likely result in a serious accident (and thus airbag deployment would be required). With the development of the pattern recognition systems described herein, and in the above referenced patents and patent applications, this problem has been solved and the use of an external airbag now becomes feasible.
Assessment of the probable severity of the impact is preferably accomplished using one or more of the pattern recognition techniques disclosed herein, whereby the identity, size or another property of the object about to impact the vehicle (or with which the vehicle is about to impact) is determined using the pattern recognition technique and the identification or determination of the object's size is considered before initiating deployment of the airbag. In this manner, upon appropriate training of the pattern recognition algorithm, if the vehicle is about to strike a large cardboard box, it will be identified as such and airbag deployment will not occur. On the other hand, if the vehicle is about to strike a large truck, it will be identified as such and airbag deployment will occur. In the prior art, no such differentiation was made about the object involved in the impact based on remote sensing, i.e., sensing prior to impact.
Such a system adapted for side impact protection is shown in FIG. 26A which is a perspective view with portions cutaway and removed of a vehicle 140 about to be impacted in the side by another vehicle 141. An airbag module is shown generally as 146 mounted to the side door of the vehicle 140 prior to inflation of an airbag 147 arranged in the airbag module 146. A portion of the side door of vehicle 140 has been cutaway to permit viewing of the airbag module 146. The vehicle 140 contains a strong support beam 144 arranged in a longitudinal direction of the vehicle at least partially within the side door(s) 142 and which provides a reaction surface along with the vehicle door 142 for the airbag. Upon initiation by the anticipatory sensor, a deployment door, not shown, is opened in an external door panel 143 by any of a number of methods such as pyrotechnically, permitting the airbag 147 to emerge from the vehicle door 142 as shown in FIG. 26B, the airbag 147 being inflated by an inflator responsive to the detection by the anticipatory sensor that a side impact requiring deployment of the airbag is required.
Through a system such as illustrated in FIGS. 26A and 26B, the accident can be substantially cushioned prior to engagement between the vehicle and the impacting object. By this technique, an even greater protection can be afforded the occupant especially if an internal airbag is also used. This has the further advantage that the occupant may not have to be displaced from behind the steering wheel and thus the risk to causing an accident is greatly reduced. It also may be the only system which will work with some of today's small vehicles. The anticipatory sensor system could determine whether the impact is one which requires deployment of only the external airbag 147 or one which requires deployment of both the internal airbag and the external airbag 147.
Although the description of FIGS. 26A and 26B relates to side impact protection, it is understood that the same concept can be used for frontal impacts and rear impacts and rollover situations. That is, the location of the airbag 147 is not limited to locations along the side of the vehicle, nor to the side door.
An anticipatory sensor system can thus be installed all around the vehicle, with multiple externally deployable airbags, whereby in use, when a determination is made that an object is about to impact the vehicle, only the airbag(s) which will inflate between the vehicle and the object, and which will cushion the impact, is/are inflated.
For example, FIGS. 29A and 29B show an externally deployable airbag mounted at the front of a vehicle so as to provide frontal impact protection. The airbag may be mounted in a housing or module in and/or proximate the bumper, fender, grille, or other part at the front of the vehicle. By using anticipatory sensing and/or exterior object identification as discussed above, the airbag is deployed prior to or at the moment of impact.
FIGS. 30A and 30B show an externally deployable airbag mounted at the rear of a vehicle so as to provide rear impact protection. The airbag may be mounted in a housing or module in and/or proximate the bumper or another part at the rear of the vehicle. By using anticipatory sensing and/or exterior object identification as discussed above, the airbag is deployed prior to or at the moment of impact.
4.3 Pedestrian Protection
FIGS. 31A and 31B show an externally deployable airbag mounted at the front of a vehicle for a situation where pedestrian protection is obtained. The airbag may be mounted in a housing or module in and/or proximate the bumper, fender, grille, or other part at the front of the vehicle. By using anticipatory sensing and/or exterior object identification as discussed above, the airbag is deployed prior to or at the moment of impact to protect the pedestrian. It can be seen by comparing FIG. 29B and FIG. 31B that the airbag for pedestrian protection deploys over the hood of the vehicle instead of in front of the vehicle. In a similar manner, an airbag for pedestrian impact protection at the rear of a vehicle would be arranged to deploy over the trunk instead of rearward as shown in FIG. 30B.
In this embodiment, the anticipatory sensor system can be designed to sense an approaching pedestrian or animal and deploy the airbag to cushion the pedestrian's or animal's impact against the vehicle.
It is envisioned that the features of the side impact protection systems, rear impact protection systems, frontal impact protection systems, and pedestrian impact protection systems can be used interchangeably to the extent possible. Thus, features of the side impact protection systems can be used for rear, frontal and pedestrian impact protection.
4.4 Positioning of Out-of-Position Occupants
In another embodiment of the invention using an anticipatory sensor system, a deploying airbag is used to position the occupant. That is, an airbag is arranged and designed to move only a part of the occupant, not necessarily the seat, so as to make room for deployment of another airbag. For example, a shoulder or thorax airbag could be deployed based on a determination from an anticipatory sensor system that a crash is imminent and a determination from an interior monitoring system that the occupant's head is resting against the window. The deploying shoulder or thorax airbag would serve to push the occupant's head away from the window, making room for the deployment of a side curtain airbag between the window and the person's head. Such positioning airbags could be strategically arranged in the vehicle to move different parts of an occupant in a specific direction and then deployed based on the position the occupant is in prior to the impact to change the occupant's status of “out-of-position” vis-à-vis airbag deployment to “in-position”.
An example of the use of positioning airbags in accordance with the invention is shown in FIGS. 32A, 32B and 32C wherein a passenger is shown leaning against a door in FIG. 32A, a positioning airbag deploys from the door to move the passenger away from the door as shown in FIG. 32B and a side curtain airbag is deployed, e.g., from a location above the window, when the passenger has been moved away from the door as shown in FIG. 32C. Ideally, the passenger or a part thereof would be moved a sufficient distance to enable effective deployment of the side curtain airbag while preventing injury.
Using a positioning airbag, the positioning airbag is preferably deployed before the main airbag or side curtain airbag. Deployment of the positioning airbag could be initiated based on anticipatory sensing of an object about to impact the vehicle, and/or in conjunction with an interior monitoring system or occupant position sensor which would sense the position of the occupant or a part thereof and determine the need to move the occupant or a part thereof to enable deployment of the main airbag or side curtain airbag, or at least to make the deployment more effective. Deployment of the positioning airbag(s) could also be based on an actual detection of a crash involving the vehicle by crush-based sensors or acceleration-based sensors and the like. Determination of the position of the occupant can lead to assessment of a situation when the occupant is out-of-position for deployment and must be moved into a better position for deployment of the main or side curtain airbag. A “better” position for deployment being a position in which the occupant is able to receive more of the benefits of the protective cushion and/or movement prevention provided by the main or side curtain airbag.
The use of positioning airbags is also particularly suited for rollovers. In a rollover situation, a vehicle 170 can move sideways toward a curb or highway barrier 171 (FIG. 33A) and then strike the barrier 171 (FIG. 33B). Upon impact with the barrier 171, the driver 172 is forced toward the driver-side window 173 while the vehicle 170 begins to rollover. At this time, as shown in FIG. 33C, the side curtain airbag 174 deploys downward. However, since the driver 172 is against the window 173, the side curtain airbag 174 may actually deploy inward of the driver 172 thereby can trap the driver 172 between the side curtain airbag 174 and the window 173. Typically the window 173 breaks so that the head of the driver 172 may actually be forced through the broken window. When the vehicle 170 completes the rollover, the driver 172 is forced against the ground and may be seriously injured if not killed (FIG. 33D).
To remedy this situation, the invention contemplates the use of one or more positioning airbags. As such, as shown in FIG. 34B, when the driver 172 is detected to be against the window 173 or simply displaced from a position in which the side curtain airbag 174 will be properly deployed, a positioning airbag 175 is deployed. Such detection of the position of the occupant may be made by any type of occupant sensor including but not limited to a proximity sensor arranged in the door. As shown in FIG. 34B, the positioning airbag 175 is arranged in a door of the vehicle 170 and deploys inward. The positioning airbag 175 may also be arranged in the side of the seat or in the side of the vehicle other than in a door. Also, the positioning airbag 175 can be controlled to deploy whenever deployment of the side curtain airbag 174 is initiated. That is, it is possible to provide a sensor for detecting when side curtain airbag 174 will deploy (for example a rollover sensor) and once such deployment is authorized, the positioning airbag 175 will be deployed prior to deployment of the side curtain airbag 174 to ensure that the driver is properly positioned (See FIGS. 34C and 34D). In this case, the activation mechanism of the positioning airbag 175 is coupled to the control device of the side curtain airbag 174.
Although a side curtain airbag has been illustrated in the various figures herein, this same invention applies when an inflatable tube or tubular airbag, such as manufactured by Simula Inc. of Arizona, is used for retention of an occupants head within the vehicle. Thus, for the purposes herein, a side curtain airbag will encompass such inflatable tube or tubular airbags or equivalent. Similarly, although they have not been widely used up until now, other systems employing nets have been proposed for this purpose and they are also contemplated by this invention.
In one typical embodiment, the positioning airbag will always be deployed in rollover accidents when the curtain or tubular airbag is deployed and an occupant position sensor is not used. Similarly, the side curtain or tubular airbag is also usually deployed even in side impacts where there is no rollover as it provides protection against the occupant's head striking the intruding vehicle. There is even a strong motivation for deploying both side positioning and curtain or tubular airbags for frontal impacts as control over the position and motion of the occupant is improved.
Finally, although it is desirable to deploy the positioning airbag first, in many cases both airbags are deployed at the same time and the fact that the positioning airbag will deploy more rapidly is relied on to prevent the entrapment of the occupant's head outside of the window. The flow of gas into the curtain airbag can be controlled to facilitate this effect.
In a frontal crash when a frontal protection airbag is used, the direction of deployment of the positioning airbag would be substantially perpendicular to the direction of deployment of the frontal airbag. That is, the positioning airbag would deploy in a direction away from the door laterally across the vehicle whereas the main airbag would deployed in a longitudinal direction of the vehicle. The positioning airbag would thus move the occupant laterally to obtain the benefits of the deployment of the frontal airbag. However, the angle between the deployment direction of the positioning airbag and the deployment direction of main or side curtain airbag can vary. In fact, it is conceivable that the deployment directions are the same whereby if an occupant is too close to the deployment door or location of the main airbag, then a smaller positioning airbag is deploy to push the occupant away from the deployment door and only once the occupant is sufficiently distant from the deployment location is the main airbag deployed. Monitoring of the position of the occupant is useful to determine when the positioning airbag need to be deployed and if and when the occupant is moved a sufficient distance by the deployment of the positioning airbag so as to be positioned in a proper position for deployment of the main or side curtain airbag. The rate of deployment of the positioning airbag and the amount of inflation gas used to deploy the airbag can be varied depending on the size and position of the occupant (as determined by occupant sensors for example) and the severity of the crash.
The timing of the deployments of the positioning airbag and main airbag, or the positioning airbag and side curtain airbag, can take into account the distance the occupant must be moved, i.e., the position of the occupant. This can ensure that the occupant is not moved too far by the positioning airbag out of the range of protection provided by the main airbag. The timing can thus be based on the position and/or weight of the occupant. The timing of the deployments can also or alternatively be based on the characteristics or properties of the occupant, i.e., the morphology of the occupant. For example, different deployment scenarios can be used depending on the weight of the occupant since a lighter occupant would move faster than a heavier occupant.
The rate of deployment of the main or side curtain airbag can also be varied so that it deploys more slowly than the positioning airbag. As such, the positioning airbag will have its positioning effect first and only thereafter will the main or side curtain airbag have its protective effect. The rate of deployment of the airbags can be varied in addition to the timing of the deployments.
Although the use of positioning airbags is described above with reference to FIGS. 34A-34D for a driver, it is understood that such positioning airbag can be used for each seating location in the vehicle. Also, one airbag can be used for multiple seating locations, for example, seating locations on the same side of the vehicle.
The manner in which the positioning airbag is deployed is illustrated in FIG. 35 wherein the first step is to detect a rollover or other crash situation at 240. Such detection may be based on anticipatory crash sensing. The occupant's position (present or future) may then be determined or monitored at 241. For multiple occupants, the position of each occupant can be determined at that time or it is conceivable that the occupant's position at a set time in the future is extrapolated, for example, based on the occupant's current position and velocity, the occupant's position in the immediate future can be calculated using the equation that the future position equals the current position plus the velocity times the time differential. A determination is made at 242 whether the occupant is “out-of-position” which in the rollover situation would be too close to the window. If not, then the side curtain airbag is deployed at 243. If yes, a positioning airbag is deployed at 244 to move the occupant into an appropriate position for deployment of the side curtain airbag. Optionally, the occupant's position can be determined after deployment of the positioning airbag at 245 or extrapolated based on the imparted velocity to the occupant from the deploying positioning airbag. If the position of the occupant is proper for deployment of the side curtain airbag or will be proper for the deployment of the side curtain airbag, then the side curtain airbag is deployed at 243.
Positioning airbags can be arranged at different locations throughout the vehicle with each one designed to move one or more occupants in a desired direction. A control unit for the positioning airbags, which may be a processor coupled to a crash sensor system (anticipatory or other) and occupant position determining system, determines which positioning airbag(s) are to be deployed based on the position of the occupant(s).
The general components of an apparatus for deploying multiple airbags in accordance with the invention are shown schematically in FIG. 36. A crash and/or rollover sensor system 180 is arranged on the vehicle and may include one or more anticipatory crash sensors, crush crash sensors, acceleration-based crash sensors or rollover sensors based on gyroscope(s), an IMU or angle sensors. An occupant position/velocity sensor system 181 is arranged on the vehicle to monitor the presence and position of the occupants and optionally determine the velocity of the occupants. The sensor system 181 can be any known system in the prior art including those disclosed in the U.S. patent documents referenced above. Sensor system 181 can also include sensors which measure a morphological characteristic or property of the occupant such as the occupant's weight. The crash sensor system 180 and occupant sensor system 181 are coupled to a processor/control unit 182. Control unit 182 receives input from the crash sensor system 180 as to an expected crash involving the vehicle (when the crash sensor system 180 includes an anticipatory sensor) or an actual crash or rollover involving the vehicle. Control unit 182 determines which protective airbags need to be deployed, if any, to protect the occupants. Such protective airbags include the side curtain airbag on the left side of the vehicle 183, the side curtain airbag on the right side of the vehicle 184, the front airbag on the left side of the vehicle 185, the front airbag on the right side of the vehicle 186, and others. Control unit 182 also determines whether any of the positioning airbags 1-4 (elements 187A-187D) need to be deployed prior to and/or in conjunction with the deployment of the protective airbags. Although generally the positioning airbags are deployed prior to the deployment of the protective airbags in order to properly position an occupant, the positioning airbags could be deployed whenever the vehicle experiences a crash or rollover to provide some added cushioning. Positioning airbag 1 could be associated with the side curtain airbag on the left side of the vehicle and effective to move the occupant(s) away from the left side of the vehicle. Positioning airbag 2 could be associated with the side curtain airbag on the right side of the vehicle and effective to move the occupant(s) away from the right side of the vehicle. Positioning airbags 3 and 4 would serve to deploy to position the occupants for deployment of the respective frontal airbags.
Control unit 182 can determine the timing of the deployment of the positioning airbag and associated protective airbag, i.e., the time differential between initiation of the inflation which will be optimum to allow the occupant time to be moved by the positioning airbag into position to be protected by the protective airbag. Control unit 182 can also determine the rate of inflation of the positioning and protective airbags, when such airbags are provided with the capability of variable inflation rates. In this case, the protective airbag may be deployed at the same time as the positioning airbag (or possibly even before) but the protective airbag inflates more slowly than the positioning airbag. Control unit 182 can also factor in the morphology of the occupant to be protected when determining the inflation parameters, i.e., the timing difference and rate of inflation. This is useful since weight of the occupant affects the occupant's movement, i.e., a heavier occupant will be moved more slowly than a lighter occupant. In some cases more gas will be allowed to flow into the airbag for heavier people than for lighter people.
5. Overtaking Problem
FIG. 37 illustrates a lane-changing problem on a two-lane road with a single lane in each direction wherein one vehicle 46 in travel lane 62 wants to pass or overtake a slower moving vehicle 47 in front of it. A system that addresses this problem is most applicable for two-lane roads as opposed to a blind spot monitoring system described above wherein the road usually has multiple lanes in each direction and a driver wants to change lanes and must be concerned with another vehicle in an adjacent, same-direction of travel lane. Since the majority of roads on which a vehicle travels are typically not multi-lane, a system is also desirable which will aid the driver in determining whether it is unsafe to enter an oncoming lane in order to pass one or more vehicles in the traveling lane, and once having initiating the passing maneuver, whether it is safe to complete the maneuver. The blind spot system described in any of its configurations above will prevent the driver from initiating a passing operation when an overtaking vehicle is in the blind spot, i.e., coming up on it from behind. The remainder of a lane change operation is left to the judgment and facilities of the driver. The system can additionally or alternatively be configured to assess the presence of a vehicle in an oncoming lane (opposite direction of travel) and prevent a lane change for the purpose of a vehicle overtaking if such a lane change will likely result in an accident with an oncoming vehicle.
In FIG. 37, the driver of a vehicle 46 in lane 62 wants to enter into the oncoming lane 64 to pass or over-take vehicle 47. However, the driver of vehicle 46 must account for the possibility of vehicle 45, e.g., its relative and absolute position and velocity, and if vehicle 46 attempts this lane change under unsuitable conditions, an accident with vehicle 45 may result. Using the teachings herein, the driver of vehicle 46 will be made aware through a visual display and/or through warning signals, optical, audio and/or haptic, should the driver attempt to execute such an overtaking action when it is determined not to be safe. The driver may be made aware of the presence of the vehicle 45 upon activation of the turn signal, upon detection of the beginning of the lane change as reflected in the turning of the steering wheel or front wheels of the vehicle and/or by the presence of an icon showing the vehicle 45 in the display 30, 31.
Referring now to FIG. 38, a system 208 in accordance with the invention that addresses, among other situations, a vehicle overtaking problem on a two lane road, includes a system 210 that determines the driver's visibility distance. This visibility distance can be limited by factors including the topography of the roadway on which the vehicle 46 is travelling, the eyesight of the driver of the vehicle 46, and atmospheric conditions.
Visibility distance determination often requires knowledge of road topography which can be obtained from an on-board and/or Internet-accessible map database 212. In the latter case, the topographical information from the database 212 may be provided to the vehicle via a communications link when the database 212 is remotely situated. This topographical information database 212 should contain sufficient topographical information about the road and its surroundings, such as information about road curvature and elevation information, as well as other information necessary to derive visibility distance. With this knowledge, a calculation using a computer program in a processor 214 included in or associated with the system 210 can be made as to the visibility distance during daylight and under clear atmospheric conditions.
Atmospheric condition sensors 216 may be included in the system 210 to assess the atmospheric conditions and/or atmospheric conditions may be provided by a database 218 or through a wireless connection to a remote source 220 of atmospheric condition information. The atmospheric condition information may be provided by the database 218 or remote source 220 based on the location of the vehicle, e.g., in response to the vehicle providing its location from an on-board GPS system to the database 218 or remote source 220. Atmospheric conditions may also be transmitted by infrastructure and received by a communications system on the vehicle.
For nighttime driving, reliance will need to be based on the assumption that the headlights of the oncoming vehicle 45 can be observed and thus the visibility distance calculation under clear atmospheric conditions can also be made. The visibility distance in poor atmospheric conditions such as with the presence of smog, fog, smoke, rain or snow, can be determined by the backscatter from a vehicle illumination system 222, which may be part of the visibility distance determining system 210.
The eyesight of the driver is not easy to quantify for the purpose of the visibility distance determining system 210 considering it when determining the visibility distance of the driver. In one embodiment, it may be assumed that the driver has 20/20 vision, natural or corrected. This is not always the case. In other embodiments, the driver's eyesight may be disregarded as a factor in the determination of the visibility distance.
If the visibility distance determining system 210 includes a camera 224 that determines significant backscatter reflections are obtained at distances less than the map calculated visibility distance, then the driver can be warned that visibility is limited. This will require a modification to the map-calculated visibility distance. The calculation of the visibility distance based on backscatter is described in the prior art, for example, U.S. patent application Ser. No. 13/686,862 filed Nov. 27, 2012, incorporated by reference herein.
There are different techniques for the visibility distance determining system 210 to determine the visibility of the driver. In one implementation, a plot of the percentage of atmospheric reflections versus distance is obtained and an arbitrarily value, such as 50%, is selected as the definition of the “visibility distance” so that by accessing the plot, the location forward from the vehicle at which 50% of the total reflection has occurred is determined. This can be done using range gating. The distance of reflected light from the point of light emission to the point where 50% of the light has been reflected is then the visibility range gate.
An initial pulse of visible light is projected forward from the vehicle and the total reflected light (RLT) is measured. A second light pulse is then projected and a range gate is used to capture the light reflected from immediately in front of the vehicle and a distance such as 10 meters (RL10). If less than 50% of the light which was measured in RL10 than is present in RFT, then the range gate distance is increased and a new light pulse emitted and a new amount of reflected light measured. This process is continued until the range is determined when 50% of total reflected light (RFT) is obtained and the visibility distance is thereby determined to be this distance. Naturally, a different criterion than 50% can be used to establish the “visibility distance” which is thus an arbitrary definition.
Range gating can be accomplished using Kerr or Pokel cells or other methods known to those skilled in the art.
System 208 also includes a lidar or camera system 226, preferably with an associated pattern recognition system 228, that is capable of acquiring images and measuring the distance to objects, such as vehicles, in front of the vehicle and that have been detected in the acquired images. Referred to in the following simply as a camera system 226, the camera system 226 is positioned to obtain images of an area in front of the vehicle 46, including those areas to the side of the vehicle 46, i.e., diagonally forward from the vehicle 46. Camera system 226 is configured to obtain images either continually or only when the presence of a vehicle 47 in front of the vehicle 46 is detected. In the latter case, processing of images is reduced to only those times when the overtaking problem may arise. The pattern recognition system 228 is capable of processing the images or data derived therefrom into an indication of the presence of a vehicle and the distance between the oncoming vehicle and the vehicle or the velocity of the oncoming vehicle.
When the driver begins to execute a passing maneuver, a processor 230 that receives the determined visibility distance from the visibility distance determining system 210 and images from the vehicle camera system 226, or data about objects in front of the vehicle derived from those images by the camera system 226 or the pattern recognition system 228 therein, will determine the presence of a road-occupying item in the passing lane, e.g., vehicle 45, that will affect the ability to successfully undertake the passing maneuver. Beginning of execution of the passing maneuver may be determined by monitoring the steering wheel, turn signal, movement of the vehicle, as described above. If such a road-occupying item is determined to be present by processor 230, the driver is warned that the passing maneuver should be aborted, for example, by a warning system 232. If not, the driver is able to begin the passing maneuver.
However, once the passing maneuver has begun and the vehicle 46 is in the lane 64 (see FIG. 37), the camera system 226 will continue to obtain images of the area directly in front of the vehicle 46 and the processor 230 will process the obtained images to determine the presence of a sufficiently long spot in front of the vehicle(s) 47 to be passed to which the passing vehicle 46 can proceed. Information about the vehicle 47 being passed may also be obtained and considered in this determination. In this situation, vehicle 47 may be in the blind spot of vehicle 46 as a result of vehicle 46 passing vehicle 47, and thus the blind spot monitoring system described above may be used to obtain information about vehicle 47.
The processor 230 then determines the distance to that spot and the minimum required velocity and acceleration needed for the vehicle 46 to travel to that spot within the visibility distance, assuming the movement of vehicle 47 is not significantly changed. To aid in this determination, the acceleration of the vehicle 46 is then measured, preferably using an accelerometer 234, which is part of the system. This accelerometer 234 can determine the acceleration imparted to the vehicle 46 by the driver and calculate whether this is sufficient to allow the vehicle 46 to travel to the chosen spot within the visibility distance. If the acceleration is insufficient, then the system 208 must instruct the driver to either increase the acceleration or to abort the passing operation, e.g., via warning system 232, and return the vehicle 46 to its pre-passing initiation position.
This system 208 will thus include a warning system 232 that notifies or informs the driver of a vehicle 46 if a passing maneuver is unsafe to initiate and optionally whether it is unsafe to complete once begun, rather than a system that tells him that it is safe to pass. As long as the driver is responsible for executing the procedure, the system 208, as in the blind spot detection case, cannot inform the driver that it is safe to perform the procedure. Thus, it is a system reactive to the actions of the driver.
In some embodiments of the invention, a fixed indication of the visibility of the driver may be used, e.g., it is assumed that the visibility is normal. In such embodiments, map data may be used to determine whether a warning needs to be provided to a driver when an object travelling in the direction opposite to the direction of travel of the vehicle restricts movement of the vehicle. Map data may be used in combination with information about objects in obtained images including distance between the vehicle and objects travelling in a direction opposite to the direction of travel of the vehicle. The derived information is analyzed in combination with the map data by a processor to determine whether a warning needs to be activated when the driver begins the passing maneuver, as well as preferably when the driver is in the adjacent lane and seeks to complete the passing maneuver.
A driving monitoring system for a vehicle for this embodiment may include a database containing map data, whether entirely resident on the vehicle or only partly resident on the vehicle and partly resident at one or more off-vehicle locations, such as in the “cloud”, and an image obtaining system oriented to obtain images of an area in front of the vehicle and derive information about objects in the obtained images including distance between the vehicle and objects travelling in a direction opposite to the direction of travel of the vehicle, using for example, an on-board processor. The system also includes a warning system that, based on the map data retrieved based on the position of the vehicle and the information about objects travelling in a direction opposite to the direction of travel of the vehicle, warns a driver when an object travelling in the direction opposite to the direction of travel of the vehicle restricts movement of the vehicle.
The invention also encompasses a computer program resident on the non-transitory computer readable media in the vehicle and that is configured to receive input about visibility conditions for a road on which the vehicle is travelling, which may include topographical conditions of the road on which a vehicle is travelling and/or atmospheric conditions, and provide an indication of the visibility of a driver of the vehicle. The computer program also receives input about objects in an adjacent travel lane, which may include objects travelling in a direction opposite to the direction of travel of the vehicle, i.e., in the other lane of a two lane road. The computer program is also configured to monitor vehicular components, including the steering wheel, turn signal lever or indicator and tires, by receiving input from sensors associated therewith in order to determine when the driver is attempting to change lanes into the adjacent lane. At this time, the computer program processes the received input, using a processor that executes the computer program, in order to determine whether entry into the adjacent lane is safe. If so, no action is taken. If not, the computer program is configured to direct a warning system to activate a warning, to hopefully prevent the unsafe entry into the adjacent lane. Thereafter, the computer program is further configured to continue to receive input about the objects in the adjacent travel lane, as well as information about vehicle being passed, and information about the movement of the vehicle, to determine whether the vehicle can safely return to its original travel lane. If so, no action is taken. If not, the computer program is configured to direct a warning system to activate a warning, to hopefully prevent unsafe re-entry into the adjacent lane.
6. Summary
The inventions described above are, of course, susceptible to many variations, combinations of disclosed components, modifications and changes, all of which are within the skill of those practicing the art. It should be understood that all such variations, modifications and changes are within the spirit and scope of the inventions and of the appended claims. Similarly, it will be understood that applicants intend to cover and claim all changes, modifications and variations of the examples of the preferred embodiments of the invention herein disclosed for the purpose of illustration which do not constitute departures from the spirit and scope of the present invention as claimed.
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.

## Claims

1. A driving monitoring system for a vehicle, comprising:
a visibility determining system that provides an indication of the visibility of a driver of the vehicle;
an image obtaining system oriented to obtain images of an area in front of the vehicle and derive information about an object in the obtained images including distance between the vehicle and the object; and
a warning system that, based at least in part on the indication of the visibility of the driver provided by said visibility determining system, the distance between the vehicle and the object derived by said image obtaining system, and movement of the vehicle, warns a driver when a driving maneuver should be aborted.

2. The system of claim 1, wherein the object is at least partially obstructed from the view of the driver.

3. The system of claim 1, wherein said visibility determining system is configured to consider topography of a road the vehicle is travelling on when providing the indication of the visibility of the driver.

4. The system of claim 3, wherein said visibility determining system is configured to access a database of topographical information to obtain information about the topography of the road the vehicle is travelling on.

5. The system of claim 4, wherein said topographical information database is arranged partly on the vehicle.

6. The system of claim 4, wherein said topographical information database is arranged partly at a site off of the vehicle and provided to the vehicle via a communications link.

7. The system of claim 1, wherein said visibility determining system is configured to consider atmospheric conditions around the vehicle when providing the indication of the visibility of the driver.

8. The system of claim 7, further comprising on-board vehicle sensors configured to obtain atmospheric condition information.

9. The system of claim 7, wherein said visibility determining system is configured to access a database of atmospheric condition information to obtain information about the atmospheric conditions around the vehicle.

10. The system of claim 1, wherein said visibility determining system comprises a vehicle illumination system and is configured to determine the visibility in consideration of backscatter from said vehicle illumination system.

11. The system of claim 1, wherein said image obtaining system comprises a lidar or camera system.

12. The system of claim 1, further comprising a processor coupled to said visibility determining system, said image obtaining system and said warning system and that controls said warning system based on the indication of the visibility of the driver provided by said visibility determining system and the distance between the vehicle and the object derived by said image obtaining system.

13. A method for monitoring driving of a vehicle, comprising:
obtaining an indication of visibility of a driver of the vehicle;
obtaining images of an area in front of the vehicle using an image acquiring system;
deriving, using a processor, information about an object in the obtained images including distance between the vehicle and the object; and
warning a driver via a warning system based at least in part on the obtained indication of the visibility of the driver, the distance between the vehicle and the object, and movement of the vehicle, when a driving maneuver should be aborted.

14. The method of claim 13, wherein the object is at least partially obstructed from the view of the driver.

15. The method of claim 13, wherein the step of obtaining an indication of the visibility of the driver comprises obtaining topographical information about a road the vehicle is travelling on.

16. The method of claim 15, wherein the topographical information is obtained from an off-vehicle database.

17. The method of claim 13, wherein the step of obtaining an indication of the visibility of the driver comprises obtaining information about atmospheric conditions around the vehicle.

18. The method of claim 17, wherein the information about atmospheric conditions is obtained by on-board vehicle sensors.

19. The method of claim 17, wherein the information about atmospheric conditions is obtained by access to an off-vehicle database of atmospheric condition information.

20. The method of claim 13, wherein the step of obtaining an indication of the visibility of the driver comprises:
obtaining topographical information about a road the vehicle is travelling on;
obtaining information about atmospheric conditions around the vehicle; and
assessing visibility in view of the obtained topographical information and information about atmospheric conditions in order to provide the indication of the visibility of the driver.