ACCIDENTS

The present invention relates to the field of traffic safety. More particularly, the invention relates to an apparatus for providing alerts for avoiding car accidents, resulting from violations of maintaining a minimum headway, falling asleep or losing concentration.

T_nnVymii¾d of the Invention

Maintaining a safe headway between a moving vehicle and the next vehicle ahead is a critical cognitive task. Crashes due to insufficient vehicle headway, account for a significant portion of all crashes - over 29% in the United States. In many cases, violations of maintaining a minimum headway cause chain collisions, in which many vehicles are involved. Such chain collisions happen since, normally, a driver who decided to stop activates the braking lights only after pressing the braking pedal and starting braking the vehicle. As a result, the driver in a car behind (the "following vehicle") gets a visual alert relatively too late (depending on the driving speed), since his reaction time (the time it takes from getting the alert until pressing the braking pedal and starting braking the following vehicle) is about 0.75 Sec. If for example, the car speed is 90 Km/h, during the reaction time the following vehicle moves 18.75 m. This distance is of course subtracted from the total braking distance and therefore, collision is unavoidable.

Also, many accidents are caused by drivers who drift from the center of their movement lane and enter other lanes of even passing the road shoulders. Therefore, a system which is capable of identifying and preventing such risky scenarios is highly desired. US 2015/0302606 discloses a system for providing an indication of a possible collision between a vehicle and an object, which comprises a processing device configured to receive a plurality of images from a camera and identify the object and a lane marking in the plurality of images. The plurality of images are used to determine information indicative of movement of the object and a lane position associated with the object. The processing device determines whether the vehicle and the object are on collision course based on the information indicative of movement of the object and based on the lane position associated with the object.

All the methods described above, however, have not yet provided satisfactory solutions to the problem of detecting dangerous scenarios of impending collisions between vehicles or between a vehicle and an object (which is considered to be an obstacle).

It is therefore an object of the present invention to provide a method and apparatus for continuously and automatically detecting dangerous scenarios of impending collisions between vehicles or between a vehicle and an object, due to violations in maintaining a minimum headway or due to unawareness.

Other objects and advantages of this invention will become apparent as the description proceeds. finmnmry of the Invention

The present invention is directed to a vehicular apparatus to be installed on a vehicle, for increasing the safety of driving, which comprises:

a) one or more monitoring systems, each of which consisting of horizontally or vertically deployed 2-D cameras with an overlapping part of their field of view and being capable of providing effective three- dimensional (3-D) data, based on image analysis of the overlapping field of view, which is aimed to a desired direction; b) a processor for analyzing the data in real time and providing an accurate estimation of the distance, size, movement direction and speed of any object (such as a pedestrian or a stationary article) within the overlapping field of view;

c) an alert circuitry, activated by the processor, for providing alerts to the driver of the vehicle or to drivers of other vehicles being or moving in the vicinity of the vehicle, regarding an impending risk of collision with objects or other vehicles; and

d) a transmitter for wireless transmission of the alerts.

The vehicular apparatus may comprise:

a) a first monitoring system installed on the vehicle and directed forwardly;

b) a second monitoring system installed on the vehicle and directed rearward,

wherein the processor is adapted to:

c) continuously measure the distance between the vehicle and another vehicle moving forward to the vehicle using the 3-D image obtained from jointly processing the pixels of the images taken by the cameras of the first monitoring system;

d) continuously measure the distance between the vehicle and a vehicle moving behind the vehicle using the 3-D image obtained from jointly processing the pixels of the images taken by the cameras of the second monitoring system;

e) upon detecting that the braking lights of the another vehicle were turned on, automatically transmit an alert signal to the vehicle behind that the another vehicle is braking.

The processor may be further adapted to: a) for any speed of the vehicle, calculate a minimal threshold safety distance required for allowing the vehicle to stop in case the another vehicle abruptly stops;

b) continuously update the threshold according to the speed of the vehicle and optionally to the relative speed between the vehicles; c) Upon detecting that the distance is below the threshold, automatically transmit an alert signal to the driver of the vehicle with an indication that the current distance is shorter than the safe braking distance of the vehicle at the current speed.

The processor may further be adapted to activate an automatic braking system, which will reduce the speed to be below the threshold, upon detecting that after a predetermined time the driver of the vehicle does not reduce speed.

The vehicular apparatus may comprise:

a) a first monitoring system installed on the vehicle and directed aside to the vehicle;

b) a second monitoring system installed on the vehicle and directed to the opposing side,

wherein the processor is adapted to:

c) continuously measure the distance between the vehicle and an obstacle being another vehicle moving aside the vehicle or an object being aside the vehicle, using the 3-D image obtained from jointly processing the pixels of the images taken by the cameras of the first monitoring system;

d) continuously measure the distance between the vehicle and the obstacle using the 3-D image obtained from jointly processing the pixels of the images taken by the cameras of the second monitoring system; e) upon detecting that the distance is below a predetermined value, automatically issue an alert signal to the driver of the vehicle.

The processor may be adapted to control an autonomous driving system.

The cameras may be directed to at least one tire of the vehicle, where the processor is adapted to inspect its intactness by processing the images taken by the cameras whenever the vehicle stops or during movement while the tire rotates.

The cameras may also be directed to the back seat of the vehicle, where the processor is adapted to detect if a person has been forgotten in the vehicle by processing the images taken by the cameras.

The cameras may be directed forward, where the processor is adapted to detect incident light having intensity above a predetermined threshold and to automatically issue a dimming signal to a dimmer or an optical filter being a part of the front or rear window.

The cameras and the processor may be implemented by a smartphone.

The proposed vehicular apparatus may be implemented on a helmet of a bike or motorcycle rider.

The present invention is also directed to an accident avoiding system for use in conjunction with first, second and third vehicles traveling in a same lane wherein said first vehicle is positioned forwardly of said vehicle and said second vehicle is positioned forwardly of said third vehicle, comprising detection apparatus mounted in said second vehicle for automatically detecting a braking operation initiated by said first vehicle and for generating a signal which is indicative of detection of said initiated braking operation; and alert generating apparatus responsive to said generated signal for generating an alert receivable by said third vehicle or by a driver thereof as a warning that said first vehicle initiated a braking operation.

In one embodiment, the detection apparatus comprises a forward optical sensor configured to detect illumination of braking lights of the first vehicle, a frame grabber unit for digitizing images captured by said forward optical sensor, and a controller which is operable to process data digitized by said frame grabber unit according to stored instructions.

In one embodiment, the detection apparatus further comprises a signal receiver and a controller in data communication with said receiver, and the system further comprises a signal generator mounted in the first vehicle that is connected to, or in data communication with, a switch engageable by a brake pedal following application of a braking force; a short-range transmitter in communication with said signal generator; and a directional antenna in communication with said transmitter, wherein a brake application signal is rearwardly transmittable to said receiver mounted in the second vehicle upon actuation of said switch and said controller is operable to generate the braking operation detection signal in response to receiving the brake application signal.

In one embodiment, the alert generating apparatus comprises one or more braking lights that are mounted on, and visible through, a rear window of the second vehicle, said one or more rear window braking lights are configured to be iUuminated independently of tail light braking lights of the second vehicle. The alert generating apparatus preferably further comprises an actuator for the one or more rear window braking lights and a controller for commanding operation of said actuator in response to generation of the braking operation detection signal.

In one embodiment, the alert generating apparatus comprises a receiver and a control unit in data communication with said receiver which are mounted in the third vehicle; and a signal generator, transmitter and directional antenna mounted in the second vehicle, for generation and transmission of a wireless alert signal to said receiver mounted in the third vehicle in response to generation of the braking operation detection signal.

Any one of the embodiments of the detection apparatus may be used in conjunction with any one of the embodiments of the alert generating apparatus.

In one aspect, the control unit mounted in the third vehicle is operable to generate a driver-receptive sensory alert to indicate to the driver that a braking force must be urgently applied. The driver-receptive sensory alert may be a visual alert or an audible alert.

In one aspect, the system further comprises a digital projector in communication with the control unit mounted in the third vehicle, said projector configured to cause a predetermined message that is stored in a memory device of the control unit mounted in the third vehicle to be displayed. The projector may be configured to project an image of the predetermined message onto a dashboard or onto a vehicle-mounted media screen, inject the predetermined message into a user interface of the media screen so that the predetermined message will be displayed on the media screen, or be integrated with an on-board computer of the third vehicle so that a corresponding icon will be displayed on the dashboard.

In one aspect, the controller mounted in the second vehicle is operable to generate a driver-receptive sensory alert to indicate to the driver of the second vehicle that a braking force must be urgently applied.

In one aspect, the controller mounted in the second vehicle is also operable to transmit the brake application signal to the third vehicle after being received from the first vehicle. In one aspect, one or more of the first, second and third vehicles are autonomous vehicles.

The present invention is also directed to an accident avoiding method in conjunction with first, second and third vehicles traveling in a same lane wherein said first vehicle is positioned forwardly of said vehicle and said second vehicle is positioned forwardly of said third vehicle, comprising the steps performed by said second vehicle of automatically detecting a braking operation initiated by said first vehicle; generating a signal which is indicative of detection of said initiated braking operation; and transmitting, to said third vehicle, an alert which is responsive to said generated signal as a warning that said first vehicle initiated a braking operation.

Brief Description of the Drawings

In the drawings:

- Fig. 1 schematically illustrates a prior art monitoring system, used by the apparatus of the present invention;

- Fig. 2 schematically illustrates the implementation of an apparatus for detecting dangerous scenarios of impending collisions between vehicles, according to an embodiment of the invention;

- Fig. 3 schematically illustrates the implementation of an apparatus for detecting dangerous scenarios of impending collisions between vehicles, according to another embodiment of the invention;

Fig. 4 schematically illustrates the implementation of an apparatus for detecting dangerous scenarios of impending collisions between vehicles, according to another embodiment of the invention;

- Fig. 5 schematically illustrates an accident avoiding system according to another embodiment of the invention;

- Fig. 6 schematically illustrates an accident avoiding system according to another embodiment of the invention; - Fig. 7 schematically illustrates an accident avoiding system according to another embodiment of the invention; and

- Fig. 8 is a flow chart of a method implementing the use of a brake application signal.

Detailed Description of Preferred EmtwMtimmitJi

The present invention is related to an accident avoiding system and method. Dangerous scenarios of impending collisions between vehicles or between a vehicle and an object, due to violations in maintaining a minimum headway, or due to unawareness, are automatically detected.

The apparatus described in the embodiments of Figs. 1-4 consists of one or more monitoring systems, each of which comprising horizontally or vertically deployed 2-D cameras with an overlapping part of their field of view. Each monitoring system is installed on a vehicle and is capable of providing effective three- dimensional (3-D) data, based on image analysis of the overlapping field of view, which is aimed to a desired direction. This data is analyzed by each system in real time and provides an accurate estimation of the distance, size, movement direction and speed of any object within the overlapping field of view. Such a system is described for example, in USP 8,111,289.

Fig. 1 (prior art) schematically illustrates a monitoring system 10, used by the apparatus of Figs. 1-4. System 10 comprises at least one photographic device, such as Charged Coupled Device (CCD) camera 12 and/or thermal camera 11 (i.e., Infra-Red camera), motors 13 and a computerized system 15.

The computerized system 15 is responsible for performing the processing required for the operation of this invention as described hereinabove. The computerized system 15 receives, at its inputs, data from active cameras that are attached to system 10 (e.g., CCD camera 11, thermal camera 12, CMOS based camera, etc.). The data from the cameras is captured and digitized at the computerized system 15 by a frame grabber unit 16. As aforementioned, the computerized system 15 processes the received data from the cameras in order to detect, in real-time, objects at the monitored area, which may impose a potential risk of collision. The processing is controlled by controller 141 according to a set of instructions and data regarding the background space, which is stored within the memory 151. The computerized system 15 outputs data regarding the detection of suspected dangerous objects and/or to notify other systems (such as an alert system or an automatic braking system by communication signals 191 that are generated from communication unit 19.

The cameras can be configured in a variety of ways and positions. For example, a pair of identical cameras may be located vertically one above the other on the same pole or horizontally, with an appropriate spacing, for obtaining overlapping field of view.

The cameras or imagers may be un-identical and may have different central axis of symmetry or of optical magnification, provided that they have at least an overlapping part of their field of view. In this case, a calibration process will be performed, to compensate for the difference of symmetry or of optical magnification.

Of course, when using at least two CCD cameras each of which is located at same view angles but at a distance from each other and/or at least two Infra-Red cameras each of which is located at the same view angles but also at a distance from each other, additional details on a suspected dangerous objects can be acquired. For example, the additional details can be the distance of the object from the cameras, the relative spatial location of the object at a monitored area, the size of the object etc. Using a single camera Oike prior art does) results in two-dimensional (2-D) images, which provide less details, but when using, in combination, 2-D images from two or more cameras, depth parameters are obtained (i.e., "effective three-dimensional"). Preferably, when using at least two cameras of the same type, both turn aside and/or are elevated together, although the angle of perspective is different. Furthermore, the fact that the objects are obtained from at least two cameras, enables it to elongate the detection range, as well as to reduce the false alarm rate.

In the pixel processing stage, each pixel in each image from the sequence of images is mathematically processed from each camera that provide images at same time period. The mathematical process is based on Gaussian curve that is generated from a continuous measurement of pixels from previous images, wherein the location of each pixel of the current image is compared with a threshold value that is dynamically calculated along the operation of system 10. The threshold value dynamically corresponds to the danger degrees. The pixel processing process detects either moving objects or static objects. After the mathematical process is done, and one or more suspected dangerous objects are detected (i.e., pixels that their location on the Gaussian curve exceed the current threshold), effective three-dimensional (3-D) data on the suspected object is calculated by system 10. The effective 3-D data represents further parameters regarding the suspected object. The effective 3-D data is generated from at least two cameras, by using the triangulation method (e.g., the distance of the suspected object is calculated from the parameters of the distance between the two cameras and the angle of each camera from which the 2 D photo has been taken). The effective 3-D data is used for detecting pixels that may represent objects which are potentially under collision risk.

In the logic processing stage, the detected pixels that may represent a dangerous object (i.e., the objects) are measured by using different parameters, in order to decide whether they are dangerous or not. The measured parameters are compared to a predetermined table of values that corresponds to the measured parameters, which can be:

1. The dimension of the suspected object, its length and its width 2. The track of the suspected object in relation to the monitored area.

3. Movement parameters, such as direction that was created from one

or more pixels, velocity etc.

System 10 (Fig. l) is used to measure and provide the location (i.e., the location of the object in a three-dimensional coordinates system) of a detected object, such as the range and azimuth of the object. The location is relative to a reference coordinate system on earth. The location of the object in the three-dimensional coordinate system is obtained due to an arrangement of at least two imagers. Preferably, the imagers are digital photographic devices such as CCD or CMOS based cameras or Forward Looking Infra-Red (FLIR) cameras.

Preferably, at least a pair of identical CCD cameras, such as camera 12 of Fig. 1 and/or pair of FLIR cameras, such as camera 11 of Fig. 1 are positioned in such a way that system 10 sees each object, as it is captured by the charged coupled device of each camera, in two distinct projections. Each projection represents an image that comprises a segment of pixels wherein the center of gravity of a specific object in the image has specific coordinates, which differ from its coordinates in the other projection. The two centers of gravity of the same object have the pixel coordinate system for the first camera and the pixel coordinate system for the second camera.

The image processing means is used to filter noise-originated signals and extract possible targets in the images and determine their azimuth and range according to their location in the images and the location disparity (parallax) in the two images coming from the two cameras (e.g., two units of CCD camera 12).

Using two FLIR cameras positioned on the system vertical (or horizontal) axis and two additional video cameras (e.g., CCD cameras), operating in the normal vision band, located horizontally from the two sides of the system vertical axis, the different camera types are optimal on different conditions: the FLIRS are optimal at night and in bad weather and the video cameras are optimal in the daytime and in good weather.

Fig. 2 schematically illustrates the implementation of an apparatus for detecting dangerous scenarios of impending collisions between vehicles, according to an embodiment of the invention. The apparatus 20 comprises two monitoring systems 10a and 10b, which are installed on a vehicle 21a moving along a lane 22a of a road 23 with two lanes 22a and 22b. Each lane is defined by a shoulder 24 and a separator line 25 for separating between adjacent lanes. System 10a, which is installed on vehicle 21a, is directed forwardly and includes two cameras 26a and 27a with a field of view ai and 012, respectively. Both cameras 26a and 27a are spaced such that their overlapping field of view is the sector ao. System 10b, which is also installed on vehicle 21a, is directed rearward and includes two cameras 26b and 27b with a field of view βι and β2, respectively. Both cameras 26b and 27b are spaced such that their overlapping field of view is the sector βο.

In this scenario, vehicle 21a moves between vehicle 21b and 21c, such that vehicle 21b is covered by sector ceo of system 10a and vehicle 21c is covered by sector βο of system 10b. System 10a continuously measures the distance dl between vehicle 21a and 21b using the 3-D image obtained from jointly processing the pixels of the images taken by cameras 26a and 27a. Similarly, system 10b continuously measures the distance d2 between vehicle 21a and 21c using the 3-D image obtained from jointly processing the pixels of the images taken by cameras 26a and 27a.

Upon detecting that the braking lights of vehicle 21b were turned on (i.e., the driver of vehicle 21b started braking), apparatus 20 automatically transmits an alert signal to vehicle 21c with an indication that vehicle 21b is braking. The signal is received by a receiver in vehicle 20, which provides a visual or voice alert to the driver of vehicle 21c. This allows the driver of vehicle 21c to start braking or at least to reduce speed, even though the driver of vehicle 21c cannot see the braking lights of vehicle 21b. This reduces the risk of a chain collision between vehicles 21a-21c.

For any speed of vehicle 21a, apparatus 20 calculates a minimal threshold safety distance that is required for allowing vehicle 21a to stop in case vehicle 21b abruptly stops. This threshold is continuously updated according to the speed of vehicle 21a and optionally the relative speed between vehicles 21a and 21b. Upon detecting that the distance dl is below the threshold, apparatus 20 automatically transmits an alert signal to the driver of vehicle 21a with an indication that the current distance dl is shorter than the safe braking distance of vehicle 21a at the current speed and that he should reduce speed to avoid collision. If for example, after a predetermined time (typically less than few seconds) the driver of vehicle 21a does not reduce speed due to unawareness, apparatus 20 may be adapted to activate an automatic braking system, which will reduce the speed to be below the threshold. Similar apparatus 20 may be installed also on vehicle 21b or 21c, in order to communicate with other neighboring vehicles.

Fig. 3 schematically illustrates the implementation of an apparatus for detecting dangerous scenarios of impending collisions between vehicles, according to another embodiment of the invention. In this case, vehicle 21a is moving along a lane 22a of a road 23 with two lanes 22a and 22b. System 10a, which is installed on vehicle 21a, is directed leftward and cameras 26a and 27a are spaced such that their overlapping field of view is the sector AO. System 10b, which is also installed on vehicle 21a, is directed rightward and includes two cameras 26b and 27b that are spaced such that their overlapping field of view is the sector δο.

In this scenario, vehicle 21b moves along lane 22b, left to vehicle 21a, such that vehicle 21b is covered by sector λθ of system 10a. System 10a continuously measures the distance d3 between vehicles 21a and 21b using the 3-D image obtained from jointly processing the pixels of the images taken by cameras 26a and 27a.

Similarly, system 10b continuously measures the distance d2 between vehicle 21a and 21c using the 3-D image obtained from jointly processing the pixels of the images taken by cameras 26a and 27a.

Upon detecting that the distance d3 is below the threshold (for example, due to drift in the movement direction of vehicle 21b, apparatus 20 automatically transmits an alert signal to the driver of vehicle 21a with an indication that the current distance d3 becomes shorter than the threshold, and therefore, there is a risk of collision. If for example, after a predetermined time (typically less than few seconds) the driver of vehicle 21b does not perform corrective steering due to unawareness, apparatus 20 may be adapted to activate an automatic braking system, which will reduce the speed and allow vehicle 21b to bypass vehicle 21 and avoid collision.

In a different scenario, a pedestrian 30 is walking near the right shoulder 24 and getting close to road 23. Upon detecting that the distance d4 between vehicle 21a and pedestrian 30 is below the threshold (indicating that the pedestrian 30 may cross the road) and calculating that the vector of movement of pedestrian 30 may lead to an impending intersection with the vector of movement of vehicle 21a, apparatus 20 automatically transmits an alert signal to the driver of vehicle 21a with an indication that the current distance d4 becomes shorter than the threshold, and therefore, there is a risk of running over pedestrian 30. Similarly, the movement direction of vehicle 21a may drift rightward (due to unawareness of the driver) and there is a risk of getting off the road 23. In this case, upon detecting that the distance d5 between vehicle 21a and shoulder 24 is below the threshold, apparatus 20 automatically transmits an alert signal to the driver of vehicle 21a with an indication that the current distance d4 becomes shorter than the threshold, and therefore, there is a risk of getting off the road 23 or of a collision with an object of the road (e.g., a tree or a light pole). The same applies when there are other obstacles with a potential collision risk, such as bike rider moving on the shoulder 24, a vehicle that stopped on shoulder 24 etc.

According to another embodiment, apparatus 20 may be used to implement autonomous driving, such as automatic parking and stopping the vehicle in response to identification of a red traffic light or a "stop" sign unawareness of the driver.

Since the apparatus 20 provides an accurate estimation of the distance, size and movement direction based on 3-D data, there will be much less false alarms.

According to another embodiment, system 10a may be installed on vehicle 21a, such that the overlapping field of view of cameras 26b and 27b defined by sector δο will be directed to a tire of vehicle 21a, in order to inspect its intactness whenever vehicle 21a stops. Similar systems 10a may be installed to cover all other tires. In addition, the processor of system 10a may be adapted to analyze read time image data taken during movement (while the wheels rotate) and inspect the intactness of each tire by removing the spreading effect of imaging a rotating object.

According to another embodiment, system 10a may be installed on vehicle 21a, such that the overlapping field of view of cameras 26b and 27b defined by sector δο will be directed to the back seat of the car, in order to detect if a baby or a toddler has been forgotten in the vehicle 21a. In this case, the processor will be adapted to check the status of the engine and door opening. As long as the engine is running, there will be no alert. After detecting that the engine has been stopped, the processor will seek an indication that the driver is leaving the car, e.g., by integrating a pressure sensor into the driver's seat and detecting whether or not the driver left the seat, and optionally in combination with detecting opening and closing the driver's door. After a few seconds, if cameras 26b and 27b will detect movement of an object in sector δο apparatus 20 may be configured to activate the alarm of the siren of vehicle 21a, along with activating the vehicle's 4 blinking lights mode and optionally activate an automatic cellular transmitter to call the driver's cellphone or to send a message indicating that a person has been left in the car.

According to another embodiment, apparatus 20 may be used to protect the driver from being dazzled. In this case, during nighttime, upon detecting incident light (originating from cars that are moving toward vehicle 21a) having an intensity above a predetermined threshold (indicating possible dazzling), apparatus 20 will automatically issue a dimming signal to a dimmer or an optical filter that may be a part of the front or rear window.

According to another embodiment, apparatus 20 may be implemented using one or more smartphones, which include cameras and a relatively powerful processor. In this case, the processing will be implemented by a dedicated image processing application, to process the images received from the overlapping field of view of the cameras to get effective three-dimensional data.

According to another embodiment, apparatus 20 may be implemented on a helmet of a bike or motorcycle rider using miniature cameras and a processor that will be mounted on the helmet. The cameras may be directed forwardly and aside, to cover the field of view with potential risks for the rider (e.g., vehicles and stationary or moving obstacles). Upon detecting a scenario with potential collision risk, the apparatus may be adapted to provide audible alerts via earphones that may be inherently assembled in the helmet (for listening to music etc.).

According to another embodiment, apparatus 20 may be adapted to provide data required for autonomous driving systems for vehicles (i.e., an autonomous vehicle is a type of a driver-less car, capable of sensing its environment and navigating without human input). Autonomous driving systems are typically based on defining a destination and controlling the steering, braking and propulsion systems by the computer of the car by navigating to the destination location, using any available navigation applications, such as Waze (a GPS-based geographical navigation application program for smartphones with GPS support and display screens which provides turn-by-turn information and user-submitted travel times and route details). However, an autonomous driving system still requires sensors to sense the driving environment and to identify obstacles that must be considered during movement, such as neighboring vehicles, traffic lights, traffic signs, pedestrians and road limits. In this case, assuming that in any moving vehicle at least the driver has a cellular smartphone, cellular providers can calculate and provide continuous location data of all vehicles and pedestrians in the vicinity of vehicle 21a. Consequently, apparatus 20 can jointly process the effective 3-D data received from the cameras along with the location data received from cellular providers regarding the location of each vehicle or pedestrian in the vicinity of vehicle 21a (assuming that each pedestrian has a personal smartphone). As a result, the accuracy of the assessments made by apparatus 20 regarding impending collisions will be significantly increased.

It will be appreciated that any embodiment described herein may employ an autonomous driving system, mutatis mutandis.

Fig. 4 schematically illustrates the implementation of an apparatus for detecting dangerous scenarios of impending collisions between vehicles, according to another embodiment of the invention. In this example, apparatus 20 comprises a single-camera optical sensor 20a, which is installed on a vehicle 21a moving along a lane 22a of a road 23 with two lanes 22a and 22b. Optical sensor 20a, which is installed on vehicle 21a, is directed forwardly and includes a single camera 26a with a field of view ao. In this scenario, vehicle 21a moves between vehicle 2 lb and 2 lc, such that vehicle 2 lb is covered by sector ao of optical sensor 20a.

Upon detection by the forward optical sensor 20a of vehicle 21a that the braking lights of vehicle 21b have been illuminated (i.e., the driver of vehicle 21b started braking), apparatus 20 of vehicle 21a automatically generates a visual alert which is indicative that vehicle 21b is braking. The visual alert may be displayed by means of a LED-based braking light 28 that is mounted on, and visible through, the rear window of vehicle 21a. Rear window braking light 28 is configured to be illuminated independently of the conventional braking lights of vehicle 20a, for example tail light braking lights, and therefore will be caused to be illuminated following detection that the braking lights of vehicle 21b have been iUuminated and prior to the application of a braking force by the driver of vehicle 21a. Rear window braking light 28 may be illuminated with the same color as a conventional braking light (usually red) and will serve as a pre -braking light. Display of an illuminated rear window braking light 28 allows the driver of vehicle 21c to start braking or at least to reduce speed, even though the driver of vehicle 21c cannot see the braking lights of vehicle 21b, thereby reducing the risk of a chain collision between vehicles 2 la-2 lc.

A block diagram of accident avoiding system 30 is illustrated in Fig. 5. System 30 comprises forward optical sensor 20a, frame grabber unit 16 for digitizing the images captured by optical sensor 20a, controller 35 for processing the digitized data according to stored instructions, and actuator 37 for rear window braking light 28 which is commanded by controller 35 to be activated following determination that the processed data is indicative of a braking light illumination event.

In another embodiment, the apparatus of vehicle 21a additionally generates a wireless alert signal following detection by the forward optical sensor 20a of vehicle 21a that the braking lights of vehicle 21b have been iUuminated. The alert signal is transmitted to a receiver in rearwardly positioned vehicle 21c, and a control unit in data communication with the receiver generates in turn a visual alert in the form of an icon or a suitable pop -up message that is display able to the driver of vehicle 21c, for example on the dashboard of vehicle 21c or on an in - vehicle communication device. Transmission of the alert signal may also cause generation of an audible alert within vehicle 21c, to indicate to the driver that a braking force must be urgently applied.

With respect to accident avoiding system 40 shown in Fig. 6, a directional antenna 41 mounted on vehicle 21a and in data communication with controller 35 will ensure that the generated wireless alert signal A will be reliably transmitted to a receiver 43 mounted in the rearwardly positioned vehicle 21c, which is need of being urgently braked, but not to a receiver mounted in a laterally spaced positioned vehicle, which would unduly slow traffic flow and could even cause an accident if an unwarranted braking force were applied thereby. Wireless alert signal A may be an infrared signal. Alternatively, wireless alert signal A may be a Wi-Fi signal and receiver 43 may be associated with a dedicated vehicular Wi-Fi hotspot, and may have sufficient signal strength to facilitate transmission to one or more vehicles positioned behind vehicle 21c, so as to prevent a multiple vehicle collision, such as a chain accident.

The visual alert is displayed by means of a digital projector 39 in communication with controller 35 of rearwardly positioned vehicle 21c, in response to the reception of wireless alert signal A. Projector 39, which is mounted in a central region of vehicle 21c, or in any region thereof rearward of the dashboard, projects an image of a predetermined message that is stored in the memory of controller 35 onto the dashboard or onto a vehicle-mounted media screen. Alternatively, projector 39 is configured to inject the predetermined message into the user interface that is display able on the media screen, or is integrated with the onboard computer so that a corresponding icon will be displayed on the dashboard. According to a further embodiment, controller 35 may transmit the predetermined message using BlueTooth protocol or any other short-range communication format to the driver's smartphone, on which is installed a dedicated application that is adapted to display the message on the smartphone's screen or to convert the received alert signal A into a visible or audible indication. Since the range of Bluetooth is limited, the dedicated application may be configured to re -transmit the received signal, thereby forming a wireless communication path between following vehicles.

Fig. 7 illustrates another embodiment of the invention wherein a rearwardly positioned vehicle following a forwardly positioned vehicle is able to detect that the forwardly positioned vehicle has initiated a braking operation by means of a directional wireless signal that is transmitted from the forwardly positioned vehicle to the rearwardly positioned vehicle. Reception of this signal accompanying application of the braking force (hereinafter the "brake application signal") is indicative to the driver of the rearwardly positioned vehicle that a braking force should also be applied to the rearwardly positioned vehicle. Generation of a brake application signal is of great utility in the event that the braking lights of the forwardly positioned vehicle have malfunctioned or when the visibility is so poor, such as during the occurrence of thick fog, that the braking lights cannot be readily seen.

A brake application signal B is generated by a signal generator 52 of accident avoiding system 50 that is connected to, or in data communication such as by a wireless connection with, a switch 51, e.g. a micros witch, which is connected to the vehicle and engageable by the brake pedal following application of the braking force. Actuation of switch 51 not only causes brake lights 39 to become iUuminated, but also activates signal generator 52, whereupon short-range brake application signal B is transmitted rearwardly by means of transmitter 56 in communication with signal generator 52 and directional antenna 41 in communication with transmitter 56. A method implementing the use of a brake application signal is shown in Fig. 8. The brake application signal is generated by a forwardly positioned vehicle following detection that a braking force has been applied thereby in step 61, generally by means of the switch that is engageable by the brake pedal. The directional brake application signal is wirelessly transmitted to the receiver of a rearwardly positioned vehicle in step 63, generally positioned immediately to the rear of the vehicle that generated the brake application signal, but may be additionally transmitted to any other rearwardly positioned vehicle which is in range of the brake application signal, e.g. 30 200m. The controller of the vehicle that received the brake application signal ("the receiving vehicle") generates in step 69, in response, a driver-receptive sensory alert, which may be a visual alert or an audible alert, to indicate to the driver that a braking force must be urgently applied. The receiving vehicle automatically transmits an alert signal in step 71, even before its driver applied a braking force in step 73, to a rearwardly positioned vehicle within range as a warning that a forwardly positioned vehicle applied a braking force.

If the controller of the receiving vehicle detects in step 65 that the receiving vehicle is travelling at a speed less than a predetermined threshold, e.g. 50 kph, for example by means of an electrical connection to the speedometer or to any other speed monitoring device, the controller disables generation of the driver- receptive sensory alert in step 67. The minimum headway between adjacent vehicles that is needed when a vehicle travels at a speed less than a predetermined threshold, for example in an urban environment, allows several vehicles to be in the range of the brake application signal. The generation of a driver-receptive sensory alert is disabled to avoid causing additional traffic congestion as a result of the braking of a plurality of adjacent vehicles in response to the generation of a driver-receptive sensory alert, While some embodiments of the invention have been described by way of illustration, it will be apparent that the invention can be carried out with many modifications, variations and adaptations, and with the use of numerous equivalents or alternative solutions that are within the scope of persons skilled in the art, without exceeding the scope of the claims.