Abstract:
A driver assistance system and method are disclosed which provide improved determination of possible collision objects. The system includes at least one sensor and a classification device. The threshold value of the classification device for classifying an object sensed by the at least one sensor as a possible collision object is lowered when a possible hazard situation in a region of surrounding located in front of the motor vehicle is determined based on data received from an inter-vehicular communication device. As a result, hazard situations which may not yet be determined by means of sensors belonging to conventional vehicles because of the distance or the position of the possible hazard situation with respect to the motor vehicle can be detected earlier.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to German Patent Application No. 202013006196.0 filed Jul. 9, 2013, which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The application relates to a driver assistance system for a motor vehicle, a motor vehicle, a computer program product and a computer-readable medium. 
     BACKGROUND 
     DE 10 2010 006 214 A1 discloses an emergency braking assistance for the automatic braking of a vehicle for avoiding a collision or reducing collision consequences when a detected collision object is known, wherein at a determined intervention time a braking system of the vehicle is automatically activated in such a manner that a collision with a detected collision object can be avoided or at least the collision consequences reduced. The intervention time is determined as a function of the end time of a determined driver reaction time and of the determined last possible braking time. 
     SUMMARY 
     The present disclosure provides a driver assistance system for a motor vehicle, a motor vehicle, a computer program product and a computer-readable medium, which makes possible a further improved determination of possible collision objects. 
     According to an aspect of the present disclosure, a driver assistance system for a motor vehicle includes at least one sensor designed for sensing objects in the region of surroundings of the motor vehicle. The driver assistance system also includes a classification device, designed for classifying objects sensed by the at least one sensor as possible collision objects. Furthermore, the driver assistance system includes a computer unit and a computer program product which, when it is executed on the computer unit, instructs the computer unit to carry out the following steps: (i) determining if there is a possible hazard situation in a region of surroundings located in front of the motor vehicle, based on data received from a vehicle-to-vehicle communication device and/or a vehicle-to-vehicle infrastructure communication device of the motor vehicle; and (ii) in the case that it is determined that there is a possible hazard situation in the region of the surroundings located in front of the motor vehicle, lowering of a threshold value of the classification device for classifying an object sensed by means of the at least one sensor as a possible collision object. 
     The driver assistance system according to the present disclosure makes possible further improved determination of possible collision objects. This is affected, in particular, by determining if there is a possible hazard situation in a region of surroundings located in front of the motor vehicle based on data received from a vehicle-to-vehicle communication device and/or a vehicle-to-infrastructure communication device of the motor vehicle. The threshold value of the classification device for classifying an object sensed by means of the at least one sensor as possible collision object is lowered when the mentioned data a possible hazard situation in the region of the surroundings located in front of the motor vehicle is determined. This is based on the consideration that hazard situations can also be determined based on this data in an advantageous manner which cannot yet be determined by means of sensors belonging to conventional vehicles because of the distance or the position of the possible hazard situation with respect to the motor vehicle. Because of this, such possible hazard situations can be detected early on. Furthermore, lowering the threshold value advantageously makes possible reliably classifying smaller possible collision objects as collision objects in such situations for example a motorcycle or objects which are smaller than a motorcycle. 
     In one aspect, the present disclosure provides at least one sensor designed as a runtime-based sensor for sending and receiving signals. In the mentioned embodiment, the threshold value of the classification device is a value of signal strength of a signal sent back from an object. Such runtime-based sensors are particularly suitable for sensing possible collision objects in the region of surroundings of the motor vehicle. The sensor in this case can be selected in particular from the group consisting of a radar sensor, a lidar sensor and an ultrasound sensor. The mentioned sensors, which are also called surround sensors, are increasingly provided in motor vehicles, as a result of which the number of components needed for the driver assistance system can be advantageously reduced. 
     In a further aspect of the present disclosure, the at least one sensor is designed as an optical camera, and in particular as a front camera of the motor vehicle. The threshold value of the classification device is a size of an object contained in an image recorded by means of the optical camera. By means of an optical camera, possible collision objects in the region of the surroundings of the motor vehicle can also be reliably determined 
     In another aspect of the present disclosure, the driver assistance system additionally includes an actuating device designed for automatically actuating at least one element of the motor vehicle, selected from the group consisting of a braking device, a driving device, a steering device and a warning device. Thus, in a possible hazard situation, autonomous intervention in the driving dynamics of the motor vehicle can be advantageously affected by means of the driver assistance system or the occupants of the motor vehicle, in particular the driver of the motor vehicle informed of such a hazard situation. 
     In a further aspect of the present disclosure, the computer unit is additionally instructed to carry out the following steps: lowering a triggering threshold of the actuating device for automatic actuating the at least one element of the motor vehicle in the case that it is determined that there is a possible hazard situation in the region of the surroundings located in front of the motor vehicle. By lowering the triggering threshold for automatically actuating the at least one element, for example a time to collision value or TTC-value, the latency period or reaction time of the driver assistance system can be advantageously further reduced and the automatic actuation compared with a previous triggering threshold takes place at an earlier time. In a possible hazard situation, earlier outputting of a warning message or an earlier autonomous intervention in the driving dynamics of the motor vehicle can thus take place. 
     The driver assistance system can be selected from the group consisting of an emergency braking system, a lane-keeping assistant and a collision warning system. Such driver assistance systems are particularly suited for avoiding a collision with the determined possible collision object by means of autonomous intervention in the driving dynamics and/or by means of outputting a corresponding warning message. 
     Another embodiment of the present disclosure relates to a motor vehicle, which includes a driver assistance system according to any one of the mentioned aspects. The motor vehicle can in particular be a passenger car or a utility vehicle. 
     A further embodiment of the present disclosure relates to a computer program product executable on a computer unit of a driver assistance system of a motor vehicle. The driver assistance system includes at least one sensor and one classification device. The sensor is designed for sensing objects in the region of surroundings of the motor vehicle. The classification device is designed for classifying objects sensed by means of the at least one sensor as possible collision objects, The computer program product instructs the computer unit to carry out the following steps: (i) determining if there is a possible hazard situation in a region of surroundings located in front of the motor vehicle, based on data received from a vehicle-to-vehicle communication device and/or a vehicle-to-infrastructure communication device of the motor vehicle; and (ii) in the case that it is determined that there is a possible hazard situation in the region of the surroundings located in front of the motor vehicle, lowering a threshold value of the classification device for classifying an object sensed by means of the at least one sensor as possible collision object. In addition to this, a further embodiment of the present disclosure relates to a computer-readable medium, on which a computer program product is stored. 
     The motor vehicle and the computer program product and the computer-readable medium according to the mentioned embodiments have the advantages already mentioned in connection with the relevant driver assistance system described above. 
     A further aspect of the present disclosure relates to a method for operating a driver assistance system of a motor vehicle, wherein the driver assistance system includes at least one sensor and on classification device. The at least one sensor device is designed for sensing objects in the region of surroundings of the motor vehicle. The classification device is designed for classifying objects sensed by means of the at least one sensor as possible collision objects. The method includes the following steps: (i) determining if there is a possible hazard situation in a region of surroundings located in front of the motor vehicle based on data received from a vehicle-to-vehicle communication device and/or a vehicle-to-infrastructure communication device of the motor vehicle; (ii) in the case that it is determined that there is a possible hazard situation in the region of the surroundings located in front of the motor vehicle, lowering of a threshold value of the classification device for classifying an object sensed by means of the at least one sensor as possible collision object. The method according to the mentioned embodiment has the advantages already mentioned in connection with the relevant driver assistance system. 
     A further aspect of the present disclosure relates to a device for operating a driver assistance system of a motor vehicle. The driver assistance system includes at least one sensor and one classification device. The at least one sensor is designed for sensing objects in the region of surroundings of the motor vehicle. The classification device is designed for classifying objects sensed by means of the at least one sensor as possible collision objects. The device for operating the driver assistance system includes: (i) means for determining if there is a possible hazard situation in a region of surroundings located in front of the motor vehicle, based on data received from a vehicle-to-vehicle communication device and/or a vehicle-to-infrastructure communication device of the motor vehicle; and (ii) means for lowering a threshold value of the classification device for classifying and object sensed by means of the at least one sensor as possible collision object in the case that it is determined that there is a possible hazard situation in the region of the surroundings located in front of the motor vehicle. By means of the mentioned device for operating a driver assistance system of a motor vehicle further improved determining of possible collision objects is made possible as already mentioned. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements. 
         FIG. 1  shows a flow diagram of a method which is carried out by means of a computer unit; 
         FIG. 2  shows an example of a traffic situation, in which a method, which is carried out by means of a computer unit, can be employed; and 
         FIG. 3  shows a driver assistance system according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application and uses of the present disclosure. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description. 
       FIG. 1  shows a flow diagram of a method which is carried out by means of a computer unit of a driver assistance system according to one or more aspect of the present disclosure mentioned above when a computer program product is executed on the computer unit. 
     Here, the driver assistance system includes at least one sensor and one classification device. The sensor is designed for sensing object in the region of surroundings of the motor vehicle and the classification device of classifying objects sensed by means of the at least one sensor as possible collision objects. The sensor in this case can be designed as a runtime-based sensor for sending and receiving signals, such as a radar sensor, a lidar sensor and/or an ultrasound sensor. Alternately, the sensor can be designed as an optical camera. 
     The driver assistance system additionally includes an actuating device, which is designed for automatically actuating at least one element of the motor vehicle, selected from the group consisting of a braking device, a driving device, a steering device and a warning device. For example, the driver assistance system may be designed as an emergency braking system, which is also called collision imminent braking or CIB, as lane-keeping assistant and/or as collision warning system. 
     During an operation of the motor vehicle, a message is received in a step  30  by means of a vehicle-to-vehicle communication device and/or by means of a vehicle-to-infrastructure communication device of the motor vehicle. The mentioned communication devices in this case are also called car-to-car (C2C) or vehicle-to-vehicle (V2V) communication or car-to-infrastructure (C2I) or vehicle-to-roadside (V2R) communication and summarized, as car-to-x (C2X) or vehicle-to-x (V2X) communication. These communication devices may be generically referred to as an inter-vehicular communication device. 
     Based on the message received in the step  30 , it is determined in a step  40  if there is a possible hazard situation in a region of surroundings located in front of the motor vehicle. A possible hazard situation in a region of the surroundings located in front of the motor vehicle can be inferred for example in the case that another vehicle located in traveling direction in front of the motor vehicle carries out emergency braking and transmits information regarding a hazard situation connected with this to further road users by means of a vehicle-to-vehicle communication device. 
     In the case that it is determined in the step  40  that there is a possible hazard situation in the region of the surroundings located in front of the motor vehicle, automatic lowering of a threshold value of the classification device for classifying an object sensed by means of the at least one sensor as a possible collision object takes place in a step  50 . In the case that the at least one sensor in this case is designed as a runtime-based sensor for sending and receiving signals, the threshold value of the classification device is a value of a signal strength, for example a value of an amplitude or an intensity of a signal returned from an object, which is, for example, determined in decibel or dB. Lowering the threshold value in this case is a lowering of the value of the signal strength above which an object sensed by means of the at least one sensor is classified as a possible collision object. 
     If the at least one sensor is designed as an optical camera, the threshold value of the classification device is a size of an object contained in an image recorded by means of the optical camera. The lowering of the threshold value in this case is a lowering of the size of an object contained in a recorded image, above which said object is classified as a possible collision object. 
     Determining data by means of the at least one sensor for sensing objects in the region of the surroundings of the motor vehicle takes place in a step  60 . Based on the data determined in the step  60  it is determined in a step  70  if at least one object is sensed by the at least one sensor. If no object is sensed by the sensor, the steps  60  and  70  are carried out repeatedly. In the case, by contrast, that at least one object is sensed by the at least one sensor, classifying of the objects sensed by means of the at least one sensor as possible collision objects, i.e. objects which are determined to be above the threshold value of the classification device, and according to other objects, which do not constitute possible collision objects, i.e. objects which do not exceed the threshold value of the classification device. 
     In a step  90  it is determined if at least one of the objects sensed by the sensor and classified in the step  80  forms a possible collision object. In the case that it is determined in the step  90  that none of the objects sensed by the sensor forms a possible collision object, the steps  60  and  70  as well as  80  and  90  if appropriate are carried out repeatedly. In the case, by contrast, that it is determined in the step  90  that at least one of the objects sensed by the sensor forms a possible collision object, it is determined in a step  100  based on the data determined by the at least one sensor if a triggering threshold for automatic actuating of the at least one element is exceeded. For example, it is determined if a TTC-value, i.e. the time to a possible collision with the object undershoots a predetermined threshold value. 
     If it is determined in the step  100  that the triggering threshold for automatically actuating the at least one element of the motor vehicle is not exceeded, the steps  60  and  70  and if appropriate  80 ,  90  and  100  are carried out repeatedly. In the case, by contrast, that it is determined it the step  100  that the triggering threshold is exceeded, automatic actuation of the at least one element takes place in a step  110 . 
     Raising the threshold value of the classification device lowered in the step  50  to the original value takes place in a configuration of the method following a predetermined period of time. A position of the motor vehicle can also be determined and the threshold value of the classification device raised to the original value in the case that the message received in the step  30  is provided with position data regarding the possible hazard situation, after the motor vehicle has passed the position of the possible hazard situation or in the case that the motor vehicle is subsequently located outside a predetermined region about the position of the hazard situation. 
     In the case that it is determined in the step  40  that there is no hazard situation in the region of the surroundings located in front of the motor vehicle, the threshold value of the classification device for classifying objects sensed by means of the at least one sensor as possible collision objects is maintained, i.e. the method after the step  40  is directly continued with the further steps  60  and  70  and if appropriate  80 ,  90 ,  100  and  110 . 
     By means of the shown embodiment it is thus made possible for example, when a hazard situation which is not directly obvious is timely known through communication via a vehicle-to-vehicle communication, to specifically lower the sensitivity in particular of an emergency braking assistance system of the motor vehicle at this point in order to ensure safe triggering and to prepare the overall system for the situation. Thus the latency period of the system and thus also the reaction time can be reduced. It can thereby be avoided that the system erroneously fails to trigger. This is advantageous in particular with smaller hazard objects in the case of which the sensor-based detection as a possible obstacle is more complex. By lowering the detection threshold, i.e. the threshold value of the classification device, at this special point or in this situation, triggering can be made possible in a reliable manner. 
     A hazard situation can for example be an invisible congestion end behind a curve, as is explained in more detail in connection with the following figure. In this regard,  FIG. 2  shows an example of a traffic situation, in which a method, which is carried out by means of a computer unit, in particular the method explained in connection with  FIG. 1 , can be employed. In the shown traffic situation, a motor vehicle  2  in the form of a passenger car travels in a traveling direction schematically indicated by means of an arrow A on a first lane  15  of a road  16 . In addition to the first lane  15 , the road  16  has a further lane  17 . The road  16  is for example part of a highway. 
     The motor vehicle  2  includes at least one sensor  3 , which is designed for sensing objects in the region of surroundings  4  of the motor vehicle  2  within a schematically represented sensing range  12 . The at least one sensor  3  in this case can be designed as a runtime-based sensor for sending and receiving signals, in particular as a radar sensor, a lidar sensor and/or an ultrasound sensor. Furthermore, the at least one sensor  3  can be designed as an optical camera. The motor vehicle  2  also includes a classification device, which is not shown in more detail in  FIG. 2 , designed for classifying objects sensed by means of the at least one sensor  3  as possible collision objects. 
     Located in traveling direction in front of the motor vehicle  2  on the first lane  15  are two further motor vehicles  13  and  14 . The motor vehicles  13  and  14  form the congestion end of traffic congestion on the first lane  15 . The congestion end in this case is located behind a curve  18  and is therefore difficult to see or imperceptible to the driver of the motor vehicle  2 . In addition, the motor vehicles  13  and  14  in the shown situation are still outside the sensing range  12  of the at least one sensor  3  of the motor vehicle  2 . 
     In the shown situation, the motor vehicle  13  has been braked to a halt by means of emergency braking, which was activated for example by the driver of the motor vehicle  13  or an emergency braking assistance system or both. The information regarding a hazard situation connected with this hazard and the exact position of said hazard situation is transmitted by means of a vehicle-to-vehicle communication device  8  of the motor vehicle  13  to the following vehicles and in particular to the motor vehicle  2 , which likewise includes such a vehicle-to-vehicle communication device  8 . Furthermore, the information regarding the hazard situation connected with this hazard and its exact position can be sent from the vehicle  13  to a roadside infrastructure device, also called roadside unit or RSU and from the latter transmitted to vehicles located in a region of the surroundings of the roadside infrastructure device. 
     As is explained in more detail in connection with the following figure, it can thereby be determined based on data received from the vehicle-to-vehicle communication device  8  of the motor vehicle  2  when there is a possible hazard situation in a region  7  of surroundings located in front of the motor vehicle  2 . In the case when it is determined as in the shown situation that there is a possible hazard situation in the region  7  of the surroundings located in front of the motor vehicle  2 , lowering of a threshold value of the classification device of the motor vehicle  2  for classifying objects sensed by means of the at least one sensor  3  of the motor vehicle  2  as possible collision objects can take place, i.e. the reaction threshold or the sensitivity of a corresponding driver assistance system of the motor vehicle  2  can be lowered. 
     Thus, triggering of the driver assistance system if required can reliably take place and the latency period or reaction time in the system reduced, by means of which in particular braking distance can be saved and an accident can be avoided depending on the situation. It can be avoided, furthermore, that the driver assistance system because of weak signal strength, for example because of only a small hazard-triggering object, such as for example a motorcycle or smaller object, fails to react. Further details are explained in more detail in connection with the following figure. 
     In this regard,  FIG. 3  shows a driver assistance system  1  of the motor vehicle  2  shown in  FIG. 2  according to an embodiment of the present disclosure. For the sake of clarity, the motor vehicle  2  is merely schematically shown in  FIG. 3 . The driver assistance system  1  is for example designed as an emergency braking system or as a collision warning system, and in addition to the at least one sensor  3  includes a classification device  5 , which is designed for classifying objects sensed by means of the at least one sensor  3  as possible collision objects. The classification device  5  to this end is connected to the at least one sensor  3  via a signal line  21 . 
     Furthermore, the driver assistance system  1  includes a computer unit  6  and a computer-readable medium  20 , wherein on the computer-readable medium  20  a computer program product is stored which, when executed on the computer unit  6  instructs the computer unit  6  to carry out the methods according to the present disclosure explained above in particular the steps of the method shown in  FIG. 1  by means of the elements mentioned there. 
     In particular, the classification device  5  in the shown embodiment is instructed for determining if there is a possible hazard situation in a region of surroundings located in front of the motor vehicle  2 , based on data received from the vehicle-to-vehicle communication device  8  and/or a vehicle-to-infrastructure communication device  9  of the motor vehicle  2 . The vehicle-to-vehicle communication device  8  and/or the vehicle-to-infrastructure communication device  9  in this case are part of a communication device  19  in the shown embodiment, which is connected to the classification device  5  via a signal line  22 . In the case that it is determined that there is a possible hazard situation in the region of the surroundings located in front of the motor vehicle  2 , the computer unit  6  is instructed furthermore for lowering a threshold value of the classification device  5  for classifying an object sensed by means of the at least one sensor  3  as possible collision object. 
     The driver assistance system  1  in the shown embodiment additionally includes an actuating device  10 , which is designed for automatically actuating at least one element  11  of the motor vehicle  2 , selected from the group consisting of a braking device, a driving device, a steering device and a warning device. The actuating device  10  to this end is connected to the at least one element  11  via a suitable control line  24 . 
     The classification device  5  in the shown embodiment is additionally designed for determining a TTC-value of an object classified as a possible collision object, i.e. the period of time to a possible collision of the motor vehicle  2  with the object, based on data determined by the at least one sensor  3 , in particular a distance and/or a speed of the possible collision object to the motor vehicle  2 . Furthermore, the classification device  5  is designed for determining when a triggering threshold of the actuating device  10  for automatically actuating the at least one element  11  is exceeded, i.e. if the determined TTC-value undershoots a predetermined threshold value. In addition, the classification device  5  is designed for automatically actuating the at least one element  11  by means of the actuating device  10  if this is the case. To this end, the classification device  5  is connected to the actuating device  10  via a signal line  23 . 
     While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment is only an example, and are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the present disclosure as set forth in the appended claims and their legal equivalents.