Abstract:
A method for displaying a vehicle driving space, the vehicle driving space being depicted in perspective or in three dimensions, and a driving direction to be taken by the vehicle being displayed by way of a variation of the lighting conditions in the depiction.

Description:
BACKGROUND INFORMATION  
       [0001]     Driver assistance systems are already known that assist the driver when maneuvering and when entering and leaving parking spaces. Driver assistance systems have for this purpose, in particular, ultrasonic sensors that sense distances to obstacles in the vehicle&#39;s environment. If an obstacle comes too close to the vehicle, an optical and/or acoustic warning is outputted to the driver. Also known are systems that measure a parking space and, based on the parking space measurement, assist the driver with entry into the parking space. A parking assistance system of this kind is activated by a driver, in particular, when he or she wishes to be assisted with longitudinal entry, in reverse, into a parking space between two vehicles parked along the street. During an initial longitudinal pass alongside the parking space, the length of the parking space is measured by the system using suitable spacing sensors arranged, in particular, on the side of the vehicle. The distance traveled is also continuously measured, so that the vehicle&#39;s position can be established with respect to the position of the parking space. After driving past the parking space, the driver is requested to stop and to back into the parking space. While backing up, the driver is given indications by the driver assistance system as to how he or she can optimally back into the parking space, so as to enter the parking space without collisions and with as little steering effort or maneuvering effort as possible. In order to display the steering angle to the driver, it is known, for example, to display arrows that indicate to the driver whether to steer to the left or the right. If the driver needs to stop, a stop sign, for example, is displayed to him or her.  
       SUMMARY OF THE INVENTION  
       [0002]     The method according to the present invention for displaying a vehicle driving space has, in contrast, the advantage that information as to which driving direction the driver should select is displayed to the driver in a driving space of the vehicle that is depicted in perspective or three-dimensional fashion. The driving space, in this context, is the space in front of or behind the vehicle into which the driver can move the vehicle forward or backward, depending on the selected direction of travel. The driver can thus, by way of the depiction according to the present invention of the driving space, create a relationship between the steering direction of the vehicle and the vehicle driving space. It is particularly advantageous in this context that the steering direction is displayed to the driver by way of a variation in lighting conditions, in such a way that he or she can easily and intuitively perceive the steering angle. In particular because the lighting conditions can also be continuously varied, it is possible to convey to the driver in easily understandable fashion the extent to which he or she must apply a steering angle. This on the one hand prevents overcontrolling by the driver, and on the other hand makes possible a more accurate steering position. The fact that lighting conditions are utilized for a depiction additionally avoids flooding the driver with symbols, arrows, or similar indicators presented in the image, which might overload the driver.  
         [0003]     It is particularly advantageous that the direction in which the driver is to drive is shown as brighter than a surrounding area. This highlighting makes a direction intuitively recognizable.  
         [0004]     It is further advantageous to ascertain the depiction of the vehicle driving space from the distances sensed by surrounding-area sensors. It is thereby possible to display an image that corresponds, for example, to the space in back of the vehicle, with no need to provide a camera in the vehicle.  
         [0005]     If a camera image is acquired, the driving space can easily be presented on the basis of the acquired images of the vehicle&#39;s environment. It is especially advantageous in this context to overlay the change in lighting conditions onto the image of the vehicle&#39;s environment.  
         [0006]     It is further advantageous to provide light sources on the vehicle so that the variation in lighting conditions is generated by the light sources. This allows image post-processing to be dispensed with, if the area to the rear of the vehicle is imaged with a camera. This reduces the calculation outlay for image processing. It is further advantageous to indicate a target position of the vehicle, so that the driver can orient him- or herself on the target position when parking.  
         [0007]     To warn the driver about obstacles, the obstacles can be particularly highlighted, especially by way of symbols in the display.  
         [0008]     Especially when used for motor vehicle parking assistance, the method according to the present invention offers the advantage that a driver can intuitively follow the parking instructions depicted with the use of the method according to the present invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  shows a vehicle having a driver assistance system for carrying out the method according to the present invention.  
         [0010]      FIG. 2  shows a schematically depicted parking situation.  
         [0011]      FIGS. 3 and 4  show exemplary embodiments of display depictions according to the present invention in the context of the method according to the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0012]     The method according to the present invention for displaying a vehicle driving space is used in particular in motor vehicles that participate in on-road traffic. In the depiction, the driving space located in front of the vehicle, but in particular also the driving space located behind the vehicle, can be depicted. Depiction of the space behind the vehicle is particularly advantageous, since the space behind the vehicle is generally more difficult to see, even in the case of a sedan, than the space located in front of the vehicle. Entering a parking space oriented parallel to the street, between two obstacles, generally constitutes a difficult driving maneuver. The present invention is therefore presented below with reference to a depiction of the space behind the vehicle in the context of a parking operation of this kind, i.e. entering a parking space oriented longitudinally with respect to the street.  
         [0013]      FIG. 1  schematically depicts a vehicle  1  that is equipped to carry out the method according to the present invention. Vehicle  1  has for this purpose distance sensors  3  on front end  2  of the vehicle that are preferably embodied as ultrasonic sensors. Instead of ultrasonic sensors, however, any other distance sensors, e.g. radar sensors or capacitative distance sensors, can also be used. Distance sensors  4  are likewise disposed on rear end  5  of the vehicle. In a preferred embodiment, distance sensors  7  can also be disposed on left side  6  of the vehicle in order to measure the parking space. In particular, distance sensors  9  are disposed on right side  8  of the vehicle. If applicable, different measurement technologies can also be used for the distance sensors. Preferably at least two distance sensors are disposed on sides  6 ,  8 , and at least four in each case on front end  2  and rear end  5 . The number of distance sensors can be varied. Distance sensors  3 ,  4 ,  7 ,  9  are evaluated via a data bus  10 . The signals acquired are delivered for evaluation to an evaluation unit  11  that determines, from the distance data, the distances to obstacles in the vehicle&#39;s surroundings. Evaluation unit  11  has a calculation unit  12  for this purpose. If an obstacle comes too close to the vehicle, the driver is then warned via an optical display  13  and/or via a loudspeaker  14 . Corresponding warning symbols can be presented in display  13 , while a signal sound can be outputted via loudspeaker  14 . Evaluation unit  11  can furthermore access a travel-distance sensor  15  that reports to evaluation unit  11  the distance that has been traveled. The distance traveled is ascertained, in particular, via wheel rotation speed sensors. Evaluation unit  11  furthermore accesses a steering angle sensor  16 . Steering angle sensor  16  transmits to evaluation unit  11  the vehicle steering angle that is currently being applied.  
         [0014]     As vehicle  1  drives past a parking space, laterally disposed distance sensors  9 , for example, measure the parking space. A corresponding parking space is depicted in  FIG. 2 . A parking space  23  having a sufficient length  24  has been identified between a first vehicle  21  and a second vehicle  22 . A parking space exists when a sufficient depth is determined between a curb  25  and side surfaces  26  and  27  of the first and second vehicles, respectively. The parking space has a sufficient length if the parking space exhibits the requisite depth at least over a length that is necessary for parking the vehicle. A safe distance  28  from the first vehicle and a safe distance  29  from second vehicle  22  are taken into account in determining the parking space length.  FIG. 2  shows a depiction of a space behind a vehicle as provided in display  13 . For better orientation, a bumper  30  of vehicle  1  is also overlaid onto the image. In a first embodiment, the depiction shown in  FIG. 2  can be calculated from the data acquired with the distance sensors. In another embodiment, the image depicted can also be acquired by a camera  17  that is mounted, in particular, on the rear end of vehicle  1 . Camera  17  observes the space behind the vehicle. It is embodied, in particular, as a wide-angle camera. The image data sensed by camera  17  are delivered to evaluation unit  11 . The acquired image data are preferably processed by calculation unit  12 , in particular distortion-corrected, in the case of an extreme wide-angle image. The processed image data are presented on display  13 . In a further embodiment, the acquired image data can also be first delivered in unprocessed form to display  13 . Also evident in the driving space in  FIG. 2  is an obstacle  31 , for example a planter. The driver must not drive the vehicle against this obstacle  31  during the parking operation.  
         [0015]     Once the parking space has been measured and the driver has driven the vehicle past the parking space, he or she is requested, by way of display  13  and/or loudspeaker  14 , to stop the vehicle and then back into parking space  23 . The target parking area is shown highlighted in  FIG. 2 . In order to reach the parking space, firstly a route is calculated that the vehicle must follow in order to reach the parking space.  
         [0016]      FIG. 3  shows a perspective depiction of the driving space. Display  13  is embodied, in particular, as a display in the center console of the vehicle. It serves, for example, as the output of a navigation system. In a further embodiment, display  13  can also be integrated into a combination instrument in the vehicle. It is moreover also possible to provide a three-dimensional display in the form of a so-called head-up display, with which a virtual image is projected onto a vehicle window, in particular onto the windshield.  
         [0017]     In  FIG. 3 , this route that the vehicle is to follow is depicted on display  13  as trajectory  40  having a left boundary  41  and a right boundary  42 . Also depicted is a deflection point  43  at which the driver must change the steering angle. By way of the display that is operated according to the present invention, the driver is given instructions for steering the vehicle into the parking space. For that purpose, a region  45  between left boundary  41 , right boundary  42 , bumper  30 , and line  43  identifying the deflection point is highlighted. The boundary lines themselves need not be depicted, but such depiction may be possible in a further embodiment. In the exemplary embodiment presented here, region  45  is depicted as being brighter. In particular, the region toward left boundary  41  is depicted as being brighter. This brighter depiction oriented toward left boundary  41  informs the driver that he or she must turn the steering wheel to the left. The reason for this is that the current setting of the steering angle, sensed via steering angle sensor  16 , indicates application of a steering angle that is directed too far to the right to allow trajectory  40  to be followed. To ensure that a correction can be correspondingly made, according to the present invention an indication is thus given to the driver to move the steering wheel to the left.  
         [0018]     If the driver performs the necessary steering correction, the highlighted region expands to deflection point  43 . The driver now knows that he or she can drive as far as the deflection point with no need to perform any further steering correction. He or she also recognizes this from the fact that the light distribution is now uniform in the entire driving space ahead of bumper  30 . If the driver had turned the steering wheel too far to the left, area  45 ′ depicted in  FIG. 4  would become smaller again, and a center point of the brightness would shift, starting from bumper  30 , to the right toward right boundary  42 . It is thus possible for a driver to effect a precise adjustment of the steering in order to reach the target (parking space  23 ).  
         [0019]     Obstacle  31  is highlighted by a special warning symbol  44 , so that a driver can pay particular attention to it in the presentation. In particular, however, the obstacle would also be particularly emphasized, e.g. colored red, if the highlighted path of the vehicle behind bumper  30  would intersect the position of the obstacle. A driver is thus made particularly aware of an obstacle positioned in such a fashion if it is located in his or her path. Instead of a brighter depiction, colored illumination can also be simulated in order to direct the driver&#39;s attention to the direction of travel that needs to be followed.  
         [0020]     In a first embodiment, the depiction shown in  FIGS. 3 and 4  is calculated by calculation unit  12  on the basis of the sensor data of distance sensors  3 ,  4 ,  7 ,  9 , and outputted on display  13 . In a further embodiment, it is also possible only to calculate region  45 ,  45 ′, and to superimpose it on an acquired camera image so that region  45 ,  45 ′ is depicted more brightly, according to the present invention, on display  13 .  
         [0021]     In a further embodiment, light sources  18 ,  19  that can be changeably controlled by evaluation unit  11  can also be disposed on the vehicle. In a first embodiment, these are light sources in visible light, so that a space behind the vehicle illuminated by the light sources is imaged by camera  17 . The light impression according to  FIGS. 3, 4  is generated in the image by corresponding activation of light sources  18 ,  19  by evaluation unit  11 . The light sources can be integrated into the ordinary vehicle lights. They can also, however, be arranged on the vehicle as additional light sources.  
         [0022]     In a further embodiment, light sources  18 ,  19  can also be infrared light sources, camera  17  in this case likewise being embodied as an infrared camera that is sensitive in the infrared region of the camera. The light sources then illuminate the area behind the vehicle with infrared light in such a way that regions  45 ,  45 ′ appear correspondingly on display  13 . Illumination in the infrared region avoids any disturbance of other vehicles.  
         [0023]     Light sources  18 ,  19  are equipped with a brightness controller, so they can be controlled to different brightness levels. They are directed toward the region behind bumper  30 . If, for example, light source  19  arranged on right side  8  of the vehicle is operated at a higher level than light source  18  arranged on left side  6  of the vehicle, the impression depicted in  FIG. 3  is produced. A directional orientation of the light sources in accordance with a trajectory that is to be followed can additionally be achieved by way of a pivotable optical system or pivotable baffles.