Abstract:
A parking assist system for a vehicle includes a camera and a display operable to display video images of an exterior scene derived from image data captured by the camera. A controller, when operating in a first or parking space locator mode, adds an overlay to the displayed video images. The overlay includes (i) a polygonal representation of the vehicle and (ii) a linear overlay extending along one side of the polygonal representation of the vehicle. The polygonal representation is offset behind and laterally from the vehicle. The controller is operable in the first mode while the vehicle is being driven by a driver of the vehicle and, with the overlay added to displayed video images, the driver maneuvers the vehicle to position the polygonal representation at a displayed target parking location. The linear overlay assists the driver in parking the vehicle at the target parking location.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of U.S. patent application Ser. No. 13/384,672, filed Jul. 27, 2010, now U.S. Pat. No. 8,874,317, which is a 371 national phase filing of PCT Application No. PCT/US2010/043330, filed Jul. 27, 2010, which claims the filing benefit of U.S. provisional application Ser. No. 61/228,655, filed Jul. 27, 2009, which are hereby incorporated herein by reference in their entireties. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a parking assist system for use in vehicles. 
       BACKGROUND OF THE INVENTION 
       [0003]    Parking assist systems are currently available only on certain luxury vehicles, and are typically relatively complex systems that are either entirely or semi-autonomous, capable of steering and/or driving the vehicle into a parking spot. Such systems typically require significant processing power in order to determine a suitable path to follow during the parking maneuver. Such systems can be relatively expensive. 
         [0004]    It would be advantageous if a parking assist system were available that required relatively less processing power, that was relatively simpler, and was relatively less expensive than some systems of the prior art. 
       SUMMARY OF THE INVENTION 
       [0005]    In a first aspect, the invention is directed to a parking assist system for a vehicle, wherein a target parking position overlay is added to a rearview scene displayed to the vehicle driver. 
         [0006]    In a particular embodiment of the first aspect, the parking assist system includes a camera mounted to the vehicle so as to receive a rearward scene, a display in the vehicle connected to the camera and configured to display an image of the rearward scene, and a controller configured to add an overlay to the image of the rearward scene. The overlay includes a representation of a target parking position. 
         [0007]    In a second aspect, the invention is directed to a parking assist system for a vehicle, that is configured to:
       select a target path for the vehicle driver to follow while parking the vehicle,   to inform the driver of the vehicle&#39;s projected path based on the vehicle&#39;s steering angle, and to inform the driver of whether the projected path matches the target path.       
 
         [0010]    In a particular embodiment of the second aspect, the parking assist system includes a camera mounted to the vehicle so as to receive a rearward scene, a display in the vehicle connected to the camera and configured to display an image of the rearward scene, and a controller configured to add an overlay to the image of the rearward scene. The overlay includes a representation of a projected path for the vehicle based on a current vehicle steering angle, and a representation of a target path for the vehicle. 
         [0011]    In a third aspect, the invention is directed to a parking assist system for a vehicle, wherein the parking assist system has two modes of operation. In a first mode a first overlay is added to a rearview scene displayed to the vehicle driver. The first overlay includes a representation of a target parking position. In a second mode a second overlay is added to the rearview scene displayed to the vehicle driver. The second overlay includes a representation of a projected path for the vehicle based on a current vehicle steering angle, and a representation of a target path segment for the vehicle. 
         [0012]    In a particular embodiment of the third aspect, the parking assist system includes a camera mounted to the vehicle so as to receive a rearward scene, a display in the vehicle connected to the camera and configured to display an image of the rearward scene, and a controller configured to operate the parking assist system in two operating modes. In a first operating mode the controller is configured to add a first overlay to the image of the rearward scene, wherein the first overlay includes a representation of a target parking position. In a second operating mode the controller is configured to add a second overlay to the image of the rearward scene, wherein the second overlay includes a representation of a projected path for the vehicle based on a current vehicle steering angle, and a representation of a target path segment for the vehicle. 
         [0013]    In a fourth aspect, the invention is directed to a parking assist system for a vehicle, wherein the parking assist system selects a plurality of target path segments for the vehicle to follow to park in a target parking spot, wherein each target path segment involves the vehicle having steering wheels pointed straight or at full lock. 
         [0014]    In a particular embodiment of the fourth aspect, the parking assist system includes a camera mounted to the vehicle so as to receive a rearward scene, a display in the vehicle connected to the camera and configured to display an image of the rearward scene, and a controller configured to select a plurality of target path segments for the vehicle to follow to park in a target parking spot. Each target path segment involves the vehicle having the steering wheels pointed straight or at full lock. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The present invention will now be described by way of example only with reference to the attached drawings, in which: 
           [0016]      FIG. 1  is a schematic illustration of a parking assist system in accordance with an embodiment of the present invention; 
           [0017]      FIG. 2  is a view of a rearward scene on a display that is part of the parking assist system shown in  FIG. 1 ; 
           [0018]      FIG. 3  is a view of a rearward scene on the display shown in  FIG. 3 , with the parking assist system in a parking spot locator mode; 
           [0019]      FIG. 4  is a view of a rearward scene on the display shown in  FIG. 3 , with the parking assist system in the parking spot locator mode, after the vehicle has traveled past a target parking spot; 
           [0020]      FIG. 5  is a view of a rearward scene on the display shown in  FIG. 3 , with the parking assist system in the parking spot locator mode, after the vehicle has backed up to a suitable position to park in the target parking spot; 
           [0021]      FIG. 6  is a view of a rearward scene on the display shown in  FIG. 3 , with the parking assist system in a parking guidance mode, showing the alignment between the projected path of the vehicle with a first target path segment for the vehicle; 
           [0022]      FIGS. 7   a - 7   d  are views of a rearward scene on the display shown in  FIG. 3 , with the parking assist system in the parking guidance mode, illustrating the progression of the vehicle along the first target path segment; 
           [0023]      FIGS. 8   a - 8   c  are views of a rearward scene on the display shown in  FIG. 3 , with the parking assist system in the parking guidance mode, showing the progression towards alignment between the projected path of the vehicle with a second target path segment for the vehicle; 
           [0024]      FIGS. 9   a  and  9   b  are views of a rearward scene on the display shown in  FIG. 3 , with the parking assist system in the parking guidance mode, illustrating the progression of the vehicle along the second target path segment; 
           [0025]      FIGS. 10   a - 10   d  are views of a rearward scene on the display shown in  FIG. 3 , with the parking assist system in the parking guidance mode, showing the progression towards alignment between the projected path of the vehicle with a third target path segment for the vehicle; 
           [0026]      FIG. 11  is a view of a rearward scene on the display shown in  FIG. 3 , with the parking assist system in the parking guidance mode, showing the vehicle having nearly completed the third target path segment for the vehicle; and 
           [0027]      FIG. 12  is a view of a rearward scene on the display shown in  FIG. 3 , with the parking system in the parking guidance mode, wherein the vehicle is parking in a perpendicular parking spot. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    Reference is made to  FIG. 1 , which shows a parking assist system  10  for use in a vehicle  11 , in accordance with an embodiment of the present invention. The parking assist system includes a camera  12 , a controller  14  and a display  16 . The camera  12  is positioned on the vehicle  11  for rearward viewing and receives a rearward scene shown at  18 . The controller  14  communicates with the camera  12  and sends an image  20  of the rearward scene  18  ( FIG. 2 ) to the display  16 , which is positioned in the vehicle cabin. The display  16  is positioned to display the image  20  of the rearward scene  18  to the vehicle driver. 
         [0029]    When the vehicle driver wants to use the parking assist system  10  ( FIG. 1 ), he or she presses a button in the interior of the vehicle  11 , which activates the parking assist system  10  in a first mode, which is a parking spot locator mode. When in the parking spot locator mode, the controller  14  adds an overlay  22  ( FIG. 3 ) to the image  20 , which assists the driver in finding a suitable parking spot for the vehicle  11  ( FIG. 1 ). The overlay  22  ( FIG. 3 ) includes a rectangle  24  which is a representation of a target parked position which is offset a selected distance behind and a selected distance laterally from the vehicle  11  ( FIG. 1 ). The size of the rectangle  24  ( FIG. 3 ) preferably represents substantially the length and further preferably represents substantially the width of the vehicle  11  ( FIG. 1 ). 
         [0030]    The overlay  22  ( FIG. 3 ) also includes a line  26  extending along the outside edge (shown at  28 ) of the rectangle  24  (i.e., the side edge of the rectangle  24  that faces outwardly from the parking spot). 
         [0031]    The line  26  extends a selected distance forward of the rectangle  24  and a selected distance rearward of the rectangle  24  and assists the driver of the vehicle  11  in lining up the vehicle  11  to be parallel to the parking lane. 
         [0032]    With the overlay  22  shown on the image  20 , the driver drives along the road until he or she finds a potential parking spot, shown at  30  in  FIG. 4 . In the exemplary embodiment shown in the figures, the driver drove forward to find the potential parking spot  30 . As shown in  FIG. 4 , the vehicle  11  has overshot the potential parking spot  30  and so the forward edge of the rectangle  24  is too far forward, overlapping with the vehicle (shown at  32 ) that is forward of the potential parking spot  30 . Having driven too far forward, the driver may put vehicle  11  ( FIG. 1 ) into reverse gear in order to back up to superimpose the rectangle  24  on the potential parking spot  30 . 
         [0033]    When the vehicle is in reverse, a representation  34  of the projected path of the vehicle is added to the included in the overlay  22  that is provided with the image  20  shown on the display  16 . The representation  34  is based on the steering angle of the vehicle and is updated as the steering angle changes. 
         [0034]    The representation  34  includes several features such as lateral edge lines  36  and distance markers  38 . The lateral edge lines  36  correspond to the lateral edges of the vehicle. The distance markers  38  each correspond to a selected distance behind the vehicle, preferably in uniform increments. 
         [0035]    As shown in  FIG. 5 , the vehicle  11  ( FIG. 1 ) has backed up sufficiently to superimpose the rectangle  24  on the potential parking spot  30 . Once in this position, the driver can see that the vehicle  11  ( FIG. 1 ) has sufficient room to fit in the parking spot  30 . It is optionally possible for the length of the rectangle  24  to be the length required by the vehicle to fit in the parking spot instead of simply representing the length of the vehicle  11  ( FIG. 1 ) itself. As will be understood by one skilled in the art, the length required by the vehicle ( FIG. 1 ) to park in a spot is some amount longer than the length of the vehicle ( FIG. 1 ) itself. 
         [0036]    Once the driver has decided that the parking spot  30  ( FIG. 5 ) is suitable, he or she may press another button on the dashboard to activate the parking assist system  10  ( FIG. 1 ) in a parking guidance mode, as shown in  FIG. 6 . 
         [0037]    In the parking guidance mode, the parking assist system  10  ( FIG. 1 ) determines a target path for the vehicle  11  to follow in order to park in the spot delineated by the rectangle  24  ( FIG. 6 ) at the time that the parking guidance mode was initiated. 
         [0038]    When in the parking guidance mode, two representations are shown on the display  16 . One is the aforementioned representation  34  of the vehicle&#39;s projected path at the current steering angle. The other is a representation shown at  40   a  of a segment of the target path to reach the parking spot delineated by the rectangle  24  ( FIG. 5 ). 
         [0039]    Initially, the driver turns the vehicle&#39;s steering wheel until the projected path representation  34  of the vehicle substantially aligns with the target path segment representation  40   a.  When they are suitably aligned, the parking assist system  10  may notify the driver that he/she can proceed to back the vehicle up along the target path. Alternatively, the alignment of the representations  34  and  40   a  visually on the display  16  may itself be considered notification to the driver that the projected path suitably matches the target path. 
         [0040]    Referring to  FIGS. 7   a ,  7   b ,  7   c  and  7   d , as the driver backs the vehicle up progressively along the target path segment, a distal portion  42  of the target path representation  40   a  change from one color to another, shortening the length of the proximal portion  44  of the representation  40   a  that remains in the first color. This gives the driver an indication of how much of the target path segment remains to be driven before another phase of the parking maneuver is to be made. 
         [0041]    Once the vehicle has driven the entire target path segment, the parking assist system  10  selects the next segment of the target path for the vehicle to follow, and represents it on the display  16  as the representation  40   b  shown in  FIG. 8   a . The second target path segment representation  40   b  guides the driver in the turn-in phase of the parking maneuver. At the point in time shown in  FIG. 8   a , the vehicle&#39;s steering wheels are still pointed straight since the first target path segment which was just completed was a straight segment. Thus, at the point in time shown in  FIG. 8   a , the driver&#39;s projected path represented at  34  is misaligned with the second target path segment represented at  40   b.    
         [0042]    As the driver turns the steering wheel to align the vehicle&#39;s projected path with the target path segment, the projected path representation  34  becomes progressively aligned with and superimposed with the target path segment representation  40   b,  as shown in  FIG. 8   b . After the driver turns the steering wheel sufficiently, the vehicle&#39;s projected path is aligned with the vehicle&#39;s target path segment, as shown by the representations  34  and  40   b  in  FIG. 8   c . The target path segment illustrated in  FIGS. 8   a ,  8   b  and  8   c  may be the path at full wheel lock (i.e., at the maximum steering angle the vehicle is capable of). 
         [0043]      FIGS. 9   a  and  9   b  show the progress of the vehicle along the second target path segment. Once the vehicle has moved along the entire second target path segment, the parking assist system  10  selects the next (i.e., third) target path segment for the vehicle to follow, which is represented in  FIG. 10   a  at  40   c . The third target path segment is the tuck-in phase of the parking maneuver and requires that the driver turn the steering wheel to the opposite limit.  FIGS. 10   a - 10   d  illustrate the driver turning the wheel to bring the projected path into alignment with the third target path segment. 
         [0044]    Once the projected path and third target path segment are aligned, the driver backs the vehicle up along the third target path segment.  FIG. 11  illustrates the vehicle having completed almost all of the third target path segment. After the third target path segment is completed, the driver has completed the entire parking maneuver. Optionally he/she can drive forward if desired to adjust the spacing between the driver&#39;s vehicle and the vehicles in front and behind. 
         [0045]    It will be noted that the parking maneuver includes three phases, a backup phase wherein the vehicle is backed up in a straight line (with the wheels pointing straight), a turn-in phase wherein the vehicle is backed up at full wheel lock in one direction, and a tuck-in phase wherein the vehicle is backed up at full wheel lock in the other direction. Providing target path segments wherein the wheels are pointed straight or are at full lock simplifies the process of aligning the projected path with the target path segment, and simplifies keeping the vehicle along the target path segment. 
         [0046]    While backing the vehicle up along a target path segment, if the driver for some reason veers off the target path by more than a selected amount, the parking assist system  10  notifies the driver, and optionally aborts the parking maneuver. 
         [0047]    Optionally, the parking assist system  10  can permit the driver to select whether the parking spot is to the left of the vehicle (as shown in the figures) or to the right of the vehicle. For a parking spot on the right of the vehicle, the turn-in and tuck-in phases would be mirror images of the turn-in and tuck-in phases illustrated in  FIGS. 8   a - 11 . 
         [0048]    It will be understood that the three target path segments need not all be the same length. 
         [0049]    It will be noted that the rectangle  24  ( FIG. 5 ) is at a fixed position behind and to the side of the vehicle. The target path for the parking maneuver is thus the same each time the vehicle is to be parked although it may be mirrored in the optional embodiment wherein the parking assist system  10  permits selecting a parking spot on the other side (i.e., the right side) of the vehicle. As a result of the consistency in the parking maneuver, the parking maneuver need not be recalculated each time the vehicle uses the parking assist system  10 . This permits the parking assist system  10  to operate using relatively inexpensive control hardware and software. 
         [0050]    In the above description, the in-cabin display  16  was used as the human/machine interface and provided the driver with instructions visually/graphically for driving the vehicle into a parking spot. It is possible to provide instructions to the driver by other means in addition to or instead of using the in-cabin display  16 . For example, the human/machine interface could include a speaker (e.g., from the vehicle&#39;s sound system) and could emit audible messages to the driver via the speaker. Such messages could be instructions in any language, such as English. For example, an instruction could be given audibly to turn the vehicle steering wheel to a selected position (e.g., full lock to the left). It will be noted that such an instruction would in effect inform the driver of the target path for the vehicle. In addition to the audible messages, or instead of them, a chime or a beep could be emitted at points in the parking process where the driver is supposed to carry out a new maneuver, to let the driver know that he/she is off course, to let the driver know that he/she is on course (i.e., that the projected vehicle path matches the target path), or for any other suitable purpose. 
         [0051]    In the above description a method and system were described for parallel parking into a parking spot. It is also possible for an embodiment of the invention to be provided for parking into a perpendicular parking spot  30  (see  FIG. 12 ). A perpendicular parking spot  30  is a parking spot that is perpendicular to the direction of travel of the vehicle when driving by. Perpendicular parking spots are typically used in parking lots for malls, office buildings and the like. In the position shown in  FIG. 12 , the vehicle has already completed some portion of the parking process and is backing into the parking spot  30 . 
         [0052]    While the above description constitutes a plurality of embodiments of the present invention, it will be appreciated that the present invention is susceptible to further modification and change without departing from the fair meaning of the accompanying claims.