Abstract:
A system to remove debris from a vehicle camera lens using washer fluid from the vehicle&#39;s washer system is disclosed. The system analyzes a captured image and determines if the image is obstructed by debris. If the image is determined to be obstructed, the system automatically sprays the camera lens with fluid to remove the debris. The system includes a method of determining obstruction by comparing an image with a reference image. The system includes a method of determining obstruction by analyzing relative movement within a reference area of the image. The system also prevents the draining of the washer fluid due to a false obstruction reading or debris that does not come off after a few sprayings.

Description:
TECHNICAL FIELD 
     This disclosure relates to a wash system for a vehicle camera lens, and more specifically to an automated system for spraying washer fluid on the camera lens. 
     BACKGROUND 
     Rearward-facing vision systems have been used on vehicles to provide an image of an environment behind the vehicle when the vehicle is in reverse. This rear-view image may be displayed on a monitor within the vehicle cabin. The displayed image may be used to aid a driver in seeing objects behind the vehicle while backing up. Camera lenses are typically located on the exterior of the vehicle and are susceptible to becoming dirty resulting in the image being obstructed or less clear than may be desired. 
     A forward-facing vision system could provide an image of an environment in front of a vehicle. A forward-view image may be displayed on a monitor within the vehicle cabin much like the rear-view image. The displayed image could then be used to aid a driver in seeing objects in front of the vehicle while driving forward. A forward-facing camera may also be susceptible to becoming dirty resulting in the image being obstructed like that of a rearward-facing camera. 
     SUMMARY 
     In one aspect of this disclosure, an automatic spraying system for a vehicular camera is disclosed. The automatic spraying system has a camera disposed on a vehicle that captures a real-time image and sends the image to a controller. The controller receives the image and determines if the real-time image is obstructed. If the real-time image is determined to be obstructed, the controller actuates a pump to spray the camera. The pump then delivers washer fluid from a washer system to a camera lens of the camera in an attempt to remove the obstruction. 
     According to another aspect of this disclosure, a method for operating a processing unit to automatically spray a vehicle camera lens with washer fluid is disclosed. The processing unit receives a camera image. The processing unit performs digital analysis on the camera image to determine if the camera image is obstructed or compromised. The processing unit sends a signal to spray the vehicle camera lens if the camera image is determined to be obstructed or compromised. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a vehicle with a forward-facing camera located on a grill of the vehicle. 
         FIG. 2  is a diagrammatic view in which a portion of the figure is taken along line  2 - 2  of  FIG. 1 . 
         FIG. 3  is a schematic view of the interaction between the components used in an automatic camera wash system. 
         FIG. 4  is a fragmentary view of a vehicle grill with a forward-facing camera. 
         FIG. 5  is a view of an image from a forward-facing camera. 
         FIG. 6  is another view from a forward-facing camera. 
         FIG. 7  is a logic flow-chart for a processing unit to automatically wash a camera lens. 
         FIG. 8  is another logic flow-chart for a processing unit to automatically wash a camera lens. 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
       FIG. 1  shows a vehicle  10  with a camera  12  located on a grill  14  of the vehicle  10 . In this example, the camera  12  points forward and is capable of capturing an image  18  (see  FIGS. 5 and 6 ) of an environment in front of the vehicle  10 . The image  18  may be displayed on a video screen  20  within the vehicle cabin (see  FIG. 3 ) and aid a driver in seeing objects located in the path of the vehicle. The image  18  generated by the camera  12  may be a real-time image or a still image. 
     A forward-view image displayed within a vehicle cabin may be advantageous for vehicles with a high hood-line or other geometry that may block the driver&#39;s view of the environment directly in front of the vehicle. Such a forward-view may be particularly advantageous for vehicles that are used for recreational off-roading. Having a displayed image of the environment immediately in front of the vehicle that would otherwise be blocked from the driver&#39;s view could aid in choosing the most advantageous wheel path when traversing undulating terrain. Forward-view cameras may also be used for obstacle detection and lane detections systems. As well, cameras may be deployed around the exterior of a vehicle and used in conjunction with vision systems for autonomous vehicles. 
       FIG. 2  shows the camera  12  mounted to the grill  14  of vehicle  10 . The camera may be mounted to any other appropriate structure of the vehicle, such as a front fascia, bumper, hood or roof. The camera  12  has a field of vision  22  bounded by a camera view angle upper limit  24  and a camera view angle lower limit  26 . The camera  12  is capable of capturing an image  18  within the camera field of vision  22 . In the depicted embodiment, the camera  12  is orientated such that an exterior vehicle component  30  is captured in the field of vision  22 . The exterior vehicle component  30  leading edge  32  establishes a ground view proximal limit  34  that ends at a proximal point  36 . If the camera is orientated such that an exterior vehicle component  30  is not captured in the field of vision  22 , then the camera view angle lower limit  26  will coincide with the ground view proximal limit  34  and end at the proximal point  36 . The camera  12  may also be orientated and focused such that a camera view angle center line  38  is directed to a distal point  40  a fixed horizontal distance  42  from the proximal point  36 . 
     The exterior vehicle component  30  is shown as a front fascia component  46  adjacent to and/or covering a portion of a front bumper  48 . The camera  12  may also be placed on the vehicle  10  in varying orientations and directions in which the ground view proximal limit  34  may be provided by other exterior vehicle components  30 , or portions of exterior vehicle components, such as bumpers, spoilers, fenders, doors, hoods, trunks, hatches or tailgates. Multiple exterior vehicle components  30  may be captured in the field of vision  22  and provide a varying ground view proximal limit  34  across the field of vision  22 . The ground view proximal limit  34  may also be provided by a combination of the camera view angle lower limit  26  and ground view proximal limit  34  across the field of vision  22 . 
       FIG. 3  shows a camera  12  having a camera lens  52  disposed proximate an outlet  54  of a spray nozzle  56 . The spray nozzle  56  is fluidly connected to a pump  58  via a first fluid delivery tube  60 . The pump  58  is in turn in fluid communication with a windshield washer system  62  via a second fluid delivery tube  64 . The pump  58  may be connected directly to the spray nozzle  56  eliminating the need for the first fluid delivery tube  60 . The pump  58  may also be the same pump as used in the windshield washer system  62 , or disposed inside of a reservoir in the windshield washer system  62 , eliminating the need for the second fluid delivery tube  64 . Alternatively, the pump  58  may be connected to a separate and exclusive fluid reservoir (not shown) instead of being incorporated into the vehicle&#39;s windshield washer system  62 . 
     The windshield washer system  62  holds washer fluid  66  and the pump  58  is actuated to draw the fluid  66  from the windshield washer system  62  and deliver it to the spray nozzle  56 . The spray nozzle  56  in turn is configured to direct the fluid  66  onto the camera lens  52  of the camera  12 . The pump  58  and spray nozzle  56  may be configured in combination to deliver a spray of suitable force and coverage to clean the camera lens  52 . 
     The pump  58  may be activated by a driver using a camera wash button, switch, or similar control (not shown) located in the vehicle cabin. The pump  58  may also be activated by a controller  68 , or processing unit, operatively associated with the camera  12  and the pump  58 . The controller may send an image request signal  72  to the camera  12  and receive an image signal  74   a  back from the camera  12 . The system may also be configured for the camera  12  to transmit a constant image signal  74   a  feed to the controller  68  without need of the image request signal  72 . The controller  68  performs a digital analysis on the camera image to determine if the image is obstructed. If the image is determined to be obstructed, the controller  68  sends a pump activation signal  76  to activate the pump and spray the camera lens  52 . 
     The camera  12  may simultaneously send an image signal  74   b  to the video screen display  20  located in the vehicle or the controller  68  may send an image signal  74   c  to the video screen display  20 . The image request signal  72  and image signals  74   a ,  74   b ,  74   c  may be sent and received wirelessly using a transceiver, or sent and received through a hard wire connection between the components. The camera  12  may also be designed to broadcast an image signal  74  that may be received by any device tuned into the broadcasted signal. 
     The automatic spraying system may use fluid  66  from the windshield washer system  62  thus taking away fluid  66  from being used to wash the windshield or other intended purpose. To minimize this concern, the controller may be in communication with the windshield washer system  62  and receive a fluid level signal  78 . The controller  68  may be programmed to send a pump activation signal  76  only when the remaining quantity of fluid  66  is above a set level within the windshield washer system  62 . As well, the controller  68  and/or pump  58  may be configured to provide an activation of the spray nozzle  56  that is of a controlled duration, such as one second. 
     To prevent the system from draining a washer fluid supply unnecessarily if an obstruction on the lens cannot be cleared by the spray system, the controller  68  may be configured to deliver a limited/maximum number n of sprays in a single activation sequence then cease spraying. This may be achieved, for example, by configuring the controller  68  to increment a spray count by a count of one when sending the pump activation signal  76 . The controller then may accrue the spray counts and only send a pump activation signal  76  if the spray count is less than n+1. If n is set as 2, for example, the automatic spraying system will spray the camera lens  52  only two times during a sequence then stop to avoid wasting more fluid. 
       FIG. 4  shows the spray nozzle  56  disposed on the grill  14  below the camera  12 . The outlet  54  of the spray nozzle  56  is directed upwards to spray the camera lens  52 . In a forward-view image embodiment of a vehicle with a partially blocking hood-line, the area of the environment most useful to the driver is provided by the camera between the ground view proximal limit  34  and the camera view angle center line  38  (see  FIG. 2 ). The spray nozzle outlet  54  may be pointed at this lower area of the camera lens  52  to focus the spray more in this area and provide a more efficient system. Alternatively, the spray nozzle  56  may be located above and/or to the side of the camera lens  52  from the top or sides, the location chosen to provide better cleaning efficiency for its intended application. 
       FIG. 5  is an example of an image  18  of an environment in front of the vehicle  10  in which an obstruction  82  blocks a portion of the image  18 . The obstruction  82  may be caused by dirt or debris on the camera lens  52  and may block a portion of the view such as that of a right side wheel path  84   a . The controller  68  may use a reference image of an exterior vehicle component  30  and compare the image  18  to the reference image for inconsistencies. The exterior vehicle component  30  in the illustration provides a reference line  86  across the image  18 . The controller  68  performs an analysis of the image  18  and recognizes a compromise of the reference line  86 . The term compromise, as used herein, is intended to encompass any interruption, obscuration, or other interference with the image. If the reference line  86  is determined to be compromised, the controller  68  may send a pump activation signal  76  to spray the camera lens  52  and remove the debris causing the blocked view. 
     In the illustration, the reference line  86  is provided by a substantially straight leading edge  32  of a front fascia component  46  that spans the entire width of the image  18 . However, any combination and shapes of exterior components  46 , or portions of exterior components  46 , which are within the field-of-view of the camera  12 , may be used. The exterior components  46  are a fixed constant within the field-of-view of the camera  12  and may be used to establish a constant profile in every analyzed image  18 . Compromised profiles may give an indication of an obstruction  82  on the camera lens  52 . The camera  12  may be positioned on the vehicle  10  to provide an exterior view of the vehicle and to capture exterior vehicle components  30  to establish fixed profiles for analysis of the image  18 . The controller  68  may in turn perform an analysis of the image  18  and activate the pump if portions of the image  18  are compromised in comparison with the fixed constants of the reference image. 
       FIG. 6  is an example of a real-time image  18  of an environment in front of the vehicle  10  in which an obstruction  82  blocks a portion of the real-time image  18 . In this example, the obstruction  82  blocks the view of a portion of the left wheel path  84   b . The controller  68  may perform an analysis of the relative motion of the real-time image  18 . Since exterior vehicle components  30 , distant objects and the sky display little or no relative movement in the real-time image  18 , the controller may perform an analysis on a reference area  88  of the real-time image  18 . The real-time image  18  may be divided up into a grid of pixels as represented by dashed lines  90 . The dashed lines  90  are shown as equal spaced squares but the curvature of the camera lens  52  may provide for curved pixels of differing sizes around the real-time image  18 . The reference area of the real-time image  18  to be analyzed may be bound in a vertical direction by an upper boundary  92  and a lower boundary  94  to provide a reference area expected to exhibit the greatest relative movement. The upper boundary  92  may also be set at the camera view angle center line  38  (see  FIG. 2 ). The lower boundary  94  may also be defined by an exterior vehicle component  30 . 
     When the vehicle  10  is moving, pixels  90  in the reference area  88  will show relative motion from one adjacent pixel to the next (downward for forward vehicle motion, as represented by arrow  98 ). However, the pixels  90  in the reference area  88  in which the obstruction  82  appears will not show relative motion from one adjacent pixel to the next (represented by ‘X’  96 ). The controller  68  may activate the pump  58  to spray the camera lens  52  if a certain percentage of the reference area  88  does not exhibit relative motion. The threshold percentage of the reference area  88  to initiate the spray may be optimized for the vehicle and may be set at or around 10%. The controller  68  may communicate with a vehicle bus (not shown) to obtain a vehicle speed to increase accuracy of the relative motion analysis. If the vehicle is not moving, or moving at a very slow rate, the relative motion from one adjacent pixel to the next will be reduced, which could lead to a false indication of an obstruction and thus the pump activation signal may not be warranted. 
       FIG. 7  is a method for operating a processing unit to automatically spray a vehicle camera lens with a fluid. The camera is activated at step  102  to start the logic sequence. The camera may be activated by a driver activating a control within the vehicle cabin. Camera activation resets a spray count to zero as shown at step  104 . An event indicating a start of a drive cycle (such as ignition key-on) may also be used to reset the spray count to zero. At step  106  the image from the camera is compared to a reference image to determine whether an obstruction is present. At step  108 , if the image comparison indicates no obstruction, then the image is deemed clear of obstruction and the processing unit may return to step  106 . In one embodiment, step  110  may be used to reset the spray count to zero when the camera image is determined to not be obstructed. 
     At step  108 , if the image is determined to be compromised, then the image may be obstructed and the processor moves to step  112 . Step  112  checks the spray count, and if the spray count is already at two, then the processing unit sends a signal to indicate that the camera lens is obstructed, as indicated at step  114 . Step  112  prevents the processing unit from continuing to spray a camera lens that has a false obstructed reading or debris that cannot be removed by a spray of fluid. At step  112 , if the spray count is less than three, then the logic sequence moves on to step  116 . At step  116 , the processing unit sends a signal to the pump to spray the camera lens, as indicated at step  116 . At step  118  the processing unit increments a spray count and then returns to step  106  to continue the analysis. 
       FIG. 8  is another method for operating a processing unit to automatically spray a vehicle camera lens with a fluid. The camera is activated at step  122  to start the logic sequence. Step  124  resets the spray count to zero. Step  126  holds the logic sequence until the vehicle begins to move. If there is an obstruction of the image noticed while the vehicle has yet to begin moving, the driver may manually activate the system to spray the camera lens. Once the vehicle begins to move the logic sequence moves to step  128  and the processing unit analyzes the reference area for relative movement. At step  130 , if relative movement is detected in the reference area greater than a threshold percentage of the reference area, then the camera lens  52  is deemed to be clear. At step  132 , the spray count is reset to zero and the logic sequence returned to step  126  to continue the analysis. 
     At step  130 , if no motion is detected within a portion of the reference area greater than a threshold percentage, then the real-time image is deemed to be obstructed. The threshold value may be optimized for each system and use. An effective threshold value may be as high as 90%. At step  134  the spray count is reviewed. If the spray count is 2, then the logic sequence moves to step  136  and a message is displayed to the driver to indicate that the camera lens is obstructed. From block  136 , the method loops back to block  126  and the spray nozzle will not be activated further until the counter is reset by an action such as manually cleaning the lens. If the spray count is not 2, then the logic sequence moves on to step  138  in which the processing unit sends a signal to the pump to spray the camera lens. At step  140  the spray count is incremented by one and the logic sequence is returned to step  126  to continue the analysis. 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.