Abstract:
Various examples of an apparatus for mounting a camera on a vehicle are disclosed. An apparatus comprises a first portion of a first material with a first end configured for attaching to a camera and a second end configured for mounting to a vehicle. The apparatus is configured to maintain the camera in a substantially calibrated position. A second portion of a second material is coupled to the first portion, wherein the second material is capable of deforming upon an impact to the apparatus and returning the apparatus to the calibrated position upon exposure to an energy source. In another example, the apparatus is constructed entirely of the second material.

Description:
BACKGROUND 
       [0001]    The present invention relates to examples of an apparatus and method for restoring a camera mounting to a calibrated position. Cameras are prevalent on commercial vehicles for providing back-up viewing, surround vehicle viewing and object detection. Cameras are generally mounted external to the vehicle to provide optimal views. To provide a precise view as required for proper system operation, the cameras are placed on a fixed bracket external to the vehicle. In one example, the bracket is adjusted to a calibrated position. In another example the position of the bracket is fixed, the camera learns the fixed position and the camera is calibrated to that position. During driving situations, the camera and its fixed bracket may be exposed to impact, which may move the camera out of its original calibrated position. If the camera is out of the calibrated position, the view provided to the object detection system and/or to the driver is out of alignment. Particular areas around the vehicle may no longer be under surveillance of a camera when it is out of the calibrated position and system performance may suffer. Therefore, there is a need for a way to restore the camera mounting to its calibration position. 
       SUMMARY 
       [0002]    Various examples of an apparatus for mounting a camera on a vehicle are disclosed. An apparatus comprises a first portion of a first material with a first end configured for attaching to a camera and a second end configured for mounting to a vehicle. The apparatus is configured to maintain the camera in a calibrated position. A second portion of a second material is coupled to the first portion, wherein the second material is capable of deforming upon an impact to the apparatus and returning the apparatus to the calibrated position upon exposure to an energy source. 
         [0003]    Various examples of an assembly for a camera mounting are disclosed. The assembly comprises a camera and a bracket comprising a first portion with an end for fastening to the camera. The bracket includes a second portion coupled to the first portion with a shape memory material in a first form. The second portion is capable of deforming upon an impact to the apparatus and reforming to the first form upon exposure to an energy source. 
         [0004]    An example of a method of configuring a camera assembly for a vehicle is disclosed. The method comprises fastening a camera on a first end of a bracket and fastening a second end of the bracket to a vehicle. The bracket comprises a portion between the first end and the second end with a shape memory material in a predetermined form. The method includes calibrating the camera assembly, determining the camera assembly is no longer in the calibrated position and exposing the shape memory material to an energy source such that the shape memory material returns to the predetermined form. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    In the accompanying drawings which are incorporated in and constitute a part of the specification, embodiments of the invention are illustrated, which, together with a general description of the invention given above, and the detailed description given below, serve to exemplify the embodiments of this invention. 
           [0006]      FIG. 1  illustrates a schematic representation of commercial vehicle equipped with cameras on the tractor and trailer according to an example of this invention. 
           [0007]      FIG. 2  illustrates a camera assembly with a bracket according to an example of the present invention. 
           [0008]      FIG. 3  illustrates a camera assembly according to another example of the present invention. 
           [0009]      FIG. 4  illustrates a camera assembly according to another example of the present invention. 
           [0010]      FIG. 5  illustrates a method of restoring a camera bracket to a calibrated position. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    With reference to  FIG. 1 , a commercial vehicle  10  is shown. The commercial vehicle  10  includes a tractor  11  and a trailer  12 . The tractor  11  includes a camera assembly  14   a.  The trailer  12  includes a first camera assembly  14   b  and a second camera assembly  14   c.  There may be more or fewer camera assemblies on each portion of the commercial vehicle  10 . 
         [0012]    Each camera assembly  14   a,    14   b,    14   c  is placed relatively high on the structure of the commercial vehicle  10  in order to obtain a view around the commercial vehicle  10 . As will be explained, each of the camera assemblies  14   a,    14   b,    14   c  are calibrated when installed to maintain a view of the area around the commercial vehicle  10 . The camera assemblies  14   a,    14   b,    14   c  may be part of an imaging system, such as used for vehicle back up alarms, object detection or surround view. 
         [0013]    The camera assemblies  14   a,    14   b,    14   c  extend beyond the profile of the tractor  11  and trailer  12 . As such, the camera assemblies  14   a,    14   b,    14   c  are more likely to be exposed to impact with objects, such as tree limbs, signs and garage entryways, while the commercial vehicle  10  is in service. Impact to a camera assembly is detrimental because, for example, a surround view system relies on a precise geometric relationship among the views provided by each camera assembly around the vehicle. If the relationship among the camera views is changed due to an impact to one of the camera assemblies, there will be artifacts in the surround view image and the imaging system&#39;s ability to interpret objects in the image will be deleteriously affected. 
         [0014]    Each of the camera assemblies  14   a,    14   b,    14   c  includes a camera. The cameras  14   a,    14   b,    14   c  may be of the same type, for example the Blue Eagle digital camera from Silicon Micro Sensor GmbH. Each of the camera assemblies  14   a,    14   b,    14   c  includes a bracket to affix the camera to the tractor  11  or trailer  12 , as will be described. 
         [0015]    With reference to  FIG. 2 , assembly  14   b  as affixed to the trailer  12  includes a camera  20   b.  The camera  20   b  is shown affixed to a bracket  30  on a side of trailer  12 . The bracket  30  maintains the camera  20   b  in a substantially stable position during normal operation of the commercial vehicle  10 . The imaging system with camera  20   b  is generally calibrated after the camera  20   b  is installed on the vehicle and no adjustments would be made to the bracket  30 . 
         [0016]    The bracket  30  includes a first portion  22  with a first end  24  configured for receiving the camera  20   b.  The camera  20   b  can be fastened to the first end  24  by mechanical fasteners, adhesives or other means. The first portion  22  includes a second end  25  configured for affixing to the trailer  12 . The second end  25  of the bracket  30  may optionally be attached to a base portion  28 , which is then affixed to the trailer  12 . The first portion  22  may be a rigid material, such as steel, aluminum or industrial plastic. 
         [0017]    The bracket  30  includes a second portion  26 , which separates the first end  24  and the second end  25  of the first portion  22 . In one example, the second portion  26  is in at the approximate midpoint between the first end  24  and the second end  25 . In another example, the second portion  26  is a different shape than the first portion  22 . The structure of the second portion  26  is such that it is isotropically weakened or selectively directionally weakened. Any impact to the camera assembly  14   b  will cause deflection or deformation at the weaker second portion  26  prior to causing any deformation to the first portion  22 . In the example in  FIG. 2 , the shape of the second portion  26  is a folded or spring shape. The shape of the first portion  22  may be an S-shaped curve. The shape of the second portion  26  may be that of a three dimensional space-filling curve, where there is not a single direction of the second portion  26  that is stronger than any other direction. 
         [0018]    The second portion  26  comprises a material different than the first portion  22 . The material of the second portion  26  can be a shape memory alloy, such as Nitinol or similar material. The shape memory alloy is first set in a custom predetermined form, such as the shape shown in  FIG. 2 . Shape setting is accomplished by constraining the shape memory material in the desired position and applying an energy source, such as heat or electricity. Because of the expense of the shape memory material, the section of the bracket  30  of the second portion  26  may be shorter than the section of the bracket  30  comprising the first portion  22 . In one example, the second portion  26  is less than 10% of the overall length of the bracket  30 . 
         [0019]    Shape memory alloys exhibit characteristics wherein a shape is set into the material at a low temperature and the shape memory alloy will return to the set shape upon exposure to a high temperature. The shape memory alloy section is made weaker than the material of the first portion  22  of bracket  30  by virtue of its form and dimensions. Upon impact to any point on the camera assembly  14   b,  the view of camera  20   b  may be shifted and no longer be in its calibrated position. The shape memory alloy portion  26  has a yield strength less than the first portion  22  so that the second portion  26  preferentially deforms before the first portion  22 . For example, the yield force of the second portion  26  may be between about 10 pounds and 20 pounds force. Deformation to the second portion  26  can be corrected using the method described herein, since a shape memory alloy returns to its original shape when exposed to an energy source, such as heat. However, since a heat source may be above 100C, for example, it is advantageous if the camera  20   b  is protected by a heat shield element (not shown). The camera  20   b  is then returned to its original calibrated position. Therefore, the entire bracket  30  would not have to be replaced after impact nor would the imaging system and camera  20   b  require an extensive recalibration to ensure the camera  20   b  is in the correct position. 
         [0020]    In another example, the first portion  22  located closest to the second portion  26  and the second portion  26  would be coated, with epoxy paint for example. If the bracket  30  were subject to deformation, the paint would craze, crack or flake. The crazing, cracking or flaking gives the driver a visual means to determine that the bracket  30  has been moved out of its calibrated position. 
         [0021]    In another example, the second portion  26  of the bracket  30  may be a standardized shape. The second portion  26  of the bracket  30  would be replaceable so that if the shape memory material could not return to its original predetermined form, the second portion  26  could be substituted with a new bracket portion. 
         [0022]      FIG. 3  illustrates another example of a camera assembly  14   b.  In this example, the first portion  22 ′ and the second portion  26 ′ of the bracket  30 ′ are a single piece made of the same material. The material may be shape memory material, such as Nitinol. In this example, the first portion  22 ′ and the second portion  26 ′ are in a predetermined shape of two S-curves in non-coincident planes. In case of impact to the camera assembly  30 ′, the entire bracket  30 ′ will be deformed and the entire bracket  30 ′ would need to be subject to the energy source to be reformed to the predetermined shape. 
         [0023]    The bracket  30 ′ of  FIG. 3  also includes an indicator means. The bracket  30 ′ includes an indicator feature  40   a  on the first portion  22 ′ and an indicator feature  40   b  aligned with the indicator feature  40   a  on another section of the first portion  22 . The indicator feature  40   a  can be an arrow that would be in alignment with the indicator feature  40   b  arrow when the bracket  30 ′ is in the calibrated position. 
         [0024]    As shown in  FIG. 3 , the indicator feature  40   a  is not in alignment with indicator feature  40   b.  In this example, a driver or a technician for the commercial vehicle  10  could see that the bracket  30 ′ has likely sustained an impact, causing the indicators features  40   a,    40   b  to be out of alignment. The technician could then use the method described herein to reform the bracket  30 ′ to its calibrated position. 
         [0025]    In another example, the bracket  30 ′ would be within the view of another camera on the vehicle  10 , such as camera  20   c.  Camera  20   c  would determine that the camera  20   b  is out of alignment by recognizing during image processing of bracket  30 ′ that indicator feature  40   a  is out of alignment with indicator feature  40   b.  The imaging system could then provide an electronic indicator, such as a lamp, to the driver to let him know that the bracket  30 ′ out of alignment. 
         [0026]    In another example, the first portion  22 ′ and the second portion  26 ′ would be coated, with epoxy paint for example. If the bracket  30 ′ were subject to deformation, the coating would craze, crack or flake; thereby providing the driver another visual means to determine that the bracket  30 ′ has been moved out of its calibrated position. In another example, a more compliant or adhesive coating of a second contrasting color would be coated directly on the bracket  30 ′. The more craze prone coating would be added over the more compliant coating. When the top layer of craze prone coating crazes, cracks or flakes, the second color coating would be visible, making it easier to see that the bracket  30 ′ had deformed. 
         [0027]    Another method to determine that the bracket  30 ′ is no longer in the calibrated position is that the field of view of the camera  20   b  changes after impact. The imaging system can then indicate to the driver or technician that the camera  20   b  is no longer in the calibrated position. 
         [0028]      FIG. 4  illustrates another example of camera  20   b  and bracket  30 ″. In this example, the entire bracket  30 ″ is made of a shape memory material. The bracket  30 ″ is mounted to a base  28 ″. In this example, the bracket  30 ″ is shaped in a helical shape or twisted ribbon shape. In this shape, the bulk of any impact will be absorbed by the bracket  30 ″. 
         [0029]    Optionally, the camera  20   b  includes an aiming device  32 . The aiming device  32  is calibrated to view a particular point A on the base  28 ″. If the aiming device  32  no longer sees point A on base  28 ″, the imaging system can automatically determine that the camera  20   b  is no longer in the calibrated position. The aiming device  32  may be another camera. The aiming device  32  may be a light transmitting device. Point A may be a reflective device so that the aiming device  32  determines the camera  20   b  is in the calibrated position as long as the aiming device  32  is receiving a reflection. If the camera  20   b  receives an impact and the bracket  30 ″ is moved out of the calibrated position, then the light beam would no longer be reflected from Point A. 
         [0030]      FIG. 5  illustrates a flowchart for implementing a method  50  of calibrating the camera assembly, such as camera assembly  14   b.  The method  50  begins at step  52 . 
         [0031]    In step  54 , the camera assembly  14   b  receives an impact, which could be from a tree while the vehicle  10  is traveling down the road, for example. The camera assembly  14   b  may be forcibly moved out of its calibrated position by means of this external force. If the force is greater than the yield strength of the second portion  26  of the bracket  30 , the second portion  26  made of the shape memory alloy is plastically deformed. For example, the yield force of the second portion  26  may be between about 10 pounds and 20 pounds force. This yield force is less than the first portion  22  of the bracket  30 . 
         [0032]    The camera  20   b  is determined to be out of calibration in step  56 , either by the visual alignment means or the coating means as described above. If the camera  20   b  is out of calibration, the method  50  continues to step  58 . If it is determined that the camera  20   b  is not out of calibration, the method returns to step  52 . 
         [0033]    If the camera is out of calibration, the next step  58  is to heat the second portion  26  of the bracket  30 . Since the heat must be above 100C, for example, it is advantageous if the camera  20   b  is protected by a heat shield element. The heat can be applied in step  58  by direct forced air or electric means. A vehicle technician can apply the heat to the bracket  30 . 
         [0034]    In step  60 , it must be determined if the camera  20   b  is still out of calibration. The visual alignment means can be used in this instance, such that the heat applied by the vehicle technician can cease when he can view that the alignment features  40   a,    40   b  are realigned. The automatic alignment using the optical method described above may also be used. If the features are realigned, the method moves to step  62 , where the calibration is completed. 
         [0035]    If the features are not realigned, it is determined that the bracket cannot be recalibrated in step  64 . In this instance, an entirely new bracket  30  may need to be placed on the vehicle. In some instances, the impact to the bracket may have exceeded the yield strength of the first portion  22  of the bracket  30 . 
         [0036]    While the present invention has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention, in its broader aspects, is not limited to the specific details, the representative apparatus, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant&#39;s general inventive concept.