Abstract:
Electric and plug-in hybrid electric vehicles include a rechargeable traction battery. An automated vehicle charging system is configured to charge the traction battery with minimal operator intervention. The vehicle charging system includes at least one tire pad including a plurality of pressure-sensitive sensors arranged at known locations of the tire pad and outputting signals having a magnitude indicative of a pressure applied by a tire at the known locations. The vehicle charging system also includes at least one controller programmed to receive the signals and control movement of a transmit coil according to a position of the tire on the tire pad that is derived from the signals. The known locations may be generally equally spaced or unevenly spaced across the tire pad. The tire pad may include a tire stop to limit motion of the tire in one direction.

Description:
TECHNICAL FIELD 
       [0001]    This application generally relates to imaging systems for locating a moving object in relation to another object, for example, using superimposed images to position a vehicle for charging. 
       BACKGROUND 
       [0002]    Electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) utilize energy stored in a traction battery to provide electric-only driving range. A vehicle charging station may be used to provide energy to the traction battery. The vehicle charging station may provide an interface that couples energy from a power source to the traction battery of the vehicle. The interface may couple the energy conductively or inductively. Conductive interfaces may include a plug that is inserted into a compatible receptacle of the vehicle. The vehicle operator must typically perform a manual operation to insert the plug into the receptacle. Inductive charging systems may include a primary charging coil that is energized with an electric current. The primary charging coil induces a current in a secondary charging coil, which may be used to charge a battery. 
       SUMMARY 
       [0003]    In at least one embodiment, a system for positioning a vehicle is provided. The system may include one or more cameras configured to provide an image stream of an area outside a footprint of the vehicle. The system may also include a controller configured to receive the image stream from the one or more cameras, augment the image stream with a vehicle receive coil symbol and a transmit coil symbol to generate an augmented image stream, and transmit the augmented image stream to a vehicle display. 
         [0004]    The augmented image stream may further include a vehicle symbol representing a position of the vehicle and the vehicle receive coil symbol may be located within the vehicle symbol. In one embodiment, the vehicle receive coil symbol represents a position of a vehicle wireless energy receive coil and the transmit coil symbol represents a position of a wireless energy transmit coil. When the vehicle receive coil symbol overlaps with the transmit coil symbol in the augmented image stream, the vehicle wireless energy receive coil may be aligned to receive wireless energy from the wireless energy transmit coil. The position of the wireless energy transmit coil may be based on a position of a target detected in the image stream. 
         [0005]    In one embodiment, a predetermined relative position between the target and the wireless energy transmit coil may be stored in memory coupled to the controller. The controller may be configured to wirelessly receive a predetermined relative position between the target and the wireless transmit coil from the wireless energy transmit coil or an enclosure thereof. The position of the wireless energy transmit coil may be based on a detection of the wireless energy transmit coil in the image stream. The position of the wireless energy transmit coil may be based on a first data set when the wireless energy transmit coil is within a field of view of the one or more cameras and a second data set when the wireless energy transmit coil is out of the field of view of the one or more cameras. The first data set may include a relative position between the vehicle and the wireless energy transmit coil based on a detection of the wireless energy transmit coil in the image stream and the second data set may include vehicle speed and direction data. 
         [0006]    In at least one embodiment, a method of positioning a vehicle is provided. The method may include generating an image stream of an area outside a footprint of the vehicle from one or more visible-light vehicle cameras. The method may further include augmenting the image stream with a vehicle receive coil symbol and a transmit coil symbol to generate an augmented image stream. The augmented image stream may be displayed on a vehicle display. 
         [0007]    The augmented image stream may further include a vehicle symbol representing a position of the vehicle and the vehicle receive coil symbol may be located within the vehicle symbol. The vehicle receive coil symbol may represent a position of a vehicle wireless energy receive coil and the transmit coil symbol may represent a position of a wireless energy transmit coil. The method may further include operating the vehicle such that the vehicle receive coil symbol overlaps with the transmit coil symbol in the augmented image stream. The method may include detecting a target in the image stream and basing the position of the wireless energy transmit coil on a position of the target. In one embodiment, the position of the wireless energy transmit coil is based on a predetermined relative position between the target and the wireless transmit coil. In another embodiment, the predetermined relative position is received by the vehicle from the wireless energy transmit coil or an enclosure thereof. The method may include detecting the wireless energy transmit coil in the image stream and basing the position of the wireless energy transmit coil on the detection. 
         [0008]    In one embodiment, the method further includes basing the position of the wireless energy transmit coil on a first data set when the wireless energy transmit coil is within a field of view of the one or more cameras and a second data set when the wireless energy transmit coil is out of the field of view of the one or more cameras or obscured by other objects within the field of view. The first data set may include a relative position between the vehicle and the wireless energy transmit coil based on a detection of the wireless energy transmit coil in the image stream and the second data set may include vehicle speed and direction data. 
         [0009]    In at least one embodiment, a system for positioning a vehicle is provided. The system may include one or more visible-light cameras configured to provide an image stream of an area outside a footprint of the vehicle and a controller. The controller may be configured to receive the image stream from the one or more cameras, augment the image stream with a vehicle receive coil positioning symbol, a transmit coil positioning symbol, and a vehicle positioning symbol to generate an augmented image stream, and transmit the augmented image stream to a vehicle display. The receive coil positioning symbol may be located within the vehicle positioning symbol. 
         [0010]    In one embodiment, when the vehicle receive coil positioning symbol overlaps with the transmit coil positioning symbol in the augmented image stream, a vehicle wireless energy receive coil is aligned to receive wireless energy from a wireless energy transmit coil at 90% or greater of maximum charging efficiency. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a diagram of a hybrid vehicle illustrating drivetrain and energy storage components, according to an embodiment; 
           [0012]      FIG. 2A  shows a schematic example of an augmented image stream provided to a vehicle display during a parking event at time 1; 
           [0013]      FIG. 2B  shows a schematic example of an augmented image stream provided to a vehicle display during a parking event at time 2; 
           [0014]      FIG. 2C  shows a schematic example of an augmented image stream provided to a vehicle display during a parking event at time 3; 
           [0015]      FIG. 2D  shows a schematic example of an augmented image stream provided to a vehicle display during a parking event at time 4; 
           [0016]      FIG. 3  is a schematic example of an augmented image stream provided to a vehicle display, including a split screen showing two different views, according to an embodiment; 
           [0017]      FIG. 4A  is an example of a shape that may be used for a target associated with a wireless energy transmit coil; 
           [0018]      FIG. 4B  is an example of a shape that may be used for a target associated with a wireless energy transmit coil; 
           [0019]      FIG. 4C  is an example of a shape that may be used for a target associated with a wireless energy transmit coil; and 
           [0020]      FIG. 4D  is an example of a shape that may be used for a target associated with a wireless energy transmit coil. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could 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. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations. 
         [0022]      FIG. 1  depicts an embodiment of a plug-in hybrid-electric vehicle (PHEV). While the vehicle described below is PHEV, the disclosed system may also be used in a purely electric vehicle or a non-plug-in hybrid-electric vehicle. Plug-in hybrid-electric vehicle  12  may comprise one or more electric machines  14  mechanically connected to a hybrid transmission  16 . The electric machines  14  may be capable of operating as a motor or a generator. In addition, the hybrid transmission  16  is mechanically connected to an engine  18 . The hybrid transmission  16  is also mechanically connected to a drive shaft  20  that is mechanically connected to the wheels  22 . The electric machines  14  can provide propulsion and deceleration capability when the engine  18  is turned on or off. The electric machines  14  also act as generators and can provide fuel economy benefits by recovering energy that would normally be lost as heat in the friction braking system. The electric machines  14  may also reduce vehicle emissions by allowing the engine  18  to operate at more efficient speeds and allowing the hybrid-electric vehicle  12  to be operated in electric mode with the engine  18  off under certain conditions. 
         [0023]    A fraction battery or battery pack  24  stores energy that can be used by the electric machines  14 . A vehicle battery pack  24  may provide a high voltage DC output. The traction battery  24  is electrically connected to one or more power electronics modules  26 . One or more contactors  42  may isolate the traction battery  24  from other components when opened and connect the traction battery  24  to other components when closed. The power electronics module  26  is also electrically connected to the electric machines  14  and provides the ability to bi-directionally transfer energy between the traction battery  24  and the electric machines  14 . For example, a traction battery  24  may provide a DC voltage while the electric machines  14  may operate using a three-phase AC current. The power electronics module  26  may convert the DC voltage to a three-phase AC current for use by the electric machines  14 . In a regenerative mode, the power electronics module  26  may convert the three-phase AC current from the electric machines  14  acting as generators to the DC voltage compatible with the traction battery  24 . The description herein is equally applicable to a pure electric vehicle. For a pure electric vehicle, the hybrid transmission  16  may be a gear box connected to an electric machine  14  and the engine  18  may not be present. 
         [0024]    In addition to providing energy for propulsion, the traction battery  24  may provide energy for other vehicle electrical systems. A typical system may include a DC/DC converter module  28  that converts the high voltage DC output of the traction battery  24  to a low voltage DC supply that is compatible with other vehicle loads. Other high-voltage loads  46 , such as compressors and electric heaters, may be connected directly to the high-voltage without the use of a DC/DC converter module  28 . The low-voltage systems may be electrically connected to an auxiliary battery  30  (e.g., 12V battery). 
         [0025]    The vehicle  12  may be an electric vehicle or a plug-in hybrid vehicle in which the traction battery  24  may be recharged by a wireless vehicle charging system  52 . The wireless vehicle charging system  52  may include an external power source  36 . The external power source  36  may be a connection to an electrical outlet. The external power source  36  may be electrically connected to electric vehicle supply equipment (EVSE)  38 . The EVSE  38  may provide a controller  54  to provide circuitry and controls to regulate and manage the transfer of energy between the power source  36  and the vehicle  12 . The external power source  36  may provide DC or AC electric power to the EVSE  38 . The EVSE  38  may be coupled to a transmit coil  40  (or primary charging coil) for wirelessly transferring energy to a receive coil  34  (or secondary coil) of the vehicle  12 . The receive coil  34  may be electrically connected to a charger or on-board power conversion module  32 . The receive coil  34  may be located on an underside of the vehicle  12 . The power conversion module  32  may condition the power supplied to the receive coil  34  to provide the proper voltage and current levels to the traction battery  24 . The power conversion module  32  may interface with the EVSE  38  to coordinate the delivery of power to the vehicle  12 . The transmit coil  40  may cause the traction battery  24  to be charged by generating an electromagnetic field about the wireless vehicle charging system  52 . When the corresponding receive coil  34  is placed in proximity to the wireless vehicle charging system  52 , it receives power by being within the generated electromagnetic field. 
         [0026]    One or more wheel brakes  44  may be provided for decelerating the vehicle  12  and preventing motion of the vehicle  12 . The wheel brakes  44  may be hydraulically actuated, electrically actuated, or some combination thereof. The wheel brakes  44  may be a part of a brake system  50 . The brake system  50  may include other components to operate the wheel brakes  44 . For simplicity, the figure depicts a single connection between the brake system  50  and one of the wheel brakes  44 . A connection between the brake system  50  and the other wheel brakes  44  is implied. The brake system  50  may include a controller to monitor and coordinate the brake system  50 . The brake system  50  may monitor the brake components and control the wheel brakes  44  for vehicle deceleration. The brake system  50  may respond to driver commands and may also operate autonomously to implement features such as stability control. The controller of the brake system  50  may implement a method of applying a requested brake force when requested by another controller or sub-function. One or more electrical loads  46  may be connected to the high-voltage bus. The electrical loads  46  may have an associated controller that operates and controls the electrical loads  46  when appropriate. Examples of electrical loads  46  may be a heating module or an air-conditioning module. 
         [0027]    The wireless vehicle charging system  52  may define an area (e.g., a parking space) for parking the vehicle  12  for charging. The area may be suitable for charging a variety of different sized vehicles. The wireless vehicle charging system  52  may provide visual feedback to a vehicle operator. The visual feedback may include one or more indicators to indicate that charging is in progress, charging is completed, or that a diagnostic condition is present that inhibits charging. The visual feedback may be part of a display that is external to the vehicle or within the vehicle. The wireless vehicle charging system  52  may communicate charging status information to the vehicle  12 . An operator display  60  in the vehicle  12  may indicate the charging status information to the vehicle operator. This may eliminate the need for external indicators that may be a part of the wireless vehicle charging system  52  and reduce the footprint of the wireless vehicle charging system  52 . 
         [0028]    The vehicle  12  may include a system controller  48 , which may be part of a controller area network (CAN bus), which may communicate with any or all of the other components of the vehicle  12 . The system controller  48  in the vehicle  12  may monitor the charging operation. The system controller  48  may compute the amount of energy being transferred and determine if more energy transfer is possible. A predetermined nominal energy transfer amount may be known and the vehicle controller  48  may compare the present energy transfer to the nominal energy transfer. The vehicle  12  may send a signal that indicates when charging is completed. The charge controller  54  may then de-energize the transmit coil  40 . 
         [0029]    The vehicle  12  may include one or more cameras  62 , which may provide images and/or video to the display  60 . The display  60  may be located in a front or center console of the vehicle  12  (e.g., in addition to or as part of the entertainment or navigation systems), in the instrument panel, in a rear-view mirror (center or sides), as a heads-up display (HUD), or any other display location. In addition, there may be a plurality of displays  60  within the vehicle, and the images or video may be displayed on any or all of them. The vehicle  12  may include one or more front cameras  64 , one or more rear cameras  66 , and/or one or more side cameras  68 . In one embodiment, the vehicle  12  may include a front camera  64 , a rear camera  66 , and two side cameras  68 . The side cameras  68  may be located on the rear view mirrors of the vehicle  12 . In this embodiment, the front and rear cameras may be centrally located or substantially centrally located, such that they are disposed on or near a longitudinal axis of the vehicle  12 . The rear camera  66  may also function as a reverse or back-up camera for assisting a driver while in reverse. In another embodiment, instead of one, middle front camera  64 , the vehicle  12  may include two front cameras  64 , with one located on or near each side of the vehicle  12 . For example, one front camera  64  may be located near each headlight of the vehicle (e.g., above or below). The cameras  62  may be exterior-facing or perimeter cameras such that they face outward from the vehicle  12  and not into or beneath/under the vehicle  12 . 
         [0030]    As a result of the one or more cameras  62 , a field of view around the vehicle  12  may be provided to the driver. The cameras  62  may provide a field of view that includes the front, rear, and/or side(s) of the vehicle. In one embodiment, a 360° or substantially 360° view of the area surrounding the vehicle  12  may be provided to the driver. The images or video from the cameras  62  may be provided to the driver via the display  60  (or to a plurality of displays  60  in the vehicle). In another embodiment, the cameras  62  may provide a view covering at least 180° of the vehicle  12 , such as at least the front or at least the rear half of the vehicle  12 . In at least one embodiment, the cameras  62  are visible-light cameras. However, it is also contemplated that the cameras  62  may sense light in other spectrums, such as infrared. 
         [0031]    With reference to  FIGS. 2A-2D , an imaging and object recognition system  100  is described. The system may be used, for example, to assist a driver in locating a transmit coil  40  and to position the receive coil  34  of the vehicle  12  over the transmit coil  40  to charge the traction battery  24  of the vehicle.  FIGS. 2A-2D  show an embodiment of a superimposed or augmented image stream  102  that may be presented on one or more displays  60  in the vehicle  12 . The term “image stream” is used herein to describe still images, a series of still images, streaming video, or any other type of visual information that may come from a camera. The source of the image stream may come from one or more of the cameras  62  installed or coupled to the vehicle  12 . The augmented image stream  102  may include the source stream with additional symbols, indicators, text, images, or other visual information not provided in the source stream added thereto. 
         [0032]    As described above, the cameras  62  may provide a 360° view around the vehicle  12 , as shown in  FIGS. 2A-2D . The source stream may include image feeds from one or more cameras  62  that have been combined to form a single stream. The image feeds from the camera(s)  62  may be received and processed by a controller, such as controller  48  or another controller within the system  100  (e.g., a dedicated entertainment/navigation controller), and delivered to the display  60 . The controller may then process the image stream and add visual information to form the augmented image stream  102 . The augmented image stream  102  is shown with the vehicle  12  traveling left to right, however, the stream may show the vehicle  12  traveling in any direction. For example, if the vehicle  12  is in “drive,” the stream  102  may show the vehicle  12  oriented vertically and traveling in an upward direction. If the vehicle  12  is in “reverse,” the stream  102  may show the vehicle  12  oriented vertically and traveling in a downward direction. Further, the field of view in the combined video stream may be manipulated and projected onto a flat surface to resemble a top-down view or projected onto a different 3-D surface to give a bird&#39;s eye or other augmented perspective to the vehicle surround. 
         [0033]    In at least one embodiment, the augmented image stream  102  may include a symbol or virtual representation  104  of the vehicle  12 . The augmented stream  102  may locate the symbol  104  in the current location of the vehicle  12  within the 360° view around the vehicle  12  provided by the cameras  62 . The symbol  104  may further include a symbol or virtual representation  106  of the receive coil  34 . The symbol  104  of the vehicle  12  may have any suitable shape. For example, the symbol  104  may be a rectangle or it may be an outline corresponding to the shape of the vehicle  12 . In one embodiment, shown in  FIGS. 2A-2D , the symbol  104  is a simplified top-view of the vehicle  12 . The symbol  106  may have any shape, which may or may not be visually similar to the actual receive coil  34 . For example, the symbol  106  may be a square or rectangle having a size that is proportional or substantially proportional to the size of the symbol  104  of the vehicle  12 . A square or rectangle may represent the casing or housing of the receive coil  34 . In one embodiment, the symbol  106  may be a circle, which may represent the shape of the receive coil  34  inside its casing or housing. The symbol  106  may be located in a location on the symbol  104  that corresponds to the location of the receive coil  34  on the vehicle  12  in a top-view. 
         [0034]    In addition to generating the augmented image stream  102 , the imaging and object recognition system  100  may also detect and recognize objects in the image streams from the cameras  62 . Parameters used to extract object data from the image stream may include one or a combination of color channel filtering, edge detection within the image leveraging processes such as image gradient calculation, and use of algorithms such as the Hough Transform for skew estimation. These are only several possible methods of extracting object data, and other methods known in the art may be used. For example, other methods or approaches may include tracking infrared light or other emitted signal(s) from the target to track it against a non-emitting background. The system  100  may detect and recognize the transmit coil  40  and/or a target  108  in the image streams from the cameras  62 . The target  108  may be a two-dimensional or three-dimensional image or object that is located with a predefined relationship to the transmit coil  40 . In one embodiment, the target  108  may be a two-dimensional image that is applied to the ground or surface near the transmit coil  40 . For example, the target may be painted, drawn, etched, carved, stamped, or otherwise applied to the ground or surface. The target may also be applied as a sticker. The target  108  may be placed, for example, behind the coil  40 , in front of the coil  40 , next to the coil  40 , or in any other known location. As used herein, “behind/in front/next to” are relative to a vehicle  12  approaching the coil  40 . The target  108  may also be a three-dimensional object, such as a sign or a free-standing object. The target  108  may be a sign that has the same shape as the two-dimensional target described above. Similar to the above, the three-dimensional target may be placed, for example, behind the coil  40 , in front of the coil  40 , next to the coil  40 , or in any other known location. 
         [0035]    The target  108  may be located in a predefined or known location relative to the transmit coil  40 . For example, a two-dimensional target  108  may be located one meter directly behind the coil  40 , measured from a center point of the target  108  and the coil  40 . Alternatively, a three-dimensional target  108  may be located one meter behind and one meter above the coil  40 , also measured from their center points. These are merely examples, however, and the target  108  and the coil  40  may have any spatial relationship. The system  100  may have the size, shape, and dimensions of the target  108  stored in memory, as well as the spatial relationship between the target  108  and the coil  40 . Accordingly, once the target  108  is detected and recognized by the system  100 , the system  100  can calculate or determine the location of the coil  40  relative to the target  108  based on the known spatial relationship therebetween. The size, shape, and dimensions of the target  108 , as well as the spatial relationship between the target  108  and the coil  40  may also be stored in memory located in the transmit coil  40  or its housing. The coil, or electronics coupled or associated therewith (e.g., within a case or enclosure surrounding the coil) may transmit information related to the size, shape, and dimensions of the target  108  and the spatial relationship between the target  108  and the coil  40  to the vehicle  12 . This may allow the vehicle  12  to have no previously stored information or knowledge of the target  108  or its spatial relationship to the transmit coil  40 . Transmission of the information may be performed over any known wireless protocol, such as wifi, Bluetooth, NFC, or others. 
         [0036]    In addition to detecting and recognizing the coil  40  and/or target  108 , the system  100  may also highlight or otherwise draw attention to the coil  40  and/or target  108 . In one embodiment, the system may highlight the coil  40  and/or target  108  by surrounding them with an indicator. The indicator may have the same or substantially the same shape as the coil  40  and/or target  108  or it may have the same shape but slightly larger. For example, in  FIG. 2A , the coil  40  has a rectangular shape and the indicator  110  surrounding it also has a rectangular shape, but slightly larger. The target  108  in  FIG. 2A  has a “T” shape and the indicator  112  surrounding it has the same shape, but slightly larger. Similar to the symbols  104  and  106 , the indicators  110  and/or  112  may be added to the image stream in the augmented image stream  102 . The indicators may have a color or pattern that makes them stand out against the background of the stream or they may blink, flash, or otherwise draw attention to themselves. The indicators  110  and  112  are not required, however, and  FIG. 2B  shows the augmented image stream  102  without the indicator  112  for the target  108 . The indicators may assist the driver in locating the coil  40  and/or target  108  and facilitate the positioning of the vehicle  12  over the coil  40 . 
         [0037]      FIGS. 2A-2D  show an example of the augmented image stream  102  that a driver of the vehicle  12  may see while attempting to park the vehicle  12  over the coil  40 . In  FIG. 2A , the stream  102  shows the vehicle symbol  104  and the receive coil symbol  106 , as well as the area surrounding the vehicle  12 . The transmit coil  40  can be seen in the images from the cameras  62  and is also highlighted by indicator  110 . In addition, the target  108  can be seen in the images from the cameras  62  and is also highlighted by the indicator  112 . As the vehicle  12  gets approaches the coil  40  and gets closer, as shown in  FIG. 2B , the transmit coil  40  is still in view of the cameras  62  and is still highlighted by indicator  110 . In the example shown in  FIG. 2B , indicator  112  is not present, however, indicators  110  and/or  112  may be included or not included during any stage of the vehicle positioning process. 
         [0038]    In  FIG. 2C , as the vehicle  12  continues to approach the transmit coil  40 , the front of the vehicle extends over and covers at least a portion of the transmit coil  40 . At a certain point during the positioning process, the vehicle  12  will cover some or all of the coil  40  such that it is out of view of the cameras  62 . At this point, the system  100  may include a symbol or virtual representation  114  of the coil  40  in the augmented stream  102 . The symbol  114  may have a shape or image similar to the actual coil  40  or it may have a different shape, for example, the shape used for indicator  110 . The symbol  114  may be shown in a different color from the symbol  104  of the vehicle  12  and/or the symbol  106  of the receive coil so that it can be differentiated by the driver. The symbol  114  may also flash or blink, similar to indicators  110  and/or  112 . In one embodiment, the symbol  104  of the vehicle may be or may turn translucent once symbol  114  is shown. This may allow the symbol  114  to stick out and be seen more easily. The symbol  114  may also be translucent. In one embodiment, the symbol  106  for the receive coil  34  may remain solid or opaque. 
         [0039]    Accordingly, as shown in  FIG. 2D , the driver may be able to steer the vehicle  12  such that the symbol  106  for the receive coil  34  lines up or overlaps with the symbol  114  for the receive coil  40 . When the symbols  106  and  114  overlap, the coils  34  and  40  are positioned such that wireless charging of the vehicle battery can occur. The symbols  106  and  114  may be sized and shaped such that any charging power can be transmitted or such that at least a certain amount of power can be transmitted. For example, to avoid inefficient charging, the symbols may be sized and shaped such that when they overlap the battery charges at least at 80% of its maximum charging efficiency. The symbols may be configured to ensure any desired charging efficiency, such as at least at 80, 85, 90, 95, 99, or 100% of maximum charging efficiency. 
         [0040]    The symbols/indicators may be generated based on the detected and recognized position of the transmit coil  40  itself and/or the detected and recognized position of the target  108 . In at least one embodiment, the indicator  110 , indicator  112 , and/or the symbol  114  may be generated based on the detected and recognized position of the target  108 . As described above, the target  108  may be a two-dimensional or three-dimensional image or object that is located with a predefined relationship to the transmit coil  40 . When the vehicle  12  approaches the transmit coil  40  and target  108 , the target may be seen by one or more of the cameras  62 . For example, if approaching in a forward direction, at least one forward camera  64  may see the target  108 . If approaching in a rearward direction (e.g., “backing in”), at least one rear camera  66  may see the target  108 . 
         [0041]    The cameras  62  and/or a controller connected to the cameras  62  may be configured to detect and recognize the target  108 . The detection and recognition may be performed using learning algorithms. Learning algorithms may analyze a plurality of images of the target  108  from multiple angles, distances, and levels of illumination against different backgrounds in order to “learn” to detect and recognize the target  108  from new images or video streams presented to the system  100  later on. The system may also calculate/determine the distance and relative position of the target  108  from the vehicle  12  based on the detection and recognition, or by leveraging the object detection schemes described previously. Multiple different targets  108  may be analyzed and “learned” by the algorithms such that the system  100  may detect and recognize more than one target  108  shape or size. As described above, the target  108  may have any shape, such as a “T” shape, a rectangle, triangle, star, arrow, or other shapes (examples shown in  FIGS. 4A-4D ). The target  108  may also have any suitable size. In addition to size and shape, the target  108  may be or include any color or pattern. The color or pattern may further assist the learning algorithm in detecting and recognizing the target  108 . Training methods known in the art may be used to identify the target  108  in the camera field of view. Methods used might include cascaded Haar-like features to identify a given target similar to the Viola-Jones algorithm for face and object detection. 
         [0042]    In addition to detecting and recognizing the target  108 , the system  100  may also have stored therein (e.g., in the controller or other accessible memory) information regarding the relative position between the target  108  and the transmit coil  40 . This information may be in two dimensions or three dimensions, depending on the type of target  108  used. For example, if the target  108  is painted on a surface that is coplanar (or substantially coplanar) with the coil  40 , a two-dimensional relative position may be stored, while if the target  108  is on a sign that is in front of the coil  40 , a three-dimensional relative position may be stored. The relative position may be stored using a Cartesian coordinate system, such as an X-Y-Z coordinate system with X and Y serving as horizontal axes and Z serving as a vertical axis. For example, if the target  108  is painted on a surface one meter directly in front of the coil  40 , the relative position may be stored with a zero for the X-axis (left-right) and a one for the Y-axis. Since the target  108  is generally in the same plane as the coil  40 , the Z-axis value would be zero. If the target  108  was on a one meter tall sign, the Z-axis value would be one. While Cartesian coordinates are used in the examples, other coordinate systems may also be used (e.g., polar). 
         [0043]    Accordingly, the system  100  is able to detect and recognize the target  108  when it is seen by one or more of the cameras  62 . The system  100  also has stored therein the relative position of the target  108  to the transmit coil  40 . Based on the recognition of the target  108  and its known relative position to the coil  40 , the position of the coil  40  can be calculated by the system  100  (e.g., by one or more controllers therein) and the indicator  110  and/or symbol  114  can be generated and included in the augmented stream  102 . 
         [0044]    Generation of symbol  114  based on recognition of the target  108  may be particularly advantageous when the vehicle  12  is close enough to the transmit coil  40  that the coil is no longer in view of the driver and/or the cameras  62 , examples of which are shown in  FIGS. 2C-2D . Once the coil  40  is out of view of the cameras  62 , optical detection and recognition of the coil  40  cannot be performed. However, since the target  108  is still within view of the cameras  62  and the relative position between the target  108  and the coil  40  is known by the system  100 , the symbol  114  may be generated and included in the augmented stream  102  even when the vehicle  12  is covering some or all of the coil  40 . For example, by combining the skew estimation, location, and magnification of the target in the camera field of view (FoV), the system may have enough information to calculate the real-world position of the target  108  and, based on system calibration, can then draw a representation of the transmit coil  40  even as the vehicle  12  has driven over the top of the transmit coil  40 , obscuring its view. This may better enable a user to guide the vehicle  12  toward an optimal final alignment. 
         [0045]    In addition to, or instead of, generating indicator  110  and/or symbol  114  based on detection and recognition of a target  108 , the indicator  110  and/or symbol  114  may be generated based on detection and recognition of the coil  40  itself. Examples of an augmented stream  102  based on detection and recognition of the coil  40  are shown in  FIGS. 3 and 4 . The coil  40  may be detected and recognized in a manner similar to the target  108  described above, such as by using learning algorithms. The coil  40  may generally be included in a protective case or enclosure  116 . The case  116  may have any shape, such as a rectangular prism or cylinder. Since the case  116  may have a shape that is similar to shapes encountered while driving the vehicle  12 , additional identifying elements may be included in/on or attached to the case to improve detection and recognition. For example, symbols may be included on the exposed surface(s) of the case, which may be unique or easily identifiable, such as stars, emblems, logos, etc. The symbols may also have colors that are different from the case or they may emit light (e.g., visible, UV, infrared, or others) that may be detected by the system  100  (e.g., by cameras  62  or other sensors configured to detect the light). 
         [0046]    Similar to the target  10 , the dimensions (e.g., size and shape) of the coil  40  and/or its case  116  may be stored in the system  100 . Accordingly, the system  100  may detect and recognize the coil  40 . Based on the known size and shape of the coil  40 , the indicator  110  and/or symbol  114  may be generated and added to the augmented stream  102 . This process may be performed in addition to the generation based on the detection/recognition of the target  108 . However, as described above, when the vehicle  12  gets close to the coil  40 , at a certain point the coil  40  may fall out of the field of view of the camera(s)  62 . At this point, if there is no target  108  to base the calculations on, then another method or approach is needed to generate at least the symbol  114  in the augmented stream  102 . 
         [0047]    In at least one embodiment, the symbol  114  may be generated during at least a portion of the augmented stream  102  using a process known as position estimation (also known as “dead reckoning”). In general, position estimation includes calculating a current position using a previously determined position, and/or advancing a position, based upon known or estimated speeds and course/direction. Stated another way, a current position may be extrapolated from a previous known position and the speed and direction of movement between the previous position and the current position. Similarly, a future position may be extrapolated based on a known current position and the speed and direction of movement between the current and future position. 
         [0048]    Transmit coil position estimation may be used once the initial symbol  114  is placed in the augmented stream  102  by using the last known position of the vehicle  12  and/or the coil  40 , as well as the speed and course/direction of the vehicle  12 . The system  100  may record the relative position between the vehicle  12  and the coil  40  while the coil  40  is in view of one or more of the cameras  62 . When the vehicle  12  gets close enough to the coil  40  such that the coil  40  is obstructed, the system  100  may uses the vehicle&#39;s speed and direction to generate the symbol  114  without direct detection of the coil  40 . The vehicle speed may be determined in any suitable way. In one embodiment, the vehicle  12  may include an anti-lock brake system (ABS), which may monitor the number of rotations of one or more wheels on the vehicle  12 . Using the size of the wheels/tires of the vehicle, the system  100  (or other controller in the vehicle  12 ) may calculate the speed of the vehicle. The speed may also be determined from other methods, such as using a GPS system. The vehicle course or direction may be determined using any suitable method. For example, the steering wheel position may be monitored and used to determine vehicle direction. 
         [0049]    Accordingly, using the last known position (or any previously known position) of the vehicle relative  12  to the coil  40  (which may be determined using the detection/recognition methods described above), the system  100  may generate, or continue to generate, symbol  114  in the augmented stream  102  without directly viewing the coil  40 . By tapping into the vehicle&#39;s speed and direction information, which the vehicle may constantly monitor, the system  100  may continuously generate the symbol  114  as the vehicle  12  moves to position the receive coil  34  over the transmit coil  40 . 
         [0050]      FIGS. 2A-2D and 3  show several embodiments of the augmented image stream  102  which may be shown to the driver on one or more display  60  in the vehicle  12 . As described above,  FIGS. 2A-2D  show the vehicle  12  moving left to right in an overhead view.  FIG. 3  shows an image stream  102  that is split into two views, a front-facing view  118  and an overhead view  120 . As described above, the camera(s)  62  may be used to generate a large field of view around the vehicle  12 , such as at least 180° or about 360°. However, the camera(s)  62  may also be used to show a front, rear, or side view from the vehicle  12 . This view may be similar to rear-facing “back-up” cameras that assist in parking and/or avoid collisions while in reverse. 
         [0051]    As shown in  FIG. 3 , the image stream  102  may be split into a front-facing view  118  and an overhead view  120  in order to provide multiple views to assist the driver. In the embodiment shown, the front-facing view  118  is on the left and the overhead view  120  is on the right of the image stream  102 . However, the views may be flipped or a different split may be shown, such as with one view on top and the other on bottom or a diagonal split. In addition, the image stream  102  may switch from a single view to a split view (and back again) based on user preference or based on factors such as the direction of the vehicle (e.g., forward or reverse), speed of the vehicle, distance to the target  108  and/or coil  40 , or others. In the embodiment, shown in  FIG. 3 , an indicator  122  is added to the augmented stream  102  to shown which camera(s)  62  are providing the view  118  (the front camera(s)  64 , in this case) or what direction the view  118  is showing. 
         [0052]    With reference to  FIGS. 4A-4D , non-limiting examples of suitable shapes for the target  108  are shown. These shapes are merely examples, and any shape may be used that can be detected and recognized by the system  100 . The examples shown are for a two-dimensional or substantially flat target  108 , such as one applied to a surface in front of, behind, or next to the transmit coil  40 . In  FIGS. 4A and 4B , the target is shown as a triangle.  FIG. 4A  shows an equilateral triangle  202 , while  FIG. 4B  shows an isosceles triangle  204 . Other triangle shapes could also be used, such as a right triangle or a triangle including an obtuse angle.  FIG. 4C  shows an example of an arrow-shaped target  206 .  FIG. 4D  shows an example of a cross-shaped or “plus sign” shaped target  208 . As described above, the target  108  may have one or more colors and/or patterns that cause it to stand out to the driver and/or to the detection and recognition system  100 . 
         [0053]    While the imaging and object recognition system  100  is described with respect to assisting a driver in locating a transmit coil  40  and positioning the receive coil  34  of the vehicle  12  over the transmit coil  40 , it may be used in any locating and positioning application. For example, the system  100  may be used in other vehicle applications, such as in detecting and recognizing parking spots, wired EV chargers, or other items. The system  100  may assist in pulling up to or backing up to items to be towed, such as locating and positioning a vehicle trailer hitch for attaching to a trailer. The system  100  may also be used for non-vehicle applications. 
         [0054]    The processes, methods, or algorithms disclosed herein can be deliverable to/implemented by a processing device, controller, or computer, which can include any existing programmable electronic control unit or dedicated electronic control unit. Similarly, the processes, methods, or algorithms can be stored as data and instructions executable by a controller or computer in many forms including, but not limited to, information permanently stored on non-writable storage media such as ROM devices and information alterably stored on writeable storage media such as floppy disks, magnetic tapes, CDs, RAM devices, and other magnetic and optical media. The processes, methods, or algorithms can also be implemented in a software executable object. Alternatively, the processes, methods, or algorithms can be embodied in whole or in part using suitable hardware components, such as Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), state machines, controllers or other hardware components or devices, or a combination of hardware, software and firmware components. 
         [0055]    While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes may include, but are not limited to cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, embodiments described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and can be desirable for particular applications.