Patent Publication Number: US-9415953-B2

Title: System and method of material handling using one imaging device on the receiving vehicle to control the material distribution into the storage portion of the receiving vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation In Part application of PCT International Application PCT/US2013/025572, filed Feb. 11, 2013, titled SYSTEM AND METHOD OF MATERIAL HANDLING USING ONE IMAGING DEVICE ON THE RECEIVING VEHICLE TO CONTROL THE MATERIAL DISTRIBUTION INTO THE STORAGE PORTION OF THE RECEIVING VEHICLE, which claims the priority of U.S. Provisional Application 61/597,346, filed Feb. 10, 2012, and U.S. Provisional Application 61/597,374, filed Feb. 10, 2012, and U.S. Provisional Application 61/597,380, filed Feb. 10, 2012, all are incorporated by reference herein. 
    
    
     JOINT RESEARCH AGREEMENT 
     This application resulted from work performed under or related to a joint research agreement between Carnegie Mellon University and Deere &amp; Company, entitled “Development Agreement between Deere &amp; Company and Carnegie Mellon University,” dated Jan. 1, 2008 and as such is entitled to the benefits available under 35 U.S.C. §103(c). 
     FIELD OF THE INVENTION 
     This invention relates to a method and stereo vision system for facilitating the unloading of material from a vehicle. 
     BACKGROUND 
     Certain prior art systems may attempt to use global positioning system (GPS) receivers to maintain proper spacing between two vehicles during the unloading or transferring of agricultural material or other materials, such as coal or other minerals, between the vehicles. However, such prior art systems are susceptible to misalignment of the proper spacing because of errors or discontinuities in the estimated position of the GPS receivers. For example, one or more of the GPS receivers may misestimate its position because of electromagnetic interference, multipath propagation of the received satellite signals, intermittent reception of the satellite signals or low received signal strength of the satellite signals, among other things. If the vehicles use cameras or other imaging devices in an outdoor work area, such as an agricultural field, the imaging devices may be subject to transitory sunlight, shading, dust, reflections or other lighting conditions that can temporarily disrupt proper operation of the imaging devices; hence, potentially produce errors in estimated ranges to objects observed by the imaging devices. Thus, there is a need for an improved system for managing the unloading of agricultural material from a vehicle to compensate for or address error in the estimated positions or alignment of the vehicles. 
     SUMMARY OF THE INVENTION 
     The system and method facilitates the transfer of agricultural material from a transferring vehicle (e.g., harvesting vehicle) to a receiving vehicle (e.g., grain cart). The system and method comprises a receiving vehicle, which has a propelled portion for propelling the receiving vehicle and a storage portion for storing agricultural material and a transferring vehicle for transferring harvested agricultural material into the storage portion of the receiving vehicle. 
     Two embodiments of the present invention include one or two primary imaging devices on only one vehicle, either the receiving vehicle or the transferring vehicle. A first embodiment mounts only one primary imaging device on the propelled portion of the receiving vehicle and no imaging devices mounted on the transferring vehicle. A second embodiment mounts one or two imaging devices on the transferring vehicle and no imaging devices on the receiving vehicle. 
     The receiving vehicle and/or the transferring vehicle of any of the above mentioned embodiments can include as an image processing module having a container module that can identify a container perimeter of the storage portion in at least one of the collected first image data and the collected second image data (where a second imaging device is incorporated into the system configuration). The image processing can also include a spout module that is adapted to identify a spout of the transferring vehicle in the collected image data (collected first image data, collected second image data, or both). The image processing module can include an arbiter (e.g., image data evaluator) that determines whether to use the first image data, the second image data or both (where a second imaging device is incorporated into the system configuration), based on an evaluation of material variation of intensity of pixel data or material variation in ambient light conditions during a sampling time interval. In a system with only one imaging device, the arbiter either not activated, is not incorporated into the system, or includes logic that passes the only collect image to the next function. The image processing module can also include an alignment module that is adapted to determine the relative position of the spout and the container perimeter, and to generate command data to the propulsion controller of the transferring vehicle or the receiving vehicle or both to propel (accelerate or decelerate) the storage portion in cooperative alignment with the transferring vehicle such that the spout is aligned within a central zone (or other target zone) of the container perimeter. The present invention of any of the embodiment can include a steering controller that is associated with a steering system of the transferring vehicle or the receiving vehicle or both for steering the receiving vehicle in accordance with the cooperative alignment with the transferring vehicle based on input from alignment module. The transferring vehicle can include a material profile module to develop a profile of the material within the storage portion of the receiving vehicle to facilitate vehicle cooperative alignment and spout adjustment. 
     In operation, a method for facilitating the transfer of material from a transferring vehicle having a material distribution end to a receiving vehicle having a bin to the store transferred material, the method comprising the steps of: 
     a. identifying and locating the bin; 
     b. detecting a representation of the fill level or volumetric distribution of the material in the bin; 
     c. aligning the material distribution end over a current target area of the bin requiring the material (wherein a current target area can be an initial target area the material distribution end is positioned when the filling of material begins); 
     d. determining subsequent target areas of the bin that require material based on the representation of the fill level or volumetric distribution of the material in the bin and a desired fill pattern (such as front-to-back, back-to-front, center-to-front-to-back, center-to-back-to-front) to fill the bin; 
     e. transferring the material from the transferring vehicle to the current target area of the bin of the receiving vehicle; 
     f. detecting when the current target area of the bin is filled with the material; and 
     g. repeating steps c-f until the subsequent target areas of the bin are filled per the desired fill pattern. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of one embodiment of a machine vision-augmented guidance system for a transferring vehicle for facilitating the unloading of agricultural material from the transferring vehicle (e.g., combine); 
         FIG. 2  is a block diagram of another embodiment of a machine vision-augmented guidance for a transferring vehicle for facilitating the unloading of agricultural material from the transferring vehicle (e.g., a self-propelled forage harvester); 
         FIGS. 3A and 3B  are block diagrams of embodiments of a machine vision-augmented guidance system for a receiving vehicle for facilitating the unloading of agricultural material from a transferring vehicle to the receiving vehicle (e.g., grain cart and tractor); 
         FIG. 4A  illustrates a top view of an imaging devices mounted on a transferring vehicle and facing toward a receiving vehicle; 
         FIG. 4B  illustrates a view in a horizontal plane as viewed along reference line  4 B- 4 B in  FIG. 4A ; 
         FIG. 5A  illustrates a top view of a single imaging device (e.g., a stereo vision system) mounted on a receiving vehicle and facing a storage portion of the receiving vehicle; 
         FIG. 5B  illustrates a view in a horizontal plane as viewed along reference line  5 B- 5 B in  FIG. 5A ; 
         FIG. 5C  illustrates a two-dimensional representation of various possible illustrative distributions of material in the interior of a container or storage portion, consistent with a cross-sectional view along reference line  5 D- 5 D in  FIG. 5B ; 
         FIG. 5D  is a plan view of a transferring vehicle and a receiving vehicle, where the transferring vehicle is aligned within a matrix of possible offset positions; 
         FIG. 6  illustrates a block diagram of a container module or an image processing module; 
         FIG. 7  is a block diagram of a spout module or an image processing module; 
         FIG. 8  is a flow chart of a method for operating a mode controller of a machine vision-augmented guidance system for facilitating the unloading of agricultural material from a vehicle (e.g., combine); 
         FIG. 9  is a flow chart of yet another method for a machine vision-augmented guidance system for facilitating the unloading of agricultural material from a vehicle (e.g., combine); 
         FIG. 10  is a flow chart of another method for a machine vision-augmented guidance system for facilitating the unloading of agricultural material from a vehicle (e.g., combine); and 
         FIG. 11  is a schematic illustrating the data flow and processing by the image processing module from raw images to vehicle commands. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In accordance with one embodiment of the present invention that requires imaging devices only on the receiving vehicle  79 ,  FIGS. 3A, 5A and 5B  show a machine vision augmented guidance system  311  for a receiving vehicle  79  for managing the unloading of agricultural material (e.g., grain) from the transferring vehicle  91  (e.g., combine) to a receiving vehicle  79  (e.g., grain cart or wagon).  FIG. 5A  illustrates a top view of an exemplary transferring vehicle  91  and a receiving vehicle  79  configuration.  FIG. 5B  illustrates a side view of an exemplary transferring vehicle  91  and a receiving vehicle  79  configuration of  FIG. 5A . For example, a stereo imaging system augments satellite navigation receivers or location-determining receivers  142  for guidance of receiving vehicle  79 . The imaging device  10  has a field of view  277 , indicated by the dashed lines. The boundaries of the field of view  277  are merely shown for illustrative purposes and will vary in actual practice. The system  311  can comprise a imaging device  10  coupled to an image processing module  18 . Embodiments of imaging device  10  may comprise a stereo camera. Like element numbers provided for herein have the same function or meaning. Though the example of transferred material disclosed herein is agricultural material, the invention is not to be limited to agricultural material and is applicable to other materials such as coal and other minerals. 
     Now turning to  FIG. 11  that illustrates the data flow and processing by the image processing module  18  from the raw images to the receiving vehicle commands. The components and modules will be discussed in detail below. The dashed lines represent optional steps and/or modules. Raw images are collected by the imaging device  10  (e.g. camera being stereo). Raw images are processed through the image rectifier  101  to create rectified images. Rectified images are processed by the arbiter or image data evaluator  25  to provide an image quality score for the rectified image to determine if the image should be used in further processing by the alignment module  24 . Rectified images are also processed by the container (identification) module  20  and material profile module  27 . Rectified images can be processed by a disparity generator  103  to generate range data with regards to the container or bin  85  characteristics, such as distances from and dimensions of edges, length, and depth. Rectified images can also be processed in conjunction with disparity images by the spout localizer or module  22  when a disparity image generator  103  is present. Otherwise, spout localizer  22  will only use the data stored in vehicle model  1000 , which includes, but not limited to, data on the transferring vehicle  91 , dimensions of spout  89 , spout kinematic model and container information. Spout localizer  22  also requires data about the vehicle state information, which includes, but not limited to, transferring vehicle speed, spout angle(s), auger drive on/off status, and relative Global Positioning Satellite position of receiving vehicle  79  if machine synchronization is present. Spout localizer  22  output (e.g. spout orientation) is input into container identification module  20  and processed in conjunction with rectified images and disparity images (if provided) by container identification module  20  and container dimensions provided by the vehicle model  1000  to determine container location and dimensions. Rectified images and disparity images (if provided) are processed in conjunction with container location and dimensions data from container identification module  20  by material profile module  27  to generate a fill profile of the container  85 . Alignment module  24  processes data generated by the container identification module  20 , material profile module  27 , vehicle dimensions provided by the vehicle model  1000  in conjunction with the vehicle state information to generate vehicle commands such as receiving vehicle  79  speed/steering, spout position, auger drive on/off status, and speed/steering of the receiving vehicle  79  if machine synchronization is present to reposition the spout end  87  over the appropriate open area of the container  85  for even, uniform distribution of the agricultural material in container  85 . 
     Now returning to  FIG. 3A  that comprises the first imaging device  10  the image processing module  18 , the user interface processing module  26 , the gateway  29 , a second location-determining receiver  142 , a second wireless communications device  148 , the slave controller  159  among other devices illustrated in  FIG. 3A . In one embodiment, the first imaging device  10  is mounted on the propelled portion  75  (e.g., tractor) of the receiving vehicle  79  facing backwards towards the storage portion  93  (e.g., cart) or container  85 . The second wireless communications device  148  of the receiving vehicle  79  is adapted for communicating data with the first communications device  48  of the transferring vehicle  91  of  FIG. 4A . The second location-determining receiver  142  provides position data, location data, altitude, velocity, or acceleration data. 
     The slave controller  159  can operate in a slave mode or follower mode under the control of the master controller  59 . The auto-guidance module  155  and the coordination module  157  within the slave controller  159  provide guidance of the receiving vehicle  79 , consistent with location data and a path plan, or with other guidance data or command data from the transferring vehicle  91 . 
     The second wireless communications device  148  is coupled to the vehicle data bus  60 . In  FIG. 3A , the system  311  for a receiving vehicle can be used in conjunction with the system  11  or  111  of the transferring vehicle  91  of  FIG. 1  or, or independently of any transferring vehicle. The wireless devices  48 ,  148  may exchange or communicate position data, relative position data, command data, or control data for controlling, adjusting or coordinating the position and orientation of the vehicles; more particularly, the position and the orientation of the spout  89  or spout end  87  over the opening  83  of the container  85 . The communicated data between the wireless communications devices  48 ,  148  may comprise any of the following data: (1) position data or location data from either location determining receiver  42  or  142 , (2) command or guidance data from an image processing module  18  on the transferring vehicle  91  or receiving vehicle  79 , (3) command or guidance data from the master controller  59  or coordination module  47 , (4) command or guidance data from the slave controller  159  or coordination module  157  or (5) alignment data (e.g., relative position of the imaging devices, relative position of reference points on the vehicles, and relative alignment between the spout  89  and container perimeter  81 ) from the alignment module  24 . For example, the imaging processing module  18  or alignment module  24  may use first location data of a first location determining receiver  42  and second location data of a second location determining receiver  142  to determine a relative position or spatial offset between the two vehicles (or a relative position) of the first imaging device  10  and the second imaging device  12  and to determine a relative alignment between the spout  89  and the container perimeter  81 . 
     The system  311  of  FIG. 3A  may support different configurations or combinations of electronic systems (e.g.,  11  and  311  or  111  and  311 ) at the transferring vehicle  91  and receiving vehicle  91 . In a first configuration, only one imaging device  10  is on the receiving vehicle  79  may be used instead of, or with, one or more imaging devices  10 ,  12  on the transferring vehicle  91 . In a second configuration, the system  311  of  FIG. 3A  may provide collected image processing data from the receiving vehicle  79  to the transferring vehicle  91  via the transmission of the collected image processing data from the second wireless communications device  148  to the first wireless communications device  48 . Here, in a second configuration, the collected imaging processing data from the receiving vehicle  79  may be referred to as supplementary data, complementary image data, or additional image data. The additional image data may provide additional perspective or viewpoints that can supplement the image data collected by the transferring vehicle  91 . For example, the additional image data may provide more accurate or supplement image data where the image data collected by the transferring vehicle  91  is affected by moisture (e.g., on its lens), dust, poor ambient lighting, glare or reflections that do not similarly impair or impact the additional image data. 
     The optional odometry sensor  440  may be coupled to the vehicle data bus  60  or the implement data bus  58 . The inertial sensor  442  may comprise one or more accelerometers, gyroscopes or other inertial devices coupled to the vehicle data bus  31  or the implement data bus  60 . 
     The distributed fill state sensors  149  ( FIG. 3A ) may comprise optical level sensors (not shown) distributed at different height levels within or around the container  85 , piezoelectric mass sensors distributed to measure mass of the agricultural material in different volumes or on different floor areas (e.g., of a false vertically movable floor) of the container  85 , or piezoresistive mass sensors distributed to measure mass of the agricultural material in different volumes or on different floor areas of the container  85 , for example. 
       FIG. 5A  illustrates a top view of a transferring vehicle  91  and a receiving vehicle  79 . Like reference numbers indicate like elements in  FIG. 5A  and  FIG. 4A .  FIG. 5A  shows an imaging device  10  on the rear of the propulsion unit  75  (e.g., tractor) or the receiving vehicle  79 . The imaging device  10  has a field of view  277  indicated by the dashed lines. In  FIG. 5A , the spout  89  or spout end  87  is generally aligned over a central zone  83 , central region or target area of the storage unit  93  or container  85  for unloading material from the transferring vehicle  91  to the receiving vehicle  79 . Similarly, the transferring vehicle  91  and the receiving vehicle  79  are aligned in position as shown, and even as the vehicles  79 ,  91  move with coordinated headings or generally parallel headings and with no or minimal relative velocity with respect to each other. In  FIG. 5A , the image processing module  18  can estimate the distance or range from the imaging device  10  to an object in the image, such as the spout  89 , the spout end  87 , the container perimeter  81 , the level or profile of agricultural material in the container  85  (e.g., at various positions or coordinates within the container  85 ). The term “bin” can be used in place of the term “container.” 
       FIG. 5B  illustrates a view in a horizontal plane as viewed along reference line  5 B- 5 B in  FIG. 5A . In one embodiment, the first imaging device  10  is mounted on the receiving vehicle  79  on a first support  571  (e.g., monopole with tilt or pan adjustment) to provide a first downward field of view  577  or a first down-tilted field of view. 
     In an alternate embodiment, the first support  571  comprises an adjustable mast or telescopic mast that is controlled by a mast controller  674  to remotely adjust the height, tilt angle, down-tilt angle, rotation angle, or pan angle to provide reliable image data for processing by the image processing module  18 . Similarly, the second support  573  comprises an adjustable mast or telescopic mast that is controlled by a mast controller ( 674 ) to remotely adjust the height, tilt angle, down-tilt angle, rotation angle, or pan angle to provide reliable image data for processing by the image processing module  18 . 
       FIG. 5C  illustrates a two-dimensional representation of various possible illustrative distributions of material in the container  85 , consistent with a view along reference line  5 C in  FIG. 5A . In one configuration, the y axis is coincident with the longitudinal axis or direction of travel of the container, the z axis is coincident with the height of material in the container, and the x axis is perpendicular to the direction of travel of the container, where the x, y and z axes are generally mutually orthogonal to each other. 
     In the chart of  FIG. 5C , the vertical axis is the mean height (f)  500  of the material in the container  85 , the horizontal axis represents the longitudinal axis (y)  502  of the container  85 . The maximum capacity  504  or container capacity is indicated by the dashed line on the vertical axis. The front  512  of the container  85  is located at the origin, whereas the back  514  of the container  85  is located on the vertical axis. 
       FIG. 5C  shows three illustrative distributions of material within the container  85 . The first distribution is a bimodal profile  508  in which there are two main peaks in the distribution of material in the container  85 . The bimodal profile  508  is shown as a dotted line. The bimodal profile  508  can occur where the spout angle adjustment is governed by an electro-hydraulic system with non-proportional valves. 
     The second distribution is the front-skewed modal profile  510  in which there is single peak of material toward the front of the container  85 . The front-skewed modal profile  510  is shown as alternating long and short dashes. The second distribution may occur where the volume or length (y) of the container  85  is greater than a minimum threshold and where the relative alignment between the spout end  87  and the container  85  is generally stationary during a substantial portion of unloading of the material. 
     The third distribution is the target profile  508  which may be achieved by following a suitable fill strategy as disclosed in this document. For example, during unloading, the spout angle may be adjusted to promote uniform distribution of the agricultural material in the container  85 . Further, the lateral offset (Δ) or fore/aft offset (Φ or φ) between the vehicles  79 ,  91  may be adjusted in accordance with a matrix (e.g., x, y coordinate matrix of equidistant point locations of the transferring vehicle relative to a constantly spaced position point of the receiving vehicle) of relative unloading positions, particularly for longer or wider containers that cannot be uniformly filled from a single, relative unloading point between the vehicles  79 ,  91 . 
       FIG. 5D  is a plan view of a transferring vehicle  91  and a receiving vehicle  79 , where the transferring vehicle  91  is aligned within a matrix  500  of possible offset positions  502 ,  504  between the transferring and receiving vehicle  79 . Each offset position  502 ,  504  may be defined in terms of a combination of a unique lateral offset (Δ) and a unique fore/aft offset (Φ or φ) between the vehicles  79 ,  91 . As shown, the matrix  500  is a two-dimensional, 2×3 (2 columns by 3 rows) matrix of possible offset positions  502 ,  504 . Although six possible matrix positions  502 ,  504  are shown, in alternate embodiments the matrix  500  may consistent of any number of possible offset positions greater than or equal to two. Here, the transferring vehicle  91  occupies a current offset position  504  in the first column at the second row of the matrix  500 , whereas the other possible offset positions  502  are not occupied by the transferring vehicle  91 . As directed by any of the systems ( 11 ,  111 ,  311 ), the imaging processing module  18 , or the master controller  59  of the transferring vehicle  91  can shift to any unoccupied or other possible offset positions  502  within the matrix  500  to promote or facilitate an even distribution of agricultural material within the container  85  or storage portion of the receiving vehicle  79 . The spatial offset between the transferring vehicle  91  and the receiving vehicle  79  may be adjusted in accordance with the matrix  500  or another matrix of preset positions of spatial offset to promote even distribution of agricultural material in the storage portion of the receiving vehicle  79 , where any matrix is associated with a unique, relative lateral offset (Δ) and fore/aft offset (Φ or φ) between the vehicles  79 ,  91 . 
     In accordance with another embodiment of the present invention that requires imaging devices only on the transferring vehicles,  FIGS. 1, 3B, 4A and 4B  show a machine vision augmented guidance system  11  for a transferring vehicle  91  for managing the unloading of agricultural material (e.g., grain) from the transferring vehicle  91  (e.g., combine) to a receiving vehicle  79  (e.g., grain cart or wagon), and  FIGS. 2, 3B, 4A and 4B  show a machine vision augmented guidance system  111  for a transferring vehicle  91  for managing the unloading of agricultural material (e.g., grain) from the transferring vehicle  91  (e.g., self-propelled forge harvester) to a receiving vehicle  79  (e.g., grain cart or wagon).  FIG. 4A  illustrates a top view of an exemplary transferring vehicle  91  and a receiving vehicle  79  configuration. For example, a stereo imaging system augments satellite navigation receivers or location-determining receivers  42  for guidance of one or more vehicles. The first imaging device  10  has a first field of view  77 , indicated by the dashed lines. The second imaging device  12  has a second field of view  177 , indicated by the dashed lines. The boundaries of the fields of view  77 ,  177  are merely shown for illustrative purposes and will vary in actual practice. The system  11  can comprises a first imaging device  10  and a second imaging device  12  coupled to an image processing module  18 . Embodiments of first imaging device  10  may comprise a primary stereo camera or a monocular camera, while the second imaging device  12  may comprise a secondary stereo camera or a monocular camera. In one configuration, the second imaging device  12  is a stereo camera and can be optional and provides redundancy to the first imaging device  10  in case of failure, malfunction or unavailability of image data from the first imaging device  10  when the first field of view  77  of the first imaging device  10  is sufficient to view within container  85 . In one configuration, the second imaging device is monocular and is required for a stereo image of the container  85  when used in conjunction with an image from a monocular first imaging device  10  with the first field of view  77  sufficient to view within container  85 . Though the example of transferred material disclosed herein is agricultural material, the invention is not to be limited to agricultural material and is applicable to other materials such as coal and other minerals.  FIG. 4A  shows a first imaging device  10  on the transferring vehicle  91  (e.g., combine) and a second imaging device  12  on a spout  89  of the transferring vehicle  91 . The second imaging device  12  can be optional if the first imaging device  10  is a stereo camera and the first field of view  77  of the first imaging device  10  is sufficient to view within container  85 . The spout  89  may also be referred to as an unloading auger. The spout end  87  may be referred to as a boot. In  FIG. 4A , the spout  89 , or the spout end  87 , is generally aligned over a central zone  83 , central region or target area of the storage container  85  (of the receiving vehicle  79 ) for unloading material from the transferring vehicle  91  to the receiving vehicle  79 . Similarly, the transferring vehicle  91  and the receiving vehicle  79  are aligned in position as shown, regardless of whether the vehicles move together in a forward motion (e.g., with coordinated or tracked vehicle headings) during harvesting, as is typical, or are stationary. During unloading, the master controller  59  ( FIGS. 1 and 2 ) and slave controller  159  ( FIG. 3B ) facilitate maintenance of a generally uniform spatial offset (e.g., a generally static offset that varies only within a predetermined target tolerance) between the vehicles  91 ,  79 , subject to any incremental adjustment of the offset for uniform filling of the container  85 . The master controller  59  and slave controller  159  support maintenance of a uniform fore/aft offset (Φ) or (φ) and a lateral offset (Δ). 
     Now returning to  FIG. 1 , the transferring vehicle  91  may be equipped with a rotation sensor  116  (e.g., rotary position sensor) to measure the rotation angle of the spout. For a spout-mounted imaging device (e.g., second imaging device  12  on the spout as shown in  FIG. 4A ), the rotation angle of the spout  89  may be used to facilitate fusion of image data from the first imaging device  10  and the second imaging device  12 , or to construct stereo image data where the first imaging device  10  and the second imaging device  12  individually provide monocular image data for the same scene or object. 
     In any arrangement of imaging devices  10 ,  12  disclosed herein where the fields of view  77 ,  177  overlap, data fusion of image data from a first imaging device  10  and a second imaging device  12  enables the image processing module  18  to create a virtual profile of the material distribution level inside the storage portion  85 , even when the entire surface of the agricultural material is not visible to one of the two imaging devices  10 ,  12 . Even if the second imaging device  12  is not mounted on the spout  89  in certain configurations, the rotation sensor  116  may facilitate using the spout end  87  as a reference point in any collected image data (e.g., for fusion, virtual stitching or alignment of image data from different imaging devices.) The virtual profile of the entire surface of the agricultural material in the storage portion  93  enables the system  11 ,  111 ,  411  or imaging module  18  to intelligently execute a fill strategy for the storage portion  93  of the receiving vehicle. 
     The first imaging device  10  and the second imaging device  12  may provide digital data format output as stereo video image data or a series of stereo still frame images at regular or periodic intervals, or at other sampling intervals. Each stereo image (e.g., the first image data or the second image data) has two component images of the same scene or a portion of the same scene. For example, the first imaging device  10  has a first field of view  77  of the storage portion  93  of the receiving vehicle  79 , where the first field of view  77  overlaps at least partially with a second field of view  177  of the second imaging device  12  (if present). 
     In one configuration, an optical sensor  110 ,  112  comprises a light meter, a photo-sensor, photo-resistor, photo-sensitive device, a cadmium-sulfide cell, charge-couple device, or complementary metal oxide semi-conductor. A first optical sensor  110  may be associated with the first imaging device  10 ; a second optical sensor may be associated with the second imaging device  12 . The first optical sensor  110  and the second optical sensor  112  each may be coupled to the image processing module  18 . The optical sensor  110 ,  112  provides a reading or level indicative of the ambient light in the field of view of its respective imaging device  10 ,  12 . 
     The image processing module  18  may be coupled, directly or indirectly, to lights  14  on a vehicle (e.g., transferring vehicle) for illumination of a storage container  85  ( FIG. 4A ) and/or spout  89  ( FIG. 4A ). For example, the image processing module  18  may control drivers, relays or switches, which in turn control the activation or deactivation of lights  14  on the transferring vehicle. The image processing module  18  may activate the lights  14  on the vehicle for illumination of the storage container  85  ( FIG. 4A ), spout  89  or both if an optical sensor  110 ,  112  or light meter indicates that an ambient light level is below a certain minimum threshold. In one configuration the optical sensor  110 ,  112  face toward the same direction as the lens or aperture of the imaging devices  10 ,  12 . 
     In one embodiment, the auger rotation system  16  of  FIG. 1  may comprise: (1) a rotation sensor  116  for sensing a spout rotation angle (α in  FIG. 4A  and β in  FIG. 4C ) of the spout  89  with respect to one or more axes of rotation and (2) an actuator  216  for moving the spout  89  to change the spout rotation angle; hence, the spout position with respect to the receiving vehicle  79  or its storage container  85 . The rotation actuator  210  may comprise a motor, a linear motor, an electro-hydraulic device, a ratcheting or cable-actuated mechanical device, or another device for moving the spout  89 , or the spout end  87 . The spout rotation angle may comprise a simple angle, a compound angle or multi-dimensional angles that is measured with reference to a reference axis parallel to the direction of travel of the transferring vehicle. 
     If the rotation actuator  210  comprises an electro-hydraulic device, the use of proportional control valves in the hydraulic cylinder of the electro-hydraulic device that rotates the spout (or changes the spout rotation angle) facilitates finer adjustments to the spout angle (e.g., a) than otherwise possible. Accordingly, proportional control valves of the electro-hydraulic device support or rotation actuator  201  an even profile or distribution of unloaded agricultural material within the storage portion  93  or container  85 . Many commercially available combines are typically equipped with non-proportional control valves for controlling spout angle or movement of the spout  89 ; electro-hydraulic devices with non-proportional control valves can fill the storage container with an inefficient multi-modal or humped distribution (e.g.,  508 ) of agricultural material with local high areas and local low areas, as depicted in  FIG. 5C , for example. 
     A vehicle controller  46  of  FIG. 1  may be coupled to the vehicle data bus  60  to provide a data message that indicates when the auger drive  47  for unloading agricultural material from the transferring vehicle is activate and inactive. The auger drive  47  may comprise an auger, an electric motor for driving the auger, and a rotation sensor for sensing rotation or rotation rate of the auger or its associated shaft. In one embodiment, the auger (not shown) is associated with a container for storing agricultural material (e.g., a grain tank) of a transferring vehicle  91  (e.g., a combine). If the vehicle controller  46  (e.g., auger controller) indicates that the auger of the transferring vehicle is rotating or active, the imaging processing module  18  activates the spout module  22  and container module  20 . Thus, the auger rotation system  16  may conserve data processing resources or energy consumption by placing the container module  20  and the spout module  22  in an inactive state (or standby mode) while the transferring vehicle is harvesting, but not unloading, the agricultural material to the receiving vehicle. 
     Spout controller  54  of  FIG. 2  may be coupled to the vehicle data bus  60  to provide a data message that indicates when spout will discharge or distribute material based on data from the rotation actuator  260 , tilt actuator  261 , and deflector actuator  264 . 
     In  FIGS. 1 and 2 , the imaging processing module  18  or any other controller may comprise a controller, a microcomputer, a microprocessor, a microcontroller, an application specific integrated circuit, a programmable logic array, a logic device, an arithmetic logic unit, a digital signal processor, or another data processor and supporting electronic hardware and software. As mentioned above, in one embodiment the image processing module  18  comprises a container module  20 , a spout module  22 , an alignment module  24 , a material profile module  27 , and an arbiter  25 . 
     The image processing module  18  may be associated with a data storage device  19 . The data storage device  19  may comprise electronic memory, non-volatile random access memory, a magnetic disc drive, an optical disc drive, a magnetic storage device or an optical storage device, for example. If the container module  20 , the spout module  22  and the alignment module  24 , material profile module  27  and arbiter  25 , are software modules they are stored within the data storage device  19 . 
     The container module  20  identifies a set of two-dimensional or three dimensional points (e.g., in Cartesian coordinates or Polar coordinates) in the collected image data or in the real world that define at least a portion of the container perimeter  81  ( FIG. 4A ) of the storage portion  85  ( FIG. 4A ). The set of two-dimensional or three dimensional points correspond to pixel positions in images collected by the first imaging device  10 , the second imaging device  12 , or both. The container module  20  may use or retrieve container reference data. 
     The container reference data comprises one or more of the following: reference dimensions (e.g., length, width, height), volume, reference shape, drawings, models, layout, and configuration of the container  85 , the container perimeter  81 , the container edges  181 ; reference dimensions, reference shape, drawings, models, layout, and configuration of the entire storage portion  93  of receiving vehicle; storage portion wheelbase, storage portion turning radius, storage portion hitch configuration of the storage portion  93  of the receiving vehicle; and distance between hitch pivot point and storage portion wheelbase. The container reference data may be stored and retrieved from the data storage device  19  (e.g., non-volatile electronic memory). For example, the container reference data may be stored by, retrievable by, or indexed by a corresponding receiving vehicle identifier in the data storage device  19  of the transferring vehicle system  11 . For each receiving vehicle identifier, there can be a corresponding unique container reference data stored therewith in the data storage device  19 . 
     In one embodiment, the transferring vehicle  91  receives a data message from the receiving vehicle  79  in which a vehicle identifier of the receiving vehicle is regularly (e.g., periodically transmitted). In another embodiment, the transferring vehicle  91  interrogates the receiving vehicle  79  for its vehicle identifier or establishes a communications channel between the transferring vehicle  91  and the receiving vehicle  79  in preparation for unloading via the wireless communication devices  48 ,  148 . In yet another embodiment, the receiving vehicle transmits its vehicle identifier to the transferring vehicle  91  when the receiving vehicle  79  approaches the transferring vehicle within a certain radial distance. In still another embodiment, only one known configuration of receiving vehicle  79  is used with a corresponding transferring vehicle  91  and the container reference data is stored or saved in the data storage device  19 . In the latter embodiment, the transferring vehicle is programmed, at least temporarily, solely for receiving vehicles with identical containers, which are identical in dimensions, capacity, proportion and shape. 
     In one configuration, the container module  18  identifies the position of the controller as follows. If the linear orientation of a set of pixels in the collected image data conforms to one or more edges  181  of the perimeter  81  ( FIG. 4A ) of the container  85  ( FIG. 4A ) as prescribed by the container reference data, the position of the container has been identified. A target zone, central region or central zone of the container opening  83  of the container  85  can be identified by dividing (by two) the distance (e.g., shortest distance or surface normal distance) between opposite sides of the container, or by identifying corners of the container and where diagonal lines that intercept the corners intersect, among other possibilities. In one configuration, the central zone may be defined as an opening (e.g., circular, elliptical or rectangular) in the container with an opening surface area that is greater than or equal to the cross-sectional surface area of the spout end by a factor of at least two, although other surface areas fall within the scope of the claims. 
     The spout module  22  identifies one or more of the following: (1) the spout pixels on at least a portion of the spout  89  ( FIG. 4A ), or (2) spout end pixels that are associated with the spout end  87  of the spout  89  ( FIG. 4A ). The spout module  22  may use color discrimination, intensity discrimination, or texture discrimination to identify background pixels from one or more selected spout pixels with associated spout pixel patterns or attributes (e.g., color or color patterns (e.g., Red Green Blue (RGB) pixel values), pixel intensity patterns, texture patterns, luminosity, brightness, hue, or reflectivity) used on the spout  89  or on the spout end  87  of the spout  89  for identification purposes. 
     The alignment module  24 , the master controller  59 , or both estimate or determine motion commands at regular intervals to maintain alignment of the spout  56  over the central zone, central region or target of the container  85  for unloading agricultural material. The alignment module  24 , the master controller  59 , or both, may send commands or requests to the transferring vehicle  91  with respect to its speed, velocity or heading to maintain alignment of the position of the transferring vehicle  91  with respect to the receiving vehicle  79 . For example, the alignment module  24  may transmit a request for a change in a spatial offset between the vehicles to the master controller  24 . In response, the master controller  59  or the coordination module  57  ( FIG. 1 ) transmits a steering command or heading command to the steering controller  32 , a braking or deceleration command to a braking system  34 , and a propulsion, acceleration or torque command to a propulsion controller  40  to achieve the target spatial offset or change in spatial offset. Further, similar command data may be transmitted via the wireless communication devices  48 ,  148  to the receiving vehicle  79  for observational purposes or control of the receiving vehicle via its steering system controller  32 , its braking controller  36 , and its propulsion controller  40  of the system  411  of  FIG. 3B . 
     In another configuration, the alignment module  24  or image processing module  18  may regularly or periodically move, adjust or rotate the target zone or central zone during loading of the container  85  of the receiving vehicle  79  to promote even filling, a uniform height, or uniform distribution of the agricultural material in the entire container  85 , where the image processing module  18  identifies the fill state of the agricultural material in the image data from the material profile module  27  or receives fill state data from distributed fill state sensors  149  in  FIG. 3A  (associated with the container  85 ) via the wireless communication devices  148 ,  149 . 
     The imaging module  18  may comprise material profile module  27  or a fill level sensor for detecting a one-dimensional, two-dimensional or three-dimensional representation of the fill level or volumetric distribution of the agricultural material in the container  85  or storage portion  93 . For example,  FIG. 5C  shows various illustrative two-dimensional representations of the fill state of the container  85 , or the distribution of agricultural material in the container  85 , where  FIG. 5C  will be described later in detail. 
     In one configuration illustrated in  FIG. 1 , the coordination module  57  or the steering controller  32  adjusts the relative position (of offset) of the transferring vehicle  91  to the receiving vehicle  79 . The alignment module  24 , the coordination module  57  and the auger rotation system  16  may control the relative position of the spout  89  or the spout end  87  to the container perimeter  81  to achieve an even fill to the desired fill level. For example, rotation actuator  210  or the auger rotation system  16  may adjust the spout angle (e.g., a first spout angle (α), a second spout angle (β), or a compound angle (α and β) that the spout  89  makes with respect to a reference axis or reference coordinate system associated with the transferring vehicle  91  or a generally vertical plane associated with the direction of travel of the transferring vehicle  91 , where the spout  89  meets and rotates with respect to the transferring vehicle  91 . 
     The spout end  87  may be adjusted for unloading agricultural material by shifting its spout angle or spout position, within the container perimeter  81  and a tolerance clearance from the container perimeter  81  within the container  85 . The spout end  87  may be adjusted by various techniques that may be applied alternately, or cumulatively. Under a first technique, the alignment module  24  adjusts the spout end  87  for unloading agricultural material by shifting its spout angle (e.g., a first spout angle (α), a second spout angle (β), or both.) Under a second technique, the alignment module  24  requests (or commands) the coordination module  57  to adjust the fore/aft offset adjustment (Φ or φ), the lateral adjustment (Δ), or both, where the coordination module  57  manages or choreographs the relative fore/aft offset and lateral offset between the transferring vehicle  91  and receiving vehicle  79 . Under a third technique, the alignment module  24  primarily adjusts the spout end  87  for unloading agricultural material by shifting its spout angle and the coordination module  57  secondarily and regularly (e.g., periodically) moves the fore/aft offset and the lateral offset by fore/aft offset adjustment (Φ or φ), the lateral adjustment (Δ), respectively, to achieve a uniform fill state or level loading of the container with the agricultural material. Accordingly, the spout end  87  may be adjusted regularly (e.g., in a matrix of one or more rows or columns of preset offset positions) for unloading agricultural material by shifting the spatial relationship between the transferring vehicle  91  and the receiving vehicle  79  by a fore and aft offset or a lateral offset to achieve a target alignment or desired even distribution of filling the container  85  or storage portion  93  with agricultural material, while using the spout angle adjustment for fine tuning of the distribution of the agricultural material within the container (e.g., from each position within the matrix). 
     In the image processing module  18 , the arbiter  25  comprises an image data evaluator. For example, the arbiter  25  may comprise an evaluator, a judging module, Boolean logic circuitry, an electronic module, a software module, or software instructions for determining whether to use the first image data, the second image data, or both for alignment of a relative position of the spout and the container perimeter (or alignment of the spatial offset between the vehicles) based on evaluation of material variation of intensity of pixel data or material variation in ambient light conditions during a sampling time interval. 
     A mode controller  225  is coupled to the data bus (e.g.,  60 ). The mode controller  225  may comprise a perception quality evaluator, a judging module, Boolean logic circuitry, an electronic module, a software module, or software instructions for determining whether to operate the machine-vision-augmented guidance system (e.g.,  11 ,  111 , or  411 ) in: (1) an operator-directed manual mode in which one or more human operators steer the receiving vehicle  79 , the transferring vehicle  91  or both during transfer of agricultural material from the transferring vehicle  91  to the steering vehicle; (2) an automated mode in which the receiving vehicle  79 , the transferring vehicle  91  or both are steered and aligned automatically during transfer of agricultural material from the transferring vehicle  91  to the receiving vehicle  79 ; or (3) a partially automated mode in which one or more operators supervise and can override the automated steering and alignment of the transferring vehicle and the receiving vehicle. For example, the mode controller  225  may determine whether to use an automated control mode of the spout or an operator-directed manual control mode of the spout based on a first operational status of a first location determining receiver  42  associated with the transferring vehicle  91 , a second operational status of a second location determining receiver  142  associated with the receiving vehicle  79 , and a third operational status of the first imaging device. 
     In one embodiment, the mode controller  225  comprises a perception quality evaluator that evaluates the functionality, diagnostics, performance, tests or quality of one or more location determining receivers  42 ,  142 , imaging devices  10 ,  12 , range finders, odometry sensors  440 , dead-reckoning sensors, inertial sensors  442 , navigation sensors, or other perception sensors. In one illustrative example, the first operational status is acceptable if the first location determining receiver  42  provides reliable position data that meets or exceeds a dilution of precision threshold or another navigation satellite reliability measure during a sampling period; the second operational status is acceptable if the second location determining receiver  142  provides reliable position data that meets or exceeds a dilution of precision threshold or another navigation satellite reliability measure (e.g., total equivalent user range error) during a sampling period; and the third operational status is acceptable if the first imaging device  10  provides reliable image data in which the container module  20  or spout module  22  (e.g., or the respective edge detection modules therein) are capable of any of the following: (1) reliably identifying or resolving one or more edges of spout  89  or container perimeter  81  in the collected image data during a sampling time period, or (2) reliably identifying on a time percentage basis (e.g., at least 99.99% of the time) one or more reference objects (e.g., a reference pattern or reference image on the spout or receiving vehicle  79 ) or objects in the image data. 
     Dilution of precision provides a figure of merit of the performance of a location determining receiver  42 ,  142  that uses a satellite navigation system, such as the Global Positioning System (GPS) or Global Navigation Satellite System (GLONASS). Dilution of precision captures the time-varying impact of spatial geometry and separation between a location determining receiver  42 ,  142  and satellites signals that are received by the location determining receiver, as opposed to clock errors, ionospheric errors, multipath errors, and other errors. The precision in pseudo-range estimate to each satellite can affect the accuracy of the determination of a three dimensional position estimate and time estimate of the location determining receiver  42 ,  142 . If receivable navigation satellites are spatially too close together in orbit for a given location determining receiver a particular time, accuracy of the position estimate may be compromised and the dilution of precision value can be higher than normal or acceptable. 
     A master controller  59  is coupled to the data bus  58 ,  60 . In one embodiment, the master controller  59  comprises an auto-guidance module  55  and coordination module  57 . The auto-guidance module  55  or master controller  59  can control the transferring vehicle  91  in accordance with location data from the first location determining receiver  42  and a path plan or desired vehicle path (e.g., stored in data storage  19 ). The auto-guidance module  55  or master controller  59  sends command data to the steering controller  32 , the braking controller  36  and the propulsion controller  40  to control the path of the transferring vehicle to track automatically a path plan or to track manually steered course of an operator via the user interface  44  or steering system  30 . 
     The coordination module  57  may facilitate alignment of movement (e.g., choreography) between the transferring vehicle  91  ( FIG. 4A ) and the receiving vehicle  79  ( FIG. 4A ) during unloading or transferring of agricultural material between the vehicles. For example, the coordination module  57  may facilitate maintenance of a uniform lateral offset (Δ in  FIG. 4 ) and a uniform fore/aft offset (Φ or φ in  FIG. 4 ) between the vehicles during unloading of the agricultural material, subject to any adjustments for attainment of a uniform distribution of material in the container  85 . Collectively, the uniform lateral offset and uniform for/aft offset may be referred to as a uniform spatial offset. In certain embodiments, maintenance of the lateral offset and fore/aft offset, or coordination of any shift in the lateral offset and fore/aft offset (e.g., pursuant to a two-dimensional matrix of pre-established positions (x, y points) for uniform loading of a respective particular container or storage portion), is a necessary or desired precondition to implementing spout angle adjustment of the spout  89  or spout end  87  by the alignment module  24 . 
     In one embodiment in a leader mode, the transferring vehicle  91  is steered by the auto-guidance module  55  or the steering controller  32  in accordance with path plan, or by a human operator. The master controller  59  or coordination module  57  controls the receiving vehicle  79  in a follower mode via the slave controller  159 , where the transferring vehicle  91  operates in the leader mode. If the transferring vehicle  91  operates in an automated mode or auto-steering mode, the master controller  59  provides command data locally to the steering controller  32 , braking controller  36 , and propulsion engine controller  40  of the transferring vehicle  91 . Such command data can be normalized (or scaled), time stamped, and communicated to the receiving vehicle  79  via wireless communication devices  48 ,  148  for processing by the slave controller  159 . Alternatively, the velocity, acceleration, and heading data of the transferring vehicle  91  is communicated to the receiving vehicle  79  via the wireless communications devices  48 ,  148  to enable to receiving vehicle to follow the path of the transferring vehicle  91  (e.g., with a minimal time delay). In an automated mode and in a leader-follower mode, the receiving vehicle  79 , the transferring vehicle or both are steered and aligned automatically during transfer of agricultural material from the transferring vehicle  91  to the receiving vehicle  79 . 
     The image processing module  18  provides image data to a user interface processing module  26  that provides, directly or indirectly, status message data and performance message data to a user interface  44 . As illustrated in  FIG. 1 , the image processing module  18  communicates with a vehicle data bus  31  (e.g., Controller Area Network (CAN) data bus). 
     In one embodiment, a location determining receiver  42 , a first wireless communications device  48 , a vehicle controller  46 , a steering controller  32 , a braking controller  36 , and a propulsion controller  40  are capable of communicating over the vehicle data bus  31 . In turn, the steering controller  32  is coupled to a steering system  30  of the transferring vehicle  91 ; the braking controller  36  is coupled to the braking system  34  of the transferring vehicle  91 ; and the propulsion controller  40  is coupled to the propulsion system  38  of the transferring vehicle  91 . 
     In  FIG. 1 , the steering system  30  may comprise an electrically-driven steering system, an electro-hydraulic steering system, a gear driven steering system, a rack and pinion gear steering system, or another steering system that changes the heading of the vehicle or one or more wheels of the vehicle. The braking system  34  may comprise a regenerative braking system, an electro-hydraulic braking system, a mechanical breaking system, or another braking system capable of stopping the vehicle by hydraulic, mechanical, friction or electrical forces. The propulsion system  38  may comprise one or more of the following: (1) the combination of an electric motor and an electric controller, (2) internal combustion engine that is controlled by an electronic fuel injection system or another fuel metering device that can be controlled by electrical signals, or (3) a hybrid vehicle in which an internal combustion engine drives a electrical generator, which is coupled to one or more electric drive motors. 
     The system  11  facilitates the transfer of agricultural material from the transferring vehicle  91  (e.g., a harvesting vehicle) to a receiving vehicle  79 . The system  11  comprises a receiving vehicle  79  with a propelled portion for propelling the receiving vehicle  79  and a storage portion  93  for storing agricultural material. A stereo imaging device, such as the first imaging device  10 , faces towards the storage portion  93  of the receiving vehicle  79 . As shown in  FIG. 1 , the first imaging device  10  and the optional second imaging device  12  are mounted on the transferring vehicle  79 , consistent with  FIG. 4 . 
     One or more imaging devices  10 ,  12  are arranged to collect image data. A container module  20  identifies a container perimeter  81  of the storage portion  93  in the collected image data. The storage portion  93  has an opening inward from the container perimeter for receipt of the agricultural material. A spout module  22  is configured to identify a spout  89  ( FIG. 4A ) of the transferring vehicle  91  in the collected image data. An alignment module  24  is adapted for determining the relative position of the spout  89  and the container perimeter  81  ( FIG. 4A ) and for generating command data to the transferring vehicle or the propelled portion  75  of the receiving vehicle  79  to steer the storage portion  93  in cooperative alignment such that the spout  89  is aligned within a central zone  83  of the container perimeter  81 . A steering controller  32  is associated with a steering system  30  of the propelled portion for steering the receiving vehicle  79  in accordance with the cooperative alignment. 
     In one embodiment, an optional mast controller  674 , indicated by dashed lines, is coupled to the vehicle data bus  60 , the implement data bus  58  in  FIGS. 1, 2  and  FIG. 3A ), or the image processing module  18  to control an optional adjustable mast  573  for mounting and adjustably positioning the first imaging device  10 , the second imaging device  12 , or both. The mast controller  674  is adapted to change the orientation or height above ground of the first imaging device  10 , the second imaging device  12  or both, where the orientation may be expressed as any of the following: a tilt angle, a pan angle, a down-tilt angle, a depression angle, or a rotation angle. 
     In one illustrative embodiment of a machine-vision guidance system (e.g.,  11 ,  111 ,  311 ) that has an adjustable mast  573 , at least one imaging device  10 ,  12  faces towards the storage portion  93  of the receiving vehicle  79  and collects image data. For example, via data from the mast controller  674  the adjustable mast  573  is capable of adjusting a height of the imaging device  10 ,  12  within a height range, adjusting a down-tilt angle of the imaging device  10 ,  12  within a down-tilt angular range, and a rotational angle or pan angle within a pan angular range. The image processing module  18  is adapted or programmed (e.g., with software instructions or code) to determine whether to adjust the height of the imaging device  10 ,  12  or whether to decrement or increment the down-tilt angle of the imaging device  10 ,  12  based on evaluation of material variation of intensity of pixel data or material variation in ambient light conditions (e.g., from the optical sensor  110 ,  112 ) during a sampling time interval. Under certain operating conditions, such as outdoor ambient light conditions, increasing or incrementing the down-tilt angle may increase the quality level of the collected image data or reduce variation in the intensity of the image data to below a threshold variation level. Reduced variation in intensity of the image data or reduced collection of dust or debris on a lens of the imaging device are some advantages that can be realized by increasing or adjusting down-tilt angle of the imaging device  10 ,  12 , for example. As previously noted, a container module  19  can identify a container perimeter  81  of the storage portion  93  in the collected image data. Similarly, a spout module  22  can identify a spout of the transferring vehicle  91  in the collected image data. An alignment module  24  determines the relative position of the spout and the container perimeter  81  and generates command data to the propelled portion  75  to steer the storage portion  93  in cooperative alignment such that the spout  89 , or spout end  87 , is aligned within a target zone or central zone of the container perimeter  81 . A steering controller  32  is associated with a steering system  30  of the propelled portion  75  for steering the receiving vehicle  79  in accordance with the cooperative alignment. 
     In one illustrative embodiment of a machine-vision guidance system with the adjustable mast  573 , the image processing module  18  sends a data message to a mast controller  674  (or the adjustable mast  573 ) to increment or increase the down-tilt angle if the material variation of intensity of pixel data or if the material variation in ambient light conditions exceeds a threshold variation level during a sampling time interval. For example, the image processing module  18  sends a data message to a mast controller  674  to increment or increase the down-tilt angle at discrete levels (e.g., one degree increments or decrements) within an angular range of approximately negative ten degrees to approximately negative twenty-five degrees from a generally horizontal plane. 
     In one configuration, a user interface  44  is arranged for entering container reference data or dimensional parameters related to the receiving vehicle  79  into vehicle module  1000 . For example, the container reference data or dimensional parameters comprise a distance between a trailer hitch or pivot point (which interconnects the propulsion unit  75  and the storage portion  93 ) and front wheel rotational axis of the storage portion  93  of the receiving vehicle  79 . 
     In an alternate embodiment, in  FIG. 1  and  FIG. 4A  the first imaging device  10  comprises a monocular imaging device and the second imaging device  12  comprises a monocular imaging device that provides first monocular image data and second monocular image data, respectively. The image processing module  18  or system ( 11 ,  111 ) can create a stereo image from the first monocular image data (e.g., right image data) and the second monocular image data (e.g., left image data) with reference to the relative position and orientation of the first imaging device  10  and the second imaging device  12 . The image processing module  18  determines: (1) at least two points on a common visual axis that bisects the lenses of both the first imaging device  10  and the second imaging device  12 , and (2) a linear spatial separation between the first imaging device  10  and the second imaging device  12 , where the first field of view  77  of the first imaging device  10  and the second field of view  177  of the second imaging device  12  overlap, at least partially, to capture the spout  89 , the spout end  87  and the container perimeter  81  in the collected image data. 
     In an alternate embodiment,  FIGS. 1 and 2  further comprises an optional odometer sensor  440 , and an optional inertial sensor  442 , as illustrated by the dashed lines. The odometer sensor  440  may comprise a magnetic rotation sensor, a gear driven sensor, or a contactless sensor for measuring the rotation of one or more wheels of the transferring vehicle  79  to estimate a distance traveled by the transferring vehicle during a measurement time period, or a ground speed of the transferring vehicle  79 . The odometry sensor  440  may be coupled to the vehicle data bus  60  or an implement data bus  58 . The inertial sensor  442  may comprise one or more accelerometers, gyroscopes or other inertial devices coupled to the vehicle data bus  60  or an implement data bus  58 . The optional odometry sensor  440  and the optional inertial sensor  442  may augment or supplement position data or motion data provided by the first location determining receiver  42 . 
     The system  11  of  FIG. 1  is well suited for use on a combine or harvester as the transferring vehicle  91 . The system  11  of  FIG. 1  may communicate and cooperate with a second system  411  on the receiving vehicle  79  (e.g., as illustrated in  FIG. 3B ) to coordinate the relative alignment of the transferring vehicle  91  and the receiving vehicle  79  during unloading or transferring of material from the transferring vehicle  79 . Like reference numbers in  FIG. 1  and  FIG. 2  indicate like elements. 
     The vision-augmented guidance system  111  of  FIG. 2  is similar to the system  11  of  FIG. 1 ; except that the system  111  of  FIG. 2  further comprises an implement data bus  58 , a gateway  29 , and vehicle controllers  50 ,  54  coupled to the vehicle data bus  60  for the lights  14  and spout  89 . The vehicle controller  50  controls the lights  14 ; the spout controller  54  controls the spout  89  via a servo-motor, electric motor, or an electro-hydraulic mechanism for moving or adjusting the orientation or spout angle of the spout  89 , or its spout end  87 . In one configuration, the implement data bus  58  may comprise a Controller Area Network (CAN) implement data bus. Similarly, the vehicle data bus  60  may comprise a controller area network (CAN) data bus. In an alternate embodiment, the implement data bus  58 , the vehicle data bus  60 , or both may comprise an ISO (International Organization for Standardization) data bus or ISOBUS, Ethernet or another data protocol or communications standard. 
     The gateway  29  supports secure or controlled communications between the implement data bus  58  and the vehicle data bus  60 . The gateway  29  comprises a firewall (e.g., hardware or software), a communications router, or another security device that may restrict or prevent a network element or device on the implement data bus  58  from communicating (e.g., unauthorized communication) with the vehicle data bus  60  or a network element or device on the vehicle data bus  31 , unless the network element or device on the implement data bus  58  follows a certain security protocol, handshake, password and key, or another security measure. Further, in one embodiment, the gateway  29  may encrypt communications to the vehicle data bus  60  and decrypt communications from the vehicle data bus  60  if a proper encryption key is entered, or if other security measures are satisfied. The gateway  29  may allow network devices on the implement data bus  58  that communicate via an open standard or third party hardware and software suppliers, whereas the network devices on the vehicle data bus  60  are solely provided by the manufacturer of the transferring vehicle (e.g., self-propelled forage harvester) or those authorized by the manufacturer. 
     In  FIG. 2 , a first location determining receiver  42 , a user interface  44 , a user interface processing module  26 , and the gateway  29  are coupled to the implement data bus  58 , although in other embodiments such elements or network devices may be connected to the vehicle data bus  60 . controllers  50 ,  54  are coupled to the vehicle data bus  60 . In turn, the controllers  50 ,  54  are coupled, directly or indirectly, to lights  14  on the transferring vehicle  91  and the spout  89  of the transferring vehicle  91  (e.g., self-propelled forage harvester). Although the system of  FIG. 2  is well suited for use or installation on a self-propelled forage harvester, the system of  FIG. 2  may also be applied to combines, harvesters or other heavy equipment. 
     The system  11  of  FIG. 1  and the system  111  of  FIG. 2  apply to the transferring vehicle  91 , whereas the system of  FIGS. 3A and 3B  applies to the receiving vehicle  79 . Like reference numbers in  FIGS. 1, 2, 3A, and 3B  indicate like elements. As previously noted, the transferring vehicle  91  may comprise a combine, harvester, self-propelled harvester, vehicle or heavy equipment that collects or harvests material for transfer to the receiving vehicle  79 . In one embodiment, the receiving vehicle  79  may comprise a propelled portion  75  ( FIGS. 4A and 5A ) and a storage portion  93  ( FIGS. 4A and 5A ) for storing the material transferred from the transferring vehicle  91 . The receiving vehicle  79  may comprise the combination of a tractor and a grain cart or wagon, where the tractor is an illustrative example of the propelled portion  75  and where the grain cart is an illustrative example of the storage portion  93 . 
     In one embodiment of  FIG. 5D , both the transferring vehicle  91  and the receiving vehicle  79  may be moving forward at approximately the same velocity and heading (e.g., within a tolerance or error of the control systems during harvesting), where the relative position of the receiving vehicle  79  is generally fixed or constant with respect to each position ( 502 ,  504 ) in the matrix  500  that the transferring vehicle  91  can occupy. 
     In an alternate embodiment, the receiving vehicle  79  may be shown as occupying a two dimensional matrix (e.g., 3×3 matrix, with three columns and three rows) of possible offset positions, while the position of the transferring vehicle  91  is generally fixed or constant with respect to each position of matrix that the receiving vehicle  79  could occupy. As directed by any of the systems ( 11 ,  111 ,  311 ) in the alternate embodiment, the imaging processing module  18 , or the master controller  159  of the receiving vehicle  79  can shift to any unoccupied or other possible offset positions within the matrix to promote or facilitate an even distribution of agricultural material within the container  85  or storage portion of the receiving vehicle  79 . 
     In  FIG. 6  and  FIG. 7 , each of the blocks or modules may represent software modules, electronic modules, or both. Software modules may contain software instructions, subroutines, object-oriented code, or other software content. The arrows that interconnect the blocks or modules of  FIG. 6  show the flow of data or information between the blocks. The arrows may represent physical communication paths or virtual communication paths, or both. Physical communication paths mean transmission lines or one or more data buses for transmitting, receiving or communicating data. Virtual communication paths mean communication of data, software or data messages between modules. 
       FIG. 6  is a block diagram that shows the imaging processing module  18  and the container module  20  in greater detail than  FIG. 1 . Like reference numbers in  FIG. 1 ,  FIG. 6 , and  FIG. 7  indicate like elements. As illustrated in  FIG. 6 , the first imaging device  10 , the second imaging device  12 , or both, provide input of raw stereo camera images (or raw image data) to the image rectification module  101 . In turn, the image rectification module  101  communicates with the disparity image generator  103  and the edge detector  105 . The edge detector  105  provides an output to the linear Hough transformer  107 . The outputs of the disparity image generator  103  and the linear Hough transformer  107  are provided to the container localizer  111 . The container localizer  111  may access or receive stored (a priori) hitch and container measurements, container dimensions, container volume or other receiving vehicle data from the data manager  109 . In one embodiment, the container localizer  111  may receive or access and an estimate of the tongue angle (between the propulsion portion  75  and the storage portion  93  of the receiving vehicle  79 ) from the angle estimator  113  (e.g., Kalman filter) and stored hitch and container measurements. 
     In the another embodiment, the image rectification module  101  provides image processing to the collected image data or raw stereo images to reduce or remove radial lens distortion and image alignment required for stereo correspondence. The radial lens distortion is associated with the radial lenses of the first imaging device  10 , the second imaging device  12 , or both. The input of the image rectification module  101  is raw stereo image data, whereas the output of the image rectification module  101  is rectified stereo image data. 
     In one illustrative embodiment, the image rectification module  101  eliminates or reduces any vertical offset or differential between a pair of stereo images of the same scene of the image data. Further, the image rectification module  101  can align the horizontal component (or horizontal lines of pixels of the stereo images) to be parallel to the scan lines or common reference axis of each imaging device (e.g., left and right imaging device) within the first and second imaging devices  10 ,  12 . For example, the image rectification module may use histogram equalization and calibration information for the image processing devices  10 ,  12  to achieve rectified right and left images of the stereo image. The rectified image supports efficient processing and ready identification of corresponding pixels or objects within the image in the left image and right image of a common scene for subsequent image processing (e.g., by the disparity image generator  103 ). 
     In one configuration, the disparity image generator  103  applies a stereo matching algorithm or disparity calculator to collected stereo image data, such as the rectified stereo image data outputted by the image rectification module  101 . The stereo matching algorithm or disparity calculator may comprise a sum of absolute differences algorithm, a sum of squared differences algorithm, a consensus algorithm, or another algorithm to determine the difference or disparity for each set of corresponding pixels in the right and left image (e.g., along a horizontal axis of the images or parallel thereto). 
     In an illustrative sum of the absolute differences procedure, the right and left images (or blocks of image data or rows in image data) can be shifted to align corresponding pixels in the right and left image. The stereo matching algorithm or disparity calculator determines a disparity value between corresponding pixels in the left and right images of the image data. For instance, to estimate the disparity value, each first pixel intensity value of a first subject pixel and a first sum of the first surrounding pixel intensity values (e.g., in a block or matrix of pixels) around the first pixel is compared to each corresponding second pixel intensity value of second subject pixel and a second sum of the second surrounding pixel intensity values (e.g., in a block or matrix of pixels) around the second pixel. The disparity values can be used to form a disparity map or image for the corresponding right and left image data. 
     The image processing module  18 , or container localizer  111 , estimate a distance or range from the first imaging device  10 , the second imaging device  12 , or both to the pixels or points lying on the container perimeter  81 , on the container edge  181 , on the spout  89 , on the spout end  87 , or on any other linear edge, curve, ellipse, circle or object identified by the edge detector  105 , the linear Hough transformer  107 , or both. For example, the image processing module  18  may use the disparity map or image to estimate a distance or range from the first imaging device  10 , the second imaging device  12 , or both to the pixels or points lying on the container perimeter  81 , the container edges  181 , the container opening  83 , in the vicinity of any of the foregoing items, or elsewhere. 
     In one embodiment, the container module  20  comprises: (1) an edge detector  105  for measuring the strength or reliability of one or more edges  181 , or points on the container perimeter  81  in the image data; (2) a linear Hough transformer  107  for identifying an angle and offset of candidate linear segments in the image data with respect to a reference point on an optical axis, reference axis of the one or more imaging devices  10 ,  12 ; (3) a container localizer  111  adapted to use spatial and angular constraints to eliminate candidate linear segments that cannot logically or possibly form part of the identified linear segments of the container perimeter  81 , or points on the container perimeter  81 ; and (4) the container localizer  111  transforms the non-eliminated, identified linear segments, or identified points, into two or three dimensional coordinates relative to a reference point or reference frame of the receiving vehicle and harvesting vehicle. 
     The edge detector  105  may apply an edge detection algorithm to rectified image data from the image rectification module  101 . Any number of suitable edge detection algorithms can be used by the edge detector  105 . Edge detection refers to the process of identifying and locating discontinuities between pixels in an image or collected image data. For example, the discontinuities may represent material changes in pixel intensity or pixel color which defines boundaries of objects in an image. A gradient technique of edge detection may be implemented by filtering image data to return different pixel values in first regions of greater discontinuities or gradients than in second regions with lesser discontinuities or gradients. For example, the gradient technique detects the edges of an object by estimating the maximum and minimum of the first derivative of the pixel intensity of the image data. The Laplacian technique detects the edges of an object in an image by searching for zero crossings in the second derivative of the pixel intensity image. Further examples of suitable edge detection algorithms include, but are not limited to, Roberts, Sobel, and Canny, as are known to those of ordinary skill in the art. The edge detector  105  may provide a numerical output, signal output, or symbol, indicative of the strength or reliability of the edges  181  in field. For example, the edge detector may provide a numerical value or edge strength indicator within a range or scale or relative strength or reliability to the linear Hough transformer  107 . 
     The linear Hough transformer  107  receives edge data (e.g., an edge strength indicator) related to the receiving vehicle and identifies the estimated angle and offset of the strong line segments, curved segments or generally linear edges (e.g., of the container  85 , the spout  89 , the spout end  87  and opening  83 ) in the image data. The estimated angle is associated with the angle or compound angle (e.g., multidimensional angle) from a linear axis that intercepts the lenses of the first imaging device  10 , the second image device  12 , or both. The linear Hough transformer  107  comprises a feature extractor for identifying line segments of objects with certain shapes from the image data. For example, the linear Hough transformer  107  identifies line equation parameters or ellipse equation parameters of objects in the image data from the edge data outputted by the edge detector  105 , or Hough transformer  107  classifies the edge data as a line segment, an ellipse, or a circle. Thus, it is possible to detect containers or spouts with generally linear, rectangular, elliptical or circular features. 
     In one embodiment, the data manager  109  supports entry or selection of container reference data by the user interface  44 . The data manager  109  supports entry, retrieval, and storage of container reference data, such as measurements of cart dimensions, by the image processing module  18  to give spatial constraints to the container localizer  111  on the line segments or data points that are potential edges  181  of the cart opening  83 . 
     In one embodiment, the angle estimator  113  may comprise a Kalman filter or an extended Kalman filter. The angle estimator  113  estimates the angle of the storage portion  93  (e.g., cart) of the receiving vehicle  79  to the axis of the direction of travel of the propelled portion  75  (e.g., tractor) of the receiving vehicle  79 . The angle estimator  113  (e.g., Kalman filter) provides angular constraints to the container localizer  111  on the lines, or data points, that are potential edges  181  of the container opening  83 . In configuration, the angle estimator  113  or Kalman filter is coupled to the localizer  111  (e.g., container localizer). The angle estimator filter  113  outputs, or is capable of providing, the received estimated angle of the storage portion  93  relative to the axis of the direction of travel of the propelling portion  75  of the vehicle. 
     The localizer  111  is adapted to receive measurements of dimensions of the container perimeter  81  or the storage portion  93  of the vehicle to facilitate identification of candidate linear segments that qualify as identified linear segments of the container perimeter  81 . In one embodiment, the localizer  111  is adapted to receive an estimated angle of the storage portion  93  relative to the propelling portion  75  of the vehicle to facilitate identification of candidate linear segments that qualify as identified linear segments of the container perimeter  81 . The localizer  111  uses spatial and angular constraints to eliminate candidate lines in the image data that cannot be possibly or logically part of the container opening  83  or container edges  181 , then selects preferential lines (or data points on the container edge  81 ) as the most likely candidates for valid container opening  83  (material therein) or container edges  181 . The localizer  111  characterizes the preferential lines as, or transformed them into, three dimensional coordinates relative to the vehicle or another frame of reference to represent a container perimeter of the container  85 . 
       FIG. 7  is a block diagram that shows the image processing module  18  and the spout module  22  in greater detail than  FIG. 1 . Like reference numbers in  FIGS. 1, 2, 3A, 3B, 6 and 7  indicate like elements. In  FIG. 7 , the image rectification module  101  communicates with the disparity image generator  103  and the spout classifier  121 . In turn, the spout classifier  121  provides an output to the spout localizer  125 . The spout localizer  125  accesses or receives the spout position from angle sensor  115  or the spout position estimator  123  (or spout angle (α) with respect to the transferring vehicle direction of travel or vehicle reference frame), stereo correspondence data from the disparity image generator  103 , and the output data from the spout classifier  121 . 
     In one embodiment, the spout (identification) module  22  comprises a spout classifier  121  that is configured to identify candidate pixels in the image data based at least one of reflectivity, intensity, color or texture features of the image data (or pixels), of the rectified image data or raw image data, where the candidate pixels represent a portion of the spout  89  or spout end  87 . The spout localizer  125  is adapted to estimate a relative position of the spout  89  to the imaging device based on the classified, identified candidate pixels of a portion of the spout  89 . The spout localizer  125  receives an estimated combine spout position or spout angle (α) relative to the mounting location of the imaging device, or optical axis, or reference axis of one or more imaging devices, based on previous measurements to provide constraint data on where the spout  89  can be located possibly. 
     The spout classifier  121  applies or includes software instructions on an algorithm that identifies candidate pixels that are likely part of the spout  89  or spout end  87  based on expected color and texture features within the processed or raw image data. For example, in one configuration the spout end  87  may be painted, coated, labeled or marked with a coating or pattern of greater optical or infra-red reflectivity, intensity, or luminance than a remaining portion of the spout  89  or the transferring vehicle. The greater luminance, intensity or reflectivity of the spout end  87  (or associated spout pixels of the image data versus background pixels) may be attained by painting or coating the spout end  87  with white, yellow, chrome or a lighter hue or shade with respect to the remainder of the spout  89  or portions of the transferring vehicle (within the field of view of the imaging devices  10 ,  12 . 
     In one embodiment, the spout position estimator  123  comprises a Kalman filter or an extended Kalman filter that receives input of previous measurements and container reference data and outputs an estimate of the spout position, spout angle, or its associated error. The spout position estimator  123  provides an estimate of the combine spout position, or spout angle, or its error, relative to one or more of the following: (1) the mounting location or pivot point of the spout on the transferring vehicle, or (2) the optical axis or other reference axis or point of the first imaging device  10 , the second imaging device  12 , or both, or (3) the axis associated with the forward direction of travel or the heading of the transferring vehicle. The Kalman filter outputs constraints on where the spout  89  or spout end  87  can be located, an estimated spout position, or a spout location zone or estimated spout position zone. In one embodiment, the spout position estimator  123  or Kalman filter is coupled to the spout localizer  125 . 
     The spout localizer  125  takes pixels that are classified as belonging to the combine auger spout  89  and uses a disparity image (from stereo correspondence data) to estimate the relative location of the spout to the first imaging device  10 , the second imaging device  12 , or both, or reference axis or coordinate system associated with the vehicle. 
     The flow chart of  FIG. 8  begins in block S 800 . In block S 800 , the process starts. In block S 802 , the mode controller  225  or system ( 11 ,  111 ,  311 ) decides if the second location determining receiver  142  of the receiving vehicle provides reliable position data during an evaluation time period. In block S 802 , the determination of reliable position data or acceptable position data may be carried out by the following techniques that may be applied separately or cumulatively. Under a first technique of executing step S 802 , the second location determining receiver  142  provides reliable position data or acceptable position data if the dilution of precision or total equivalent user range error is less than a threshold level during a sampling period. 
     Under a second technique of executing step S 802 , the location determining receiver  142  is assumed to provide reliable position data or acceptable position data, unless the receiver provides an error code, a diagnostic code, a fault code, or an alarm. 
     Under a third technique, the second location determining receiver  142  provides reliable position data or acceptable position data, unless it fails to output location data on a certain monitored data port, or fails to provide accurate or reliable location data on a certain monitored data port consistent with alignment with a known position landmark or reference position in a work area or field. Under the third technique, the transferring vehicle, receiving vehicle or both are aligned with the known position landmark or reference position on a regular or periodic basis (e.g., at start of harvesting or at the beginning of an agricultural task) to check for reliable performance of the location determining receivers ( 42 ,  142 ). 
     If the second location determining receiver  142  provides reliable position data during the evaluation time period, the method continues with block S 806 . However, if the second location determining receiver  142  does not provide reliable position data during the evaluation time period, then the method continues with block S 804 . 
     In block S 804 , the image processing module  18 , the arbiter  25 , the mode controller  225 , or the system ( 11 ,  111 ,  311 ) decides if at least one imaging device (e.g.,  10 ,  12 , stereo vision imaging device or a pair of monocular imaging devices) is providing reliable image data. In one example, the imaging device provides reliable or acceptable image data in which the container module  20  or spout module  22  (e.g., or the respective edge detection modules therein) are capable of one or more of the following: (1) reliably identifying or resolving one or more edges of spout  89  or container perimeter  81  in the collected image data during a sampling time period, or (2) reliably identifying on a time percentage basis (e.g., at least 99.99% of the time) one or more reference objects (e.g., a reference pattern or reference image on the spout or receiving vehicle) or objects in the image data. If the imaging device ( 10 ,  12 ) is providing reliable image data, then the method continues with block S 812 . However, if the imaging device ( 10 ,  12 ) is not providing reliable image data, then the method continues with block S 808 . 
     In block S 806 , the mode controller  225  or the system ( 11 ,  111 ,  311 ) decides if the first location determining receiver  42  of the transferring vehicle is providing reliable position data. In block S 806 , the determination of reliable position data or acceptable position data may be carried out by the following techniques that may be applied separately or cumulatively. Under a first technique of executing step S 802 , the first location determining receiver  42  provides reliable position data or acceptable position data if the dilution of precision or total equivalent user range error is less than a threshold level during a sampling period. 
     Under a second technique of executing step S 802 , the first location determining receiver  42  is assumed to provide reliable position data or acceptable position data, unless the receiver provides an error code, a diagnostic code, a fault code, or an alarm. 
     Under a third technique, the first location determining receiver  42  provides reliable position data or acceptable position data, unless it fails to output location data on a certain monitored data port, or fails to provide accurate or reliable location data on a certain monitored data port consistent with alignment with a known position landmark or reference position in a work area or field. Under the third technique, the transferring vehicle, receiving vehicle or both are aligned with the known position landmark or reference position on a regular or periodic basis (e.g., at start of harvesting or at the beginning of an agricultural task) to check for reliable performance of the location determining receivers ( 42 ,  142 ). 
     If the first location determining receiver  42  of the transferring vehicle is providing reliable position data, the method continues with step S 810 . However, if the first location-determining receiver  42  is not providing reliable position data, the method continues with or returns to block S 804 . 
     In block S 808 , the image processing module  18 , the arbiter  25 , or the mode controller  225  determines that the system ( 11 ,  111 ,  311 ) does not provide reliable tracking data for automated guidance and alignment of the spout  89  and the container  85  of the receiving portion  93 . Accordingly, the image processing system  18 , arbiter  25 , or mode controller  225  determines that the system ( 11 ,  111 ,  311 ) shall operate in an operator-directed manual mode for a control time period following the evaluation time period. 
     In block S 810 , the image processing module  18 , the arbiter  25 , or the mode controller  225  decides if at least one imaging device (e.g.,  10 ,  12 , stereo vision imaging device or a pair of monocular imaging devices) is providing reliable image data. In one example, the imaging device ( 10 ,  12 ) provides reliable or acceptable image data in which the container module  20  or spout module  22  (e.g., or the respective edge detection modules therein) are capable of any of the following: (1) reliably identifying or resolving one or more edges of spout  89  or container perimeter  81  in the collected image data during a sampling time period, or (2) reliably identifying on a time percentage basis (e.g., at least 99.99% of the time) one or more reference objects (e.g., a reference pattern or reference image on the spout  89  or receiving vehicle  91 ) or objects in the image data. 
     If the imaging device ( 10 ,  12 ) is providing reliable image data, then the method continues with block S 814 . However, if the imaging device is not providing reliable image data, then the method continues with block S 816 . 
     In block S 812 , the image processing module  18 , mode controller  225 , or system ( 11 ,  111 ,  311 ) operates in the manual mode or a partially automated mode. In the partially automated mode, an operator may be present in the vehicles for overriding, supplementing or correcting the guidance or alignment data providing by the imaging device ( 10 ,  12 ) tracking, the odometry data (via odometry sensor  440 ), inertial data (via inertial sensor  442 ) and the angle estimator  113 . For example, in step S 812  the imaging processing module  18  or mode controller  225  uses camera tracking, odometry data, and the angle estimator  113  (e.g., Kalman filter). The angle estimator  113  can be used to estimate an angle between a propulsion unit and a container of the receiving vehicle. 
     In block S 814 , the image processing module  18 , mode controller  225 , or system ( 11 ,  111 ,  311 ) operates in the automated mode. For example, the imaging processing module  18  or mode controller  225  uses position data of the location determining receivers ( 42 ,  142 ), tracking data of at least one imaging device ( 10 ,  12 ), and the angle estimator  113  (e.g., Kalman filter). The angle estimator  113  can be used to estimate an angle between a propulsion portion  75  and a storage portion  93  of the receiving vehicle. 
     In block S 816 , the imaging processing module  18 , mode controller  225 , or system operates in a manual mode or partially automated mode. In the partially automated mode, one or more operators may be present in the vehicles ( 79 ,  91 ) for overriding, supplementing or correcting the guidance or alignment data providing by the location determining receivers ( 42 ,  142 ). For example, the imaging processing module  18  uses position data of the location determining receivers ( 42 ,  142 ) to guide the vehicles or to align the spout and the container. 
     After block S 808 , S 812 , S 814  or S 816 , the method of  FIG. 8  may continue with block S 817 . In block S 817 , the image processing module  18 , mode controller  225 , or system may wait a time period (e.g., a control time period or an evaluation time period) prior to looping or returning to step S 802 . 
       FIG. 9  is a flow chart of a method for facilitating the unloading of agricultural material from a vehicle or between a transferring vehicle  91  and a receiving vehicle  79 . The method of  FIG. 9  begins in step S 900  and may use one or more of the following embodiments of the systems  11 ,  111 , or  311  previously disclosed herein. 
     In step S 900 , the transferring vehicle  91  (e.g., harvester or combine) stores agricultural material in a storage portion (e.g., grain bin) of the transferring vehicle  91 . For example, the transferring vehicle may store the agricultural material in the storage portion of the transferring vehicle  91  as the transferring vehicle  91  moves forward and harvests crop in a field. As the storage portion or storage vessel (e.g., grain tank) of the transferring vehicle  91  becomes full or near capacity, the receiving vehicle may move along one side of the moving transferring vehicle  91  for unloading of the agricultural material (e.g., consistent with or similar to the illustration of  FIGS. 4A and 5A ). 
     In step S 902 , the first imaging device  10  faces toward the storage portion of the receiving vehicle  79  (e.g., grain cart) and collects first image data (e.g., first stereo image data, first monocular image data, or a right image of a stereo image). For example, the first imaging device  10  may be mounted on the transferring vehicle  91  facing the receiving vehicle  79  facing the container  85 . In one embodiment, the first imaging device  10  has first field of view ( 77  in  FIG. 4A ) of the storage portion of the receiving vehicle  79 . 
     In an alternative embodiment, the first imaging device  10  comprises a monocular imaging device that provides a first image section (e.g., left image) of stereo image data of a scene or an object. 
     In step S 904 , where present, the optional second imaging device  12  faces toward the storage portion  93  of the receiving vehicle  79  (e.g., grain cart) and collects second image data (e.g., second stereo image data, second monocular image data, or a left image of a stereo image). For example, the second imaging device  12  may be mounted on the transferring vehicle  91  facing the receiving vehicle  79  (e.g., in  FIG. 4 ) or the receiving vehicle  79  facing the container  85  ( FIG. 5A ). In one embodiment, the second imaging device  12  has a second field of view  177 , of the storage portion of the receiving vehicle, where the first field of view  77  overlaps at least partially with the second field of view  177 . 
     In an alternate embodiment, the second imaging device  12  comprises a monocular imaging device that provides a second image section (e.g., right image) of stereo image data of a scene or an object, where the image processing module  18  supports the creation of a stereo image from a combination of the first image section (of the first monocular imaging device) and the second image section with reference to the relative position and orientation of the first imaging device  10  and the second imaging device  12 . 
     In step S 975 , the operational status of the first imaging device is determined. If the operational status is not acceptable, then odometry and accelerometer data is used for general alignment of the vehicles (step S 978 ). If the operational status is acceptable, then the operational status of the second imaging device is determined (step S 976 ). Thereafter, the operational status of the image processing module is determined (step S 977 ). If the operational status of the image processing module is not acceptable, then the system is authorized to operate in a manual control mode or semi-automated control mode to facilitate general alignment of the vehicles or determination of the relative position of the spout and the storage portion (step S 980 ). If the operational status of the image processing module is acceptable, then the system is authorized to operate in automated control mode where the image processing module processes image data to facilitate determination of the relative position of the spout and the storage portion (step S 979 ). 
     In step S 906 , an image processing module  18  or a container module  20  identifies a container perimeter  81  of the storage portion  93  in the collected image data (e.g., the first image data, the second image data or both), where the storage portion  93  has an opening  83  inward from the container perimeter  81  for receipt of the agricultural material. Step S 106  may be carried out in accordance with various techniques, which may be applied alternately or cumulatively. Under a first technique, the image processing module  18  or container module  20  may employ the following processes or sub-steps: (1) measuring a strength of one or more edges  181  in the image data (raw and rectified image data); (2) identifying an angle and offset of candidate linear segments in the image data with respect to an optical axis, reference axis (e.g., direction of travel of the transferring vehicle), or reference point indexed to one or more imaging devices  10 ,  12 ; and (3) using spatial and angular constraints to eliminate identified candidate linear segments that cannot logically or possibly form part of the identified linear segments of the container perimeter, where the localizer  111  transforms the identified linear segments into three dimensional coordinates relative to a reference point or reference frame of the receiving vehicle and/or the harvesting vehicle. 
     Under a second technique, the image processing module  18  or container module  20  may receive container reference data, or measurements of dimensions of the container perimeter  81  or the storage portion  93  of the vehicle, to facilitate identification of candidate linear segments, or candidate data points, that qualify as identified linear segments of the container perimeter  81 . 
     Under the third technique, the image processing module  18  or container module  20  may receive an estimated angle  97  of the storage portion  93  relative to the propelling portion  75  of the vehicle to facilitate identification of candidate linear segments that qualify as identified linear segments of the container perimeter  81 . 
     Under a fourth technique, the image processing module  18  or container module  20  provides the received estimated angle  97  of the storage portion  93  relative to the propelling portion  75  of the vehicle. 
     In step S 908 , the image processing module  18  or a spout module  22  identifies a spout  89  (or spout end  87 ) of the transferring vehicle (e.g., harvesting vehicle) in the collected image data. The image processing module  18  or the spout module  22  may use various techniques, which may be applied alternately or cumulatively. Under a first technique, the image processing module  18  or the spout module  22  identifies candidate pixels in the image data (e.g., rectified or raw image data) based on expected color and expected texture features of the image data, where the candidate pixels represent a portion of the spout  89  (e.g., combine auger spout) or spout end  87 . 
     Under a second technique, the image processing module  18  or the spout module  22  estimates a relative position, or relative angle, of the spout  89  or the spout end  87 , to the imaging device based on the classified, identified candidate pixels of a portion of the spout  89 . 
     Under a third technique, the image processing module  18  or the spout module  22  receives an estimated combine spout position, or spout angle, relative to the mounting location, optical axis, reference axis, or reference point of the imaging device ( 10 ,  12 ) based on previous measurements to provide constraint data on where the spout  56  can be located possibly. 
     Under a fourth technique, the image processing module  18  or spout module  22  provides the estimated combine spout position, or estimated spout angle, to the spout localizer  125 . 
       FIG. 10  is a flow chart of a method for facilitating the unloading of agricultural material from a vehicle or between a transferring vehicle ( 91 ) and a receiving vehicle ( 79 ). The method of  FIG. 9  begins in step S 900  and may use one or more of the following embodiments of the systems ( 11 ,  111 , or  311 ) previously disclosed herein. 
     The method of  FIG. 10  is similar to the method of  FIG. 9 , except the method of  FIG. 10  replaces step S 981  with step S 911 , as well as eliminated S 975 , S 976 , S 977 , S 978 , S 979 , and S 980 . Like reference numbers in  FIG. 9  and  FIG. 10  indicate like elements. 
     In step S 911 , the mode controller  225  or image processing module  18  determines whether to use an automated control mode of the spout or an operator-directed manual control mode of the spout  89  based on the acceptability or reliability of a first operational status of a first location-determining receiver  42 , a second operational status of a second location-determining receiver  142 , and a third operational status of the imaging device or devices ( 10 ,  12 ). 
     In one illustrative example, the first operational status is acceptable if the first location determining receiver  42  provides reliable position data that meets or exceeds a dilution of precision threshold or another navigation satellite reliability measure during a sampling period; the second operational status is acceptable if the second location determining receiver  142  provides reliable position data that meets or exceeds a dilution of precision threshold or another navigation satellite reliability measure (e.g., total equivalent user range error) during a sampling period; and the third operational status is acceptable if the first imaging device  10  provides reliable image data in which the container module  20  or spout module  22  (e.g., or the respective edge detection modules therein) are capable of any of the following: (1) reliably identifying or resolving one or more edges of spout or container perimeter  81  in the collected image data during a sampling time period, or (2) reliably identifying on a time percentage basis (e.g., at least 99.99% of the time) one or more reference objects (e.g., a reference pattern or reference image on the spout or receiving vehicle) or objects in the image data. 
     Step S 911  may be executed in accordance with one or more procedures that may be applied separately or cumulatively. Under a first procedure, if the first, second and third operational statuses are not acceptable or reliable, the system ( 11 ,  111 ,  311 ) or mode controller  225  reverts to manual mode control for control of the spout  89  and container  85  alignment and the spatial alignment of the transferring vehicle  91  and the receiving vehicle  79  during unloading of agricultural material from the transferring vehicle  91  to the receiving vehicle  79 . 
     Under a second procedure, if the first operational status, the second operational status and the third operational status are acceptable or indicative of properly functioning, the system ( 11 ,  111 ,  311 ) is capable of operating in an automated mode (e.g., fully automated mode) and the mode controller  225  permits the use of the first location determining receiver  42 , the second location determining receiver  142  and the imaging device  10  for one or more of the following: (1) to track or align relative position of the receiving vehicle  79  and the transferring vehicle  91  for control of the spout  89  and container  85  spatial alignment during unloading, and (2) to track or align the spatial alignment of the transferring vehicle  91  and the receiving vehicle  79  during unloading of agricultural material from the transferring vehicle  91  to the receiving vehicle  79 . 
     Under a third procedure, if the first operational status, the second operational status and the third operational status are acceptable or indicative of properly functioning, the system ( 11 ,  111 ,  311 ) or mode controller  225  is capable of operating in an automated mode (e.g., fully automated mode) and determines if there is a storage portion  93  or container  85  (e.g., cart) properly positioned beneath the spout end  87  of the spout  89  so that no material (e.g., grain) will be spilled when the material begins to flow from the spout end  87  to the receiving vehicle. In the automated control mode, if a storage portion  93  is detected and properly positioned with respect to the transferring vehicle  91  and the spout  89 , the system ( 11 ,  111 ,  311 ), imaging module  18  or vehicle controller  46  commands the combine to turn on the unloading auger or auger drive  47 . 
     Under a fourth procedure, if the first operational status and the second operation status are acceptable and if the third operational status is unacceptable, the mode controller  225  permits the use of the first location determining receiver  42  and the second location determining receiver  142  to track or align the relative position of the receiving vehicle  79  and the transferring vehicle  91  during unloading. However, the mode controller  225  may prohibit use of the imaging device ( 10 ,  12 ) to track or align the relative align relative position of the receiving vehicle  79  and the transferring vehicle  91  for control of the spout  89  and container  85  spatial alignment during unloading. Accordingly, where operating under the fourth procedure, the mode may be referred to as partially automated or partially manual mode because automated aspect is limited to the first location determining receiver  42  and the second location determining receiver  142  to track or align the relative position of the receiving vehicle  79  and the transferring vehicle  91  during unloading, subject to manual adjustment of the operator of the transferring vehicle  91  within certain tolerance to align manually the spout  89  and the container  85  of the receiving vehicle  79  for unloading. The tolerance is limited to a spatial separation to prevent or minimize the risk of collision between the transferring vehicle  91  and the receiving vehicle  79  based on the respective dimensions, wheel base, turning radius, speeds, velocities and headings of the transferring vehicle  91  and the receiving vehicle  79 . 
     Under the fifth procedure, the mode controller  225  permits (e.g., temporarily permits) the image processing system ( 11 ,  111 ,  311 ), the mode controller  225  and the steering controller  32  to use collected image data from the first imaging device  10 , odometry data from the odometry sensor  440 , and inertial data from the inertial sensor  442  if the first operational status and the second operational status are unacceptable and if the third operational status is acceptable. Accordingly, under the fifth procedure the mode controller  225  authorizes the system ( 11 ,  111 ,  311 ) to operate in an automated mode (for a limited time period measured from a last available position data from one or more location determining receivers) or a partially automated mode in which the user can override or adjust the spatial separation between the transferring vehicle  91  and the receiving vehicle  79  or the spatial alignment between the spout  89  and the container  85  of the receiving vehicle  79 . For example, the steering controller  32  operates the system ( 11 ,  111 ,  311 ) in a partially automated mode in which an operator supervises the steering system  30  of the transferring vehicle  91  and the receiving vehicle  79 ; where the operator can override the automated steering control of the steering controller  32  by the master controller  59  based on the odometry data and inertial data; after the limited time period expires, the mode controller  225  only authorizes operation in the manual mode, unless the first operational status and the second operational status become acceptable or reliable prior to expiration of the limited time period. 
     Under a sixth procedure, the storage portion  93  of the receiving vehicle  79  begins to become full, the system ( 11 ,  111 ,  311 ), propulsion controller  40 , braking controller  36 , vehicle controller  46 , and auger rotation system  16  may use the profile of the surface the agricultural material to execute the operator-selected fill strategy (e.g., back-to-front, front-to-back, or another fill strategy). 
     To execute the fill strategy in the automated control mode, the system ( 11 ,  111 ,  311 ) can unload the agricultural material into particular areas of the container  85  that contain less agricultural material to promote even filling and distribution of agricultural material in the container  85 . In the automated control mode, the system ( 11 ,  111 ,  311 ) can adjust the unloading alignment between the transferring vehicle  91  and the receiving vehicle  79  by one or more of the following procedures: (1) command the spout  89  to rotate or change its spout angle with respect to the transferring vehicle  91  or a vertical plane associated with the transferring vehicle  91  that intercepts at least one rotational axis of the spout  89 ; (2) command the unloading auger or auger drive  47  to rotate to move agricultural material from the storage in the transferring vehicle to the storage portion  93  of the receiving vehicle; (3) command changes to ground speed, velocity, acceleration or heading of the transferring vehicle  91 , the receiving vehicle  79 , or both; (4) command the operator of the vehicle or vehicles ( 79 ,  91 ) to manually adjust ground speed, velocity, acceleration or heading of the transferring vehicle  91 , the receiving vehicle  79 , or both, or (5) command one or more controllers ( 32 ,  36 ,  38 ) to command the transferring vehicle  91 , the receiving vehicle  79  or both to change its or their relative position. When the entire container  85  or storage portion  93  is filled to capacity or the level selected by the operator, the vehicle controller  46  or auger rotation system  16  turns off the unloading auger or the auger drive  47 . 
     Under a seventh procedure in a manual control mode, the operator interacts with the user interface  44  of the system ( 11 ,  111 ,  311 ) to adjust the unloading alignment between the transferring vehicle and the receiving vehicle by any of the following: (1) the operator&#39;s changing ground speed, velocity, acceleration or heading of the transferring vehicle  91 , the receiving vehicle  79 , or both, or (2) the operator can adjust manually the spout angle based on imaged displayed to an operator on the user interface  44  from an imaging device ( 10 ,  12 ). Further, in the manual control mode, the operator may turn or off the unloading auger or auger drive. 
     The method of  FIG. 11  is similar to the method of  FIG. 9 , except the method of  FIG. 11  further comprises step S 916  and S 918 . Like reference numbers in  FIG. 9  and  FIG. 11  indicate like steps or procedures. 
     In step S 912 , the image processing module  18  or the alignment module  24  determines the relative position of the spout  89 , or the spout end  87 , and the container perimeter  81  and for generating command data to the propelled portion to steer the storage portion  93  in cooperative alignment such that the spout  89  (or spout end  87 ) is aligned with a central zone  83  of the container perimeter  81 . The image processing module  18  may use, retrieve or access previously stored data, such as dimensional parameters related to the receiving vehicle, the dimensional parameters comprising a distance between a trailer hitch and front wheel rotational axis of the storage portion  93 . Such dimensional parameters may be entered via a user interface  44  coupled to the vehicle data bus  31  or the image processing module  18 , for example. 
     To execute step S 912 , the imaging processing module  18  may use first location data of a first location determining receiver  42  on the transferring vehicle and second location data of a second location determining receiver  142  on the receiving vehicle to determine one or more of the following: (1) a relative position of the first imaging device  10  and the second imaging device  12 , where the first imaging device  10  and the second imaging device  12  are on different vehicles or can experience relative movement with respect to each other, (2) a relative spatial separation between fixed reference points (e.g., antennas of the location determining receivers ( 42 ,  142 )) on the receiving and transferring vehicles, (3) relative alignment between the spout and the container perimeter, (4) spatial separation and angle between reference points on the transferring vehicle and receiving vehicle to achieve relative alignment or target spatial offset between the spout  89  and the container perimeter  81  to support reliable unloading of agricultural material into the container  85  of the receiving vehicle from the spout. If the first imaging device  10  and the second imaging device  12  are mounted to fixed portions of the same vehicle, the relative spatial alignment between the first imaging device  10  and the second imaging device  12  may be fixed. 
     In step S 914 , in a first configuration, the controller ( 59  or  159 ) or the steering controller  32  steers the receiving vehicle in accordance with the cooperative alignment. In a second configuration, the vehicle controller or the steering controller  32  may steer the transferring vehicle in accordance with the cooperative alignment. In a third configuration, the vehicle controller ( 59  or  159 ) or steering controllers  32  of both the transferring vehicle  91  and the receiving vehicle  79  steer both vehicles in accordance with the cooperative alignment, or maintenance of a target spatial offset suitable for unloading or transfer of the material between the vehicles. In a fourth configuration, the actuator  116  (e.g., a servo-motor, electric motor, linear motor and linear-to-rotational gear assembly, or electro-hydraulic device) controls the spout angle of the spout  89 , or the spout end  87 , with respect to the direct of travel or another reference axis of the transferring vehicle in response to alignment module  24  or the image processing module  18  (e.g., smart unloading controller). 
     Although the imaging devices  10 ,  12  are susceptible to transitory sunlight, shading, dust, reflections or other lighting conditions that can temporarily disrupt proper operation of the imaging devices in an agricultural environment; the system and methods disclosed in this document are well suited for reducing or eliminating the deleterious effects associated with material changes in ambient light conditions. Accordingly, the system and methods disclosed in this document support accurate guidance and alignment of the spout and the counter even where ambient light conditions fluctuate. 
     The method and system is well suited for enhancing the efficiency of unloading of a transferring vehicle (e.g., combine) to a receiving vehicle (e.g., tractor pulling a grain cart) by facilitating the velocity or speed matching of the vehicles via position data from location determining receivers, where fine tuning of the alignment of the spout end and the container perimeter is supported by image data from one or more imaging devices. In the absence of the method and system disclosed herein, the operator of the receiving vehicle tends to set a constant speed that is below the optimal speed for harvesting to avoid spilling agricultural material on the ground and missing the container of the receiving vehicle. Accordingly, the method and system is well suited for reducing the time to harvest a field and to collect the grain than otherwise possible. 
     While the disclosure has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the embodiments. Thus, it is intended that the present disclosure cover the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.