Patent Publication Number: US-2023133175-A1

Title: Object detection system and method for a work machine using work implement masking

Description:
FIELD OF THE DISCLOSURE 
     The present disclosure relates generally to work machines which include work implements mounted thereon, and to methods of detecting and classifying objects in a proximity thereof. More particularly, the present disclosure relates to object detection methods using image masking with respect to work implements mounted to a work machine in order to separate and favorably distinguish external objects in a field of view. 
     BACKGROUND 
     Conventional methods are known for detecting objects in the rear of a work machine or equivalent vehicle, but typically are only functional when there are no vehicle components protruding into the field of view for associated sensors. As but one example, an automotive rear parking sensor becomes non-functional when there is a bike rack or trailer attached to the hitch, therefore prompting the driver to turn off the system as it cannot differentiate the vehicle attachments from obstacles behind the vehicle. 
     Work machines as the primary subject of the present disclosure may for example include self-propelled vehicles such as dozers, compact track loaders, excavator machines, skid steer loaders, and the like which grade or otherwise modify the terrain or equivalent working environment in some way. However, the scope of the present disclosure further extends to work machines that are not self-propelled. Such work machines may include one or more work implements mounted to a main frame thereof, or otherwise extending from the main frame into an external reference area which may cause a dangerous condition for objects within a certain proximity of the work machine. When such work implements are rear-mounted, such as for example a ripper, tamping roller, or the like, conventional object detection systems would be subject to the same inability to differentiate external objects as discussed above for motor vehicle sensors. 
     BRIEF SUMMARY 
     The current disclosure provides an enhancement to conventional systems, at least in part by introducing a novel object detection system and method for identifying and differentiating objects proximate to rear-mounted work implements, without “false positive” detection of the work implements themselves. Such a system may desirably assist operators in maintaining situational awareness around the work implement, even throughout movement of the work machine and/or of the work implements relative to the main frame of the work machine. 
     A system as disclosed herein may utilize machine learning techniques to identify the geometry of a work implement and selectively apply an appropriate masking feature, wherein the work implement may be automatically tracked and dynamically masked for enhanced object detection. The system and method may also, or in the alternative, determine which work implements are connected to the machine by comparing a detected shape thereof to a library of implement shapes, wherein an appropriate mask may be dynamically selected. Work implements may include machine-readable components such as for example AprilTag tokens or the like to facilitate the tracking of implement orientation and accordingly dynamic movements of the applied mask. 
     In one particular embodiment, an object detection method is accordingly disclosed herein for a work machine comprising one or more work implements supported from a main frame. The method includes receiving, from at least one sensor (e.g., an image data source) associated with the work machine, data (e.g., image data) corresponding to a field of view extending from the main frame. The method further includes classifying objects in respective locations in the field of view, and generating at least one segmentation mask corresponding to contours for at least one portion of, or attachment to, the work machine as determined to be in the field of view, wherein each of the at least one segmentation mask defines a respective masked zone in the field of view. One or more of the classified objects may be determined to be separate from the at least one portion of, or attachment to, the work machine, wherein the at least one segmentation mask is applied to the at least one portion of, or attachment to, the work machine independently of any of the one or more separate objects in the field of view. 
     In one exemplary aspect according to the above-referenced embodiment, the method may further include generating images on a display unit corresponding to the field of view and having the at least one image segmentation mask applied thereto. 
     In another exemplary aspect according to the above-referenced embodiment, the method may further include, during movement of the work machine, detecting from the received data at least one static portion in the field of view and one or more dynamic portions relative thereto in the field of view, and generating the at least one segmentation mask corresponding to the detected at least one static portion in the field of view. 
     In another exemplary aspect according to the above-referenced embodiment, data corresponding to at least one portion of, and/or attachment to, the work machine may be retrieved and applied for generation of an associated segmentation mask based on user input. 
     In another exemplary aspect according to the above-referenced embodiment, the user input comprises a user selection from among a library of selectable portions of and/or attachments to the work machine. 
     In another exemplary aspect according to the above-referenced embodiment, the method further includes dynamically generating the at least one segmentation mask based on determined movements of an attachment to the work machine relative to the field of view. 
     In another exemplary aspect according to the above-referenced embodiment, the movements of the attachment may be determined based on detected steering signals for the work machine. 
     In another exemplary aspect according to the above-referenced embodiment, the movements of the attachment are determined based on first input signals from a sensor associated with the attachment and second input signals from a sensor associated with the work machine. 
     In another exemplary aspect according to the above-referenced embodiment, a bounding region for the at least one portion of, or attachment to, the work machine may be determined via image classification from the received data. 
     In another exemplary aspect according to the above-referenced embodiment, a bounding region for the at least one portion of, or attachment to, the work machine may be determined at least in part via output signals from one or more movement sensors associated with the respective portion of, or attachment to, the work machine. 
     In another exemplary aspect according to the above-referenced embodiment, a bounding region for the at least one portion of, or attachment to, the work machine may be determined by scanning a machine readable tag associated with the respective at least one portion of, or attachment to, the work machine and retrieving bounding region data corresponding to the respective at least one portion of, or attachment to, the work machine from data storage based on the scanned machine readable tag. 
     In another exemplary aspect according to the above-referenced embodiment, the method may further include detecting respective positions of the one or more further objects determined to be in the respective field of view, relative to the work machine and/or the at least one portion of, or attachment to, the work machine, and conditionally generating output signals corresponding to at least an identified unsafe position of an object relative to at least one of the work machine and/or the at least one portion of, or attachment to, the work machine. 
     In another embodiment, a work machine as disclosed herein may comprise a main frame supported by one or more ground engaging units, one or more work implements supported from the main frame, and at least one sensor (e.g., at least one image data source) configured to generate data (e.g., image data) corresponding to a field of view extending from the main frame. A controller is linked to receive the data from the at least one sensor, and configured to direct the performance of a method according to the above-referenced embodiment and optionally any one or more of the associated aspects. 
     In another embodiment, a non-transitory computer readable medium as disclosed herein may have a computer program residing thereon and executable by a processor to direct the performance of a method according to the above-referenced embodiment and optionally any one or more of the associated aspects. 
     Numerous objects, features and advantages of the embodiments set forth herein will be readily apparent to those skilled in the art upon reading of the following disclosure when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a tracked work machine incorporating an embodiment of a work machine and method as disclosed herein. 
         FIG.  2    is a block diagram representing an exemplary control system for the work machine according to an embodiment as disclosed herein. 
         FIGS.  3 A- 3 C  are perspective views representing an exemplary rear-view camera image, an initial classification of objects in the camera image, and an object separation with an image segmentation mask applied to a portion of the camera image, respectively. 
         FIG.  4 A  is a side view representing an exemplary work machine and field of view for a camera mounted to a rear portion thereof, including a human standing behind a rear-mounted work implement. 
         FIG.  4 B  is a perspective view from the work machine of  FIG.  4 A , representing the human separable by the system from the rear-mounted work implement in the field of view. 
         FIG.  5 A  is a side view representing an exemplary tracked work machine and field of view for a camera mounted to a rear portion thereof, including a human between a rear-mounted work implement and the machine tracks. 
         FIG.  5 B  is a perspective view from the work machine of  FIG.  5 A , representing the human separable by the system from the rear-mounted work implement in the field of view. 
         FIG.  6 A  is a top view representing an exemplary work machine and image segmentation mask applied within a field of view for a camera mounted to a rear portion thereof. 
         FIG.  6 B  is a top view representing the work machine of  FIG.  6 A , with the image segmentation mask being dynamically applied with respect to movement of the work implement relative to the main frame of the work machine. 
         FIG.  7    is a flowchart representing an exemplary embodiment of a method as disclosed herein. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    is a perspective view of a work machine  100 . In the illustrated embodiment, the work machine  100  is a crawler dozer having a front-mounted work implement  130  (e.g., ground-engaging blade) and a rear-mounted work implement  162  (e.g., ripper), but may include any of various alternative implement configurations (e.g., rear only) or work machines  100  such as a compact track loader, motor grader, scraper, skid steer, backhoe, and tractor, to name but a few examples. While operating, the work machine may experience movement in three directions and rotation in three directions. A direction for the work machine may also be referred to with regard to a longitudinal direction  102 , a latitudinal or lateral direction  106 , and a vertical direction  110 . Rotation for work machine  100  may be referred to as roll  104  or the roll direction, pitch  108  or the pitch direction, and yaw  112  or the yaw direction or heading. 
     An operator&#39;s cab  136  may be located on the main frame  140 . The operator&#39;s cab and a front-mounted working implement  130  may both be mounted on the main frame  140  so that at least in certain embodiments the operator&#39;s cab faces in the working direction of the working implement  130 . A control station including a user interface  142  with a display unit may be located in the operator&#39;s cab  136 . As used herein, directions with regard to work machine  100  may be referred to from the perspective of an operator seated within the operator cab  136 : the left of work machine is to the left of such an operator, the right of work machine is to the right of such an operator, the front or fore of work machine  100  is the direction such an operator faces, the rear or aft of work machine is behind such an operator, the top of work machine is above such an operator, and the bottom of work machine is below such an operator. 
     The term “user interface”  142  as used herein may broadly take the form of a display unit and/or other outputs from the system such as indicator lights, audible alerts, and the like. The user interface may further or alternatively include various controls or user inputs (e.g., a steering wheel, joysticks, levers, buttons) for operating the work machine  100 , including operation of the engine, hydraulic cylinders, and the like. Such an onboard user interface may be coupled to a vehicle control system via for example a CAN bus arrangement or other equivalent forms of electrical and/or electro-mechanical signal transmission. Another form of user interface (not shown) may take the form of a display unit (not shown) that is generated on a remote (i.e., not onboard) computing device, which may display outputs such as status indications and/or otherwise enable user interaction such as the providing of inputs to the system. In the context of a remote user interface, data transmission between for example the vehicle control system and the user interface may take the form of a wireless communications system and associated components as are conventionally known in the art. 
     The illustrated work machine  100  further includes a control system including a controller  138  (further described below with respect to  FIG.  3   ). The controller  138  may be part of the machine control system of the work machine, or it may be a separate control module. Accordingly, the controller  138  may generate control signals for controlling the operation of various actuators throughout the work machine  100 , which may for example be hydraulic motors, hydraulic piston-cylinder units, electric actuators, or the like. Electronic control signals from the controller may for example be received by electro-hydraulic control valves associated with respective actuators, wherein the electro-hydraulic control valves control the flow of hydraulic fluid to and from the respective hydraulic actuators to control the actuation thereof in response to the control signal from the controller. 
     The controller  138  may include or be functionally linked to the user interface  142  and optionally be mounted in the operators cab  136  at a control panel. 
     The controller  138  is configured to receive input signals from some or all of various sensors associated with the work machine  100 , which may include for example one or more sensors  132  associated with a front-mounted work implement  130 , a set of one or more sensors  144  affixed to the main frame  140  of the work machine  100  and configured to provide signals indicative of, e.g., an inclination (slope) of the main frame or the blade, and a set of one or more sensors  164  affixed to for example a rear-mounted work implement  162  and configured to provide signals indicative of a relative position thereof. In alternative embodiments, such sensors  132 ,  144 ,  164  may not be affixed directly to the referenced components but may instead be connected indirectly through intermediate components or structures, such as rubberized mounts. For example, sensor  144  may not be directly affixed to the main frame  140  but still connected to the frame at a fixed relative position so as to experience the same motion as the main frame. 
     The sensor(s)  144  may be configured to provide at least a signal indicative of the inclination of the main frame  140  relative to the direction of gravity, or to provide a signal or signals indicative of other positions or velocities of the frame, including its angular position, velocity, or acceleration in a direction such as the direction of roll  104 , pitch  108 , yaw  112 , or its linear acceleration in a longitudinal  102 , latitudinal  106 , and/or vertical  110  direction. Sensors may be configured to directly measure inclination, or for example to measure angular velocity and integrate to arrive at inclination, and may typically, e.g., be comprised of an inertial measurement unit (IMU) mounted on the main frame  140  and configured to provide for example a work machine inclination (slope) signal, or equivalent signals corresponding to the slope of the frame  140 , as inputs to the controller  138 . Such an IMU  144  may for example be in the form of a three-axis gyroscopic unit configured to detect changes in orientation of the sensor, and thus of the frame  140  to which it is fixed, relative to an initial orientation. 
     In other embodiments, the sensors may include a plurality of GPS sensing units fixed relative to the main frame  140  or work implement  130 ,  162 , which can detect the absolute position and orientation of the work machine  100  or components thereof within an external reference system, and can detect changes in such position and orientation. 
     An image data source  170  such as for example a stereo camera  170  may be coupled to the work machine  100 , for example at an elevated rear portion of the main frame  140  and arranged to provide a field of view  172  encompassing at least a rear-mounted work implement  162  and objects proximate thereto. The image data source  170  is functionally linked to the controller  138  as further described herein for image processing features and steps. 
     The controller  138  in an embodiment (not shown) may include or may be associated with a processor, a computer readable medium, a communication unit, data storage  178  such as for example a database network, and the aforementioned user interface  142  or control panel having a display. An input/output device, such as a keyboard, joystick or other user interface tool, may be provided so that the human operator may input instructions to the controller  138 . It is understood that the controller described herein may be a single controller having all of the described functionality, or it may include multiple controllers wherein the described functionality is distributed among the multiple controllers. 
     Various operations, steps or algorithms as described in connection with the controller  138  can be embodied directly in hardware, in a computer program product such as a software module executed by a processor, or in a combination of the two. The computer program product can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, or any other form of computer-readable medium known in the art. An exemplary computer-readable medium can be coupled to the processor such that the processor can read information from, and write information to, the memory/storage medium. In the alternative, the medium can be integral to the processor. The processor and the medium can reside in an application specific integrated circuit (ASIC). The ASIC can reside in a user terminal. In the alternative, the processor and the medium can reside as discrete components in a user terminal. 
     The term “processor” as used herein may refer to at least general-purpose or specific-purpose processing devices and/or logic as may be understood by one of skill in the art, including but not limited to a microprocessor, a microcontroller, a state machine, and the like. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     The communication unit may support or provide communications between the controller  138  and external systems or devices, and/or support or provide communication interface with respect to internal components of the work machine  100 . The communications unit may include wireless communication system components (e.g., via cellular modem, WiFi, Bluetooth or the like) and/or may include one or more wired communications terminals such as universal serial bus ports. 
     Data storage  178  as discussed herein may, unless otherwise stated, generally encompass hardware such as volatile or non-volatile storage devices, drives, memory, or other storage media, as well as one or more databases residing thereon. 
     The work machine  100  is supported on the ground by an undercarriage  114 . The undercarriage  114  includes ground engaging units  116 ,  118 , which in the present example are formed by a left track  116  and a right track  118 , and provide tractive force for the work machine  100 . Each track may be comprised of shoes with grousers that sink into the ground to increase traction, and interconnecting components that allow the tracks to rotate about front idlers  120 , track rollers  122 , rear sprockets  124  and top idlers  126 . Such interconnecting components may include links, pins, bushings, and guides, to name a few components. Front idlers  120 , track rollers  122 , and rear sprockets  124 , on both the left and right sides of the work machine  100 , provide support for the work machine  100  on the ground. Front idlers  120 , track rollers  122 , rear sprockets  124 , and top idlers  126  are all pivotally connected to the remainder of the work machine  100  and rotationally coupled to their respective tracks so as to rotate with those tracks. The track frame  128  provides structural support or strength to these components and the remainder of the undercarriage  114 . In alternative embodiments, the ground engaging units  116 ,  118  may comprise, e.g., wheels on the left and right sides of the work machine. 
     Front idlers  120  are positioned at the longitudinal front of the left track  116  and the right track  118  and provide a rotating surface for the tracks to rotate about and a support point to transfer force between the work machine  100  and the ground. The left and right tracks  116 ,  118  rotate about the front idlers  120  as they transition between their vertically lower and vertically upper portions parallel to the ground, so approximately half of the outer diameter of each of the front idlers  120  is engaged with the respective left  116  or right track  118 . This engagement may be through a sprocket and pin arrangement, where pins included in the left  116  and right tracks  118  are engaged by recesses in the front idler  120  so as to transfer force. This engagement also results in the vertical height of the left and right tracks  116 ,  118  being only slightly larger than the outer diameter of each of the front idlers  120  at the longitudinal front of the tracks. Forward engaging points  130  of the tracks  116 ,  118  can be approximated as the point on each track vertically below the center of the front idlers  120 , which is the forward point of the tracks which engages the ground. 
     Track rollers  122  are longitudinally positioned between the front idler  120  and the rear sprocket  124  along the bottom left and bottom right sides of the work machine  100 . Each of the track rollers  122  may be rotationally coupled to the left track  116  or the right track  118  through engagement between an upper surface of the tracks and a lower surface of the track rollers  122 . This configuration may allow the track rollers  122  to provide support to the work machine  100 , and in particular may allow for the transfer of forces in the vertical direction between the work machine and the ground. This configuration also resists the upward deflection of the left and right tracks  116 ,  118  as they traverse an upward ground feature whose longitudinal length is less than the distance between the front idler  120  and the rear sprocket  124 . 
     Rear sprockets  124  may be positioned at the longitudinal rear of each of the left track  116  and the right track  118  and, similar to the front idlers  120 , provide a rotating surface for the tracks to rotate about and a support point to transfer force between the work machine  100  and the ground. The left and right tracks  116 ,  118  rotate about the rear sprockets as they transition between their vertically lower and vertically upper portions parallel to the ground, so approximately half of the outer diameter of each of the rear sprockets  124  is engaged with the respective left or right track  116 ,  118 . This engagement may be through a sprocket and pin arrangement, where pins included in the left and right tracks are engaged by recesses in the rear sprockets  124  to transfer force. This engagement also results in the vertical heights of the tracks being only slightly larger than the outer diameter of each of the rear sprockets  124  at the longitudinal back or rear of the respective track. The rearmost engaging point of the tracks can be approximated as the point on each track vertically below the center of the rear sprockets, which is the rearmost point of the track which engages the ground. In this embodiment, each of the rear sprockets  124  may be powered by a rotationally coupled hydraulic motor so as to drive the left track  116  and the right track  118  and thereby control propulsion and traction for the work machine  100 . Each of the left and right hydraulic motors may receive pressurized hydraulic fluid from a hydrostatic pump whose direction of flow and displacement controls the direction of rotation and speed of rotation for the left and right hydraulic motors. Each hydrostatic pump may be driven by an engine  134  (or equivalent power source) of the work machine and may be controlled by an operator in the operator cab  136  issuing commands which may be received by the controller  138  and communicated to the left and right hydrostatic pumps. In alternative embodiments, each of the rear sprockets may be driven by a rotationally coupled electric motor or a mechanical system transmitting power from the engine. 
     Top idlers  126  are longitudinally positioned between the front idlers  120  and the rear sprockets  124  along the left and right sides of the work machine  100  above the track rollers  122 . Similar to the track rollers, each of the top idlers may be rotationally coupled to the left track  116  or the right track  118  through engagement between a lower surface of the tracks and an upper surface of the top idlers. This configuration may allow the top idlers to support the tracks for the longitudinal span between the front idler and the rear sprocket and prevent downward deflection of the upper portion of the tracks parallel to the ground between the front idler and the rear sprocket. 
     The blade assembly  130  as represented in the embodiment of  FIG.  1    is a front-mounted work implement  130  which may engage the ground or material, for example to move material from one location to another and to create features on the ground, including flat areas, grades, hills, roads, or more complexly shaped features. The blade  130  is movably connected to the main frame  140  of the work machine  100  through a linkage  146  which supports and actuates the blade and is configured to allow the blade to be lifted (i.e., raised or lowered in the vertical direction  110 ) relative to the main frame. The linkage  146  includes a c-frame  148 , a structural member with a C-shape positioned rearward of the blade  130 , with the C-shape open toward the rear of the work machine  100 . The blade  130  may be lifted (i.e., raised or lowered) relative to the work machine  100  by the actuation of lift cylinders  150 , which may raise and lower the c-frame  148 . The blade  130  may be tilted relative to the work machine  100  by the actuation of a tilt cylinder  152 , which may also be referred to as moving the blade in the direction of roll  104 . The blade  130  may be angled relative to the work machine  100  by the actuation of angle cylinders  154 , which may also be referred to as moving the blade in the direction of yaw  112 . Each of the lift cylinders  150 , tilt cylinder  152 , and angle cylinders  154  may for example be a double acting hydraulic cylinder. 
     The ripper assembly  162  as represented in the embodiment of  FIG.  1    is a rear-mounted work implement  162  which also may selectively engage the ground or material, for example to loosen the ground behind the work machine  100 . The ripper assembly  162  as shown includes a plurality of (e.g., three) separate ripper shanks which are typically substantially perpendicular to the ground. When the ripper is not in use, the shanks may be raised so that they are not in contact with the ground. Alternatively, when the ripper is in use, the shanks may be lowered to penetrate the ground surface and thereby loosen the ground as the work machine proceeds. 
     As schematically illustrated in  FIG.  2   , the work machine  100  in an embodiment as disclosed herein includes a control system  200  including a controller  138 . The controller  138  may be part of the machine control system of the work machine  100 , or it may be a separate control module. The control system  200  may include hydraulic and electrical components for controlling respective positions of the front-mounted  130  and/or rear-mounted  162  work implements. For example with respect to the blade  130 , each of the lift cylinders  150 , the tilt cylinder  152 , and the angle cylinders  154  is hydraulically connected to a hydraulic control valve  156 , which receives pressurized hydraulic fluid from a hydraulic pump  158 , which may be rotationally connected to the engine  134 , and directs such fluid to the lift cylinders, the tilt cylinder, the angle cylinders, and other hydraulic circuits or functions of the work machine. The hydraulic control valve may meter such fluid out, or control the flow rate of hydraulic fluid to each hydraulic circuit to which it is connected. In alternative embodiments, the hydraulic control valve may not meter such fluid out but may instead only selectively provide flow paths to these functions while metering is performed by another component (e.g., a variable displacement hydraulic pump) or not performed at all. The hydraulic control valve may meter such fluid out through a plurality of spools, whose positions control the flow of hydraulic fluid, and other hydraulic logic. The spools may be actuated by solenoids, pilots (e.g., pressurized hydraulic fluid acting on the spool), the pressure upstream or downstream of the spool, or some combination of these and other elements. 
     In various embodiments, the controller  138  may send commands to actuate work implements  130 ,  162  in a number of different manners. As one example, the controller  138  may be in communication with a valve controller via a controlled area network (CAN) and may send command signals to the valve controller in the form of CAN messages. The valve controller may receive these messages from the controller and send current to specific solenoids within the electrohydraulic pilot valve  160  based on those messages. As another example, the controller may actuate a work implement  130 ,  162  by actuating an input in the operator cab  136 . For example, an operator may use a joystick to issue commands to actuate the blade  130 , and the joystick may generate hydraulic pressure signals, pilots, which are communicated to the hydraulic control valve  156  to cause the actuation of the blade. In such a configuration, the controller may be in communication with electrical devices (e.g., solenoids, motors) which may actuate a joystick in the operator cab. In this way, the controller may actuate the blade by actuating these electrical devices instead of communicating signals to electrohydraulic pilot valve. 
     As referenced above, the controller  138  is configured to receive input signals from some or all of various sensors  170  which may include image data sources such as cameras and collectively defining an imaging system. The sensors  170  may include video cameras configured to record an original image stream and transmit corresponding data to the controller  138 . In the alternative or in addition, the sensors  170  may include one or more of an infrared camera, a stereoscopic camera, a PMD camera, high resolution light detection and ranging (LiDAR) scanners, radar detectors, laser scanners, and the like within the scope of the present disclosure. The number and orientation of said sensors  170  may vary in accordance with the type of work machine  100  and relevant applications, but may at least be provided with respect to a field of view  172  rearward of the work machine  100  and configured to capture image data associated with surroundings including for example the rear-mounted work implement  162  and other objects proximate thereto. 
     The position and size of an image region recorded by a respective camera as a sensor  170  may depend on the arrangement and orientation of the camera and the camera lens system, in particular the focal length of the lens of the camera. One of skill in the art may further appreciate that image data processing functions may be performed discretely at a given image data source if properly configured, but also or otherwise may generally include at least some image data processing by the controller or other downstream data processor. For example, image data from any one or more image data sources may be provided for three-dimensional point cloud generation, image segmentation, object delineation and classification, and the like, using image data processing tools as are known in the art in combination with the objectives disclosed. 
     The controller  138  of the work machine  100  may be configured to produce outputs, as further described below, to a user interface  142  associated with a display unit for display to the human operator. The controller  138  may be configured to receive inputs from the user interface  142 , such as user input provided via the user interface  142 . Not specifically represented in  FIG.  2   , the controller  138  of the work machine  100  may in some embodiments further receive inputs from and generate outputs to remote devices associated with a user via a respective user interface, for example a display unit with touchscreen interface. Data transmission between for example the vehicle control system and a remote user interface may take the form of a wireless communications system and associated components as are conventionally known in the art. In certain embodiments, a remote user interface and vehicle control systems for respective work machines may be further coordinated or otherwise interact with a remote server or other computing device for the performance of operations in a system as disclosed herein. 
     The controller  138  may in various embodiments, as part of the control system of  FIG.  2    and further in line with the above-referenced disclosure, be functionally linked to a reading device  166  as conventionally known in the art such as for example an RFID device, barcode scanner, or the like for obtaining readable information. The reading device  166  may be a discrete device, or in other embodiments may include a data processing module in combination with image data or equivalent data captured by the sensor  170 . For example, a work implement  130 ,  162  within a field of view  172  of a camera as the sensor  170  may have a barcode or equivalent tags (e.g., AprilTags)  166  associated with machine readable information, which may as further described herein be used to identify and/or retrieve information associated with the work implement. 
     In an embodiment as shown, the controller  138  may further be functionally linked to a work machine movement control system  168 , wherein for example the controller may directly or indirectly generate output signals for controlling the steering and/or advance speed of the work machine  100 . The controller  138  may alternatively or in addition receive input signals from the movement control system  168  indicative of the steering and/or advance speed of the work machine  100 . 
     An embodiment of a method  400  of the present disclosure may now be described with further illustrative reference to  FIGS.  3 - 7   . The present embodiment is intended as illustrative and the associated description is not limiting on the scope of any other embodiments unless otherwise specifically noted herein. It should also be noted that various steps as disclosed in accordance with the present embodiment may be combined, omitted, or supplemented by one of skill in the art when considering the applicable functions and without necessarily altering the scope of the present disclosure, unless otherwise expressly provided herein. 
     The exemplary method  400  as illustrated begins in step  410  by capturing data (e.g., image data) in at least one field of view  172 . As further described below, the relevant field of view is associated with a rear-mounted camera as a sensor  170  and comprises surroundings at least to the rear of the work machine  100 . 
     In step  420 , the system (via the controller  138  directly, or indirectly via one or more associated image processing components or modules) classifies objects in respective locations in the field of view  172 , and further determines from the captured data whether a portion of the work machine  100  or an attachment thereto, such as for example rear-mounted work implement  162 , is present in the field of view  172 . 
     Such a determination may be accomplished in numerous ways within the scope of the present disclosure. For example, in step  430  as shown, the system obtains information regarding for example physical contours of the work implement  162  and generates a bounding region  174  about said contours. The bounding region  174  may be a relatively simple three-dimensional polyhedron as illustrated in the figures, or in other embodiments may include any number of sides, angles, curved faces, or the like as better or more precisely corresponding with the actual contours of the work implement  162 . In certain embodiments wherein the perspective is substantially horizontal or substantially vertical in orientation (e.g., a bird&#39;s eye view) the bounding region  174  and the associated image segmentation mask  176  as further described below may be a relatively simple two-dimensional polygon, or may include any number of sides, angles, curved faces, or the like as better or more precisely corresponding with the actual contours of the work implement  162 . 
     In various embodiments, the information regarding a presence and/or physical contours of the work implement  162  may be obtained in one or more of numerous forms. In one example as referenced above (step  412 ), machine readable tags such as for example AprilTags, RFID tags and the like may be provided on the work implement  162  itself, such that scanning of the tags enables simple retrieval of the associated information (e.g., a type of work implement or more specific information regarding the unique implement itself) by the controller  138 . In another example (step  414 ), conventional image classification techniques may be utilized to recognize the presence and/or at least roughly determine contours of the work implement  162 . For example, the system may be configured to ascertain a work implement  162  or type of work implement that is coupled to the work machine  100  by comparing a detected shape to a library of work implement shapes, wherein an appropriate image segmentation mask may be selected. In another example (step  416 ), movement and/or position sensors  164  associated with the work implement  162  may generate output signals to the controller  138  which, taken alone or further in combination with one or more other sensors  132 ,  144  may be indicative of a position of the rear-mounted implement  162  or a likelihood that the implement  162  is in the relevant field of view  172 . 
     In step  440 , the system applies at least one image segmentation mask  176  in association with the generated bounding region  174 , and independently of any objects determined to be separate from portions of the work machine  100  or attachments (e.g., work implements  162 ) thereto and extending into the field of view  172 . In step  442 , the system generates a display on the display unit  142  in the operator cab, or in some embodiments a remote display unit, with a masked area corresponding to the image segmentation mask  176 . Such a display may comprise images from the same rear-view perspective as an orientation of the associated sensor  170 , or in various embodiments may comprise a top-down (e.g., bird&#39;s eye) view, surround view, or other views as may be for example generated by stitching together images from a plurality of sensors  170 . Where a number of views are available, user selection from among such views may optionally be enabled via the user interface. In an embodiment, the masked area may not be simply obscured but rather augmentation may be utilized to generate an image corresponding to objects in an area behind the masked area, for example using additional cameras that are not obscured in the relevant area by the same work implement  162 . In step  444 , the system performs an object detection and/or recognition function utilizing the image segmentation mask  176 , or otherwise stated an image segmentation mask may facilitate object separation such that objects other than the masked work implement  162  may be reliably detected and/or recognized by the system. 
     In one example, with reference to a camera view from the upper rear portion of a work machine  100  as shown in  FIG.  3 A , a first object  310  is alongside the rear-mounted work implement  162  and a second object  320  is behind the rear-mounted work implement  162 . A digitized image classification may be unable to reliably distinguish the first object  310 , second object  320 , and work implement  162 , as represented for example in  FIG.  3 B . A depth disparity view according to conventional image processing techniques may indicate that the second object  320  is not at the same depth as the work implement  162 , but would typically be unable to distinguish the first object  310  and the work implement  162  as being at the same depth. With an appropriate bounding region  174  and an associated image segmentation mask  176  applied to the work implement  162 , however, the work implement  162  may be ignored and the various objects  310 ,  320  reliably separated by the image processing system for the purpose of determining their respective identities, locations, movements, or the like. 
     In various embodiments, the form of the bounding region  174  and the associated image segmentation mask  176  may substantially correlate with the contours of the work implement  162  itself, for example where detailed information regarding said contours is available for retrieval upon identifying the particular work implement and/or current orientation thereof using machine readable tags or the like. In other embodiments, the form of the bounding region  174  and/or the image segmentation mask  176  may be more generalized. A more detailed bounding region  174  and image segmentation mask  176  may typically be preferred, as may be illustrated for example by reference to  FIGS.  4 A,  4 B,  5 A , and  5 B. 
     As represented in  FIG.  4 A , an object  310  (a human in the present example) is standing in the field of view  172  of a rear-mounted camera as sensor  170 , behind the rear-mounted work implement  162 . A bounding region  174  about the work implement  162  in the present example does not need to be highly precise, as further illustrated by reference to  FIG.  4 B . The corresponding image segmentation mask  176  may be applied to enable separation of the object  310  from the work implement  162  in a straightforward manner. As represented in  FIG.  5 A , however, the object  310  is still in the field of view  172  of the camera as sensor  170  but is now present between the work implement  162  and the main frame  140  of the work machine  100 . If the image segmentation mask  176  were to be applied broadly with respect to a simple geometrically defined bounding region  174 , appropriate separation of the object  310  may not be possible. Accordingly, a more precisely defined bounding region  174  and image segmentation mask  176  with respect to the contours of the respective work implement  162  may be preferable for at least this context, wherein an object  310  in close proximity to the work machine  100  may be reliably separated and identified by elements of the system. 
     In step  450 , the system may be configured to generate any alerts that may be triggered by or otherwise appropriate in view of the object detection and/or recognition function. For example, if an object is recognized as being in a dangerous location relative to a position of the work implement, or otherwise in view of a predicted movement of the work machine and/or work implement, an alert may be generated in the form of an audio alarm, a visual alert on the display unit, or the like. 
     The type of alert may be dependent at least in part on the type of object, wherein for example a living creature as a first type of differentiated object in the field of view may result in a first and more urgent form of alert whereas a second type of differentiated object in the form of for example debris may result in a second and less urgent form of alert. In some embodiments this determination may be made in view of the above-referenced object detection and/or recognition function, further in view of a machine geometry or pose detection function which determines if the work implement  162  is in a position or orientation corresponding with for example a first work state (i.e., at rest and therefore of reduced risk to a proximate object) or a second work state (i.e., an active state and therefore of potentially heightened risk to a proximate object). 
     An alert according to step  450  may be generated visually for the benefit of the operator, and/or may include output signals generated to prevent actuation of the work implement  162  or other elements of the work machine  100  that could cause a collision or other intersection with a detected and/or recognized object. 
     Alert functions may be generated in certain embodiments in association with a predetermined threshold for a given work implement  162 , a variable threshold depending on a work state or condition of the given work implement  162 , and/or a non-threshold determination made further in view of factors including for example a detected movement of the object(s), detected movement of the work implement  162 , predicted movements of the object(s) and/or work implement  162 , type of terrain being traversed by the work machine  100 , orientation of the work machine  100 , and the like. 
     In some embodiments and further with reference to step  460 , the system may be configured to determine whether the work implement  162  is moving or whether such movement is predicted in the field of view  172 , and then accordingly to dynamically adjust application of the bounding region  174  and the corresponding at least one image segmentation mask  176  so that the masked region persists with an actual position of the work implement  162  in the field of view  172 . 
     Movement of the work implement  162  may for example be determined and/or predicted using the above-referenced inputs (step  416 ) from implement-mounted sensors  164 , and/or using inputs received (step  418 ) from the work machine steering control system  168 . Regardless of whether the rear-mounted work implement  162  is a ripper assembly which substantially moves along with movement of the work machine frame  140 , or a towed implement such as a tamping roller which is pivotally coupled about a vertical axis to the work machine frame  140 , movement of the work implement may reliably be predicted based on knowledge of the type of attachment even if means are not available for directly sensing movement relative to the field of view  172 . 
     As used herein, the phrase “one or more of,” when used with a list of items, means that different combinations of one or more of the items may be used and only one of each item in the list may be needed. For example, “one or more of” item A, item B, and item C may include, for example, without limitation, item A or item A and item B. This example also may include item A, item B, and item C, or item B and item C. 
     Thus, it is seen that the apparatus and methods of the present disclosure readily achieve the ends and advantages mentioned as well as those inherent therein. While certain preferred embodiments of the disclosure have been illustrated and described for present purposes, numerous changes in the arrangement and construction of parts and steps may be made by those skilled in the art, which changes are encompassed within the scope and spirit of the present disclosure as defined by the appended claims. Each disclosed feature or embodiment may be combined with any of the other disclosed features or embodiments.