Camera monitoring system trailer backing trajectory overlay with vehicle speed-based correction

Abstract

The invention provides a camera monitoring system trailer backing trajectory overlay with vehicle speed based correction. A method of determining a trailer trajectory of a trailer comprises the steps of, while the trailer moves, determining a trailer position based on at least one captured image, determining a trailer angular rate of change based on the at least one captured image, determining a trailer trajectory based on the trailer position and the trailer angular rate of change, and displaying an overlay associated with the trailer trajectory. When the trailer is below a threshold speed, the method includes the steps of determining a change in steering, modifying a trailer trajectory based on the change in steering, and displaying a modified overlay associated with the trailer trajectory based on the change in steering.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a camera monitoring system (CMS) for use in a vehicle pulling a trailer, and in particular to a system for displaying a trajectory of an intended trailer path during a reversing maneuver. BACKGROUND

[0002] Mirror replacement systems and camera systems for supplementing mirror views are used in commercial vehicles to enhance the ability of the vehicle operator to see the surrounding environment. Camera monitoring systems (CMS) utilize one or more cameras positioned around the vehicle to provide the vehicle operator with an enhanced field of view. In some examples, mirror replacement systems within a CMS can cover a larger field of view than a conventional mirror, or can include views that are not fully available via a conventional mirror.

[0003] The area behind the trailer is a typical blind spot in conventional mirror systems, making it difficult to perform a reversing maneuver when attaching a trailer. Further complicating vehicle operation is the fact that trailer motion during a reversing maneuver is different from trailer motion during a forward maneuver, and driver assist systems and estimation techniques available for forward maneuvering are typically not available during a reversing maneuver.

[0004] A method for determining a trailer trajectory during a reversing maneuver has several drawbacks, for example, it does not take into account the effect of the towing vehicle's steering angle. When the driver changes the steering wheel at zero vehicle speed, the predicted path cannot be updated. When the trailer angular velocity is large, the previous prediction model loses accuracy and performance degrades for maneuvers with fast trailer turns. The previous prediction model assumes that the trailer angular velocity remains constant over the prediction horizon, which is incorrect because the trailer angular velocity can vary depending on the vehicle dynamics. This assumption can lead to large long-term prediction errors.

[0005] However, using the steering angle of the towing vehicle can also be inaccurate. Therefore, another method for determining a trailer trajectory during a reversing maneuver is also lacking. For example, this method does not take into account the motion of the towing vehicle and the trailer speed, and only uses a simple virtual steering angle of the trailer (to generate a radius arc) to calculate its predicted path. Therefore, this method will be very inaccurate. SUMMARY

[0006] In one example embodiment, a method of determining a trailer trajectory of a trailer includes the steps of: a) while the trailer is moving, a1) determining a trailer position based on at least one captured image, a2) determining a trailer angle rate of change based on the at least one captured image, a3) determining the trailer trajectory based on the trailer position and the trailer angle rate of change, a4) displaying an overlay related to the trailer trajectory, b) while the trailer is below a threshold speed, b1) determining a steering change, b2) revising the trailer trajectory based on the steering change, and b3) displaying a revised overlay related to the trailer trajectory based on the steering change.

[0007] In a further embodiment of any of the above embodiments, steps a) and b) are performed while the trailer is backing up.

[0008] In a further embodiment of any of the above embodiments, step a1) is performed by identifying at least one of a trailer wheel and a trailer end.

[0009] In a further embodiment of any of the above embodiments, step a2) is performed by determining a trailer angle, a change in the trailer angle over an interval, and a change in the trailer position over the interval.

[0010] In a further embodiment of any of the above embodiments, the interval is at least one of a time and a distance.

[0011] In a further embodiment of any of the above embodiments, step a3) is performed using the trailer position over the interval.

[0012] In a further embodiment of any of the above embodiments, steps a4) and b3) are performed by displaying the overlay of the trailer trajectory on a displayed captured image.

[0013] In a further embodiment of any of the above embodiments, the displayed captured image is different than the at least one captured image.

[0014] In a further embodiment of any of the above embodiments, the displayed captured image is a portion of an aerial view or a trailer rear view.

[0015] In a further embodiment of any of the above embodiments, the displayed captured image is the same as the at least one captured image.

[0016] In a further embodiment of any of the above embodiments, the threshold speed is 2 miles per hour.

[0017] In a further embodiment of any of the above embodiments, the threshold speed is zero miles per hour.

[0018] In a further embodiment of any of the above embodiments, the trailer angle rate of change is zero.

[0019] In further embodiments of any of the above embodiments, step bl) is performed by obtaining the steering angle from a CAN bus.

[0020] In another exemplary embodiment, a camera monitoring system (CMS) for a vehicle comprises: at least one rear-facing camera configured to obtain at least one captured image; at least one display configured to depict the at least one captured image; a CMS controller comprising a memory and a processor, the CMS controller in communication with the at least one rear-facing camera and the at least one display, the memory storing instructions for causing the processor to: a) while the trailer is moving, al) determine a trailer position based on the at least one captured image, a2) determine a trailer rate of angle change based on the at least one captured image, a3) determine a trailer trajectory based on the trailer position and the trailer rate of angle change, a4) display an overlay related to the trailer trajectory on one of the at least one display, b) while the trailer is below a threshold speed, bl) determine a steering change, b2) revise the trailer trajectory based on the steering change, and b3) display a revised overlay related to the trailer trajectory based on the steering change.

[0021] In further embodiments of any of the above embodiments, steps a) and b) are performed while the trailer is backing up, and step bl) is performed by obtaining the steering angle from a CAN bus.

[0022] In further embodiments of any of the above embodiments, step al) is performed by identifying at least one of a trailer wheel and a trailer end, step a2) is performed by determining a trailer angle, a change in the trailer angle over an interval, and a change in the trailer position over the interval, and step a3) is performed using the trailer position over the interval.

[0023] In further embodiments of any of the above embodiments, steps a4) and b3) are performed by displaying the overlay of the trailer trajectory on the displayed captured image.

[0024] In further embodiments of any of the above embodiments, the threshold speed is 2 miles per hour.

[0025] In further embodiments of any of the above embodiments, the threshold speed is zero miles per hour. The trailer rate of angle change is zero. BRIEF DESCRIPTION OF DRAWINGS

[0026] The present disclosure can be further understood by reference to the following detailed description when considered in connection with the following drawings, in which:

[0027] Figure 1A This is a schematic front view of a commercial truck equipped with a Camera Monitoring System (CMS) for providing at least Category II and Category IV views.

[0028] Figure 1B This is a schematic top view of a commercial truck equipped with a camera sight system that provides views of categories II, IV, V, VI, and VIII.

[0029] Figure 2 This is a schematic diagram of the interior of the vehicle's driver's cab.

[0030] Figure 3 The diagram schematically illustrates a rear-view alternative display scene that includes a projected trailer trajectory.

[0031] Figure 4 It shows the use for Figure 3 The method shown demonstrates how to create a rear view trajectory overlay.

[0032] Figure 5 A method for generating alerts based on the projected trajectory is shown.

[0033] The embodiments, examples, and alternatives described in the foregoing paragraphs, claims, or the following description and drawings, including any of their aspects or corresponding individual features, may be understood independently or in any combination. Features described in conjunction with one embodiment apply to all embodiments unless those features are incompatible. Detailed Implementation

[0034] exist Figure 1A and Figure 1B A schematic diagram of a commercial vehicle 10 is shown in the figure. Figure 2 This is a schematic top perspective view of the vehicle compartment 10, including a display. Vehicle 10 includes a vehicle cab or tractor unit 12 for towing a trailer 14. It should be understood that the vehicle cab 12 and / or trailer 14 can be of any configuration (e.g., different types or numbers of trailers). Although commercial trucks are contemplated in this disclosure, the invention can also be applied to other types of vehicles.

[0035] Vehicle 10 includes a Camera Monitoring System (CMS) 15 ( Figure 2 The system includes a driver-side camera arm 16a and a passenger-side camera arm 16b (collectively, “16”) mounted externally to the vehicle cab 12. If desired, the camera arms 16a and 16b may also include conventional viewing mirrors integrated therewith, but the CMS 15 can be used to completely replace the viewing mirrors. In another example, each side may include multiple camera arms and / or each arm housing may include one or more cameras and / or viewing mirrors.

[0036] Each of the camera arms 16a, 16b includes a base that is fixed to, for example, the cab 12. The pivoting arms are supported by the base and can be articulated relative to the base. If desired, the camera arms 16 can instead be fixed. At least one rear-facing camera 20a, 20b (collectively "20") is arranged within each camera arm 16, respectively. The exterior cameras 20a, 20b provide captured images of an exterior field of view FOV EX1 , FOV EX2 , each of which includes at least one of a Class II (narrow) and Class IV (wide) view Figure 1B , which are types of legally mandated views in the commercial trucking industry. If desired, multiple cameras can also be used in each camera arm 16a, 16b to provide these views. For example, the Class II and Class IV views are defined in the European R46 regulation, and the United States and other countries have similar driver visibility requirements for commercial trucks. Certain views can be specified in SAE J3155 or other regulations, for example. Any reference to "class" views is not intended to be limiting, but rather as an example of the type of view provided by a particular camera to a display. Each arm 16a, 16b can also provide a housing that encloses electronics configured to provide various features of the CMS 15.

[0037] First and second video displays 18a, 18b (collectively "18") are arranged on each of the driver and passenger sides within the vehicle cab 12 on or near the A-pillars 19a, 19b to display streaming video of captured images of Class II and Class IV views from the rearward side views captured by the exterior cameras 20a, 20b on their respective side of the vehicle 10.

[0038] If video of Class V and / or VI views is also desired, a camera housing 16c and camera 20c can be arranged at or near the front of the vehicle 10 to provide those views Figure 1B . In one example, the camera 20c is incorporated into one of the plurality of camera arms 16 (e.g., the camera arm on the side opposite the vehicle operator). A third display 18c arranged within the cab 12 near the top center of the windshield can be used to display Class V and VI views toward the front of the vehicle 10 to the driver. The locations, sizes, and fields of the views streamed to any particular display can differ from the configurations described in this disclosure and still incorporate the disclosed invention.

[0039] If a Class III view video is desired, the camera housing can be positioned on the sides and rear of vehicle 10 to provide a field of view including some or all of the Class III areas of vehicle 10. As shown, a Class III view includes a view immediately surrounding the trailer and near the rear of the vehicle (including the rear of the trailer). In one example, the view near the rear of the vehicle is provided by a rearward-facing camera 30 mounted on the trailer and positioned at the rear of the vehicle (e.g., in trailer 14). Figure 1B The view can be generated and may include both immediate rearward views and conventional rearward views (e.g., views extending rearward to the horizon, as can be generated by a rearview mirror in a vehicle without a trailer). In such an example, the third display 18c may include one or more boxes displaying a Class VIII view. Alternatively, additional displays may be added near the first, second, and third displays 18a, 18b, 18c, providing a display specifically for providing a Class VIII view.

[0040] Additional displays can also be provided and used by CMS 15, such as displays located in the central console area inside the passenger compartment 24, typically in the center of the lower half of the passenger compartment, for navigation, infotainment, etc. (i.e., auxiliary information displays). For example, the display could be part of the instrument panel (i.e., the main information display) located behind the steering wheel.

[0041] CMS 15 is also configured to use images from cameras 20a, 20b, 30, as well as images from other cameras, ultrasonic sensors, LiDAR, radar, etc., that can be positioned around the vehicle to determine vehicle features, identify objects, and enable driver assistance features such as display overlay and semi-automatic driver assistance systems.

[0042] These features and functions of CMS 15 are used to implement multiple CMS 15 systems that assist in vehicle operation. It should be noted that the controller 28 used in CMS 15 (e.g., processor and memory 29); Figure 2 The controller 28, which communicates with the displays 18 and cameras 20, 30, can be used to implement various functions disclosed in this application. The controller 28 may include one or more discrete units. For example, a centralized architecture may have a common controller arranged throughout the vehicle 10, while a distributed architecture may use controllers, for example, located in each of the displays 18. Furthermore, a portion of the controller 28 may be located in the vehicle 10, while another portion may be located elsewhere, such as in the camera arm 16. In another example, a master-slave display configuration may be used, where one display includes the controller 28, and the other display receives commands from the controller 28.

[0043] In terms of hardware architecture, such a controller can include a processor, memory (e.g., memory), and one or more input and / or output (I / O) device interfaces that are communicatively coupled via a local interface. The local interface can include, for example but not limited to, one or more buses and / or other wired or wireless connections. The local interface can have additional elements, which are omitted for the sake of simplicity, such as controllers, buffers (caches), drivers, repeaters, and receivers, to enable communications. Further, the local interface can include address, control, and / or data connections to enable appropriate communications among the aforementioned components.

[0044] The controller 28 can be a hardware device for executing software, particularly that stored in memory (e.g., the memory 29). The controller 28 can be a customized or off-the-shelf processor, central processing unit (CPU), a co-processor of several processors associated with the controller, a semiconductor-based microprocessor (in the form of a microchip or chip set), or any other device that typically executes software instructions.

[0045] The memory can include any one or a combination of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, VRAM, etc. ) and / or nonvolatile memory elements (e.g., ROM, hard drive, tape, CD-ROM, etc. ). Moreover, the memory can incorporate electronic, magnetic, optical, and / or other types of storage media. The memory can also have a distributed architecture where various components are situated remote from one another, but can be accessed by the processor.

[0046] The software in the memory can include one or more separate programs, each of which comprises an ordered listing of executable instructions for implementing logical functions. A system component that is constructed as software can also be construed as a source program, executable program (object code), script, or any other entity that includes sets of instructions that when executed implement the logical functions. When constructed as a source program, the program is translated via a compiler, assembler, interpreter, or the like, which can or can not be included within the memory.

[0047] The disclosed input and output devices that can be coupled to the system I / O interface can include input devices, such as but not limited to a keyboard, a mouse, a scanner, a microphone, a camera, a mobile device, a proximity device, etc. Moreover, the output devices, such as but not limited to a printer, a display, etc. Finally, the input and output devices can also include devices that communicate both as inputs and as outputs, such as but not limited to a modem (modulator / demodulator; for accessing another device, system, or network), a radio frequency (RF) or other transceiver, a telephone interface, a bridge, a router, etc.

[0048] When the controller 28 is in operation, the processor can be configured to execute software stored within the memory to communicate data to and from the memory, and to generally control operations of the computing device pursuant to the software. The software in the memory is read, possibly in the processor, buffered, and then executed.

[0049] In various examples, the controller 28 includes one or more modules having algorithms, equations, and / or decision managers that receive inputs from sensors and / or stored values. During vehicle operation, the controller 28 can use outputs (e.g., displays 18, speakers, etc.) to communicate information to the driver, fleet operator, or others.

[0050] One disclosed CMS system is a backup assist system that generates a trailer trajectory projection for a backup maneuver of the vehicle 10. Accurately predicting a trailer backup trajectory is particularly difficult. One way to improve accuracy is to use an image-based trailer tracking method where a rear-facing camera “sees” the trailer move and then uses a kinematic model to track trailer motion. One such method is described in PCT / US2023 / 079589, filed November 14, 2023, entitled “TRAILER BACKUP TRAJECTORY OVERLAY USING TRAILER CAMERA DISPLAY SYSTEM.” However, during a backup maneuver of a commercial truck, the operator must typically stop the vehicle entirely during which time the operator can make additional trailer path adjustments via the steering wheel. There is no trailer motion to track when the vehicle is stopped, but determining a trailer trajectory based on steering wheel input can also be unreliable. To address these competing issues, the disclosed method of determining a trailer trajectory uses an image-based trailer motion method, but modifies the trailer trajectory based on steering angle changes when the image-based trailer motion method is not valid.

[0051] The trailer trajectory can be used by the CMS 15 for various purposes. For example, the trailer trajectory can be used to depict an overlay of the projected trailer path on one of the displays and / or to predict and avoid potential collisions between the trailer and objects. In Figure 3 An example display output to one of the displays of the CMS system 15 is shown in a rear view scene 100. While the illustrated scene 100 includes a single person 120 and a single tree 130 for ease of description, it should be understood that in actual examples, the scene 100 can include more objects, more varied objects, roads, multiple classes of objects, etc. In the illustrated example, the scene 100 includes at least a portion of the rear end of the trailer 14. The scene 100 is displayed on one or more of the monitors 18a, 18b, 18c and / or another monitor within the vehicle.

[0052] During reverse maneuvering, the CMS 15 determines a projected rear trajectory (i.e., an expected path of the rear end of the trailer 14 and / or a trailer wheel path) and provides the projected trajectory as an overlay 110 on top of the scene 100. The overlay 110 extends from the rear end of the trailer 14 into the scene 100 and tracks the expected position of the rear end of the trailer 14 over time and / or distance. For example, when the projected trailer trajectory intersects an object (e.g., the person 120), the CMS 15 can generate an alert indicating that a potential collision can occur. The alert takes the form of audio output to the operator, a shadow identifier 122 in the overlay 110, a color change, or any combination thereof. In other examples, any other method of directing the operator’s attention to the object 120 can be utilized.

[0053] Continuing to refer to the scene 100 of Figure 3 FIG. 1, Figure 4 A process 300 for generating the overlay 110 related to the trailer trajectory is shown schematically. Initially, the CMS 15 receives images from the rear-facing cameras 20a, 20b and / or 30, from the class II / IV cameras, and other cameras in the CMS 15. The CMS 15 then uses image analysis techniques to determine the trailer position, for example, by identifying at least one of the trailer wheel and trailer end position in three-dimensional (real-world) space from the captured images. The trailer angle relative to the tractor 12 at the hitch point is also determined from this image analysis technique in the “determine trailer end position and angle” step 310. In one example, the trailer angle and end position are determined using image analysis only, without using an angle sensor or other sensors in addition to the image sensors (cameras) and captured images of the CMS 15. Further, during this step, the CMS 15 receives a plurality of parameters from the vehicle controller, including truck speed, yaw rate, steering angle, gear, and other camera-external parameters from the vehicle’s CAN bus and / or other sources.

[0054] When vehicle 10 is operating, the trailer end position and angle are computed from images multiple times, and the rate of change of trailer angle and trailer position is determined in an "estimate trailer angle rate of change" step 320. The rate of change is over an interval that can be over time, over distance, or a combination of both. Steps 310, 320 together comprise a method 305 for determining a trailer trajectory based on trailer motion images. In one example, the rate of change of trailer position is determined by applying a Kalman filter to the determined trailer position and trailer angle and additional parameters received from the vehicle controller, where the output of the Kalman filter is the rate of change. The rate of change tracks the change in position of the trailer in 3D space, and is re-determined in each iteration of process 300. In one example, the trailer angular rate and truck speed are converted to trailer position in two perpendicular (x and y) directions. An integration formula computes the change in position of the trailer end over a period of time (e.g., 1 second, 2 seconds, etc.). By predicting the trailer position over the computed time period, a trajectory is obtained by connecting the points.

[0055] Once the rate of change of trailer position is determined, CMS 15 computes the estimated position of the trailer in three-dimensional space at a given time and / or distance interval in a "compute trailer end position" step 330. Process 300 loops step 330 (at 335) multiple times, each loop determining an estimated end position at a different time and / or distance interval. In some examples, the time and / or distance interval is a fixed interval stored in the memory of CMS 15. In alternative examples, the time and / or distance interval can depend on speed, yaw rate, or any other parameter.

[0056] After determining the trailer position at each interval, process 300 combines the trailer positions to create a projected trajectory of the trailer end in a "determine trailer trajectory in 3D space" step 340. The trailer trajectory is the path that the trailer is expected to travel in three-dimensional space as the trailer end travels from each determined interval to the next determined interval (e.g., the trailer end and / or trailer wheels).

[0057] In one example, the complete trajectory of trailer positions connecting each determined interval is determined using a least squares filter on the trailer end points at each interval, and the resulting curve is the predicted trajectory.

[0058] After determining the 3D trajectory of the trailer end, the 3D trajectory is converted to a two-dimensional graphical overlay in a "convert 3D trajectory to 2D overlay" step 350. This conversion converts the three-dimensional trailer end path to a two-dimensional track through scene 100, and creates a transparent overlay 110 of the track.

[0059] Once transparent overlay 110 is created, overlay 110 is applied to the images and displayed to the operator in an "apply 2D overlay to rearview display" step 360.

[0060] The above method does not account for situations where the trailer position cannot be accurately tracked using image analysis, such as when the trailer 14 is moving below a threshold speed (e.g., less than 2 miles per hour (mph)). This is especially true when the vehicle is stopped (0 mph) and the trailer angle rate of change is also zero. In this case, the trailer trajectory correction method 345 is used.

[0061] When a zero or near-zero vehicle speed is determined (step 347), the trailer trajectory is corrected (step 348), the operator’s steering angle change is determined, and a kinematic model is used to predict the trailer trajectory rather than looking at and “seeing” the trailer position based on the captured images. The trailer trajectory overlay is then modified based on the steering change. Once the trailer is moving again such that the method 305 based on trailer motion images is accurate enough, reference to the steering angle change is not needed, but can be in the case of a sudden steering angle change by the driver.

[0062] In one example, the disclosed method displays the overlay of the trailer trajectory on a displayed captured image from one of the rear-facing cameras (e.g., cameras 20a, 20b, and / or 30) (e.g., on displays 18a, 18a, 18c, etc.). The displayed captured image can be different from the captured image used to identify the trailer position, or it can be the same captured image. The displayed captured image can be part of an overhead view, a trailer rear view, or some other display view to visually communicate with the operator (e.g., to show the operator that the trailer is about to hit an object 120, 130 in the scene 100). Figure 3 In one example, the disclosed method displays the overlay of the trailer trajectory on a displayed captured image from one of the rear-facing cameras (e.g., cameras 20a, 20b, and / or 30) (e.g., on displays 18a, 18a, 18c, etc.). The displayed captured image can be different from the captured image used to identify the trailer position, or it can be the same captured image. The displayed captured image can be part of an overhead view, a trailer rear view, or some other display view to visually communicate with the operator (e.g., to show the operator that the trailer is about to hit an object 120, 130 in the scene 100).

[0063] In some examples, after determining the trajectory and before applying the overlay to the scene 100, the CMS 15 identifies any objects 120, 130 in the scene 100 that will intersect with the trajectory and outputs a warning to the vehicle operator. The warning can take the form of an audio output, a visual indicator (as in the example scene 110), a color change, or any similar alert. Figure 5 A method 400 for implementing this alert is shown.

[0064] Initially, the CMS 15, in a “identify objects in view” step 410, uses image-based object recognition techniques to identify the objects 120, 130 in the scene 100 and identifies the two-dimensional locations of the objects 120, 130 in the scene 100. The two-dimensional locations of the objects 120, 130 within the scene 110 are then converted to three-dimensional locations of the objects 120, 130 in real space. After determining the three-dimensional trajectory of the end of the trailer 14, the CMS 15, in a “compare object locations to trajectory” step 420, compares the three-dimensional location of each object to the trajectory and, in a “generate display alert” step 430, indicates an alert when the end of the trailer 14 passes through the same three-dimensional space as the objects 120, 130.

[0065] In more complex systems, a similar trajectory estimation process can be used to estimate the trajectory of a moving object (e.g., person 120) and compare the projected trajectory of the moving object to the projected trajectory of the end of trailer 14. In such examples, an alert is generated when the trajectory of the object interacts with the trajectory of trailer 14 at the same time or within a predefined time span (e.g., within a range of 0 to 10 seconds).

[0066] The disclosed method captures the dynamics of steering wheel changes, enables trailer trajectory prediction at zero vehicle speed, which provides better accuracy at large trailer angular velocities during severe maneuvers. Thus, the disclosed method introduces a complete picture of capturing trailer angle changes, so long-term predictions remain accurate.

[0067] While example implementations have been disclosed, one of ordinary skill in the art will recognize that certain modifications can come within the scope of the claims. Therefore, it is meant to include all such modifications within the scope of the claims.

Claims

1. A method of determining a trailer trajectory of a trailer, comprising the steps of: a) while the trailer is moving: al) determining a trailer position based on at least one captured image; a2) determining a trailer rate of angle change based on the at least one captured image; a3) determining a trailer trajectory based on the trailer position and the trailer rate of angle change; a4) displaying an overlay related to the trailer trajectory; b) while the trailer is below a threshold speed: bl) determining a steering change; b2) revising the trailer trajectory based on the steering change; and b3) displaying a revised overlay related to the trailer trajectory based on the steering change.

2. The method of claim 1, wherein steps a) and b) are performed while the trailer is backing up.

3. The method of claim 1, wherein step al) is performed by identifying at least one of a trailer wheel and a trailer end.

4. The method of claim 3, wherein step a2) is performed by determining a trailer angle, a change in the trailer angle over an interval, and a change in the trailer position over the interval.

5. The method of claim 4, wherein, The interval is at least one of a time and a distance.

6. The method of claim 4, wherein step a3) is performed using the trailer position over the interval.

7. The method of claim 1, wherein steps a4) and b3) are performed by displaying an overlay of the trailer trajectory on a displayed captured image.

8. The method of claim 7, wherein the displayed captured image is different than the at least one captured image.

9. The method of claim 8, wherein the displayed captured image is a portion of an overhead view or a trailer rear view.

10. The method of claim 7, wherein the displayed captured image is the same as the at least one captured image.

11. The method of claim 1, wherein the threshold speed is 2 miles per hour.

12. The method of claim 1, wherein the threshold speed is zero miles per hour.

13. The method of claim 12, wherein the trailer rate of angle change is zero.

14. The method of claim 1, wherein step bl) is performed by obtaining a steering angle from a CAN bus.

15. A camera monitoring system (CMS) for a vehicle, comprising: at least one rear-facing camera configured to obtain at least one captured image; at least one display configured to depict the at least one captured image; a CMS controller, the CMS controller comprising a memory and a processor, the CMS controller in communication with the at least one rear-facing camera and the at least one display, wherein the memory stores instructions for causing the processor to: a) while a trailer is moving: al) determine a trailer position based on the at least one captured image; a2) determine a trailer rate of angle change based on the at least one captured image; a3) determine a trailer trajectory based on the trailer position and the trailer rate of angle change; a4) display an overlay related to the trailer trajectory on one of the at least one display; b) when the trailer is below a threshold speed: b1) determining a steering change; b2) modifying the trailer trajectory based on the steering change; and b3) displaying a modified overlay related to the trailer trajectory based on the steering change.

16. The CMS of claim 15, wherein steps a) and b) are performed when the trailer is backing up, and wherein step b1) is performed by obtaining a steering angle from a CAN bus.

17. The CMS of claim 15, wherein step al) is performed by identifying at least one of a trailer wheel and a trailer end, wherein step a2) is performed by determining a trailer angle, a change in the trailer angle over an interval, and a change in the trailer position over the interval, wherein step a3) is performed using the trailer position over the interval.

18. The CMS of claim 15, wherein steps a4) and b3) are performed by displaying an overlay of the trailer trajectory on a displayed captured image.

19. The CMS of claim 15, wherein the threshold speed is 2 miles per hour.

20. The CMS of claim 15, wherein the threshold speed is zero miles per hour, wherein the trailer angle rate of change is zero.

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