TRAILER TRACKING APPARATUS AND METHOD

Abstract

The present disclosure relates to a trailer tracking apparatus (2) for monitoring movement of a trailer (3) connected to a vehicle (1). The trailer tracking apparatus (2) has a controller (5) comprising an electronic processor (6) having an electrical input for receiving image data (DAT) from an imaging sensor (10) disposed on the vehicle (1). An electronic memory device (7) having instructions stored therein is electrically coupled to the electronic processor (6). The electronic processor (6) is configured to access the memory device (7) and to execute the instructions stored therein. The electronic processor (6) is operable to select a subset of said image data (DAT.sub.SUB1). One or more element (16) are detected and monitored within the selected subset (DAT.sub.SUB1) of said image data (DAT). The electronic processor (6) determines movement of the trailer (3) relative to the vehicle (1) in dependence on evolution of said one or more detected element (16) with respect to time. The present disclosure also relates to a method of tracking a trailer (3); and to a vehicle (1) incorporating the trailer tracking apparatus (2).

Claims

1. A trailer tracking apparatus for monitoring movement of a trailer connected to a vehicle, the trailer tracking apparatus comprising: a controller comprising an electronic processor having an electrical input for receiving image data from an imaging sensor disposed on the vehicle; and an electronic memory device electrically coupled to the electronic processor and having instructions stored therein; wherein the electronic processor is configured to access the memory device and execute the instructions stored therein such that it is operable to: select a subset of the image data; detect and monitor one or more elements within the selected subset of the image data; and determine movement of the trailer relative to the vehicle in dependence on evolution of the one or more detected elements with respect to time.

2. The trailer tracking apparatus as claimed in claim 1, wherein the electronic processor is configured to characterize each of the one or more detected elements as a persistent element or a transient element.

3. The trailer tracking apparatus as claimed in claim 2, wherein the electronic processor is configured to determine movement of the trailer in dependence on evolution of each persistent element.

4. The trailer tracking apparatus as claimed in claim 2, wherein the electronic processor is further configured to: modify the selected subset of the image data to include image data representing one or more persistent elements, and/or modify the selected subset of the image data to exclude each transient element.

5. (canceled)

6. The trailer tracking apparatus as claimed in claim 1, wherein the evolution of the one or more detected elements comprises one or more of the following: acceleration, velocity, angular velocity, angular acceleration, movement, size, shape and orientation.

7. The trailer tracking apparatus as claimed in claim 1, wherein the electronic processor is configured to receive a user input to select the subset of the image data.

8. The trailer tracking apparatus as claimed in claim 1, wherein the electronic processor is configured to select the subset of the image data.

9. A trailer tracking apparatus for monitoring movement of a trailer connected to a vehicle, the trailer tracking apparatus comprising: a controller comprising an electronic processor having an electrical input for receiving image data from an imaging sensor disposed on the vehicle; and an electronic memory device electrically coupled to the electronic processor and having instructions stored therein; wherein the electronic processor is configured to access the memory device and execute the instructions stored therein such that it is operable to: detect one or more elements within the image data; monitor the one or more elements and characterize each of the one or more elements as a persistent element or a transient element; and determine movement of the trailer relative to the vehicle in dependence on the evolution of each persistent element with respect to time.

10. A vehicle comprising a trailer tracking apparatus as claimed in claim 1.

11-22. (canceled)

23. The trailer tracking apparatus as claimed in claim 9, wherein the evolution of each persistent element comprises a movement trajectory including direction and magnitude, wherein the movement trajectory is used to track the movement of the trailer.

24. The trailer tracking apparatus as claimed in claim 23, wherein the electronic processor is further configured to compare relative movement trajectories of several of the persistent elements.

25. A vehicle comprising the trailer tracking apparatus as claimed in claim 9.

26. A method of monitoring movement of a trailer connected to a vehicle, the method comprising: receiving image data from an imaging sensor; detecting one or more elements within the image data; characterizing each of the one or more elements as a persistent element or a transient element; and determining movement of the trailer relative to the vehicle in dependence on evolution of each persistent element with respect to time.

27. The method as claimed in claim 26, further comprising: selecting a subset of the image data; and detecting and monitoring the one or more elements within the selected subset of the image data.

28. The method as claimed in claim 27, further comprising: modifying the selected subset of the image data to include image data representing one or more persistent elements; and/or modifying the selected subset of the image data to exclude each transient element.

29. The method as claimed in claim 26, wherein the evolution of each persistent element comprises one or more of the following: acceleration, velocity, angular velocity, angular acceleration, movement, size, shape and orientation.

30. The method as claimed in claim 26, wherein the evolution of each persistent element comprises a movement trajectory including direction and magnitude, wherein the movement trajectory is used to track the movement of the trailer.

31. The method as claimed in claim 30, further comprising comparing relative movement trajectories of several of the persistent elements.

32. The method as claimed in 26, further comprising selecting the subset of the image data in dependence on a user input.

33. The method as claimed in claim 26, further comprising automatically selecting the subset of the image data.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] One or more embodiments of the present invention will now be described, by way of example only, with reference to the accompanying figures, in which:

[0025] FIG. 1 shows a schematic representation of a vehicle having a trailer tracking apparatus in accordance with an embodiment of the present invention;

[0026] FIG. 2 shows a schematic representation of the vehicle and the trailer tracking apparatus shown in FIG. 1; and

[0027] FIG. 3 illustrates processing of the image data by the trailer tracking apparatus in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

[0028] A vehicle 1 incorporating a trailer tracking apparatus 2 in accordance with an embodiment of the present invention will now be described by way of example. The vehicle 1 is connected to a trailer 3, as illustrated in FIG. 1. As described herein, the trailer tracking apparatus 2 is disposed in the vehicle 1 to track movement of the trailer 3.

[0029] The vehicle 1 in the present embodiment is an automobile, but it will be appreciated that the present invention is not limited in this respect. For example, the trailer tracking apparatus 2 could be incorporated into a tractor unit. Furthermore, the trailer 3 in the present embodiment is illustrated as a caravan, but it will be appreciated that the present invention is not limited in this respect. For example, the trailer 3 could be a horse trailer or a box trailer.

[0030] As shown in FIG. 1, the trailer 3 is pivotally connected to a connector 4. The connector for is mounted centrally at the rear of the vehicle 1 coincident with a central original axis X of the vehicle 1. The connector 4 in the present embodiment is in the form of a hitch ball connector which allows the trailer 3 to pivot about a vertical axis Z1. The connector 4 also allows a limited rotational movement of the trailer 3 about a longitudinal axis X1, and a transverse axis Y1. It will be appreciated that the connector 4 could take a variety of forms, for example a towbar ring, a pintle hook, a ball pintle hook, a clevis hitch, a ball and pin towing hitch.

[0031] A schematic representation of the trailer tracking apparatus 2 is shown in FIG. 2. The trailer tracking apparatus 2 comprises a controller 5 having one or more electronic processor 6 (only one is shown for simplicity of explanation) and system memory 7 having computer code 8 stored thereon. As described herein, the electronic processor 6 is operative to implement an image processing module 9 configured to analyse image data DAT received from an imaging sensor 10. The imaging sensor 10 is in the form of an optical camera. The imaging sensor 10 is rearward facing and is arranged such that its field of view includes a front portion 11 of the trailer 3 (when the trailer 3 is connected to the vehicle 1). The imaging sensor 10 is operative to provide a video image to enable changes in the relative position of the trailer 3 to be determined, as described herein. It will be appreciated that the image sensor 10 could provide additional functions, for example as a parking aid for the vehicle 1.

[0032] The imaging sensor 10 transmits the image data DAT to the electronic processor 6 over a vehicle communication network, such as a communication area network (CAN) bus. The image processing module 9 receives the image data DAT and a first subset DAT.sub.SUB1, of the image data DAT is selected for analysis. The first subset DAT.sub.SUB1, corresponds to a portion of the image captured by the imaging sensor 10 and is intended to capture a section of the front portion 11 of the trailer 3. The first subset DAT.sub.SUB1, can be selected automatically, for example corresponding to a predefined region of the image; or can be selected by a user, for example using a human machine interface (HMI) 12. In the present embodiment, the trailer tracking apparatus 2 is configured to receive user inputs via the HMI 12 to select the first subset DAT.sub.SUB1. The HMI 12 comprises a display screen 13 (such as a liquid crystal display) to which the image data DAT is output in the form of an image 14. The user is prompted to select a region of the image 14 which includes at least a portion of the trailer 3 visible in said image 14. The user can, for example, use a touch-screen interface to trace a window 15 within the image 14. The first subset DAT.sub.SUB1, corresponds to the region selected by the user.

[0033] The image processing module 9 implements an image processing algorithm to track movement of the trailer 3. In particular, the image processing module 9 analyses the first subset DAT.sub.SUB1 to identify at least one element 16 which can be tracked with respect to time.

[0034] The analysis of the first subset DAT.sub.SUB1 can comprise applying a mathematical operator to identify said at least one element 16. The mathematical operator can be in the form of a filter, for example a particle filter, suitable for tracking and predicting the movements of active contours and features in the real image. The mathematical operator can thereby estimate the model configuration that at least substantially matches the current observations. In the present embodiment, the image processing module 9 is configured to identify a plurality of said elements 16 each corresponding to a visible feature within the image. The elements 16 can each correspond to one or more pixels defined by the image data DAT. In the context of analysing the image data DAT, each element 16 identified by the image processing module 9 can be referred to as a particle. By analysing the first subset DAT.sub.SUB1, with respect to time, the image processing module 9 can monitor particle evolution. The particle evolution can, for example, be tracked by identifying the particle state S.sub.t in an image scan at time t, and the related state S.sub.t+1, in a subsequent scan at time t+1. By comparing the properties of the states S.sub.t and S.sub.t+1, the image processing module 9 can monitor particle evolution. The particle evolution can, for example, identify one or more of the following: position, size, trajectory and orientation.

[0035] The image processing module 9 is configured to select those elements 16 which are identifiable within the first subset DAT.sub.SUB1, for a time period longer than a predetermined time threshold (or in a series of scanning cycles greater than a predetermined scanning threshold); these elements 16 are referred to herein as persistent elements. The image processing module 9 can also analyse the first subset DAT.sub.SUB1, to identify those elements 16 which are identifiable only for a time period less that the predetermined time threshold (or in a series of scanning cycles less than the predetermined scanning threshold); these elements 16 are referred to herein as transient elements. The image processing module 9 characterises the elements 16 as either persistent elements 16P or transient elements 16T. There is a higher statistical probability that the persistent elements 16P correspond to a feature of the trailer 3 (since they are present for an extended time period and are more likely to form part of the trailer 3 being towed behind the vehicle 1). The transient elements 16T are more likely to represent a feature away from the trailer 3, for example in the scenery or another vehicle, which may be visible only fleetingly or over a short time period. Thus, there is a lower statistical probability that the transient elements 16T correspond to a element forming part of the trailer 3 (since they are present for a relatively short time period). The image processing module 9 can be configured to disregard any transient elements 16T identified in the first subset DAT.sub.SUB1. Further analysis of the first subset DAT.sub.SUB1, can be performed in respect of the persistent elements 16P.

[0036] The image processing module 9 identifies and monitors the persistent elements 16P to track their evolution (progression) with respect to time, for example over a plurality of scan cycles. The evolution of the persistent elements 16P in the present embodiment comprises their movement trajectories (direction and magnitude) which can be used to track the movement of the trailer 3. For example, a vertical or lateral movement of one or more persistent element 16P can correspond respectively to a vertical or lateral movement of the trailer 3. A combination of vertical and lateral movements can indicate a pivoting movement of the trailer 3 about the vertical axis Z.

[0037] The image processing module 9 can determine the spatial location of each persistent element 16P and this can be used to determine the associated movement of the trailer 3. For example, the movement trajectory of each persistent element 16P can be mapped to a reference datum (such as a known spatial position of the connector 4) to identify a pivoting movement of the trailer 3. The image processing module 9 could optionally compare relative movement trajectories of several of said persistent elements 16P identified within the first subset DAT.sub.SUB1.

[0038] Alternatively, or in addition, the evolution of each persistent element 16P can comprise changes in the size of said one or more persistent element 16P. A change in the size of the persistent element 16P can also indicate a pivoting movement of the trailer 3. For example, the size of a persistent element 16P will increase or decrease depending on the direction in which the trailer 3 pivots.

[0039] Alternatively, or in addition, the evolution of each persistent element 16P can comprise changes in the shape and/or orientation of the persistent element 16P. The image processing module 9 could, for example, identify a persistent element 16P having a clearly defined feature (for example corresponding to an edge of a window in the front portion 11 of the trailer 3). The change in the shape and/or orientation of the persistent element 16P could be used to track movement of the trailer 3. The image processing module 9 tracks the trailer 3 and outputs a tracking signal SIG. The tracking signal SIG 1 can be used by other vehicle systems, for example to assist with towing, stability, hitching and manoeuvring.

[0040] If the image processing module 9 is unable to identify any persistent elements 16P within the region of the image 14 selected by the user, a notification can be output to the user. For example, the electronic processor 6 can output a prompt to the user to re-select the region of the image 14 by re-tracing the window 15 on the display screen 13. A second data subset DAT.sub.SUB2 can be selected form the image data DAT in dependence on the re-selected region of the image 14. The image processing module 9 repeats the analysis in respect of said second data subset DAT.sub.SUB2.

[0041] The operation of the image processing module 9 will now be described with reference to FIG. 3. The trailer 3 is connected to the connector 4 in conventional manner. The imaging sensor 10 generates image data DAT which is output to the electronic processor 6. An image 14 corresponding to a field of view FOV of the imaging sensor 10 is also output to the display screen 13. The user uses the HMI 12 to trace the window 15 to select a region of the image 14. The window 15 should be traced to cover at least a portion of the trailer 3 and an on-screen prompt can be displayed to the user. A first data subset DAT.sub.SUB1, is extracted from the image data DAT corresponding to the region selected by the user. The image processing module 9 analyses the first data subset DAT.sub.SUB1, to identify a plurality of elements 16 contained therein. The image processing module 9 analyses the elements 16 and characterises them as either persistent elements 16P or transient elements 16T. The image processing module 9 tracks the persistent elements 16P with respect to time to monitor their evolution. The evolution of the persistent elements 16P can, for example, comprise changes in shape and/or position and/or movement. The evolution of the persistent elements 16P is used to track the movement of the trailer 3 relative to the vehicle 1. The image processing module 9 outputs a tracking signal SIG which can be used by other vehicle systems to facilitate towing of the trailer 3. If the image processing module 9 determines that the first data subset DAT.sub.SUB1, does not contain sufficient persistent elements 16P for reliable analysis, a prompt can be output to request that the user selects an alternate region within the image 14.

[0042] It will be appreciated that various changes and modifications can be made to the trailer tracking apparatus 2 described herein. For example, the electronic processor 6 can be configured automatically to select the first data subset DAT.sub.SUB1, from the image data DAT generated by the imaging sensor 10. Furthermore, the electronic processor 6 can be configured to receive dynamic operating parameters from the communication network which could be used in the analysis of the first data subset DAT.sub.SUB1. The dynamic operating parameters could, for example, comprise one or more of the following: vehicle speed, acceleration and steering angle. The electronic processor 6 could, for example, be configured to select the first data subset DAT.sub.SUB1 from a region of the image data DAT in dependence on the steering angle in order to reduce the likelihood of selecting a portion of the background. Alternatively, or in addition, the image processing module 9 could be configured to analyse the first data subset DAT.sub.SUB1 to identify persistent elements 16P only when the vehicle 1 is moving (i.e. the vehicle speed is greater than 0). Alternatively, or in addition, the image processing module 9 could be configured to correlate movements of each persistent element 16P identified in the image data DAT with the steering angle of the vehicle 1. A further possibility would be to determine one or more characteristics of the trailer 3, for example wheelbase and or length, by comparing the response of the trailer 3 to steering inputs to the vehicle 1.