Trailer alignment detection for dock automation using vision system and dynamic depth filtering

1. A method of determining an alignment of a trailer, the method comprising:

capturing, by a 3D camera system, image data and position data of a field of view, wherein the image data includes a top surface of the trailer at a loading bay;

determining an estimated height of the top surface of the trailer;

determining a dynamic height range based on the estimated height of the top surface of the trailer, wherein the dynamic height range includes a range of vertical positions including the estimated height of the top surface of the trailer;

applying a dynamic depth filter to filter image data corresponding to heights outside of the dynamic height range from the image data captured by the 3D camera system; and

determining, based on the depth-filtered image data, at least one selected from a group consisting of an angular position of the trailer and a lateral offset of the trailer.

2. The method of claim 1 , wherein applying the dynamic depth filter includes

setting a first plurality of pixels to a first color value, wherein the first plurality of pixels includes all pixels in the captured image data corresponding to positions within the defined dynamic height range; and

setting a second plurality of pixels to a second color value, wherein the second plurality of pixels includes all pixels in the captured image data corresponding to positions outside of the defined dynamic height range.

3. The method of claim 2 , further comprising generating a two dimensional binary image, wherein the two-dimensional binary image includes a downward perspective view of the image data captured by the 3D camera with all pixels including either the first color value or the second color value, and wherein all pixels within the two-dimensional binary image set to the first color value represent objects within the dynamic height range and all pixels set to the second color value represent objects outside of the dynamic height range.

4. The method of claim 1 , further comprising estimating a position of an outline of the top surface of the trailer by applying a rectangular approximation to the depth-filtered image data to identify image data corresponding to a rectangular shape of the top surface of the trailer.

5. The method of claim 1 , further comprising estimating a position of an outline of the top surface of the trailer by applying an edge-finding processing to the depth-filtered image data to locate edges corresponding to the outline of the top surface of the trailer.

6. The method of claim 5 , wherein estimating the position of the outline of the top of the trailer further includes determining a location of at least one corner of the top surface of the trailer based on an intersection of two edges detected by the edge-finding processing.

7. The method of claim 1 , further comprising:

estimating a position of an outline of the top surface of the trailer,

wherein the 3D camera system is mounted at a location relative to a docking bay, wherein the top surface of the trailer in the field of view of the 3D camera system includes the top surface of the trailer approaching the docking bay in reverse,

wherein determining the at least one selected from the group consisting of the angular position of the trailer and the lateral offset of the trailer includes

determining, based on the estimated position of the outline of the top surface of the trailer, a centerline of the trailer, and

calculating the angular position of the trailer as an angle of the centerline of the trailer relative to a front edge of the docking bay,

the method further comprising comparing the angular position of the trailer to an angle tolerance threshold, wherein the angle tolerance threshold defines a maximum allowable magnitude of difference between the angular position of the trailer and an angle perpendicular to the front edge of the docking bay.

8. The method of claim 1 , further comprising:

estimating a position of an outline of the top surface of the trailer,

wherein the 3D camera system is mounted at a location relative to a docking bay, wherein the top surface of the trailer in the field of view of the 3D camera system includes the top surface of the trailer approaching the docking bay in reverse,

wherein determining the at least one selected from the group consisting of the angular position of the trailer and the lateral offset of the trailer includes

determining, based on the estimated position of the outline of the top surface of the trailer, a centerline of the trailer, and

calculating the lateral offset as a difference between a center point of a line corresponding to the docking bay and a point at which the centerline of the trailer intersects the line corresponding to the docking bay,

the method further comprising comparing the lateral offset of the trailer to an offset tolerance threshold, wherein the offset tolerance threshold defines a maximum allowable magnitude of the lateral offset.

9. The method of claim 1 , further comprising generating an alarm signal in response to determining that the at least one selected from the group consisting of the angular position of the trailer and the lateral offset of the trailer exceeds a tolerance threshold.

10. The method of claim 1 , further comprising:

generating instructions for adjusting the alignment of the trailer based on the at least one selected from the group consisting of the angular position of the trailer and the lateral offset of the trailer; and

transmitting the instructions to at least one selected from a group consisting of a driver of a vehicle coupled to the trailer and an autonomous driving system of the vehicle coupled to the trailer.

11. The method of claim 1 , further comprising:

detecting a calibration target in the image data captured by the 3D camera system;

determining a position of the calibration target in a 3D coordinate frame of the 3D camera system based on the captured image data and the captured position data; and

determining a location and an orientation of a docking bay in the 3D coordinate frame of the 3D camera system based on the determined position of the calibration target in the 3D coordinate frame of the 3D camera system, wherein the location and the orientation of the docking bay relative to the calibration target is known,

wherein determining the at least one selected from the group consisting of the angular position of the trailer and the lateral offset of the trailer includes

determining the angular position of the trailer relative to the docking bay in the 3D coordinate frame of the 3D camera system, and

determining the lateral offset of the trailer relative to the docking bay in the 3D coordinate frame of the 3D camera system.

12. The method of claim 1 , wherein determining the estimated height of the top surface of the trailer includes calculating an average height of a plurality of image pixels corresponding to the top surface of the trailer.

13. A trailer alignment determination system, the system comprising:

a controller including an electronic processor and a memory, the controller configured to

receive image data and position data captured by a 3D camera system, the position data indicating positions in 3D space of pixels in the image data, wherein the image data includes a top surface of a trailer at a loading bay,

determine an estimated height of the top surface of the trailer,

determine a dynamic height range based on the estimated height of the top surface of the trailer, wherein the dynamic height range includes a range of vertical positions including the estimated height of the top surface of the trailer,

apply a dynamic depth filter to filter image data corresponding to heights outside of the dynamic height range from the image data captured by the 3D camera system, and

determine, based on the depth-filtered image data, at least one selected from a group consisting of an angular position of the trailer and a lateral offset of the trailer.

14. The system of claim 13 , wherein the controller is configured to generate a binary image based on the application of the dynamic depth filter, wherein all image data pixels in the binary image corresponding to positions within the dynamic height range are set to a first color value, and wherein all image data pixels in the binary image corresponding to positions outside of the dynamic height range are set to a second color value.

15. The system of claim 14 , wherein the controller is further configured to estimate a position of an outline of the top surface of the trailer in the captured image data by applying an edge-finding processing to the generated binary image and locating a position of at least one corner of the top surface of the trailer based on an intersection between to edges detected by the edge-finding processing.

16. The system of claim 14 , wherein the controller is further configured to estimate a position of an outline of the top surface of the trailer in the captured image data by applying a rectangular approximation to the generated binary image to identify image data corresponding to a rectangular shape of the top surface of the trailer.

17. The system of claim 13 , further comprising:

a support arm mounted at a location relative to at least one selected from a group consisting of a docking bay and a door; and

a 3D camera system coupled to a distal end of the support arm and positioned with an at least partially downward-facing field of view,

wherein the 3D camera system is coupled to the distal end of the support arm at an angle relative to vertically downward such that a center axis of the field of view of the 3D camera system extends partially downward and partially forward.

18. The system of claim 17 , further comprising an adjustable height mounting bracket, wherein a proximal end of the support arm is adjustably coupled to the adjustable height mounting bracket, and wherein a height of the support arm relative to the adjustable height mounting bracket is selectively adjustable.

19. The system of claim 17 , further comprising a calibration target positioned at a known location and a known orientation relative to the docking bay, wherein the controller is further configured to

detect the calibration target in the image data captured by the 3D camera system;

determine a position of the calibration target in a 3D coordinate frame of the 3D camera system based on the captured image data and the captured position data; and

determine, based on the determined position of the calibration target in the 3D coordinate frame of the 3D camera system, a location and an orientation in the 3D coordinate frame of the at least one selected from the group consisting of the docking bay and the door, and

wherein the controller is configured to determine the at least one selected from the group consisting of the angular position of the trailer and the lateral offset of the trailer by

determining the angular position of the trailer relative to the docking bay in the 3D coordinate frame of the 3D camera system, and

determining the lateral offset of the trailer relative to the docking bay in the 3D coordinate frame of the 3D camera system.

20. A method of determining an alignment of a trailer, the method comprising:

capturing, by a 3D camera system, image data and position data of a field of view, wherein the image data includes a top surface of the trailer;

determining an estimated height of the top surface of the trailer;

determining a dynamic height range based on the estimated height of the top surface of the trailer, wherein the dynamic height range includes a range of vertical positions including the estimated height of the top surface of the trailer;

applying a dynamic depth filter to filter image data corresponding to heights outside of the dynamic height range from the image data captured by the 3D camera system; and

determining, based on the depth-filtered image data, at least one selected from a group consisting of an angular position of the trailer and a lateral offset of the trailer, wherein applying the dynamic depth filter includes

setting a first plurality of pixels to a first color value, wherein the first plurality of pixels includes all pixels in the captured image data corresponding to positions within the defined dynamic height range; and

setting a second plurality of pixels to a second color value, wherein the second plurality of pixels includes all pixels in the captured image data corresponding to positions outside of the defined dynamic height range.