Hitch assist system with trailer height estimation and hitch coupler identification
A system and methods related to hitch assist are provided herein. An imager captures rear-vehicle images. A processor is configured to extract trailer and ground features from the captured images, compute vehicle motion displacement based on optical flow of the ground features, estimate a height of each trailer feature based on vehicle motion displacement and optical flow of the trailer features, and determine a trailer height based on the estimated heights of at least a portion of the trailer features.
1. A hitch assist system comprising:
an imager for capturing rear-vehicle images; and
a processor configured to:
extract trailer and ground features from the captured images;
compute vehicle motion displacement based on optical flow of the ground features;
estimate a height of each trailer feature based on vehicle motion displacement and optical flow of the trailer features; and
determine a trailer height based on the estimated heights of at least a portion of the trailer features.
2. The system of claim 1 , wherein the trailer height corresponds to a height of a hitch coupler of a trailer, and wherein the trailer features are extracted from a region of interest specified by a user.
3. The system of claim 1 , wherein computation of vehicle motion displacement is further based on a known height of the imager.
4. The system of claim 1 , wherein the processor is further configured to classify each trailer feature as on-trailer or off-trailer by thresholding the estimated height thereof.
5. The system of claim 4 , wherein the processor determines the trailer height based on a median estimated height of only the trailer features classified as on-trailer.
6. The system of claim 1 , wherein the processor determines the trailer height based on a median estimated height of all of the trailer features.
7. The system of claim 1 , wherein the processor adds the trailer height to a global histogram.
8. The system of claim 1 , wherein the processor is further configured to generate a top-down view from the captured images and apply a parametric circle function to locate circular structures to detect a hitch coupler of a trailer.
9. The system of claim 8 , wherein the processor applies the parametric circle function to locate circular structures inside a region of interest specified by a user.
10. The system of claim 9 , wherein the processor identifies a circular structure as representing the hitch coupler and applies a filter to the circular structure.
11. The system of claim 10 , wherein the processor centers the region of interest about a center coordinate of the circular structure in a subsequent image frame.
12. A hitch assist system comprising:
an imager for capturing rear-vehicle images; and
a processor configured to:
extract ground features and potential trailer features from the captured images;
compute vehicle motion displacement based on optical flow of the ground features;
estimate a height of each potential trailer feature based on vehicle motion displacement and optical flow of the potential trailer features;
classify the potential trailer features as on-trailer or off-trailer; and
determine a trailer height based on the estimated heights of only the potential trailer features classified as on-trailer.
13. The system of claim 12 , wherein the trailer height corresponds to a height of a hitch coupler of a trailer, and wherein the potential trailer features are extracted from a region of interest specified by a user.
14. The system of claim 12 , wherein computation of vehicle motion displacement is further based on a known height of the imager.
15. The system of claim 12 , wherein the processor adds the trailer height to a global histogram.
16. The system of claim 12 , wherein the processor is further configured to generate a top-down view from the captured images and apply a parametric circle function to locate circular structures to detect a hitch coupler of a trailer.
17. The system of claim 16 , wherein the processor applies the parametric circle function to locate circular structures inside a region of interest specified by a user.
18. The system of claim 17 , wherein the processor identifies a circular structure as representing the hitch coupler and applies a filter to the circular structure.
19. The system of claim 18 , wherein the processor centers the region of interest about a center coordinate of the circular structure in a subsequent image frame.
20. A method of estimating a trailer height, comprising the steps of:
capturing rear-vehicle images;
extracting trailer and ground features from the captured images;
computing vehicle motion displacement based on optical flow of the ground features;
estimating a height of each trailer feature based on vehicle motion displacement and optical flow of the trailer features; and
determining a trailer height based on the estimated heights of at least a portion of the trailer features.