초록 ▼

A vehicle wheel alignment system utilizing one or more optical imaging sensors to acquire either images gradient brightness optical targets affixed to vehicle wheels, or direct images, of the vehicle wheels, from which three-dimensional information related to one or more vehicle wheel alignment angl

A vehicle wheel alignment system utilizing one or more optical imaging sensors to acquire either images gradient brightness optical targets affixed to vehicle wheels, or direct images, of the vehicle wheels, from which three-dimensional information related to one or more vehicle wheel alignment angles can be obtained.

대표청구항 ▼

1. A vehicle wheel alignment apparatus for determining the alignment of one or more wheels of a vehicle, said apparatus comprising:at least one optical target adapted to provide images functionally related to vehicle wheel alignment parameters, said at least one optical target having at least one br

1. A vehicle wheel alignment apparatus for determining the alignment of one or more wheels of a vehicle, said apparatus comprising:at least one optical target adapted to provide images functionally related to vehicle wheel alignment parameters, said at least one optical target having at least one brightness gradient disposed on at least one target face, said brightness gradient including three or more regions, each having a discrete brightness characteristic; at least one camera disposed to generate at least one image of said at least one optical target, said camera configured with an imaging device sensitive to detect said at least one brightness gradient; and a computer operatively connected to said at least one camera, said computer configured to receive and process said at least one image of said optical target to determine one or more optical target parameters; and said computer configured to utilize said one or more optical target parameters to calculate one or more vehicle wheel alignment angles. 2. The vehicle wheel alignment apparatus of claim 1 wherein said at least one brightness gradient is a conical-fit brightness gradient, and wherein a gradient direction established by said regions defines at least one control point.3. The vehicle wheel alignment apparatus of claim 1 wherein said optical target includes a plurality of brightness gradients; and wherein adjacent brightness gradients disposed on said target face each have a common edge, and each have an equal brightness at any point along said common edge.4. The vehicle wheel alignment apparatus of claim 3 wherein a plurality of said common edges intersect to define at least one control point disposed on said target face.5. The vehicle wheel alignment apparatus of claim 3 wherein at least one optical target includes at least a first brightness gradient, a second brightness gradient, and a third brightness gradient, each of said first, second, and third brightness gradients having two common edges.6. The vehicle wheel alignment apparatus of claim 3 wherein at least one optical target includes at least a first brightness gradient, a second brightness gradient, a third brightness gradient, and a fourth brightness gradient, each of said first, second, third, and fourth brightness gradients having at least two common edges.7. A method of determining the alignment of a wheel of a vehicle, comprising the steps of:mounting a known optical target to the wheel on the vehicle, said known optical target having at least one set of three or more brightness gradients disposed on a target surface, each of said brightness gradients in said set having a discrete gradient direction and at least one common edge with an adjacent brightness gradient, said brightness gradients disposed such that each of said common edges intersects at least one additional common edge to define one or more control points on said optical target; obtaining at least one image of said optical target in which at least a portion of said target surface is included; estimating from said image of said optical target a plurality of control lines in said image corresponding to said common edges of said adjacent brightness gradients; calculating intersection points for each of said estimated control lines in said image, said calculated intersection points representative of said one or more control points on said optical target; and determining from said calculated intersection points the alignment of said wheel. 8. The method of claim 7 further including the steps of:calculating a location for one or more centroid points on said optical target surface; and comparing said calculated location with said one or more control points. 9. A method of determining the alignment of a wheel of a vehicle, comprising the steps of:mounting a known optical target to the wheel on the vehicle, said known optical target having one or more brightness gradients disposed on a target surface, each of said brightness gradients having a radial gradient direction defined by two or more concentric regions of brightness characteristics, and configured to provide a center point on said optical target; obtaining at least one image of said optical target in which at least a portion of said target surface is included; estimating from said image of said optical target a plurality of control points in said image, each of said estimated control points corresponding to at least one of said center points; and determining from said estimated control points the alignment of said wheel. 10. The method of claim 9 further including the steps of:calculating a location for one or more centroid points on said optical target surface; and comparing said calculated location with said one or more control points. 11. An improved vehicle wheel alignment system optical target having a base, a face secured to the base, and a mounting structure associated with the base configured to removably secure the target to a vehicle wheel adaptor, the improvement comprising:at least one brightness gradient disposed on the target face, said brightness gradient configured to establish a discrete gradient direction and wherein said brightness gradient establishes at least one target control point. 12. The improved vehicle wheel alignment system optical target of claim 11 further including three or more brightness gradients, each of said brightness gradients having a discrete gradient direction and having at least one common edge with an adjacent brightness gradient;wherein each common edge defines a control line; and wherein each of said defined control lines intersects at least one additional defined control line at one of said at least one said target control points. 13. The improved vehicle wheel alignment system optical target of claim 11 wherein said at least one brightness gradient has a radial brightness gradient direction defining a center point; andwherein said center point corresponds to said at least one target control point. 14. The improved vehicle wheel alignment system optical target of claim 11 wherein said at least one brightness gradient has a centroid, said centroid corresponding to said at least one target control point.15. The vehicle wheel alignment apparatus of claim 7 further including at least one target disposed on said at least one wheel, and wherein said at least one optical time-of-flight sensor is configured to obtain data representative of a distance between said imaging element and at least one point on said at least one target.16. The vehicle wheel alignment system of claim 15 wherein said at least one target has a three-dimensional shape configured to provide a plurality of asymmetrical distance data points to said at least one optical time-of-flight sensor.17. The vehicle wheel alignment system of claim 15 wherein said at least one target optically contrasts with said vehicle wheel.18. A vehicle wheel alignment apparatus for determining the alignment of at least one wheel of a vehicle, said apparatus comprising:at least one imaging component disposed to receive at least one image of said at least one wheel, said imaging component configured with an imaging element adapted to obtain an optical image of said at least one wheel; wherein said at least one imaging component is further configured to obtain data representative of a distance between said imaging element and at least one point on said at least one wheel; a computer operatively connected to said at least one imaging component, said computer configured to process said at least one image together with said obtained distance data to determine one or more wheel alignment measurements; and a plurality of targets secured to said at least one wheel, and wherein said at least one imaging component is configured to obtain data representative of distances between said imaging element and at least one point on each of said plurality of targets. 19. The vehicle wheel alignment system of claim 18 wherein at least a portion of said plurality of targets are three-dimensional features of said at least one wheel.20. The vehicle wheel alignment system of claim 18 wherein at least a portion of said plurality of targets are three-dimensional target elements removably secured to said at least one wheel.21. The vehicle wheel alignment system of claim 15 wherein said imaging element is composed of a plurality of light-detecting pixels; and, said optical time-of-flight sensor includes, for each of said plurality of light-detecting pixels, associated elements adapted to obtain time-of-flight data, each of said associated elements providing a measure of distance from said associated light-detecting pixel to an object in a field of view.22. A vehicle wheel alignment apparatus for determining the alignment of at least one wheel of a vehicle, said apparatus comprising:at least one optical time-of-flight sensor disposed to receive at least one image of said at least one wheel, said optical time-of-flight sensor configured with an imaging element adapted to obtain an optical image of said at least one wheel; wherein said at least one optical time-of-flight sensor is further configured to obtain data representative of a distance between said imaging element and at least one point on said at least one wheel; and a computer operatively connected to said at least one optical time-of-flight sensor, said computer configured to process said at least one image together with said obtained distance data to determine one or more wheel alignment measurements. 23. A vehicle wheel alignment apparatus for determining the alignment of at least one wheel of a vehicle, said apparatus comprising:an optical imaging system configured to obtain at least one image associated with each wheel of a vehicle; a processing system configured to process each of said images to identify a plurality of local features associated with each vehicle wheel; and said processing system further configured to utilize said plurality of identified local features to determine one or more vehicle wheel alignment angles; and wherein each of said plurality of local features is a random local feature disposed on a surface of said associated vehicle wheel. 24. A vehicle wheel alignment apparatus for determining the alignment of at least one wheel of a vehicle, said apparatus comprising:an optical imaging system configured to obtain at least one image associated with each wheel of a vehicle; a processing system configured to process each of said images to identify a plurality of local features associated with each vehicle wheel; and said processing system further configured to utilize said plurality of identified local features to determine one or more vehicle wheel alignment angles; wherein said processing system is further configured to utilize a predetermined minimum number of said identified local features to determine said one or more vehicle wheel alignment angles; and wherein said processing system is configured to signal if said predetermined minimum number of local features is not identified in one or more of said images. 25. A vehicle wheel alignment apparatus for determining the alignment of at least one wheel of a vehicle, said apparatus comprising:an optical imaging system configured to obtain at least one image associated with each wheel of a vehicle; a processing system configured to process each of said images to identify a plurality of local features associated with each vehicle wheel; and said processing system further configured to utilize said plurality of identified local features to determine one or more vehicle wheel alignment angles; and wherein said processing system is configured to identify each of said local features as a three-dimensional local feature. 26. The vehicle wheel alignment apparatus of claim 25 wherein said processing system is configured to identify each of said local features by at least a two-dimensional position and brightness.27. The vehicle wheel alignment apparatus of claim 25 wherein said processing system is configured to identify each of said local features by at least a two-dimensional position and a distance value.28. The vehicle wheel alignment apparatus of claim 23 wherein said processing system is configured to utilize spatial relationships between said plurality of identified local features in each of said images to determine one or more vehicle wheel alignment angles.29. The vehicle wheel alignment apparatus of claim 23 wherein said processing system is configured to identify, from a single image associated with each wheel, said plurality of local features associated with said vehicle wheel.30. A method for determining the alignment of a vehicle, comprising:obtaining a first image of each wheel of the vehicle in a first position and orientation; processing each of said images to identify a plurality of local features associated with each vehicle wheel; moving each of said vehicle wheels; obtaining at least one subsequent image associated with each wheel of a vehicle; processing each of said at least one subsequent image to identify said plurality of local features associated with each vehicle wheel; and utilizing said plurality of identified local features identified in each image to determine one or more vehicle wheel alignment angles. 31. The method of claim 30 for determining the alignment of a vehicle, further including the step of calculating a set of identified reference points for each vehicle wheel from said plurality of identified local features.32. The method of claim 30 for determining the alignment of a vehicle wherein the step of utilizing includes determining positional changes of said identified local features between subsequent images to determine one or more vehicle wheel alignment angles.33. The method of claim 32 for determining the alignment of a vehicle wherein the step of utilizing further includes determining an axis of rotation for each vehicle wheel from said determined positional changes.34. The method of claim 32 for determining the alignment of a vehicle further including the step of establishing a coordinate system for each vehicle wheel from said first image of each vehicle wheel and from a selected subset of said plurality of local features, such that each of said plurality of local features has a fixed position within said established coordinate system.35. The method of claim 34 for determining the alignment of a vehicle further including the step of calculating transformations between each of said established coordinate systems and an associated imaging system coordinate system to determine positional changes in said associated imaging system coordinate system of said identified local features between subsequent images.36. The method of claim 30 for determining the alignment of a vehicle wherein the step of utilizing requires a predetermined minimum number of said identified local features to determine said one or more vehicle wheel alignment angles; and further including the step of providing a signal if said predetermined minimum number of local features is not identified in one or more of said images.37. A method for measuring at least one vehicle wheel alignment angle using a non-contact imaging sensor, comprising:obtaining an initial image of at least a portion of at least one vehicle wheel; processing said initial image to identify a plurality of random features disposed on a surface of said at least one vehicle wheel; and determining if said processed initial image contains at least minimum information required for measuring at least one vehicle wheel alignment angle. 38. The method of claim 37 for measuring at least one vehicle wheel alignment angle wherein said determining step comprises:determining if a minimum number of said plurality of random features are identifiable in said processed initial image. 39. The method of claim 37 for measuring at least one vehicle wheel alignment angle further including, responsive to said processed initial image failing to contain at least said minimum information required, the step of disposing at least one target element on said at least one vehicle wheel.40. A vehicle wheel alignment apparatus for determining the alignment of at least one wheel of a vehicle, said apparatus comprising:an optical imaging system configured to obtain one or more images of a vehicle undergoing alignment, each of said one or more images including at least a portion of a vehicle wheel; a processing system configured to identify, in each of said one or more images, each of said vehicle wheel portions; said processing system configured to locate a plurality of local features associated with a vehicle wheel in each of said images of each of said vehicle wheel portions; said processing system configured to determine an acceptability of each of said images to identify one or more vehicle wheel alignment angles for each of said vehicle wheels; wherein said plurality of local features associated with said vehicle wheel are each disposed on an optical target surface having a predetermined planar characteristic; and wherein said processing system is configured to utilize range information for each of said plurality of local features to identify one or more range measurements varying from said predetermined planar characteristic by at least a predetermined amount, indicative of a bent or damaged optical target, to determine an acceptability of each of said images to identify one or more vehicle wheel alignment angles for each of said vehicle wheels. 41. The vehicle wheel alignment apparatus of claim 1 wherein said discrete brightness characteristics vary uniformly between each of said regions.42. The method of claim 7 wherein the step of estimating said plurality of control lines in said image includes identifying transition points between adjacent discrete gradient directions.43. The method of claim 9 wherein a brightness of each of said brightness gradients varies uniformly in said radial gradient direction.