Method and apparatus for wheel alignment

• US 7,953,247 B2
• Filed: 05/21/2007
• Issued: 05/31/2011
• Est. Priority Date: 05/21/2007
• Status: Active Grant

• Current Assignee: Snap-On Incorporated
• Original Assignee: Snap-On Incorporated
• Inventors: Kassouf, Thomas L., Glickman, Stephen L., Jackson, David A.
• Primary Examiner(s): Johns; Andrew W
• Application Number:
  US11/802,245
• Publication Number:
  US 20080289202A1
• Time in Patent Office: 1,471 Days
• Field of Search: 382/100, 382/103, 382/104, 382/154, 356/139.09, 356/155, 332/03, 332/031.8, 332/031.9, 332/032, 332/88
• US Class Current: 382/104
• CPC Class Codes: G01B 11/275 for testing wheel alignment
• CPC Class Codes: G01B 11/2755 using photoelectric detection means
• CPC Class Codes: G01B 2210/143 One or more cameras on each side of a vehicle in the main embodiment
• CPC Class Codes: G01B 2210/26 Algorithms, instructions, databases, computerized methods and graphical user interfaces employed by a user in conjunction with the wheel aligner
• CPC Class Codes: G01B 2210/30 Reference markings, reflector, scale or other passive device
• CPC Class Codes: G01B 2210/306 Mirror, prism or other reflector

Abstract

A vehicle wheel alignment method and system is provided. A three-dimensional target is attached to a vehicle wheel known to be in alignment. The three-dimensional target has multiple target elements thereon, each of which has known geometric characteristics and 3D spatial relationship with one another.

Claims

1. A method for determining the alignment of a motor vehicle wheel, comprising the steps of:

attaching a three-dimensional target on the vehicle wheel, wherein the three-dimensional target comprises a first planar target on a first substrate and a second planar target on a second substrate, the first and second substrates being spaced apart from each other, each of the first and second planar targets having thereon a plurality of target elements having known geometric characteristics and being configured in 3D space in accordance with known three-dimensional relationships with each other;

detecting, from a 2D image of the three-dimensional target acquired by at least one camera, a plurality of target element images corresponding to the plurality of target elements; and

determining the alignment of the wheel based on a spatial orientation of the three-dimensional target determined based on the target element images and the three-dimensional relationships among the target elements.

2. The method according to claim 1, wherein the three dimensional target has a plurality of facets, at least one of which has one or more target elements residing on the surface of the facet.

3. The method according to claim 2, wherein the target elements on a surface of a part forms a prescribed pattern.

4. The method according to claim 2, wherein surfaces of different parts having target elements thereon have certain geometric relationships.

5. The method according to claim 2, wherein the plurality of parts are constructed within a housing for the three-dimensional target.

6. The method according to claim 1, wherein the target elements are made retro-reflective and reside against a non-reflective surface of the three-dimensional target.

7. The method according to claim 1, wherein the target elements are made non-reflective and reside against a retro-reflective surface of the three-dimensional target.

8. The method according to claim 1, wherein the step of determining the alignment comprises the step of detecting an image feature of each target element image.

9. The method according to claim 8, wherein the image feature includes a representative location of the target element image.

10. The method according to claim 9, wherein the representative location corresponds to a centroid of the corresponding target element image.

11. A method for determining the alignment of a motor vehicle wheel, comprising the steps of:

attaching a three-dimensional target on a vehicle, wherein the three-dimensional target comprises a first planar target on a first substrate and a second planar target on a second substrate, the first and second substrates being spaced apart from each other, each of the first and second planar targets having thereon a plurality of target elements having known geometric characteristics and being configured in 3D space in accordance with known three-dimensional relationships with each other;

acquiring a 2D image of the three-dimensional target using at least one camera; and

utilizing the 2D image of the three-dimensional target to determine wheel alignment based on the three-dimensional target.

12. A system for determining the alignment of a motor vehicle wheel, comprising:

a three-dimensional target for attachment to a vehicle wheel, wherein the three-dimensional target comprises a first planar target on a first substrate and a second planar target on a second substrate, the first and second substrates being spaced apart from each other, each of the first and second planar targets having thereon a plurality of target elements having known geometric characteristics and being configured in 3D space in accordance with known three-dimensional relationships with each other;

a 2D imaging system for acquiring a 2D image of the three dimensional target;

a target element feature detecting system for detecting, from the 2D image, a plurality of target element images corresponding to the plurality of target elements; and

a wheel alignment determination system for determining the alignment of the vehicle wheel based on a spatial orientation of the three-dimensional target determined in accordance with the detected target element images and the three-dimensional relationships among the target elements.

13. The system according to claim 12, wherein the three dimensional target has a plurality of parts, at least one of which has one or more target elements residing on a surface of the part.

14. The system according to claim 13, wherein the target elements on a surface of a part forms a prescribed pattern.

15. The system according to claim 13, wherein surfaces of different parts having target elements thereon form certain geometric relationships.

16. The system according to claim 13, wherein the plurality of parts are constructed within a housing for the three-dimensional target.

17. The system according to claim 12, wherein the target elements are made retro-reflective and reside against a non-reflective surface of the three-dimensional target.

18. The system according to claim 12, wherein the target elements are made non-reflective and reside against a retro-reflective surface of the three-dimensional target.

19. A system for determining the alignment of a motor vehicle wheel, comprising:

a three-dimensional target attachable to a wheel to be aligned, wherein the three-dimensional target comprises a first planar target on a first substrate and a second planar target on a second substrate, the first and second substrates being spaced apart from each other, each of the first and second planar targets having thereon a plurality of target elements having known geometric characteristics and being configured in 3D space in accordance with known three-dimensional relationships with each other;

an imaging system, having at least one camera, capable of acquiring a 2D image of the three dimensional target; and

a wheel orientation determination system configured for utilizing the 2D image of the three-dimensional target to determine wheel orientation based on the three-dimensional target.

20. A method for determining a measurement relating to an object, comprising the steps of:

associating a three-dimensional target with the object, wherein the three-dimensional target comprises a first planar target on a first substrate and a second planar target on a second substrate, the first and second substrates being spaced apart from each other, each of the first and second planar targets having thereon a plurality of target elements having known geometric characteristics and being configured in 3D space in accordance with known three-dimensional relationships with each other;

detecting, from a 2D image of the three-dimensional target acquired by at least one camera, a plurality of target element images corresponding to the plurality of target elements; and

determining the measurement relating to the object based on a spatial orientation of the three-dimensional target determined based on the target element images and the three-dimensional relationships among the target elements.