Color vision vehicle wheel alignment system

• US 20030187610A1
• Filed: 03/26/2003
• Published: 10/02/2003
• Est. Priority Date: 03/26/2002
• Status: Active Grant

• Current Assignee: Hunter Engineering Company
• Original Assignee: Hunter Engineering Company
• Inventors: Voeller, David A., Strege, Timothy A., Dorrance, Daniel R., Golab, Thomas, Burns, Leigh R. Jr.
• Granted Patent: US 7,302,093 B2
• Time in Patent Office: Days
• US Class Current: 702/151
• 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 2210/30 Reference markings, reflector, scale or other passive device
• CPC Class Codes: G06T 7/73 using feature-based methods

Abstract

An improved computer controlled optical imaging vehicle wheel alignment system configured to obtain one or more color images of optical targets associated with a vehicle, and to process the color images to obtain vehicle wheel alignment measurements.

Claims

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;

at least one camera disposed to generate at least one color image of said at least one optical target, said camera configured with an imaging element sensitive to detect a plurality of colors; and

a computer operatively connected to said at least one camera, said computer configured to receive and process said at least one color 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 imaging element is sensitive to record a plurality of colors at each pixel location in said image.

3. The vehicle wheel alignment apparatus of claim 1 wherein said computer is configured to receive pixel data representative of said at least one color image, said pixel data including two or more color channels;

said computer further configured to process pixel data associated with at least one of said two or more color channels to determine one or more optical target parameters.

4. The vehicle wheel alignment apparatus of claim 1 where said at least one camera is further configured to generate said at least one color image of said at least one optical target when said optical target is illuminated by ambient light.

5. The vehicle wheel alignment apparatus of claim 1 further comprising a first optical target and a second optical target, said first optical target including at least one optical element having a first color, and said second optical target including at least one optical element having a second color.

6. The vehicle wheel alignment apparatus of claim 5 further comprising a third optical target and a fourth optical target, said third optical target including at least one optical element having a third color, and said fourth optical target including at least one optical element having a fourth color.

7. The vehicle wheel alignment apparatus of claim 1 wherein said at least one optical target includes at least one optical element having a first color and at least one optical element having a second color.

8. The vehicle wheel alignment apparatus of claim 7 wherein said at least one optical element having said first color and said at least one optical element having said second color are disposed in a partially overlapping configuration.

9. The vehicle wheel alignment apparatus of claim 7 wherein said at least one optical target includes at least one optical element having a third color.

10. The vehicle wheel alignment apparatus of claim 9 wherein each optical element is disposed in a partially overlapping configuration with at least one of each optical element having a different color.

11. The vehicle wheel alignment apparatus of claim 1 wherein each of said at least one optical targets is identified by a color.

12. The vehicle wheel alignment apparatus of claim 11 wherein said at least one optical element having said first color is configured to provide target orientation information.

13. The vehicle wheel alignment apparatus of claim 1 wherein said at least one optical target includes at least one optical element composed of a plurality of portions, each of said portions having a discrete color.

14. The vehicle wheel alignment apparatus of claim 13 wherein each of said plurality of portions is configured to provide at least one target reference point.

15. The vehicle wheel alignment apparatus of claim 1 wherein said at least one camera requires a minimum ambient light level to receive said at least one color image of said at least one optical target;

and wherein said computer is further configured to provide an indication to an operator if an ambient light level is below said minimum ambient light level.

16. An optical target adapted to provide images functionally related to one or more vehicle wheel alignment angles, comprising:

at least one optical element having a first color hue;

at least one optical element having a second color hue; and

at least one optical element having a predetermined tone selected from a set consisting of black tones and white tones.

17. The optical target of claim 16 wherein one member of the sets of said at least one optical element having a first color hue, said at least one optical element having a second color hue, and said at least one optical element having a predetermined tone, is configured to define a target orientation.

18. The optical target of claim 16 wherein said at least one optical element having said predetermined tone defines a background against which said at least one optical element having said first color hue and said at least one optical element having said second color hue are set.

19. The optical target of claim 16 further including at least one optical element having a plurality of portions, each of said portions having a unique color hue.

20. A vehicle wheel alignment apparatus for determining the alignment of the wheels of a vehicle, said apparatus comprising:

at least one color optical target including a plurality of color optical elements, said color optical target adapted to provide images functionally related to vehicle wheel alignment parameters;

at least one color camera disposed to receive at least one color image of said at least one color optical target, said camera configured with an imaging element sensitive to distinguish a plurality of colors corresponding to said plurality of color optical elements; and

a computer operatively connected to said at least one color camera, said computer configured to processes said at least one color image to extract one or more target reference points, and to determine one or more values of wheel alignment parameters of the vehicle from said one or more target reference points.

21. The vehicle wheel alignment apparatus of claim 20 wherein said imaging element is sensitive to distinguish a plurality of colors at each pixel location in color image.

22. The vehicle wheel alignment apparatus of claim 20 wherein said imaging element is sensitive to interpolate a plurality of colors at each pixel location in color image.

23. The vehicle wheel alignment apparatus of claim 20 wherein said at least one optical element is a predetermined white color.

24. The vehicle wheel alignment apparatus of claim 20 wherein said at least one color optical target is a three-dimensional structure having a plurality of colored facets.

25. The vehicle wheel alignment apparatus of claim 20 wherein said plurality of color optical elements include at least one color optical element of a first color, and at least one color optical element of a second color.

26. The vehicle wheel alignment apparatus of claim 20 wherein at least one of said color optical elements is a circle.

27. A vehicle wheel alignment apparatus for determining the alignment of the wheels of a vehicle, said apparatus comprising:

at least one color optical target adapted for association with a vehicle wheel, said color optical target having a surface coated with a multi-layer optical interference coating configured to alter an apparent color of said at least one color optical target responsive to a viewing angle;

at least one color camera disposed to view said at least one color optical target associated with a vehicle wheel to generate at least one color image; and

a computer operatively connected to said at least one color camera, said computer configured to processes said at least one color image to identify at least an orientation of said at least one color optical target from said apparent color of said optical target color.

28. The vehicle wheel alignment apparatus of claim 27 wherein said at least one color camera includes an imaging element sensitive to record a plurality of colors at each pixel location in said image.

29. The vehicle wheel alignment apparatus of claim 27 wherein said at least one color camera includes an imaging element sensitive to interpolate a plurality of colors at each pixel location in said image.

30. A method for determining the alignment of one or more wheels of a motor vehicle, comprising the steps of:

mounting at least one optical target in an operative relationship to a wheel of said motor vehicle;

obtaining at least one color image of a field of view including said at least one optical target, said at least one color image including a plurality of colors;

identifying said at least one optical target in said image;

calculating a position and orientation of said identified optical target in said field of view; and

determining an alignment of said wheel of said motor vehicle based upon said observed position and orientation of said identified optical target.

31. The method of claim 30 for determining the alignment of one or more wheels of a motor vehicle wherein the step of calculating a position and orientation of said identified optical target in said field of view includes

identifying a first set of target reference points in said image from at least one optical element on said optical target having a first color;

identifying a second set of target reference points in said image from at least one optical element on said optical target having a second color; and

utilizing said identified first and second sets of identified target reference points to calculate a position and orientation of said identified optical target in said field of view.

32. The method of claim 30 for determining the alignment of one or more wheels of a motor vehicle wherein the step of identifying said at least one optical target in said image includes the step of identifying a portion of said image having a predetermined color, said predetermined color corresponding to a predetermined color disposed on said optical target.

33. A method for determining the alignment of one or more wheels of a motor vehicle, comprising the steps of:

mounting at least one optical target in an operative relationship to a wheel of said motor vehicle;

obtaining at least one color image of a field of view including said at least one optical target, said at least one color image composed of a plurality of color channels, each color channel including data representative of an observed color level at each pixel location for said corresponding color;

identifying said at least one optical target in said at least one color image utilizing at least one color channel;

calculating a position and orientation of said identified optical target in said field of view utilizing at least one color channel; and

determining an alignment of said wheel of said motor vehicle based upon said observed position and orientation of said identified optical target.

34. The method of claim 33 for determining the alignment of one or more wheels of a motor vehicle wherein the step of calculating a position and orientation of said identified optical target in said field of view further includes obtained at least one set of target reference points from each of said plurality of color channels.

35. An apparatus for determining the alignment of a wheel of a vehicle, said apparatus comprising:

a known optical target associated with said wheel on said vehicle, said known optical target having two or more sets of overlapping optical elements of different colors, each set of optical elements including a plurality of parallel straight stripes of the same color disposed on a background, each of said straight color stripes having defined edges so that if construction lines were drawn along the defined edges of each stripe, they would intersect in a set of target reference points;

at least one color camera for obtaining at least one color image of said optical target; and

at least one computer configured for constructing from said color image of said optical target, a plurality of lines corresponding to projections onto said color image of said defined edges of said straight stripes, and for determining from said constructed lines the alignment of said wheel.

36. An optical target adapted to provide images functionally related to one or more vehicle wheel alignment angles, comprising:

at least one optical element having a first color;

at least one optical element having a second color; and

a background on which said at least one optical element having a first color and said at least one optical element having a second color are set.

37. The optical target of claim 36 wherein said background has a third color which is distinct from said first and second colors.

38. The optical target of claim 36 wherein said background has a tone which is distinct from said first and second colors.

39. The optical target of claim 38 wherein said background has a tone which is selected from a set consisting of black tones and white tones.

40. The optical target of claim 36 wherein each of said optical elements has a shape selected from the set consisting of circles, ellipses, and polygons.