Three-dimensional coordinate measuring device

• US 7,372,581 B2
• Filed: 04/11/2006
• Issued: 05/13/2008
• Est. Priority Date: 04/11/2005
• Status: Active Grant

• Current Assignee: Faro Technologies Incorporated
• Original Assignee: Faro Technologies Incorporated
• Inventors: Raab, Simon, Bridges, Robert E.
• Primary Examiner(s): Nguyen; Tu T
• Application Number:
  US11/402,355
• Publication Number:
  US 20060227210A1
• Time in Patent Office: 763 Days
• Field of Search: None
• US Class Current: 356/614
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• CPC Class Codes: G01B 2210/58 Wireless transmission of information between a sensor or probe and a control or evaluation unit
• CPC Class Codes: G01S 3/784 using a mosaic of detectors
• CPC Class Codes: G01S 5/163 Determination of attitude using inertial means G01C9/00; control of attitude G05D1/49

Abstract

An optical camera three-dimensional coordinate measuring system for use with objects to be measured is described. The system may include a compact, easily moveable, and rotatable, target of known dimensions comprising a spherical surface to be placed in contact with the object to be measured at different points along the object to be measured thereby eliminating the necessity of using a larger extended probe contact tip extending from the target to the object to be measured. At least one or more light emitting source may be located in a known position in the target such as the center of the spherical surface for example. At least two cameras located at different and known coordinate locations for receiving light from the light emitting source from different optical perspectives may be included. The position in three dimensional coordinates of the object to be measured is computed from the images taken by the cameras.

Claims

1. An optical camera three-dimensional coordinate measuring system for use with objects to be measured comprising:

a compact, easily moveable, and rotatable, target of known dimensions comprising a spherical surface to be placed in direct contact with the object to be measured at different points along the object to be measured thereby eliminating the necessity of using a larger extended probe contact tip extending from the target to the object to be measured;

at least one or more light emitting source located in a known position in the target and wherein the light emitting source is located at the spherical center of the target having a spherical surface;

at least two cameras located at different and known coordinate locations for receiving light from the light emitting source from different optical perspectives; and

a processor for computing the position in three dimensional coordinates of the object to be measured from images of the light emitting source on the cameras, from the known positions of the cameras, from the known dimensions of the target, and from the known position of the light emitting source in the target.

2. The system of claim 1 wherein the target comprises a light transmissive sphere illuminated by the light source and coated with a partially reflective coating and located inside a second light transmissive sphere.

3. The system of claim 1 wherein the target has a handle attached to the target.

4. The system of claim 1 wherein the spherical surface is placed in contact with the object to be measured;

and further comprising a light source placed in relation to a mirror such that the center of the spherical surface is located at the virtual image position of the light source in the target.

5. The system of claim 1 wherein the target is a partial sphere open on at least one side.

6. The system of claim 1 wherein the at least two cameras each include at least one or more photosensitive arrays which are used to determine three dimensional coordinates of the object to be measured from images of the light emitting source recorded on the photosensitive arrays that the light from the light emitting source is incident upon.

7. A Coordinate Measurement Machine (CMM) for use with objects to be measured comprising:

a spherical or cylindrical shaped geometric target of known dimensions to be placed in contact with the object to be measured at different points along the object to be measured;

at least one or more light emitting diode (LED) light source located at a point of symmetry on the spherical or cylindrical shaped geometric target;

at least two photosensitive cameras located at different and known coordinate locations for receiving light from the light emitting diode (LED) light source from different optical perspectives;

a processor for computing the position in three dimensional coordinates of the object to be measured from images of the light emitting diode (LED) light source recorded on the cameras, from the known positions of the cameras, from the known dimensions of the spherical or cylindrical shaped geometric target, and from the known position of the light emitting source located in the spherical or cylindrical geometric target;

wherein the at least two cameras each include at least one or more photosensitive arrays which are used to determine coordinates of the object to be measured from the recorded images of the light emitting diode (LED) light source on the photosensitive arrays that the light from light emitting diode (LED) light source is incident upon.

8. The machine of claim 7 wherein the light emitting diode (LED) light source is located along the axis of a target having cylindrical symmetry and wherein a portion of the target is structured to fit into a hole of specified diameter in the object to be measured.

9. The machine of claim 7 wherein the light emitting diode (LED) light source is located at the spherical center of the target having a spherical surface.

10. The machine of claim 7 wherein the target comprises a partially light transmissive sphere illuminated by light emitting diode (LED) light source and coated with a partially reflective coating and located inside a second light transmissive sphere.

11. The machine of claim 7 wherein the target has a handle attached to the target.

12. The machine of claim 7 wherein a spherical surface is placed in contact with the object to be measured;

and further comprising a light source placed in relation to a mirror such that the center of the spherical surface is located at the virtual image position of the light source in the target.

13. The machine of claim 7 wherein the target is a partial sphere open on at least one side.

14. An optical camera three-dimensional coordinate measuring method for measuring objects comprising:

placing a compact, easily moveable, and rotatable, target of known dimensions comprising a spherical surface in direct contact with the object to be measured at different points along the object to be measured thereby eliminating the necessity of using a larger extended probe contact tip extending from the target to the object to be measured;

emitting light from the target from at least one or more light emitting source located in a known position in the target;

recording images of the light source at least two cameras located at different and known coordinate locations for receiving light from the light emitting source from different optical perspectives; and

computing the position in three dimensional coordinates of the object to be measured from images of the light emitting source on the cameras, from the known positions of the cameras, from the known dimensions of the target, and from the known position of the light emitting source in the target.

15. The method of claim 14 wherein the light emitting source is located at the spherical center of the target having a spherical surface.

16. The method of claim 15 wherein the target comprises a light transmissive sphere illuminated by the light source and coated with a partially reflective coating and located inside a second light transmissive sphere.

17. The method of claim 15 wherein the spherical surface is placed in contact with the object to be measured;

and further comprising a light source placed in relation to a mirror such that the center of the spherical surface is located at the virtual image position of the light source in the target.

18. The method of claim 15 wherein the target is a partial sphere open on at least one side.

19. An optical camera three-dimensional coordinate measuring system for use with objects to be measured comprising:

a compact, easily moveable, and rotatable target of known dimensions comprising a cylindrical surface to be placed in at least one or more holes in the object to be measured thereby eliminating the necessity of using a larger extended probe contact tip extending from the target to the object to be measured;

at least one or more light emitting sources wherein the light emitting source is located at a known position on the target along an axis of cylindrical symmetry;

at least two cameras located at different and known coordinate locations for receiving light from the light emitting source from different optical perspectives; and

a processor for computing the position in three dimensional coordinates of the object to be measured from images of the light emitting source on the cameras, from the known positions of the cameras, from the known dimensions of the target, and from the known position of the light emitting source in the target.