THREE-DIMENSIONAL SCANNER AND METHOD OF OPERATION

• US 20140152769A1
• Filed: 12/05/2012
• Published: 06/05/2014
• Est. Priority Date: 12/05/2012
• Status: Abandoned Application

• Current Assignee: Faro Technologies Incorporated
• Original Assignee: Faro Technologies Incorporated
• Inventors: Atwell, Paul, Briggs, Clark H., Stokes, Burnham, Wilson, Christopher Michael
• Application Number:
  US13/705,736
• Publication Number:
  US 20140152769A1
• Time in Patent Office: Days
• US Class Current: 348/46
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns
• CPC Class Codes: H04N 13/207 using a single 2D image sensor

Abstract

A three-dimensional scanner is provided. The scanner includes a projector that emits a light pattern onto a surface. The light pattern includes a first region having a pair of opposing saw-tooth shaped edges and a first phase. A second region is provided in the light pattern having a pair of opposing saw-tooth shaped edges and a second phase, the second region being offset from the first region by a first phase difference. A third region is provided in the light pattern having a third pair of opposing saw-tooth shape edges and having a third phase, the third region being offset from the second region by a second phase difference. A camera is coupled to the projector and configured to receive the light pattern. A processor determines three-dimensional coordinates of at least one point on the surface from the reflected light of the first region, second region and third region.

Claims

1. A three-dimensional scanner comprising:

a projector configured to emit a light pattern onto a surface, the light pattern comprising;

a first region having a first pair of opposing saw-tooth shaped edges, the first region having a first phase;

a second region having a second pair of opposing saw-tooth shaped edges, the second region having a second phase, the second region being offset from the first region by a first phase difference;

a third region having a third pair of opposing saw-tooth shape edges, the third region having a third phase, the third region being offset from the second region by a second phase difference;

a camera coupled to the projector and configured to receive light from the light pattern reflected from the surface; and

a processor electrically coupled to the camera to determine three-dimensional coordinates of at least one point on the surface from a reflected light of the first region, the second region and the third region.

2. The scanner of claim 1 wherein each of the first pair of opposing saw-tooth shaped edges includes a repeating pattern, the repeating pattern having a period defined by a distance between two adjacent peaks, the first phase difference and the second phase difference being the period times one divided by a predetermined number defined by a number of different phase regions in the light pattern.

3. The scanner of claim 2 wherein the first region has a first phase number defined at least by the period and the second region has a second phase number defined at least by the period.

4. The scanner of claim 3 wherein the first phase number minus the second phase number is an odd number.

5. The scanner of claim 4 wherein the first phase number minus the second phase number is an even number.

6. The scanner of claim 3 wherein the light pattern further comprises:

a first plurality of regions on one end, each of the first plurality of regions having a pair of saw-tooth shaped edges;

a second plurality of regions arranged on an opposite end, the second plurality of regions each having a pair of saw-tooth shape edges;

wherein each of adjacent regions in the first plurality of regions having a phase relationship such that a phase number of a second adjacent segment minus a phase number of a first adjacent region is an odd number; and

wherein each of adjacent regions in the second plurality of regions having a phase relationship such that a phase number of a fourth adjacent region minus a phase number of a third adjacent region is an even number.

7. A three-dimensional scanner comprising:

a housing;

a projector disposed within the housing and configured to emit a light pattern having a first plurality of regions, each of the first plurality of regions have a first pair of edges with saw-tooth shape, the first plurality of regions comprising a predetermined number of evenly spaced phases, the evenly spaced phases being offset from each other in a first direction along a length of the first plurality of regions;

a digital camera disposed within the housing and configured to receive light from the light pattern reflected off a surface; and

,

a processor coupled for communication to the digital camera, the processor being responsive to executable computer instructions when executed on the processor for determining three-dimensional coordinates of at least one point on the surface in response to receiving light from the light pattern.

8. The scanner of claim 7 wherein each of the first plurality of regions having a phase number, the first plurality of regions further comprising:

a second plurality of regions arranged on one end of the light pattern, wherein the difference of the phase number of a region and a previous region in the second plurality of regions is an odd number; and

,

a third plurality of regions arranged on an opposite end of the light pattern, wherein the difference of the phase number of a region and a previous region in the third plurality of regions is an even number.

9. The scanner of claim 8 wherein the difference in phase between adjacent regions in the first plurality of regions is determined by subtracting the phase number of a first region from the phase number of a second region.

10. The scanner of claim 9 wherein when the difference in phase between the adjacent regions is a negative number, the difference in phase between the adjacent regions in the first plurality of regions is determined by subtracting the phase number of the first region from the phase number of the second region and adding the predetermined number of evenly spaced phases.

11. The scanner of claim 7 wherein the housing is sized to be carried and operated by a single person.

12. The scanner of claim 11 further comprising a display coupled to the housing and electrically coupled to the processor.

13. The scanner of claim 12 wherein the processor is further responsive to executable computer instructions for displaying the at least one point on the display.

14. The scanner of claim 8 wherein the first plurality of regions has a trapezoidal shape.

15. The scanner of claim 14 wherein the predetermined number of evenly spaced phases is equal to eleven.

16. A method of determining three-dimensional coordinates of a point on a surface, the method comprising:

emitting a light pattern from a projector, the light pattern including a first plurality of regions each having a pair of edges with a saw-tooth shape, wherein adjacent regions in the first plurality of regions have a different phase, the projector having a source plane;

receiving light from the light pattern reflected off of the surface with a digital camera, the digital camera having an image plane, the digital camera and the projector being spaced apart by a baseline distance;

acquiring an image of the light pattern on the image plane;

determining at least one center on the image plane for at least one of the first plurality of regions;

defining an image epipolar line through the at least one center on the image plane;

determining at least one image point on the source plane corresponding to the at least one center;

defining a source epipolar line through that at least one image point on the source plane; and

determining three-dimensional coordinates for a least one point on the surface based at least in part on the at least one center, the at least one image point and the baseline distance.

17. The method of claim 16 wherein each of the regions in the first plurality of regions has a phase number.

18. The method of claim 17 further comprising:

determining the phase number for each of the regions in the first plurality of regions in the image, the first plurality of regions including a first region, a second region and a third region;

determining a first phase difference between the first region and the second region;

determining a second phase difference between the second region and the third region.

19. The method of claim 18 further comprising generating a first code from the first region and the second region, the first code including the first phase difference and the second phase difference.

20. The method of claim 19 further comprising generating a plurality of codes for each three sequential regions in the first plurality of regions, wherein each code of the plurality of codes is unique within the light pattern.

21. The method of claim 18 wherein:

the first plurality of regions includes a second plurality of regions on one end and a third plurality of regions on an opposite end;

each of the regions in the second plurality of regions having a third phase difference, the third phase difference being defined as the difference between the phase number of a region and a preceding line in the second plurality of regions, the third phase difference being an odd number; and

each of the regions in the third plurality of regions having a fourth phase difference, the fourth phase difference being defined as the difference between the phase number of a region and a preceding region in the third plurality of regions, the fourth phase difference being an even number.

22. The method of claim 21 wherein when the third phase difference for a region is a negative number, the third phase difference for that region is defined as the difference between the phase number of the region and a preceding region plus a predetermined number, the predetermined number being equal to a number of different phase regions in the light pattern.

23. The method of claim 22 wherein a period of the saw-tooth shape is a distance between two adjacent peaks, difference in phase between two adjacent regions in the first plurality of regions being based on the predetermined number and the period.