System and method for identifying a feature of a workpiece

• US 20070271064A1
• Filed: 05/22/2007
• Published: 11/22/2007
• Est. Priority Date: 05/16/2006
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Walton, Steven R.
• Granted Patent: US 8,050,486 B2
• Time in Patent Office: Days
• US Class Current: 702/158
• CPC Class Codes: B29C 70/32 on a rotating mould, former or core
• CPC Class Codes: B29C 70/388 Tape placement heads, e.g. component parts, details or accessories
• CPC Class Codes: B29L 2031/3082 Fuselages
• CPC Class Codes: G01B 11/245 using a plurality of fixed, simultaneously operating transducers G01B11/2408 - G01B11/2425, G01B11/255 take precedence
• CPC Class Codes: G01B 11/25 by projecting a pattern, e.g. one or more lines, moiré fringes on the object G01B11/255 takes precedence ; image analysis for depth or shape recovery G06T7/50
• CPC Class Codes: G01N 2021/8472 Investigation of composite materials
• CPC Class Codes: G01N 21/88 Investigating the presence of flaws or contamination
• CPC Class Codes: G01N 21/892 characterised by the flaw, defect or object feature examined

Abstract

A feature of a workpiece can be identified. Two-dimensional data of at least a region of a workpiece and three-dimensional data of a portion of the region of the workpiece are acquired, such as by illuminating at least the region with at least a first light source disposed at a first angle of incidence relative to a plane of the region and illuminating the portion with a second light source, such as at least one laser, disposed at a second angle of incidence greater than the first angle of incidence. An estimated location of an attribute of a feature of the workpiece is determined from the three-dimensional data, and the feature is identified by analyzing the two-dimensional data in an area surrounding the estimated location of the attribute. Attributes of features can include without limitation a point along a line of an edge.

Claims

1. A method for identifying a feature of a workpiece, the method comprising:

acquiring two-dimensional data of at least a region of a workpiece;

acquiring three-dimensional data of a portion of the region of the workpiece;

determining an estimated location of an attribute of a feature of the workpiece from the three-dimensional data; and

identifying the feature by analyzing the two-dimensional data in an area surrounding the estimated location of the attribute.

2. The method of claim 1, wherein:

the feature includes an edge; and

the attribute includes a point along a line.

3. The method of claim 1, wherein:

the feature includes a hole; and

the attribute includes a plurality of points along a circle.

4. The method of claim 1, wherein:

the feature includes a chamfered hole; and

the attribute includes a plurality of points along two concentric circles.

5. The method of claim 1, wherein identifying the feature includes performing a plurality of iterations of analyzing the two-dimensional data.

6. The method of claim 5, wherein a first iteration analyzes the two-dimensional data in a first area bounded along a first dimension with a first lineal measurement and a second dimension with a second lineal measurement.

7. The method of claim 6, wherein a second iteration analyzes the two-dimensional data in a second area bounded along the first dimension with a third lineal measurement that is longer than the first lineal measurement and the second dimension having a fourth lineal measurement that is shorter than the second lineal measurement.

8. The method of claim 1, wherein acquiring the two-dimensional data includes:

illuminating at least the region of a workpiece with at least a first light source that is disposed at a first angle of incidence relative to a plane of the region; and

sensing an image of the region.

9. The method of claim 8, wherein acquiring the three-dimensional data includes:

illuminating the portion of the region of the workpiece with a second light source that is disposed at a second angle of incidence relative to a plane of the region, the second angle of incidence being greater than the first angle of incidence; and

sensing an image of the portion of the region.

10. The method of claim 9, wherein illuminating the portion of the region of the workpiece includes directing at least one laser beam onto the portion of the region of the workpiece.

11. The method of claim 10, wherein determining an estimated attribute includes analyzing a plurality of steps along at least one line illuminated by the at least one laser beam.

13. The system of claim 11, wherein:

the first light source is disposed at a first angle of incidence relative to a plane of the region; and

the second light source is disposed at a second angle of incidence relative to a plane of the region, the second angle of incidence being greater than the first angle of incidence.

14. The system of claim 11, wherein the first light source includes first and second lighting assemblies disposed towards first and second ends of the region, respectively.

15. The system of claim 11, wherein the second light source includes at least one laser.

16. The system of claim 11, wherein the sensor includes a camera.

12. A system for identifying a feature of a workpiece, the method comprising:

a first light source configured to illuminate at least a region of a workpiece;

a second light source configured to illuminate a portion of the region of the workpiece;

a sensor configured to sense an image of the region and the portion of the region; and

a processor operatively coupled to the sensor, the processor including;

a first component configured to determine an estimated location of an attribute of a feature of the workpiece from three-dimensional data regarding the portion of the region of the workpiece; and

a second component configured to identify the feature by analyzing two-dimensional data regarding the region in an area surrounding the estimated location of the attribute.

17. A method of detecting an edge, the method comprising:

illuminating at least a region of a workpiece with a pair of first light sources that are disposed at a first angle of incidence relative to a plane of the region;

illuminating a portion of the region of the workpiece with a second light source that is disposed at a second angle of incidence relative to a plane of the region, the second angle of incidence being greater than the first angle of incidence;

capturing a frame of information;

determining an estimated location of a point along a line defining an edge within the workpiece from three-dimensional data from the frame of information; and

refining location of the edge by analyzing two-dimensional data from the frame of information in an area surrounding the estimated location of the point.

18. The method of claim 17, further comprising inputting into two-dimensional analysis a plurality of estimated locations of points along a plurality of lines that define a plurality of edges.

19. The method of claim 18, wherein analyzing the two-dimensional data includes formulating a plurality of candidate lines from the plurality of points at the plurality of estimated locations.

20. The method of claim 19, wherein analyzing the two-dimensional data further includes determining a median angle of the plurality of candidate lines.

21. The method of claim 20, wherein analyzing the two-dimensional data further includes comparing an angle of each candidate line with the median angle of the plurality of candidate lines.

22. The method of claim 21, wherein analyzing the two-dimensional data further includes invalidating a candidate line when its angle exceeds the median angle.

23. A computer software program product for detecting an edge, the computer software program product comprising:

first computer program code means for analyzing three-dimensional information to determine a plurality of estimated locations of points along a plurality of lines defining a plurality of edges; and

second computer program code means for analyzing two-dimensional information in a plurality of areas surrounding the estimated locations of the points to refine locations of the edges.

24. The computer software program product of claim 23, further comprising third computer program code means for formulating a plurality of candidate lines from the plurality of points at the plurality of estimated locations.

25. The computer software program product of claim 24, further comprising fourth computer program code means for determining a median angle of the plurality of candidate lines.

26. The computer software program product of claim 25, further comprising fifth computer program code means for comparing an angle of each candidate line with the median angle of the plurality of candidate lines.

27. The computer software program product of claim 26, further comprising sixth computer program code means for invalidating a candidate line when its angle exceeds the median angle.

28. A method of refining a location of a line, the method comprising:

inputting an estimated location of a point;

generating a first search window centered around the estimated location of the point;

subdividing first and second edges of the first search window each into a plurality of edge points;

connecting all of the edge points along the first edge with all of the edge points along the second edge to generate a first plurality of candidate lines; and

determining which of the first plurality of candidate lines has a maximized power level.

29. The method of claim 28, wherein determining which of the first plurality of candidate lines has a maximized power level includes filtering the first plurality of candidate lines.

30. The method of claim 28, further comprising extending length of the candidate line with maximized power level.

31. The method of claim 30, further comprising generating a second search window centered around the candidate line with maximized power level.

32. The method of claim 31, further comprising subdividing first and second edges of the second search window each into a plurality of edge points.

33. The method of claim 32, further comprising connecting all of the edge points along the first edge of the second search window with all of the edge points along the second edge of the second search window to generate a second plurality of candidate lines.

34. The method of claim 33, further comprising determining which of the second plurality of candidate lines has a maximized power level.

35. The method of claim 30, further comprising determining whether a predetermined edge location has been encountered.

36. A computer software program product for refining a location of a line, the computer software program product comprising:

first computer program code means for generating a first search window centered around an estimated location of a point;

second computer program code means for subdividing first and second edges of the first search window each into a plurality of edge points;

third computer program code means for connecting all of the edge points along the first edge with all of the edge points along the second edge to generate a first plurality of candidate lines; and

fourth computer program code means for determining which of the first plurality of candidate lines has a maximized power level.

37. The computer software program product of claim 36, wherein the fourth computer program code means implements a filter.

38. The computer software program product of claim 36, further comprising fifth computer program code means for extending length of the candidate line with maximized power level.

39. The computer software program product of claim 38, wherein the first computer program code means is further configured to generate a second search window centered around the candidate line with maximized power level.

40. The computer software program product of claim 39, wherein the second computer program code means is further configured to subdivide first and second edges of the second search window each into a plurality of edge points.

41. The computer software program product of claim 40, wherein the third computer program code means is further configured to connect all of the edge points along the first edge of the second search window with all of the edge points along the second edge of the second search window to generate a second plurality of candidate lines.

42. The computer software program product of claim 41, wherein the fourth computer program code means is further configured to determine which of the second plurality of candidate lines has a maximized power level.

43. The computer software program product of claim 38, further comprising sixth computer program code means for determining whether a predetermined edge location has been encountered.

44. A head assembly for performing a manufacturing operation on a workpiece, the head assembly comprising:

a tool moveable relative to a workpiece and configured to perform a manufacturing operation on a workpiece; and

a monitoring unit operatively coupled to and moveable with the tool relative to the workpiece, the monitoring unit including;

first and second lighting assemblies disposed towards first and second sides of the monitoring unit, respectively, the first and second lighting assemblies being configured to illuminate at least a region of the workpiece;

a laser assembly configured to illuminate a portion of the region of the workpiece upon which the tool has performed the manufacturing operation;

a sensor configured to sense an image of the region and the portion of the region; and

a processor operatively coupled to the sensor, the processor including;

a first component configured to determine an estimated location of an attribute of a feature of the workpiece from three-dimensional data regarding the portion of the region of the workpiece; and

a second component configured to identify the feature by analyzing two-dimensional data regarding the region in an area surrounding the estimated location of the attribute.

45. The head assembly of claim 44, wherein the tool is configured to perform an application of a composite tape onto the workpiece, and wherein the monitoring unit is configured to illuminate at least a region of the composite tape.

46. The head assembly of claim 45, wherein the tool includes:

a spindle configured to support a supply of the composite tape; and

a feed assembly configured to feed the composite tape from the supply to the workpiece, the feed assembly having a rotatable compaction roller configured to apply the composite tape onto the workpiece.

47. The head assembly of claim 44, wherein:

the first and second lighting assemblies are disposed at a first angle of incidence relative to a plane of the region; and

the laser assembly is disposed at a second angle of incidence relative to a plane of the region, the second angle of incidence being greater than the first angle of incidence.

48. The head assembly of claim 44, wherein the sensor includes a camera.

49. A system for performing a manufacturing operation on a workpiece, the system comprising:

at least one head assembly configured to perform a manufacturing operation on a workpiece, the head assembly including;

a tool moveable relative to a workpiece and configured to perform a manufacturing operation on a workpiece; and

a monitoring unit operatively coupled to and moveable with the tool relative to the workpiece, the monitoring unit including;

first and second lighting assemblies disposed towards first and second sides of the monitoring unit, respectively, the first and second lighting assemblies being configured to illuminate at least a region of the workpiece;

a laser assembly configured to illuminate a portion of the region of the workpiece upon which the tool has performed the manufacturing operation;

a sensor configured to sense an image of the region and the portion of the region; and

a processor operatively coupled to the sensor, the processor including;

a first component configured to determine an estimated location of an attribute of a feature of the workpiece from three-dimensional data regarding the portion of the region of the workpiece; and

a second component configured to identify the feature by analyzing two-dimensional data regarding the region in an area surrounding the estimated location of the attribute; and

a translation platform coupled to the at least one head assembly, the translation platform being configured to operatively position the head assembly proximate the workpiece and to systematically move the head assembly along a translation path proximate the workpiece.

50. The system of claim 49, wherein the tool is configured to perform an application of a composite tape onto the workpiece, and wherein the monitoring unit is configured to illuminate at least a region of the composite tape.

51. The system of claim 50, wherein the tool includes:

a spindle configured to support a supply of the composite tape; and

a feed assembly configured to feed the composite tape from the supply to the workpiece, the feed assembly having a rotatable compaction roller configured to apply the composite tape onto the workpiece.

52. The system of claim 49, wherein:

the first and second lighting assemblies are disposed at a first angle of incidence relative to a plane of the region; and

the laser assembly is disposed at a second angle of incidence relative to a plane of the region, the second angle of incidence being greater than the first angle of incidence.

53. The system of claim 49, wherein the sensor includes a camera.

54. A method of performing a manufacturing operation on a workpiece, the method comprising:

performing a manufacturing operation on a portion of the workpiece using a tool moveable relative to the workpiece;

simultaneously with performing the manufacturing operation, translating the tool relative to the workpiece; and

simultaneously with performing the manufacturing operation, monitoring a portion of the workpiece upon which the tool has performed the manufacturing operation, wherein the monitoring includes;

acquiring two-dimensional data of at least a region of the workpiece;

acquiring three-dimensional data of a portion of the region of the workpiece;

determining an estimated location of an attribute of a feature of the workpiece from the three-dimensional data; and

identifying the feature by analyzing the two-dimensional data in an area surrounding the estimated location of the attribute.

55. The method of claim 54, wherein performing the manufacturing operation includes applying a composite tape onto the workpiece.

56. The method of claim 55, wherein performing the manufacturing operation further includes feeding the composite tape from a tape supply to a compaction roller, and wherein applying the composite tape includes compacting the composite tape onto the workpiece using the compaction roller.

57. The method of claim 54, wherein acquiring the two-dimensional data includes:

illuminating at least the region of a workpiece with first and second lighting assemblies that are disposed at a first angle of incidence relative to a plane of the region; and

sensing an image of the region.

58. The method of claim 57, wherein acquiring the three-dimensional data includes:

illuminating the portion of the region of the workpiece with a laser assembly that is disposed at a second angle of incidence relative to a plane of the region, the second angle of incidence being greater than the first angle of incidence; and

sensing an image of the portion of the region.

59. A method of determining a power level of a line, the method comprising:

providing a filter matrix of rows and columns of first and second multipliers, the matrix having a matrix axis that is aligned with a line axis of a line to be measured, the first multipliers being arranged in rows on a first side of the matrix axis and having a first coefficient and the second multipliers being arranged in rows on a second side of the matrix axis and having a second coefficient;

summing into a first sum pixel intensities at first multipliers through which the line passes;

summing into a second sum pixel intensities at second multipliers through which the line passes; and

summing the first and second sums into a third sum that is indicative of a power level of the line.

60. The method of claim 59, wherein:

the first coefficient includes positive one; and

the second coefficient includes negative one.

61. The method of claim 59, further comprising deleting at least one row of first and second multipliers.

62. The method of claim 59, further comprising deleting at least one first multiplier and at least second multiplier from at least one row.

63. A computer software program product for determining a power level of a line, the method comprising:

first computer program code means for implementing a filter matrix of rows and columns of first and second multipliers, the matrix having a matrix axis that is aligned with a line axis of a line to be measured, the first multipliers being arranged in rows on a first side of the matrix axis and having a first coefficient and the second multipliers being arranged in rows on a second side of the matrix axis and having a second coefficient;

second computer program code means for summing into a first sum pixel intensities at first multipliers through which the line passes;

third computer program code means for summing into a second sum pixel intensities at second multipliers through which the line passes; and

fourth computer program code means for summing the first and second sums into a third sum that is indicative of a power level of the line.

64. The computer software program product of claim 63, wherein:

the first coefficient includes positive one; and

the second coefficient includes negative one.

65. The computer software program product of claim 63, further comprising fifth computer program code means for deleting at least one row of first and second multipliers.

66. The computer software program product of claim 63, further comprising sixth computer program code means for deleting at least one first multiplier and at least second multiplier from at least one row.