Method for comparing sectioned geometric data representations for selected objects

• US 20090324093A1
• Filed: 06/25/2008
• Published: 12/31/2009
• Est. Priority Date: 06/25/2008
• Status: Active Grant

• Current Assignee: Raytheon Technologies Corporation d/b/a RTX
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Lancaster, Jeffrey D., Miarecki, Michael S.
• Granted Patent: US 8,184,909 B2
• Time in Patent Office: Days
• US Class Current: 382/203
• CPC Class Codes: G06V 10/32 Normalisation of the pattern dimensions
• CPC Class Codes: G06V 10/754 involving a deformation of the sample pattern or of the reference pattern; Elastic matching

Abstract

A method for comparing a plurality of geometrical data representations each representing a spatial boundary surface of a corresponding geometrical object which surface changes over a selected extent of the object bounded thereby through providing the plurality of geometrical data representations on a common format basis, including scaling so as to each to have a common selected extent, to thereby result in a plurality of standardized spatial boundary surface geometrical data representations and comparing them at a plurality of matching section locations along each of the common extents at each of which there is a section outline curve representations. Comparing selected features of the commonly scaled section outline curve representations for such representations at corresponding ones of the selected matched section locations provides a basis for determining similarity therebetween.

Claims

1. A method for comparing a plurality of geometrical data representations each representing a spatial boundary surface of a corresponding geometrical object which surface changes over a selected extent of the object bounded thereby, the method comprising:

providing the plurality of geometrical data representations on a common format basis, including scaling so as to each to have a common selected extent, to thereby result in a plurality of standardized spatial boundary surface geometrical data representations;

selecting a plurality of section locations along each of the common extents of the standardized spatial boundary surface geometrical data representations so as to have the positions of the section locations along each common extent of a corresponding standardized spatial boundary surface geometrical data representation matched to those section locations along each of the remaining common extents of the other standardized spatial boundary surface geometrical data representations,

providing a plurality of section outline curve representations for each of the plurality of standardized spatial boundary surface geometrical data representations about selected ones of the matched section locations;

determining a pair of endpoints for each of the plurality of section outline curve representations at the selected ones of the matched section locations for each of the plurality of standardized spatial boundary surface geometrical data representations, and the chord length between each of the pairs of endpoints;

scaling the section outline curve representations to each have a common chord length at a corresponding one of the selected matched section locations for each of the plurality of standardized spatial boundary surface geometrical data representations to form commonly scaled section outline curve representations for the corresponding one of the selected matched section locations from each of the plurality of standardized spatial boundary surface geometrical data representations; and

comparing selected features of the commonly scaled section outline curve representations for the corresponding one of the selected matched section locations to provide a representation of an indication of similarity.

2. The method of claim 1 further comprising scaling the section outline curve representations to each have a common chord length at another corresponding one of the selected matched section locations for each of the plurality of standardized spatial boundary surface geometrical data representations to form commonly scaled section outline curve representations for the other corresponding one of the selected matched section locations from each of the plurality of standardized spatial boundary surface geometrical data representations.

3. The method of claim 1 wherein the comparing selected features of the commonly scaled section outline curve representations for the corresponding one of the selected matched section locations comprises calculating selected parameters based at least in part on using numerical integration over areas bounded by the commonly scaled section outline curve representations.

4. The method of claim 1 further comprising forming tolerance offset boundary curves a selected distance on either side of a selected one of the commonly scaled section outline curve representations to provide a tolerance band therebetween, and reorienting that remaining one of the commonly scaled section outline curve representations to fit within the tolerance band with as little thereof as possible outside the tolerance band.

5. The method of claim 1 further comprising orienting the commonly scaled section outline curve representations for the corresponding one of the selected matched section locations to each have its common chord length extending along a common direction.

6. The method of claim 5 further comprising forming tolerance offset boundary curves a selected distance on either side of a selected one of the commonly scaled section outline curve representations to provide a tolerance band therebetween, and reorienting that remaining one of the commonly scaled section outline curve representations to fit within the tolerance band with as little thereof as possible outside the tolerance band.

7. The method of claim 1 wherein a plurality of the geometrical data representations each include a plurality of cross section curves represented as points outlines and the providing of the plurality of geometrical data representations on a common format basis comprises providing an interpolated curve for each of a plurality of the points outline using concave and convex cubic splines and selecting a standardized points outline therefrom with points positioned in a predetermined standardized pattern.

8. The method of claim 7 wherein the providing of the plurality of geometrical data representations on a common format basis further comprises providing a faired surface through the plurality of standardized points outlines interpolated therebetween using cubic splines to form a corresponding standardized spatial boundary surface geometrical data representation.

9. The method of claim 1 wherein at least one of the geometrical data representations include cross section curves represented as points outlines and the providing of the plurality of geometrical data representations on a common format basis includes repositioning points in a points outline.

10. The method of claim 9 wherein a plurality of the geometrical data representations each include a plurality of cross section curves represented as points outlines and the providing of the plurality of geometrical data representations on a common format basis comprises providing an interpolated curve for each of a plurality of the points outline using concave and convex cubic splines and selecting a standardized points outline therefrom with points positioned in a predetermined standardized pattern.

11. The method of claim 10 wherein the providing of the plurality of geometrical data representations on a common format basis further comprises providing a faired surface through the plurality of standardized points outlines interpolated therebetween using cubic splines to form a corresponding standardized spatial boundary surface geometrical data representation.

12. The method of claim 1 wherein at least one of the geometrical data representations include cross section curves represented as points outlines and the providing of the plurality of geometrical data representations on a common format basis includes adding points in a points outline.

13. The method of claim 12 wherein a plurality of the geometrical data representations each include a plurality of cross section curves represented as points outlines and the providing of the plurality of geometrical data representations on a common format basis comprises providing an interpolated curve for each of a plurality of the points outline using concave and convex cubic splines and selecting a standardized points outline therefrom with points positioned in a predetermined standardized pattern.

14. The method of claim 12 wherein at least one of the geometrical data representations include cross section curves represented as points outlines and the providing of the plurality of geometrical data representations on a common format basis includes repositioning points in a points outline.

15. The method of claim 13 wherein the providing of the plurality of geometrical data representations on a common format basis further comprises providing a faired surface through the plurality of standardized points outlines interpolated therebetween using cubic splines to form a corresponding standardized spatial boundary surface geometrical data representation.

16. The method of claim 14 wherein a plurality of the geometrical data representations each include a plurality of cross section curves represented as points outlines and the providing of the plurality of geometrical data representations on a common format basis comprises providing an interpolated curve for each of a plurality of the points outline using concave and convex cubic splines and selecting a standardized points outline therefrom with points positioned in a predetermined standardized pattern.

17. The method of claim 16 wherein the providing of the plurality of geometrical data representations on a common format basis further comprises providing a faired surface through the plurality of standardized points outlines interpolated therebetween using cubic splines to form a corresponding standardized spatial boundary surface geometrical data representation.

18. The method of claim 17 further comprising scaling the section outline curve representations to each have a common chord length at another corresponding one of the selected matched section locations for each of the plurality of standardized spatial boundary surface geometrical data representations to form commonly scaled section outline curve representations for the other corresponding one of the selected matched section locations from each of the plurality of standardized spatial boundary surface geometrical data representations.

19. The method of claim 17 wherein the comparing selected features of the commonly scaled section outline curve representations for the corresponding one of the selected matched section locations comprises calculating selected parameters based at least in part on using numerical integration over areas bounded by the commonly scaled section outline curve representations.

20. The method of claim 1 further comprising forming tolerance offset boundary curves a selected distance on either side of a selected one of the commonly scaled section outline curve representations to provide a tolerance band therebetween, and reorienting that remaining one of the commonly scaled section outline curve representations to fit within the tolerance band with as little thereof as possible outside the tolerance band.