GEOMETRIC CORRECTION OF ROUGH WIREFRAME MODELS DERIVED FROM PHOTOGRAPHS

• US 20110187713A1
• Filed: 02/01/2011
• Published: 08/04/2011
• Est. Priority Date: 02/01/2010
• Status: Active Grant

• Current Assignee: EagleView Technologies Incorporated (Eagleview Technologies, Inc. /Wa/)
• Original Assignee: EagleView Technologies Incorporated (Eagleview Technologies, Inc. /Wa/)
• Inventors: Keane, John F., Pershing, Chris
• Granted Patent: US 9,911,228 B2
• Time in Patent Office: Days
• US Class Current: 345/420
• CPC Class Codes: G06T 17/20 Finite element generation, e.g. wire-frame surface description, tesselation
• CPC Class Codes: G06T 19/20 Editing of 3D images, e.g. changing shapes or colours, aligning objects or positioning parts
• CPC Class Codes: G06T 2210/04 Architectural design, interior design

Abstract

Geometric correction of rough wireframe models derived from photographs may include rectification of either a 2D or 3D original wireframe model of a roof structure, derivation of metadata from the original wireframe, in-plane normalization of the wireframe, extrusion into a “rough” 3D wireframe based on the normalized wireframe, and correction of the “rough” 3D wireframe. The correction and normalization may be an iterative process based on initial pitch values, metadata derived from the original or corrected wireframe models and defined constraints regarding relationships between roof portions or segments. The iterative process may repeat adjusting the wireframe model until the adjusting converges to a stable state according to the various defined constraints.

Claims

1. A method comprising:

assigning an initial set of pitch values to a plurality of facets of a roof;

automatically adjusting lateral positions of points associated with one or more first line segments of the roof identified as one or more ridge segments to accommodate pitch values of the initial set of pitch values associated with facets that share the one or more ridge segments or share endpoints of the one or more roof segments; and

automatically adjusting lateral positions of points associated with one or more second line segments of the roof identified as a junction or seam between adjacent facets of the roof to accommodate pitch values of the initial set of pitch values associated with the adjacent facets.

2. The method according to claim 1 further comprising repeating the automatically adjusting lateral positions of points associated with the one or more first line segments until the adjusting of lateral positions of points converges to a stable state.

3. The method according to claim 2 further comprising automatically repeating the automatically adjusting lateral positions of points associated with the one or more second line segments until the adjusting of lateral positions of points converges to a stable state.

4. The method according to claim 3 further comprising repeating the assigning an initial set of pitch values before repeating the automatically adjusting lateral positions of points associated with the one or more first line segments and before repeating the automatically adjusting lateral positions of points associated with the one or more second line segments.

5. The method according to claim 1, further comprising assigning an initial set of orientations to the plurality of roof facets.

6. The method according to claim 1, further comprising automatically generating a first 3D wireframe of the roof based on the adjusted lateral positions of points associated with the one or more first line segments and the adjusted lateral positions of points associated with the one or more second line segments.

7. The method according to claim 6 wherein the automatically generating the first 3D wireframe is further based on and initial set of input roof elevation values.

8. The method according to claim 7 further comprising automatically generating a second 3D wireframe of the roof to satisfy a set of constraints by changing geometric characteristics of the first 3D wireframe that are inconsistent with the constraints.

9. The method according to claim 8 wherein the changing geometric characteristics of the first 3D wireframe that are inconsistent with the constraints includes one or more of the following:

preserving a footprint of the first 3D wireframe;

correcting angles of intersection between line segments of the first 3D wireframe;

straightening line segments of the first 3D wireframe;

specifying a particular pitch for one or more facets of the roof;

allowing a pitch of one or more facets of the roof to conform with other constraints;

enforcing relationships between line segments and facets of the first 3D wireframe to satisfy symmetry requirements;

constraining groups of points or line segments of the first 3D wireframe to reside at a same elevation;

constraining two or more different groups of points or line segments of the first 3D wireframe to maintain a particular difference in elevation;

enforcing symmetry between nearly symmetric objects in the first 3D wireframe.

10. The method of claim 8 wherein the automatically generating a second 3D wireframe of the roof to satisfy a set of constraints by changing geometric characteristics of the first 3D wireframe that are inconsistent with the constraints includes using metadata regarding relationships between roof line segments and points.

11. The method according to claim 1, further comprising deriving metadata from an initial wireframe of the roof, the metadata including information regarding one or more of the following:

nearest neighbor points of the points associated with the one or more first line segments, nearest neighbor line segments of the one or more first line segments, nearest neighbor points of the points associated with the one or more second line segments, nearest neighbor line segments of the one or more second line segments, roof line segment membership in polygons, whether line segments of the roof are edges or ridges, which points resemble roof hip junctions of the roof, which points resemble roof gable junctions of the roof, which points resemble roof corners on a perimeter of the roof, or identification of roof geometric shape primitives;

wherein the metadata is used in one or both of;

the automatically adjusting lateral positions of points associated with one or more first line segments, and the automatically adjusting lateral positions of points associated with one or more second line segments.

12. The method according to claim 11 wherein the initial wireframe is a 2D wireframe.

13. The method according to claim 11 wherein the initial wireframe is a 3D wireframe.

14. The method according to claim 1 wherein the assigning an initial set of pitch values to a plurality of facets of a roof comprises automatically analyzing neighboring polygons of the roof to infer relative pitch values.

15. The method according to claim 1 wherein the initial set of pitch values are automatically assigned based on received input pitch values from a user.

16. A method comprising:

generating metadata from a wireframe model of a roof;

moving a location of roof junction points from the wireframe model to a normalized roof outline based on the generated metadata;

modifying a shape of the roof facets of the wireframe model; and

outputting a revised wireframe model based on the moved junction points and modified shapes to more closely approximate the actual shape of the roof.

17. The method according to claim 16 wherein the modifying the shape of the roof facets of the wireframe model includes:

comparing the roof facets of the wireframe model to a database of roof geometric shape primitives; and

modifying the shape of at least one of the roof facets of the wireframe model to match the geometric shape of a previously stored primitive.

18. The method according to claim 17 where in one of the primitives is a hip or gable.

19. The method according to claim 16 wherein the modifying the shape of the roof facets of the wireframe model is based on the generated metadata.

20. The method according to claim 16 wherein the wireframe model is a 2D top view of the roof.

21. The method according to claim 20 further including:

generating a 3D wireframe of the roof based on the revised wireframe model.

22. A non-transitory computer readable medium having computer executable instructions thereon that, when executed, cause a computer processor to perform the following:

automatically adjusting lateral positions of points associated with one or more first line segments of a roof identified as one or more ridge segments to accommodate pitch values of an initial set of pitch values associated with facets that share the one or more ridge segments or share endpoints of the one or more roof segments; and

automatically adjusting lateral positions of points associated with one or more second line segments of the roof identified as a junction or seam between adjacent facets of the roof to accommodate pitch values of the initial set of pitch values associated with the adjacent facets.

23. The method according to claim 22 wherein the computer executable instructions thereon, when executed, further cause the computer processor to perform automatically generating a first 3D wireframe of the roof based on the adjusted lateral positions of points associated with the one or more first line segments and the adjusted lateral positions of points associated with the one or more second line segments.

24. The method according to claim 23 wherein the generating the first 3D wireframe is further based on and initial set of input roof elevation values.

25. The method according to claim 23 wherein the computer executable instructions thereon, when executed, further cause the computer processor to perform automatically generating a second 3D wireframe of the roof to satisfy a set of constraints by changing geometric characteristics of the first 3D wireframe that are inconsistent with the constraints.

26. A non-transitory computer readable medium having computer executable instructions thereon that, when executed, cause a computer processor to perform the following:

generating metadata from a wireframe model of a roof, the wireframe model having roof junction points and roof facets;

moving a location of roof junction points from the wireframe model to a normalized roof outline based on the generated metadata;

modifying a shape of the roof facets of the wireframe model; and

outputting a revised wireframe model based on the moved junction points and modified shapes to more closely approximate the actual shape of the roof.

27. The non-transitory computer readable medium of claim 26 wherein the modifying the shape of the roof facets of the wireframe model includes:

comparing the roof facets of the wireframe model to a database of roof geometric shape primitives; and

modifying the shape of at least one of the roof facets of the wireframe model to match the geometric shape of a previously stored primitive.

28. The non-transitory computer readable medium of claim 26, wherein the computer executable instructions thereon, when executed, further cause the computer processor to perform generating a 3D wireframe of the roof based on the revised wireframe model.