Accurate smooth occluding contours

Patent metadata

Field	Value
Publication number	US-11941746-B2
Application number	US-202117466670-A
Country	US
Kind code	B2
Filing date	Sep 3, 2021
Priority date	Sep 3, 2021
Publication date	Mar 26, 2024
Grant date	Mar 26, 2024

Abstract

Embodiments are disclosed for computing accurate smooth occluding contours. In one embodiment, a method of computing accurate smooth occluding contours includes projecting a boundary polygon associated with a first region of a three-dimensional (3D) object to a two-dimensional (2D) image plane, the boundary polygon comprising a plurality of contour vertices and edges connecting the plurality of contour vertices, triangulating the first region in the 2D image plane to generate a 2D triangulation, and generating a 3D mesh for the first region by mapping the 2D triangulation to the 3D object.

First claim

We claim:

1. A computer-implemented method comprising:
projecting a boundary polygon associated with a first region of a three-dimensional (3D) object to a two-dimensional (2D) image plane, the boundary polygon comprising a plurality of contour vertices and edges connecting the plurality of contour vertices;
triangulating the first region in the 2D image plane to generate a 2D triangulation; and
generating a 3D mesh for the first region by mapping the 2D triangulation to the 3D object by connecting at least one pair of contour vertices with a path on a surface of the 3D object which corresponds to a straight line connection in the 2D image plane, and refining the 2D triangulation based on sample points collected along the path on the surface of the 3D object.

2. The computer-implemented method of claim 1 , further comprising:
iteratively generating a 3D mesh for each remaining region of the 3D object by:
projecting a boundary polygon associated with that region to the 2D image plane;
triangulating that region in the 2D image plane to generate a 2D triangulation; and
mapping the 2D triangulation for that region to the 3D object.

3. The computer-implemented method of claim 2 , further comprising:
generating an output mesh by combining each 3D mesh corresponding to each region.

4. The computer-implemented method of claim 3 , further comprising:
providing the output mesh to a mesh contour detection and stylization system, wherein the mesh contour detection and stylization system generates a stylized line drawing based on the output mesh and a user-indicated style; and
causing the stylized line drawing to be returned to a user.

5. The computer-implemented method of claim 3 , further comprising:
providing the output mesh to a mesh contour detection and stylization system, wherein the mesh contour detection and stylization system generates a vector graphics object corresponding to an occluding contour of the output mesh; and
causing the vector graphics object to be returned to a user.

6. The computer-implemented method of claim 1 , wherein generating a 3D mesh for the first region by mapping the 2D triangulation to the 3D object, further comprises:
selecting a first contour vertex and a second contour vertex;
identifying the path connecting on the 3D object connecting the first contour vertex to the second contour vertex;
generating sample points along the path on the 3D object; and
generating a refined 2D triangulation using the contour vertices and the sample points.

7. The computer-implemented method of claim 6 , wherein generating sample points along the path on the 3D object, further comprises:
adding the sample points that were generated on the path in a direction of travel from the first contour vertex to the second contour vertex; and
discarding the sample points that were generated on the path in a direction of travel from the second contour vertex to the first contour vertex.

8. The computer-implemented method of claim 1 , wherein the 3D object is a self-overlapping object, a weakly self-overlapping object, or a weakly self-overlapping object with one or more holes.

9. The computer-implemented method of claim 1 , further comprising:
receiving a request to generate occluding contours for the 3D object, the request including the 3D object and a viewpoint;
inserting contour vertices into an initial mesh of the 3D object, the contour vertices corresponding to at least one occluding contour on the 3D object; and
partitioning the 3D object into a plurality of regions based at least on the contour vertices.

10. A non-transitory computer-readable storage medium including instructions stored thereon which, when executed by at least one processor, cause the at least one processor to:
project a boundary polygon associated with a first region of a three-dimensional (3D) object to a two-dimensional (2D) image plane, the boundary polygon comprising a plurality of contour vertices and edges connecting the plurality of contour vertices;
triangulate the first region in the 2D image plane to generate a 2D triangulation; and
generate a 3D mesh for the first region by mapping the 2D triangulation to the 3D object by connecting at least one pair of contour vertices with a path on a surface of the 3D object which corresponds to a straight line connection in the 2D image plane, and refining the 2D triangulation based on sample points collected along the path on the surface of the 3D object.

11. The non-transitory computer-readable storage medium of claim 10 , wherein the instructions, when executed, further cause the at least one processor to:
iteratively generate a 3D mesh for each remaining region of the 3D object by:
projecting a boundary polygon associated with that region to the 2D image plane;
triangulating that region in the 2D image plane to generate a 2D triangulation; and
mapping the 2D triangulation for that region to the 3D object.

12. The non-transitory computer-readable storage medium of claim 11 , wherein the instructions, when executed, further cause the at least one processor to:
generate an output mesh by combining each 3D mesh corresponding to each region.

13. The non-transitory computer-readable storage medium of claim 12 , wherein the instructions, when executed, further cause the at least one processor to:
provide the output mesh to a mesh contour detection and stylization system, wherein the mesh contour detection and stylization system generates a stylized line drawing based on the output mesh and a user-indicated style; and
cause the stylized line drawing to be returned to a user.

14. The non-transitory computer-readable storage medium of claim 12 , wherein the instructions, when executed, further cause the at least one processor to:
provide the output mesh to a mesh contour detection and stylization system, wherein the mesh contour detection and stylization system generates a vector graphics object corresponding to an occluding contour of the output mesh; and
cause the vector graphics object.

15. The non-transitory computer-readable storage medium of claim 10 , wherein to generate a 3D mesh for the first region by mapping the 2D triangulation to the 3D object, the instructions, when executed, further cause the at least one processor to:
select a first contour vertex and a second contour vertex;
identify a path connecting on the 3D object connecting the first contour vertex to the second contour vertex;
generate sample points along the path on the 3D object; and
generate a refined 2D triangulation using the contour vertices and the sample points.

16. The non-transitory computer-readable storage medium of claim 15 , wherein to generate sample points along the path on the 3D object, the instructions, when executed, further cause the at least one processor to:
add the sample points that were generated on the path in a direction of travel from the first contour vertex to the second contour vertex; and
discard the sample points that were generated on the path in a direction of travel from the second contour vertex to the first contour vertex.

17. The non-transitory computer-readable storage medium of claim 10 , wherein the 3D object is a self-overlapping object, a weakly self-overlapping object, or a weakly self-overlapping object with one or more holes.

18. The non-transitory computer-readable storage medium of claim 10 , wherein the instructions, when executed, further cause the at least one processor to:
receive a request to generate occluding contours for the 3D object, the request inclu

Assignees

• Adobe Inc

Inventors

• Hertzmann Aaron
• Hoshyari Shayan
• Liu Chenxi

Classifications

• G06T15/20 Primary

  Perspective computation · CPC title

• G06T7/564 Primary

  from contours · CPC title

• G06T17/205

  Re-meshing · CPC title

• G06T2200/08

  involving all processing steps from image acquisition to 3D model generation · CPC title

• G06T17/20

  Finite element generation, e.g. wire-frame surface description, {tesselation} · CPC title