1 / 30

Texture Synthesis on Surfaces

This presentation by Jon Super, based on Greg Turk's research, delves into advanced texture synthesis on surfaces. It covers the goals of effective texture placement, methods to avoid seams, minimize distortion, and the use of lapped textures to enhance quality. Additionally, it discusses the creation of a mesh hierarchy, vector fields for texture flow, and the importance of sweep distance in achieving natural looks. The presentation showcases various operational techniques in multi-level synthesis, ensuring more accurate color assignments and connectivity across vertices for realistic surface texturing.

rashad
Download Presentation

Texture Synthesis on Surfaces

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Texture Synthesis on Surfaces Paper by Greg Turk Presentation by Jon Super

  2. Texture Synthesis on Surfaces +

  3. Goals of texture placement Take a 2D texture and wrap it onto a surface • Avoid noticeable seams between patches • Minimize stretching and distortion • Produce a natural-looking result

  4. The next best thing Lapped Textures – Praun et al. – SIGGRAPH00 • Uses many overlapped texture patches • Aligns patches with underlying vector field • Generally minimizes distortion

  5. The next best thing Lapped texture’s shortcomings • Low-frequency components • Boundary mismatch • Direction field singularities

  6. Texture synthesis to the rescue!

  7. Process • Create a mesh hierarchy over the model • Set up a vector field over the mesh • Calculate sweep distance for each vertex • Assign colors based on neighbors

  8. Process • Create a mesh hierarchy over the model • Set up a vector field over the mesh • Calculate sweep distance for each vertex • Assign colors based on neighbors

  9. Mesh Hierarchy Equivalent of a Gaussian pyramid to a surface • Multiple layers of different resolutions • Each layer has 4 times the number of vertices of the layer above it • Each layer contains every vertex of the layer above it

  10. Point placement • n points randomly placed on the surface • Repulsion between the points spaces them evenly • These points are now fixed in place, representing level m of an m-level mesh • Repeated for each layer, adding 3 times more points each time (3n, 12n, etc)

  11. Connectivity • Connectivity between vertices of each layer • Delaunay triangulation applied • Mesh is connected in a web of triangles

  12. Mesh hierarchy operations • Interpolation • Low-pass filtering • Downsampling • Upsampling

  13. Process • Create a mesh hierarchy over the model • Set up a vector field over the mesh • Calculate sweep distance for each vertex • Assign colors based on neighbors

  14. Vector field • Provides order to the placement of the texture on the model • Each mesh vertex is given a vector • User initiates the process by defining a few key vectors (~12)

  15. Vector field creation • All vertices not user-defined set to 0 • User-defined vectors are downsampled to the coarsest mesh • Low-pass filtering to fill out top mesh • Upsample for each layer to fill to bottom

  16. Process • Create a mesh hierarchy over the model • Set up a vector field over the mesh • Calculate sweep distance for each vertex • Assign colors based on neighbors

  17. Surface sweeping • Uses the directional flow of the vector field to assign ordering to the vertices • Ordering will allow a sort of raster scan over the 3D model • The color in the image cycles as the sweep distance increases

  18. Sweep distance calculation • Select an anchor point to base the distance • Each vertex takes the value that is the weighted sum of what its neighbors think • Distance along the flow direction added to the neighbor’s sweep distance • Sweep distances will propagate out from the anchor until every vertex has one

  19. Process • Create a mesh hierarchy over the model • Set up a vector field over the mesh • Calculate sweep distance for each vertex • Assign colors based on neighbors

  20. Pixel Neighborhoods • Similar technique to 2D texture synthesis • Examine nearby colors and look for a similar pattern in the texture image • Different kinds of pixel neighborhoods

  21. Mesh coordinate space • Pixel neighborhoods don’t translate directly to the unorganized vertices in a mesh • Vertex vector is down • Rotate 90 degrees CCW for right

  22. Multi-level synthesis • Start at top, work down • Initialize the vertices of mesh layer k with color values from Gaussian pyramid layer k • Make a pass with the half square • Top layer should have a crude representation of the texture

  23. Multi-level synthesis • Extrapolate and refine each lower level • Extrapolate initializes the colors using a large full square neighborhood of the level above • Refine improves on that by combining a large full square on the current level with a small full square on the level above

  24. Algorithm

  25. Results

  26. Results

  27. Results

  28. Results

  29. Results

  30. Results

More Related