Patents by Inventor Andrew C.-H. Woo

Andrew C.-H. Woo has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8217939
    Abstract: A method is provided for calculating edge normals when transforming 3D geometric data (e.g., polygon mesh data) to voxel data, which includes four steps. First, each geometric unit (e.g., each polygon) in the 3D geometric data is mapped to a voxel grid. Second, edge voxels are detected in the voxel grid. As used herein, an edge voxel means a voxel forming an edge of an object to be rendered. Third, for each edge voxel, one or more normals of the one or more geometric units that intersect with that edge voxel are calculated and stored. Fourth, for each edge voxel, an edge normal is obtained by combining (e.g., equal-weight-averaging) the one or more normals stored in association with that edge voxel.
    Type: Grant
    Filed: October 17, 2008
    Date of Patent: July 10, 2012
    Assignee: NGRAIN (Canada) Corporation
    Inventors: Claudia Bonciu, Andrew C. -H. Woo
  • Patent number: 7218323
    Abstract: A method is provided for rendering 3D voxel data including plural voxel sets, while eliminating artifacts that may result from the plural voxel sets colliding with each other (“voxel interpenetration”). In one aspect, the method involves an extension of the splatting approach, and uses a z-buffer associated with each pixel to indicate the z-depth of a voxel to be painted onto the pixel. According to the method, first, the z-buffer for each pixel is reset (cleared). Next, for each of the plural voxel sets, one voxel set at a time (sequentially), voxels within the voxel set are traversed until an occupied voxel is found. If a z value of the occupied voxel is less than a z value stored in the z-buffer, the z value of the occupied voxel is stored in the z-buffer and the occupied voxel is painted onto an associated pixel. Then, the next occupied voxel is considered.
    Type: Grant
    Filed: August 13, 2004
    Date of Patent: May 15, 2007
    Assignee: NGrain (Canada) Corporation
    Inventors: Paul A. Halmshaw, Andrew C.-H. Woo, Lev N. Gretskii, Jonathan M. Young
  • Patent number: 6867774
    Abstract: A method and apparatus are provided for transforming 3D geometric data, such as polygon data (16) formed of polygons (18), into volumetric data (14) formed of voxels (12). According to the method, 3D geometric data to be converted to voxel data are acquired, and the resolution of a final voxel grid to be produced is obtained (e.g., user-defined). Then, each geometric unit (e.g., a polygon) in the 3D geometric data is mapped (or scan converted) to an imaginary voxel grid having a higher resolution than the resolution of the final voxel grid. Next, with respect to the geometric units that are mapped to the imaginary voxels in the imaginary voxel grid dividing one final (actual) voxel into smaller sub-volumes, a weighted average of the attribute values (color, normal, intensity, etc.) is obtained. The weighted average is stored as the attribute value of the final voxel.
    Type: Grant
    Filed: December 2, 2002
    Date of Patent: March 15, 2005
    Assignee: NGRAIN (Canada) Corporation
    Inventors: Paul A. Halmshaw, Jonathan M. Young, Andrew C.-H. Woo