The Cleveland Clinic Foundation

Dreamworks Animation LLC

Hewlett-packard Company

Donald P Greenberg

Roy K Greenberg

Vikash Ravi Goel

Philip McNally

Matthew Low

Eric A Haines

Michael F Cohen

A computer implemented method for determining a centerline of a three-dimensional tubular structure is described. The method includes providing an edge-detected data set of voxels that characterize a boundary of the tubular structure according to a three-dimensional voxel data set for the tubular structure. A gradient field of a distance transformation is computed for the edge-detected dataset. A voxel data set corresponding to a centerline of the tubular structure is computed according to derivative of gradient field. A trajectory within the tubular structure is computed based on the centerline.

Automated centerline extraction method for determining trajectory

A computer implemented method for determining a centerline of a three-dimensional tubular structure is described. The method includes providing an edge-detected data set of voxels that characterize a boundary of the tubular structure according to a three-dimensional voxel data set for the tubular structure. A gradient field of a distance transformation is computed for the edge-detected dataset. A voxel data set corresponding to a centerline of the tubular structure is computed according to derivative of gradient field.

Automated centerline extraction method and generation of corresponding analytical expression and use thereof

A computer-implemented method for computing an effective inter-ocular distance for a modeled viewer based on a maximum ocular divergence angle. A maximum ocular divergence angle, viewing distance, and an inter-ocular distance are obtained for the modeled viewer. An effective inter-ocular distance is computed based on the viewing distance, the inter-ocular distance, and the maximum ocular divergence angle. The effective inter-ocular distance represents the maximum positive parallax for the modeled viewer having the defined maximum ocular divergence angle. The effective inter-ocular distance may be used in a stereoscopic modeling system in place of the inter-ocular distance, the stereoscopic modeling system relating a set of parameters in a camera space to a set of parameters in viewer space. The stereoscopic modeling system may be a stereoscopic transformation.

Stereoscopic modeling based on maximum ocular divergence of a viewer

A computer-implemented method for measuring the stereoscopic quality of a computer-generated object in a three-dimensional computer-generated scene. The computer-generated object is visible from at least one camera of a pair of cameras used for creating a stereoscopic view of the computer-generated scene. A set of surface vertices of the computer-generated object is obtained. A stereoscopic transformation on the set of surface vertices is computed to obtain a set of transformed vertices. A translation vector and a scale vector are computed and applied to the set of transformed vertices to obtain a ghosted set of vertices. The ghosted set of vertices is approximately translational and scale invariant with respect to the set of surface vertices. A sum of the differences between the set of surface vertices and the set of ghosted vertices is computed to obtain a first stereo-quality metric.

Measuring stereoscopic quality in a three-dimensional computer-generated scene

A computer implemented method () for determining a centerline of a three-dimensional tubular structure is described. The method includes providing an edge-detected data set of voxels that characterize a boundary of the tubular structure according to a three-dimensional voxel data set for the tubular structure (). A gradient field of a distance transformation is computed for the edge-detected dataset (). A voxel data set corresponding to a centerline of the tubular structure is computed according to derivative of gradient field ().

A computer-implemented method for defining a range of bounding parameter values that satisfy perceptual constraints for a stereoscopically filmed computer-generated scene. A user selection of a bounding parameter from a set of scene parameters is selected. Values for scene parameters of the set of scene parameters that were not selected as the bounding parameter are obtained. A first bounding value for the bounding parameter is calculated based on a first perceptual constraint and based on the values of the scene parameters of the set of scene parameters that were not selected. A second bounding value for the bounding parameter is also calculated based on a second perceptual constraint and based on the values of the scene parameter of the set of scene parameters that were not selected. The first and second bounding values define a minimum and a maximum value of a range of values and are stored.

Stereoscopic computer-animation techniques based on perceptual constraints

In an algorithm for deriving radiation images, where view independent radiation calculations are precomputed so that they do not need to be repeated for every view of the same environment. To find the form factors for radiosity techniques, a hemi-cube is constructed around the surface with grid cells defined for all faces on the hemi-cube. All other surfaces in the environment are projected onto the hemi-cube to facilitate the form factor calculations. A novel ray-tracing technique is disclosed where a light buffer in the form of a cube is constructed around each radiation source and grid cells are defined on the faces of the cube. Surfaces in the environment are projected onto the cube and the depths from the source are stored for each grid cell to facilitate shadow testing. Light reflected off of the viewed surface from another surface may be modeled by determining mirror positions of the viewer and the image plane. Instead of storing the depths of surfaces from the viewer or the radiation source, the identity of the polygons in the environment are stored instead to speed up the calculations. Scan conversion hardware is used to accelerate each of these operations. In a graphics pipeline, a feedback path is provided from the image processor to the CPU memory to store the result of the form factor or light buffer pre-computations to speed up the radiosity and ray-tracing calculations by several orders of magnitude.

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Ithaca, NY, United States of America

Donald P Greenberg