Abstract: A method for performing direct rendering of a multi-volume data, having the steps of determining whether a volume of the multi-volume data is one of active and inactive via interaction with a ray for the multi-volume data, recording in triplicate a starting point and an end point of the ray for an eyespace, repeating the determining whether the volume is one of active and inactive via interaction with a ray for the multi-volume data and the recording in triplicate a starting point and an end point of the ray for an eyespace for all volumes of the multi-volume data, providing triples from all volumes to an array, sorting the array to create a sorted triples list array, breaking the ray into a plurality of segments using the sorted triples list array, determining which volumes are active for each of the segments via an active volume list, and sampling each segment of the ray to acquire an accumulated result.

Abstract: A method for rendering a volumetric image includes providing a digitized volumetric image comprising a plurality of intensities corresponding to a domain of points in a 3-dimensional space, casting a ray through said volumetric image for a first pass to determine a threshold intensity for said ray, casting said ray through said volumetric image for a second pass, and sampling only those points whose intensity value is selected by said threshold intensity to determine a rendering value for said ray, wherein said rendering value is associated with a pixel from which said ray was cast.

Abstract: A system and method for rendering an MIP image that has reduced high frequency component loss and reduced chessboard artifacts. The method includes accessing volumetric data, having random noise. Rays are shot, or cast, through the volumetric data, onto a voxel grid, which has grid points. Sampling data along each ray is performed to obtain selected sample data points on the ray and a distance from a selected point to a nearest grid point is determined. A voxel intensity value is accessed at each selected point, as a function of the position of the selected point relative to the nearest grid point. The difference between the voxel intensity at each selected point is minimized an image is rendered from the volumetric data as a function of the minimizing step. Multiple methods may be used to minimize the difference between the voxel intensity at each selected point. These include for example 1.) applying a localized low pass filter, 2.) applying a localized high order interpolation kernel, and 3.

Abstract: A system and methods for volume rendering using n-pass sampling are disclosed. A plurality of first rays in a first density is sampled through a volume. Each of the first rays is in a separate section. A value of at least one first ray is compared to a first threshold. A plurality of second rays in a second density is sampled based on the comparison of the at least one first ray. The second rays are in a first section of the separate sections. The first section being for the at least one first ray. A value of at least one second ray is compared to a second threshold. A plurality of third rays is sampled in a second section spatially different than the first section based on the comparison of the at least one second ray. An image rendered from the sampling of at least the first rays is displayed.

Abstract: A system and method for rendering an image that includes accessing image data and dividing the image data into one or more blocks. One or more corner points of the blocks are identified and rays are cast through voxel space of the image data in the direction of the corner points to determine one or more integrated values for the corner points. The integrated values are then sampled and compared to the sampled values for each combination of the corner points. A difference value (diffvalue) is calculated as a function of the comparison and an initial gradient (grad) is calculated as a function of a Reduced Path Octree (RPO) structure during the casting of rays. Next, a maximum gradient (maxGrad) is calculated based on the initial gradient (grad). Finally, an image processing operation is determined as a function of the maximum gradient (maxGrad) and the difference value (diffvalue).

Abstract: A method and system of increasing the speed of a ray-casting algorithm for producing direct volume rendering images in the melt-through interaction mode. Since the viewing direction is not changed during a melt-through interaction, it is possible to reuse the samples calculated along each ray from one frame to another. The samples along each ray are partitioned into different groups, and the samples within each partition can be composited to generate an RGBA-tuple (Red Green Blue and Alpha, which is an opacity factor) for the partition. The associative property of the composition operation allows computation of the final RGBA value for each ray by compositing the RGBA-values of the partitions, instead of compositing the RGBA-values of each sample along the ray.

Abstract: A system and method of determining a sampling rate for rendering a volumetric image, the method includes determining a regional variation value representing regional data, color, and/or alpha variation. An accumulated opacity value is determined that represents opacity accumulated over a ray in the image, and a regional opacity value is determined that represents regional opacity. A quality setting is accessed that represents a default image quality, and the sampling rate is adjusted as a function of the regional variation value, the accumulated opacity value, the regional opacity value, and the quality setting. The regional variation value may be determined by iteratively generating a maximum regional variation table during pre-processing, quantizing the maximum regional variation table where the transfer function is defined based on a histogram of the volumetric image, and computing the regional variation value using the maximum regional variation table.

Abstract: A computer-implemented method for intensity projection includes providing volume data, determining an estimated threshold for determining a maximum/minimum intensity value in the volume data from temporal coherence and spatial coherence information, performing the second pass for determining an actual maximum/minimum value along the new ray, wherein the second pass uses the estimated threshold as an initial threshold, and updating the buffer with a new location value where the actual maximum/minimum value for the next frame was determined.

Abstract: A method of propagating a ray through an image includes providing a digitized volumetric image comprising a plurality of intensities corresponding to a domain of voxels in a 3-dimensional space, providing a reduced path octree structure of said volumetric image, said reduced path octree comprising a plurality of first level nodes, wherein each first level node contains a plurality of said voxels, initializing a ray inside said volumetric image, and visiting each first level node along said ray, wherein if said first level node is non-empty, visiting each voxel contained within each first level node.

Abstract: An apparatus and method are provided for providing efficient space leaping using neighbor guided emptiness map in octree traversal for fast ray casting. The apparatus and method include providing a min-max octree structure, marching a ray through the min-max structure; and skipping empty nodes associated with the min-max structure along the direction of the ray based on a memory byte included in each node comprising an emptiness state of neighbor nodes and a current node.

Abstract: A computer-implemented method for intensity projection includes providing volume data, determining an estimated threshold for determining a maximum/minimum intensity value in the volume data from temporal coherence and spatial coherence information, performing the second pass for determining an actual maximum/minimum value along the new ray, wherein the second pass uses the estimated threshold as an initial threshold, and updating the buffer with a new location value where the actual maximum/minimum value for the next frame was determined.

Abstract: A method of propagating a ray through an image includes providing a digitized volumetric image comprising a plurality of intensities corresponding to a domain of voxels in a 3-dimensional space, providing a reduced path octree structure of said volumetric image, said reduced path octree comprising a plurality of first level nodes, wherein each first level node contains a plurality of said voxels, initializing a ray inside said volumetric image, and visiting each first level node along said ray, wherein if said first level node is non-empty, visiting each voxel contained within each first level node.

Abstract: A method for rendering a volumetric image includes providing a digitized volumetric image comprising a plurality of intensities corresponding to a domain of points in a 3-dimensional space, casting a ray through said volumetric image for a first pass to determine a threshold intensity for said ray, casting said ray through said volumetric image for a second pass, and sampling only those points whose intensity value is selected by said threshold intensity to determine a rendering value for said ray, wherein said rendering value is associated with a pixel from which said ray was cast.