Abstract: A plurality of identical rendering pipelines are connected in parallel to read an array of voxels and to write an array of pixels. Each pipeline processes one voxel in one processing cycle of the pipelines. Each pipeline includes a plurality of serially connected different stages. The stages can include interpolation, classification, gradient estimation, illumination, and compositing stages. Interfaces connect identical stages in adjacent pipelines as one-way rings to communicate information associated with spatially adjacent voxels, and delay buffers connected parallel to particular stages communicate information associated with temporally adjacent voxels.

Abstract: A volume rendering integrated circuit includes a plurality of interconnected pipelines having stages operating in parallel. The stages of the pipelines are interconnected in a ring, with data being passed in only one direction around the ring. The volume integrated circuit also includes a render controller for controlling the flow of volume data to and from the pipelines and for controlling rendering operations of the pipelines. The integrated circuit may further include interfaces for coupling the integrated circuit to various storage devices and to a host computer.

Abstract: Reflection intensities of volume samples of a volume are mapped in a rendering pipeline by determining a reflection vector from a gradient vector associated with a sample and an eye vector associated with the volume. A diffuse reflectance map is indexed by the gradient vector to obtain a diffuse intensity. A specular reflection map is indexed by the gradient vector to obtain a specular intensity in response to a bypass signal being true, and a specular reflection map is indexed by the reflection vector to obtain the specular intensity in response to the bypass signal being false.

Abstract: A volume rendering pipeline includes a plurality of processing stages such as a gradient estimation stage, an interpolation stage, a classification stage, an illumination stage, and a compositing stage. The stages are connected to each other by multiplexers. A first multiplexer connects an output of a first stage to an input of a second stage. A second multiplexer connects an output of the second stage to an input of the first stage. A third multiplexer has inputs connected to the output of the first stage and the output of the second stage, the first, second, and third multiplexers are responsive to a select signal to configure the stages of the rendering pipeline for processing the volume data set.

Abstract: Samples of a volume are lighted in a rendering pipeline by having a first arithmetic unit combine a modulated emissive coefficient with a modulated diffuse coefficient and a modulated diffuse intensity. A second arithmetic logic unit combines a specular coefficient with a modulated specular intensity and an opacity component of the sample. A third arithmetic unit combines the output of the second arithmetic logic unit and specular colors of the sample. A fourth arithmetic logic unit combines the output of the first arithmetic unit with colors of the sample, and a fifth arithmetic logic unit combines the output of the third and fourth arithmetic units to illuminate the sample.

Abstract: A volume data set having voxels arranged according to an object coordinate system is shear-warp rendered by partitioning, relative to the object coordinate system, the volume data set into a plurality of axis aligned sets of voxels. The selected axis aligned sets of voxels are rendered as pixels in intermediate baseplanes. There is one intermediate baseplane for each selected set of axis aligned voxels. The intermediate baseplanes are combined and warped to an image.

Abstract: A method modulates volume samples in an illumination stage of a volumetric rendering pipeline. The method determines a magnitude of a gradient vector of a volume sample. The gradient vector has components Gu″ Gu′ and Gw. The squares of the components are summed to determine a squared gradient magnitude |G2|. The square root of the squared magnitude |G2| is taken to determine the magnitude |G| of the gradient vector. A step value in a gradient magnitude range is then specified. A high pass modulation factor is set to zero if the magnitude is less than the step value, and to one otherwise to modulate the volume sample with a step function.

Abstract: A method modulates samples in a volume rendering pipeline by storing modulation values as entries in a table. Also stored are a grain and a base for the entries of the table to specify an index range. A magnitude of a gradient vector of a sample is determined. The table is indexed using the magnitude to determine two modulation values corresponding to the magnitude. The two modulation values are interpolated using the grain and the base to determine a modulation factor to modulate the sample with a linear function.

Abstract: An apparatus generates lighting modulation factors for samples in a volume rendering pipeline. The apparatus includes a first arithmetic logic unit squaring a gradient magnitude vector of a sample to produce a squared gradient magnitude. A second arithmetic logic unit produces a gradient magnitude from the squared gradient magnitude. A shift register, connected to the first arithmetic logic unit, truncates a predetermined number of high bits of the squared gradient magnitude. A gradient magnitude modulation register stores modulation parameters. A first multiplexer, connected to the second arithmetic logic unit and the shift register, selects the truncated squared gradient magnitude as an index if an index source signal is true, and the gradient magnitude if the index source signal is false, and a memory table is indexes by the index to produce modulated opacity, emissive, diffuse and specular modulation factors.

Abstract: An apparatus illuminates samples in a volume rendering pipeline. The apparatus includes the following units. A gradient magnitude modulation unit produces an opacity, emissive, diffuse and specular modulation factor from a gradient magnitude vector of each sample. A reflectance mapping unit produces a diffuse intensity and a specular intensity from the gradient magnitude vector of each sample and an eye vector of the volume. A first arithmetic logic unit combines an opacity of each sample with the corresponding opacity modulation factor to generate modulated opacities. A second arithmetic logic unit combines an emissive coefficient with the emissive modulation factor of each sample to generate modulated emissive coefficients. A third arithmetic logic unit combines the diffuse intensity with the diffuse modulation factor of each sample to generate modulated diffuse intensities.

Abstract: A computer graphics system renders an image on a display device using improved pre-filtering techniques that minimize aliasing artifacts in the image, particularly at the endpoints of lines. To anti-alias the image, a plurality of edges are placed near a line in the image. An edge function represents the edge. This edge function is multiplied by a scale factor to produce a distance function. This scale factor is the reciprocal of the Euclidean length of the line. The distance function is evaluated to determine the distance of selected pixels from each edge in units of pixels. These distances determine the intensity value for each selected pixel. Pixels on or beyond an edge, with respect to the line, are given a minimum intensity value; pixels inside all edges are given intensity values corresponding to their distances from the edge. An intensity function describing a relationship between pixel distances from the edges and their corresponding intensity values is developed.