Abstract: A method for creating artistic effects for volumetric illumination in a scene is provided. Data representing a scene is received. User input is received, which specifies a target appearance of the scene, including illumination effects that are at least in part non-physically-based. Photon beams representing volumetric illumination in the scene are generated; this step may incorporate user input-based modifications of the photon beams. Shading associated with the photon beams is computed; this step may also incorporate user input-based modifications. Any modifications in the generating or computing steps are derived from the specified target appearance of the scene. Finally, the photon beams are rendered.

Abstract: Rendering a scene with participating media is done by generating a depth map from a camera viewpoint and a shadow map from a light source, converting the shadow map using epipolar rectification to form a rectified shadow map (or generating the rectified shadow map directly), generating an approximation to visibility terms in a scattering integral, then computing a 1D min-max mipmap or other acceleration data structure for rectified shadow map rows and traversing that mipmap/data structure to find lit segments to accumulate values for the scattering integral for specific camera rays, and generating rendered pixel values that take into account accumulated values for the scattering integral for the camera rays. The scattering near an epipole of the rectified shadow map might be done using brute force ray marching when the epipole is on or near the screen. The process can be implemented using a GPU for parallel operations.

Abstract: There is provided a system including a memory storing a software application and a processor configured to execute the software application to transmit a light through a scene, the scene including a medium described by an extinction function, define a fictitious medium described by a fictitious extinction function, determine a path through the medium, the path including a plurality of points, calculate one of a plurality of weights for each of the plurality of points, the one of the plurality of weights corresponding to one minus the ratio of the extinction function to the fictitious extinction function, and estimate a transmittance of the lights through the medium as a product of the plurality of weights.

Abstract: Techniques are described for designing and manufacturing a surface that produces a desired image when illuminated by a light source. As described, the desired image may be decomposed into a collection of Gaussian kernels (referred to as Gaussians). A shape of a micropatch lens corresponding to each Gaussian may be determined, and the resulting micropatch lenses may be assembled to form a highly continuous surface that will cast an approximation of the desired image formed form the sum of a plurality of Gaussian caustics. The disclosed techniques may be used to create a design for a light-redirecting surface amenable to milling (or other manufacturing process).

Abstract: A method for rendering radiance for a volumetric medium is provided. A photon simulation produces a representation of photon beams in a scene. The photon beams are rendered with respect to a camera viewpoint, by computing an estimated radiance associated with the photon beams. A global radius scaling factor can be applied to obtain different radii for the photon beams. Over multiple applications of these steps, the global radius scaling factor can be decreased, thereby reducing overall error by facilitating convergence. Finally, the renderer can be efficiently implemented on the GPU as a splatting operation, for use in interactive and real-time applications.

Abstract: Techniques are described for designing and manufacturing a surface that produces a desired image when illuminated by a light source. As described, the desired image may be decomposed into a collection of Gaussian kernels (referred to as Gaussians). A shape of a micropatch lens corresponding to each Gaussian may be determined, and the resulting micropatch lenses may be assembled to form a highly continuous surface that will cast an approximation of the desired image formed form the sum of a plurality of Gaussian caustics. The disclosed techniques may be used to create a design for a light-redirecting surface amenable to milling (or other manufacturing process).

Abstract: Techniques for displaying content using an augmented reality device are described. Embodiments provide a visual scene for display, the visual scene captured using one or more camera devices of the augmented reality device. Embodiments adjust physical display geometry characteristics of the visual scene to correct for optimal projection. Additionally, illumination characteristics of the visual scene are modified based on environmental illumination data to improve realism of the visual scene when it is displayed. Embodiments further adjust display characteristics of the visual scene to improve tone mapping output. The adjusted visual scene is then output for display on the augmented reality device.

Abstract: State-of-the-art density estimation methods for rendering participating media rely on a dense photon representation of the radiance distribution within a scene. A parametric density estimation technique is used to represent radiance using a hierarchical Gaussian mixture. Coefficients of this mixture are efficiently obtained for use in a progressive and accelerated form of the Expectation-Maximization algorithm. Noise-free renderings of high-frequency illumination are created using only a few thousand Gaussian terms, where millions of photons are traditionally required. Temporal coherence is trivially supported within this framework, and the compact footprint is also useful in the context of real-time visualization. A hierarchical ray tracing-based implementation is demonstrated, as well as a fast splatting approach that can interactively render animated volume caustics.

Abstract: Techniques are described for designing and manufacturing a refractive surface that produces a desired image when placed over a target image. The refractive lens surface may include a set of lens patches, each of which indexes a region on the source image to refract light from the indexed region to recreate a patch of the target image. And together, the lenses reproduce the target image. In one embodiment, the refractive geometry of the lens surface (i.e., the shape of each lens) is determined by formulating and efficiently determining a solution to an inverse light transport problem. The solution may account for additional constraints imposed by the physical manufacturing procedure. Doing so results in a design for a refractive surface amenable to milling (or other manufacturing process).

Abstract: Methods and systems of joint path importance sampling are provided to construct light paths in participating media. The product of anisotropic phase functions and geometric terms across a sequence of path vertices are considered. A connection subpath is determined to join a light source subpath with a light receiver subpath with multiple intermediate vertices while considering the product of phase functions and geometry terms. A joint probability density function (“PDF”) may be factorized unidirectional or bidirectional. The joint PDF may be factorized into a product of multiple conditional PDFs, each of which corresponds to a sampling routine. Analytic importance sampling may be performed for isotropic scattering, whereas tabulated importance sampling may be performed for anisotropic scattering.

Abstract: The disclosure provides an approach for rendering granular media. According to one aspect of the disclosure, granular media are rendered using bidirectional point scattering distribution functions (BPSDFs). The dimensionality of BPSDFs may be reduced by making certain assumptions, such as random orientations of grains, thereby simplifying light transport for computational efficiency. To generate a BPSDF from a grain, light transport may be precomputed using a Monte Carlo simulation in which photons are shot onto the grain from all directions. The precomputed BPSDF may be used, during rendering, for describing the interactions within grains. When a light ray traced during rendering intersects proxy geometry which replaces grain geometry, the BPSDF may be evaluated to determine light transport. By repeating this process for many light rays in a Monte Carlo simulation, the light propagation through the granular medium may be determined.

Abstract: An efficient numerical method for accurately rendering translucent materials using photon beam diffusion is provided that can account for multilayer materials and directional incident and exitant effects at the surface. In an embodiment, refracted incident light is represented continuously as a photon beam instead of as discrete photons. An integration scheme for calculating a radiant exitance value at a point on the surface of the translucent material is disclosed that uses importance sampling and evaluates a radiant function at a limited number of points along the beam.

Abstract: A method for creating a replication material corresponding to the appearance of a translucent or partially translucent target material. The appearance of the target material can be measured or may be prescribed by a user. The method includes receiving by a processor optical data related to a target subsurface scattering parameter of the target material. Once the processor has received the optical or light characteristic data, the method includes determining by the processor a replication pigment concentration to replicate the appearance of the target material caused by the target subsurface scattering parameter. The processor determines this concentration based on a plurality of pigment subsurface scattering parameters corresponding to a plurality of stored pigment concentrations in the computing device. Once the replication pigment concentration has been determined, the method includes creating, physically or virtually, the replication material by combining the pigment concentration with a base material.

Abstract: The disclosure provides an approach for determining, in 3D rendering, the integrals of visibility-masked spherical functions using visibility silhouettes. For a given shade point, the visibility silhouette for that shade point includes a set of edges from the scene geometry which form the boundaries between visible and invisible regions of a hemisphere having the shade point as its center. For each shade point, a rendering application determines a set of contour edges of scene geometry, the contour edges being a superset of the set of visibility silhouette edges, by querying a 4D dual mesh. The rendering application then evaluates the integral of the visibility-masked spherical function for a given shade point by integrating over segments of discrete u-isolines for which an overlap function indicates that a ray from the shade point would not intersect scene geometry.

Abstract: A method and system for progressively rendering radiance for a volumetric medium is provided. A photon simulation produces a representation of photon beams in a scene. The photon beams are rendered with respect to a camera viewpoint, by computing an estimated radiance associated with the photon beams. A global radius scaling factor is applied to the photon beams. Over multiple iterations of these steps, the global radius scaling factor is progressively decreased, thereby reducing overall error by facilitating convergence. This order can be mixed up. Finally, the renderer can be efficiently implemented on the GPU as a splatting operation, for use in interactive and real-time applications.

Abstract: Techniques are disclosed for performing image space reprojection iteratively. An insignificant parallax threshold depth is computed for a source image. Portions of the image having depth values greater than the insignificant parallax threshold depth may be shifted uniformly to produce corresponding portions of the reprojection (target) image. An iterative fixed-point reprojection algorithm is used to reproject the portions of the source image having depth values less than or equal to the insignificant parallax threshold depth. The fixed point reprojection algorithm quickly converges on the best pixel in the source image for each pixel in a target image representing an offset view of the source image. An additional rendering pass is employed to fill disoccluded regions of the target image, where the reprojection algorithm fails to converge.

Abstract: Projection systems and methods handle images to be viewable on a concave surface, wherein the projected image is modified to account for surface-to-surface reflections due to the concave surface, by determining geometric surface parameters, determining the ideal image, determining a model for reflected light that is a result of surface-to-surface reflections given the ideal image, wherein the model is expressible in closed form, determining a compensation image to compensate for at least some of the surface-to-surface reflections, taking into account at least the ideal image and the reflected light, and combining the compensation image and the ideal image to form a projectable image that can be projected onto a surface having the determined geometric parameters. The surface can be defined by a portion of an interior of a sphere and the reflection of a given pixel can be modeled as a constant over the concave surface.

Abstract: Techniques are described for designing and manufacturing a refractive surface that produces a desired image when placed over a target image. The refractive lens surface may include a set of lens patches, each of which indexes a region on the source image to refract light from the indexed region to recreate a patch of the target image. And together, the lenses reproduce the target image. In one embodiment, the refractive geometry of the lens surface (i.e., the shape of each lens) is determined by formulating and efficiently determining a solution to an inverse light transport problem. The solution may account for additional constraints imposed by the physical manufacturing procedure. Doing so results in a design for a refractive surface amenable to milling (or other manufacturing process).

Abstract: An analytical method to efficiently convert a function that is stored in spherical harmonics into a function that is stored in a wavelet or mip map representation enables a variety of computer graphics functions to be efficiently performed. A function may be stored as a spherical harmonic representation and rotated in the spherical harmonic domain; the function can then be converted to a wavelet representation. The conversion method may be used to convert a spherical harmonic function to wavelets, and then an importance sampling technique may be applied to the wavelet representation to generate a set of importance samples for the function. The conversion method may be applied to convert a spherical harmonic representation into the wavelet domain, and an importance sampling technique may then be applied which samples the product of the function and another function in the wavelet domain.

Abstract: Techniques are described for designing and manufacturing a surface that produces a desired image when illuminated by a light source. As described, the desired image may be decomposed into a collection of Gaussian kernels (referred to as Gaussians). A shape of a micropatch lens corresponding to each Gaussian may be determined, and the resulting micropatch lenses may be assembled to form a highly continuous surface that will cast an approximation of the desired image formed form the sum of a plurality of Gaussian caustics. The disclosed techniques may be used to create a design for a light-redirecting surface amenable to milling (or other manufacturing process).