摘要:
Techniques are described for rendering a volume of scattering media, in particular by computing radiances of points or voxels in the scattering media. A set of sample points in the scattering media are found. Radiances of the sample points are computed. Radiance gradients of the sample points are computed from the radiances. The radiances and gradients are used to interpolate radiances throughout the scattering media. The set of sample points may be computed in an iterative dynamic manner in order to concentrate samples near features (e.g., shadow edges) of the scattering media.
摘要:
A method, device and system is provided for providing global illumination of a scene. For example, global illumination may be provided in a rendered 3-dimensional image that may contain objects and/or light sources. Radiance functions or visibility functions may further be represented by scaling of spherical harmonics functions in the spherical harmonics domain. For example, scaling of spherical harmonics coefficients corresponding to a spherical function may be performed based on a spherical harmonics scaling transformation matrix based on an angular scaling function.
摘要:
A method, device and system is provided for providing global illumination of a scene. For example, global illumination may be provided in a rendered 3-dimensional image that may contain objects and/or light sources. Radiance functions or visibility functions may further be represented by scaling of spherical harmonics functions in the spherical harmonics domain. For example, scaling of spherical harmonics coefficients corresponding to a spherical function may be performed based on a spherical harmonics scaling transformation matrix based on an angular scaling function.
摘要:
Pre-computed shadow fields are described. In one aspect, shadow fields for multiple entities are pre-computed. The shadow fields are pre-computed independent of scene configuration. The multiple entities include at least one occluding object and at least one light source. A pre-computed shadow field for a light source indicates radiance from the light source. A pre-computed shadow field for an occluding object indicates occlusion of radiance from the at least one light source.
摘要:
Removal of the effects of dust or other impurities on image data is described. In one example, a model of artifact formation from sensor dust is determined. From the model of artifact formation, contextual information in the image and a color consistency constraint may be applied on the dust to remove the dust artifacts. Artifacts may also be removed from multiple images from the same or different cameras or camera settings.
摘要:
A method for modeling a time-variant appearance of a material is described. A sample analysis of a material sample is performed, wherein the sample analysis orders surface points of the material sample with respect to weathering from data captured at a single instant in time. An appearance synthesis using the sample analysis is performed, wherein the appearance synthesis generates a time-variant sequence of frames for weathering an object.
摘要:
A system and process for determining the vignetting function of an image and using the function to correct for the vignetting is presented. The image can be any arbitrary image and no other images are required. The system and process is designed to handle both textured and untextured segments in order to maximize the use of available information. To extract vignetting information from an image, segmentation techniques are employed that locate image segments with reliable data for vignetting estimation. Within each image segment, the system and process capitalizes on frequency characteristics and physical properties of vignetting to distinguish it from other sources of intensity variation. The vignetting data acquired from segments are weighted according to a presented reliability measure to promote robustness in estimation.
摘要:
Techniques are provided for at least modeling any one of mesostructure shadowing, masking, interreflection and silhouettes on a surface, as well as subsurface scattering within a non-homogeneous volume. Such techniques include, at least, acquiring material parameters for a material sample, determining irradiance distribution values for the material sample, synthesizing the material sample onto a mesh of an object. The synthesized object may then be rendered by one of plural rendering techniques.
摘要:
A “mesostructure renderer” uses pre-computed multi-dimensional “generalized displacement maps” (GDM) to provide real-time rendering of general non-height-field mesostructures on both open and closed surfaces of arbitrary geometry. In general, the GDM represents the distance to solid mesostructure along any ray cast from any point within a volumetric sample. Given the pre-computed GDM, the mesostructure renderer then computes mesostructure visibility jointly in object space and texture space, thereby enabling both control of texture distortion and efficient computation of texture coordinates and shadowing. Further, in one embodiment, the mesostructure renderer uses the GDM to render mesostructures with either local or global illumination as a per-pixel process using conventional computer graphics hardware to accelerate the real-time rendering of the mesostructures. Further acceleration of mesostructure rendering is achieved in another embodiment by automatically reducing the number of triangles in the rendering pipeline according to a user-specified threshold for acceptable texture distortion.
摘要:
A “mesostructure renderer” uses pre-computed multi-dimensional “generalized displacement maps” (GDM) to provide real-time rendering of general non-height-field mesostructures on both open and closed surfaces of arbitrary geometry. In general, the GDM represents the distance to solid mesostructure along any ray cast from any point within a volumetric sample. Given the pre-computed GDM, the mesostructure renderer then computes mesostructure visibility jointly in object space and texture space, thereby enabling both control of texture distortion and efficient computation of texture coordinates and shadowing. Further, in one embodiment, the mesostructure renderer uses the GDM to render mesostructures with either local or global illumination as a per-pixel process using conventional computer graphics hardware to accelerate the real-time rendering of the mesostructures. Further acceleration of mesostructure rendering is achieved in another embodiment by automatically reducing the number of triangles in the rendering pipeline according to a user-specified threshold for acceptable texture distortion.