Texture Resampling While Ray-Tracing: Approximating the Convolution Region Using Caching

We present a cache-based approach to handling the difficult problem of performing visually acceptable texture resampling/filtering while ray-tracing. While many good methods have been proposed to handle the error introduced by the ray-tracing algorithm when sampling in screen space, handling this error in texture space has been less adequately addressed. Our solution is to introduce the Convolution Mask Approximation Module (CMAM). The CMAM locally approximates the convolution region in texture space as a set of overlapping texture triangles by using a texture sample caching system and ray tagging. Since the caching mechanism is hidden within the CMAM, the ray-tracing algorithm itself is unchanged while achieving an adequate level of texture filtering (area sampling as opposed to point sampling/interpolation in texture space). The CMAM is easily adapted to incorporate prefiltering methods such as MIP mapping and summed-area tables as well as direct convolution methods such as elliptical weighted average filtering

National Bureau of Standards Reports

"The definition of color, as a characteristics of light, and the basic principles of its measurement are given. The reduction of spectrophotometric data to three chromaticity coordinates by means of the three-function CIE standard observer system for colorimetry is described. Various methods of direct colorimetry, and visual and photoelectric methods of colorimetry by differences from material standards are treated" (p. 1)

Instrumental color measurement of retroreflective highway sign materials. Final report.

Federal Highway Administration, Office of Research, Washington, D.C.Mode of access: Internet.Author corporate affiliation: National Bureau of Standards, Washington, D.C.Subject code: HBCSubject code: HBDSubject code: NDCSubject code: NDGSubject code: RCGESubject code: W

Instrumental colorimetry of retroreflective sign materials. Final report.

Federal Highway Administration, Office of Research and Development, Washington, D.C.Mode of access: Internet.COP: 2Author corporate affiliation: National Bureau of Standards, Washington, D.C.Originally dated Aug 1974. Report covers the period Dec 1972 to Aug 1974Subject code: CISubject code: LCBSubject code: LCCSubject code: NDCSubject code: NDGSubject code: WOGBSubject code: WU*NDSubject code: X

Rendering spaces for architectural environments

We present a new framework for rendering virtual environments. This framework is proposed as a complete scene description, which embodies the space of all possible renderings, under all possible lighting scenarios of the given scene. In effect, this hypothetical rendering space includes all possible light sources as part of the geometric model. While it would be impractical to implement the general framework, this approach does allow us to look at the rendering problem in a new way. Thus, we propose new representations that are subspaces of the entire rendering space. Some of these subspaces are computationally tractable and may be carefully chosen to serve a particular application. The approach is useful both for real and virtual scenes. The framework includes methods for rendering environments which are illuminated by artificial light, natural light, or a combination of the two models.

Rendering Spaces for Architectural Environments

We present a new framework for rendering virtual environments. This framework is proposed as a complete scene description, which embodies the space of all possible renderings, under all possible lighting scenarios of the given scene. In effect, this hypothetical rendering space includes all possible light sources as part of the geometric model. While it would be impractical to implement the general framework, this approach does allow us to look at the rendering problem in a new way. Thus, we propose new representations that are subspaces of the entire rendering space. Some of these subspaces are computationally tractable and may be carefully chosen to serve a particular application. The approach is useful both for real and virtual scenes. The framework includes methods for rendering environments which are illuminated by artificial light, natural light, or a combination of the two models. 1 Introduction The emerging field of visualization in computer science combines calculations with c..

Precision measurement and calibration : selected NBS papers on colorimetry /

Includes bibliographical references.Mode of access: Internet