Generalized wavelet product integral for rendering dynamic glossy objects

We consider real-time rendering of dynamic glossy objects with realistic shadows under distant all-frequency environment lighting. Previous PRT approaches pre-compute light transport for a fixed scene and cannot account for cast shadows on high-glossy objects occluded by dynamic neighbors. In this paper, we extend double/triple product integral to generalized multi-function product integral. We represent shading integral at each vertex as the product integral of multiple functions, involving the lighting, BRDF, local visibility and dynamic occlusions. Our main contribution is a new mathematical representation and analysis of multi-function product integral in the wavelet domain. We show that multi-function product integral in the primal corresponds to the summation of the product of basis coefficients and integral coefficients. We propose a novel generalized Haar integral coefficient theorem to evaluate arbitrary Haar integral coefficients. We present an efficient sub-linear algorithm to render dynamic glossy objects under time-variant all-frequency lighting and arbitrary view conditions in a few seconds on a commodity CPU, orders of magnitude faster than previous techniques. To further accelerate shadow computation, we propose a Just-in-time Radiance Transfer (JRT) technique. JRT is a new generalization to PRT for dynamic scenes. It is compact and flexible, and supports glossy materials. By pre-computing radiance transfer vectors at runtime, we demonstrate rendering dynamic view-dependent all-frequency shadows in real-time. Copyright © 2006 by the Association for Computing Machinery, Inc

Evaluation of color prediction models in the decoration of ceramic tiles

The manufacturing of ceramic tiles is a very complex process, where a wide range of variables has an important influence in the final product. With regard to external appearance, the most of the production defects take place in the decoration station. Nevertheless, these defects are usually detected before baking, when the product is already finished, causing an important loss of effectives. Under this perspective, a mechanism able to detect the printing defects in the green parts would archieve 2 goals: on one hand, the reductions of the nonquality consts since green parts can be more easily recycled; and on the other hand, it would point out the real root cause of the failure by indicating, for instance, which ink is causing the problem. Color Prediction Models (CPM) are mathematical approaches which relate the microscopic distribution of the printed dots of a halftone image withe the resulting macroscopic color. It usage is extended in the field of Graphic Arts, especially for calibration and fine image reproduction. However, they are barely known in the ceramic tile industry, a sector that keeps many similarities with the Graphic Arts one in terms of decorating. In this paper, we analyzed the prediction quality of 4 succesful CPM (Murray-Davies, Yule-Nielsen, Neugebauer an Neugebauer Modified Yule-Nielsen) on 1 and 2 inks halftones printed on ceramic substrates, setting a comparison between them by means of linear and non-linear optimization techniques. Moreover, we proposed a value for the enigmatic "n" parameter on ceramic surfaces, which is said to model the optical dot gain phenomenon

Precomputed local radiance transfer for real-time lighting design

This paper introduces a new method for real-time relighting of scenes illuminated by local light sources. We extend previous work on precomputed radiance transfer for distant lighting to local lighting by introducing the concept of unstructured light clouds. The unstructured light cloud enables a compact representation of local lights in the model and real-time rendering of complex models with full global illumination due to local light sources. We use simplification of lights, and clustered PCA to obtain a compressed representation. When storing only the indirect component of the illumination, we are able to get high quality with only 8-16 lighting coefficients per vertex. Our results demonstrate real-time rendering of scenes with moving lights, dynamic cameras, glossy materials and global illumination

Perspectives on an integrated construction project model

This paper reviews the growing interest in an integrated construction project model, and examines the fundamental concept of an integrated project model by discussing the various definitions that have evolved as well as the various approaches to its development. The nature of collaborative communications that the integrated project model needs to support is also discussed, as are the enabling information and communications technologies that may have a role in the realization of the model. The paper concludes with some thoughts on the future development of the integrated construction project model