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In this paper, we explore a novel idea of using high dynamic range (HDR) technology for uncertainty visualization. We focus on scalar volumetric data sets where every data point is associated with scalar uncertainty. We design a transfer function that maps each data point to a color in HDR space. The luminance component of the color is exploited to capture uncertainty. We modify existing tone mapping techniques and suitably integrate them with volume ray casting to obtain a low dynamic range (LDR) image. The resulting image is displayed on a conventional 8-bits-per-channel display device. The usage of HDR mapping reveals fine details in uncertainty distribution and enables the users to interactively study the data in the context of corresponding uncertainty information. We demonstrate the utility of our method and evaluate the results using data sets from ocean modeling.

Ray–based representations can model complex light transport but are limited in modeling diffraction effects that require the simulation of wavefront propagation. This paper provides a new paradigm that has the simplicity of light path tracing and yet provides an accurate characterization of both Fresnel and Fraunhofer diffraction. We introduce the concept of a light field transformer at the interface of transmissive occluders. This generates mathematically sound, virtual, and possibly negative-valued light sources after the occluder. From a rendering perspective the only simple change is that radiance can be temporarily negative. We demonstrate the correctness of our approach both analytically, as well by comparing values with standard experiments in physics such as the Young’s double slit. Our implementation is a shader program in OpenGL that can generate wave effects on arbitrary surfaces.

In this paper, we present a new method for bidirectional relighting for 3D-aided 2D face recognition under large pose and illumination changes. During subject enrollment, we build subject-specific 3D annotated models by using the subjects' raw 3D data and 2D texture. During authentication, the probe 2D images are projected onto a normalized image space using the subject-specific 3D model in the gallery. Then, a bidirectional relighting algorithm and two similarity metrics (a view-dependent complex wavelet structural similarity and a global similarity) are employed to compare the gallery and probe. We tested our algorithms on the UHDB11 and UHDB12 databases that contain 3D data with probe images under large lighting and pose variations. The experimental results show the robustness of our approach in recognizing faces in difficult situations.

It is just over 20 years since Adobe's PostScript opened a new era in digital documents. PostScript allows most details of rendering to be hidden within the imaging device itself, while providing a rich set of primitives enabling document engineers to think of final-form rendering as being just a sophisticated exercise in computer graphics. The refinement of the PostScript model into PDF has been amazingly successful in creating a near-universal interchange format for complex and graphically rich digital documents but the PDF format itself is neither easy to create nor to amend. In the meantime a whole new world of digital documents has sprung up centred around XML-based technologies. The most widespread example is XHTML (with optional CSS styling) but more recently we have seen Scalable Vector Graphics (SVG) emerge as an XML-based, low-level, rendering language with PostScript-compatible rendering semantics. This paper surveys graphically-rich final-form rendering technologies and asks how flexible they can be in allowing adjustments to be made to final appearance without the need for regenerating a whole page or an entire document. Particular attention is focused on the relative merits of SVG and PDF in this regard and on the desirability, in any document layout language, of being able to manipulate the graphic properties of document components parametrically, and at a level of granularity smaller than an entire page.

The difficulty in stepping out of the prevailing perspectival paradigm by students of design was investigated in a pedagogical exercise. It explores their ability to generate new spatial conventions. In both supporting the notion of the transference of manual perspective as a convention to digital media and offering alternatives to its seemingly reduced expression of experience beyond that of the illusion of depth alone, the exercise described in this paper goes some way towards explaining interaction with 3D media in general.

Recent research into distortion-oriented display (DODs) and non-linear magnification techniques has considered extending their application to large three-dimensional datasets. Inherent properties of three-dimensional datasets introduce some difficulties that do not occur in 2D environments. This paper considers the Occlusion Problem - that of context data hiding, or occluding, some or all of the data within an area of focus. A novel solution to this problem is proposed, namely the use of non-geometric distortions combined with geometric distortions, producing a three-dimensional distortion-oriented display that reduces obfuscation of data within the area of focus. An implementation of these techniques is developed, and its application to a small number of 3D datasets is examined as proof of concept.

Wavelength routed optical networks have emerged as a technology that can effectively utilize the enormous bandwidth of the optical fiber. Wavelength converters play an important role in enhancing the fiber utilization and reducing the overall call blocking probability of the network. As the distortion of the optical signal increases with the increase in the range of wavelength conversion in optical wavelength converters, limited range wavelength conversion assumes importance. Placement of wavelength converters is a NP complete problem in an arbitrary mesh network. In this paper, we investigate heuristics for placing limited range wavelength converters in arbitrary mesh wavelength routed optical networks. The objective is to achieve near optimal placement of limited range wavelength converters resulting in reduced blocking probabilities and low distortion of the optical signal. The proposed heuristic is to place limited range wavelength converters at the most congested nodes, nodes which lie on the long lightpaths and nodes where conversion of the optical signals is significantly high. We observe that limited range converters at a few nodes can provide almost the entire improvement in the blocking probability as the full range wavelength converters placed at all the nodes. Congestion control in the network is brought about by dynamically adjusting the weights of the channels in the link thereby balancing the load and reducing the average delay of the traffic in the entire network. Simulations have been carried out on a 12-node ring network, 14-node NSFNET, 19-node European Optical Network (EON), 30-node INET network and the results agree with the analysis.

This paper employs aerodynamic principles for the physical animation of bird flight. The wing of a bird is generated by varying aerofoil sections and overall geometrical parameters of the basic wing. The beating and other motions of the wings are specified as functions of time. The resulting trajectory of the bird is predicted by the aerodynamic and gravitational force distribution on the bird's wing. Targeting is achieved by controlling the pitching moment of the bird around its centre of gravity. Animation sequences comprising various flight phases are generated for verifying the performance of the system.

Buildings, whether adequately designed or not, develop a variety of problems over the years. The choice of an appropriate repair method requires systematic observations of the symptoms and relating them to their probable cause. Building repairs, in general, demand a high level of expertise. This paper outlines the development of REPCON?an expert system for building repairs. Evolution of elaborate knowledge nets pertaining to various building defects, using knowledge elicited from the domain expert, is discussed. These nets are then transformed into rule bases. The expert system?s metaknowledge base is used in a unique way to guide the user in the diagnostic process by means of checklists called ?proformae.? Externally activated graphics programs have been used to help the users to identify crack patterns. REPCON is intended to assist building-repair consultants and township-maintenance engineers in their day-to-day tasks. ? ASCE.

Motivated by the idea of describing parquet deformations using grammars and also of describing an infinite number of terminals starting with only a finite set, this paper defines a terminal weighted grammar, where the terminal generated at any step of a derivation is defined as a function of time. It is seen that terminal weighted regular grammars generate exactly the class of recursively enumerable sets. Terminal weighted matrix grammars are used to describe parquet deformations. The extension of terminal weights to array grammars is also discussed.