Advanced Graphics Research Articles

A 155-mW 50-m vertices/s graphics processor with fixed-point programmable vertex shader for mobile applications

A 36 mm/sup 2/ graphics processor with fixed-point programmable vertex shader is designed and implemented for portable two-dimensional (2-D) and three-dimensional (3-D) graphics applications. The graphics processor contains an ARM-10 compatible 32-bit RISC processor,a 128-bit programmable fixed-point single-instruction-multiple-data (SIMD)vertex shader, a low-power rendering engine, and a programmable frequency synthesizer (PFS). Different from conventional graphics hardware, the proposed graphics processor implements ARM-10 co-processor architecture with dual operations so that user-programmable vertex shading is possible for advanced graphics algorithms and various streaming multimedia processing in mobile applications. The circuits and architecture of the graphics processor are optimized for fixed-point operations and achieve the low power consumption with help of instruction-level power management of the vertex shader and pixel-level clock gating of the rendering engine. The PFS with a fully balanced voltage-controlled oscillator (VCO) controls the clock frequency from 8 MHz to 271 MHz continuously and adaptively for low-power modes by software. The chip shows 50 Mvertices/s and 200 Mtexels/s peak graphics performance, dissipating 155 mW in 0.18-/spl mu/m 6-metal standard CMOS logic process.

Requirements, Implementation and Applications of Hand-held Virtual Reality

While hand-held computing devices are capable of rendering advanced 3D graphics and processing of multimedia data, they are not designed to provide and induce sufficient sense of immersion and presence for virtual reality. In this paper, we propose minimal requirements for realizing VR on a hand-held device. Furthermore, based on the proposed requirements, we have designed and implemented a low cost hand-held VR platform by adding multimodal sensors and display components to a hand-held PC. The platform enables a motion based interface, an essential part of realizing VR on a small hand-held device, and provides outputs in three modalities, visual, aural and tactile/haptic for a reasonable sensory experience. We showcase our platform and demonstrate the possibilities of hand-hand VR through three VR applications: a typical virtual walkthrough, a 3D multimedia contents browser, and a motion based racing game

Low-Level Image Cues in the Perception of Translucent Materials

When light strikes a translucent material (such as wax, milk or fruit flesh), it enters the body of the object, scatters and reemerges from the surface. The diffusion of light through translucent materials gives them a characteristic visual softness and glow. What image properties underlie this distinctive appearance? What cues allow us to tell whether a surface is translucent or opaque? Previous work on the perception of semitransparent materials was based on a very restricted physical model of thin filters [Metelli 1970; 1974a,b]. However, recent advances in computer graphics [Jensen et al. 2001; Jensen and Buhler 2002] allow us to efficiently simulate the complex subsurface light transport effects that occur in real translucent objects. Here we use this model to study the perception of translucency, using a combination of psychophysics and image statistics. We find that many of the cues that were traditionally thought to be important for semitransparent filters (e.g., X-junctions) are not relevant for solid translucent objects. We discuss the role of highlights, color, object size, contrast, blur, and lighting direction in the perception of translucency. We argue that the physics of translucency are too complex for the visual system to estimate intrinsic physical parameters by inverse optics. Instead, we suggest that we identify translucent materials by parsing them into key regions and by gathering image statistics from these regions.

Visual Supercomputing: Technologies, Applications and Challenges

Abstract If we were to have a Grid infrastructure for visualization, what technologies would be needed to build such an infrastructure, what kind of applications would benefit from it, and what challenges are we facing in order to accomplish this goal? In this survey paper, we make use of the term ‘visual supercomputing’ to encapsulate a subject domain concerning the infrastructural technology for visualization. We consider a broad range of scientific and technological advances in computer graphics and visualization, which are relevant to visual supercomputing. We identify the state‐of‐the‐art technologies that have prepared us for building such an infrastructure. We examine a collection of applications that would benefit enormously from such an infrastructure, and discuss their technical requirements. We propose a set of challenges that may guide our strategic efforts in the coming years.

Actively learning computer graphics

As technology advances in computer graphics, artists are pushing the boundaries visually in video games and animation. A good way to understand what actually goes into creating even a single charac...

Advanced graphics application development with OpenGL

Do you want to make your graphics course a little more entertaining for your students? This workshop is designed to introduce advanced graphics topics that can be incorporated into an undergraduate level graphics course that teaches OpenGL. Specifically, participants will learn how to add lighting, textures, fog, picking, billboards, sound (using DirectX), and joystick input (using GLUT) to their OpenGL applications. Participants will develop a dungeon crawl game during the workshop that illustrates these concepts. Some prior C++ and OpenGL experience is required.

Computer games and CS education

Computer and video games have grown to be a major industry but, until recently, have largely been ignored by academia. The last couple of years, however, have seen the emergence of new academic programs, conferences, and journals dedicated to games studies. This panel discusses a variety of ways, and whys, for introducing games into computer science curricula. Panelists discuss their experiences in designing a broad range of courses including a games course for women, a software development course that uses games as projects, an introductory games programming course in Java, and an advanced graphics course that focuses on games.

Interactive 3-D Video Representation and Coding Technologies

Interactivity in the sense of being able to explore and navigate audio-visual scenes by freely choosing viewpoint and viewing direction, is an important key feature of new and emerging audio-visual media. This paper gives an overview of suitable technology for such applications, with a focus on international standards, which are beneficial for consumers, service providers, and manufacturers. We first give a general classification and overview of interactive scene representation formats as commonly used in computer graphics literature. Then, we describe popular standard formats for interactive three-dimensional (3-D) scene representation and creation of virtual environments, the virtual reality modeling language (VRML), and the MPEG-4 BInary Format for Scenes (BIFS) with some examples. Recent extensions to MPEG-4 BIFS, the Animation Framework eXtension (AFX), providing advanced computer graphics tools, are explained and illustrated. New technologies mainly targeted at reconstruction, modeling, and representation of dynamic real world scenes are further studied. The user shall be able to navigate photorealistic scenes within certain restrictions, which can be roughly defined as 3-D video. Omnidirectional video is an extension of the planar two-dimensional (2-D) image plane to a spherical or cylindrical image plane. Any 2-D view in any direction can be rendered from this overall recording to give the user the impression of looking around. In interactive stereo two views, one for each eye, are synthesized to provide the user with an adequate depth cue of the observed scene. Head motion parallax viewing can be supported in a certain operating range if sufficient depth or disparity data are delivered with the video data. In free viewpoint video, a dynamic scene is captured by a number of cameras. The input data are transformed into a special data representation that enables interactive navigation through the dynamic scene environment.

A word from the editor

A word from the editor

A desktop VR prototype for industrial training applications

The recent advances in computer graphics has spurred interest from both academics and industries in virtual reality (VR) enabled training applications. This paper presents a desktop VR prototype for industrial training applications. It is designed and implemented as a general shell by providing the data interface to import both the virtual environment models and specific domain knowledge. The geometric models of the virtual environment are constructed using feature-based modelling and assembly function by external CAD tools, and then transferred into the prototype through a conversion module. A hierarchical structure is proposed to partition and organise these imported virtual environment models. Based on this structure, a visibility culling approach is developed for fast rendering and user interaction. The case study has demonstrated the functionality of the proposed prototype system by applying it to a maintenance training application for a refinery bump system, which, in general, has a large number of polygons and a certain depth complexity. Significant speedup in both context rendering and response to user manipulations has been achieved to provide the user with a fast system response within the desktop virtual environment. Compared with the immersive VR system, the proposed system has offered an affordable and portable training media for industrial applications.

Automating Lighting Design for Interactive Entertainment

Recent advances in computer graphics, particularly in real-time rendering, have resulted in major improvements in 3D graphics and rendering techniques in interactive entertainment. In this article we focus on the scene-lighting process, which we define as configuring the number of lights in a scene, their properties (e.g., range and attenuation), positions, angles, and colors. Lighting design is well known among designers, directors, and visual artists for its vital role in influencing viewers' perception by evoking moods, directing their gaze to important areas (i.e., providing visual focus), and conveying visual tension. It is, however, difficult to set positions, angles, or colors for lights within interactive scenes to accommodate these goals because an interactive scene's spatial and dramatic configuration, including mood, dramatic intensity, and the relative importance of different characters, change unpredictably in real-time. There are several techniques developed by the game industry that establish spectacular real-time lighting effects within 3D interactive environments. These techniques are often time- and labor-intensive. In addition, they are not easily used to dynamically mold the visual design to convey communicative, dramatic, and aesthetic functions as addressed in creative disciplines such as art, film, and theatre. In this article we present a new real-time lighting design model based on cinematic and theatric lighting design theory. The proposed model is designed to automatically, and in real-time, adjust lighting in an interactive scene to accommodate the dramatic, aesthetic, and communicative functions described by traditional lighting design theories, while taking artistic constraints on style, visual continuity, and aesthetic function into account.

Modeling the Anatomical Distribution of Sunlight¶‡

One of the major technical challenges in calculating solar irradiance on the human form has been the complexity of the surface geometry (i.e. the surface-normal vis-a-vis the incident radiation). Over 80% of skin cancers occur on the face, head, neck and back of the hands. The quantification, as well as the mapping of the anatomical distribution of solar radiation on the human form, is essential if we are to study the etiology of skin cancers or cataracts or immune system suppression. Using advances in computer graphics, including high-resolution three-dimensional mathematical representations of the human form, the calculation of irradiance has been attained to subcentimeter precision. Lighting detail included partitioning of direct beam and diffuse skylight, shadowing effects and gradations of model surface illumination depending on model surface geometry and incident light angle. With the incorporation of ray-tracing and irradiance algorithms, the results are not only realistic renderings but also accurate representations of the distribution of light on the subject model. The calculation of light illumination at various receptor points across the anatomy provides information about differential radiant exposure as a function of subject posture, orientation relative to the sun and sun elevation. The integration of a geodesic sun-tracking model into the lighting module enabled simulation of specific sun exposure scenarios, with instantaneous irradiance, as well as the cumulative radiant exposure, calculated for a given latitude, date, time of day and duration. Illustration of instantaneous irradiance or cumulative radiant exposure is achieved using a false-color rendering--mapping light intensity to color--creating irradiance or exposure isopleths. This approach may find application in the determination of the reduction in exposure that one achieves by wearing a hat, shirt or sunglasses. More fundamentally, such an analysis tool could provide improved estimates of scenario-specific dose (i.e. absorbed radiant exposure) needed to develop dose-response functions for sunlight-induced disease.

Modeling the Anatomical Distribution of Sunlight¶

ABSTRACTOne of the major technical challenges in calculating solar irradiance on the human form has been the complexity of the surface geometry (i.e. the surface‐normal vis‐a‐vis the incident radiation). Over 80% of skin cancers occur on the face, head, neck and back of the hands. The quantification, as well as the mapping of the anatomical distribution of solar radiation on the human form, is essential if we are to study the etiology of skin cancers or cataracts or immune system suppression. Using advances in computer graphics, including high‐resolution three‐dimensional mathematical representations of the human form, the calculation of irradiance has been attained to subcentimeter precision. Lighting detail included partitioning of direct beam and diffuse skylight, shadowing effects and gradations of model surface illumination depending on model surface geometry and incident light angle. With the incorporation of ray‐tracing and irradiance algorithms, the results are not only realistic renderings but also accurate representations of the distribution of light on the subject model. The calculation of light illumination at various receptor points across the anatomy provides information about differential radiant exposure as a function of subject posture, orientation relative to the sun and sun elevation. The integration of a geodesic sun‐tracking model into the lighting module enabled simulation of specific sun exposure scenarios, with instantaneous irradiance, as well as the cumulative radiant exposure, calculated for a given latitude, date, time of day and duration. Illustration of instantaneous irradiance or cumulative radiant exposure is achieved using a false‐color rendering—mapping light intensity to color—creating irradiance or exposure isopleths. This approach may find application in the determination of the reduction in exposure that one achieves by wearing a hat, shirt or sunglasses. More fundamentally, such an analysis tool could provide improved estimates of scenario‐specific dose (i.e. absorbed radiant exposure) needed to develop dose‐response functions for sunlight‐induced disease.

Focus on Data Acquisition

Focus on Data Acquisition

The GPU enters computing's mainstream

The Siggraph/Eurographics Graphics Hardware 2003 workshop, held in San Diego, will likely be remembered as a turning point in modern computing. In one of those rare moments when a new paradigm visibly begins changing general-purpose computing's course, what has traditionally been a graphics-centric workshop shifted its attention to the nongraphics applications of the graphics processing unit. GPUs, made by Nvidia (www.nvidia.com) and ATI (www.ati.com), function as components in graphics subsystems that power everything from Microsoft's Xbox to high-end visualization systems from Hewlett-Packard and SGI. The GPUs act as coprocessors to CPUs such as Intel's Pentium, using a fast bus such as Intel's Advanced Graphics Port. AGP8x has a peak bandwidth of 2.1 gigabytes per second - speed it needs to avoid inflicting bus starvation on data-hungry GPU coprocessors.

Assembly automation with evolutionary nanorobots and sensor-based control applied to nanomedicine

The author presents a new approach within advanced graphics simulations for the problem of nano-assembly automation and its application for medicine. The problem under study concentrates its main focus on nanorobot control design for assembly manipulation and the use of evolutionary competitive agents as a suitable way to warranty the robustness on the proposed model. Thereby the presented paper summarizes as well distinct aspects of some techniques required to achieve a successful nano-planning system design and its simulation visualization in real time.

Filling the gaps: a research-driven approach to learning computer graphics

This paper describes the design and implementation of a student centered course in advanced undergraduate computer graphics. Instead of providing students with all necessary background before exposing them to recent research, students start with the latest SIGGRAPH proceedings and discover what topics they need to learn to understand them. The power of the group of students is exploited by having each student write a tutorial on one of the topics. Students then trade these written tutorials before being tested on the SIGGRAPH papers themselves. The course aims to nurture lifelong learning skills as well as an understanding of state of the art methods in computer graphics.

Individual differences in exploration using desktop VR

AbstractWith advances in computer graphics, a number of innovative approaches to information visualization have been developed (e.g., Card et al, 1991). Some of these approaches create a mapping between information and corresponding structure in a virtual world. The resulting virtual worlds can be fully three dimensional (3D) or they can be implemented as a series of 2D birds‐eye “snapshots” that are traversed as if they were in 3D, using operations such as panning and zooming interactively (2.5D). This paper reports a study that contrasted 3D and 2.5D performance for people with differing levels of spatial and structure learning ability. Four data collection methods were employed: search task scoring; subjective questionnaires; navigational activity logging and analysis; and administration of tests for spatial and structure‐learning abilities. Analysis of the results revealed statistically significant effects of user abilities, and information environment designs. Overall, this research did not find a performance advantage for using a 3D rather than a 2.5D virtual world. In addition, users in the lowest quartile of spatial ability had significantly lower search performance in the 3D environment. The findings suggest that individual differences in traits such as spatial ability may be important in determining the usability and acceptability of 3D environments.

A Creative Approach To Ship Architecture

In 1980 the author presented a paper to the Institution entitled 'Creative Ship Design' ((1)). The intention in choosing that title was not to imply that ship design as then practised was not capable of being innovative, but rather to make the point that, if naval architects were to fully utilise the benefits becoming available because of the veritable explosion in design methods and creative techniques for dealing with complexity, they then would be enabled to design even more creatively than hitherto. The earlier paper suggested that designers should focus more intensely, at the initial design stages, on ship architecture – both internal and on the topsides – than was possible before the advent of computer aids.Even that long ago rudimentary computerised graphics were becoming available to designers.In the present instance,given a personal belief that current advances in computer graphics makes such possibilities even more achievable, this paper is consequently entitled ”A Creative Approach to Ship Architecture”, with the aim of conveying the architectural emphasis in the approach to ship design being advocated.

The SAGE graphics architecture

The Scalable, Advanced Graphics Environment (SAGE) is a new high-end, multi-chip rendering architecture. Each single SAGE board can render in excess of 80 million fully lit, textured, anti-aliased triangles per second. SAGE brings high quality antialiasing filters to video rate hardware for the first time. To achieve this, the concept of a frame buffer is replaced by a fully double-buffered sample buffer of between 1 and 16 non-uniformly placed samples per final output pixel. The video output raster of samples is subject to convolution by a 5x5 programmable reconstruction and bandpass filter that replaces the traditional RAMDAC . The reconstruction filter processes up to 400 samples per output pixel, and supports any radially symmetric filter, including those with negative lobes (full Mitchell-Netravali filter). Each SAGE board comprises four parallel rendering sub-units, and supports up to two video output channels. Multiple SAGE systems can be tiled together to support even higher fill rates, resolutions, and performance.