In this paper, we are investigating the performance of several IDW implementations on different SIMD architectures (Single Instruction Multiple Data). The SIMD architectures addressed in this paper are considered cost effective and readily available on the desktop as compared to super-computers such as the IBM Roadrunner or the Cray XT5. Two main classes of SIMD architectures can be identified from the range of products available now: (a) the architectures that are integrated in the CPU itself, such as SSE or AltiVec; and (b) the architectures located on a dedicated board such as the GPGPUs from Nvidia or ATI. This paper evaluates one SIMD architecture selected from each group. The evaluation is based on the performance measured on each architecture over various datatypes and different problem sizes.

The Living Canvas initiative aims to use a performer on stage as a dynamic projection surface. Using machine vision in the near-infrared spectrum enables the system to follow and adapt to the performer, restricting projection to the silhouette. Ultimately, the system aims to create the illusion of a completely dynamic costume. This paper introduces the concept and presents an implementation and analysis of the performance-critical stages of the projection pipeline, proving the feasibility of the idea as well as analysing the limitations introduced by current digital projection technology.

We present a novel low-cost method for visual communication and telepresence in a CAVE -like environment, relying on 2D stereo-based video avatars. The system combines a selection of proven efficient algorithms and approximations in a unique way, resulting in a convincing stereoscopic real-time representation of a remote user acquired in a spatially immersive display. The system was designed to extend existing projection systems with acquisition capabilities requiring minimal hardware modifications and cost. The system uses infrared-based image segmentation to enable concurrent acquisition and projection in an immersive environment without a static background. The system consists of two color cameras and two additional b/w cameras used for segmentation in the near-IR spectrum. There is no need for special optics as the mask and color image are merged using image-warping based on a depth estimation. The resulting stereo image stream is compressed, streamed across a network, and displayed as a frame-sequential stereo texture on a billboard in the remote virtual environment.

We introduce a method to imperceptibly embed arbitrary binary patterns into ordinary color images displayed by unmodified off-the-shelf digital light processing (DLP) projectors. The encoded images are visible only to cameras synchronized with the projectors and exposed for a short interval, while the original images appear only minimally degraded to the human eye. To achieve this goal, we analyze and exploit the micro-mirror modulation pattern used by the projection technology to generate intensity levels for each pixel and color channel. Our real-time embedding process maps the user's original color image values to the nearest values whose camera-perceived intensities are the ones desired by the binary image to be embedded. The color differences caused by this mapping process are compensated by error-diffusion dithering. The non-intrusive nature of our approach allows simultaneous (immersive) display and acquisition under controlled lighting conditions, as defined on a pixel level by the binary patterns. We therefore introduce structured light techniques into human-inhabited mixed and augmented reality environments, where they previously often were too intrusive.

We present a distributed scene graph architecture for use in the blue-c, a novel collaborative immersive virtual environment. We extend the widely used OpenGL Performer toolkit to provide a distributed scene graph maintaining full synchronization down to vertex and texel level. We propose a synchronization scheme including customizable, relaxed locking mechanisms. We demonstrate the functionality of our toolkit with two prototype applications in our high-performance virtual reality and visual simulation environment.

We present blue-c , a new immersive projection and 3D video acquisition environment for virtual design and collaboration. It combines simultaneous acquisition of multiple live video streams with advanced 3D projection technology in a CAVE™-like environment, creating the impression of total immersion. The blue-c portal currently consists of three rectangular projection screens that are built from glass panels containing liquid crystal layers. These screens can be switched from a whitish opaque state (for projection) to a transparent state (for acquisition), which allows the video cameras to "look through" the walls. Our projection technology is based on active stereo using two LCD projectors per screen. The projectors are synchronously shuttered along with the screens, the stereo glasses, active illumination devices, and the acquisition hardware. From multiple video streams, we compute a 3D video representation of the user in real time. The resulting video inlays are integrated into a networked virtual environment. Our design is highly scalable, enabling blue-c to connect to portals with less sophisticated hardware.

We present a spatialized audio rendering system for the use in immersive virtual environments. The system is optimized for rendering a sufficient number of dynamically moving sound sources in multi-speaker environments using off-the-shelf audio hardware. Based on simplified physics-based models, we achieve a good trade-off between audio quality, spatial precision, and performance. Convincing acoustic room simulation is accomplished by integrating standard hardware reverberation devices as used in the professional audio and broadcast community. We elaborate on important design principles for audio rendering as well as on practical implementation issues. Moreover, we describe the integration of the audio rendering pipeline into a scene graph-based virtual reality toolkit.

We present JAPE, a flexible prototyping system to support the design of a new advanced collaborative virtual environment. We describe the utilization of different hard- and software components to quickly build a flexible, yet powerful test bed for application and algorithm development. These components include a 3-D rendering toolkit, live video acquisition, speech transmission, and the control of tracking and interaction devices. To facilitate the simultaneous design of applications and algorithms that take advantage of unique features of new collaborative virtual environments, we provide the developer with a flexible prototyping toolkit which emulates the functionality of the final system. The applicability of JAPE is demonstrated with several prototype applications and algorithms.

The goal of the Swiss-Tx project is to develop, build and install the first Swiss tera-flop supercomputer called Swiss-T2, which is mainly based on commodity parts.Only the communication hardware and communication software is custom-made, because available off-theshelf products, such as Ethernet with the socket interface, do not offer the necessary bandwidth, latency, and functionality.In this paper, we present a new efficient communication architecture for commodity supercomputing called Fast Communication Interface (FCI), and we introduce T-NET, the custom-made high-performance communication hardware for the Swiss-Tx supercomputers.The highlights are low-latency, highbandwidth, and portability.Portability means that the communication hardware and software is mainly platform independent and that a large number of modern workstations and standard operating systems can be used as they are.A full implementation of the standardized MPI (Message Passing Interface), written entirely on top of FCI, is also available.