41367426
Incorporating Geometric Registration With Pc-Cluster Rendering For Flexible Tiled Displays
We describe a display system that automatically registers an array of casually positioned projectors and drives the display with a PC cluster. The display system uses a camera to compute the necessary transformations to geometrically align multiple overlapping projectors. Geometric alignment is realized through real-time corrective warping applied in the rendering pipeline. This combination of camera-aided display alignment with the PC-cluster rendering engine provides a display system that is easy to configure and reconfigure, accommodates casually tiled projectors and arbitrary display surfaces, and can be operational in a very short period of time.
37436531
A practical and flexible tiled display system
Computer graphics and high-resolution digital imagery are becoming increasingly pervasive in communities not traditionally associated with graphics. Commodity graphics cards and digital cameras, along with powerful modeling software, allow organizations such as libraries, museums, and small businesses to produce expressive and realistic computer generated imagery, far surpassing the capabilities of current desktop monitors. What remains elusive to these groups is access to affordable and easy to use large format display technology. We present a practical system for deploying flexible projector based tiled displays. Our framework integrates two key components: (1) self-calibrating display geometry with real-time geometric correction and (2) PC-based distributed rendering that supports an established graphics API. Our system's display geometry is easy to configure and reconfigure, accommodates casually tiled projectors and arbitrary display surfaces, and can be operational in a matter of minutes. In addition, the underlying distributed rendering architecture (WireGL) is transparent to existing OpenGL applications, requiring no custom APIs or re-compilation of existing OpenGL executables. In short, we present a practical and flexible low-cost tiled display system that is simple to deploy and easy to operate.
7129849
Geometrically correct imagery for teleconferencing
Current camera-monitor teleconferencing applications produce unrealistic imagery and break any sense of presence for the participants. Other capture/display technologies can be used to provide more compelling teleconferencing. However, complex geometries in capture/display systems make producing geometrically correct imagery difficult. It is usually impractical to detect, model and compensate for all effects introduced by the capture/display system. Most applications simply ignore these issues and rely on the user acceptance of the camera-monitor paradigm.
This paper presents a new and simple technique for producing geometrically correct imagery for teleconferencing environments. The necessary image transformations are derived by finding a mapping between a capture and display device for a fixed viewer location. The capture/display relationship is computed directly in device coordinates and completely avoids the need for any intermediate, complex representations of screen geometry, capture and display distortions, and viewer location. We describe our approach and demonstrate it via several prototype implementations that operate in real-time and provide a substantially more compelling sense of presence than the standard teleconferencing paradigm.
10099377
Geometric and photometric restoration of distorted documents
We present a system to restore the 2D content printed on distorted documents. Our system works by acquiring a 3D scan of the document's surface together with a high-resolution image. Using the 3D surface information and the 2D image, we can ameliorate unwanted surface distortion and effects from non-uniform illumination. Our system can process arbitrary geometric distortions, not requiring any pre-assumed parametric models for the document's geometry. The illumination correction uses the 3D shape to distinguish content edges from illumination edges to recover the 2D content's reflectance image while making no assumptions about light sources and their positions. Results are shown for real objects, demonstrating a complete framework capable of restoring geometric and photometric artifacts on distorted documents
17720018
Conformal deskewing of non-planar documents
This paper presents an approach that uses conformal mapping to parameterize a document's 3D shape to a 2D plane. Using this conformal parametrization, a restorative mapping between an image of the distorted document and a "flattened" representation of the document can be computed and used to deskew the image. Our experiments show that arbitrarily distorted documents can be restored to within a single pixel of their true planar format. In addition, surface points can be constrained to map to specified locations in the restored 2D plane.
1120694
Image restoration of arbitrarily warped documents
We present a framework for acquiring and restoring images of warped documents. The purpose of our restoration is to create a planar representation of a once planar document that has undergone an arbitrary and unknown rigid deformation. To accomplish this restoration, our framework acquires and flattens the 3D shape of a warped document to determine a nonlinear image transform that can correct for image distortion caused by the document's shape. Our framework is designed for use in library and museum digitization efforts where very old and badly damaged manuscripts are imaged.
12045621
Visualization of the Interaction of Multiple Sclerosis Lesions with Adjacent White Matter Fibers Using Streamtubes and Streamsurfaces
Multiple sclerosis (MS) is a chronic disease of the central nervous system that predominantly affects young adults during their most productive years. Pathologically, MS is characterized by the presence of areas of demyelination and T-cell predominant perivascular inflammation in the brain white matter. In order to study the effect of MS lesion on the white matter, we acquire diffusion tensor imaging (DTI) data on MS patients and employ streamtubes and streamsurfaces to visualize the DTI data. We also register structural data sets with DTI data sets and generate isosurfaces of the MS lesions and the ventricles. The simultaneous visualization of all the models has the potential to elucidate the complex relationship between the MS lesions, the white matter neural fibers and the affected gray matter regions.
12462654
3D Model Acquisition by Tracking 2D Wireframes
This paper presents a semi-automatic wireframe acquisition system. The system uses real-time (25Hz) tracking of a user specified 2D wireframe and intermittent camera pose parameters to accumulate 3D position information. The 2D tracking framework enables the application of model-based constraints in an intuitive way which interacts naturally with the Kalman filter formulation used. In particular, this is used to introduce feedback from the current 3D shape estimate to improve the robustness of the 2D tracking. The scheme allows wireframe models of simple edge based objects to be built in around 5 minutes.
15396026
The literate-programming paradigm
Literate programming, a technique for coding software systems that promotes readability and comprehension, is examined in detail. The current literate-programming paradigm is reviewed by looking at two sample literate programs. A critique of literate programming as it is currently used is presented, and methods for enhancing the process are explored. A number of new facilities are proposed, and restrictions on current literate-programming practices are suggested.<<ETX>>
9641916
Investigating the Relationship between Internet Privacy Concerns and Online Purchase Behavior
Many organizations now emphasize the use of technology that can help them get closer to consumers and build ongoing relationships with them. The ability to compile consumer data profiles has been made even easier with Internet technology. However, it is often assumed that consumers like to believe they can trust a company with their personal details. Lack of trust may cause consumers to have privacy concerns. Addressing such privacy concerns may therefore be crucial to creating stable and ultimately profitable customer relationships. Three specific privacy concerns that have been frequently identified as being of importance to consumers include unauthorized secondary use of data, invasion of privacy, and errors. Results of a survey study indicate that both errors and invasion of privacy have a significant inverse relationship with online purchase behavior. Unauthorized use of secondary data appears to have little impact. Managerial implications include the careful selection of communication channels for maximum impact, the maintenance of discrete “permission-based” contact with consumers, and accurate recording and handling of data.
37211415
A Hypertext for Literate Programming
In this paper we describe a hypertext presentation for the WEB system for literate programming. The requirements for an environment for modern literate programming are analyzed and the WEB hypertext system is proposed. Different types of windows for displaying text, indices and graphical representations are discussed. All semantic links and operators using them are analyzed. The proposed architecture of the WEB hypertext system includes a general purpose relational database management system. Mapping between hypertext queries and relational database queries is provided. The system allows the user to define new hypertext operations by providing the corresponding SQL queries for the underlying relational database. The described system can be easily extended by many other types of queries and applications.