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Now showing 1 - 5 of 5
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    3D Metamorphosis Between Different Types of Geometric Models
    (Blackwell Publishers Ltd and the Eurographics Association, 2001) Breen, David E.; Mauch, Sean; Whitaker, Ross T.; Mao, Jia
    We present a powerful morphing technique based on level set methods, that can be combined with a variety of scan conversion/model processing techniques. Bringing these techniques together creates a general morphing approach that allows a user to morph a number of geometric model types in a single animation. We have developed techniques for converting several types of geometric models (polygonal meshes, CSG models and MRI scans) into distance volumes, the volumetric representation required by our level set morphing approach. The combination of these two capabilities allows a user to create a morphing sequence regardless of the model type of the source and target objects, freeing him/her to use whatever model type is appropriate for a particular animation.
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    Algorithms for Interactive Editing of Level Set Models
    (The Eurographics Association and Blackwell Publishing Ltd., 2005) Museth, Ken; Breen, David E.; Whitaker, Ross T.; Mauch, Sean; Johnson, David
    Level set models combine a low-level volumetric representation, the mathematics of deformable implicit surfaces and powerful, robust numerical techniques to produce a novel approach to shape design. While these models offer many benefits, their large-scale representation and numerical requirements create significant challenges when developing an interactive system. This paper describes the collection of techniques and algorithms (some new, some pre-existing) needed to overcome these challenges and to create an interactive editing system for this new type of geometric model. We summarize the algorithms for producing level set input models and, more importantly, for localizing/minimizing computation during the editing process. These algorithms include distance calculations, scan conversion, closest point determination, fast marching methods, bounding box creation, fast and incremental mesh extraction, numerical integration and narrow band techniques. Together these algorithms provide the capabilities required for interactive editing of level set models.
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    Interactive Occlusion and Automatic Object Placement for Augmented Reality
    (Blackwell Science Ltd and the Eurographics Association, 1996) Breen, David E.; Whitaker, Ross T.; Rose, Eric; Tuceryan, Mihran
    We present several techniques for producing two visual and modeling effects in augmented reality. The first effect involves interactively calculating the occlusions between real and virtual objects. The second effect utilizes a collision detection algorithm to automatically move dynamic virtual objects until they come in contact with static real objects in augmented reality. All of the techniques utilize calibrated data derived from images of a real-world environment.
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    Object Calibration for Augmented Reality
    (Blackwell Science Ltd and the Eurographics Association, 1995) Whitaker, Ross T.; Crampton, Chris; Breen, David E.; Tuceryan, Mihran; Rose, Eric
    Augmented reality involves the use of models and their associated renderings to supplement information in a real scene. In order for this information to be relevant or meaningful, the models must be positioned and displayed in such a way that they align with their corresponding real objects. For practical reasons this alignment cannot be known a priori, and cannot be hard-wired into a system. Instead a simple, reliable alignment or calibration process is performed so that computer models can be accurately registered with their real-life counterparts. We describe the design and implementation of such a process and we show how it can be used to create convincing interactions between real and virtual objects.
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    Distributed Augmented Reality for Collaborative Design Applications
    (Blackwell Science Ltd and the Eurographics Association, 1995) Ahlers, Klaus H.; Kramer, Andre; Breen, David E.; Chevalier, Pierre-Yves; Crampton, Chris; Rose, Eric; Tuceryan, Mihran; Whitaker, Ross T.; Greer, Douglas
    This paper presents a system for constructing collaborative design applications based on distributed augmented reality. Augmented reality interfaces are a natural method for presenting computer-based design by merging graphics with a view of the real world. Distribution enables users at remote sites to collaborate on design tasks. The users interactively control their local view, try out design options, and communicate design proposals. They share virtual graphical objects that substitute for real objects which are not yet physically created or are not yet placed into the real design environment.We describe the underlying augmented reality system and in particular how it has been extended in order to support multi-user collaboration. The construction of distributed augmented reality applications is made easier by a separation of interface, interaction and distribution issues. An interior design application is used as an example to demonstrate the advantages of our approach.