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Now showing 1 - 5 of 5
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    Feature Identification and Extraction in Function Fields
    (The Eurographics Association, 2007) Anderson, John C.; Gosink, Luke J.; Duchaineau, Mark A.; Joy, Kenneth I.; K. Museth and T. Moeller and A. Ynnerman
    We present interactive techniques for identifying and extracting features in function fields. Function fields map points in n-dimensional Euclidean space to 1-dimensional scalar functions. Visual feature identification is ac- complished by interactively rendering scalar distance fields, constructed by applying a function-space distance metric over the function field. Combining visual exploration with feature extraction queries, formulated as a set of function-space constraints, facilitates quantitative analysis and annotation. Numerous application domains give rise to function fields. We present results for two-dimensional hyperspectral images, and a simulated time-varying, three-dimensional air quality dataset.
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    Marker-less Real-time Camera Registration for Mixed Reality
    (The Eurographics Association, 2007) Liverani, Alfredo; Grandi, Stefania; Raffaele De Amicis and Giuseppe Conti
    A real-time and robust algorithm for 3D camera registration in a Mixed Reality (MR) environment is described in this paper. The most used technique for camera pose (position and orientation with respect to a fixed or moving object) is based on fiducial marker tracking. This method guarantees good results in real-time with a single camera, but needs several high contrast printed markers on external world in order to make possible the calculation of camera parameters and positioning. Thus real 3D geometric data are grabbed only through already known markers. The aim of this research is a real-time monocular camera tracking and registration through automatic image features extraction from video streaming. The first implementation of the method, several examples and confrontation with non interactive algorithm for SFM (Structure From Motion) have demonstrated that this meets the real-time response and sufficient precision needed by a Mixed Reality environment.
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    A Quantitative Assessment of the Impact on Spatial Understanding of Exploring a Complex Immersive Virtual Environment using Augmented Real Walking versus Flying
    (The Eurographics Association, 2007) Interrante, Victoria; O'Rourke, Eleanor; Gray, Leanne; Anderson, Lee; Ries, Brian; Bernd Froehlich and Roland Blach and Robert van Liere
    When an immersive virtual environment spans an area that is larger than the available physical space for real walking, one may use an augmented walking method such as Seven League Boots to enable participants to explore the space while gaining proprioceptive feedback that is similar to what they would experience with normal walking. In this paper, we present the results of a preliminary experiment in which we seek to quantitatively assess the extent to which participants are able to make more accurate spatial judgments about the locations of previously-seen targets in a complicated virtual city environment, experienced using a head-mounted display, after traveling to them using augmented real walking ( boots ) versus virtual walking enabled by a button press on a hand-held wand. In a series of trials, we ask participants to follow paths of increasing complexity from a home base to different hidden targets in the environment and back. At each endpoint, with the path markings turned off, we ask participants to point, through the intervening alleyway walls, to the location they believe they started from. Participants are able to make real turns with their bodies in both locomotion conditions, however they are able to make real forward movement only under the augmented walking condition. Each participant completes eight trials under each locomotion condition, with the target locations and the order of experiencing each method counterbalanced between participants. In data collected from six participants so far, we are finding that the median angle error is significantly greater, overall, in the wand locomotion condition than in the boots locomotion condition, and that the errors tend to increase, overall, as the path complexity increases (from two segments to four segments) in the wand locomotion condition but not in the boots locomotion condition.
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    Visualization Notations, Models and Taxonomies
    (The Eurographics Association, 2007) Brodlie, Ken; Noor, Nurul Mohd; Ik Soo Lim and David Duce
    Visualization taxonomies are an important means of imposing some structure on a rather diverse field. We review some earlier work in this area, particularly work based on the use of a notation to label classes of visualization techniques that are appropriate to particular entities. We propose a new notation introducing it in the context of a new visualization reference model, one we hope will lead eventually to a means of describing visualizations in a clear and unambiguous way.
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    Methods for Spatial Data Quality of 3D City Models
    (The Eurographics Association, 2007) Krämer, Michel; Haist, Jörg; Reitz, Thorsten; Raffaele De Amicis and Giuseppe Conti
    3D city models are nowadays used in very different applications. Due to this, the commercial exchange and, thus, the demand for high quality data becomes more and more important. We describe a quality model that defines common parameters used for spatial quality measurement, especially when dealing with 3D city models. Therefore, we explore different representations of city models: the reality, the user's idea and the digital data set. A welldefined mathematical formalism which addresses the different quality parameters is presented. This formalism also helps to create algorithms for measurement and improvement of spatial data quality. The aim is to be able to define uniformed criteria which can be easily transformed into software. The implemented prototype serves as base for the evaluation in which we provide examples based on actual data sets using typical quality requirements.