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Now showing 1 - 5 of 5
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    Interactive Grid Based Binning for Information Visualization
    (The Eurographics Association, 2008) Longshaw, S. M.; Turner, M. J.; Hewitt, W. T.; Ik Soo Lim and Wen Tang
    Clutter within information visualization (infovis) systems is an area of continuing concern and is receiving increasing research interest. Solutions to the problem vary in their approach, ranging from novel visualizations designed specifically to cope with high data density, through to statistical methodologies such as binning. This paper presents a flexible method that allows interactive placement of a grid based binning system that aims to enhance traditional information visualization techniques. User evaluations employing two specific visualization methods are described using a prototype grid based binning system. The method is shown to be a quick and easy way to visually segment a data domain, while the two visualization techniques presented are shown to provide effective data overview. Due to the abstracted nature of the binning grid, its applicability goes beyond the examples provided in this paper, therefore it could be considered as a generic data reduction and/or overview technique within many systems.
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    HyperStreamball Visualization for Symmetric Second Order Tensor Fields
    (The Eurographics Association, 2006) Liu, J.; Turner, M.; Hewitt, W. T.; Perrin, J. S.; Louise M. Lever and Mary McDerby
    This paper proposes a new 3D tensor glyph called a hyperstreamball that extends streamball visualization used within fluid flow fields to applications within second order tensor fields. The hyperstreamball is a hybrid of the ellipsoid, hyperstreamline and hyperstreamsurface. With the proposed system a user can easily interactively change the visualization. First, we define the distance of the influence function which contributes a potential field that can be designed to highlight the three eigenvectors and eigenvalues of a real symmetric tensor at any sample point. Second, we discuss the choice of source position and how the user can control the parameter mapping between the field data and the implicit function. Finally, we test our results using both synthetic and real data that shows the hyperstreamball's two main advantages: one is that hyperstreamballs blend and split with each other automatically depending on the tensor data, and the other advantage is that the user can achieve both discrete and continuous representation of the data based on a single geometrical description.
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    A Physical Model for the Polarized Scattering of Light
    (The Eurographics Association, 2008) Brayford, David; Turner, Martin; Hewitt, W. T.; Ik Soo Lim and Wen Tang
    The change in polarization state due to the interaction of light with the surface and beneath the surface of an object has become increasingly important in realistic image synthesis of materials such as metallic, iridescent and pearlescent paint, skin, hair and cosmetics. This paper presents a model for the anisotropic scattering of polarized light based upon the physics of light; which is capable of calculating both partial and complete polarization using a combination of Jones and Mueller calculus, as well as incorporating self shadowing effects.
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    A Lemon is not a Monstar: Visualization of Singularities of Symmetric Second Rank Tensor Fields in the Plane
    (The Eurographics Association, 2008) Liu, J.; Hewitt, W. T.; Lionheart, W. R. B.; Montaldi, J.; Turner, M.; Ik Soo Lim and Wen Tang
    In the visualization of the topology of second rank symmetric tensor fields in the plane one can extract some key points (degenerate points), and curves (separatrices) that characterize the qualitative behaviour of the whole tensor field. This can provide a global structure of the whole tensor field, and effectively reduce the complexity of the original data. To construct this global structure it is important to classify those degenerate points accurately. However, in existing visualization techniques, a degenerate point is only classified into two types: trisector and wedge types. In this work, we will apply the theory from the analysis of binary differential equations and demonstrate that, topologically, a simple degenerate point should be classified into three types: star (trisector), lemon and monstar. The later two types were mistakenly regarded as a single type in the existing visualization techniques.
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    Perlin Noise and 2D Second-Order Tensor Field Visualization
    (The Eurographics Association, 2005) Liu, J.; Perrin, J.; Turner, M.; Hewitt, W. T.; Louise M. Lever and Mary McDerby
    There has been much research in the use of texture for visulization the vector field data, whereas there has only been a few papers concerned specifically with tensor field data. This set is more complex and embeds more information than vector fields. In this paper, firstly texture is modeled by Perlin Noise. We show that by controlling the parameters of Perlin Noise, the user can control the output texture effectively, which is similar to Spot Noise. Then the modeled texture is used to visualize eigenvector fields of tensor fields by simple convolution. Several examples are shown. Compared to Line Integration Convolution, this method does not need to integrate the streamline along the vector field.