133,583 research outputs found

    Non-photorealistic volume rendering using stippling techniques

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    Journal ArticleSimulating hand-drawn illustration techniques can succinctly express information in a manner that is communicative and informative. We present a framework for an interactive direct volume illustration system that simulates traditional stipple drawing. By combining the principles of artistic and scientific illustration, we explore several feature enhancement techniques to create effective, interactive visualizations of scientific and medical datasets. We also introduce a rendering mechanism that generates appropriate point lists at all resolutions during an automatic preprocess, and modifies rendering styles through different combinations of these feature enhancements. The new system is an effective way to interactively preview large, complex volume datasets in a concise, meaningful, and illustrative manner. Volume stippling is effective for many applications and provides a quick and efficient method to investigate volume models

    Illustrative interactive stipple rendering

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    Journal ArticleAbstract-Simulating hand-drawn illustration can succinctly express information in a manner that is communicative and informative. We present a framework for an interactive direct stipple rendering of volume and surface-based objects. By combining the principles of artistic and scientific illustration, we explore several feature enhancement techniques to create effective, interactive visualizations of scientific and medical data sets. We also introduce a rendering mechanism that generates appropriate point lists at all resolutions during an automatic preprocess and modifies rendering styles through different combinations of these feature enhancements. The new system is an effective way to interactively preview large, complex volume and surface data sets in a concise, meaningful, and illustrative manner. Stippling is effective for many applications and provides a quick and efficient method to investigate both volume and surface models

    Visualization based on interactive clipping: application to confocal data

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    We have explored how clipping can be exploited in an interactive manner to visualize massive three-dimensional datasets. In essence, the proposed interactive clipping approach involves the dynamic adjustment of the clipping plane to expose any cross-section of the volume data and subsequent adjustment of the clipped surface to the best view position using a combination of rotation and translation. The thesis describes the design, implementation and application of our interactive-clipping-based visualization system. The implementation is done with OpenGL and C++, thus resulting in a highly portable and flexible system. For illustration, two types of scientific datasets, confocal data of a plant stem and calculated electronic charge density distributions are successfully visualized. The data are displayed using pixel- and texture-based rendering; the latter is shown to give a better performance

    Animating Human Muscle Structure

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    Graphical simulations of human muscle motion and deformation are of great interest to medical education. In this article, the authors present a technique for simulating muscle deformations by combining physically and geometrically based computations to reduce computation cost and produce fast, accurate simulations

    A Framework for Datatype Transformation

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    We study one dimension in program evolution, namely the evolution of the datatype declarations in a program. To this end, a suite of basic transformation operators is designed. We cover structure-preserving refactorings, but also structure-extending and -reducing adaptations. Both the object programs that are subject to datatype transformations, and the meta programs that encode datatype transformations are functional programs.Comment: Minor revision; now accepted at LDTA 200

    Using a categorisation structure to understand interaction in children’s books

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    Children’s books can vary greatly in the type of and depth of interaction that is required from the reader. The types of interaction demanded by different types of books can be explored using contrasting paradigms. Previously Timpany & Vanderschantz (2012) proposed a categorisation of interactive children’s books that used two continuums that took into consideration Physical Enhancement and Content Sequencing. This paper looks at those categorisations made by Timpany & Vanderschantz (2012) and considers how the multitude of formats addresses either the physical or intellectual aspects of children’s reading and how this then may be used to engage the reader. To do this, a database of 132 books was audited to assess the interactivity of these books against those categorisation systems. The range of books surveyed is discussed in terms of what methods are used to create the interaction within each of the interactivity levels and across types of books. Findings from this audit demonstrate interesting interactions between age, physical enhancement versus content sequencing, and the relationship of these to mechanisms for interactivity such as paper engineering, illustration and story structure. The majority of the books in the sample have no interactive qualities on one of the two-categorisation scales. Physically enhanced books were marginally more highly represented on the scale at higher levels of interactivity. Counter intuitively, the physically interactive pop up books were seen to fall predominantly in lower categories (1 or 2) for physical enhancement, while books requiring image search, an intellectual activity, were also predominantly in the lower categories (1 or 2) for content sequencing

    Interactive (statistical) visualisation and exploration of a billion objects with Vaex

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    With new catalogues arriving such as the Gaia DR1, containing more than a billion objects, new methods of handling and visualizing these data volumes are needed. In visualization, one problem is that the number of datapoints can become so large, that a scatter plot becomes cluttered. Another problem is that with over a billion objects, only a few cpu cycles are available per object if one wants to process them within a second, making traditional methods by rendering glyphs not viable. Instead, we show that by calculating statistics on a regular (N-dimensional) grid, visualizations of a billion objects can be done within a second on a modern desktop computer. This is achieved using memory mapping of hdf5 files together with a simple binning algorithm, which are part of a Python library called vaex. This enables efficient exploration or large datasets interactively, making science exploration of large catalogues feasible. Vaex is a Python library, which also integrates well in the Jupyter/Numpy/Astropy/matplotlib stack. Build on top of this is the vaex application, which allows for interactive exploration and visualization. The motivation for developing vaex is the catalogue of the Gaia satellite, however, vaex can also be used on SPH or N-body simulations, any other (future) catalogues such as SDSS, Pan-STARRS, LSST, WISE, 2MASS, etc. or other tabular data. The homepage for vaex is http://vaex.astro.rug.nl.Comment: 6 pages, 4 figures, conference proceeding for the IAU symposium 325 on Astroinformatics (accepted), webpage http://vaex.astro.rug.n
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