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Now showing 1 - 5 of 5
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    Surfel Octrees: A New Scheme for Interactive Inspection of Anatomy Atlases in Client-Server Applications
    (The Eurographics Association, 2015) Surinyac, Jordi; Brunet, Pere; Mateu Sbert and Jorge Lopez-Moreno
    Nowadays, an increasing interest on tele-medicine and tele-diagnostic solutions can be observed, with client/server architectures for remote inspection of volume image-based medical data which are becoming more and more popular. The use of portable devices is gradually spreading due to their portability and easy maintenance. In this paper, we present an efficient data model for segmented volume models based on a hierarchical data structure of surfels per anatomical structure. Surfel Octrees are compact enough for transmission through networks with limited bandwidth, and provide good visual quality in the client devices at a limited footprint. Anatomy atlases are represented as octree forests, supporting local interaction in the client device and selection of groups of medical organs. After presenting the octree generation and interaction algorithms, we present several examples and discuss the interest of the proposed approach in low-end devices such as mobiles and tablets.
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    A New Approach for Perceptually-based Fitting Strokes into Straight Segments
    (The Eurographics Association, 2015) Plumed, Raquel; Company, Pedro; Varley, Peter A. C.; Mateu Sbert and Jorge Lopez-Moreno
    Fitting the strokes of a sketch into geometrical primitives is still an open problem, even for sketches which depict bare line-drawings without annotations. Such sketches comprise only discrete strokes, sequences of points obtained between a pen down and a pen up. It is commonly accepted that the best perceptual fittings depend on the context. Hence, we will only be able to extract the best line-drawing from a sketch by considering a complex recognition flow, where lines must be iteratively fitted according to different tentative relationships until the most plausible line-drawing is reached. The recognition task considered in this paper is determining whether a stroke represents a straight line. The goal is doing it in a way that allows for iterative recognition flows. The novel contributions are that our approach is more fast and robust than accurate, uses perceptual criteria to classify strokes, and returns likeliness instead of a simple yes/no.
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    Mobile Multiview Diffuse Texture Extraction
    (The Eurographics Association, 2015) Kán, Peter; Kaufmann, Hannes; Andrea Giachetti and Silvia Biasotti and Marco Tarini
    This paper presents a novel method for diffuse texture extraction from a set of multiview images. We address the problem of specularities removal by pixel value minimization across multiple automatically aligned input images. Our method is based on the fact that the presence of specular reflection only increases the captured pixel value. Moreover, we propose an algorithm for estimation of material region in the image by optimization on the GPU. Previous methods for diffuse component separation from multiple images require a complex hardware setup. In contrast to that, our method is highly usable because only a mobile phone is needed to reconstruct diffuse texture in an environment with arbitrary lighting. Moreover, our method is fully automatic and besides capturing of images from multiple viewpoints it does not require any user intervention. Many fields can benefit from our method, particularly material reconstruction, image processing, and digital content creation.
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    Explaining Neighborhood Preservation for Multidimensional Projections
    (The Eurographics Association, 2015) Martins, Rafael Messias; Minghim, Rosane; Telea, Alexandru C.; Rita Borgo and Cagatay Turkay
    Dimensionality reduction techniques are the tools of choice for exploring high-dimensional datasets by means of low-dimensional projections. However, even state-of-the-art projection methods fail, up to various degrees, in perfectly preserving the structure of the data, expressed in terms of inter-point distances and point neighborhoods. To support better interpretation of a projection, we propose several metrics for quantifying errors related to neighborhood preservation. Next, we propose a number of visualizations that allow users to explore and explain the quality of neighborhood preservation at different scales, captured by the aforementioned error metrics.We demonstrate our exploratory views on three real-world datasets and two state-of-the-art multidimensional projection techniques.
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    Tiled Projection Onto Deforming Screens
    (The Eurographics Association, 2015) Kim, Hyosun; Schinko, Christoph; Havemann, Sven; Redi, Ivan; Redi, Andrea; Fellner, Dieter W.; Rita Borgo and Cagatay Turkay
    For the next generation of visual installations it will not be sufficient to surround the visitor by stunning responsive audiovisual experiences - the next step is that space itself deforms in response to the user or user groups. Dynamic reconfigurable spaces are a new exciting possibility to influence the behaviour of groups and individuals; they may have the potential of stimulating various different social interactions and behaviours in a user-adapted fashion. However, some technical hurdles must be overcome. Projecting on larger surfaces, like a ceiling screen of 6 8 meters, is typically possible only with a tiled projection, i.e., with multiple projectors creating one large seamless image. This works well with a static ceiling; however, when the ceiling dynamically moves and deforms, the tiling becomes visible since the images no longer match. In this paper we present a method that can avoid such artifacts by dynamically adjusting the tiled projection to the deforming surface. Our method is surprisingly simple and efficient, and it does not require any image processing at runtime, nor any 3D reconstruction of the surface at any point.