Search results for "rendering"
showing 10 items of 138 documents
A simple algorithm for drawing large graphs on small screens
1995
Viewing a large graph in limited display space has traditionally been accomplished using either reduced scale rendering of the graph or by attaching scrollbars to a view window which shows only a small portion of the entire graph. Recent work, however, has concentrated on integrating a locally detailed view with a globally scaled view. We present an algorithm for constructing a view which smoothly integrates local detail and global context in a single view window and describe user interaction with such a display.
Visualization of Large Terrain Using Non-restricted Quadtree Triangulations
2004
This paper presents a set of new techniques oriented towards the real-time visualization of large terrains. These techniques are mainly focused on semi-regular triangulations of non-restricted quadtree terrain representations. Despite the fact that the paper shows that triangulations based on non-restricted quadtrees are as simple and efficient as those based on restricted quadtrees, the new triangulations avoid discontinuity problems among the boundaries of different patches without the need for tree balancing and extra triangles addition. Another important feature of the proposed triangulation is that it incorporates an efficient method for building triangle strips and triangle fans for t…
Spectral adaptation of hyperspectral flight lines using VHR contextual information
2014
Abstract: Due to technological constraints, hyperspectral earth observation imagery are often a mosaic of overlapping flight lines collected in different passes over the area of interest. This causes variations in aqcuisition conditions such that the reflected spectrum can vary significantly between these flight lines. Partly, this problem is solved by atmospherical correction, but residual spectral differences often remain. A probabilistic domain adaptation framework based on graph matching using Hidden Markov Random Fields was recently proposed for transforming hyperspectral data from one image to better correspond to the other. This paper investigates the use of scale and angle invariant…
A Novel Artificial Mosaic Generation Technique Driven by Local Gradient Analysis
2008
Art often provides valuable hints for technological innovations especially in the field of Image Processing and Computer Graphics. In this paper we present a novel method to generate an artificial mosaic starting from a raster input image. This approach, based on Gradient Vector Flow computation and some smart heuristics, permit us to follow the most important edges maintaining at the same time high frequency details. Several examples and comparisons with other recent mosaic generation approaches show the effectiveness of our technique.
Fillets:Cues for connections in Focus+Context views of graph-like diagrams
2003
We apply fillets-smoothing of sharp angles at the joints-between the connections and nodes of graph-like diagrams. In situations where the graph layout is constrained, e.g. Focus+Context views or views where the coordinates of the nodes are informative, fillets can clarify the relationships considerably without altering the layout. A visual search experiment supports our hypothesis that with fillets it is considerably easier to perceive node-connection structures. We discuss algorithms with different tradeoffs for flexibility and performance for rendering these connections in a single pass using OpenGL.
La holografía como recurso didáctico para la enseñanza de contenidos de geometría en primaria
2021
En el presente artículo se analizarán los usos y beneficios que reportaría trabajar con hologramas como material didáctico, como así demuestran los estudios de Ghuloum, Escrivà y Orcos. A través de estas propuestas didácticas se refuerza la idea de que el uso de la técnica de representación en tres dimensiones puede beneficiar al alumnado en la adquisición de los contenidos geométricos presentes en el currículum oficial. El ámbito de la geometría ofrece una amplia gama de contenidos que posibilitan trabajar mediante técnicas de representación gráfica. Cabe destacar, por otra parte, que ahora los estudiantes de educación primaria están socializados en el acceso y uso de imágenes de todo tipo…
Sistemi integrati per la visualizzazione immersiva
2015
Il disegno dell’architettura ha, tra i suoi obiettivi disciplinari, quello di “far vedere” lo spazio, sia nelle sue declinazioni temporali, sia in quelle descrittive di forme, luce, colori e materiali, caratteri connotativi che cerca di riprodurre grazie a metodi di proiezione codificati e tecniche di rappresentazione in continuo mutamento. Tra le tecniche di rappresentazione informatica la visualizzazione immersiva consente di ruotare lo sguardo, in tempo reale, all’interno di uno spazio, cercando di superare i limiti della rappresentazione piana, simulando la visione sferica dello spazio. La tecnica può essere utilizzata sia per vedere la realtà esistente, tramite immagini fotografiche, s…
Warm white LED light by frequency down-conversion of mixed yellow and red Lumogen®
2013
This work reports on the benefits and promising opportunities offered by white LED hybrid technology, based on a mixing perylene-based dyes in order to obtain a warm white light for frequency-down conversion. In a standard Ce:YAG-based white LED, the white light appears cold due to the weakness of red wavelength components in the emission spectrum. In order to obtain a warmer white, one possible solution is to add a red phosphor to the yellow one to move the chromatic coordinates properly, though the luminous efficiency drastically decreases due to the increased light absorption of the coating layer. It is generally believed that the low efficiency of warm white LEDs is the main issue today…
A Constrained Band Selection Method Based on Information Measures for Spectral Image Color Visualization
2011
International audience; We present a new method for the visualization of spectral images, based on a selection of three relevant spectral channels to build a Red-Green-Blue composite. Band selection is achieved by means of information measures at the first, second and third orders. Irrelevant channels are preliminarily removed by means of a center-surround entropy comparison. A visualization-oriented spectrum segmentation based on the use of color matching functions allows for computational ease and adjustment of the natural rendering. Results from the proposed method are presented and objectively compared to four other dimensionality reduction techniques in terms of naturalness and informa…
Translucent medium
2013
8 pages; article in McGraw-Hill Science & Technology Encyclopedia; International audience; A medium allowing light to pass through partially or diffusely. An object cannot be seen clearly through translucent matter. In the most accepted meaning, translucency is used to describe a medium transmitting most of the light but scattering it more or less so that objects seen through it are blurry with soft contours and without details. The closer the object is to the medium the sharper its image through it. There are many examples of such media among natural or manufactured artifacts, including wax paper, milky water, colloidal and hydrogel materials, aerogels, smoke, fog, clouds, optical ceramics…