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Trazado de haces de rayos en escenas estructuradas espacialmente mediante árboles octales.

P. González López1
F. Gisbert Cantó2

1 Dpto. Informática, E.U.P.A., Univ. Castilla-La Mancha, 02071 Albacete, España
2 Dpto. LSI e IS, Fac. Informática , Univ. Politécnica Madrid, 28071 Madrid, España

Abstract

In this work we present a new proposal to obtain photo-realistic images. This alternative for ray tracing optimization is based on combined use of the ideas contributed by different alternatives of acceleration. Firstly we use structures that allow us to guide any ray inside the scene (octrees), facilitating that a ray only has to calculate its intersection with a reduced number of objects (those located on the node to which the ray arrived). On the other hand, in these structures, we trace a group of rays contained in a beam (beam tracing). We offer, therefore, an alternative of acceleration that improves the benefits, regarding other previous proposals, as the resolution and the quality of the image is being increased.

To demonstrate the power of the algorithm that we propose, we will process several scenes and compare the results with those obtained by other alternative of acceleration. Firstly we will compare it with other algorithms that consider the ray individually and trace it in scenes structured by means of octrees. We have also selected an algorithm that proposes another strategy of decomposition of the scene, in this case it uses a bounding volume hierarchy. Their use will allow us to see the excellent behavior of our algorithm in those scenes in which the algorithms based on bounding volumes obtain better results than those based on octrees.

Sumario

En este trabajo se presenta una nueva propuesta de optimización de la generación de imágenes de alta calidad (foto-realistas) basada en el trazado de rayos. En ella, se utilizan de modo conjunto las ideas aportadas por diferentes alternativas de aceleración. En primer lugar, se utilizan estructuras que permiten guiar a un rayo dentro de la escena (árboles octales), facilitando que cada rayo solo calcule su intersección con un número reducido de objetos (aquellos situados en los nodos que se encuentre en su camino). Por otra parte, en estas estructuras, se realiza el trazado de los rayos agrupados en haces. Se aporta , por tanto, una alternativa de aceleración que mejora los resultados obtenidos, respecto a otras propuestas previas, conforme se incrementan la resolución y la calidad de la imagen a generar.

Keywords: Ray Tracing Acceleration, Coherence, Octree.



 

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