Lilian Aveneau

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A6sftcret This paper presents a 3D simulation software of radio waves propagation for the mobile systems in outdoor and indoor environments. The software allows to predict the coverage zone of a base station and the behaviour of the transmission channel. After a brief recall of the radio channel Characteristics for narrow and wide band signals, the(More)
Fast ray-tracing requires an efficient acceleration structure. For architectural environment, the most famous is the cells-and-portals one. Many previous works attempt to automatically construct a good cells-and-portals. We propose a new acceleration structure which extends the classical cells-and-portals. It is automatically extracted from the topological(More)
Rendering high quality soft shadows from area light sources is necessary to increase the level of realism. Quality soft shadows are closely related to the visibility computation. An accurate visibility information improves the shadows realism. However, this remains a challenging problem since even small visibility approximations can lead to unacceptable(More)
We present a set of new techniques to compute an exact polygon-to-polygon visibility in Plücker space. The contributions are based on the definition of the minimal representation of lines stabbing two convex polygons. The new algorithms are designed to indicate useless computations, which results in more compact visibility data, faster to exploit, and in a(More)
Many rendering systems rely on spherical harmonics or wavelets that provide a mean to solve the rendering equation using scalar products. In addition, these basis of functions may represent hemispherical lighting, visibility and reflectance with a small number of coefficients. However, their use requires the projection of each term of the rendering(More)
This report presents a novel approach to compute high quality and alias-free soft shadows using exact visibility computations. This work relies on a theoritical framework allowing to group lines according to the geometry they intersect. From this study, we derive a new algorithm encoding lazily the visibility from a polygon. Contrary to previous works on(More)
Nowadays, the need for wireless communication systems is increasing in transport domain. These systems have to be operational in every type of environment and particularly tunnels for metro applications. These ones can have rectangular, circular or arch-shaped cross section. Furthermore, they can be straight or curved. This article presents a new method to(More)
The purpose of this paper is to describe the results of a CDMA digital transmission simulation in terms of quality, based on deterministic modeling of the propagation channel. This modeling allows a fast computation of the channel Power Delay Profile (PDP), which is the common input of a digital transmission system. Thus, the harmful impact of the channel(More)
This chapter introduces global visibility computation using Grassmann Algebra. Visibility computation is a fundamental task in computer graphics, as in many other scientific domains. While it is well understood in two dimensions, this does not remain true in higher dimensional spaces. Grassmann Algebra allows to think about visibility at a high level of(More)