Frederic Pérez

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Rendering participating media is important for a number of domains, ranging from commercial applications (entertainment, virtual reality) to simulation systems (driving, flying, and space simulators) and safety analyses (driving conditions, sign visibility). This article surveys global illumination algorithms for environments including participating media.(More)
BACKGROUND & AIMS Abdominal bloating is a frequent symptom in various categories of patients; however, its origin is unclear. Our aim was to establish the mechanisms of abdominal bloating. METHODS The study evaluated 56 patients whose predominant symptom was abdominal bloating. Of these, 47 (44 female and 3 male; aged 19-74 years) were diagnosed with(More)
This paper surveys global illumination algorithms for environments including participating media and accounting for multiple scattering. The objective of this survey is the characterization of those methods: Identification of their base techniques, their assumptions, limitations and range of utilization. To this end, the algorithms are grouped into(More)
BACKGROUND AND AIMS Patients frequently complain of gas symptoms precipitated by meals, but the effect of early digestion on intestinal gas content remains unknown. Our aim was to determine the influence of meals on intestinal gas volume and distribution. METHODS First, we developed a CT image analysis program, based on independent software modules, to(More)
ÐA framework for the development of di€erent global illumination algorithms is presented: the SIR (Sistema de Iluminacio n Realista) architecture. It consists of a set of object-oriented components, which constitute a kernel, intended to be extended by software developers for the speci®c needs of photorealistic or physically based rendering algorithms. #(More)
Aiming at rendering high quality images robustly for general environments with simple algorithms, we use a two-pass method that accounts for the global illumination. In this paper we present the integration of a new gathering procedure in the rendering pass, that uses the approximate results obtained by a particle tracing method, an extension of the(More)
BACKGROUND AND AIM We previously showed that colonic gas infusion increases the girth and modifies the muscular activity of the anterior abdominal wall. We hypothesized that abdominal accommodation to volume loads is an active process instrumented by the coordinated activity of the anterior wall and the diaphragm. METHODS To increase intraabdominal volume(More)
BACKGROUND It is unknown if abdominal bloating is attributable to excess abdominal gas or improved by a prokinetic agent. AIMS To assess abdominal gas content in functional abdominal bloating and to ascertain the effect of a prokinetic agent on intestinal gas symptoms in these patients. METHODS In 20 patients, intra-abdominal gas content and symptoms(More)
RADStation3G is a software platform for cardiovascular image analysis and surgery planning. It provides image visualization and management in 2D, 3D and 3D+t; data storage (images or operational results) in a PACS (using DICOM); and exploitation of patients' data such as images and pathologies. Further, it provides support for computationally expensive(More)