A Monte Carlo method for accelerating the computation of animated radiosity sequences

Realistic rendering animation is known to be an expensive processing task when physically-based global illumination methods are used in order to improve illumination details. This paper presents an acceleration technique to compute animations in radiosity environments. The technique is based on an interpolated approach that exploits temporal coherence in radiosity. A fast global Monte Carlo pre-processing step is introduced to the whole computation of the animated sequence to select important frames. These are fully computed and used as a base for the interpolation of all the sequence. The approach is completely view-independent. Once the illumination is computed, it can be visualized by any animated camera. Results present significant high speed-ups showing that the technique could be an interesting alternative to deterministic methods for computing non-interactive radiosity animations for moderately complex scenario

A parametric-space-based scan-line algorithm for rendering of bicubic surfaces

A novel scan-line algorithm for displaying bicubic surfaces is presented. Patches are decomposed on regions of constant sign of the z component of the normal before the scan process. Most of the computations are done in parametric space. The algorithm computes the intersection of the surfaces with only a restricted subset of scan planes and obtains the intersection with other scan planes by linear interpolation between exact intersections. A bound of the algorithm's error is given. The method is compared with Whitted's algorithm.Postprint (published version

On Improving Urban Environment Representations

Computer Graphics has evolved into a mature and powerful field that offers many opportunities to enhance different disciplines, adapting to the specific needs of each. One of these important fields is the design and analysis of Urban Environments. In this article we try to offer a perspective of one of the sectors identified in Urban Environment studies: Urbanization. More precisely we focus on geometric and appearance modeling, rendering and simulation tools to help stakeholders in key decision stages of the process

Fiber-Optic-Based System for High-Resolution Monitoring of Stretch in Excised Tissues

Cardiovascular diseases cause a high number of deaths nowadays. To improve these statistics, new strategies to better understand the electrical and mechanical abnormalities underlying them are urgently required. This study focuses on the development of a sensor to measure tissue stretch in excised tissues, enabling improved knowledge of biomechanical properties and allowing greater control in real time. A system made of biocompatible materials is described, which is based on two cantilevered platforms that integrate an optical fiber inside them to quantify the amount of stretch the tissues are exposed to with a precision of μm. The operating principle of the sensor is based on the variation of the optical path with the movement of the platforms onto which the samples are fixed. The conducted tests highlight that this system, based on a simple topology and technology, is capable of achieving the desired purpose (a resolution of ∼1 μm), enabling the tissue to be bathed in any medium within the system

Towards Efficient Parallel Radiosity for DSM-based Parallel Computers Using Virtual Interfaces

This paper presents the performance evaluation of a new technique for radiosity computation which aims at exploiting efficiently the different levels of a memory hierarchy of both sequential and parallel computers. Such ability is essential when dealing with complex environments having several millions of polygons. The principle of our technique is to split the initial environment into several sub-environments and compute the radiosity within each sub-environment. Exchange of energy between sub-environments is performed by means of virtual interfaces and visibility masks. The size of sub-environments can be adapted in order to fit into a cache or a local memory. We performed several experiments using an SGI Origin 2000 to show the effectiveness of our solution. It improves both the sequential and parallel execution of a progressive radiosity algorithm. Our technique decreases the execution time on one processor of an SGI Origin 2000 by a factor of more than 5 and leads to a very good efficiency for complex environments (1 million of polygons) on a multiprocessor configuration

Automated digital color restitution of mural paintings using minimal art historian input

Digital color restitution aims to digitally restore the original colors of a painting. Existing image editing applications can be used for this purpose, but they require a select-and-edit workflow and thus they do not scale well to large collections of paintings or different regions of the same painting. To address this issue, we propose an automated workflow that requires only a few representative source colors and associated target colors as input from art historians. The system then creates a control grid to model a deformation of the CIELAB color space. Such deformation can be applied to arbitrary images of the same painting. The proposed approach is suitable for restituting the color of images from a large photographic campaign, as well as for the textures of 3D reconstructions of a monument. We demonstrate the benefits of our method on a collection of mural paintings from a medieval monument.This work has been partially supported by projects PID2021-122136OB-C21 and PID2021-122136OB-C22 funded by MCIN/AEI/ 10.13039/501100011033 and by ERDF A way of making Europe, by the EU Horizon 2020, JPICH Conservation, Protection and Use initiative (JPICH-0127) and the Spanish Agencia Estatal de Investigación (grant PCI2020-111979).Peer ReviewedPostprint (published version