Saulo A. Pessoa

Photorealistic rendering for Augmented Reality: A global illumination and BRDF solution

This paper presents a solution for the photorealistic rendering of synthetic objects into dynamic real scenes, in Augmented Reality applications. In order to achieve this goal, an Image Based Lighting approach is used, where environment maps with different levels of glossiness are generated for each virtual object in the scene at every frame. Due to this, illumination effects, such as color bleeding and specular reflections, can be simulated for virtual objects in a consistent way. A unifying sampling method for the spherical harmonics transformation pass is also used. It is independent of map format and does not need to apply different weights for each sample. The developed technique is combined with an extended version of Lafortune Spatial BRDF, featuring Fresnel effect and an innovative tangent rotation parameterization. The solution is evaluated in various Augmented Reality case studies, where other features like shadowing and lens effects are also exploited.

Virtual Reality in Brazil 2011: RPR-SORS: Real-time photorealistic rendering of synthetic objects into real scenes

This paper presents a review of the Photorealistic Augmented Reality field and proposes a solution for interactively rendering virtual objects into dynamic real scenes in a photorealistic way. This solution features a rendering pipeline that comprises techniques regarding illumination, reflectance model, shadowing, composition, and camera effects. The techniques are chained in a flexible way, allowing the user to choose which techniques are to be enabled. An environment map generation procedure was developed and allows virtual objects to exhibit coherent effects such as color bleeding and specular reflection, even when the real objects are moved. The range of materials that can be rendered was widened by extending Lafortunes Spatial BRDF. The implemented infrastructure is offered as an authoring toolkit that consists of an API and a material editor tool. The aim of this authoring toolkit is to increase development productivity of Photorealistic Augmented Reality applications. The proposed solution was evaluated by taking into account visual and performance metrics. It allowed consistent rendering of dynamic scenes and photorealistic materials. The frame rate obtained was suitable to Augmented Reality applications when there were few virtual objects in the scene.

RPR-SORS: An Authoring Toolkit for Photorealistic AR

This paper presents a solution for photorealistic rendering of virtual objects into dynamic real scenes. It consists of a toolkit for Augmented Reality, named RPR- SORS, which is composed of two artifacts: an API that handles various computer graphics techniques in a novel pipeline approaching illumination, reflectance model, shadowing, composition, and camera effects; and a material editor that accelerates the creation of complex photorealistic materials. An experimental application was developed with the proposed solution, where both the API and material editor were used to accomplish photorealistic effects in an application of Augmented Reality in architecture. The results obtained show that the API provides a flexible infrastructure for the photorealistic Augmented Reality pipeline, and that the material editor facilitates the creation of photorealistic materials and their use for Augmented Reality

A Global Illumination and BRDF Solution Applied to Photorealistic Augmented Reality

This paper presents a solution for the photorealistic rendering of synthetic objects into dynamic real scenes, in Augmented Reality applications. In order to achieve this goal, an Image Based Lighting approach is proposed, where environment maps with different levels of glossiness are generated for each virtual object in the scene at every frame. Due to this, illumination effects, such as color bleeding and specular reflections, can be simulated for virtual objects in a consistent way, even under the presence of scene changes. A unifying sampling method for the spherical harmonics transformation pass is also used. It is independent of map format and does not need to apply different weights for each sample. The developed technique is combined with an extended version of Lafortune Spatial BRDF, featuring Fresnel effect and an innovative tangent rotation parameterization. The solution is evaluated in various Augmented Reality case studies, where other features like shadowing and lens effects are also exploited.

Stereo Tracking and 3D Reconstruction of Underwater Pipes.

Installing flexible oil pipes in deep underwater environments is a risky operation, which is currently monitored by manually comparing the geometric conditions to the simulated studies. In order to avoid this error-prone assessment, this paper proposes an algorithm to track and reconstruct the pipe medial axis using stereo cameras. By taking advantage of the scenario illumination and the pipe texture, it is possible to devise an energy maximization approach that efficiently tracks the pipe. The reconstruction technique is an enhancement over a state-of-the-art B-spline reconstruction algorithm, specializing it for plane curves. Experiments on synthetic and laboratory videos report a very low mean tracking and reconstruction errors, while there are strong evidences of the robustness on a real scenario.