An augmented reality pipeline to create scenes with coherent illumination using textured cuboids

Shadows and illumination play an important role when generating a realistic scene in computer graphics. Most of the Augmented Reality (AR) systems track markers placed in a real scene and retrieve their position and orientation to serve as a frame of reference for added computer generated content, thereby producing an augmented scene. Realistic depiction of augmented content with coherent visual cues is a desired goal in many AR applications. However, rendering an augmented scene with realistic illumination is a complex task. Many existent approaches rely on a non automated pre-processing phase to retrieve illumination parameters from the scene. Other techniques rely on specific markers that contain light probes to perform environment lighting estimation. This study aims at designing a method to create AR applications with coherent illumination and shadows, using a textured cuboid marker, that does not require a training phase to provide lighting information. Such marker may be easily found in common environments: most of product packaging satisfies such characteristics. Thus, we propose a way to estimate a directional light configuration using multiple texture tracking to render AR scenes in a realistic fashion. We also propose a novel feature descriptor that is used to perform multiple texture tracking. Our descriptor is an extension of the binary descriptor, named discrete descriptor, and outperforms current state-of-the-art methods in speed, while maintaining their accuracy.

Realidade aumentada aplicada em bibliotecas: multiplicidade no acesso a informação

Conceitua Realidade Aumentada do ponto de vista histórico de vários autores e como surgiu esse segmento através da evolução tecnológica até os dias atuais. Aborda seu funcionamento, como também, seus sistemas e aplicações em diversos campos de pesquisas e estudos científicos. Diferencia Realidade Aumentada de Realidade Virtual, visando melhor esclarecimento entre ambas na intenção de descaracterizá-las com uma única “realidade”. Apresenta a Realidade Aumentada e sua aplicação dentro de um contexto de uma unidade de informação, promovendo uma melhor interação com os usuários e as adaptações pelas quais as bibliotecas terão que passar futuramente para se adequarem a “explosão” tecnológica. Descreve o funcionamento da biblioteca ARToolKIT, baseada em RA e suas principais etapas de funcionamento para visualização de objetos virtuais em 3D. Exemplifica os benefícios que uma unidade de informação, que utiliza Realidade Aumentada, promove aos usuários portadores de deficiência, além de sua inclusão no meio digital e sua inserção no mercado de trabalho

Odometria visual baseada em técnicas de structure from motion

Visual Odometry is the process that estimates camera position and orientation based solely on images and in features (projections of visual landmarks present in the scene) extraced from them. With the increasing advance of Computer Vision algorithms and computer processing power, the subarea known as Structure from Motion (SFM) started to supply mathematical tools composing localization systems for robotics and Augmented Reality applications, in contrast with its initial purpose of being used in inherently offline solutions aiming 3D reconstruction and image based modelling. In that way, this work proposes a pipeline to obtain relative position featuring a previously calibrated camera as positional sensor and based entirely on models and algorithms from SFM. Techniques usually applied in camera localization systems such as Kalman filters and particle filters are not used, making unnecessary additional information like probabilistic models for camera state transition. Experiments assessing both 3D reconstruction quality and camera position estimated by the system were performed, in which image sequences captured in reallistic scenarios were processed and compared to localization data gathered from a mobile robotic platform

Realidade aumentada aplicada em bibliotecas: multiplicidade no acesso a informação

Conceitua Realidade Aumentada do ponto de vista histórico de vários autores e como surgiu esse segmento através da evolução tecnológica até os dias atuais. Aborda seu funcionamento, como também, seus sistemas e aplicações em diversos campos de pesquisas e estudos científicos. Diferencia Realidade Aumentada de Realidade Virtual, visando melhor esclarecimento entre ambas na intenção de descaracterizá-las com uma única “realidade”. Apresenta a Realidade Aumentada e sua aplicação dentro de um contexto de uma unidade de informação, promovendo uma melhor interação com os usuários e as adaptações pelas quais as bibliotecas terão que passar futuramente para se adequarem a “explosão” tecnológica. Descreve o funcionamento da biblioteca ARToolKIT, baseada em RA e suas principais etapas de funcionamento para visualização de objetos virtuais em 3D. Exemplifica os benefícios que uma unidade de informação, que utiliza Realidade Aumentada, promove aos usuários portadores de deficiência, além de sua inclusão no meio digital e sua inserção no mercado de trabalho

Sociedade civil no espaço de atuação com juventude: uma cartografia social

This report has as its objective the setting up of a social cartography, mapping and characterizing non-governmental organizations working with adolescents and young people (OSC) in the western districts of the city of Natal. Characteristics such as the profile, themes and principal activities, how the organizations fit into the public sector and their participation in social networks are observed. Thus common differences and similarities which serve as a means of indentification, take as reference the symbolic cartography of Boaventura of Sousa Santos. Since there are relatively few studies relating to civil society of Rio Grande do Norte and in particular, Natal, the starting point was the setting up of a database allowing for a general overview. Hence a panorama of the organizations could be observed: where they are located, when they were formed how they operate and their relationships with other sectors (the state, the market and civil society) in addition to basic facts and location. The principal lines of enquiry were a) the OSC which operate with the public comprising adolescents and young people and b) the OSC operating or having branches in four suburbs on the periphery of the western administrative region of the city (Felipe Camarão, Bom Pastor, Cidade Nova and Guararapes).The present report has identified the impacts of ongoing social transformation caused by the process of globalization ,by the various currently contested political projects which are as follows: the project of neoliberal globalized capitalism(hegemonic)and the project of social emancipation (contra-hegemonic),how these are seen from the local viewpoint and how they influence the profiles and operation of the cartographic organizations. The area of the OSC is a heterogenous one with political, cultural and ideological strains, characterized by its infiltration, its local/global and multicultural dimensions. As civil organizations are fundamental in the processes of transformation within society, and following the idea of social emancipation referred to by Boaventura Santos, the enquiry classified the organizations according to the afore-mentioned characteristics, establishing eight types of associations. These different types and their respective characteristics were analysed from a related perspective using the mechanisms of symbolic cartography: scale, projection and symbolisation. The theoretical references underpinning this research arise from the debate on civil society which becomes redefined as a result of the dispute involving the two afore-mentioned political projects. These demand the theoretical application of the comprehension of heterogeneity in its diversity and complexity together with the idea of social emancipation.The main authors consulted were Boaventura de Sousa Santos, Antonio Gramsci, through the texts translated by Marco Aurelio Nogueira; Carlos Nelson Coutinho and Alberto Rivera ,who supported the construction of the types of associations identified by the local reality.Finally this research enabled an understanding of the current form of social action happening in the Space of the Four Neighbourhoods (Espaço dos 4 Bairros) and how the distinct profiles analysed together with the ares of operation of the organizations define their emancipatory potencials within the following two poles: regulation/adaptation and emancipation/transformation