Instituto de Informática

Resumo: Este artigo tem por objetivo apresentar a metodologia de desenvolvimento ágil de software denominada Extreme Programming. Serão abordadas, de forma resumida, as práticas, valores, e os papéis disponíveis a cada integrante de uma equipe de XP. Alguns comparativos com outras metodologias são feitas ao decorrer do trabalho enaltecendo as propriedades que definem a Extreme Programming.

Data gloves are devices equipped with sensors that capture the movements of the hand of the user in order to select or manipulate objects in a virtual world. Data gloves were introduced three decades ago and since then have been used in many 3D interaction techniques. However, good data gloves are too expensive and only a few of them can perceive the full set of hand movements. In this paper we describe the design of an image-based data glove (IBDG) prototype suitable for finger sensible applications, like virtual objects manipulation and interaction approaches. The proposed device uses a camera to track visual markers at finger tips, and a software module to compute the position of each finger tip and its joints in real-time. To evaluate our concept, we have built a prototype and tested it with 15 volunteers. We also discuss how to improve the engineering of the prototype, how to turn it into a low cost interaction device, as well as other relevant issues about this original

We introduce tailored displays that enhance visual acuity by decomposing virtual objects and placing the resulting anisotropic pieces into the subject's focal range. The goal is to free the viewer from needing wearable optical corrections when looking at displays. Our tailoring process uses aberration and scattering maps to account for refractive errors and cataracts. It splits an object's light field into multiple instances that are each in-focus for a given eye subaperture. Their integration onto the retina leads to a quality improvement of perceived images when observing the display with naked eyes. The use of multiple depths to render each point of focus on the retina creates multi-focus, multi-depth displays. User evaluations and validation with modified camera optics are performed. We propose tailored displays for daily tasks where using eyeglasses are unfeasible or inconvenient (e.g., on head-mounted displays, ereaders, as well as for games); when a multi-focus function is required but undoable (e.g., driving for farsighted individuals, checking a portable device while doing physical activities); or for correcting the visual distortions produced by high-order aberrations that eyeglasses are not able to.

Categoria: Engenharia de Software. Linguagem de programação: Java Sistema operacional: Qualquer um que suporte JRE 1.4 Palavras-chave: Extreme Programming, Engenharia de Software, Qualidade de Software, Metodologia de Desenvolvimento, Processos Ágeis de Desenvolvimento, XP, Requisitos de Software.

Categoria: Engenharia de Software. Linguagem de programação: Java Sistema operacional: Qualquer um que suporte JRE 1.4 Palavras-chave: Extreme Programming, Engenharia de Software, Qualidade de Software, Metodologia de Desenvolvimento, Processos Ágeis de Desenvolvimento, XP, Requisitos de Software.

We introduce an interactive method to assess cataracts in the human eye by crafting an optical solution that measures the perceptual impact of forward scattering on the foveal region. Current solutions rely on highly-trained clinicians to check the back scattering in the crystallin lens and test their predictions on visual acuity tests. Close-range parallax barriers create collimated beams of light to scan through sub-apertures, scattering light as it strikes a cataract. User feedback generates maps for opacity, attenuation, contrast and sub-aperture point-spread functions. The goal is to allow a general audience to operate a portable high-contrast light-field display to gain a meaningful understanding of their own visual conditions. User evaluations and validation with modified camera optics are performed. Compiled data is used to reconstruct the individual's cataract-affected view, offering a novel approach for capturing information for screening, diagnostic, and clinical analysis.

We introduce a physiologically-based model for pupil light reflex (PLR) and an image-based model for iridal pattern deformation. Our PLR model expresses the pupil diameter as a function of the environment lighting, and is described by a delay-differential equation, naturally adapting the pupil diameter even to abrupt changes in light conditions. Since the parameters of our PLR model were derived from measured data, it correctly simulates the actual behavior of the human pupil. Another contribution of our work is a model for realist deformation of the iris pattern as a function of pupil dilation and constriction. Our models produce high-fidelity appearance effects and can be used to produce real-time predictive animations of the pupil and iris under variable lighting conditions. We assess the predictability and quality of our simulations through comparisons of modeled results against measured data derived from experiments also described in this work. Combined, our models can bring facial animation to new photorealistic standards.

We introduce an interactive, portable, and inexpensive solution for estimating refractive errors in the human eye. While expensive optical devices for automatic estimation of refractive correction exist, our goal is to greatly simplify the mechanism by putting the human subject in the loop. Our solution is based on a high-resolution programmable display and combines inexpensive optical elements, interactive GUI, and computational reconstruction. The key idea is to interface a lenticular view-dependent display with the human eye in close range -a few millimeters apart. Via this platform, we create a new range of interactivity that is extremely sensitive to parameters of the human eye, like refractive errors, focal range, focusing speed, lens opacity, etc. We propose several simple optical setups, verify their accuracy, precision, and validate them in a user study.

We introduce an interactive, portable, and inexpensive solution for estimating refractive errors in the human eye. While expensive optical devices for automatic estimation of refractive correction exist, our goal is to greatly simplify the mechanism by putting the human subject in the loop. Our solution is based on a high-resolution programmable display and combines inexpensive optical elements, interactive GUI, and computational reconstruction. The key idea is to interface a lenticular view-dependent display with the human eye in close range -a few millimeters apart. Via this platform, we create a new range of interactivity that is extremely sensitive to parameters of the human eye, like refractive errors, focal range, focusing speed, lens opacity, etc. We propose several simple optical setups, verify their accuracy, precision, and validate them in a user study.

Nosúltimos anos, jogos 3D para celulares têm recebido significativa atenção dos pesquisadores e incentivos fiscais do estado brasileiro. Ainda longe da qualidade gráfica dos jogos para computadores e consoles, os jogos para celulares, que sofrem pela severa limitação de memória e processamento dos aparelhos modernos, caminham a passos lentos. Recentes investidas contra estas difuldades criaram motores de jogos [Gomes and Pamplona 2005], [de Albuquerque Macêdo Jr. 2005] com a finalidade de facilitar o desenvolvimento e otimizar os jogos. Este trabalho apresenta a implementação do módulo de importação e visualização de Personagens Não Jogador (PNJs) em um dos motores de jogos citados anteriormente, o Mobile 3D Game Engine (M3GE). Desta forma, foi adicionado o suporte a um formato de modelos chamado Quake II's Models (MD2), muito utilizado para a modelagem de personagens para jogos, pois incorpora recursos de animação quadro a quadro. O trabalho não discute questões relativasà inteligência dos PNJs. São apresentados detalhes da implementação de importação e visualização dos modelos, bem como a demonstração de exemplos e testes de desempenho de forma a validar a solução proposta.

We introduce a physiologically-based model for pupil light reflex (PLR) and an image-based model for iridal pattern deformation. Our timedependent PLR model expresses the pupil diameter as a function of the environment lighting, naturally adapting the pupil diameter even to abrupt changes in lighting conditions. Since the parameters of our PLR model were derived from measured data, it correctly simulates the actual behavior of the human pupil. Another contribution of our work is a model for realist deformation of the iris pattern as a function of pupil size. Our models produce high-fidelity appearance effects and can be used to produce real-time predictive animations of the pupil and iris under variable lighting conditions. We assess the predictability and quality of our simulations through comparisons of modeled results against measured data derived from experiments. Combined, our models can bring facial animation to new photorealistic standards.