Reconhecimento de faces 3D com Kinect

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

3D superimposition and understanding temporomandibular joint arthritis

Structured AbstractObjectivesTo investigate the 3D morphological variations in 169 temporomandibular ioint (TMJ) condyles, using novel imaging statistical modeling approaches.Setting and sample populationThe Department of Orthodontics and Pediatric Dentistry at the University of Michigan. Cone beam CT scans were acquired from 69 subjects with long-term TMJ osteoarthritis (OA, mean age 39.115.7years), 15 subjects at initial consult diagnosis of OA (mean age 44.914.8years), and seven healthy controls (mean age 4312.4years).Materials and methods3D surface models of the condyles were constructed, and homologous correspondent points on each model were established. The statistical framework included Direction-Projection-Permutation (DiProPerm) for testing statistical significance of the differences between healthy controls and the OA groups determined by clinical and radiographic diagnoses.ResultsCondylar morphology in OA and healthy subjects varied widely with categorization from mild to severe bone degeneration or overgrowth. DiProPerm statistics supported a significant difference between the healthy control group and the initial diagnosis of OA group (t=6.6, empirical p-value=0.006) and between healthy and long-term diagnosis of OA group (t=7.2, empirical p-value=0). Compared with healthy controls, the average condyle in OA subjects was significantly smaller in all dimensions, except its anterior surface, even in subjects with initial diagnosis of OA.ConclusionThis new statistical modeling of condylar morphology allows the development of more targeted classifications of this condition than previously possible.

Superconducting properties of a parallelepiped mesoscopic superconductor: a comparative study between the 2D and 3D Ginzburg-Landau models

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A virtual experiment for the detection of specific features in the frequency response of a coupled nonlinear and linear oscillator

This paper presents an investigation into some practical issues that may be present in a real experiment, when trying to validate the theoretical frequency response curve of a two degree-of-freedom nonlinear system consisting of coupled linear and nonlinear oscillators. Some specific features, such as detached resonance curves, have been theoretically predicted in multi degree-of-freedom nonlinear oscillators, when subject to harmonic excitation, and the system parameters have been shown to be fundamental in achieving such features. When based on a simplified model, approximate analytical expression for the frequency response curves may be derived, which may be validated by the numerical solutions. In a real experiment, however, the practical achievability of such features was previously shown to be greatly affected by small disturbances induced by gravity and inertia, which led to some solutions becoming unstable which had been predicted to be stable. In this work a practical system configuration is proposed where such effects are reduced so that the previous limitations are overcome. A virtual experiment is carried out where a detailed multi-body model of the oscillator is assembled and the effects on the system response are investigated.

Análise Biomecânica em implantes com diferentes tipos de conexão: estudo pelo MEF-3D

The aim of this study was to evaluate the biomechanical behavior of different implant connection types, by means of three-dimensional finite element analysis. 3 Three-dimensional models were created with a graphic modeling software: SolidWorks 2006 and Rhinoceros 4.0, and InVesalius (CTI, São Paulo, Brasil), the bone was obtained by computerized tomography of a sagittal section of the molar region. The model was composed by bone block with an implant (4 x 10 mm) (Conexão Sistemas de Prótese, São Paulo), with different implant connections: external hex, internal hex and Morse-taper with the corresponding prosthetic component Ucla or Morse-taper abutment. The Three-dimensional models were transferred to finite element software Femap 10.0 (Siemens PLM Software Inc., CA, USA), to generate a mesh, boundary conditions and loading. An axial (200N) and oblique load (100N) was applied on the occlusal surface of the crowns. Analyses were performed using the finite element software NEiNastran 9.0 (Noran Engineering, Inc., USA) and transferred to the Femap 10.0 to obtain the results; after the results were visualized using von Mises stress maps and Maximum stress principal. The results showed the stress distribution was similar between models, with a little superiority of Morse-taper connection. It was concluded that: the three connection types were biomechanical viable; The Morse-taper connection presented the better internal stress distribution; there was not significant biomechanical differences on the bone.

Análise da distribuição de tensões em reabilitação com implantes cone morse em maxilar posterior: estudo pelo MEF 3D não linear

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise e aferição de uma fresadora CNC através da utilização das tecnologias assistidas por computador, no escaneamento 3D de amostras e processamento de imagens

The use of computer-assisted technologies such as CAD - Computed Aided Design, CAM - Computed Aided Manufacturing, CAE - Computed Aided Engineering and CNC - Computed Numerical Control, are priorities in engineering and product designers. However, the dimensional measurement between the virtual and the real product design requires research, and dissemination procedures among its users. This work aims to use these technologies, through analysis and measurement of a CNC milling machine, designed and assembled in the university. Through the use of 3D scanning, and analyzing images of the machined samples, and its original virtual files, it was possible to compare the sizes of these samples in counterposition to the original virtual dimensions, we can state that the distortions between the real and virtual, are within acceptable limits for this type of equipment. As a secondary objective, this work seeks to disseminate and make more accessible the use of these technologies.

Interação com objetos digitais 3D em estúdios virtuais

Pós-graduação em Televisão Digital: Informação e Conhecimento - FAAC

A palaeobiologist's guide to 'virtual' micro-CT preparation

This paper provides a brief but comprehensive guide to creating, preparing and dissecting a 'virtual' fossil, using a worked example to demonstrate some standard data processing techniques. Computed tomography (CT) is a 3D imaging modality for producing 'virtual' models of an object on a computer. In the last decade, CT technology has greatly improved, allowing bigger and denser objects to be scanned increasingly rapidly. The technique has now reached a stage where systems can facilitate large-scale, non-destructive comparative studies of extinct fossils and their living relatives. Consequently the main limiting factor in CT-based analyses is no longer scanning, but the hurdles of data processing (see disclaimer). The latter comprises the techniques required to convert a 3D CT volume (stack of digital slices) into a virtual image of the fossil that can be prepared (separated) from the matrix and 'dissected' into its anatomical parts. This technique can be applied to specimens or part of specimens embedded in the rock matrix that until now have been otherwise impossible to visualise. This paper presents a suggested workflow explaining the steps required, using as example a fossil tooth of Sphenacanthus hybodoides (Egerton), a shark from the Late Carboniferous of England. The original NHMUK copyrighted CT slice stack can be downloaded for practice of the described techniques, which include segmentation, rendering, movie animation, stereo-anaglyphy, data storage and dissemination. Fragile, rare specimens and type materials in university and museum collections can therefore be virtually processed for a variety of purposes, including virtual loans, website illustrations, publications and digital collections. Micro-CT and other 3D imaging techniques are increasingly utilized to facilitate data sharing among scientists and on education and outreach projects. Hence there is the potential to usher in a new era of global scientific collaboration and public communication using specimens in museum collections.

Case study: a 3D resistivity and induced polarization imaging from downstream a waste disposal site in Brazil

A contaminated site from a downstream municipal solid waste disposal site in Brazil was investigated by using a 3D resistivity and induced polarization (IP) imaging technique. This investigation purpose was to detect and delineate contamination plume produced by wastes. The area was selected based on previous geophysical investigations, and chemical analyses carried out in the site, indicating the presence of a contamination plume in the area. Resistivity model has successfully imaged waste presence (rho < 20 Omega m), water table depth, and groundwater flow direction. A conductive anomaly (rho < 20 Omega m) outside wastes placement was interpreted as a contamination plume. Chargeability model was also able to imaging waste presence (m > 31 mV/V), water table depth, and groundwater flow direction. A higher chargeability zone (m > 31 mV/V) outside wastes placement and following conductive anomaly was interpreted as a contamination plume. Normalized chargeability (MN = m/rho) confirmed polarizable zone, which could be an effect of a salinity increase (contamination plume), and the clay presence in the environment.

Finite element analysis of bonded model Class I 'restorations' after shrinkage

Objectives. The C-Factor has been used widely to rationalize the changes in shrinkage stress occurring at the tooth/resin-composite interfaces. Experimentally, such stresses have been measured in a uniaxial direction between opposed parallel walls. The situation of adjoining cavity walls has been neglected. The aim was to investigate the hypothesis that: within stylized model rectangular cavities of constant volume and wall thickness, the interfacial shrinkage-stress at the adjoining cavity walls increases steadily as the C-Factor increases. Methods. Eight 3D-FEM restored Class I 'rectangular cavity' models were created by MSC.PATRAN/MSC.Marc, r2-2005 and subjected to 1% of shrinkage, while maintaining constant both the volume (20 mm(3)) and the wall thickness (2 mm), but varying the C-Factor (1.9-13.5). An adhesive contact between the composite and the teeth was incorporated. Polymerization shrinkage was simulated by analogy with thermal contraction. Principal stresses and strains were calculated. Peak values of maximum principal (MP) and maximum shear (MS) stresses from the different walls were displayed graphically as a function of C-Factor. The stress-peak association with C-Factor was evaluated by the Pearson correlation between the stress peak and the C-Factor. Results. The hypothesis was rejected: there was no clear increase of stress-peaks with C-Factor. The stress-peaks particularly expressed as MP and MS varied only slightly with increasing C-Factor. Lower stress-peaks were present at the pulpal floor in comparison to the stress at the axial walls. In general, MP and MS were similar when the axial wall dimensions were similar. The Pearson coefficient only expressed associations for the maximum principal stress at the ZX wall and the Z axis. Significance. Increase of the C-Factor did not lead to increase of the calculated stress-peaks in model rectangular Class I cavity walls. (C) 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Loudness scattering due to vibro-acoustic model variability

The use of numerical simulation in the design and evaluation of products performance is ever increasing. To a greater extent, such estimates are needed in a early design stage, when physical prototypes are not available. When dealing with vibro-acoustic models, known to be computationally expensive, a question remains, which is related to the accuracy of such models in view of the well-know variability inherent to the mass manufacturing production techniques. In addition, both academia and industry have recently realized the importance of actually listening to a products sound, either by measurements or by virtual sound synthesis, in order to assess its performance. In this work, the scatter of significant parameter variations on a simplified vehicle vibro-acoustic model is calculated on loudness metrics using Monte Carlo analysis. The mapping from the system parameters to sound quality metric is performed by a fully-coupled vibro-acoustic finite element model. Different loudness metrics are used, including overall sound pressure level expressed in dB and Specific Loudness in Sones. Sound quality equivalent sources are used to excite this model and the sound pressure level at the driver's head position is acquired to be evaluated according to sound quality metrics. No significant variation has been perceived when evaluating the system using regular sound pressure level expressed in in dB and dB(A). This happens because of the third-octave filters that averages the results under some frequency bands. On the other hand, Zwicker Loudness presents important variations, arguably, due to the masking effects.

Performance Optimization of a Floating Breakwater Model Using SPH Method, with a Practical Application

Máster en Oceanografía

Entorno de desarrollo con software libre para aplicaciones goegráficas 3D

[ES] La superficie afectada por incendios en Gran Canaria y Tenerife en Agosto de 2007 (aproximadamente 35.060 hectáreas) fue similar a la quemada en los últimos 22 años en todo el Archipiélago Canario. Sin duda, en los momentos clave de incen-dios, cuando la prevención se ha visto desbordada, se impone una planificación y actuación en base a simulaciones predicti-vas que ayuden a minimizar los daños ocasionados. Los gestores virtuales por ordenador pretenden ser herramientas de ayu-da en este propósito. Se presenta un entorno de desarrollo robusto, funcional y flexible encaminado a crear aplicaciones geográficas 3D mul-ticapa centrado, en esta etapa de desarrollo, en la aplicación a un Gestor Virtual de Emergencias1 (Geviemer) con la capaci-dad de simulación y predicción del fuego en incendios forestales. Se ofrece una herramienta de utilidad para el análisis y la toma de decisiones en incendios en Canarias, con una visualización tridimensional que permite la interacción en tiempo real. El entorno, desarrollado con software libre y diseñado en base a una arquitectura por capas permite adaptarlo completa-mente a las necesidades del usuario, ofreciendo un marco abierto a la especialización en aplicaciones concretas. Se analizan en esta comunicación los pormenores del entorno, destacando las características del diseño del software y las particularida-des de Geviemer.

Regularization of 3D cylindrical surfaces

[EN] In this paper we present a method for the regularization of 3D cylindrical surfaces. By a cylindrical surface we mean a 3D surface that can be expressed as an application S(l; µ) ! R3 , where (l; µ) represents a cylindrical parametrization of the 3D surface. We built an initial cylindrical parametrization of the surface. We propose a new method to regularize such cylindrical surface. This method takes into account the information supplied by the disparity maps computed between pair of images to constraint the regularization of the set of 3D points. We propose a model based on an energy which is composed of two terms: an attachment term that minimizes the difference between the image coordinates and the disparity maps and a second term that enables a regularization by means of anisotropic diffusion. One interesting advantage of this approach is that we regularize the 3D surface by using a bi-dimensional minimization problem.