Portuguese Meeting on Computer Graphics 2011 - SIACG 2011

Permanent URI for this collection

ISBN 978-3-03868-152-6
Data Visualization
Digital Cartographic Generalization in Spatial Databases: application issues in Power Grids CAD tools
Javier Novo Rodríguez, Elena Hernández Pereira, and Mariano Cabrero Canosa
3D Visualization of Sparse Geophysical Data Representing Uncertainty
Vítor Gonçalves, Paulo Dias, Fernando Almeida, Joaquim Madeira, and Beatriz Sousa Santos
Interactive Visualizations of Automatic Debugging Reports
André Riboira, Rui Rodrigues, and Rui Abreu
GraphJudge: A System for Assisted Assessment of Computer Graphics Assignments
Lindomar Rocha and Rui Rodrigues
DatData Visualization
Neural Data Exploration with Force Feedback
Laura Raya, Miguel A. Otaduy, and Marcos García
Data Visualization
Interacting with Outdoor Sports Performance Data
J. M. Brisson Lopes
Lights Fields and Image Processing
High-quality Compression of Mipmapped Textures
C. Andujar
Non-Uniform Spherical Light Fields
J. Blasco, F. Abad, E. Camahort, and R. Vivó
Graph-Based Reflectance Segmentation
Elena Garces, Diego Gutierrez, and Jorge Lopez-Moreno
Efficient Propagation of Light Field Edits
Adrian Jarabo, Belen Masia, and Diego Gutierrez
Cortical 3D Face Recognition Framework
J. Rodrigues, R. Lam, and J. du Buf
Displays and Computational Photography
BlenderCAVE: Easy VR Authoring for Multi-Screen Displays
Jorge Gascón, José M. Bayona, José M. Espadero, and Miguel A. Otaduy
Coded Apertures for Defocus Deblurring
Belen Masia, Adrian Corrales, Lara Presa, and Diego Gutierrez
Mobile Computational Photography: Exposure Fusion on the Nokia N900
Jose I. Echevarria and Diego Gutierrez
HaloDot: Visualization of the Relevance of Off-Screen Objects
Tiago Gonçalves, Ana Paula Afonso, Maria Beatriz Carmo, and Paulo Pombinho
Inexpensive 3D Stereo for Two Users Using a Single Display
Armando de la Re, Eduardo Martorell, Emilio Camahort, and Francisco Abad
Modeling and Simulation
A Simple Surface Tracking Method for Physically-Based 3D Water Simulations
G. Amador and A. Gomes
Procedural Modeling of Suspension Bridges
Gustavo Patow
Real-Time Modelling and Rendering of Sprayed Concrete
G. Vélez, L. Matey, A. Amundarain, F. Ordás, and J.A. Marín
Procedural Modelling of Destructible Materials
J. van Gestel and R. Bidarra
GPU Collision Detection in Conformal Geometric Space
Eduardo Roa, Víctor Theoktisto, Marta Fairén, and Isabel Navazo
Parallel Collision Detection Oriented to Distributed Memory Architectures for High-Resolution Meshes
Marcos Novalbos and Alberto Sánchez
3D Modeling and Interaction
Linear-Time Dynamics of Characters with Stiff Joints
Fernando Hernández, Carlos Garre, Rubén Casillas, and Miguel A. Otaduy
Interactive Elastic Deformation of 3D Images
Francisco J. R. Prados, Alejandro León Salas, and Juan Carlos Torres
Volume-Surface Collision Detection
J. Ortegano, H. Navarro, and R. Carmona
Augmented Reality for Web - A New Interaction Method Without Markers
Luis F. A. Silva and Frutuoso G. M. Silva
Robust Method for Estimating Normals on Point Clouds Using Adaptive Neighborhood Size
E.A. Leal and N.E. Leal
3DWikiU - 3D Wiki For Urban Environments
M. Melo, P. Silva, L. Magalhães, M. Bessa, A. Coelho, J. Moura, A. Rocha, F. Ferreira, J. Cruz, and A. Sousa
Medical Data Visualization
A Moving Least Squares Method for Implant Model Deformation in Computer Aided Orthopedic Surgery for Fractures of Lower Extremities
Esmitt Ramírez and Ernesto Coto
Investigating the Differences Between European Portuguese Sounds: An Approach Using Polygonal Mesh Comparison
Paula Martins, Samuel Silva, Catarina Oliveira, Carlos Ferreira, Augusto Silva, and António Teixeira
Left-Ventricle Global and Regional Functional Analysis from MDCT Images
Samuel Silva, Beatriz Sousa Santos, and Joaquim Madeira
A Colour Rotation Based Detector for Bleeding Gastric Pathologies
P. Coelho, A. Cunha, P. Costa, and L. Hadjileontiadis

BibTeX (Portuguese Meeting on Computer Graphics 2011 - SIACG 2011)
@inproceedings{
10.2312:pt.20111123,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Digital Cartographic Generalization in Spatial Databases: application issues in Power Grids CAD tools}},
author = {
Rodríguez, Javier Novo
 and
Pereira, Elena Hernández
 and
Canosa, Mariano Cabrero
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111123}
}
@inproceedings{
10.2312:pt.20111124,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
3D Visualization of Sparse Geophysical Data Representing Uncertainty}},
author = {
Gonçalves, Vítor
 and
Dias, Paulo
 and
Almeida, Fernando
 and
Madeira, Joaquim
 and
Santos, Beatriz Sousa
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111124}
}
@inproceedings{
10.2312:pt.20111125,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Interactive Visualizations of Automatic Debugging Reports}},
author = {
Riboira, André
 and
Rodrigues, Rui
 and
Abreu, Rui
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111125}
}
@inproceedings{
10.2312:pt.20111126,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
GraphJudge: A System for Assisted Assessment of Computer Graphics Assignments}},
author = {
Rocha, Lindomar
 and
Rodrigues, Rui
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111126}
}
@inproceedings{
10.2312:pt.20111127,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Neural Data Exploration with Force Feedback}},
author = {
Raya, Laura
 and
Otaduy, Miguel A.
 and
García, Marcos
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111127}
}
@inproceedings{
10.2312:pt.20111129,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
High-quality Compression of Mipmapped Textures}},
author = {
Andujar, C.
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111129}
}
@inproceedings{
10.2312:pt.20111131,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Graph-Based Reflectance Segmentation}},
author = {
Garces, Elena
 and
Gutierrez, Diego
 and
Lopez-Moreno, Jorge
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111131}
}
@inproceedings{
10.2312:pt.20111130,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Non-Uniform Spherical Light Fields}},
author = {
Blasco, J.
 and
Abad, F.
 and
Camahort, E.
 and
Vivó, R.
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111130}
}
@inproceedings{
10.2312:pt.20111128,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Interacting with Outdoor Sports Performance Data}},
author = {
Lopes, J. M. Brisson
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111128}
}
@inproceedings{
10.2312:pt.20111135,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Coded Apertures for Defocus Deblurring}},
author = {
Masia, Belen
 and
Corrales, Adrian
 and
Presa, Lara
 and
Gutierrez, Diego
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111135}
}
@inproceedings{
10.2312:pt.20111132,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Efficient Propagation of Light Field Edits}},
author = {
Jarabo, Adrian
 and
Masia, Belen
 and
Gutierrez, Diego
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111132}
}
@inproceedings{
10.2312:pt.20111133,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Cortical 3D Face Recognition Framework}},
author = {
Rodrigues, J.
 and
Lam, R.
 and
Buf, J. du
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111133}
}
@inproceedings{
10.2312:pt.20111134,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
BlenderCAVE: Easy VR Authoring for Multi-Screen Displays}},
author = {
Gascón, Jorge
 and
Bayona, José M.
 and
Espadero, José M.
 and
Otaduy, Miguel A.
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111134}
}
@inproceedings{
10.2312:pt.20111140,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Procedural Modeling of Suspension Bridges}},
author = {
Patow, Gustavo
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111140}
}
@inproceedings{
10.2312:pt.20111137,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
HaloDot: Visualization of the Relevance of Off-Screen Objects}},
author = {
Gonçalves, Tiago
 and
Afonso, Ana Paula
 and
Carmo, Maria Beatriz
 and
Pombinho, Paulo
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111137}
}
@inproceedings{
10.2312:pt.20111136,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Mobile Computational Photography: Exposure Fusion on the Nokia N900}},
author = {
Echevarria, Jose I.
 and
Gutierrez, Diego
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111136}
}
@inproceedings{
10.2312:pt.20111139,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
A Simple Surface Tracking Method for Physically-Based 3D Water Simulations}},
author = {
Amador, G.
 and
Gomes, A.
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111139}
}
@inproceedings{
10.2312:pt.20111138,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Inexpensive 3D Stereo for Two Users Using a Single Display}},
author = {
Re, Armando de la
 and
Martorell, Eduardo
 and
Camahort, Emilio
 and
Abad, Francisco
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111138}
}
@inproceedings{
10.2312:pt.20111143,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
GPU Collision Detection in Conformal Geometric Space}},
author = {
Roa, Eduardo
 and
Theoktisto, Víctor
 and
Fairén, Marta
 and
Navazo, Isabel
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111143}
}
@inproceedings{
10.2312:pt.20111142,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Procedural Modelling of Destructible Materials}},
author = {
Gestel, J. van
 and
Bidarra, R.
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111142}
}
@inproceedings{
10.2312:pt.20111144,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Parallel Collision Detection Oriented to Distributed Memory Architectures for High-Resolution Meshes}},
author = {
Novalbos, Marcos
 and
Sánchez, Alberto
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111144}
}
@inproceedings{
10.2312:pt.20111141,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Real-Time Modelling and Rendering of Sprayed Concrete}},
author = {
Vélez, G.
 and
Matey, L.
 and
Amundarain, A.
 and
Ordás, F.
 and
Marín, J.A.
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111141}
}
@inproceedings{
10.2312:pt.20111147,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Volume-Surface Collision Detection}},
author = {
Ortegano, J.
 and
Navarro, H.
 and
Carmona, R.
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111147}
}
@inproceedings{
10.2312:pt.20111148,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Augmented Reality for Web - A New Interaction Method Without Markers}},
author = {
Silva, Luis F. A.
 and
Silva, Frutuoso G. M.
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111148}
}
@inproceedings{
10.2312:pt.20111145,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Linear-Time Dynamics of Characters with Stiff Joints}},
author = {
Hernández, Fernando
 and
Garre, Carlos
 and
Casillas, Rubén
 and
Otaduy, Miguel A.
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111145}
}
@inproceedings{
10.2312:pt.20111146,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Interactive Elastic Deformation of 3D Images}},
author = {
Prados, Francisco J. R.
 and
Salas, Alejandro León
 and
Torres, Juan Carlos
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111146}
}
@inproceedings{
10.2312:pt.20111152,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Investigating the Differences Between European Portuguese Sounds: An Approach Using Polygonal Mesh Comparison}},
author = {
Martins, Paula
 and
Silva, Samuel
 and
Oliveira, Catarina
 and
Ferreira, Carlos
 and
Silva, Augusto
 and
Teixeira, António
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111152}
}
@inproceedings{
10.2312:pt.20111153,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Left-Ventricle Global and Regional Functional Analysis from MDCT Images}},
author = {
Silva, Samuel
 and
Santos, Beatriz Sousa
 and
Madeira, Joaquim
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111153}
}
@inproceedings{
10.2312:pt.20111151,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
A Moving Least Squares Method for Implant Model Deformation in Computer Aided Orthopedic Surgery for Fractures of Lower Extremities}},
author = {
Ramírez, Esmitt
 and
Coto, Ernesto
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111151}
}
@inproceedings{
10.2312:pt.20111149,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
Robust Method for Estimating Normals on Point Clouds Using Adaptive Neighborhood Size}},
author = {
Leal, E.A.
 and
Leal, N.E.
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111149}
}
@inproceedings{
10.2312:pt.20111150,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
3DWikiU - 3D Wiki For Urban Environments}},
author = {
Melo, M.
 and
Silva, P.
 and
Magalhães, L.
 and
Bessa, M.
 and
Coelho, A.
 and
Moura, J.
 and
Rocha, A.
 and
Ferreira, F.
 and
Cruz, J.
 and
Sousa, A.
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111150}
}
@inproceedings{
10.2312:pt.20111154,
booktitle = {
V Ibero-American Symposium in Computer Graphics},
editor = {
Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
}, title = {{
A Colour Rotation Based Detector for Bleeding Gastric Pathologies}},
author = {
Coelho, P.
 and
Cunha, A.
 and
Costa, P.
 and
Hadjileontiadis, L.
}, year = {
2021},
publisher = {
The Eurographics Association},
ISBN = {978-3-03868-152-6},
DOI = {
10.2312/pt.20111154}
}

Browse

Recent Submissions

Now showing 1 - 33 of 33
  • Item
    Proceedings Info
    (Eurographics Association, 2021-06-15) Silva, F.; Gutierrez, D.; Rodríguez, J.; Figueiredo, M.
  • Item
    Digital Cartographic Generalization in Spatial Databases: application issues in Power Grids CAD tools
    (The Eurographics Association, 2021) Rodríguez, Javier Novo; Pereira, Elena Hernández; Canosa, Mariano Cabrero; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    This work presents the results of applying several digital cartographic generalization techniques to improve the performance of an Electrical Power Grids Computer-Aided-Design application. The performance increase is attained by adjusting the level of detail of the grid topology being visualized in the CAD application. This adjustment takes place at the database level using a multi-scale architecture and the available spatial extensions of Geographic Information Systems databases. The data volume is minimized to fit the exact requirements of the scale being used in the visualization so that no processing time is wasted on representing irrelevant elements. Results show that up to a 90 % of the data can be skipped and thus, a 84 % of the time required to render the visualization can be saved on average, enabling the CAD application to render it in real-time. Furthermore, the optical legibility of the grid visualization is enhanced as a consequence of applying cartographic generalization.
  • Item
    3D Visualization of Sparse Geophysical Data Representing Uncertainty
    (The Eurographics Association, 2021) Gonçalves, Vítor; Dias, Paulo; Almeida, Fernando; Madeira, Joaquim; Santos, Beatriz Sousa; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Geophysical data are sparse and by nature difficult to analyze. Usually domain experts use "mental models" to infer missing data according to the surrounding data and their own knowledge. The main goal of this work is to explore the best way to represent uncertainty in geophysical data. Given the sparse nature of the represented data, it is important to provide a 3D volumetric representation of the whole subsoil, based on a geostatistical process. We use kriging interpolation to generate a structured grid from the original sparse data. However, the analysis of such an interpolated representation must be careful, since the uncertainty varies significantly according to the distance to real measurements. We use different representations to emphasize data uncertainty during the analysis stage. The different visualization techniques implemented in our prototype, as well as methods used to simultaneously visualize resistivity and uncertainty information, are presented.
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    Interactive Visualizations of Automatic Debugging Reports
    (The Eurographics Association, 2021) Riboira, André; Rodrigues, Rui; Abreu, Rui; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Automated debugging techniques, based on statistical analysis of historical test executions data, have recently received considerable attention due to their diagnostic capabilities. However, current automatic debugging tools suffer from a common shortcoming that may affect their adoption and correct use: the lack of effective visualizations of their output. This paper explores the use of interactive visualization techniques applied to automatic debugging results, and integrated in a common development environment (Eclipse), to improve the efficiency of the debugging process. The proposed tool – GZOLTAR– is an Eclipse plug-in that includes an automatic debugging algorithm and generates interactive visualizations of the resulting hierarchical data, with direct links to the IDE's source code editor.
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    GraphJudge: A System for Assisted Assessment of Computer Graphics Assignments
    (The Eurographics Association, 2021) Rocha, Lindomar; Rodrigues, Rui; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    We describe a system for submission, automated validation and assisted evaluation of Computer Graphics' assignments. This type of assessments has a series of specific challenges associated to it, namely the analysis of graphical output and the variations between implementation in different development platforms and operating systems. When considering a large number of submitted programs (in the order of hundreds), preparing and evaluating the submissions quickly becomes a very time-consuming task. The goals of the system are therefore to allow submission and early validation for the students, and to ease the teachers' burden of compiling and executing, while automatically providing visual information of the submissions in an integrated and effective way.
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    Neural Data Exploration with Force Feedback
    (The Eurographics Association, 2021) Raya, Laura; Otaduy, Miguel A.; García, Marcos; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    The behavior of the brain depends to a large extend on its neural structure. Therefore, understanding this neural topology is a high-priority research line for neurobiologists. Due to complexity of the brain's neural structure, visual representations look tangled, and extracting knowledge from them is a difficult task. In this work, we propose the use of multimodal interfaces to enhance neurobiologists' understanding of neural data. Our system is based on four pillars: a stereo rendering module, a camera control system, a visual aid unit, and a haptically constrained navigation tool. We observe that haptically aided navigation helps neurobiologists analyze the brain's topology. Our system uses stylus-based haptic devices with two purposes: they provide a natural interface to deal with 3D data (controlling camera motion) and they constrain the user's motion. The system was built trying to keep user interactions as intuitive as possible.
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    High-quality Compression of Mipmapped Textures
    (The Eurographics Association, 2021) Andujar, C.; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    High-quality texture minification techniques, including trilinear and anisotropic filtering, require texture data to be arranged into a collection of prefiltered texture maps called mipmaps. In this paper we present a compression scheme for mipmapped textures which achieves much higher quality than current native schemes by exploiting image coherence across mipmap levels. The basic idea is to use a high-quality native compressed format for the upper levels of the mipmap pyramid (to retain efficient minification filtering) together with a novel compact representation of the detail provided by the highest-resolution mipmap. Key elements of our approach include delta-encoding of the luminance signal, efficient encoding of coherent regions through texel runs following a Hilbert scan, a scheme for run encoding supporting fast random-access, and a predictive approach for encoding indices of variable-length blocks. We show that our scheme clearly outperforms native 6:1 compressed texture formats in terms of image quality while still providing real-time rendering of trilinearly-filtered textures.
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    Graph-Based Reflectance Segmentation
    (The Eurographics Association, 2021) Garces, Elena; Gutierrez, Diego; Lopez-Moreno, Jorge; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Most of the unsupervised image segmentation algorithms use just RGB color information in order to establish the similarity criteria between pixels in the image. This leads in many cases to a wrong interpretation of the scene since these criteria do not consider the physical interactions which give raise to of those RGB values (illumination, geometry, albedo) nor our perception of the scene. In this paper, we propose a novel criterion for unsupervised image segmentation which not only relies on color features, but also takes into account an approximation of the materials reflectance. By using a perceptually uniform color space, we apply our criterion to one of the most relevant state of the art segmentation techniques, showing its suitability for segmenting images into small and coherent clusters of constant reflectance. Furthermore, due to the wide adoption of such algorithm, we provide for the first time in the literature an evaluation of this technique under several scenarios and different configurations of its parameters. Finally, in order to enhance both the accuracy of the segmentation and the inner coherence of the clusters, we apply a series of image processing filters to the input image (median, mean-shift, bilateral), analyzing their effects in the segmentation process. Our results can be transferred to any image segmentation algorithm.
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    Non-Uniform Spherical Light Fields
    (The Eurographics Association, 2021) Blasco, J.; Abad, F.; Camahort, E.; Vivó, R.; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    The study of the light field, as a function defining the radiance along the different viewing directions of a scene, started more than a decade ago and is still ongoing due to its interesting applications. Among the different parameterizations existing for the light field, we will be centered on the spherical light-field parameterization due to its quality of viewpoint-independency. In this work, we present an improved multiresolution method for rendering of spherical light fields with a non-uniform sampling, while focusing on the visualization of large storage volume light-field datasets.
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    Interacting with Outdoor Sports Performance Data
    (The Eurographics Association, 2021) Lopes, J. M. Brisson; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    This paper presents a portable application to visualize performance data obtained from GPS devices in outdoor sports (e.g., ski, running, BTT) that also record data as heartbeat rate. GPS file formats are analyzed and a data structure that enables easy and flexible data manipulation is presented. Several data representation (chart, map and table) and visualization issues are addressed. Results show that the set of interaction design requirements was appropriate. The application is portable to due the development tools adopted (OpenGL, GLUI and TinyXML).
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    Coded Apertures for Defocus Deblurring
    (The Eurographics Association, 2021) Masia, Belen; Corrales, Adrian; Presa, Lara; Gutierrez, Diego; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    The field of computational photography, and in particular the design and implementation of coded apertures, has yielded impressive results in the last years. Among their applications lies defocus deblurring, in which we focus in this paper. Following the approach of previous works, we obtain near-optimal coded apertures using a genetic algorithm and an existing quality metric. We perform both synthetic and real experiments, testing the performance of the apertures along the dimensions of depth, size and shape. We additionally explore non-binary apertures, usually overlooked in the literature, and perform a comparative analysis with their binary counterparts.
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    Efficient Propagation of Light Field Edits
    (The Eurographics Association, 2021) Jarabo, Adrian; Masia, Belen; Gutierrez, Diego; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Light field editing is a complex task, due to the large amount of data and the need to keep consistency between views. This has hampered the creation of efficient edit propagation methods, similar to those existing for single images. We propose a framework to edit light fields at interactive rates, by propagating some sparse user edits in the full light field. This propagation is guided by a novel affinity function, which forces similar pixels (defined by our affinity space) to receive similar edits, thus ensuring consistency. To manage the light field's large amount of data, we propose a novel multi-dimensional downsampling technique: we first cluster pixels with high affinity, and then perform edit propagation over the downsampled data. We finally upsample back to the original full resolution, maintaining visual fidelity and view consistency between views.
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    Cortical 3D Face Recognition Framework
    (The Eurographics Association, 2021) Rodrigues, J.; Lam, R.; Buf, J. du; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Empirical studies concerning face recognition suggest that faces may be stored in memory by a few canonical representations. In cortical area V1 exist double-opponent colour blobs, also simple, complex and end-stopped cells which provide input for a multiscale line/edge representation, keypoints for dynamic routing and saliency maps for Focus-of-Attention. All these combined allow us to segregate faces. Events of different facial views are stored in memory and combined in order to identify the view and recognise the face including facial expression. In this paper we show that with five 2D views and their cortical representations it is possible to determine the left-right and frontal-lateral-profile views and to achieve view-invariant recognition of 3D faces.
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    BlenderCAVE: Easy VR Authoring for Multi-Screen Displays
    (The Eurographics Association, 2021) Gascón, Jorge; Bayona, José M.; Espadero, José M.; Otaduy, Miguel A.; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    BlenderCave is a framework for the fast creation of virtual reality applications for multi-screen display systems. It consists of a set of extensions to the open-source Blender Game Engine (BGE), leveraging the scene creation and real-time rendering capabilities of BGE, and augmenting them with easy-to-setup support for CAVE or Powerwall-type displays. The framework is implemented in a distributed manner, and it contains a virtual camera setup to control the display output, and a lightweight network communication protocol to manage events and synchronize the application state. We demonstrate that, with BlenderCAVE, 3D applications can easily be written in Blender and displayed on multi-screen displays.
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    Procedural Modeling of Suspension Bridges
    (The Eurographics Association, 2021) Patow, Gustavo; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    In this paper we introduce a method for designing a class of engineering structures, namely suspension bridges. These bridges are ubiquitous in the industrialized countries, often appearing in known city landscapes, yet they are complex enough that hand-based modeling is tedious and time consuming. We present a method that finds the right proportions for such a structure through an optimization method that tries to distribute the tower positions while maintaining cable width to be a finite number. By simultaneously optimizing the span and sag of the cables of a bridge, we optimize the geometry and soundness of the structure. We present the details of our technique together with examples illustrating its use, including comparisons with real structures.
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    HaloDot: Visualization of the Relevance of Off-Screen Objects
    (The Eurographics Association, 2021) Gonçalves, Tiago; Afonso, Ana Paula; Carmo, Maria Beatriz; Pombinho, Paulo; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    The increasing usage of maps on mobile devices reinforce the need to solve some visualization and usability issues that constraint the user's interaction with information visualization applications. When exploring map information on a small screen device, the points of interest are often located off -screen. Despite the existence of several techniques for the visualization of off-screen objects, most of them use representations to indicate the direction and/or the distance towards these objects but none of them represent their relevance. This paper describes the work in progress to achieve a visualization that provides clues about the relevance of off-screen objects.
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    Mobile Computational Photography: Exposure Fusion on the Nokia N900
    (The Eurographics Association, 2021) Echevarria, Jose I.; Gutierrez, Diego; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    This paper explores the Nokia N900 platform as a versatile playground for mobile computational photography. We present the implementation of a simple yet practical application to acquire high quality tone mapped HDR images, and a relatively straightforward white balance selection. We have built everything from scratch: from the capture of the bracketed sequence of images with different exposures, to the final tone mapping algorithm. Completed in less than one week, showcasing the flexibility and productivity of the platform, our experiments have encouraged us to continue exploring all the possibilities this kind of devices offer.
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    A Simple Surface Tracking Method for Physically-Based 3D Water Simulations
    (The Eurographics Association, 2021) Amador, G.; Gomes, A.; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Water simulation, and more generically fluid simulation, is an important research topic in computer graphics. In 3D Eulerian Navier-Stokes-based water simulations, surface tracking and rendering are two delicate problems. The existing solutions to these problems (i.e., implicit surfaces-based approaches, height-fields, ray-tracing), are either to computationally intensive for real-time scenarios, or present bulge water surfaces (i.e., blobby water surfaces). In this paper, we propose a novel tracking algorithm for rendering water surfaces. Instead of tracking the flow of water using either level sets or height-fields, each cell of an 3D grid density value is directly measured in order to determine if it is either water, air, or water-air contact surface. The information in each cell is later used for the water surface splat rendering, using OpenGL vertex buffer objects.
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    Inexpensive 3D Stereo for Two Users Using a Single Display
    (The Eurographics Association, 2021) Re, Armando de la; Martorell, Eduardo; Camahort, Emilio; Abad, Francisco; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Multiuser computer systems allow several users to collaborate on the same task. Medium sized displays, like workbenches or tabletops provide a shared view of the task and a set of input devices to interface with the system. Some of the existing installations also provide 3D stereoscopic viewing, often also shared by all the participants and therefore incorrect for all of them but one. In these cases a different stereoscopic view for each user is desirable. We implemented two hardware configurations that support independent stereo viewing for two users sharing a common display using a 120Hz monitor and a 120Hz projector. Our prototypes use off-the-shelf parts to create a functional, responsive and inexpensive two-user 3D stereo display system. We also apply our systems to a competitive game, where each user has a private stereoscopic view of the game table, and a two-user multimedia player, where each user can watch and hear a different video on the same display.
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    GPU Collision Detection in Conformal Geometric Space
    (The Eurographics Association, 2021) Roa, Eduardo; Theoktisto, Víctor; Fairén, Marta; Navazo, Isabel; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    We derive a conformal algebra treatment unifying all types of collisions among points, vectors, areas (defined by bivectors and trivectors) and 3D solid objects (defined by trivectors and quadvectors), based in a reformulation of collision queries from R3 to conformal R4,1 space. The algebraic formulation in this 5D space is then implemented in GPU to allow faster parallel computation queries. Results show expected orders of magnitude improvements computing collisions among known mesh models, allowing interactive rates without using optimizations and bounding volume hierarchies.
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    Procedural Modelling of Destructible Materials
    (The Eurographics Association, 2021) Gestel, J. van; Bidarra, R.; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Traditional content creation for computer games is a costly process. In particular, current techniques for authoring destructible behaviour are often limited to a single object basis. In this paper, we build on previous research results to develop a novel method for designing reusable destructible behaviour which can be applied in real-time to a variety of objects. To separate the destructible behaviour from particular objects, we introduce the concept of destructible materials: where the material of an object usually defines the way an object looks, a destructible material will determine how it breaks. Destructible materials provide a reusable definition and intuitive way of designing and tweaking destructible behaviour of objects in game development, which can then be applied in real-time.
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    Parallel Collision Detection Oriented to Distributed Memory Architectures for High-Resolution Meshes
    (The Eurographics Association, 2021) Novalbos, Marcos; Sánchez, Alberto; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Higher resolution meshes should be used in graphics applications to make them as realistic as they can. However, they imply a high computational. Several approaches have been built to solve collision detection, although most of them do not take into account this feature. This paper presents a scalable parallel algorithm for collision detection designed for working with high resolution meshes. The algorithm is based on distributed memory architectures taking advantage of their benefits and overcoming their drawbacks.
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    Real-Time Modelling and Rendering of Sprayed Concrete
    (The Eurographics Association, 2021) Vélez, G.; Matey, L.; Amundarain, A.; Ordás, F.; Marín, J.A.; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    This paper presents a new real-time method to model and render how sprayed concrete is spread on a surface. The method not only models and renders deposits sprayed from any angle, any distance and with any concrete flow, but it is also able to compute the amount of deposited volume taking into account the percentage of material that rebounds. The proposed method has been developed for a real-time training simulator for concrete spraying machinery, where most of the algorithm is parallelised and computed in the GPU, leaving the CPU free for other computations. In this research, the method has been validated for its use on plain surfaces and tunnel walls, but it can be extended to other types of surfaces.
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    Volume-Surface Collision Detection
    (The Eurographics Association, 2021) Ortegano, J.; Navarro, H.; Carmona, R.; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    The presence or not of collisions between objects is usually required to study the interaction between them, increasing the realism in virtual environments. Collision detection between polygonal objects has been widely studied, and more recently some studies have been made concerning collisions between volume objects. Collision detection between volume datasets and polygonal objects is introduced in this work. This kind of mixed scenes appears naturally in many applications such as surgery simulation and volume edition. To detect the collision, first the volume dataset is represented by a single 3D texture. Then, a mapping from eye space to volume space is established, such as each mesh fragment has a 3D texture coordinate. The collision is verified by fragment during the rasterization stage. We use OpenGL R occlusion query extension to count the number of mesh fragments colliding with the volume. Our tests show that up to 3800 pairs of volume-mesh may be evaluated in one second.
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    Augmented Reality for Web - A New Interaction Method Without Markers
    (The Eurographics Association, 2021) Silva, Luis F. A.; Silva, Frutuoso G. M.; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    In the new age of omnipresent internet, browsers are accessible on every device in everyday's life. Thus it is also needed new interaction methods to facilitate the interaction through browser. Augmented reality is one of the techniques that is available now via browser. In this paper we present a new method of interaction without physical markers for augmented reality via browser. The first part of the paper describes the use of augmented reality via browser using physical markers and its limitations. In the second part, we propose a solution to solve the limitations of augmented reality using physical markers, i.e. we propose a new interaction method to manipulate virtual objects without using physical markers. Finally, we show a simple augmented web game based on the new interaction method proposed.
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    Linear-Time Dynamics of Characters with Stiff Joints
    (The Eurographics Association, 2021) Hernández, Fernando; Garre, Carlos; Casillas, Rubén; Otaduy, Miguel A.; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Characters, like other articulated objects and structures, are typically simulated using articulated dynamics algorithms. There are efficient linear-time algorithms for the simulation of open-chain articulated bodies, but complexity grows notably under additional constraints such as joint limits, loops or contact, or if the bodies undergo stiff joint forces. This paper presents a linear-time algorithm for the simulation of open-chain articulated bodies with joint limits and stiff joint forces. This novel algorithm uses implicit integration to simulate stiff forces in a stable manner, and avoids drift by formulating joint constraints implicitly. One additional interesting feature of the algorithm is that its practical implementation entails only small modifications to a popular algorithm.
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    Interactive Elastic Deformation of 3D Images
    (The Eurographics Association, 2021) Prados, Francisco J. R.; Salas, Alejandro León; Torres, Juan Carlos; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    The standard workflow of a haptic device takes the position of the effector in space and sends a force vector in return. This paradigm naturally meets the behaviour shown in elastic materials, where the resistant force of a body is proportional to the displacements created. In fact many works have designed methods to simulate interaction with linear-elastic bodies, covering different techniques from spring-mass structures to specific volumetric representations. However, realistic simulation of volumetric data is still an open issue. Not only is it challenging due to the complex relations that govern the real elastic behaviour, but also because of the huge amount of data that needs to be processed. In this paper we propose a technique to interactively deform 3D images, such as those acquired by a CT scanner. While producing a physically plausible haptic feedback, deformation and visualization algorithms produce an efficient and natural feeling. Using a free form deformation structure as a wrapper, it is possible to deform complex structures at high frame rates, independently of the size of the volume.
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    Investigating the Differences Between European Portuguese Sounds: An Approach Using Polygonal Mesh Comparison
    (The Eurographics Association, 2021) Martins, Paula; Silva, Samuel; Oliveira, Catarina; Ferreira, Carlos; Silva, Augusto; Teixeira, António; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    With the main purpose of studying the articulatory configuration of the European Portuguese (EP) sounds and to evaluate coarticulatory effects, a large 3D MRI database from several speakers and contexts have been acquired. Segmentation, visualization and interpretation of all the available data, essential to a detailed characterization of these sounds, are complex and time-consuming tasks. To perform the segmentation, a semi-automatic method was used. Meshes of the tongue were created from the segmented volumes and a polygonal mesh comparison tool (PolyMeCo) was used to compare: different sounds, the same sound produced in different contexts and syllabic positions, and productions from different speakers, providing a qualitative measure of these differences. To the best of our knowledge this is the first study in the literature using such an approach to analyze and compare tongue shape. Furthermore, these first results are very promising allowing a proper analysis and depiction of the main differences between EP sounds and further insight into their production.
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    Left-Ventricle Global and Regional Functional Analysis from MDCT Images
    (The Eurographics Association, 2021) Silva, Samuel; Santos, Beatriz Sousa; Madeira, Joaquim; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Left-ventricle functional analysis is of paramount importance for the assessment of coronary artery disease. Non-invasive coronary artery imaging using multiple-detector computed tomography (MDCT) provides a wealth of data concerning multiple cardiac phases. These have still to be explored in order to assess if further insight is possible regarding regional and functional analysis of the left ventricle leading to a more informed diagnosis and prognosis. Following on previous work regarding left-ventricle segmentation of all available cardiac phases in MDCT exams this article presents several parameters characterizing global and regional left ventricle function, computed for several cardiac phases and represented over time. Synchronized viewing of the different parameters is also supported.
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    A Moving Least Squares Method for Implant Model Deformation in Computer Aided Orthopedic Surgery for Fractures of Lower Extremities
    (The Eurographics Association, 2021) Ramírez, Esmitt; Coto, Ernesto; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Preoperative planning is an essential step before performing any surgical procedure. Computer Aided Orthopedic Surgery (CAOS) systems are extensively used for the planning of surgeries for fractures of lower extremities. These systems are input an X-Ray image and the planning can be digitally overlaid onto the image. The planning includes reassembling the fractured bone and possibly adding implants to reduce the fracture. In many cases, the implant does not fit perfectly in the patient's anatomy and it must be bended to adjust the implant to the bone. This paper presents a new method for the deformation of implants in CAOS systems, based on the Moving Least Squares (MLS) method for 2D images. Several improvements over the original MLS method are introduced to achieve visual results similar to the real procedure and make the deformation process easier and simpler for the surgeon. The improvements are explained in detail and all parameter values are provided. Over 100 clinical surgeries have been already planned successfully using a CAOS system that employs the proposed technique.
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    Robust Method for Estimating Normals on Point Clouds Using Adaptive Neighborhood Size
    (The Eurographics Association, 2021) Leal, E.A.; Leal, N.E.; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Normal estimation on sampled curves or surfaces is a basic step of many algorithms in computer graphics, computer vision, and especially in recognition and reconstruction of three dimensional objects. This paper presents a simple and intuitive method for estimating normals on point based surfaces. The method is based on Robust Principal Component Analysis (RPCA) therefore is capable to deal with noisy data and outliers. In order to estimate an accurate normal on a point, our method takes a neighborhood of variable size around the point. The neighborhood size depends on local properties of the sampled surface. It is shown that the estimation of the tangent plane on a point is more accurate using a neighborhood of variable size than using a fixed one.
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    3DWikiU - 3D Wiki For Urban Environments
    (The Eurographics Association, 2021) Melo, M.; Silva, P.; Magalhães, L.; Bessa, M.; Coelho, A.; Moura, J.; Rocha, A.; Ferreira, F.; Cruz, J.; Sousa, A.; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Virtual Reality (VR) systems may be used with great effectiveness in applications such as urban planning, virtual tourism, cultural heritage and education. In fact, the VR systems allow the visualization and interaction with 3D models, which can work as a natural metaphor due to their similarities with the objects that they intend to recreate. This is the perfect scenario for this project which intends to recreate virtual urban environments and complement them with digital services useful for people's everyday tasks. On the other hand, the implementation and management of a virtual environment is complex and requires a numerous development team with different skills to build it properly. The purpose of this project is to build a collaborative environment where the users have the power to contribute and edit objects in the referred environment, exploring the wiki concept. This paper presents a collaborative VR system that aims to provide a more natural and intuitive interface to access diversified services on 3D urban environments - 3D Wiki for urban environments. These services shall contemplate citizenship activities, entrepreneurship activities, promotion of the natural and cultural heritage and support of the cooperation and data sharing among citizens.
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    A Colour Rotation Based Detector for Bleeding Gastric Pathologies
    (The Eurographics Association, 2021) Coelho, P.; Cunha, A.; Costa, P.; Hadjileontiadis, L.; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.
    Colour is one the distinct features in computer vision systems and can be represented in several colour spaces. The most commonly used is the RGB colour space, since most high-quality cameras used in computer vision systems provide RGB signals, for example endoscopic capsule cameras. This work describes a computer vision algorithm intended to assist the physician in the diagnosis of endoscopic diseases, such as gastrointestinal bleeding, using a colour space rotation-based method. This algorithm modifies the images RGB representation channels in such way that the bleeding information can be effectively enhanced in a single channel. Tests in endoscopic images were performed and results have shown that the proposed colour-based rotation approach successfully increases the detection of bleeding regions in endoscopic images, corroborating the usefulness in physician diagnosis assistance.