Previous Projects on Computer Graphics, Visualization and Interaction

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Bifocal tree visualization technique (Cava, 2002): Using a focus + context approach to explore hierarchical information spaces


Information Visualization Conceptual Framework, Techniques and Applications

Project Description:

Information visualization is a quite new area that relies on perception and design concepts, human-computer interaction aspects and computer graphics techniques to produce visual representations of data. Usually these data do not have an intrinsic geometry like the objects we are used to in conventional computer graphics applications. The goal is to let a user to explore, search and browse the data space until insight from the data is achieved. The project investigates fundamental concepts and techniques for information visualization and aims both at developing new techniques for different applications as well as to determine a set of criteria for the usability evaluation of this class of tools. The project was supported by CNPq and FAPERGS, and involved activities also sponsored by CAPES/COFECUB as part of the SPIDER project.

Research Activities:

This research relied on a series of activities developed mainly as MSc dissertations or PhD theses, which are summarized below:

  • Bifocal Browser: a technique for the interactive visualization of hierarchies, which was developed by Ricardo Cava as his Master dissertation.
  • Evalution criteria to analyze and compare techniques for the visualization of hierarchical information: this investigation was centered at Paulo R.G. Luzzardi's PhD thesis.
  • Graph visualization as a mean to display hyperautomaton-based documents: Daniela Saito studyied techniques to exhibit graphs (with fish-eye effects) motivated by applications of web-based courses that model electronic books as finite automaton with output.
  • Visualization of geo-referenced biological data: in a previous work, Luiz Fernando Estivalet developed IconVis, a tool for the iconic visualization of data associated to populations of some species of small mammals. This work aims at developing a more generic tool that takes data from common data bases, and let a user to specify in a simple language the visual representations that should be used to represent each element in a sample.
  • Visualization of multidimensional data: as a follow-up work of Luzzardi's thesis and the project about geo-referenced data, Eliane Valiati studyed techniques for visualizing multi-dimensional data and investigated specific criteria for evaluating this kind of technique in her PhD thesis.
  • Scenario for evaluating visualization techniques: evaluating visualization techniques requires a planning experiments or test situations even though we are employing heuristic evaluation. Eliane Diniz worked in the definition of scenarios for evaluating hierarchical visualization techniques.

Responsible: Carla Maria Dal Sasso Freitas


Visualization and interaction with Virtual Patients

Credits: Silva (2001), Manssour (2002), Maciel (2002) and Villamil (2009)

Project Description:

The project had the goal of developing a representation of a virtual human in order to allow both visualization and navigation inside the structures as well as minimally-invasive surgery simulation and training. Another goal was movement simulation as a result of muscle deformation and simulation. The body representation should be built from structures modeled interactively or reconstructed from medical images. Concerning to skeloton modeling, correct positioning of joints are a very difficult task. On the other hand, medical images data sets (as the Visible Human project, for example) provide a huge amount of data that can be used both to direct visualization and geometric models reconstruction. The project was supported by CNPq and FAPERGS, and had straight connection with the LIVER-3D project.

Research Activities:

This project encompassed the definition of a framework integrating a hierarchy of classes which were developed in the following sub-projects:

  • Modelling of the temporo-mandibular joint, by Marta Becker Villamil (2009).
  • Evaluation of the quality of volume rendered images, by Isabel Siqueira da Silva (2003)
  • Virtual-reality based tool for endoscopic surgery training, by Julierme Kruger Gavião (2003).
  • Multi-modal volume visualization, by Isabel Harb Manssour (2002).
  • Anatomically based modelling of skeletons and simulation of muscles actions and deformations, by Luciana Porcher Nedel (while pos-doc researcher from 1998-2001)
  • Articulated body modeling with anatomically-based simulation of joints, by Anderson Maciel (2001)
  • Ray-casting based interactive volume visualization (RenderVox), by Marcelo Rodrigo M. Silva (2000)
  • Iso-surface extraction from volume data using the marching cubes technique by Eduardo Kenzo (undergraduate student, 1999

See also the LIVER-3D project description, which dealed with a specific problem regarding modelling parts of the human body for exploration.

Responsibles: Carla Maria Dal Sasso Freitas, Luciana Porcher Nedel

Virtual liver volumetric model (Dietrich, 2004)
3D sculpting tools for interacting with volumetric models (Huff et al., 2007)


Visualization and interaction with Virtual Liver

Project Description:

The project had the goal of developing a virtual representation of a human liver in order to allow visualization, exploration and measurements for transplant planning. The project was supported by CNPq, and the team was also composed by physicians and physicists who validated the visualization and measurement techniques.

Research Activities:

This project was based on the use of hardware assisted volumetric visualization and besides the development of the techniques, there was a validation phase with potential users. The activities were mainly based on Carlos Dietrich's MSc dissertation under the advisory of Luciana Nedel and Silvia Olabarriaga. Later on, two other students developed their work within this project. Rafael Huff developed sculpting tools to explore the volumes, and conducted a series of experiments validating the interactive techniques using 2D and 3D devices as well as one and two-handed interaction. Roberto Silveira da Rosa Jr. extended Huff's work by implementating fiiling tools to allow interacting with volume data with the objective of adding material. This was motivated by the need of easily building bio models to be employed as prosthesis.

Responsible: Luciana Porcher Nedel.

Researchers: Carla Maria Dal Sasso Freitas, Silvia Olabarriaga and João Comba.

Experiments with 3D selection techniques (Jacon-Jacob et al., 2003): comparing user performance with different techniques in a virtual chess application

3D Interaction with Virtual Devices

Project Description:

Navigation, object selection and manipulation in virtual environments are based on interaction methods or techniques driven by conventional or special devices. There are a number of techniques and devices available for the development of applications involving interaction in immersive worlds, and to choose the most suitable one for a given situation is a difficult task.

Research Activities:

This project was based on the development of interaction techniques using virtual reality devices as well as their evaluation. We also worked on the description of these techniques using formal models, as part of project SPIDER's activities. The following activities were accomplished:

  • Evaluation of manipulation and navigation techniques using data gloves, 3D glasses and head mounted displays: Liliane Jacob's MSc dissertation.
  • Simultaneous manipulation of 3D virtual objects: Marcio Pinho's PhD thesis.
  • Using virtual laparoscopic interface in a prototype for medical training: Julierme Gavião's MSc dissertation.

Responsibles: Carla MDS Freitas and Luciana Nedel

Bifocal tree application (Winckler et al., 2004): Using the Bifocal tree technique for visualizing web site models


Specification and Prototyping for User Interface Design, Engineering and Re-engineering for the Web Models, Formalisms, Techniques and Tools for Designing, Evaluating and Visualizing Web Interfaces

Project Description:

The project was sponsored by CAPES/COFECUB and joined the activities of VisCA brazilian project (see above description) and LIIHS projects on these subjects.

See Spider Web Description [1] by Marco Winkler.

Responsibles: Carla Maria Dal Sasso Freitas and Marcelo Pimenta; Phillipe Palanque (LIIHS - IRIT, Toulouse, France)

MAPEM (Binotto et al., 2003): Visualizing the simulation of cuttings discharge in a deep-water oil well drilling process


Environmental Monitoring of Deep Sea Drilling for Petroleum Exploration

Project Description:

MAPEM was a collaboration project jointly developed by several groups. The Institute of Geosciences proposed the project for establishing a methodology for environment monitoring of drilling activities and their impact on biodiversity. The collaborating institutions were the Chemistry Department, Statistical Department and the Computer Science Institute (specifically, our group), from UFRGS, and the Marine Fauna Study group from UFSC.

Research Activities:

Our goal in this project was to model and simulate the distribution of cuttings and mud discharged by drilling activities. Conventional countour plots were generated from data output by the simulation. The main contribution regarding original reseach results were due to the 3D dynamic visualization of discharge.

Project coordination: Elirio Toldo (Geosciences Institute, UFRGS)

Modeling, simulation and visualization group: Carla MDS Freitas (group coordination), João LD Comba; MSc. Maria Pivel, Alecio Binotto, Carla D'Aquino e Silvia Coan.

Geovis(Karen Basso, 1999): Visualization of a geological layer with an associated scalar attribute mapped to colors


Visualization in Scientific Computing Environment

Project Description:

Scientific Visualization consists of a set of techniques developed to support the analysis of scientific data. These data can come from samples collected through various measurement instruments like satellites, medical equipments, radars, etc, can be produced by analysis or simulation processes, or can be simply gathered by human observation. Samples can be data values or images which often must go under some processing before being analysed. Computer Graphics techniques are widely used in generating visual representations of such data. The aim of this project was to build interactive tools to support the analysis of scientific data. There were many research activities associated with this project, dealing with data coming from a variety of sources: medical data, oil prospecting data, meteorological and biological data. The project was supported by CNPq, Brazil.

Research Activities:

Two main research activities were under this project:

  • Development of a set of interactive visualization tools named GeoVis, for the analysis of oil prospecting data, specially, geological samples from prospecting wells. The project started with the Master thesis of Karen Basso, who worked with us until 1999 as a research assistant). Mauricio Drehmer and Rodrigo Resmini Zanella also participated in this project as undergraduate research assistants.
  • Development of a meteorological application named Pythonisa. Carlos A. Moreira dos Santos developed a system based on a visual language intended to aid meteorologists in their task of elaborating weather forecasting, using the outputs of meteorological models and other sources of data. Carlos aimed at extending Vis-5D for this, and Alfredo Kojima was a collaborator in this project.

Responsible: Carla Maria Dal Sasso Freitas

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