Alex Laier Web Spot

Computer Graphics, Geometry, Seismic Processing, Reconstruction, Compression

 
Medial axis based on level set

Description: An implementation level set made to the cg course of Geovan Tavares 
Download src: geostat.7z

 
Scale-Space for Union of 3D Balls

Scale-Space for Union of 3D Balls

Sibgrapi 2009

Abstract—Shape discretization through union of weighted points or balls appears as a common representation in different fields of computer graphics and geometric modeling. Among others, it has been very successful for implicit surface reconstruction with radial basis functions, molecular atomic models, fluid simulation from particle systems and deformation tracking with particle filters. These representations are commonly generated from real measurements or numerical computations, which may require filtering and smoothing operations. This work proposes a smoothing mechanism for union of balls that tries to inherit from the scale-space properties of bi-dimensional curvature motion: it avoids disconnecting the shape, prevents self-intersection, regularly decreases the area and convexifies the shape. The smoothing is computed iteratively by moving each ball of the union according to a combination of projected planar curvature motions. Experiments exhibits nice properties of this scale-space.
Keywords-Union of Balls; Scale Spaces; Curvature Motion;
 
Gsl 1.11 port Microsoft Visual Studio 2008 vc9.0


Description: A port of the gsl - Gnu scientifc library - to Microsoft Visual Studio 2008 compiler. This is a port of GSL 1.11 to Microsoft Visual C++ 2008 (vc 9.0)

I maintain this port because I had problems with the debug informations of the cygwin binaries distribution.

Contact me if you need the library in other forms (at the moment, only static library with static runtime is provided)

The release version have sse2 enabled.

Settings you have to change when creating your own project :

- additional include directory should point to win32\gsl\include
- additional library directory should point to win32\gsl\lib\debug_static-vc90 or win32\gsl\lib\release_static-vc90
- Code generation : use /MTd for Debug and /MT for Release (static c runtime)
- Debug config should link with "cblas.lib gsl.lib"
- Release config should link with "cblas.lib gsl.lib"

The binary distribution contains an example project to show how to se this library with Microsoft Visual C++ 2008 (vc 9.0). Just load win32\example\example.sln into visual studio, compile and run.

This version is based on the work on port of  David Geldreich ( This e-mail address is being protected from spambots. You need JavaScript enabled to view it )
Visual Studio 2003.net port Latest version could be found on : http://david.geldreich.free.fr/dev.html

Autor: Alex Laier Bordignon ( This e-mail address is being protected from spambots. You need JavaScript enabled to view it http://matmidia.org/alexlaier
Date: 4/28/2009

Source code and binaries: Download (4,4 MB)

Source code only: Download (1,7 MB)

 
Point set compression through BSP quantization

Point set compression through BSP quantization

Sibgrapi 2006 - Brazilian Symposium on Computer Graphics and Image Processing 2006
    
 
This work introduces a new compression scheme for point sets. This scheme relies on an adaptive binary space partition (BSP) which takes into account the geometric structure of the point set. This choice introduces geometrical rather than combinatorial information in the compression scheme. In order to effectively improve the final compression ratio, this partition is encoded in a progressive manner, decreasing the number of bits used for the quantisation at each subdivision. This strategy distributes the extra cost of the geometry encoding onto the maximal number of points, compressing in average 15% more than previous techniques.
 
Approximations by smooth transitions in binary space partitions

 

Approximations by smooth transitions in binary space partitions

Sibgrapi 2008 - Brazilian Symposium on Computer Graphics and Image Processing 2008
  

   
This work proposes a simple approximation scheme for discrete data that leads to an infinitely smooth result without global optimization. It combines the flexibility of Binary Space Partitions Trees with the statistical robustness of Smooth Transition Regression Trees. The construction of the tree is straightforward and easily controllable, using error-driven metrics or external constraints. Moreover, it leads to a concise representation. Applications on synthetic and real data, both scalar and vector-valued demonstrated the effectiveness of this approach.
 

 

 

Colaborators

Betina Vath - UFF
Geovan Tavares - PUC-Rio
Hélio Lopes - PUC-Rio
Thomas Lewiner - PUC-Rio
João Xavier - Harvard
Welles Morgado - PUC-Rio
Lucas Sigbaund - PUC-Rio
Sinésio Pesco - PUC-Rio
Kevin Foster - Harvard
Rogério Santos - Petrobras
Marcos Lage - PUC-Rio
Luciano Reis - Petrobras
Luiz Velho - IMPA
Rener Castro - PUC-Rio
Thales Vieira - PUC-Rio
Fabiano Petroneto - PUC-Rio
Afonso Paiva Neto - PUC-Rio
Doherty Andrade - UEM
Valdeni Soliani Franco - UEM
João Geronimo - UEM
André Timoteo Menes - PUC-Rio
Renata Thomaz - Puc-Rio / Ufal
João Paixão - Puc-Rio