I have a broad research interest that encompasses various aspects of
computer graphics and related areas.
Nonetheless, the central focus of my work has been the investigation of
multiscale models and hierarchical computational methods
associated with them.
Below, I summarize my research activity in the following topics:
Download: electronic versions of all papers cited here are available from my
Research in applications of deep learning to Graphics and Image Processing.
- Daniel Ferreira Moreira, Cristina Nader Vasconcelos, Aline Paes, and
Luiz Velho. "Deep Image Classification of a Wild Data Set for Olympic
Sport". In Proceedings of Workpedia, 2016.
- Luiz Velho and Julia Giannella. "OBSERVATOR!O2016 - Experiencias em
Deep Learning". Book, VISGRAF Lab - IMPA, 2016.
Big Data and Visualization
Research in Analysis and Visualization of Large Multimedia Datasets.
Papers and Reports:
Julia Giannella and Luiz Velho. "OBSERVATOR!O2016". Technical Report TR-08-2016, Laboratorio VISGRAF - IMPA, 2016.
Research in new methods for Mixed Reality.
- Aldo Zang and Luiz Velho. "Panoramas RGBD Omnidirecionais com Multiplas Camadas e suas Aplicacoes". In Proceedings of SIBGRAPI Workshop of Works in Progress, 201
Moebius Transformations for Omnidirectional Images
Research in applications of Moebius Transformations for 360 panoramic images.
- Luis Penaranda, Luiz Velho, and Leonardo Sacht. "Real-time Correction of Panoramic Images using Hyperbolic Moebius Transformations". Journal of Real-Time Image Processing, 2015.
RGBD and Applications
Research work on RGBD images and applications in the areas of modeling, vision, animation and interfaces.
- Djalma Lucio, Leandro Cruz, and Luiz Velho. "RGBD Camera Effects". In Proceedings of SIBGRAPI Workshop on Interactive Visualization, 2012
- Fabian Prada, Leandro Cruz, and Luiz Velho. "Object Extraction in RGBD Images". In Proceedings of SIBGRAPI Workshop of Works in Progress, 2012.
- David Pires, Roberto Marcondes, and Luiz Velho. "Segmentaca de movimento a partir de imagens RGBD usando homomorfismo entre grafos". In VI Simposio de Iniciacao Cientifica e Pos-Graduacao do IME, 2012.
Research on the use of modern GPU architectures for simulation, modeling and visualization.
- Leonardo Carvalho, Maria Andrade, and Luiz Velho. "Fluid Simulation on Surfaces in the GPU". In Proceedings of XXV SIBGRAPI - Conference on Graphics, Patterns and Images, 2012.
- Andre Maximo and Luiz Velho. "M4G: Manifolds for GPUs Library". In Proceedings of Minisymposium on Publicly Available Geometric/Topological Software, 2012.
Mobile Visual Computing
Investigation of various aspects of Mobile Visual Computing, including: image processing for computational photography and video; interactive graphics and augmented reality
- Alexandre Chapiro, Marcelo Cicconet, and Luiz Velho. "Filter Based Deghosting for Exposure Fusion Video". In SIGGRAPH Technical Sketches and Posters, 2011.
Tassio Knop de Castro, Alexandre Chapiro, Marcelo Cicconet, and Luiz Velho. "Mobile HDR Video". In Eurographics - HDRI Area Papers, 2011.
Development of new platforms and software for Augmented Reality.
- Aldo Zang and Luiz Velho. "Um framework para renderizacoes foto-realistas de cenas com realidade aumentada". In Proceedings of XXXVII Conferencia Lationamericana de Informática, 2011.
- Julio Lucio Martin and Luiz Velho. "A Platform for Spatial Augmented Reality". In Proceedings of VII Workshop de Realidade Virtual e Aumentada, 2010.
Work on techniques for acquisition and visualization of 3D stereo images and Phantograms.
- Bruno Madeira and Luiz Velho. "Uma plataforma para visualizacao estereoscopica horizontal". In Proceedings of VII Workshop de Realidade Virtual e Aumentada, 2010.
Research on methods for Sketch-Based Modeling and Rendering.
- Afonso Paiva, Ronan Amorim, Luiz Velho, and Mario Costa Sousa. "Sketch-Based Adaptive Mesh Augmentation using Stellar Operators". In Proceedings of SIBGRAPI, 2011.
- Leonardo Carvalho and Luiz Velho. "Generating sketch based adaptive meshes". In Proceedings of WGARI, 2011.
- Thiago Pereira, Emilio Vital Brazil, Ives Macedo, Mario Costa Sousa, Luiz Henrique de Figueiredo, and Luiz Velho. "RGBN sketch-based image warping". Graphical Models, 2010.
Work on several aspects of music synthesis, authoring and interaction.
Marcelo Cicconet, Ilana Paterman, Paulo Carvalho, and Luiz Velho. "The Blues Machine". In SIGGRAPH 2009 Conference Abstract and Applications.
Sergio Krakowski, Luiz Velho, and Francois Pachet. "Pandeiro Funk: Experiments on Rhythm-Based Interaction". In SIGGRAPH 2009 Conference Abstract and Applications.
Research on Modeling and Visualization of Surface Mesostructure using Normal Fields.
Thiago Pereira and Luiz Velho. "RGBN image editing". Editor IEEE Press, Proceedings of SIBGRAPI - XX Brazilian Symposium on Computer Graphics and Image Processing.
Thiago Pereira and Luiz Velho. "Normal Synthesis on RGBN Images". In Proceedings of GRAPP - International Conference on Computer Graphics Theory and Applications.
Investigation of Methods and Techniques for Processing and Authoring Gigapixel Panoramic Images.
Luiz Velho. "Panosuite: a Production Pipeline for Panoramas". In IEEE International Conference on Computational Photography.
Luiz Velho. "N-PAN: Narratives with Gigapixel Panoramas". In IEEE International Conference on Computational Photography,
Recent research on Compressive Sensing and its applications to Graphics and Vision
Adriana Schulz, Luiz Velho, and Eduardo A. B. da Silva,
"On the Empirical Rate-Distortion Performance of Compressive Sensing",
IEEE International Conference on Image Processing (ICIP), November 2009.
Surface Spectral Analysis
I am researching spectral methods for the analysis of discrete surfaces
that are represented by meshes with collaborators from Unicamp.
- Fernando de Goes, Siome Goldenstein and Luiz Velho.
"A Hierarchical Segmentation of Articulated Bodies".
Computer Graphics Forum, 2008.
I am developing a multidisciplinary project for Interactive Digital Art and Contemporary Dance
with choreographer Analivia Cordeiro.
- Alice Bodanzky, Silvia Steinberg, Analivia Cordeiro, Julio Lucio, Ilana Paterman, and Luiz Velho. "Choreographisms". In SIGGRAPH 2008 Conference Abstract and Applications, 2008.
- Luiz Velho, Julio Martins, Alice Bodanzky, Ilana Paterman, and Analivia Cordeiro. "Expressive Trajectories". In Proceedings of CAe 2008 - International Symposium on Computational Aesthetics in Graphics, Visualization, and Imaging, 2008.
I am studying different aspects of Facial Modeling and Animation with collaborators from
USP and USBC.
- Jesus Mena-Chalco, Ives Macedo, Roberto Marcondes Junior, and Luiz Velho. "PCA-based 3D Face Photography". In Proceedings of SIBGRAPI, 2008.
- Y. Chang, M. Vieira, M. Turk, and L. Velho. "Automatic 3D Facial Expression Analysis in Videos.". In Proceedings of IEEE International Workshop on Analysis and Modeling of Faces and Gestures, 2005.
- Ives Macedo, Emilio Vital Brazil, and Luiz Velho. "Expression Transfer between Photographs through Multilinear AAMs". In Proceedings of SIBGRAPI, 2006
I have been applying fluid simulation techniques to create
special effects on images.
L. G. Nonato, M. A. Batista, L. Velho, and C. Barcelos. "Shallow-Water Simulation in Digital Images". In Mathematical Methods in Image Processing - AMS/SBM Joint International Meeting, 2008.
Dalia Bonilla, Luis Gustavo Nonato, Andre Nachbin, and Luiz Velho. "Fluid Warping". In Proceedings of WTDCGPI. SBC, 2008.
Recent work with my Ph.D. student Esdras Medeiros and collaborators from PUC-Rio
investigates topological multiresolution of n-dimensional solid objects.
Esdras Medeiros, Thomas Lewiner, Helio Lopes, and Luiz Velho. "An Aspect Ratio Upper Bound in 2D Solid Alpha Complexes of Poisson Disc Samplings". Technical Report 02-07, IMPA - VISGRAF Laboratory, 2007.
Esdras Medeiros, Thomas Lewiner, Helio Lopes, and Luiz Velho. "Reconstructing Poisson Disc Samplings of Solid Objects with Topological Guarantees". Technical Report 03-07, IMPA - VISGRAF Laboratory, 2007.
Projective Atlas Representation
I am developing a representation for surfaces using projective atlas structure.
Luiz Velho and Jonas Sossai. "Projective Texture Atlas and Applications", chapter 1. Curves and Surfaces, Avignon. Nashboro Press, 2007.
Luiz Velho and Jonas Sossai. "Projective Texture Atlas Construction for 3D Photography". The Visual Computer, 23, 2007.
High Dynamic Range Imaging
I have been investigating applications and algorithms for High Dynamic Range Imaging.
Aldo Zang and Luiz Velho. "Sistema Composto para Amostragem e Geracao de Luzes a partir de Mapas de Iluminacao". In Proceedings of WTDCGPI. SBC, 2008.
Luiz Velho. "Histogram-Based HDR Video". In SIGGRAPH 2007 Conference Abstract and Applications. ACM SIGGRAPH, ACM Press, 2007.
Asla Sa, Luiz Velho, and Paulo Carvalho. "Simulating Film Response Curves from a Pair of LDR Images". In Proceedings of Symposium on Computational Photography and Video, 2005.
I have also written a book on HDR.
Fourth Generation Video
My interest in developing advanced vison applications led to the research of
a new paradigm for real-time scene capture and analysis.
Marcelo Vieira, Luiz Velho, Asla Sa, and Paulo Carvalho.
"Real-Time 3D Video".
In Visual Procedings of SIGGRAPH. ACM, 2004.
Marcelo Vieira, Asla Sa Luiz Velho, and Paulo Cezar Carvalho.
"A Camera-Projector System for Real-Time 3D Video".
In Proceeedings of PROCAMS 2005.
Roberto Cesar Jr., David Pires, Marcelo Vieira, and Luiz Velho.
"Tracking and Matching Connected Components from 3D Video".
In Proceedings of SIBGRAPI 2005.
Ya Chang, Marcelo Vieira, Matthew Turk, and Luiz Velho.
"Automatic 3D Facial Expression Analysis in Videos.".
In Proceedings of Workshop on Analysis and Modeling of Faces and Gestures, 2005
Recently, I have conducted research on shape and property acquisition for 3D photography.
The main results are on structured ligh coding.
Boris Mederos, Marcos Lage, Sueni Arouca, Fabiano Petronetto, Luiz Velho, Thomas Lewiner, and Helio Lopes. "Regularized Implicit Surface Reconstruction from Points and Normals". Journal of the Brazilian Computer Society, 2007.
Anselmo Montenegro, Paulo Carvalho, Jonas Sossai, and Luiz Velho. "Reconstruction of 3D object meshes from silhouette images". Journal of Mathematical Imaging and Vision, 2007.
Asla Medeiros e Sa, Esdras Soares de Medeiros Filho, Paulo Cezar Carvalho, and Luiz Velho.
"Coded Structured Light for 3D-Photography: an Overview".
RITA - Revista de Informatica Teorica e Aplicada, 2002.
Asla Sa and Luiz Velho Paulo Cezar Carvalho.
"Recovering Registered Geometry and High Dynamic Range Texture with Coded Structured Light".
In Proceedings of The 11th International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision, 2003.
Asla Sa, Paulo Cezar Carvalho, and Luiz Velho.
"(b, s)-BCSL : Structured Light Color Boundary Coding for 3D Photography".
In Proceedings of 7th International Fall Workshop on VISION, MODELING, AND VISUALIZATION, 2002.
Since 2001, I have been working on texture synthesis on images and surfaces.
This research includes supervision of students from Ecole Polytechnique
and collaboration with Microsoft Research China.
Jingdan Zhang, Kun Zhou, Luiz Velho, Baining Guo, and Heung-Yeung.
"Synthesis of Progressively Variant Textures on Arbitrary Surfaces".
ACM Transactions on Graphics, 22(3):295-302, July 2003
Regis Destobbeleire and Luiz Velho.
Rapport de Stage d'Option Scientifique TR-02-08, Ecole Polytechnique, June 2002.
Paul Billault and Luiz Velho.
"Texture Syntesis Algorithms".
Rapport de stage d'option scientifique, Ecole Polytechnique, June 2001.
Point-Based Modeling and Rendering
My interest in 3D photography naturally lead to a research on point-based
modeling and rendering.
Vinicius Mello, Luiz Velho, and Gabriel Taubin.
"Computing the In/Out function of Point Clouds".
In Proceedings of the 8th ACM Symposium on Solid Modeling and Applications, 2003.
Boris Mederos, Luiz Velho, and Luiz Henrique de Figueiredo.
"Moving Least Squares Multiresolution Surface Approximation".
In Proceedings of SIBGRAPI 2003 - XVI Brazilian Symposium on Computer Graphics and Image Processing. IEEE Press, 2003.
Esdras Medeiros, Luiz Velho, and Helio Lopes.
"A Topological Framework for Advancing Front Triangulation".
In Proceedings of SIBGRAPI 2003 - XVI Brazilian Symposium on Computer Graphics and Image Processing, 2003
In 2001, I started to do research on subdivision techniques. Some of the results
include: a new scheme that generalizes C4 box splines; a semi-regular
refinement method for triangulated quadrangulations, and procedural
synthesis on subdivision surfaces.
L. Velho and D. Zorin, 2001,
CAGD Special Issue on Subdivision Techniques.
L. Velho, 2001,
"Using Semi Regular 4-8 Refinement for Subdivision",
Journal of Graphics Tools.
L. Velho and J. Gomes, 2001,
"Quasi 4-8 Subdivision",
Luiz Velho, Ken Perlin, Lexing Ying and Henning Biermann.
"Procedural Shape Synthesis on Subdivision Surfaces",
Computer and Graphics, 26(6), 2002.
Links: (see also links under
Hierarchical 4-K Meshes and 4-8 Subdivision
Hierarchical 4-K Meshes
Hierarchical 4-K Meshes constitue a powerful structure
for adaptive variable resolution representation of two dimensional
I am currently extending this framework to 3D with my former PhD student Vinicius Mello.
Fernado de Goes, Siome Goldenstein, and Luiz Velho. "A Simple and Flexible Framework to Adapt Dynamic Meshes". Computer and Graphics, 2008.
Vinicius Mello, Luiz Velho, Paulo Roma Cavalcanti, and Claudio Silva.
"A Generic Programming Approach to Multiresolution Spatial Decompositions",
volume Visualization and Mathematics III. Springer Verlag, 2002
L. Velho, 2001,
"Four-Face Cluster Simplification",
In Proceedings of Shape Modeling International.
L. Velho and J. Gomes, 2000,
"Variable Resolution 4-K Meshes: Concepts and Applications",
Computer Graphics Forum.
L. Velho, L. H. Figueiredo, and J. Gomes, 2000,
"A Unified Approach for Hierarchical Adaptive Tesselation of Surfaces",
ACM Transactions on Graphics.
L. Velho, L. H. Figueiredo, and J. Gomes, 1999,
"Hierarchical Generalized Triangle Strips",
The Visual Computer, Springer-Verlag.
In 1990, I became interested in implicitly defined surfaces
and their applications.
Since then, I have done research on modeling, rendering and
animation with implicit surfaces.
In the area of modeling, I employed multiscale analysis and
wavelets for the construction of implicit models, as well as,
for the conversion of parametric to implicit representations.
In the area of rendering, I have developed techniques for
polygonization of implicit surfaces.
More recently (1996), I created a method for applying 2D
textures onto implicit surfaces.
In the area of animation, I have done
some work on physical simulation of deformable models.
(see also papers under
R. Zonenschein, J. Gomes, L. Velho and L. H. Figueiredo, 1998,
"Controlling Texture Mapping onto Implicit Surfaces with Particle Systems",
Proceedings Third International Workshop on Implicit Surfaces, p. 1-138,
ACM-Siggraph / Eurographics.
L. Velho, R. Zonenschein, L. H. Figueredo and J. Gomes, 1997,
"Texturing Implicit Surfaces with Particle Systems",
SIGGRAPH'97 Visual Proceedings, p. 172.
L. Velho, D. Terzopulos and J. Gomes, 1997,
"Implicit Manifolds, Triangulations and Dynamics",
Journal of Neural, Parallel and Scientific Computations, 5(2):103-120.
L. Velho and J. Gomes, 1996,
"Approximate Conversion of Parametric to Implicit Surfaces"
Computer Graphics Forum, 15(5):327-338, Eurographics.
L. Velho and J. Gomes, 1991,
"A Dynamics Simulation Environment for Implicit Objects using Discrete Models"
Proceedings of 2nd Eurographics Workshop on Animation and Simulation, p. 183-190.
I have also written a book on implicit objects:
My research on implicit surfaces lead me to study the problem of
constructing piecewise linear approximations of surfaces.
Initially, I focused on adaptive polygonization of implicit
surfaces. Subsequently, I investigated also the tesselation of
Finally, I developed a unified framework for creating multiresolution
meshes from both parametric and implicit surfaces.
This work was the basis for surface representation schemes,
such as hierarchical triangle strips.
(see also papers under
hierarchical 4-k meshes
L. Velho, L. H. Figueiredo and J. Gomes, 1997,
"A methodology for piecewise linear approximation of surfaces",
Journal of the Brazilian Computer Society, 3(3):30-42.
L. Velho, 1996,
"Simple and Efficient Polygonization of Implicit Surfaces"
Journal of Graphics Tools, 1(2):5-25.
L. Velho and L. H. Figueiredo, 1996,
"Optimal adaptive polygonal approximation of parametric surfaces",
Proceedings of SIBGRAPI'96, p. 127-133.
L. H. Figueiredo, J. Gomes, D. Terzopoulos and L. Velho, 1992,
"Physically-based methods for polygonization of implicit surfaces",
Proceedings of Graphics Interface'92, p. 250-257.
L. Velho, 1990,
"Adaptive Polygonization of Implicit Surfaces Using Simplicial Decomposition
and Boundary Constraint",
Proceedings of Eurographics'90, p. 125-136.
Applications of Wavelets in Computer Graphics
Since 1994, I have been investigating applications of wavelets
in computer graphics. My work in this area includes multiscale
implicit models and multiresolution paint systems.
L. Velho, D, Terzopoulos and J. Gomes, 1995,
"Constructing Implicit Shape Models from Boundary Data",
Journal of Graphical Models and Image Processing, 57(3):220-234.
L. Velho, D. Terzopoulos and J. Gomes, 1994,
"Multiscale Implicit Models",
Proceedings of SIBGRAPI'94, p. 93-100.
K. Perlin and L. Velho, 1995,
"Live Paint: Painting with Procedural Multiscale Textures",
(SIGGRAPH'95), Computer Graphics, p. 153-160.
L. Velho and K. Perlin, 1994,
"B-Spline Wavelet Paint",
Technical Sketch SIGGRAPH'94 and NYU Tech Report.
In the area of image processing, my research activity has been
I have worked on image compression, quantization
and special effects.
R. Silva, J. Gomes, and L. Velho, 1999
"Segmentation of Video Sequences using Volumetric Image Processing",
Proceedings of Eurographics Multimedia'99 Workshop.
J. Gomes, C. Mota, R. Silva and L. Velho, 1996,
"Image Effects Using Contractive Mappings",
Proceedings of SIBGRAPI'96, p. 313-320.
L. Velho, J. Gomes and M. Sobreiro, 1996,
"Color image quantization by pairwise clustering",
Proceedings of SIBGRAPI'96, p. 203-210.
L. Velho and C. Alvarenga, 1990,
"Image Compression by First Order Approximation",
Proceedings of IMAG'ECOM 90, p. 378-391.
I have also written a book on Image Processing:
I have done extensive work on digital halftoning.
L. Velho, and J. Gomes, 2002,
"Color Halftoning with Stochastic Dithering and Adaptive Clustering".
In Proceedings of the First European Conference on Color.
L. Velho, and J. Gomes, 1995,
"Stochastic Screening Dithering with Adaptive Clustering",
(SIGGRAPH'95), Computer Graphics, p. 3-276.
L. Velho, and J. Gomes, 1991,
"Digital Halftoning with Space Filling Curves",
(SIGGRAPH'91), Computer Graphics, 25(4):81-90.
L. Velho, 1991,
Proceedings of SIBGRAPI'91, p. 167-178.
I did some work on virtual reality as part of the development
of Visorama. This system, among other things, employs image-based
rendering techniques for real-time visualization of panoramas.
- L. Velho, J. Gomes, A. Parente, A. Matos and H. Siffert, 1996,
"The Visorama System: A Functional Overview of a New Virtual Reality Environment",
Proceedings of CGI'96, p. 205-212.
- A. Matos, J. Gomes, L. Velho, A. Parente, and H. Siffert, 1998,
"Visorama: A Complete Virtual Panorama System",
SIGGRAPH 98 Conference Abstract and Applications, p. 252.
A. Matos, J. Gomes, and L. Velho.
"Cache Management for Real Time Visualization of 2D Data Sets".
Proceedings of SIBGRAPI 98, p. 111-118.
In the area of computer animation, my early work (1989)
was on procedural animation systems.
More recent work is dedicated to processing of motion capture data,
which has also been the subject of a Master's Thesis under my
Paula Salgado Lucena, Marcelo Gattass, and Luiz Velho.
"Expressive Talking Heads: A Study on Speech and Facial Expression in Virtual Characters".
Revista SCIENTIA, 2002.
F. Silva, L. Velho, J. Gomes and S. Goldenstein, 1999,
"Motion Cyclification by Time x Frequency Warping",
Proceedings of SIBGRAPI'99.
F. Silva, L. Velho, J. Gomes and P. Roma, 1997,
"An Architecture for Motion Capture Based Animation",
Proccedings of SIBGRAPI'97, p. 49-56.
F. Silva, L. Velho, J. Gomes and P. Roma, 1997,
"A New Interface Paradigm for Motion Capture Based Animation Systems",
8th EUROGRAPHICS Workshop on Computer Animation and Simulation, p. 19-36.
L. Velho, 1989,
"Scripts: On The Description of Computer Animated Image",
Proceedings of SIBGRAPI'89, p. 509-518.
Warping and Morphing
I have done some research in warping and morphing techniques.
I also wrote a book on this subject
J. Gomes, L. Darsa, B. Costa, and L. Velho,
"A system's architecture for warping and morphing af graphical objects",
Proceedings of SIBGRAPI 98, p. 192-199.
Theory of Computer Graphics
My research on theoretical aspects of computer graphics
is mainly concerned with the formulation
of general mathematical models for graphical objects.
J. Gomes, B. Costa, L. Darsa and L. Velho, 1996,
The Visual Computer, 12(6):269-282.
J. Gomes and L. Velho, 1995,
"Abstraction Paradigms for Computer Graphics",
The Visual Computer, 11(5):227-239.
L. Velho, 1993,
in Modeling in Computer Graphics (SIGGRAPH'93 Course Notes).
In addition to the above topics, I have also done some research in
Antonia Lucinelma Pessoa Albuquerque and Luiz Velho.
"Togetherness through Virtual Worlds: How real can be that Presence?".
Fifth Annual International Workshop Presence 2002.
S. Pinheiro, J. Gomes, and L. Velho, 1999,
"Interactive Specification of 3D Displacement Vectors Using Arcball",
Proceedings of Computer Graphics International.
L. Velho, 1988,
"Graphics Interface Design Using Unix Tools",
Proceedings of Ausgraph '88, p. 291-296.
A review of my research in Procedural Methods and Multiresolution Models
was presented in this invited plenary talk at SIBGRAPI 2002.
Slides - PDF format ]
An overview of my academic career from 1976 to 1996 can be
found in this Memorial, presented
as part of my professorship application at IMPA.
Slides - PDF format ]