Zohar Levi

 

Email:

zohar  cims.nyu.edu

Address:

Computer Science and Mathematics

Courant Institute of Mathematical Sciences

Media Research Laboratory

Vision, Learning and Graphics Group

New York University

719 Broadway, 12th floor

New York, NY 10003

 

I am a postdoc researcher at the Courant Institute of Mathematical Sciences, New York University, working with Prof. Denis Zorin.

 

I earned my Ph.D. in Computer Science (2013) from the Technion - Israel Institute of Technology, under the supervision of Prof. Craig Gotsman.

I earned my M.Sc. in Computer Science (2007) from the Tel-Aviv University, Israel, under the supervision of Prof. David Levin.

I earned my B.A. in Computer Science (2004) from Tel-Aviv-Yaffo Academic College, Israel.

 

Research Interests

 

o   Computer Graphics

o   Geometry Processing

o   Physical Simulation

o   Computer Vision

 

 

Publications

 

As-Rigid-As-Possible Mesh Animation

Zohar Levi, Craig Gotsman

(Preprint)

 

Abstract: We improve the As-Rigid-As-Possible (ARAP) animation technique in two aspects. First, we introduce a new ARAP energy, named SR-ARAP, which has a consistent discretization for surfaces (triangle meshes). The quality of our new surface deformation scheme competes with the quality of the volumetric ARAP deformation (for tetrahedral meshes). Second, we propose a new ARAP shape interpolation method that is superior to prior art also based on ARAP energy. This method is compatible with our new SR-ARAP energy, and with the ARAP volume energy.

 

[YouTube]

Shape Deformation via Interior RBF

Zohar Levi, David Levin

IEEE Transactions on Visualization and Computer Graphics, 2014

 

Abstract: We present a new framework for real-time shape deformation with local shape preservation and volume control. Given a 3D object, in any form, one would like to manipulate the object using convenient handles, so that the resulting shape is a natural variation of the given object. It is also important that the deformation is controlled, thereby enabling localized changes that do not influence nearby branches. For example, given a horse model, a movement of one of its hooves should not affect the other hooves. Another goal is the minimization of local shape distortion throughout the object. The first ingredient of our method is the use of Interior Radial Basis Functions (IRBF), where the functions are radial with respect to interior distances within the object. The second important ingredient is the reduction of local distortions by minimizing the distortion of a set of spheres placed within the object. Our method achieves the goals of convenient shape manipulation and local influence property, and improves the latest state-of-the-art cage-based methods by replacing the cage with the more flexible IRBF centers. The latter enables extra flexibility and fully automated construction, as well as simpler formulation.

 

[PDF] [Movie] [YouTube] [Poster] [Slides]

ArtiSketch: A System for Articulated Sketch Modeling

Zohar Levi, Craig Gotsman

Eurographics (Computer Graphics Forum), 2013

 

Abstract: We present ArtiSketch - a system which allows the conversion of a wealth of existing 2D content into 3D content by users who do not necessarily possess artistic skills. Using ArtiSketch, a novice user may describe a 3D model as a set of articulated 2D sketches of a shape from different viewpoints. ArtiSketch then automatically converts the sketches to an articulated 3D object. Using common interactive tools, the user provides an initial estimate of the 3D skeleton pose for each frame, which ArtiSketch refines to be consistent between frames. This skeleton may then be manipulated independently to generate novel poses of the 3D model.

 

[PDF] [Movie] [YouTube] [Slides]

D-Snake: Image Registration by As-Similar-As-Possible Template Deformation

Zohar Levi, Craig Gotsman

IEEE Transactions on Visualization and Computer Graphics, 2013

 

Abstract: We describe a snake-type method for shape registration in 2D and 3D, by fitting a given polygonal template to an acquired image or volume data. The snake aspires to fit itself to the data in a shape which is locally As-Similar-As-Possible (ASAP) to the template. Our ASAP regulating force is based on the Moving Least Squares (MLS) similarity deformation. Combining this force with the traditional internal and external forces associated with a snake leads to a powerful and robust registration algorithm, capable of extracting precise shape information from image data.

 

[PDF] [Movie] [YouTube]

 

 

Theses

 

MLS-Based Remeshing for Improving Surface Approximation

Zohar Levi, David Levin

M.Sc. thesis, Tel-Aviv University, 2007

 

Abstract: We present a remeshing technique for a better approximation of functions and surfaces. Given a triangulation of a surface, find a triangulation with the same number of vertices, which best approximates the underlying surface. The vertices are redistributed according to a local function error estimation to be close as possible to a MLS surface, which is used to approximate the source surface of the input mesh. A further improvement is achieved by an edge-flip algorithm. Moreover, we show two practical heuristics for choosing parameters for the MLS, and suggest a way to measure the quality of the remeshing.