ColloquiaColloquium Announcement: Baba Vemuri, Oct. 5th

[Margery Ishmael]

Computer Science Department: Colloquium Announcement

Date: Friday, October 5th at 2:30 pm
Venue: Ryerson Hall 251
Title: Deformable Pedal Curves & Surfaces: Hybrid Geometric Shape Models
Speaker: Baba C. Vemuri, Department of Computer & Information Sciences & 
Engineering, University of Florida

Abstract: Deformable models are very popular in the fields of Computer 
Vision and Computer Graphics and have been used extensively for various 
applications ranging from 2D/3D shape recovery from image data to 
animation.  More recently, hybrid models - models that include passive as 
well as active modeling components - have been widely used due to their 
ability to simultaneously provide a global and local shape description of 
an object.  In this class of models, the deformable superquadrics and 
variants thereof have been the most popular in the Computer Vision and 
Medical Imaging domains.

This talk will provide a brief introduction to the deformable 
superquadrics, point out its drawbacks and thereby establish the motivation 
for a new modeling scheme that is well suited for recovering 2D/3D shapes 
from image data.  A novel modeling scheme is introduced which consists of 
representing shapes by pedal curves and surfaces - pedal curves/surfaces 
are the loci of the foot of perpendiculars to the tangents of a fixed 
curve/surface from a fixed point called the pedal point.  By varying the 
location of the pedal point, one can synthesize a large class of shapes 
which exhibit both local and global deformations.  We introduce 
physics-based control for shaping these geometric models by letting the 
pedal point vary and use a dynamic spline a.k.a. "snake" to represent the 
position of this varying pedal point.  The model dubbed as a "snake pedal" 
(deformable pedal curve/surface) allows for interactive manipulation and 
control.  Novel and efficient numerical methods are then introduced for 
fitting this model to 3D data sets and examples of model fitting are 
shown.  Replacing the dynamic spline with an implicit curve and using the 
equations of geometric snake evolution allows for automatic changes in 
topology of the model.  Moreover, for the first time, it provided a means 
for the introduction of shape priors into the curve/surface evolution 
framework.  A variety of examples depicting the application of the model 
fitting algorithm for shape recovery from 2D to 3D image data sets will be 
interspersed throughout the talk.
http://www.cise.ufl.edu/~vemuri/

*The talk will be followed by refreshments in Ryerson 255*
Persons with disabilities who may need assistance, please call 773.834.8977

=========================================
Margery Ishmael
Department of Computer Science
1100 E. 58th Street
Chicago, IL. 60637
Tel. 773.834.8977 - Fax. 773.702.8487
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