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Fall 2010 GRASP Seminar – Irfan Essa, Georgia Institute of Technology, “Two Talks on Video Analysis: (1) Segmentation of Video and (2) Prediction of Actions in Video”

September 24, 2010 @ 11:00 am - 12:00 pm

Abstract: My research group is focused on a variety if approaches for
video analysis and synthesis. In this talk, I will focus on two of our recent
efforts.  One effort aimed at robust
spatio-temporal segmentation of video and another on using motion and flow to
predict actions from video. 

In the first part of the talk, I will present an efficient
and scalable technique for spatio-temporal segmentation of long video sequences
using a hierarchical graph-based algorithm. In this effort, we begin by over
segmenting a volumetric video graph into space-time regions grouped by
appearance. We then construct a “region graph” over the obtained segmentation
and iteratively repeat this process over multiple levels to create a tree of
spatio-temporal segmentations. This hierarchical approach generates high
quality segmentations, which are temporally coherent with stable region
boundaries, and allows subsequent applications to choose from varying levels of
granularity. We further improve segmentation quality by using dense optical
flow to guide temporal connections in the initial graph. I will demonstrate a
variety of examples of how this robust segmentation works, and will show
additional examples of video-retargeting that use the saliency from this
segmentation approach.  (Matthias
Grundmann, Vivek Kwatra, Mei Han, Irfan Essa, CVPR 2010, in collaboration with
Google Research).

In the second part of this talk, I will show that
constrained multi-agent events can be analyzed and even predicted from video.
Such analysis requires estimating the global movements of all players in the
scene at any time, and is needed for modeling and predicting how the
multi-agent play evolves over time on the field. To this end, we propose a
novel approach to detect the locations of where the play evolution will
proceed, e.g. where interesting events will occur, by tracking player positions
and movements over time. To achieve this, we extract the ground level sparse
movement of players in each time-step, and then generate a dense motion field.
Using this field we detect locations where the motion converges, implying
positions towards which the play is evolving. I will show examples of how we
have tested this approach for soccer, basketball and hockey. (Kihwan Kim,
Matthias Grundmann, Ariel Shamir, Iain Matthews, Jessica Hodgins, Irfan Essa,
CVPR 2010, in collaboration with Disney Research).

Time permitting, I will show some more videos of our recent
work on video analysis and synthesis. For more information, papers, and videos,
see my website at http://prof.irfanessa.com/


- Learn More

Irfan Essa is a Professor in the School of Interactive
Computing(iC) of the College of Computing (CoC), and Adjunct Professor in the
School of Electrical and Computer Engineering, Georgia Institute of Technology
(GA Tech), in Atlanta, Georgia, USA.

Irfan Essa works in the areas of Computer Vision, Computer
Graphics, Computational Perception, Robotics and Computer Animation, with
potential impact on Video Analysis and Production (e.g., Computational
Photography & Video, Image-based Modeling and Rendering, etc.) Human
Computer Interaction, and Artificial Intelligence research. Specifically, he is
interested in the analysis, interpretation, authoring, and synthesis (of
video), with the goals of building aware environments, recognizing, modeling
human activities, and behaviors, and developing dynamic and generative
representations of time-varying streams. He has published over a 150 scholarly
articles in leading journals and conference venues on these topics and has
awards for his research and teaching.

He joined Georgia Tech Faculty in 1996 after his earning his
MS (1990), Ph.D. (1994), and holding research faculty position at the
Massachusetts Institute of Technology (Media Lab) [1988-1996]. His Doctoral
Research was in the area of Facial Recognition, Analysis, and Synthesis.


September 24, 2010
11:00 am - 12:00 pm
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