Bottom up approach to Complex Event Recognition
Abstract
Recognition of complex events in unconstrained Internet videos is
a challenging research problem. In this symposium proposal, we
present a systematic decomposition of complex events into hierarchical
components and make an in-depth analysis of how existing
research are being used to cater to various levels of this hierarchy.
We also identify three key stages where we make novel
contributions which are necessary to not only improve the overall
recognition performance, but also develop richer understanding
of these events. At the lowest level, our contributions include (a)
compact covariance descriptors of appearance and motion features
used in sparse coding framework to recognize realistic actions and
gestures, and (b) a Lie-algebra based representation of dominant
camera motion present in video shots which can be used as a complementary
feature for video analysis. In the next level, we propose
an (c) efficient maximum likelihood estimate based representation
from low-level features computed from videos which demonstrates
state of the art performance in large scale visual concept detection,
and finally, we propose to (d) model temporal interactions between
concepts detected in video shots through two new discriminative
feature spaces derived from Linear dynamical systems which eventually
boosts event recognition performance. In all cases, we conduct
thorough experiments to demonstrate promising performance
gains over some of the prominent approaches.
Additional Material
This paper is a concise version of the
dissertation and was selected for oral presentation at the ACM MM 2013
Doctoral Symposium in Barcelona, Spain [3/13]. The entire
dissertation is also available here. A
video of the dissertation defense is attached for the interested:
Relevant Publications
[1] Subhabrata Bhattacharya, "Recognition of Complex Events in Open-Source
Web-Scale Videos: A Bottom up approach", In Proc. of ACM International
Conference on Multimedia (MM), Barcelona, ES, pp. 1035-1038, 2013.
[2] Subhabrata Bhattacharya, "Recognition of Complex Events in Open-source
Web-scale Videos: Features, Intermediate Representations and Their
Temporal Interactions", PhD thesis, University of Central Florida,
Orlando, FL, USA, 2013.
[3] Yu-Gang Jiang, Subhabrata Bhattacharya, Shih-Fu Chang, Mubarak Shah,
"High-Level Event Recognition in Unconstrained Videos", In International
Journal of Multimedia Information Retrieval (IJMIR), vol. 2, no. 2, pp.
2:73-101, 2013.