PASCAL - Pattern Analysis, Statistical Modelling and Computational Learning

Discriminative Subsequence Mining for Action Classification
Sebastian Nowozin, Goekhan BakIr and Koji Tsuda
In: IEEE International Conference on Computer Vision (ICCV2007), Oct 2007, Rio de Janeiro, Brasil.

Abstract

Recent approaches to action classification in videos have used sparse spatio-temporal words encoding local appearance around interesting movements. Most of these approaches use a histogram representation, discarding the temporal order among features. But this ordering information can contain important information about the action itself, e.g. consider the sport disciplines of hurdle race and long jump, where the global temporal order of motions (running, jumping) is important to discriminate between the two. In this work we propose to use a sequential representation which retains this temporal order. Further, we introduce Discriminative Subsequence Mining to find optimal discriminative subsequence patterns. In combination with the LPBoost classifier, this amounts to simultaneously learning a classification function and performing feature selection in the space of all possible feature sequences. The resulting classifier linearly combines a small number of interpretable decision functions, each checking for the presence of a single discriminative pattern. The classifier is benchmarked on the KTH action classification data set and outperforms the best known results in the literature.

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EPrint Type:Conference or Workshop Item (Paper)
Additional Information:Software available at http://www.kyb.mpg.de/bs/people/nowozin/pboost/
Project Keyword:Project Keyword UNSPECIFIED
Subjects:Machine Vision
Learning/Statistics & Optimisation
ID Code:3106
Deposited By:Sebastian Nowozin
Deposited On:19 December 2007