This paper considers the problem of action localization, where the objective is to determine when and where certain actions appear. We introduce a sampling strategy to produce 2D+t sequences of bounding boxes, called tubelets. Compared to state-of-the-art alternatives, this drastically reduces the number of hypotheses that are likely to include the action of interest. Our method is inspired by a recent technique introduced in the context of image localization. Beyond considering this technique for the first time for videos, we revisit this strategy for 2D+t sequences obtained from super-voxels. Our sampling strategy advantageously exploits a criterion that reflects how action related motion deviates from background motion. We demonstrate the interest of our approach by extensive experiments on two public datasets: UCF Sports and MSR-II. Our approach significantly outperforms the state-of-theart on both datasets, while restricting the search of actions to a fraction of possible bounding box sequences.
@InProceedings{JainCVPR2014,
author = "Jain, M. and van Gemert, J. C. and J\'egou, H. and Bouthemy, P.
and Snoek, C. G. M.",
title = "Action Localization by Tubelets from Motion",
booktitle = "IEEE Conference on Computer Vision and Pattern Recognition",
year = "2014",
url = "https://ivi.fnwi.uva.nl/isis/publications/2014/JainCVPR2014",
pdf = "https://ivi.fnwi.uva.nl/isis/publications/2014/JainCVPR2014/JainCVPR2014.pdf",
has_image = 1
}