Active Learning and Discovery of Object Categories in the Presence of Unnameable Instances

Christoph Kading, Alexander Freytag, Erik Rodner, Paul Bodesheim, Joachim Denzler; The IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015, pp. 4343-4352

Abstract


Current visual recognition algorithms are "hungry" for data but massive annotation is extremely costly. Therefore, active learning algorithms are required that reduce labeling efforts to a minimum by selecting examples that are most valuable for labeling. In active learning, all categories occurring in collected data are usually assumed to be known in advance and experts should be able to label every requested instance. But do these assumptions really hold in practice? Could you name all categories in every image? Existing algorithms completely ignore the fact that there are certain examples where an oracle can not provide an answer or which even do not belong to the current problem domain. Ideally, active learning techniques should be able to discover new classes and at the same time cope with queries an expert is not able or willing to label. To meet these observations, we present a variant of the expected model output change principle for active learning and discovery in the presence of unnameable instances. Our experiments show that in these realistic scenarios, our approach substantially outperforms previous active learning methods, which are often not even able to improve with respect to the baseline of random query selection.

Related Material


[pdf]
[bibtex]
@InProceedings{Kading_2015_CVPR,
author = {Kading, Christoph and Freytag, Alexander and Rodner, Erik and Bodesheim, Paul and Denzler, Joachim},
title = {Active Learning and Discovery of Object Categories in the Presence of Unnameable Instances},
booktitle = {The IEEE Conference on Computer Vision and Pattern Recognition (CVPR)},
month = {June},
year = {2015}
}