Title: Speeding-up Object Detection Training for Robotics with FALKON,
Abstract: Latest deep learning methods for object detection provide remarkable
performance, but have limits when used in robotic applications. One of the most
relevant issues is the long training time, which is due to the large size and
imbalance of the associated training sets, characterized by few positive and a
large number of negative examples (i.e. background). Proposed approaches are
based on end-to-end learning by back-propagation [22] or kernel methods trained
with Hard Negatives Mining on top of deep features [8]. These solutions are
effective, but prohibitively slow for on-line applications. In this paper we
propose a novel pipeline for object detection that overcomes this problem and
provides comparable performance, with a 60x training speedup. Our pipeline
combines (i) the Region Proposal Network and the deep feature extractor from
[22] to efficiently select candidate RoIs and encode them into powerful
representations, with (ii) the FALKON [23] algorithm, a novel kernel-based
method that allows fast training on large scale problems (millions of points).
We address the size and imbalance of training data by exploiting the stochastic
subsampling intrinsic into the method and a novel, fast, bootstrapping
approach. We assess the effectiveness of the approach on a standard Computer
Vision dataset (PASCAL VOC 2007 [5]) and demonstrate its applicability to a
real robotic scenario with the iCubWorld Transformations [18] dataset.