16 research outputs found
Self Paced Deep Learning for Weakly Supervised Object Detection
In a weakly-supervised scenario object detectors need to be trained using
image-level annotation alone. Since bounding-box-level ground truth is not
available, most of the solutions proposed so far are based on an iterative,
Multiple Instance Learning framework in which the current classifier is used to
select the highest-confidence boxes in each image, which are treated as
pseudo-ground truth in the next training iteration. However, the errors of an
immature classifier can make the process drift, usually introducing many of
false positives in the training dataset. To alleviate this problem, we propose
in this paper a training protocol based on the self-paced learning paradigm.
The main idea is to iteratively select a subset of images and boxes that are
the most reliable, and use them for training. While in the past few years
similar strategies have been adopted for SVMs and other classifiers, we are the
first showing that a self-paced approach can be used with deep-network-based
classifiers in an end-to-end training pipeline. The method we propose is built
on the fully-supervised Fast-RCNN architecture and can be applied to similar
architectures which represent the input image as a bag of boxes. We show
state-of-the-art results on Pascal VOC 2007, Pascal VOC 2010 and ILSVRC 2013.
On ILSVRC 2013 our results based on a low-capacity AlexNet network outperform
even those weakly-supervised approaches which are based on much higher-capacity
networks.Comment: To appear at IEEE Transactions on PAM
Effortless Deep Training for Traffic Sign Detection Using Templates and Arbitrary Natural Images
Deep learning has been successfully applied to several problems related to
autonomous driving. Often, these solutions rely on large networks that require
databases of real image samples of the problem (i.e., real world) for proper
training. The acquisition of such real-world data sets is not always possible
in the autonomous driving context, and sometimes their annotation is not
feasible (e.g., takes too long or is too expensive). Moreover, in many tasks,
there is an intrinsic data imbalance that most learning-based methods struggle
to cope with. It turns out that traffic sign detection is a problem in which
these three issues are seen altogether. In this work, we propose a novel
database generation method that requires only (i) arbitrary natural images,
i.e., requires no real image from the domain of interest, and (ii) templates of
the traffic signs, i.e., templates synthetically created to illustrate the
appearance of the category of a traffic sign. The effortlessly generated
training database is shown to be effective for the training of a deep detector
(such as Faster R-CNN) on German traffic signs, achieving 95.66% of mAP on
average. In addition, the proposed method is able to detect traffic signs with
an average precision, recall and F1-score of about 94%, 91% and 93%,
respectively. The experiments surprisingly show that detectors can be trained
with simple data generation methods and without problem domain data for the
background, which is in the opposite direction of the common sense for deep
learning
Local-HDP:Interactive Open-Ended 3D Object Categorization
We introduce a non-parametric hierarchical Bayesian approach for open-ended 3D object categorization, named the Local Hierarchical Dirichlet Process (Local-HDP). This method allows an agent to learn independent topics for each category incrementally and to adapt to the environment in time. Hierarchical Bayesian approaches like Latent Dirichlet Allocation (LDA) can transform low-level features to high-level conceptual topics for 3D object categorization. However, the efficiency and accuracy of LDA-based approaches depend on the number of topics that is chosen manually. Moreover, fixing the number of topics for all categories can lead to overfitting or underfitting of the model. In contrast, the proposed Local-HDP can autonomously determine the number of topics for each category. Furthermore, an inference method is proposed that results in a fast posterior approximation. Experiments show that Local-HDP outperforms other state-of-the-art approaches in terms of accuracy, scalability, and memory efficiency with a large margin