3,539 research outputs found
Accelerating sparse restricted Boltzmann machine training using non-Gaussianity measures
In recent years, sparse restricted Boltzmann machines have gained popularity as unsupervised feature extractors. Starting from the observation that their training process is biphasic, we investigate how it can be accelerated: by determining when it can be stopped based on the non-Gaussianity of the distribution of the model parameters, and by increasing the learning rate when the learnt filters have locked on to their preferred configurations. We evaluated our approach on the CIFAR-10, NORB and GTZAN datasets
Lightweight Probabilistic Deep Networks
Even though probabilistic treatments of neural networks have a long history,
they have not found widespread use in practice. Sampling approaches are often
too slow already for simple networks. The size of the inputs and the depth of
typical CNN architectures in computer vision only compound this problem.
Uncertainty in neural networks has thus been largely ignored in practice,
despite the fact that it may provide important information about the
reliability of predictions and the inner workings of the network. In this
paper, we introduce two lightweight approaches to making supervised learning
with probabilistic deep networks practical: First, we suggest probabilistic
output layers for classification and regression that require only minimal
changes to existing networks. Second, we employ assumed density filtering and
show that activation uncertainties can be propagated in a practical fashion
through the entire network, again with minor changes. Both probabilistic
networks retain the predictive power of the deterministic counterpart, but
yield uncertainties that correlate well with the empirical error induced by
their predictions. Moreover, the robustness to adversarial examples is
significantly increased.Comment: To appear at CVPR 201
Recovering 6D Object Pose and Predicting Next-Best-View in the Crowd
Object detection and 6D pose estimation in the crowd (scenes with multiple
object instances, severe foreground occlusions and background distractors), has
become an important problem in many rapidly evolving technological areas such
as robotics and augmented reality. Single shot-based 6D pose estimators with
manually designed features are still unable to tackle the above challenges,
motivating the research towards unsupervised feature learning and
next-best-view estimation. In this work, we present a complete framework for
both single shot-based 6D object pose estimation and next-best-view prediction
based on Hough Forests, the state of the art object pose estimator that
performs classification and regression jointly. Rather than using manually
designed features we a) propose an unsupervised feature learnt from
depth-invariant patches using a Sparse Autoencoder and b) offer an extensive
evaluation of various state of the art features. Furthermore, taking advantage
of the clustering performed in the leaf nodes of Hough Forests, we learn to
estimate the reduction of uncertainty in other views, formulating the problem
of selecting the next-best-view. To further improve pose estimation, we propose
an improved joint registration and hypotheses verification module as a final
refinement step to reject false detections. We provide two additional
challenging datasets inspired from realistic scenarios to extensively evaluate
the state of the art and our framework. One is related to domestic environments
and the other depicts a bin-picking scenario mostly found in industrial
settings. We show that our framework significantly outperforms state of the art
both on public and on our datasets.Comment: CVPR 2016 accepted paper, project page:
http://www.iis.ee.ic.ac.uk/rkouskou/6D_NBV.htm
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