227 research outputs found
Subset Feature Learning for Fine-Grained Category Classification
Fine-grained categorisation has been a challenging problem due to small
inter-class variation, large intra-class variation and low number of training
images. We propose a learning system which first clusters visually similar
classes and then learns deep convolutional neural network features specific to
each subset. Experiments on the popular fine-grained Caltech-UCSD bird dataset
show that the proposed method outperforms recent fine-grained categorisation
methods under the most difficult setting: no bounding boxes are presented at
test time. It achieves a mean accuracy of 77.5%, compared to the previous best
performance of 73.2%. We also show that progressive transfer learning allows us
to first learn domain-generic features (for bird classification) which can then
be adapted to specific set of bird classes, yielding improvements in accuracy
Modelling Local Deep Convolutional Neural Network Features to Improve Fine-Grained Image Classification
We propose a local modelling approach using deep convolutional neural
networks (CNNs) for fine-grained image classification. Recently, deep CNNs
trained from large datasets have considerably improved the performance of
object recognition. However, to date there has been limited work using these
deep CNNs as local feature extractors. This partly stems from CNNs having
internal representations which are high dimensional, thereby making such
representations difficult to model using stochastic models. To overcome this
issue, we propose to reduce the dimensionality of one of the internal fully
connected layers, in conjunction with layer-restricted retraining to avoid
retraining the entire network. The distribution of low-dimensional features
obtained from the modified layer is then modelled using a Gaussian mixture
model. Comparative experiments show that considerable performance improvements
can be achieved on the challenging Fish and UEC FOOD-100 datasets.Comment: 5 pages, three figure
Adversarial Discriminative Sim-to-real Transfer of Visuo-motor Policies
Various approaches have been proposed to learn visuo-motor policies for
real-world robotic applications. One solution is first learning in simulation
then transferring to the real world. In the transfer, most existing approaches
need real-world images with labels. However, the labelling process is often
expensive or even impractical in many robotic applications. In this paper, we
propose an adversarial discriminative sim-to-real transfer approach to reduce
the cost of labelling real data. The effectiveness of the approach is
demonstrated with modular networks in a table-top object reaching task where a
7 DoF arm is controlled in velocity mode to reach a blue cuboid in clutter
through visual observations. The adversarial transfer approach reduced the
labelled real data requirement by 50%. Policies can be transferred to real
environments with only 93 labelled and 186 unlabelled real images. The
transferred visuo-motor policies are robust to novel (not seen in training)
objects in clutter and even a moving target, achieving a 97.8% success rate and
1.8 cm control accuracy.Comment: Under review for the International Journal of Robotics Researc
Towards Novel Class Discovery: A Study in Novel Skin Lesions Clustering
Existing deep learning models have achieved promising performance in
recognizing skin diseases from dermoscopic images. However, these models can
only recognize samples from predefined categories, when they are deployed in
the clinic, data from new unknown categories are constantly emerging.
Therefore, it is crucial to automatically discover and identify new semantic
categories from new data. In this paper, we propose a new novel class discovery
framework for automatically discovering new semantic classes from dermoscopy
image datasets based on the knowledge of known classes. Specifically, we first
use contrastive learning to learn a robust and unbiased feature representation
based on all data from known and unknown categories. We then propose an
uncertainty-aware multi-view cross pseudo-supervision strategy, which is
trained jointly on all categories of data using pseudo labels generated by a
self-labeling strategy. Finally, we further refine the pseudo label by
aggregating neighborhood information through local sample similarity to improve
the clustering performance of the model for unknown categories. We conducted
extensive experiments on the dermatology dataset ISIC 2019, and the
experimental results show that our approach can effectively leverage knowledge
from known categories to discover new semantic categories. We also further
validated the effectiveness of the different modules through extensive ablation
experiments. Our code will be released soon.Comment: 10 pages, 1 figure,Accepted by miccai 202
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