8,051 research outputs found
Automatically Designing CNN Architectures for Medical Image Segmentation
Deep neural network architectures have traditionally been designed and
explored with human expertise in a long-lasting trial-and-error process. This
process requires huge amount of time, expertise, and resources. To address this
tedious problem, we propose a novel algorithm to optimally find hyperparameters
of a deep network architecture automatically. We specifically focus on
designing neural architectures for medical image segmentation task. Our
proposed method is based on a policy gradient reinforcement learning for which
the reward function is assigned a segmentation evaluation utility (i.e., dice
index). We show the efficacy of the proposed method with its low computational
cost in comparison with the state-of-the-art medical image segmentation
networks. We also present a new architecture design, a densely connected
encoder-decoder CNN, as a strong baseline architecture to apply the proposed
hyperparameter search algorithm. We apply the proposed algorithm to each layer
of the baseline architectures. As an application, we train the proposed system
on cine cardiac MR images from Automated Cardiac Diagnosis Challenge (ACDC)
MICCAI 2017. Starting from a baseline segmentation architecture, the resulting
network architecture obtains the state-of-the-art results in accuracy without
performing any trial-and-error based architecture design approaches or close
supervision of the hyperparameters changes.Comment: Accepted to Machine Learning in Medical Imaging (MLMI 2018
Multi-level Feature Fusion-based CNN for Local Climate Zone Classification from Sentinel-2 Images: Benchmark Results on the So2Sat LCZ42 Dataset
As a unique classification scheme for urban forms and functions, the local
climate zone (LCZ) system provides essential general information for any
studies related to urban environments, especially on a large scale. Remote
sensing data-based classification approaches are the key to large-scale mapping
and monitoring of LCZs. The potential of deep learning-based approaches is not
yet fully explored, even though advanced convolutional neural networks (CNNs)
continue to push the frontiers for various computer vision tasks. One reason is
that published studies are based on different datasets, usually at a regional
scale, which makes it impossible to fairly and consistently compare the
potential of different CNNs for real-world scenarios. This study is based on
the big So2Sat LCZ42 benchmark dataset dedicated to LCZ classification. Using
this dataset, we studied a range of CNNs of varying sizes. In addition, we
proposed a CNN to classify LCZs from Sentinel-2 images, Sen2LCZ-Net. Using this
base network, we propose fusing multi-level features using the extended
Sen2LCZ-Net-MF. With this proposed simple network architecture and the highly
competitive benchmark dataset, we obtain results that are better than those
obtained by the state-of-the-art CNNs, while requiring less computation with
fewer layers and parameters. Large-scale LCZ classification examples of
completely unseen areas are presented, demonstrating the potential of our
proposed Sen2LCZ-Net-MF as well as the So2Sat LCZ42 dataset. We also
intensively investigated the influence of network depth and width and the
effectiveness of the design choices made for Sen2LCZ-Net-MF. Our work will
provide important baselines for future CNN-based algorithm developments for
both LCZ classification and other urban land cover land use classification
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