2,354 research outputs found
Fine-Pruning: Joint Fine-Tuning and Compression of a Convolutional Network with Bayesian Optimization
When approaching a novel visual recognition problem in a specialized image
domain, a common strategy is to start with a pre-trained deep neural network
and fine-tune it to the specialized domain. If the target domain covers a
smaller visual space than the source domain used for pre-training (e.g.
ImageNet), the fine-tuned network is likely to be over-parameterized. However,
applying network pruning as a post-processing step to reduce the memory
requirements has drawbacks: fine-tuning and pruning are performed
independently; pruning parameters are set once and cannot adapt over time; and
the highly parameterized nature of state-of-the-art pruning methods make it
prohibitive to manually search the pruning parameter space for deep networks,
leading to coarse approximations. We propose a principled method for jointly
fine-tuning and compressing a pre-trained convolutional network that overcomes
these limitations. Experiments on two specialized image domains (remote sensing
images and describable textures) demonstrate the validity of the proposed
approach.Comment: BMVC 2017 ora
FastDeepIoT: Towards Understanding and Optimizing Neural Network Execution Time on Mobile and Embedded Devices
Deep neural networks show great potential as solutions to many sensing
application problems, but their excessive resource demand slows down execution
time, pausing a serious impediment to deployment on low-end devices. To address
this challenge, recent literature focused on compressing neural network size to
improve performance. We show that changing neural network size does not
proportionally affect performance attributes of interest, such as execution
time. Rather, extreme run-time nonlinearities exist over the network
configuration space. Hence, we propose a novel framework, called FastDeepIoT,
that uncovers the non-linear relation between neural network structure and
execution time, then exploits that understanding to find network configurations
that significantly improve the trade-off between execution time and accuracy on
mobile and embedded devices. FastDeepIoT makes two key contributions. First,
FastDeepIoT automatically learns an accurate and highly interpretable execution
time model for deep neural networks on the target device. This is done without
prior knowledge of either the hardware specifications or the detailed
implementation of the used deep learning library. Second, FastDeepIoT informs a
compression algorithm how to minimize execution time on the profiled device
without impacting accuracy. We evaluate FastDeepIoT using three different
sensing-related tasks on two mobile devices: Nexus 5 and Galaxy Nexus.
FastDeepIoT further reduces the neural network execution time by to
and energy consumption by to compared with the
state-of-the-art compression algorithms.Comment: Accepted by SenSys '1
Dense semantic labeling of sub-decimeter resolution images with convolutional neural networks
Semantic labeling (or pixel-level land-cover classification) in ultra-high
resolution imagery (< 10cm) requires statistical models able to learn high
level concepts from spatial data, with large appearance variations.
Convolutional Neural Networks (CNNs) achieve this goal by learning
discriminatively a hierarchy of representations of increasing abstraction.
In this paper we present a CNN-based system relying on an
downsample-then-upsample architecture. Specifically, it first learns a rough
spatial map of high-level representations by means of convolutions and then
learns to upsample them back to the original resolution by deconvolutions. By
doing so, the CNN learns to densely label every pixel at the original
resolution of the image. This results in many advantages, including i)
state-of-the-art numerical accuracy, ii) improved geometric accuracy of
predictions and iii) high efficiency at inference time.
We test the proposed system on the Vaihingen and Potsdam sub-decimeter
resolution datasets, involving semantic labeling of aerial images of 9cm and
5cm resolution, respectively. These datasets are composed by many large and
fully annotated tiles allowing an unbiased evaluation of models making use of
spatial information. We do so by comparing two standard CNN architectures to
the proposed one: standard patch classification, prediction of local label
patches by employing only convolutions and full patch labeling by employing
deconvolutions. All the systems compare favorably or outperform a
state-of-the-art baseline relying on superpixels and powerful appearance
descriptors. The proposed full patch labeling CNN outperforms these models by a
large margin, also showing a very appealing inference time.Comment: Accepted in IEEE Transactions on Geoscience and Remote Sensing, 201
Propagating Confidences through CNNs for Sparse Data Regression
In most computer vision applications, convolutional neural networks (CNNs)
operate on dense image data generated by ordinary cameras. Designing CNNs for
sparse and irregularly spaced input data is still an open problem with numerous
applications in autonomous driving, robotics, and surveillance. To tackle this
challenging problem, we introduce an algebraically-constrained convolution
layer for CNNs with sparse input and demonstrate its capabilities for the scene
depth completion task. We propose novel strategies for determining the
confidence from the convolution operation and propagating it to consecutive
layers. Furthermore, we propose an objective function that simultaneously
minimizes the data error while maximizing the output confidence. Comprehensive
experiments are performed on the KITTI depth benchmark and the results clearly
demonstrate that the proposed approach achieves superior performance while
requiring three times fewer parameters than the state-of-the-art methods.
Moreover, our approach produces a continuous pixel-wise confidence map enabling
information fusion, state inference, and decision support.Comment: To appear in the British Machine Vision Conference (BMVC2018
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