12,301 research outputs found
Semantic Video CNNs through Representation Warping
In this work, we propose a technique to convert CNN models for semantic
segmentation of static images into CNNs for video data. We describe a warping
method that can be used to augment existing architectures with very little
extra computational cost. This module is called NetWarp and we demonstrate its
use for a range of network architectures. The main design principle is to use
optical flow of adjacent frames for warping internal network representations
across time. A key insight of this work is that fast optical flow methods can
be combined with many different CNN architectures for improved performance and
end-to-end training. Experiments validate that the proposed approach incurs
only little extra computational cost, while improving performance, when video
streams are available. We achieve new state-of-the-art results on the CamVid
and Cityscapes benchmark datasets and show consistent improvements over
different baseline networks. Our code and models will be available at
http://segmentation.is.tue.mpg.deComment: ICCV 201
Rain Removal in Traffic Surveillance: Does it Matter?
Varying weather conditions, including rainfall and snowfall, are generally
regarded as a challenge for computer vision algorithms. One proposed solution
to the challenges induced by rain and snowfall is to artificially remove the
rain from images or video using rain removal algorithms. It is the promise of
these algorithms that the rain-removed image frames will improve the
performance of subsequent segmentation and tracking algorithms. However, rain
removal algorithms are typically evaluated on their ability to remove synthetic
rain on a small subset of images. Currently, their behavior is unknown on
real-world videos when integrated with a typical computer vision pipeline. In
this paper, we review the existing rain removal algorithms and propose a new
dataset that consists of 22 traffic surveillance sequences under a broad
variety of weather conditions that all include either rain or snowfall. We
propose a new evaluation protocol that evaluates the rain removal algorithms on
their ability to improve the performance of subsequent segmentation, instance
segmentation, and feature tracking algorithms under rain and snow. If
successful, the de-rained frames of a rain removal algorithm should improve
segmentation performance and increase the number of accurately tracked
features. The results show that a recent single-frame-based rain removal
algorithm increases the segmentation performance by 19.7% on our proposed
dataset, but it eventually decreases the feature tracking performance and
showed mixed results with recent instance segmentation methods. However, the
best video-based rain removal algorithm improves the feature tracking accuracy
by 7.72%.Comment: Published in IEEE Transactions on Intelligent Transportation System
Efficient Attention: Attention with Linear Complexities
Dot-product attention has wide applications in computer vision and natural
language processing. However, its memory and computational costs grow
quadratically with the input size. Such growth prohibits its application on
high-resolution inputs. To remedy this drawback, this paper proposes a novel
efficient attention mechanism equivalent to dot-product attention but with
substantially less memory and computational costs. Its resource efficiency
allows more widespread and flexible integration of attention modules into a
network, which leads to better accuracies. Empirical evaluations demonstrated
the effectiveness of its advantages. Efficient attention modules brought
significant performance boosts to object detectors and instance segmenters on
MS-COCO 2017. Further, the resource efficiency democratizes attention to
complex models, where high costs prohibit the use of dot-product attention. As
an exemplar, a model with efficient attention achieved state-of-the-art
accuracies for stereo depth estimation on the Scene Flow dataset. Code is
available at https://github.com/cmsflash/efficient-attention.Comment: To appear at WACV 202
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