14 research outputs found
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
Removal of visual disruption caused by rain using cycle-consistent generative adversarial networks
This paper addresses the problem of removing rain disruption from images without blurring scene content, thereby retaining the visual quality of the image. This is particularly important in maintaining the performance of outdoor vision systems, which deteriorates with increasing rain disruption or degradation on the visual quality of the image. In this paper, the Cycle-Consistent Generative Adversarial Network (CycleGAN) is proposed as a more promising rain removal algorithm, as compared to the state-of-the-art Image De-raining Conditional Generative Adversarial Network (ID-CGAN). One of the main advantages of the CycleGAN is its ability to learn the underlying relationship between
the rain and rain-free domain without the need of paired domain examples, which is essential for rain removal as it is not possible to obtain the rain-free image under dynamic outdoor conditions. Based on the physical properties and the various types of rain phenomena [10], five broad categories of real rain distortions are proposed, which can be applied to the majority of outdoor rain conditions. For a fair comparison, both the ID-CGAN and CycleGAN were trained on the same set of 700 synthesized rain-and-ground-truth image-pairs. Subsequently, both networks were tested on real rain images, which fall broadly under these five categories. A comparison of the performance between the CycleGAN and the ID-CGAN demonstrated that the CycleGAN is superior in removing real rain distortions
Unsupervised Single Image Deraining with Self-supervised Constraints
Most existing single image deraining methods require learning supervised
models from a large set of paired synthetic training data, which limits their
generality, scalability and practicality in real-world multimedia applications.
Besides, due to lack of labeled-supervised constraints, directly applying
existing unsupervised frameworks to the image deraining task will suffer from
low-quality recovery. Therefore, we propose an Unsupervised Deraining
Generative Adversarial Network (UD-GAN) to tackle above problems by introducing
self-supervised constraints from the intrinsic statistics of unpaired rainy and
clean images. Specifically, we firstly design two collaboratively optimized
modules, namely Rain Guidance Module (RGM) and Background Guidance Module
(BGM), to take full advantage of rainy image characteristics: The RGM is
designed to discriminate real rainy images from fake rainy images which are
created based on outputs of the generator with BGM. Simultaneously, the BGM
exploits a hierarchical Gaussian-Blur gradient error to ensure background
consistency between rainy input and de-rained output. Secondly, a novel
luminance-adjusting adversarial loss is integrated into the clean image
discriminator considering the built-in luminance difference between real clean
images and derained images. Comprehensive experiment results on various
benchmarking datasets and different training settings show that UD-GAN
outperforms existing image deraining methods in both quantitative and
qualitative comparisons.Comment: 10 pages, 8 figure
Non-locally Enhanced Encoder-Decoder Network for Single Image De-raining
Single image rain streaks removal has recently witnessed substantial progress
due to the development of deep convolutional neural networks. However, existing
deep learning based methods either focus on the entrance and exit of the
network by decomposing the input image into high and low frequency information
and employing residual learning to reduce the mapping range, or focus on the
introduction of cascaded learning scheme to decompose the task of rain streaks
removal into multi-stages. These methods treat the convolutional neural network
as an encapsulated end-to-end mapping module without deepening into the
rationality and superiority of neural network design. In this paper, we delve
into an effective end-to-end neural network structure for stronger feature
expression and spatial correlation learning. Specifically, we propose a
non-locally enhanced encoder-decoder network framework, which consists of a
pooling indices embedded encoder-decoder network to efficiently learn
increasingly abstract feature representation for more accurate rain streaks
modeling while perfectly preserving the image detail. The proposed
encoder-decoder framework is composed of a series of non-locally enhanced dense
blocks that are designed to not only fully exploit hierarchical features from
all the convolutional layers but also well capture the long-distance
dependencies and structural information. Extensive experiments on synthetic and
real datasets demonstrate that the proposed method can effectively remove
rain-streaks on rainy image of various densities while well preserving the
image details, which achieves significant improvements over the recent
state-of-the-art methods.Comment: Accepted to ACM Multimedia 201