4,637 research outputs found
Low-Light Enhancement in the Frequency Domain
Decreased visibility, intensive noise, and biased color are the common
problems existing in low-light images. These visual disturbances further reduce
the performance of high-level vision tasks, such as object detection, and
tracking. To address this issue, some image enhancement methods have been
proposed to increase the image contrast. However, most of them are implemented
only in the spatial domain, which can be severely influenced by noise signals
while enhancing. Hence, in this work, we propose a novel residual recurrent
multi-wavelet convolutional neural network R2-MWCNN learned in the frequency
domain that can simultaneously increase the image contrast and reduce noise
signals well. This end-to-end trainable network utilizes a multi-level discrete
wavelet transform to divide input feature maps into distinct frequencies,
resulting in a better denoise impact. A channel-wise loss function is proposed
to correct the color distortion for more realistic results. Extensive
experiments demonstrate that our proposed R2-MWCNN outperforms the
state-of-the-art methods quantitively and qualitatively.Comment: 8 page
Extremely Low-light Image Enhancement with Scene Text Restoration
Deep learning-based methods have made impressive progress in enhancing
extremely low-light images - the image quality of the reconstructed images has
generally improved. However, we found out that most of these methods could not
sufficiently recover the image details, for instance, the texts in the scene.
In this paper, a novel image enhancement framework is proposed to precisely
restore the scene texts, as well as the overall quality of the image
simultaneously under extremely low-light images conditions. Mainly, we employed
a self-regularised attention map, an edge map, and a novel text detection loss.
In addition, leveraging synthetic low-light images is beneficial for image
enhancement on the genuine ones in terms of text detection. The quantitative
and qualitative experimental results have shown that the proposed model
outperforms state-of-the-art methods in image restoration, text detection, and
text spotting on See In the Dark and ICDAR15 datasets
A Multi-scale Generalized Shrinkage Threshold Network for Image Blind Deblurring in Remote Sensing
Remote sensing images are essential for many earth science applications, but
their quality can be degraded due to limitations in sensor technology and
complex imaging environments. To address this, various remote sensing image
deblurring methods have been developed to restore sharp, high-quality images
from degraded observational data. However, most traditional model-based
deblurring methods usually require predefined hand-craft prior assumptions,
which are difficult to handle in complex applications, and most deep
learning-based deblurring methods are designed as a black box, lacking
transparency and interpretability. In this work, we propose a novel blind
deblurring learning framework based on alternating iterations of shrinkage
thresholds, alternately updating blurring kernels and images, with the
theoretical foundation of network design. Additionally, we propose a learnable
blur kernel proximal mapping module to improve the blur kernel evaluation in
the kernel domain. Then, we proposed a deep proximal mapping module in the
image domain, which combines a generalized shrinkage threshold operator and a
multi-scale prior feature extraction block. This module also introduces an
attention mechanism to adaptively adjust the prior importance, thus avoiding
the drawbacks of hand-crafted image prior terms. Thus, a novel multi-scale
generalized shrinkage threshold network (MGSTNet) is designed to specifically
focus on learning deep geometric prior features to enhance image restoration.
Experiments demonstrate the superiority of our MGSTNet framework on remote
sensing image datasets compared to existing deblurring methods.Comment: 12 pages
SyreaNet: A Physically Guided Underwater Image Enhancement Framework Integrating Synthetic and Real Images
Underwater image enhancement (UIE) is vital for high-level vision-related
underwater tasks. Although learning-based UIE methods have made remarkable
achievements in recent years, it's still challenging for them to consistently
deal with various underwater conditions, which could be caused by: 1) the use
of the simplified atmospheric image formation model in UIE may result in severe
errors; 2) the network trained solely with synthetic images might have
difficulty in generalizing well to real underwater images. In this work, we,
for the first time, propose a framework \textit{SyreaNet} for UIE that
integrates both synthetic and real data under the guidance of the revised
underwater image formation model and novel domain adaptation (DA) strategies.
First, an underwater image synthesis module based on the revised model is
proposed. Then, a physically guided disentangled network is designed to predict
the clear images by combining both synthetic and real underwater images. The
intra- and inter-domain gaps are abridged by fully exchanging the domain
knowledge. Extensive experiments demonstrate the superiority of our framework
over other state-of-the-art (SOTA) learning-based UIE methods qualitatively and
quantitatively. The code and dataset are publicly available at
https://github.com/RockWenJJ/SyreaNet.git.Comment: 7 pages; 10 figure
You Only Need 90K Parameters to Adapt Light: A Light Weight Transformer for Image Enhancement and Exposure Correction
Challenging illumination conditions (low-light, under-exposure and
over-exposure) in the real world not only cast an unpleasant visual appearance
but also taint the computer vision tasks. After camera captures the raw-RGB
data, it renders standard sRGB images with image signal processor (ISP). By
decomposing ISP pipeline into local and global image components, we propose a
lightweight fast Illumination Adaptive Transformer (IAT) to restore the normal
lit sRGB image from either low-light or under/over-exposure conditions.
Specifically, IAT uses attention queries to represent and adjust the
ISP-related parameters such as colour correction, gamma correction. With only
~90k parameters and ~0.004s processing speed, our IAT consistently achieves
superior performance over SOTA on the current benchmark low-light enhancement
and exposure correction datasets. Competitive experimental performance also
demonstrates that our IAT significantly enhances object detection and semantic
segmentation tasks under various light conditions. Training code and pretrained
model is available at
https://github.com/cuiziteng/Illumination-Adaptive-Transformer.Comment: 23 page
Unsupervised Low Light Image Enhancement Using SNR-Aware Swin Transformer
Image captured under low-light conditions presents unpleasing artifacts,
which debilitate the performance of feature extraction for many upstream visual
tasks. Low-light image enhancement aims at improving brightness and contrast,
and further reducing noise that corrupts the visual quality. Recently, many
image restoration methods based on Swin Transformer have been proposed and
achieve impressive performance. However, On one hand, trivially employing Swin
Transformer for low-light image enhancement would expose some artifacts,
including over-exposure, brightness imbalance and noise corruption, etc. On the
other hand, it is impractical to capture image pairs of low-light images and
corresponding ground-truth, i.e. well-exposed image in same visual scene. In
this paper, we propose a dual-branch network based on Swin Transformer, guided
by a signal-to-noise ratio prior map which provides the spatial-varying
information for low-light image enhancement. Moreover, we leverage unsupervised
learning to construct the optimization objective based on Retinex model, to
guide the training of proposed network. Experimental results demonstrate that
the proposed model is competitive with the baseline models
Toward Flare-Free Images: A Survey
Lens flare is a common image artifact that can significantly degrade image
quality and affect the performance of computer vision systems due to a strong
light source pointing at the camera. This survey provides a comprehensive
overview of the multifaceted domain of lens flare, encompassing its underlying
physics, influencing factors, types, and characteristics. It delves into the
complex optics of flare formation, arising from factors like internal
reflection, scattering, diffraction, and dispersion within the camera lens
system. The diverse categories of flare are explored, including scattering,
reflective, glare, orb, and starburst types. Key properties such as shape,
color, and localization are analyzed. The numerous factors impacting flare
appearance are discussed, spanning light source attributes, lens features,
camera settings, and scene content. The survey extensively covers the wide
range of methods proposed for flare removal, including hardware optimization
strategies, classical image processing techniques, and learning-based methods
using deep learning. It not only describes pioneering flare datasets created
for training and evaluation purposes but also how they were created. Commonly
employed performance metrics such as PSNR, SSIM, and LPIPS are explored.
Challenges posed by flare's complex and data-dependent characteristics are
highlighted. The survey provides insights into best practices, limitations, and
promising future directions for flare removal research. Reviewing the
state-of-the-art enables an in-depth understanding of the inherent complexities
of the flare phenomenon and the capabilities of existing solutions. This can
inform and inspire new innovations for handling lens flare artifacts and
improving visual quality across various applications
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