1,457 research outputs found
A Retinex-based Image Enhancement Scheme with Noise Aware Shadow-up Function
This paper proposes a novel image contrast enhancement method based on both a
noise aware shadow-up function and Retinex (retina and cortex) decomposition.
Under low light conditions, images taken by digital cameras have low contrast
in dark or bright regions. This is due to a limited dynamic range that imaging
sensors have. For this reason, various contrast enhancement methods have been
proposed. Our proposed method can enhance the contrast of images without not
only over-enhancement but also noise amplification. In the proposed method, an
image is decomposed into illumination layer and reflectance layer based on the
retinex theory, and lightness information of the illumination layer is
adjusted. A shadow-up function is used for preventing over-enhancement. The
proposed mapping function, designed by using a noise aware histogram, allows
not only to enhance contrast of dark region, but also to avoid amplifying
noise, even under strong noise environments.Comment: To appear in IWAIT-IFMIA 201
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
Empowering Low-Light Image Enhancer through Customized Learnable Priors
Deep neural networks have achieved remarkable progress in enhancing low-light
images by improving their brightness and eliminating noise. However, most
existing methods construct end-to-end mapping networks heuristically,
neglecting the intrinsic prior of image enhancement task and lacking
transparency and interpretability. Although some unfolding solutions have been
proposed to relieve these issues, they rely on proximal operator networks that
deliver ambiguous and implicit priors. In this work, we propose a paradigm for
low-light image enhancement that explores the potential of customized learnable
priors to improve the transparency of the deep unfolding paradigm. Motivated by
the powerful feature representation capability of Masked Autoencoder (MAE), we
customize MAE-based illumination and noise priors and redevelop them from two
perspectives: 1) \textbf{structure flow}: we train the MAE from a normal-light
image to its illumination properties and then embed it into the proximal
operator design of the unfolding architecture; and m2) \textbf{optimization
flow}: we train MAE from a normal-light image to its gradient representation
and then employ it as a regularization term to constrain noise in the model
output. These designs improve the interpretability and representation
capability of the model.Extensive experiments on multiple low-light image
enhancement datasets demonstrate the superiority of our proposed paradigm over
state-of-the-art methods. Code is available at
https://github.com/zheng980629/CUE.Comment: Accepted by ICCV 202
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