2,770 research outputs found
Progressive Joint Low-light Enhancement and Noise Removal for Raw Images
Low-light imaging on mobile devices is typically challenging due to
insufficient incident light coming through the relatively small aperture,
resulting in a low signal-to-noise ratio. Most of the previous works on
low-light image processing focus either only on a single task such as
illumination adjustment, color enhancement, or noise removal; or on a joint
illumination adjustment and denoising task that heavily relies on short-long
exposure image pairs collected from specific camera models, and thus these
approaches are less practical and generalizable in real-world settings where
camera-specific joint enhancement and restoration is required. To tackle this
problem, in this paper, we propose a low-light image processing framework that
performs joint illumination adjustment, color enhancement, and denoising.
Considering the difficulty in model-specific data collection and the ultra-high
definition of the captured images, we design two branches: a coefficient
estimation branch as well as a joint enhancement and denoising branch. The
coefficient estimation branch works in a low-resolution space and predicts the
coefficients for enhancement via bilateral learning, whereas the joint
enhancement and denoising branch works in a full-resolution space and
progressively performs joint enhancement and denoising. In contrast to existing
methods, our framework does not need to recollect massive data when being
adapted to another camera model, which significantly reduces the efforts
required to fine-tune our approach for practical usage. Through extensive
experiments, we demonstrate its great potential in real-world low-light imaging
applications when compared with current state-of-the-art methods
Au-SN Flip-Chip Solder Bump for Microelectronic and Optoelectronic Applications
As an alternative to the time-consuming solder pre-forms and pastes currently
used, a co-electroplating method of eutectic Au-Sn alloy was used in this
study. Using a co-electroplating process, it was possible to plate the Au-Sn
solder directly onto a wafer at or near the eutectic composition from a single
solution. Two distinct phases, Au5Sn and AuSn, were deposited at a composition
of 30at.%Sn. The Au-Sn flip-chip joints were formed at 300 and 400 degrees
without using any flux. In the case where the samples were reflowed at 300
degrees, only an (Au,Ni)3Sn2 IMC layer formed at the interface between the
Au-Sn solder and Ni UBM. On the other hand, two IMC layers, (Au,Ni)3Sn2 and
(Au,Ni)3Sn, were found at the interfaces of the samples reflowed at 400
degrees. As the reflow time increased, the thickness of the (Au,Ni)3Sn2 and
(Au,Ni)3Sn IMC layers formed at the interface increased and the eutectic
lamellae in the bulk solder coarsened.Comment: Submitted on behalf of TIMA Editions
(http://irevues.inist.fr/tima-editions
Elevated intracellular cAMP exacerbates vulnerability to oxidative stress in optic nerve head astrocytes.
Glaucoma is characterized by a progressive loss of retinal ganglion cells and their axons, but the underlying biological basis for the accompanying neurodegeneration is not known. Accumulating evidence indicates that structural and functional abnormalities of astrocytes within the optic nerve head (ONH) have a role. However, whether the activation of cyclic adenosine 3',5'-monophosphate (cAMP) signaling pathway is associated with astrocyte dysfunction in the ONH remains unknown. We report here that the cAMP/protein kinase A (PKA) pathway is critical to ONH astrocyte dysfunction, leading to caspase-3 activation and cell death via the AKT/Bim/Bax signaling pathway. Furthermore, elevated intracellular cAMP exacerbates vulnerability to oxidative stress in ONH astrocytes, and this may contribute to axonal damage in glaucomatous neurodegeneration. Inhibition of intracellular cAMP/PKA signaling activation protects ONH astrocytes by increasing AKT phosphorylation against oxidative stress. These results strongly indicate that activation of cAMP/PKA pathway has an important role in astrocyte dysfunction, and suggest that modulating cAMP/PKA pathway has therapeutic potential for glaucomatous ONH degeneration
GPS-GLASS: Learning Nighttime Semantic Segmentation Using Daytime Video and GPS data
Semantic segmentation for autonomous driving should be robust against various
in-the-wild environments. Nighttime semantic segmentation is especially
challenging due to a lack of annotated nighttime images and a large domain gap
from daytime images with sufficient annotation. In this paper, we propose a
novel GPS-based training framework for nighttime semantic segmentation. Given
GPS-aligned pairs of daytime and nighttime images, we perform cross-domain
correspondence matching to obtain pixel-level pseudo supervision. Moreover, we
conduct flow estimation between daytime video frames and apply GPS-based
scaling to acquire another pixel-level pseudo supervision. Using these pseudo
supervisions with a confidence map, we train a nighttime semantic segmentation
network without any annotation from nighttime images. Experimental results
demonstrate the effectiveness of the proposed method on several nighttime
semantic segmentation datasets. Our source code is available at
https://github.com/jimmy9704/GPS-GLASS.Comment: ICCVW 202
Batalin-Tyutin Quantization of the Chiral Schwinger Model
We quantize the chiral Schwinger Model by using the Batalin-Tyutin formalism.
We show that one can systematically construct the first class constraints and
the desired involutive Hamiltonian, which naturally generates all secondary
constraints. For , this Hamiltonian gives the gauge invariant Lagrangian
including the well-known Wess-Zumino terms, while for the corresponding
Lagrangian has the additional new type of the Wess-Zumino terms, which are
irrelevant to the gauge symmetry.Comment: 15 pages, latex, no figures, to be published in Z. Phys. C (1995
Two-Dimensional Dirac Fermions Protected by Space-Time Inversion Symmetry in Black Phosphorus
We report the realization of novel symmetry-protected Dirac fermions in a
surface-doped two-dimensional (2D) semiconductor, black phosphorus. The widely
tunable band gap of black phosphorus by the surface Stark effect is employed to
achieve a surprisingly large band inversion up to ~0.6 eV. High-resolution
angle-resolved photoemission spectra directly reveal the pair creation of Dirac
points and their moving along the axis of the glide-mirror symmetry. Unlike
graphene, the Dirac point of black phosphorus is stable, as protected by
spacetime inversion symmetry, even in the presence of spin-orbit coupling. Our
results establish black phosphorus in the inverted regime as a simple model
system of 2D symmetry-protected (topological) Dirac semimetals, offering an
unprecedented opportunity for the discovery of 2D Weyl semimetals
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