29 research outputs found
PE-YOLO: Pyramid Enhancement Network for Dark Object Detection
Current object detection models have achieved good results on many benchmark
datasets, detecting objects in dark conditions remains a large challenge. To
address this issue, we propose a pyramid enhanced network (PENet) and joint it
with YOLOv3 to build a dark object detection framework named PE-YOLO. Firstly,
PENet decomposes the image into four components of different resolutions using
the Laplacian pyramid. Specifically we propose a detail processing module (DPM)
to enhance the detail of images, which consists of context branch and edge
branch. In addition, we propose a low-frequency enhancement filter (LEF) to
capture low-frequency semantics and prevent high-frequency noise. PE-YOLO
adopts an end-to-end joint training approach and only uses normal detection
loss to simplify the training process. We conduct experiments on the low-light
object detection dataset ExDark to demonstrate the effectiveness of ours. The
results indicate that compared with other dark detectors and low-light
enhancement models, PE-YOLO achieves the advanced results, achieving 78.0% in
mAP and 53.6 in FPS, respectively, which can adapt to object detection under
different low-light conditions. The code is available at
https://github.com/XiangchenYin/PE-YOLO.Comment: Accepted at ICANN 202
DEFormer: DCT-driven Enhancement Transformer for Low-light Image and Dark Vision
The goal of low-light image enhancement is to restore the color and details
of the image and is of great significance for high-level visual tasks in
autonomous driving. However, it is difficult to restore the lost details in the
dark area by relying only on the RGB domain. In this paper we introduce
frequency as a new clue into the network and propose a novel DCT-driven
enhancement transformer (DEFormer). First, we propose a learnable frequency
branch (LFB) for frequency enhancement contains DCT processing and
curvature-based frequency enhancement (CFE). CFE calculates the curvature of
each channel to represent the detail richness of different frequency bands,
then we divides the frequency features, which focuses on frequency bands with
richer textures. In addition, we propose a cross domain fusion (CDF) for
reducing the differences between the RGB domain and the frequency domain. We
also adopt DEFormer as a preprocessing in dark detection, DEFormer effectively
improves the performance of the detector, bringing 2.1% and 3.4% improvement in
ExDark and DARK FACE datasets on mAP respectively.Comment: submit to ICRA202
Near-infrared Hong-Ou-Mandel interference on a silicon quantum photonic circuit
Near-infrared Hong-Ou-Mandel quantum interference is observed in silicon
nanophotonic directional couplers with raw visibilities on-chip at 90.5%.
Spectrally-bright 1557-nm two-photon states are generated in a
periodically-poled KTiOPO4 waveguide chip, serving as the entangled photon
source and pumped with a self-injection locked laser, for the photon
statistical measurements. Efficient four-port coupling in the communications
C-band and in the high-index-contrast silicon photonics platform is
demonstrated, with matching theoretical predictions of the quantum interference
visibility. Constituents for the residual quantum visibility imperfection are
examined, supported with theoretical analysis of the sequentially-triggered
multipair biphoton contribution and techniques for visibility compensation,
towards scalable high-bitrate quantum information processing and
communications.Comment: 15 pages, 6 figure
Scalable Production of High-Quality Silver Nanowires via Continuous-Flow Droplet Synthesis
Silver nanowires (Ag NWs) have shown great potential in next-generation flexible displays, due to their superior electronic, optical, and mechanical properties. However, as with most nanomaterials, a limited production capacity and poor reproduction quality, based on the batch reaction, largely hinder their application. Here, we applied continuous-flow synthesis for the scalable and high-quality production of Ag NWs, and built a pilot-scale line for kilogram-level per day production. In addition, we found that trace quantities of water could generate sufficient vapor as a spacer under high temperature to efficiently prevent the back-flow or mixed-flow of the reaction solution. With an optimized synthetic formula, a mass production of pure Ag NWs of 36.5 g/h was achieved by a multiple-channel, continuous-flow reactor
GW26-e1438 Ginsenoside Rb1 Reverses Human Umbilical Vein Endothelial Cells Senescence Induced by Hydrogen Peroxide
Thermal Lithiated-TiO<sub>2</sub>: A Robust and Electron-Conducting Protection Layer for Li–Si Alloy Anode
Developing new electrode
materials with high capacity and stability
is an urgent demand in electric vehicle applications. Li<sub><i>x</i></sub>Si alloy, as a promising high-capacity and Li-containing
anode candidate, has attracted much attention. However, the alloy
anode suffers severely from intrinsic high chemical reactivity and
poor cycling stability in battery fabrication and operation. Here,
we have developed a facile coating-then-lithiation approach to prepare
lithiated-TiO<sub>2</sub> protected Li<sub><i>x</i></sub>Si nanoparticles (Li<sub><i>x</i></sub>Si–Li<sub>2</sub>O/Ti<sub><i>y</i></sub>O<sub><i>z</i></sub> NPs) as an attractive anode material. The robust lithiated-TiO<sub>2</sub> protection matrix not only provides fast electron transport
pathways to efficiently improve the electrical conductivity between
Li<sub><i>x</i></sub>Si/Si NPs, but also spatially limits
the direct solid electrolyte interphase formation on Li<sub><i>x</i></sub>Si/Si cores during cycling. More importantly, this
dense coating layer protects most inner Li<sub><i>x</i></sub>Si alloys from ambient corrosion, leading to high dry-air stability.
As a result, the resulting Li<sub><i>x</i></sub>Si–Li<sub>2</sub>O/Ti<sub><i>y</i></sub>O<sub><i>z</i></sub> anode achieves greatly enhanced cycling and chemical stability in
half-cells. It maintains capacity of about 1300 mAh g<sup>–1</sup> after prolonged 500 cycles at a high current rate of C/2, with 77%
capacity retention. In addition, it exhibits excellent dry-air stability,
with around 87% capacity retained after exposure to dry air (10% relative
humidity) for 30 days
GW26-e1434 Ginsenoside Rb1 prolongs the lifespan and protect against brain aging in C57BL/6J mice
Assembly and Photonic Properties of Superparamagnetic Colloids in Complex Magnetic Fields
Interparticle magnetic dipole force has been found to drive the formation of dynamic superparamagnetic colloidal particle chains that can lead to the creation of photonic nanostructures with rapidly and reversibly tunable structural colors in the visible and near-infrared spectrum. Although most studies on magnetic assembly utilize simple permanent magnets or electromagnets, magnetic fields, in principle, can be more complex, allowing the localized modulation of assembly and subsequent creation of complex superstructures. To explore the potential applications of a magnetically tunable photonic system, we study the assembly of magnetic colloidal particles in the complex magnetic field produced by a nonideal linear Halbach array. We demonstrate that a horizontal magnetic field sandwiched between two vertical fields would allow one to change the orientation of the particle chains, producing a high contrast in color patterns. A phase transition of Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub> particles from linear particle chains to three-dimensional crystals is found to be determined by the interplay of the magnetic dipole force and packing force, as well as the strong electrostatic force. While a color pattern with tunable structures and diffractions can be instantly created when the particles are assembled in the form of linear chains in the regions with vertical fields, the large field gradient in the horizontal orientation may destabilize the chain structures and produces a pattern of 3D crystals that compliments that of initial chain assemblies. Our study not only demonstrates the great potential of magnetically responsive photonic structures in the visual graphic applications such as signage and security documents but also points out the potential challenge in pattern stability when the particle assemblies are subjected to complex magnetic fields that often involve large field gradients