378 research outputs found
Layer Decomposition Learning Based on Gaussian Convolution Model and Residual Deblurring for Inverse Halftoning
Layer decomposition to separate an input image into base and detail layers
has been steadily used for image restoration. Existing residual networks based
on an additive model require residual layers with a small output range for fast
convergence and visual quality improvement. However, in inverse halftoning,
homogenous dot patterns hinder a small output range from the residual layers.
Therefore, a new layer decomposition network based on the Gaussian convolution
model (GCM) and structure-aware deblurring strategy is presented to achieve
residual learning for both the base and detail layers. For the base layer, a
new GCM-based residual subnetwork is presented. The GCM utilizes a statistical
distribution, in which the image difference between a blurred continuous-tone
image and a blurred halftoned image with a Gaussian filter can result in a
narrow output range. Subsequently, the GCM-based residual subnetwork uses a
Gaussian-filtered halftoned image as input and outputs the image difference as
residual, thereby generating the base layer, i.e., the Gaussian-blurred
continuous-tone image. For the detail layer, a new structure-aware residual
deblurring subnetwork (SARDS) is presented. To remove the Gaussian blurring of
the base layer, the SARDS uses the predicted base layer as input and outputs
the deblurred version. To more effectively restore image structures such as
lines and texts, a new image structure map predictor is incorporated into the
deblurring network to induce structure-adaptive learning. This paper provides a
method to realize the residual learning of both the base and detail layers
based on the GCM and SARDS. In addition, it is verified that the proposed
method surpasses state-of-the-art methods based on U-Net, direct deblurring
networks, and progressively residual networks
Heavy Rain Face Image Restoration: Integrating Physical Degradation Model and Facial Component Guided Adversarial Learning
With the recent increase in intelligent CCTVs for visual surveillance, a new
image degradation that integrates resolution conversion and synthetic rain
models is required. For example, in heavy rain, face images captured by CCTV
from a distance have significant deterioration in both visibility and
resolution. Unlike traditional image degradation models (IDM), such as rain
removal and superresolution, this study addresses a new IDM referred to as a
scale-aware heavy rain model and proposes a method for restoring
high-resolution face images (HR-FIs) from low-resolution heavy rain face images
(LRHR-FI). To this end, a 2-stage network is presented. The first stage
generates low-resolution face images (LR-FIs), from which heavy rain has been
removed from the LRHR-FIs to improve visibility. To realize this, an
interpretable IDM-based network is constructed to predict physical parameters,
such as rain streaks, transmission maps, and atmospheric light. In addition,
the image reconstruction loss is evaluated to enhance the estimates of the
physical parameters. For the second stage, which aims to reconstruct the HR-FIs
from the LR-FIs outputted in the first stage, facial component guided
adversarial learning (FCGAL) is applied to boost facial structure expressions.
To focus on informative facial features and reinforce the authenticity of
facial components, such as the eyes and nose, a face-parsing-guided generator
and facial local discriminators are designed for FCGAL. The experimental
results verify that the proposed approach based on physical-based network
design and FCGAL can remove heavy rain and increase the resolution and
visibility simultaneously. Moreover, the proposed heavy-rain face image
restoration outperforms state-of-the-art models of heavy rain removal,
image-to-image translation, and superresolution
Trap-Based Pest Counting: Multiscale and Deformable Attention CenterNet Integrating Internal LR and HR Joint Feature Learning
Pest counting, which predicts the number of pests in the early stage, is very
important because it enables rapid pest control, reduces damage to crops, and
improves productivity. In recent years, light traps have been increasingly used
to lure and photograph pests for pest counting. However, pest images have a
wide range of variability in pest appearance owing to severe occlusion, wide
pose variation, and even scale variation. This makes pest counting more
challenging. To address these issues, this study proposes a new pest counting
model referred to as multiscale and deformable attention CenterNet
(Mada-CenterNet) for internal low-resolution (LR) and high-resolution (HR)
joint feature learning. Compared with the conventional CenterNet, the proposed
Mada-CenterNet adopts a multiscale heatmap generation approach in a two-step
fashion to predict LR and HR heatmaps adaptively learned to scale variations,
that is, changes in the number of pests. In addition, to overcome the pose and
occlusion problems, a new between-hourglass skip connection based on deformable
and multiscale attention is designed to ensure internal LR and HR joint feature
learning and incorporate geometric deformation, thereby resulting in an
improved pest counting accuracy. Through experiments, the proposed
Mada-CenterNet is verified to generate the HR heatmap more accurately and
improve pest counting accuracy owing to multiscale heatmap generation, joint
internal feature learning, and deformable and multiscale attention. In
addition, the proposed model is confirmed to be effective in overcoming severe
occlusions and variations in pose and scale. The experimental results show that
the proposed model outperforms state-of-the-art crowd counting and object
detection models
PERFORMANCE EVALUATION OF HYBRID SOLAR AIRWATER HEATER WITH VARIOUS INLET AIR TEMPERATURE DURING HEATING PROCESS
Research about hybrid solar air-water heater that can heating both air and liquid has been conducted for enhancing the usage of solar thermal energy. In the previous study, thermal efficiency of this collector was investigated with many operating and external conditions, but all of previous experiment conducted using outdoor air as inlet air of collector. Thus, in this study, the performance change of hybrid solar air-water heater was investigated with change of inlet air temperature during air and liquid were heated simultaneously. As a result, thermal efficiency for liquid heating was increased with increment of the inlet air temperature. On the contrary to this, thermal efficiency for air heating of collector was decreased with increment of inlet air temperature. In case of total thermal efficiency of collector considered air and liquid heat gain, it was also decreased with increment of inlet air temperature. From these results, it was confirmed that using outdoor air directly as inlet air of collector is better for the use of solar energy. However it is hard to conclude that which is better between using outdoor air and heated air on the perspective of energy saving of building because heat storage performance was increased if the return air or any heated air is used as inlet air of hybrid solar air-water heater when air and liquid was heated simultaneously even air and total thermal efficiency is decreased. Thus, the necessity of more profound study and consideration about this as a further study was also confirmed
Design, Analysis and Empirical Researches for Solar Heat Collecting System based on Flat Mirrors Combination
There has been a dramatic increase of research on energy production using solar energy. This research aims to examine development of concentrating solar collector that is related to mid-high solar energy field. Although the use of dish type solar thermal system has been common in the existing high-efficiency collector technology, several problems have been raised. In order to solve these issues, the frame has been designed as flat plate type with Fresnel lens and the structural stability has been proved by analysis. Furthermore, the experiment that checks collectorrsquos temperature has been performed for the correct works of the stirling engine
Application of Artificial Neural Network to Search for Gravitational-Wave Signals Associated with Short Gamma-Ray Bursts
We apply a machine learning algorithm, the artificial neural network, to the
search for gravitational-wave signals associated with short gamma-ray bursts.
The multi-dimensional samples consisting of data corresponding to the
statistical and physical quantities from the coherent search pipeline are fed
into the artificial neural network to distinguish simulated gravitational-wave
signals from background noise artifacts. Our result shows that the data
classification efficiency at a fixed false alarm probability is improved by the
artificial neural network in comparison to the conventional detection
statistic. Therefore, this algorithm increases the distance at which a
gravitational-wave signal could be observed in coincidence with a gamma-ray
burst. In order to demonstrate the performance, we also evaluate a few seconds
of gravitational-wave data segment using the trained networks and obtain the
false alarm probability. We suggest that the artificial neural network can be a
complementary method to the conventional detection statistic for identifying
gravitational-wave signals related to the short gamma-ray bursts.Comment: 30 pages, 10 figure
In-Plane Strengthening of Unreinforced Masonry Walls by Glass Fiber-Reinforced Polyurea
Strengthening techniques have been employed in Korea to unreinforced masonry walls (UMWs) for several years to protect them from damage caused by the intermittent occurrence of earthquakes. Polyurea, which has a high tensile strength and elongation rate, can be utilized as a strengthening material to enhance the in-plane strength and ductility of UMWs. Glass fiber-reinforced polyurea (GFRPU) is a composite elastomer manufactured by progressively adding milled glass fiber to polyurea. The purpose of this study is to investigate the enhancement of the in-plane strength and ductility of UMWs using GFRPU, depending on the shape of the GFRPU coating on the wall. Four masonry wall specimens are tested with test variables of the number of strengthening sides and coating shapes. It is illustrated that the GFRPU reinforcement of masonry wall leads to enhanced load-carrying capacity, ductility, and energy absorption. An empirical formula to represent the degree of strengthening effected by GFRPU is proposed in this study. Doi: 10.28991/cej-2021-03091782 Full Text: PD
Out-of-Plane Strengthening of Unreinforced Masonry Walls by Glass Fiber-Reinforced Polyurea
Fiber-reinforced polymer reinforcement or polyurea reinforcement techniques are applied to strengthen unreinforced masonry walls (UMWs). The purpose of this experimental study is to verify the out-of-plane reinforcing effect of sprayed glass fiber-reinforced polyurea (GFRPU), which is a composite elastomer made of polyurea and milled glass fibers on UMW. The out-of-plane strengths and ductile behaviors based on various coating shapes are compared in this study. An empirical formula to describe the degree of reinforcement on the out-of-plane strength of the UMW is derived based on the experimental results. It is observed that the peak load-carrying capacity, ductility, and energy absorption capacity gradually improve with an increase in the strengthening degree or area. Compared with the existing masonry wall reinforcement method, the GFRPU technique is a construction method that can help improve the safety performance along with ease of construction and economic efficiency. Doi: 10.28991/CEJ-2022-08-01-011 Full Text: PD
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