1,013 research outputs found
Dialectical GAN for SAR Image Translation: From Sentinel-1 to TerraSAR-X
Contrary to optical images, Synthetic Aperture Radar (SAR) images are in
different electromagnetic spectrum where the human visual system is not
accustomed to. Thus, with more and more SAR applications, the demand for
enhanced high-quality SAR images has increased considerably. However,
high-quality SAR images entail high costs due to the limitations of current SAR
devices and their image processing resources. To improve the quality of SAR
images and to reduce the costs of their generation, we propose a Dialectical
Generative Adversarial Network (Dialectical GAN) to generate high-quality SAR
images. This method is based on the analysis of hierarchical SAR information
and the "dialectical" structure of GAN frameworks. As a demonstration, a
typical example will be shown where a low-resolution SAR image (e.g., a
Sentinel-1 image) with large ground coverage is translated into a
high-resolution SAR image (e.g., a TerraSAR-X image). Three traditional
algorithms are compared, and a new algorithm is proposed based on a network
framework by combining conditional WGAN-GP (Wasserstein Generative Adversarial
Network - Gradient Penalty) loss functions and Spatial Gram matrices under the
rule of dialectics. Experimental results show that the SAR image translation
works very well when we compare the results of our proposed method with the
selected traditional methods.Comment: 22 pages, 15 figure
SRDA-Net: Super-Resolution Domain Adaptation Networks for Semantic Segmentation
Recently, Unsupervised Domain Adaptation was proposed to address the domain
shift problem in semantic segmentation task, but it may perform poor when
source and target domains belong to different resolutions. In this work, we
design a novel end-to-end semantic segmentation network, Super-Resolution
Domain Adaptation Network (SRDA-Net), which could simultaneously complete
super-resolution and domain adaptation. Such characteristics exactly meet the
requirement of semantic segmentation for remote sensing images which usually
involve various resolutions. Generally, SRDA-Net includes three deep neural
networks: a Super-Resolution and Segmentation (SRS) model focuses on recovering
high-resolution image and predicting segmentation map; a pixel-level domain
classifier (PDC) tries to distinguish the images from which domains; and
output-space domain classifier (ODC) discriminates pixel label distributions
from which domains. PDC and ODC are considered as the discriminators, and SRS
is treated as the generator. By the adversarial learning, SRS tries to align
the source with target domains on pixel-level visual appearance and
output-space. Experiments are conducted on the two remote sensing datasets with
different resolutions. SRDA-Net performs favorably against the state-of-the-art
methods in terms of accuracy and visual quality. Code and models are available
at https://github.com/tangzhenjie/SRDA-Net
SEG-ESRGAN: A multi-task network for super-resolution and semantic segmentation of remote sensing images
The production of highly accurate land cover maps is one of the primary challenges in remote sensing, which depends on the spatial resolution of the input images. Sometimes, high-resolution imagery is not available or is too expensive to cover large areas or to perform multitemporal analysis. In this context, we propose a multi-task network to take advantage of the freely available Sentinel-2 imagery to produce a super-resolution image, with a scaling factor of 5, and the corresponding high-resolution land cover map. Our proposal, named SEG-ESRGAN, consists of two branches: the super-resolution branch, that produces Sentinel-2 multispectral images at 2 m resolution, and an encoder–decoder architecture for the semantic segmentation branch, that generates the enhanced land cover map. From the super-resolution branch, several skip connections are retrieved and concatenated with features from the different stages of the encoder part of the segmentation branch, promoting the flow of meaningful information to boost the accuracy in the segmentation task. Our model is trained with a multi-loss approach using a novel dataset to train and test the super-resolution stage, which is developed from Sentinel-2 and WorldView-2 image pairs. In addition, we generated a dataset with ground-truth labels for the segmentation task. To assess the super-resolution improvement, the PSNR, SSIM, ERGAS, and SAM metrics were considered, while to measure the classification performance, we used the IoU, confusion matrix and the F1-score. Experimental results demonstrate that the SEG-ESRGAN model outperforms different full segmentation and dual network models (U-Net, DeepLabV3+, HRNet and Dual_DeepLab), allowing the generation of high-resolution land cover maps in challenging scenarios using Sentinel-2 10 m bands.This work was funded by the Spanish Agencia Estatal de Investigación (AEI) under projects ARTEMISAT-2 (CTM 2016-77733-R), PID2020-117142GB-I00 and PID2020-116907RB-I00 (MCIN/AEI call 10.13039/501100011033). L.S. would like to acknowledge the BECAL (Becas Carlos
Antonio López) scholarship for the financial support.Peer ReviewedPostprint (published version
Manipulation and generation of synthetic satellite images using deep learning models
Generation and manipulation of digital images based on deep learning (DL) are receiving increasing attention for both benign and malevolent uses. As the importance of satellite imagery is increasing, DL has started being used also for the generation of synthetic satellite images. However, the direct use of techniques developed for computer vision applications is not possible, due to the different nature of satellite images. The goal of our work is to describe a number of methods to generate manipulated and synthetic satellite images. To be specific, we focus on two different types of manipulations: full image modification and local splicing. In the former case, we rely on generative adversarial networks commonly used for style transfer applications, adapting them to implement two different kinds of transfer: (i) land cover transfer, aiming at modifying the image content from vegetation to barren and vice versa and (ii) season transfer, aiming at modifying the image content from winter to summer and vice versa. With regard to local splicing, we present two different architectures. The first one uses image generative pretrained transformer and is trained on pixel sequences in order to predict pixels in semantically consistent regions identified using watershed segmentation. The second technique uses a vision transformer operating on image patches rather than on a pixel by pixel basis. We use the trained vision transformer to generate synthetic image segments and splice them into a selected region of the to-be-manipulated image. All the proposed methods generate highly realistic, synthetic, and satellite images. Among the possible applications of the proposed techniques, we mention the generation of proper datasets for the evaluation and training of tools for the analysis of satellite images. (c) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI
A dual network for super-resolution and semantic segmentation of sentinel-2 imagery
There is a growing interest in the development of automated data processing workflows that provide reliable, high spatial resolution land cover maps. However, high-resolution remote sensing images are not always affordable. Taking into account the free availability of Sentinel-2 satellite data, in this work we propose a deep learning model to generate high-resolution segmentation maps from low-resolution inputs in a multi-task approach. Our proposal is a dual-network model with two branches: the Single Image Super-Resolution branch, that reconstructs a high-resolution version of the input image, and the Semantic Segmentation Super-Resolution branch, that predicts a high-resolution segmentation map with a scaling factor of 2. We performed several experiments to find the best architecture, training and testing on a subset of the S2GLC 2017 dataset. We based our model on the DeepLabV3+ architecture, enhancing the model and achieving an improvement of 5% on IoU and almost 10% on the recall score. Furthermore, our qualitative results demonstrate the effectiveness and usefulness of the proposed approach.This work has been supported by the Spanish Research Agency (AEI) under project PID2020-117142GB-I00 of the call MCIN/AEI/10.13039/501100011033. L.S. would like to acknowledge the BECAL (Becas Carlos Antonio López) scholarship for the financial support.Peer ReviewedPostprint (published version
Deep learning methods applied to digital elevation models: state of the art
Deep Learning (DL) has a wide variety of applications in various
thematic domains, including spatial information. Although with
limitations, it is also starting to be considered in operations
related to Digital Elevation Models (DEMs). This study aims to
review the methods of DL applied in the field of altimetric spatial
information in general, and DEMs in particular. Void Filling (VF),
Super-Resolution (SR), landform classification and hydrography
extraction are just some of the operations where traditional methods
are being replaced by DL methods. Our review concludes
that although these methods have great potential, there are
aspects that need to be improved. More appropriate terrain information
or algorithm parameterisation are some of the challenges
that this methodology still needs to face.Functional Quality of Digital Elevation Models in Engineering’ of the State Agency Research of SpainPID2019-106195RB- I00/AEI/10.13039/50110001103
SAR-to-Optical Image Translation via Thermodynamics-inspired Network
Synthetic aperture radar (SAR) is prevalent in the remote sensing field but
is difficult to interpret in human visual perception. Recently, SAR-to-optical
(S2O) image conversion methods have provided a prospective solution for
interpretation. However, since there is a huge domain difference between
optical and SAR images, they suffer from low image quality and geometric
distortion in the produced optical images. Motivated by the analogy between
pixels during the S2O image translation and molecules in a heat field,
Thermodynamics-inspired Network for SAR-to-Optical Image Translation (S2O-TDN)
is proposed in this paper. Specifically, we design a Third-order Finite
Difference (TFD) residual structure in light of the TFD equation of
thermodynamics, which allows us to efficiently extract inter-domain invariant
features and facilitate the learning of the nonlinear translation mapping. In
addition, we exploit the first law of thermodynamics (FLT) to devise an
FLT-guided branch that promotes the state transition of the feature values from
the unstable diffusion state to the stable one, aiming to regularize the
feature diffusion and preserve image structures during S2O image translation.
S2O-TDN follows an explicit design principle derived from thermodynamic theory
and enjoys the advantage of explainability. Experiments on the public SEN1-2
dataset show the advantages of the proposed S2O-TDN over the current methods
with more delicate textures and higher quantitative results
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