scholarly journals An Automated Technique for Damage Mapping after Earthquakes by Detecting Changes between High-Resolution Images

2018 ◽  
Author(s):  
Tianyu Ci ◽  
Zhen Liu ◽  
Ying Wang ◽  
Qigen Lin ◽  
Di Wu
Keyword(s):  
High Resolution ◽  
Disaster Response ◽  
Similarity Index ◽  
Optical Data ◽  
Disaster Loss ◽  
Optical Images ◽  
High Resolution Images ◽  
Automated Technique ◽  
Damage Mapping ◽  
Collapsed Buildings

Abstract. Improving the speed and accuracy of earthquake disaster loss evaluations is very important for disaster response and rescue. This paper presents a new method for urban damage assessments after earthquake disasters by using a change detection technique between bi-temporal (pre- and post-event) high-resolution optical images. A similarity index derived from a pair of images was used to extract the characteristics of collapsed buildings. In this paper, the methods are illustrated using two case studies. Our results confirmed the effectiveness and precision of the proposed technique with optical data of the damage presented using a block scale.

scholarly journals SAR AND OBLIQUE AERIAL OPTICAL IMAGE FUSION FOR URBAN AREA IMAGE SEGMENTATION

2017 ◽  
Vol XLII-1/W1 ◽  
pp. 639-642 ◽  
Author(s):  
J. Fagir ◽  
A. Schubert ◽  
M. Frioud ◽  
D. Henke
Keyword(s):  
Image Segmentation ◽  
High Resolution ◽  
Single Channel ◽  
Research Area ◽  
Synthetic Aperture ◽  
Optical Data ◽  
Surface Model ◽  
Digital Surface Model ◽  
Oblique View ◽  
Optical Images

The fusion of synthetic aperture radar (SAR) and optical data is a dynamic research area, but image segmentation is rarely treated. While a few studies use low-resolution nadir-view optical images, we approached the segmentation of SAR and optical images acquired from the same airborne platform – leading to an oblique view with high resolution and thus increased complexity. To overcome the geometric differences, we generated a digital surface model (DSM) from adjacent optical images and used it to project both the DSM and SAR data into the optical camera frame, followed by segmentation with each channel. The fused segmentation algorithm was found to out-perform the single-channel version.

scholarly journals Towards Operational Satellite-Based Damage-Mapping Using U-Net Convolutional Network: A Case Study of 2011 Tohoku Earthquake-Tsunami

2018 ◽  
Vol 10 (10) ◽  
pp. 1626 ◽  
Author(s):  
Yanbing Bai ◽  
Erick Mas ◽  
Shunichi Koshimura
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Disaster Response ◽  
Tohoku Earthquake ◽  
2011 Tohoku Earthquake ◽  
Mapping Technique ◽  
Convolutional Network ◽  
Response Practice ◽  
Damage Mapping

The satellite remote-sensing-based damage-mapping technique has played an indispensable role in rapid disaster response practice, whereas the current disaster response practice remains subject to the low damage assessment accuracy and lag in timeliness, which dramatically reduces the significance and feasibility of extending the present method to practical operational applications. Therefore, a highly efficient and intelligent remote-sensing image-processing framework is urgently required to mitigate these challenges. In this article, a deep learning algorithm for the semantic segmentation of high-resolution remote-sensing images using the U-net convolutional network was proposed to map the damage rapidly. The algorithm was implemented within a Microsoft Cognitive Toolkit framework in the GeoAI platform provided by Microsoft. The study takes the 2011 Tohoku Earthquake-Tsunami as a case study, for which the pre- and post-disaster high-resolution WorldView-2 image is used. The performance of the proposed U-net model is compared with that of deep residual U-net. The comparison highlights the superiority U-net for tsunami damage mapping in this work. Our proposed method achieves the overall accuracy of 70.9% in classifying the damage into “washed away,” “collapsed,” and “survived” at the pixel level. In future disaster scenarios, our proposed model can generate the damage map in approximately 2–15 min when the preprocessed remote-sensing datasets are available. Our proposed damage-mapping framework has significantly improved the application value in operational disaster response practice by substantially reducing the manual operation steps required in the actual disaster response. Besides, the proposed framework is highly flexible to extend to other scenarios and various disaster types, which can accelerate operational disaster response practice.

scholarly journals Post-War Urban Damage Mapping Using InSAR: The Case of Mosul City in Iraq

2021 ◽  
Vol 10 (3) ◽  
pp. 140
Author(s):  
Ali Darvishi Boloorani ◽  
Mehdi Darvishi ◽  
Qihao Weng ◽  
Xiangtong Liu
Keyword(s):  
High Resolution ◽  
Urban Areas ◽  
Human Life ◽  
Islamic State ◽  
Persistent Scatterer Interferometry ◽  
Optical Images ◽  
Collateral Effects ◽  
Sar Data ◽  
Post War ◽  
Damage Mapping

Urban infrastructures have become imperative to human life. Any damage to these infrastructures as a result of detrimental activities would accrue huge economical costs and severe casualties. War in particular is a major anthropogenic calamity with immense collateral effects on the social and economic fabric of human nations. Therefore, damaged buildings assessment plays a prominent role in post-war resettlement and reconstruction of urban infrastructures. The data-analysis process of this assessment is essential to any post-disaster program and can be carried out via different formats. Synthetic Aperture Radar (SAR) data and Interferometric SAR (InSAR) techniques help us to establish a reliable and fast monitoring system for detecting post-war damages in urban areas. Along this thread, the present study aims to investigate the feasibility and mode of implementation of Sentinel-1 SAR data and InSAR techniques to estimate post-war damage in war-affected areas as opposed to using commercial high-resolution optical images. The study is presented in the form of a survey to identify urban areas damaged or destroyed by war (Islamic State of Iraq and the Levant, ISIL, or ISIS occupation) in the city of Mosul, Iraq, using Sentinel-1 (S1) data over the 2014–2017 period. Small BAseline Subset (SBAS), Persistent Scatterer Interferometry (PSI) and coherent-intensity-based analysis were also used to identify war-damaged buildings. Accuracy assessments for the proposed SAR-based mapping approach were conducted by comparing the destruction map to the available post-war destruction map of United Nations Institute for Training and Research (UNITAR); previously developed using optical very high-resolution images, drone imagery, and field visits. As the findings suggest, 40% of the entire city, the western sectors, especially the Old City, were affected most by ISIS war. The findings are also indicative of the efficiency of incorporating Sentinel-1 SAR data and InSAR technique to map post-war urban damages in Mosul. The proposed method could be widely used as a tool in damage assessment procedures in any post-war reconstruction programs.

ACCURATE EVALUATION OF BUILDING DAMAGE IN THE 2003 BOUMERDES, ALGERIA EARTHQUAKE FROM QUICKBIRD SATELLITE IMAGES

2011 ◽  
Vol 05 (01) ◽  
pp. 1-18 ◽  
Author(s):  
ABDELGHANI MESLEM ◽  
FUMIO YAMAZAKI ◽  
YOSHIHISA MARUYAMA
Keyword(s):  
High Resolution ◽  
Satellite Images ◽  
Ground Truth ◽  
Building Damage ◽  
Geographical Information ◽  
Ground Truth Data ◽  
Damage Level ◽  
Damage Grade ◽  
Damage Mapping ◽  
Collapsed Buildings

Using QuickBird satellite images of Boumerdes city obtained following the 21 May 2003 Algeria earthquake, our study examined the applicability of high-resolution optical imagery for the visual detection of building damage grade based on the ground-truth data on the urban nature, typology of a total of 2,794 buildings, and the real damage observed. The results are presented as geographical information system (GIS) damage mapping of buildings obtained from field surveys and QuickBird images. In general, totally collapsed buildings, partially collapsed buildings, and buildings surrounded by debris can be identified by using only post-event pan-sharpened images. However, due to the nature of the damage observed, some buildings may be judged incorrectly even if preevent images are employed as a reference to evaluate the damage status. Hence, in this study, we clarify the limitations regarding the applicability of high-resolution optical satellite imagery in building damage-level mapping.

scholarly journals Ship Wakes in Optical Images

2018 ◽  
Vol 35 (8) ◽  
pp. 1633-1648 ◽  
Author(s):  
Yingfei Liu ◽  
Ruru Deng
Keyword(s):  
High Resolution ◽  
Internal Waves ◽  
Fishing Vessels ◽  
Turbulent Wakes ◽  
Optical Images ◽  
Different Types ◽  
Ship Wakes ◽  
High Resolution Images ◽  
Formation Conditions

AbstractShip wakes are more distinct than the hulls and can be visually observed in optical images. In this paper the wakes of 2836 ships in 32 optical images with different resolutions are observed and summarized. The ships are divided into four types according to the hull and wake features: fishing vessels, motorboats, cargo ships, and warships. The results show that each ship type has characteristic wakes, and there are significant differences among the categories. The probabilities of occurrence of different types of wakes and their components are shown. Turbulent wakes are inevitable. The probability of occurrence of Kelvin wakes is small and less than 40%. The visibilities of internal waves that are generated by only cargo ships are very low as a result of the harsh formation conditions. Turbulent wakes should be preferentially detected. Low-resolution images are more suitable for the detection and positioning of hulls and wakes, while high-resolution images with more details are convenient for further analysis of the size, velocity, and draft of ships. The study on the cause of the formation of the features of ship wakes in optical images proves that the classification of the wakes is reasonable and that the features of wakes can be used to initially identify the type of ship.

FeXIV Line Emission Polarization of the July 11, 1991 Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 541-547
Author(s):  
J. Sýkora ◽  
J. Rybák ◽  
P. Ambrož
Keyword(s):  
High Resolution ◽  
Solar Corona ◽  
Emission Line ◽  
Solar Eclipse ◽  
White Light ◽  
Preliminary Analysis ◽  
Line Emission ◽  
Total Solar Eclipse ◽  
Degree Of Polarization ◽  
High Resolution Images

AbstractHigh resolution images, obtained during July 11, 1991 total solar eclipse, allowed us to estimate the degree of solar corona polarization in the light of FeXIV 530.3 nm emission line and in the white light, as well. Very preliminary analysis reveals remarkable differences in the degree of polarization for both sets of data, particularly as for level of polarization and its distribution around the Sun’s limb.

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