TY - JOUR
T1 - Disaster debris estimation using high-resolution polarimetric stereo-SAR
AU - Koyama, Christian N.
AU - Gokon, Hideomi
AU - Jimbo, Masaru
AU - Koshimura, Shunichi
AU - Sato, Motoyuki
N1 - Funding Information:
We gratefully acknowledge the financial support by JSPS Grant-in-Aid for Scientific Research (A) 23246076 . We are most thankful to the National Institute for Communication and Information Technology (NICT) for the cooperation and provision of Pi-SAR2 image data through the PI program for collaborative research. Our special thanks go to Dr. Tatsuharu Kobayashi and Dr. Shoichiro Kojima of NICT as well as to the anonymous reviewers who helped improving this paper. We also thank the numerous Tohoku University students of Koshimura Lab and Sato Lab for the vital support in the ground measurements and the Sendai city authorities and subcontractors for their cooperation.
Publisher Copyright:
© 2016 The Author(s)
PY - 2016/10/1
Y1 - 2016/10/1
N2 - This paper addresses the problem of debris estimation which is one of the most important initial challenges in the wake of a disaster like the Great East Japan Earthquake and Tsunami. Reasonable estimates of the debris have to be made available to decision makers as quickly as possible. Current approaches to obtain this information are far from being optimal as they usually rely on manual interpretation of optical imagery. We have developed a novel approach for the estimation of tsunami debris pile heights and volumes for improved emergency response. The method is based on a stereo-synthetic aperture radar (stereo-SAR) approach for very high-resolution polarimetric SAR. An advanced gradient-based optical-flow estimation technique is applied for optimal image coregistration of the low-coherence non-interferometric data resulting from the illumination from opposite directions and in different polarizations. By applying model based decomposition of the coherency matrix, only the odd bounce scattering contributions are used to optimize echo time computation. The method exclusively considers the relative height differences from the top of the piles to their base to achieve a very fine resolution in height estimation. To define the base, a reference point on non-debris-covered ground surface is located adjacent to the debris pile targets by exploiting the polarimetric scattering information. The proposed technique is validated using in situ data of real tsunami debris taken on a temporary debris management site in the tsunami affected area near Sendai city, Japan. The estimated height error is smaller than 0.6 m RMSE. The good quality of derived pile heights allows for a voxel-based estimation of debris volumes with a RMSE of 1099 m3. Advantages of the proposed method are fast computation time, and robust height and volume estimation of debris piles without the need for pre-event data or auxiliary information like DEM, topographic maps or GCPs.
AB - This paper addresses the problem of debris estimation which is one of the most important initial challenges in the wake of a disaster like the Great East Japan Earthquake and Tsunami. Reasonable estimates of the debris have to be made available to decision makers as quickly as possible. Current approaches to obtain this information are far from being optimal as they usually rely on manual interpretation of optical imagery. We have developed a novel approach for the estimation of tsunami debris pile heights and volumes for improved emergency response. The method is based on a stereo-synthetic aperture radar (stereo-SAR) approach for very high-resolution polarimetric SAR. An advanced gradient-based optical-flow estimation technique is applied for optimal image coregistration of the low-coherence non-interferometric data resulting from the illumination from opposite directions and in different polarizations. By applying model based decomposition of the coherency matrix, only the odd bounce scattering contributions are used to optimize echo time computation. The method exclusively considers the relative height differences from the top of the piles to their base to achieve a very fine resolution in height estimation. To define the base, a reference point on non-debris-covered ground surface is located adjacent to the debris pile targets by exploiting the polarimetric scattering information. The proposed technique is validated using in situ data of real tsunami debris taken on a temporary debris management site in the tsunami affected area near Sendai city, Japan. The estimated height error is smaller than 0.6 m RMSE. The good quality of derived pile heights allows for a voxel-based estimation of debris volumes with a RMSE of 1099 m3. Advantages of the proposed method are fast computation time, and robust height and volume estimation of debris piles without the need for pre-event data or auxiliary information like DEM, topographic maps or GCPs.
KW - Debris
KW - Disaster mitigation
KW - Radar polarimetry
KW - Radargrammetry
KW - Synthetic aperture radar (SAR)
KW - Tsunami
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U2 - 10.1016/j.isprsjprs.2016.08.003
DO - 10.1016/j.isprsjprs.2016.08.003
M3 - Article
AN - SCOPUS:84987936701
VL - 120
SP - 84
EP - 98
JO - ISPRS Journal of Photogrammetry and Remote Sensing
JF - ISPRS Journal of Photogrammetry and Remote Sensing
SN - 0924-2716
ER -