Using multi-temporal remote sensor imagery to detect earthquake-triggered landslides     

Xiaojun Yang  Liding Chen 《International Journal of Applied Earth Observation and Geoinformation》2010

Landslides are a major type of geohazards claiming thousands of casualties and billions of dollars in property damages every year. Catastrophic landslide activities are often triggered by some extreme events such as earthquakes, excessive precipitations, or volcanic eruptions. Quickly identifying the spatial distribution of landslides induced by these extreme events is crucial for coordinating rescue efforts and planning in situ investigations. In this study, we propose an automated method for detecting the spatial distribution of earthquake-triggered landslides by examining after-event vegetation changes. Central to this method is the use of pre- and post-event remote sensor images covering the same area. Geometric correction and radiometric normalization are performed before deriving a vegetation index from each image. Then, an image differencing procedure is applied to the two derived indices. With the resultant difference image, an initial landslide distribution map is generated by highlighting the pixels with a threshold percentage decrease in the brightness values as a direct result of the image subtraction. The threshold percentage value is interactively determined by using a visual interpretation method. The final landslide distribution map is produced after using a modal filter to suppress boundary errors in the initial map. This method has been implemented in a test site, approximately 30 km from the epicenter of the Sichuan earthquake (7.9 Ms) that struck on 12 May 2008. A pre-event Thematic Mapper image and a post-event Advanced Spaceborne Thermal Emission and Reflection Radiometer scene are used. The thematic accuracy assessment indicates that 90% of the landslides have correctly been mapped. Given the relatively simple procedures and the good mapping accuracy, the image processing and change detection method identified in this study seems to be promising from an operational perspective.  相似文献   

用近场余震观测资料研究张北地震的发震构造   总被引：3，自引：3，他引：0       下载免费PDF全文

赖晓玲  刁桂苓  孙译 《地球物理学进展》2007,22(1):63-67

本文对张北近场地震资料进行了重新定位,并通过网格化处理得到震源空间分布图像、发震时间图像和定位残差图像.震源空间分布图像和发震时间图像细致地显示了极震区周围的发震构造时空特征为明显的北西方向,另外还存在断续的北东向特征.该震区在中新生代以来有过多期岩浆活动,极震区米家沟附近有一个火山口并且地壳内存在低速带和深断裂,复杂的地壳构造为孕震提供了必要的深部环境.  相似文献   

一种面向对象的TM影像的居民地提取方法   总被引：1，自引：0，他引：1  

朱满  龚浩  于之峰  葛春青 《测绘信息与工程》2009,34(4):36-38

提出了一种面向对象的TM影像的居民地提取方法,利用对象的光谱信息及其几何特征和空间信息识别居民地,实现了TM影像的居民地提取,结果表明这一方法效果很好。  相似文献   

HJ-1卫星数据质量及其在土地利用中的应用研究   总被引：1，自引：0，他引：1  

易玲  汪潇  刘斌 《国土资源遥感》2009,(3):74-77

通过对影像日视质量、光谱特性、噪声特征和几何纠正精度的分析,研究了HJ-1小卫星的数据质量;选择特征变量,优化训练样本,建立了分类模板,构建最大似然、最小距离和马氏距离3种分类器,对研究区域进行土地利用计算机自动分类,并对分类精度进行评价,研究了小卫星影像的土地利用分类精度.结果表明,HJ-1卫星数据质量较好,土地利用分类精度较高,可以在土地利用研究领域成为遥感数据更新的主体.  相似文献   

小波变换改进的MASK匀光算法   总被引：2，自引：1，他引：1  

张振  朱宝山  朱述龙  曹闻 《遥感学报》2009,13(6):1078-1086

针对单幅遥感影像内部所产生的亮度不均匀现象, 提出了一种基于小波变换改进的MASK匀光算法。该方法在利用小波变换获得不均匀背景图像的过程中, 对小波系数进行了自适应非线性改进, 克服了直接利用分块取均值获取背景影像的不足, 试验表明该算法能够较好地解决单幅遥感图像中亮度不均匀的现象, 具有较强的实用性。  相似文献   

Determination of internal wave properties from X-Band radar observations   总被引：2，自引：0，他引：2  

Rafael J. Ramos  Björn Lund  Hans C. Graber 《Ocean Engineering》2009,36(14):1039-1047

The application of nautical X-Band radars to measure internal wave (IW) properties is investigated. A methodology based on the use of Radon transform (RT) techniques to detect internal wave related features from backscatter image sequences is introduced to compute properties such as direction of propagation, non-linear velocity (c₀), distance between solitons (L_cc) and number of solitons per packet. The proposed methodology was applied to several events recorded by a ship-mounted X-Band radar system (WaMoS) during the NLIWI experiment in 2006. Results from the comparisons to simultaneous measurements taken at neighboring oceanographic moorings indicated that c₀ can be estimated with a RMS error of 0.06 m s⁻¹, which corresponds to a mean relative error of −1.4%. Similarly, L_cc can be estimated with a RMS error of 98 m, which is associated with a mean relative error of 14.6%. This latter error estimate however is likely to be overestimated, because it reflects strongly the separation between sampling stations as L_cc was shown to be highly dependent on propagation distance. The accuracy of the results shows that X-Band systems are well suited to measure internal wave properties offering some advantages over SAR and other in situ devices.  相似文献   

Experiments on vision guided docking of an autonomous underwater vehicle using one camera   总被引：1，自引：0，他引：1  

Jin-Yeong Park  Bong-huan Jun  Junho Oh 《Ocean Engineering》2009,36(1):48-61

This paper introduces an underwater docking procedure for the test-bed autonomous underwater vehicle (AUV) platform called ISiMI using one charge-coupled device (CCD) camera. The AUV is optically guided by lights mounted around the entrance of a docking station and a vision system consisting of a CCD camera and a frame grabber in the AUV. This paper presents an image processing procedure to identify the dock by discriminating between light images, and proposes a final approach algorithm based on the vision guidance. A signal processing technique to remove noise on the defused grabbed light images is introduced, and a two-stage final approach for stable docking at the terminal instant is suggested. A vision-guidance controller was designed with conventional PID controllers for the vertical plane and the horizontal plane. Experiments were conducted to demonstrate the effectiveness of the vision-guided docking system of the AUV.  相似文献   

卫星遥感监测城市扩展与环境变化的研究   总被引：2，自引：0，他引：2  

戴昌达  唐伶俐  陈刚  王杰生  杨幼昶 《遥感学报》1995,(1)

本文阐述应用北京地区自１９８４年至１９９２年４景秋季的ＴＭ图像，通过高精度几何配准，辐射水准归一化，热图像条纹噪声消除，各种干扰因素的识别．压抑、剔除，目标信息的增强、提取，以及背景影像的生成等图像应用处理，直接获得试区８年间城镇建设用地、绿地、水体，城市热岛等环境要素变化动态，快速制出客观反映城市扩展变化的系列图件。  相似文献   

机载短波红外分光谱扫描数据进行油气藏勘查的模式识别研究     

李加洪  朱振海 《遥感学报》1995,(3)

本文通过图像辐射恢复处理消除了大范围航空短波红外分光谱扫描图像的辐射畸变。以土壤吸附烃的光谱特性为依据，通过对训练区图像的因子分析，在主因子空间上，确定出土壤吸附烃异常的特征方向。通过确定方向因子分析的处理，实现了大范围的油气异常信息的识别、提取与分类。  相似文献