基于协克立金方法的遥感图像融合     

刘立  李培军  马德锋 《国土资源遥感》2007,18(3):8-12

 协克立金方法是一种多元最优无偏的线性估值方法，已被广泛应用于许多领域。本文将协克立金方法应用于遥感图像的融合中，并与经典的基于主成分分析方法的融合结果进行定性和定量比较和分析。首先，通过计算实验变异函数，进行变异函数理论模型拟合； 然后，运用3种不同协克立金方法对较低分辨率的多光谱图像和较高分辨率的全色图像进行融合。实验结果表明： 基于简单协克立金方法融合的图像空间分辨率最好； 普通协克立金方法融合的图像光谱保真性最好； 标准化的协克立金方法融合的效果介于两者之间。  相似文献   

Image-based correlation of Laser Scanning point cloud time series for landslide monitoring     

《International Journal of Applied Earth Observation and Geoinformation》2014

Very high resolution monitoring of landslide kinematics is an important aspect for a physical understanding of the failure mechanisms and for quantifying the associated hazard. In the last decade, the potential of Terrestrial Laser Scanning (TLS) to monitor slow-moving landslides has been largely demonstrated but accurate processing methods are still needed to extract useful information available in point cloud time series. This work presents an approach to measure the 3D deformation and displacement patterns from repeated TLS surveys. The method is based on the simplification of a 3D matching problem in a 2D matching problem by using a 2D statistical normalized cross-correlation function. The computed displacement amplitudes are compared to displacements (1) calculated with the classical approach of Iterative Closest Point and (2) measured from repeated dGPS observations. The performance of the method is tested on a 3 years dataset acquired at the Super-Sauze landslide (South French Alps). The observed landslide displacements are heterogeneous in time and space. Within the landslide, sub-areas presenting different deformation patterns (extension, compression) are detected by a strain analysis. It is demonstrated that pore water pressure changes within the landslide is the main controlling factor of the kinematics.  相似文献   

Hybrid region merging method for segmentation of high-resolution remote sensing images     

《ISPRS Journal of Photogrammetry and Remote Sensing》2014

Image segmentation remains a challenging problem for object-based image analysis. In this paper, a hybrid region merging (HRM) method is proposed to segment high-resolution remote sensing images. HRM integrates the advantages of global-oriented and local-oriented region merging strategies into a unified framework. The globally most-similar pair of regions is used to determine the starting point of a growing region, which provides an elegant way to avoid the problem of starting point assignment and to enhance the optimization ability for local-oriented region merging. During the region growing procedure, the merging iterations are constrained within the local vicinity, so that the segmentation is accelerated and can reflect the local context, as compared with the global-oriented method. A set of high-resolution remote sensing images is used to test the effectiveness of the HRM method, and three region-based remote sensing image segmentation methods are adopted for comparison, including the hierarchical stepwise optimization (HSWO) method, the local-mutual best region merging (LMM) method, and the multiresolution segmentation (MRS) method embedded in eCognition Developer software. Both the supervised evaluation and visual assessment show that HRM performs better than HSWO and LMM by combining both their advantages. The segmentation results of HRM and MRS are visually comparable, but HRM can describe objects as single regions better than MRS, and the supervised and unsupervised evaluation results further prove the superiority of HRM.  相似文献   

Quantitative evaluation of variations in rule-based classifications of land cover in urban neighbourhoods using WorldView-2 imagery     

《ISPRS Journal of Photogrammetry and Remote Sensing》2014

The increasing availability of high resolution imagery has triggered the need for automated image analysis techniques, with reduced human intervention and reproducible analysis procedures. The knowledge gained in the past might be of use to achieving this goal, if systematically organized into libraries which would guide the image analysis procedure. In this study we aimed at evaluating the variability of digital classifications carried out by three experts who were all assigned the same interpretation task. Besides the three classifications performed by independent operators, we developed an additional rule-based classification that relied on the image classifications best practices found in the literature, and used it as a surrogate for libraries of object characteristics. The results showed statistically significant differences among all operators who classified the same reference imagery. The classifications carried out by the experts achieved satisfactory results when transferred to another area for extracting the same classes of interest, without modification of the developed rules.  相似文献   

Multi-scale pore structure of COx claystone: Towards the prediction of fluid transport     

《Marine and Petroleum Geology》2015

We aim to relate the morphology of the pore network of finely porous claystones to their fluid transport properties. By using Focused Ion Beam in combination with Scanning Electron Microscopy (FIB/SEM), we image the pore network of COx claystone from 2D image stacks and as 3D reconstructed volumes. Our FIB/SEM samples are representative of the mesoscopic matrix clay. Porosity resolvable by this technique is in the range 1.7–5.9% with peak pore sizes of 50–90 nm. 3D pore network skeletonization provides connected pore volumes between end surfaces, tortuosity, density, and shortest pore paths with their pore size distribution. At higher resolution, 2D transmission electron microscopy (TEM) reveals large amounts of smaller pores (2–20 nm) between clay aggregates, associated to a local porosity of 14–25%, and peak sizes of 4–6 nm. Liquid permeability predictions with Katz–Thompson model, at the FIB/SEM volume scale and at the TEM surface scale, are in good agreement with macroscopic measurements (on the order of 10⁻²⁰ m²), showing that both mesopore sizes (peaks at 50–90 nm and 4–6 nm), located within the clay matrix, contribute to liquid transport.  相似文献   

A combined spectrophotometric and morphometric study of the lunar mare dome fields near Cauchy, Arago, Hortensius, and Milichius     

Christian Wöhler  Raffaello Lena  Jim Phillips  Zac Pujic  Geologic Lunar Research Group 《Icarus》2006,183(2):237-264

In this study we examine the spectral and morphometric properties of the four important lunar mare dome fields near Cauchy, Arago, Hortensius, and Milichius. We utilize Clementine UV-vis multispectral data to examine the soil composition of the mare domes while employing telescopic CCD imagery to compute digital elevation maps in order to determine their morphometric properties, especially flank slope, height, and edifice volume. After reviewing previous attempts to determine topographic data for lunar domes, we propose an image-based 3D reconstruction approach which is based on a combination of photoclinometry and shape from shading. Accordingly, we devise a classification scheme for lunar mare domes which is based on a principal component analysis of the determined spectral and morphometric features. For the effusive mare domes of the examined fields we establish four classes, two of which are further divided into two subclasses, respectively, where each class represents distinct combinations of spectral and morphometric dome properties. As a general trend, shallow and steep domes formed out of low-TiO₂ basalts are observed in the Hortensius and Milichius dome fields, while the domes near Cauchy and Arago that consist of high-TiO₂ basalts are all very shallow. The intrusive domes of our data set cover a wide continuous range of spectral and morphometric quantities, generally characterized by larger diameters and shallower flank slopes than effusive domes. A comparison to effusive and intrusive mare domes in other lunar regions, highland domes, and lunar cones has shown that the examined four mare dome fields display such a richness in spectral properties and 3D dome shape that the established representation remains valid in a more global context. Furthermore, we estimate the physical parameters of dome formation for the examined domes based on a rheologic model. Each class of effusive domes defined in terms of spectral and morphometric properties is characterized by its specific range of values for lava viscosity, effusion rate, and duration of the effusion process. For our data set we report lava viscosities between about 10² and , effusion rates between 25 and , and durations of the effusion process between three weeks and 18 years. Lava viscosity decreases with increasing R₄₁₅/R₇₅₀ spectral ratio and thus TiO₂ content; however, the correlation is not strong, implying an important influence of further parameters like effusion temperature on lava viscosity.  相似文献   

基于全景真三维技术的新型智慧城市时空信息基础设施探索     

任超  霍文虎  张茜  张旻 《地理信息世界》2017,24(4)

我国新型智慧城市的建设对城市时空信息基础设施提出了更高的要求,迫切需要加强包括大数据、云计算等新技术的深入应用。本文重点探讨基于多传感器技术(包括机载激光扫描技术、多角度倾斜摄影技术在内的航空摄影)和高度自动化后处理新技术的全景真三维技术特点及优势,并以北京城市副中心为例,探索基于全景真三维技术的智慧城市时空信息基础设施建设及其应用。实践表明,全景真三维技术能够快速提供真实统一、高精度、多层次的城市模型数据,为城市规划、建设、治理和运营提供了事半功倍的信息化手段,是一种构建新型智慧城市时空信息基础设施的新思路。  相似文献   

扫描线并行跟踪算法     

王季青  钱曾波 《测绘学院学报》1999,(2)

在等值线图像的跟踪过程中, 常常由于原始图纸的质量较低或扫描仪的原因, 会出现细化错误和跟踪不完全, 从而导致理解困难和识别错误。作者提出的并行跟踪算法省去了细化过程, 以扫描线方式并行地检出图像信息, 并将输入序列描述为正规表达式的正规集, 构造一个确定有限自动机（ ＤＦＡ） , 对正规集进行识别, 从而达到对相关图像信息的整体提取。  相似文献   

基于RS和GIS的大面积区域路网现状信息调查研究     

白宝玉  冯晓 《四川测绘》2010,33(3):113-115

提出了一种有效的道路现状普查模式,利用数学形态学和矢量化相结合的方法,根据最新遥感影像对大面积区域路网进行适时提取。能够在较短的时间内将大面积区域的现状路网数据入库并制作专题路网现状地图,通过实际应用,证明方法可靠,可推广利用。  相似文献   

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