共查询到20条相似文献，搜索用时 31 毫秒
1.
Image fusion techniques integrate complimentary information from multiple image sensor data such that the new images are more
suitable for the purpose of human visual perception and computer based processing tasks for extraction of detail information.
As an important part of image fusion algorithms, pixel-level image fusion can combine spectral information of coarse resolution
imagery with finer spatial resolution imagery. Ideally, the method used to merge data sets with high-spatial and highspectral
resolution should not distort the spectral characteristics of the high-spectral resolution data. This paper describes the
Discrete Wavelet Transform (DWT) algorithm for the fusion of two images using different spectral transform methods and nearest
neighbor resampling techniques. This research paper investigates the performance of fused image with high spatial resolution
Cartosat-1(PAN) with LISS IV and Cartosat-1(PAN) sensor images with the LISS III sensor image of Indian Remote Sensing satellites.
The visual and statistical analysis of fused images has shown that the DWT method outperforms in terms of Geometric, Radiometric,
and Spectral fidelity. 相似文献
2.
《International Journal of Digital Earth》2013,6(3):235-257
The accuracy of topographic correction of Landsat data based on a Digital Surface Model (DSM) depends on the quality, scale and spatial resolution of the DSM data used and the co-registration between the DSM and the satellite image. A physics-based bidirectional reflectance distribution function (BRDF) and atmospheric correction model in conjunction with a 1-second DSM was used to conduct the analysis in this paper. The results show that for the examples used from Australia, the 1-second DSM, can provide an effective product for this task. However, it was found that some remaining artefacts in the DSM data, originally due to radar shadow, can still cause significant local errors in the correction. Where they occur, false shadows and over-corrected surface reflectance factors can be observed. More generally, accurate co-registration between satellite images and DSM data was found to be critical for effective correction. Mis-registration by one or two pixels could lead to large errors of retrieved surface reflectance factors in gully and ridge areas. Using low-resolution DSM data in conjunction with high-resolution satellite images will also fail to correct significant terrain components where they occur at the finer scales of the satellite images. DSM resolution appropriate to the resolution of satellite image and the roughness of the terrain is needed for effective results, and the rougher the terrain, the more critical will be the accurate registration. 相似文献
3.
为满足在坡度陡、高差大的复杂地形地区高精度DEM制图的需要,在传统的雷达干涉测量技术的基础上,通过引入外部DEM,建立外部DEM模拟相位和干涉解缠相位的对应关系,构建多维线性模型,进行线性回归分析,去除误差相位趋势;同时根据引入的外部DEM估计高程的误差范围,进行高程点的滤波,达到精化DEM的目的,形成最终的DEM产品。该方法已经应用于高分辨雷达影像（COSMO数据）在云南德钦地区DEM地形图的制作,通过GPS数据的验证,其精度达到了国家1∶50 000 DEM制图要求。 相似文献
4.
净初级生产力遥感估算模型空间尺度转换 总被引：2，自引：1，他引：2
采用基于混合像元的结构分析方法和支持向量机(SVM)算法,建立了高分辨率遥感数据(TM)向低分辨率遥感数据(MODIS)的尺度转换模型,实现了由高分辨率遥感数据获得的NPP向低分辨率遥感数据获得的NPP的空间尺度转换。对低分辨率遥感数据(MODIS)估算的NPP结果进行了尺度效应校正。结果表明:SVM回归模型模拟出的尺度效应校正因子Rj_corrected与1-F中覆盖度草地之间的相关性较高,R2达到0.81。尺度效应校正前的NPPMODIS与NPPTM的相关性较低,R2仅为0.69,RMSE为3.47;尺度效应校正后的NPPMODIS_corrected与NPPTM的相关性较高,R2达到0.84,RMSE为1.87。因此,经过尺度效应校正后的NPP无论是在相关性还是在误差方面有了很大程度的提高。 相似文献
5.
Kátia Kellem da Rosa Cláudio Wilson Mendes Jr. Jorge Arigony-Neto Jefferson Cardia Simões 《国际地球制图》2016,31(9):1032-1043
This work analysed the spatio-temporal variation of snow cover on the Kraków Ice Field, located in the King George Island, Antarctica. High spatial resolution images of COSMO-SkyMed were used in this study. These X-band images are vertically and horizontally co-polarized and their intensity data were converted to amplitude (dB). The COSMO-SkyMed images were classified by a minimum distance algorithm and post-classified based on knowledge of adjacency relationships of snow zones. Hypsometric, slope, aspect and solar radiation maps to support the interpretation of backscatter patterns in the COSMO-SkyMed images. Three radar zones were classified in these images: percolation, slush and wet snow radar zone. Positive surface air temperatures and rainfall events, registered from a meteorological station, lead to increase in wet snow and slush zones. The COSMO-SkyMed images and minimum distance algorithm were adequate to discriminate the snow cover and to assess the supraglacial melting pattern during the ablation season in the study area. 相似文献
6.
7.
Praveen K. Thakur Pradeep K. Garg Shiv P. Aggarwal Rahul D. Garg Sneh Mani 《Journal of the Indian Society of Remote Sensing》2013,41(4):933-945
The current study has used Synthetic Aperture Radar (SAR) satellite data to estimate the Snow Cover Area (SCA) in Manali watershed of Beas River in Northwest Himalayas of Himachal Pradesh, India. SAR data used in this study is of Radarsat-2 (RS2) and Environmental Satellite (ENVISAT), Advanced Synthetic Aperture Radar (ASAR). The SAR preprocessing was done with SAR image processing tools for converting raw SAR images into calibrated geo-coded backscatter images. Maps for forest, built area, layover and shadow were created and used for masking snow cover in these areas. The backscattering ratio of wet snow to reference image threshold method with value range from ?2 to ?3 db was used to estimate wet SCA for study area. In this technique, if the threshold is too high (≥-2 db) wet SCA is overestimated and if it is too low (≤-3db), this method underestimates the SCA. The wet SCA is under/over estimated (+6 % to?8 % on average) in late spring season due to the inherent terrain and SAR imaging effects of layover/foreshortening and shadow and also due to the masking of forest areas. Overall, the SCA derived from SAR data matches well when compared with total SCA derived from cloud free optical remote sensing data products, especially during wet season. 相似文献
8.
星载高分辨率光学图像与SAR图像广泛应用于城市建筑物高度提取,但光学图像存在缺少相关卫星参数的情况,而SAR图像则存在散射特征不完整以及提取效率低等缺陷。针对以上问题,本文提出一种联合高分辨率星载光学与SAR图像的城市大面积建筑物高度快速提取方法。首先,结合支持向量机(SVM)和形态学阴影指数(MSI)快速提取光学图像中的阴影并自动测量阴影长度;之后选择多个合适样本,基于模型匹配法从SAR图像中提取高度;最后将高度与阴影长度作线性回归分析,建立数学模型来提取其他建筑物的高度。该方法将不同卫星系统的数据和特征相结合,互相弥补各自缺陷,不仅提高了效率、降低了成本,同时满足精度要求。 相似文献
9.
We present a signal processing approach using discrete wavelet transform (DWT) for the generation of complex synthetic aperture radar (SAR) images at an arbitrary number of dyadic scales of resolution. The method is computationally efficient and is free from significant system-imposed limitations present in traditional subaperture-based multiresolution image formation. Problems due to aliasing associated with biorthogonal decomposition of the complex signals are addressed. The lifting scheme of DWT is adapted to handle complex signal approximations and employed to further enhance the computational efficiency. Multiresolution SAR images formed by the proposed method are presented. 相似文献
10.
采用合成孔径雷达干涉测量（interferometric synthetic aperture radar,InSAR）技术对甘肃黑方台地区潜在的黄土滑坡开展了多时相编目、长时序监测以及失稳模式识别研究。首先,采用不同空间分辨率、不同波长的历史存档合成孔径雷达（synthetic aperture radar,SAR）数据对黑方台地区2006-12至2017-11间的潜在滑坡开展了识别研究,在2006-12至2011-03和2016-01至2016-11两个时间段均识别出数10处不稳定坡体,实地调查和光学遥感影像验证了InSAR技术识别结果的可靠性与准确性。然后,对典型不稳定滑坡体采用高空间与高时间分辨率的TerraSAR-X数据开展了长时序监测,结果表明,在InSAR监测期间,累积形变最大的滑坡体在随后的时间里均发生了滑动,并成功地捕获到滑坡体形变加速的时间点。最后,利用升降轨SAR数据开展了黄土滑坡二维形变监测研究,基于滑坡的二维形变特征并结合地形图以及光学遥感影像进一步研究了滑坡的失稳模式,现场调查结果验证了所获得滑坡失稳模式的准确性。 相似文献
11.
Shiqi Huang Xinhua CaiShunxiang Chen Daizhi Liu 《International Journal of Applied Earth Observation and Geoinformation》2011
The interaction is quite complex between a ground object and an electromagnetic wave transmitted by synthetic aperture radar (SAR). In a ground resolution cell illuminated by a radar beam, there are many chaotic scatterers and the whole scattering echo has the chaotic characteristics which is usually described with the fractal theory, and the fractal dimension can be used to detect the change information for multitemporal SAR images. In order to improve the change detection effect with fractal model, this paper proposes a new multitemporal SAR image change detection algorithm based on the fractal model and wavelet transform (called FMWT algorithm). The FMWT algorithm has two advantages. One is insensitive to speckle noise; the other is that the change detection accuracy is improved, comparing with a general fractal change detection (GFCD) algorithm. Since the FMWT algorithm adopts the two-dimensional discrete stationary wavelet transform (TDDSWT) technique, it can obtain different direction sub-images and avoid down-sampling of the discrete wavelet transform (DWT). In the paper, not only the simulative data test has been carried out, but also the real natural disaster SAR images have been checked. Experimental results verify that the FMWT algorithm is feasible for multitemporal SAR image change detection, it is not sensitive to speckle noise of SAR images, and the performance of it is better than that of the GFCD algorithm. At the same time, the size of a sliding window will bring some affection in counting fractal dimensions. 相似文献
12.
Most studies have the achieved rapid and accurate determination of soil organic carbon (SOC) using laboratory spectroscopy; however, it remains difficult to map the spatial distribution of SOC. To predict and map SOC at a regional scale, we obtained fourteen hyperspectral images from the Gaofen-5 (GF-5) satellite and decomposed and reconstructed the original reflectance (OR) and the first derivative reflectance (FDR) using discrete wavelet transform (DWT) at different scales. At these different scales, as inputs, we selected the 3 optimal bands with the highest weight coefficient using principal component analysis and chose the normalized difference index (NDI), ratio index (RI) and difference index (DI) with the strongest correlation with the SOC content using a contour map method. These inputs were then used to build regional-scale SOC prediction models using random forest (RF), support vector machine (SVM) and back-propagation neural network (BPNN) algorithms. The results indicated that: 1) at a low decomposition scale, DWT can effectively eliminate the noise in satellite hyperspectral data, and the FDR combined with DWT can improve the SOC prediction accuracy significantly; 2) the method of selecting inputs using principal component analysis and a contour map can eliminate the redundancy of hyperspectral data while retaining the physical meaning of the inputs. For the model with the highest prediction accuracy, the inputs were all derived from the wavelength range of SOC variations; 3) the differences in prediction accuracy among the different prediction models are small; and 4) the SOC prediction accuracy using hyperspectral satellite data is greatly improved compared with that of previous SOC prediction studies using multispectral satellite data. This study provides a highly robust and accurate method for predicting and mapping regional SOC contents. 相似文献
13.
为满足复杂地形景区对三维地图导览的需求,构建更为清晰的三维地图模型,提供良好的三维导览地图设计方案显得尤为重要。为了更好地与卫星影像进行贴合,DEM数据的采样密度要与卫星影像的分辨率一致。本文通过对比当下常用的四种空间插值方法的适用范围与运用特点,设置相关阈值及权重,直观比较了四种插值方法产生的插值结果,选择更适合复杂景区DEM插值的插值方法并对其进行精度提升,以此得到符合精度要求的DEM数据。最后利用相应地区的卫星影像进行地图投影及影像贴图,两种数据结合构建复杂景区的三维地图模型,给游客带来更为精确直观的定位信息和空间要素信息。 相似文献
14.
雷达后向散射模型及其在雷达图像地形影响纠正中的应用 总被引：6，自引：0，他引：6
在从雷达估测森林生物量时，经常遇到的一个问题是地形对雷达信号的影响。地形使得雷达波的入射角度改变，使每个雷达图像像元所包含的地表面积改变，由于地面的起伏，植被本身的结构也不同，纠正这种由地形而不是植被类型引起的雷达图像的变化是一个很复杂的问题，除了需要高质量的地形数据外，还必须理解植被雷达信号随地形变化的规律。提出一种可用来模拟森林及其它植被处于山坡上的雷达后向散射模型。结合DEM数据，模拟的结果可用来进行雷达图像的地形影响纠正，如果多极化或多波段图像存在，通过雷达模型可用从一种极化推导出的地形信息来纠正其它极化的图像数据。 相似文献
15.
Wetlands are the second-most valuable natural resource on Earth but have declined by approximately 70 % since 1900. Restoration and conservation efforts have succeeded in some areas through establishment of refuges where anthropogenic impacts are minimized. However, these areas are still prone to wetland damage caused by natural disasters. Severe storms such as Hurricane Irma, which made landfall as a Category 3 hurricane in southwest Florida (USA) on September 11, 2017, can cause the destruction of mangroves and other wetland habitat. Multispectral images from commercial satellites provide a means to assess the extent of the damage to different wetland habitat types with high spatial resolution (2 m pixels or finer) over large areas. Using such images presents a number of challenges, including deriving consistent and accurate classification of wetland and non-wetland vegetation. Machine learning methods have demonstrated high-accuracy mapping capabilities on small spatial scales, but require a large amount of robust training data. Meanwhile, ambitious efforts to map larger areas at finer resolutions may use hundreds of thousands of images, and therefore encounter Big-Data processing challenges. Large-scale efforts face the dilemma of adopting traditional mapping methods that may lend themselves to Big Data analytics but may result in accuracies that are inferior to new methods, or move to machine learning methods, which require robust training data. Given these considerations, we describe a version of the traditional Decision Tree (DT) approach and compare two common machine learning methods to derive land cover classes using a WorldView-2 image collected on November 12, 2018 to include one growing season after Hurricane Irma affected this area. Specifically, we compared the Support Vector Machine [SVM] and Neural Network [NN] methods, trained and validated with separate ground-truth datasets collected during a robust field campaign. Overall accuracies were only marginally different (85 % NN vs 83 % each DT and SVM), but healthy mangroves were more accurately identified with the DT (91 % vs 88 % NN and 86 % SVM), and degraded mangroves were more accurately identified with NN (62 % vs 57 % NN and 38 % DT). These results, combined with their respective training requirements, have implications for the direction with which large-scale high-resolution mapping of coastal habitats proceeds. 相似文献
16.
在西部黄土高原复杂地形地貌下构建采煤沉陷盆地和提取水平位移的难度较大,传统地表沉降监测手段只能获取线状数据,效率低,而重复轨道合成孔径雷达干涉测量技术在大梯度形变区域易出现失相干现象,难以达到矿区地表沉降监测精度要求。提出了一种基于无人机载激光雷达点云数据构建沉陷盆地和提取水平位移的方法。结合多地形因子构建深度神经网络（deep neural network,DNN）模型,提取沉陷盆地构建过程中受地形影响较小的特征稳定区,利用较优插值算法对稳定区进行拟合,得到完整沉陷盆地。为了提取采煤地表水平移动信息,将二进制形状上下文特征描述算子与多地形因子融合起来,以改进特征匹配算法。基于此设计地表水平移动提取方案,提取主断面水平移动信息,同时对水平移动提取误差与点云密度、地形因子进行定量分析。榆神矿区结果表明,利用结合地形因子的DNN模型能有效提取特征稳定区,在复杂地貌下减小了沉陷建模误差,为构建采煤沉陷盆地提供了一种新方法;利用融合地形特征的改进特征匹配算法提取的水平移动曲线符合采煤沉陷水平移动基本规律,与水平移动偏差相关性较强的地形因子可用于衡量改进特征匹配算法对水平移动提取误差的大小。 相似文献
17.
Dengsheng Lu Guiying Li Emilio Moran Mateus Batistella Corina C. Freitas 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(6):798-808
This research explored the integrated use of Landsat Thematic Mapper (TM) and radar (i.e., ALOS PALSAR L-band and RADARSAT-2 C-band) data for mapping impervious surface distribution to examine the roles of radar data with different spatial resolutions and wavelengths. The wavelet-merging technique was used to merge TM and radar data to generate a new dataset. A constrained least-squares solution was used to unmix TM multispectral data and multisensor fusion images to four fraction images (high-albedo, low-albedo, vegetation, and soil). The impervious surface image was then extracted from the high-albedo and low-albedo fraction images. QuickBird imagery was used to develop an impervious surface image for use as reference data to evaluate the results from TM and fusion images. This research indicated that increasing spatial resolution by multisensor fusion improved spatial patterns of impervious surface distribution, but cannot significantly improve the statistical area accuracy. This research also indicated that the fusion image with 10-m spatial resolution was suitable for mapping impervious surface spatial distribution, but TM multispectral image with 30 m was too coarse in a complex urban–rural landscape. On the other hand, this research showed that no significant difference in improving impervious surface mapping performance by using either PALSAR L-band or RADARSAT C-band data with the same spatial resolution when they were used for multi-sensor fusion with the wavelet-based method. 相似文献
18.
合成孔径雷达干涉测量是一种利用SAR影像复数据的相位信息提取地面三维信息的技术,它通过获取地面目标在两幅SAR影像上的相位差值来解算该点的三维坐标。有理多项式（RPC,Rational Polynomial Coefficient）模型作为一种数学意义上的几何模型,它独立于传感器和平台,简单且具有通用性,可建立地面任意坐标与影像空间的关系。本文在RPC模型用于替代星载SAR的距离多普勒模型和星载InSAR的干涉相位方程基础上,研究 RPC模型应用于星载高分辨率InSAR影像制作DEM的可行性和精度。利用兰州COSMO-SkyMed数据和资源三号三线阵数据制作的DEM为参考数据进行实验验证,RPC模型用于InSAR技术生成的DEM,中误差为7.55米。 相似文献
19.
Almeida-Filho R. Rosenqvist A. Shimabukuro Y.E. dos Santos J.R. 《Geoscience and Remote Sensing Letters, IEEE》2005,2(4):409-412
Japanese Earth Resources Satellite 1 (JERS-1) synthetic aperture radar (SAR) data were evaluated to map areas of deforestation in a Brazilian Amazo/spl circ/nia test-site. The results were compared with information derived from a Landsat TM multitemporal series. Unambiguous detection of deforested areas was observed only when the entire deforestation process (slash, burning, and terrain clearing) had already occurred. This result recommends further investigations on the effectiveness of horizontal polarization SAR data to map deforestation in a consistent basis. The cross-polarized (horizontal-vertical) channel designed to be in the ALOS/PALSAR system is expected to improve the distinction between forested and recently deforested areas. 相似文献
20.
P K Champatiray A K Roy B Prabhakaran 《Journal of the Indian Society of Remote Sensing》1995,23(2):77-86
The C-band imaging radar of ERS-1, due to its high sensitivity to terrain surface features, holds tremendous potential in topographic terrain mapping for various applications. This is being examined for geological applications, mainly structural and lithological mapping in a mineral belt of Bihar and Orissa, India. The high image contrast that facilitates structural interpretation and highlights topography on the SAR images, reflects the high sensitivity of the ERS-1-SAR to change in terrain slope in the study area. Extensive lineaments, fold structure and major lithological contacts are easily mappable from the SAR imagery. Many of the lineaments, lithological contacts and fold pattern are mapped equally from optical data (Landsat-TM and IRS-1B FCC). The close association of fold pattern and mineral deposits in the region has necessitated the study of those structures carefully from various remote sensing data products. Synergism between SAR and TM provided useful results regarding structure and lithology of the region. The advantage of SAR in highlighting topography and detecting lineaments are affected to a great extent by the speckle noise and low pixel resolution. The present study shows that future geologic interpretation demands high spatial resolution and efficient data processing technique which reduces the speckle noise more significantly. 相似文献