共查询到20条相似文献，搜索用时 140 毫秒
1.
H. Aghababaee J. Amini Y. C. Tzeng J. T. Sri Sumantyo 《Journal of the Indian Society of Remote Sensing》2013,41(4):739-747
The paper presents an effective way of detecting the changes of multi-temporal synthetic aperture radar (SAR) images. An accurate unsupervised change detection method that combines the intensity information and the fractal dimension of SAR images is proposed based on the fractal genetic model (FGM). The model computes firstly the local fractal dimension of the SAR images to obtain the fractal image and next a new proposed measure (D) is calculated from the normalized ratio of SAR images and the normalized difference of fractal images. Finally, the change map is derived by minimizing a cost function using a genetic algorithm (GA) on the derived image from the measure. Experimental results of detecting changes from SAR images acquired by ASAR on board ENVISAT and ALOS-PALSAR reveal that the proposed method is an effective and efficient tool for change detection from SAR images. 相似文献
2.
针对SAR与光学图像的融合问题,提出一种基于SAR图像中纹理特征的Contourlet变换融合方法。利用灰度共生矩阵法提取SAR图像的纹理特征,分析各个纹理特征间的相关性,得到重要纹理特征图。用HSV变换提取光学图像的强度分量。将重要纹理特征和强度分量利用改进的Contourlet多尺度变换融合,得到新的强度分量。通过HSV逆变换得到SAR与光学的融合图像。利用Landsat8和Cosmo-SkyMed图像进行融合实验,并与小波、HSV、Brovey、Contourlet变换融合方法对比分析,实验表明该方法能够较好的保持光学图像的光谱特征和SAR图像的纹理、强散射特征,增加图像细节信息,提高图像可解译性。 相似文献
3.
JIANG Liming LIAO Mingsheng ZHANG Lu LIN Hui 《地球空间信息科学学报》2007,10(2):111-116
An unsupervised change-detection method that considers the spatial contextual information in a log-ratio difference image generated from multitemporal SAR images is proposed. A Markov random filed (MRF) model is particularly employed to exploit statistical spatial correlation of intensity levels among neighboring pixels. Under the assumption of the independency of pixels and mixed Gaussian distribution in the log-ratio difference image, a stochastic and iterative EM-MPM change-detection algorithm based on an MRF model is developed. The EM-MPM algorithm is based on a maximiser of posterior marginals (MPM) algorithm for image segmentation and an expectation-maximum (EM) algorithm for parameter estimation in a completely automatic way. The experiment results obtained on multitemporal ERS-2 SAR images show the effectiveness of the proposed method. 相似文献
4.
An unsupervised change-detection method that considers the spatial contextual information in a log-ratio difference image generated from multitemporal SAR images is proposed. A Markov random filed (MRF) model is particularly employed to exploit statistical spatial correlation of intensity levels among neighboring pixels. Under the assumption of the independency of pixels and mixed Gaussian distribution in the log-ratio difference image, a stochastic and iterative EM-MPM change-detection algorithm based on an MRF model is developed. The EM-MPM algorithm is based on a maximiser of posterior marginals (MPM) algorithm for image segmentation and an expectation-maximum (EM) algorithm for parameter estimation in a completely automatic way. The experiment results obtained on multitemporal ERS-2 SAR images show the effectiveness of the proposed method. 相似文献
5.
Interference suppression in synthesized SAR images 总被引：4，自引：0，他引：4
6.
Using SAR Images to Detect Ships From Sea Clutter 总被引：4，自引：0，他引：4
Mingsheng Liao Changcheng Wang Yong Wang Liming Jiang 《Geoscience and Remote Sensing Letters, IEEE》2008,5(2):194-198
An innovative constant false alarm rate (CFAR) algorithm was studied for ship detection using synthetic aperture radar (SAR) images of the sea. Two advances were achieved. An alpha-stable distribution rather than a traditional Weibull or -distribution was used to model the distribution of sea clutter. The distribution of sea clutter in a SAR image was typically heterogeneous, caused mainly by variable wind and current conditions. Image segmentation was carried out to improve the homogeneity of the distribution in each subimage or region. In comparison with ship detection using the CFAR algorithms based on the Weibull or K -distribution, our algorithm detected the most number of ships with the smallest number of false alarms. 相似文献
7.
Topographic corrections of synthetic aperture radar (SAR) images over hilly regions are vital for retrieval of correct backscatter values associated with natural targets. The coarse resolution external digital elevation models (DEM) available for topographic corrections of high resolution SAR images often result into degradation of spatial resolution or improper estimation of backscatter values in SAR images. Also, many a times the external DEMs do not spatially co-register well with the SAR data. The present study showcases the methodology and results of topographic correction of ALOS-PALSAR image using high resolution DEM generated from the same data. High resolution DEMs of Jaipur region, India were generated using multiple pair SAR images acquired from ALOS-PALSAR using interferometric (InSAR) techniques. The DEMs were validated using differential global positioning system measured elevation values as ground control points and were compared with photogrammetric DEM (advanced spaceborne thermal emission and reflection radiometer – ASTER) and SRTM (Shuttle Radar Topography Mission) DEM. It was observed that ALOS-PALSAR images with optimum baseline parameters produced high resolution DEM with better height accuracy. Finally, the validated DEM was used for topographic correction of ALOS-PALSAR images of the same region and were found to produce better result as compared with ASTER and SRTM-DEM. 相似文献
8.
Abstract Artificial neural networks (ANN) have recently been popularly used in image classification. Input features to most ANNs are extracted based on a one class per pixel basis. This requires a large number of training samples and thus a slow training rate. In this paper, we describe the use of a windowing technique to extract textural features such as average intensity, second moment of intensity histogram and fractal surface dimension from an image. This method of image characterization reduces the number of training samples efficiently, yet retains a reasonable overall classification accuracy. The ANN is trained based on the back‐error propagation algorithm. The method is applied for landuse classification of Synthetic Aperture Radar (SAR) images. An example is given for a site in Kedah State, Malaysia. The SAR images (HH,HV,VV) were taken by the Canadian Centre for Remote Sensing (CCRS) CV‐580 airborne C‐band SAR system in November 1993 during their GlobeSAR mission in Malaysia. These multi‐polarization SAR images are co‐registered with a Landsat Thematic Mapper (TM) channel 5 image from same area. An overall classification accuracy of about 86.95% is achieved using windowing technique, as compared to 68.22% based on one class per pixel approach. This shows that through fractal and textural information, the windowing technique when applied in an ANN classifier has a great potential in remote sensing applications. 相似文献
9.
SAR图像可以看作是真实反映地物后向散射特性的无噪图像与相干斑噪声的乘积,通过贝叶斯估计从图像观测值估计出图像真值即可去除相干斑.而贝叶斯去斑的关键在于建立能与SAR图像特性相匹配的先验信息模型.用MembraneMRF模型对先验信息建模,克服了以往所用GMRF模型对参数估计十分敏感的问题,并通过对该模型邻域结构的自适应调整来分类处理处于匀质区域和含结构特征区域的像元,在有效抑制相干斑的同时较好地保持图像的结构特征.仿真和实际SAR图像数据的实验结果,验证了所提方法的有效性. 相似文献
10.
SAR影像中海洋浮油膜特征分割的Level Set方法 总被引：1，自引：0，他引：1
介绍了一种全新的区域影像分割技术--基于迎风格式偏微分方程（PDE）的Level Set方法进行海洋浮油膜特征提取.在该方法中,海洋浮油膜特征表示为扩散界面,影像灰度的梯度决定了界面扩散的方向和强度.界面边缘在影像灰度差异动力和曲率流的共同作用下不断向外扩散,能够有效地克服尖锐突起和裂缝等,在特征边缘趋于稳定和光滑.同时,该方法对高噪声具有一定抑制作用,适用于低对比度高噪声图像,特别是SAR图象中特征提取.以不同地区ERS-2 SAR图像中海洋浮油膜提取为例,进行方法验证,同时对传统的影像分割技术进行对比. 相似文献
11.
Sahel Mahdavi Bahram Salehi Cecilia Moloney Weimin Huang Brian Brisco 《International Journal of Digital Earth》2018,11(7):703-729
Speckle degrades the radiometric quality of a Synthetic Aperture Radar (SAR) image. Previous methods for speckle reduction have used a fixed-size window for filtering the entire image. This, however, may not be effective for the entire image, as land covers of different sizes require different filtering windows. In this paper, a novel method is proposed by which each pixel in the image is filtered with a window appropriate for the size of object within it. The real in-phase and the imaginary quadrature components of the SAR images determine the best window size and the pixels in the intensity image are filtered using their own optimal windows. The proposed method is presented for both single- and multi-polarized SAR images, and the results of several common filters that were modified are presented. This approach is applied to two RADARSAT-2 images: one over San Francisco, California, USA and the other over St. John’s, Newfoundland and Labrador, Canada, producing results that were similar to, or outperformed, comparable filters while retaining details and suppressing speckle effectively. While the method was successful for single-look intensity data, it offers great potential for multi-look and amplitude data as well. 相似文献
12.
为提高SAR影像岸线自动分割的精度和效率,针对传统二进制(影像序列生成的金字塔步长底数为a=2)多尺度C-V模型对初始条件敏感、收敛速度低的问题,提出指数型(影像序列生成的底数为a≥1)多尺度影像序列生成方法,本方法将传统多尺度影像序列的生成方式的底数2量化为a≥1的任意数,并应用筛选因素进行自动地快速识别海岸线。从海岸线分割结果和所需时间方面与已有传统二进制C-V模型算法进行对比,实验表明本文算法在保证精度的条件下单次迭代逼近海岸线的计算量上小于传统即二进制多尺度C-V模型的单次迭代计算量,总迭代次数有所减少,时间效率有所提高,提高了岸线自动分割的精度和效率。 相似文献
13.
14.
Tello M. Lopez-Martinez C. Mallorqui J.J. 《Geoscience and Remote Sensing Letters, IEEE》2005,2(2):201-205
Carrying out an effective control of fishing activities is essential to guarantee a sustainable exploitation of sea resources. Nevertheless, as the regulated areas are extended, they are difficult and time consuming to monitor by means of traditional reconnaissance methods such as planes and patrol vessels. On the contrary, satellite-based synthetic aperture radar (SAR) provides a powerful surveillance capability allowing the observation of broad expanses, independently from weather effects and from the day and night cycle. Unfortunately, the automatic interpretation of SAR images is often complicated, even though undetected targets are sometimes visible by eye. Attending to these particular circumstances, a novel approach for ship detection is proposed based on the analysis of SAR images by means of the discrete wavelet transform. The exposed method takes advantage of the difference of statistical behavior among the ships and the surrounding sea, interpreting the information through the wavelet coefficients in order to provide a more reliable detection. The analysis of the detection performance over both simulated and real images confirms the robustness of the proposed algorithm. 相似文献
15.
提出并实现了一种基于加权最小二乘的低相干SAR像对精配准新方法。该方法借助一幅与主、辅影像相干性都较高的第三幅影像来完成低相干SAR影像对的初步配准,利用加权最小二乘法求出二者间的坐标映射函数,从而快速高效地实现低相干SAR影像对的高精度亚像元级配准。采用ERS-1/2实际数据的配准实验,验证了该方法可以提高低相干SAR像对的干涉图质量,提高二者之间的相干性和控制点的配准精度,改善低相干SAR影像对的配准效果,在一定程度上解决了PS InSAR技术中低相干SAR影像对的配准问题。 相似文献
16.
Fusun Balik Sanli Saygin Abdikan Mustafa Tolga Esetlili Filiz Sunar 《Journal of the Indian Society of Remote Sensing》2017,45(4):591-601
This research aimed to explore the fusion of multispectral optical SPOT data with microwave L-band ALOS PALSAR and C-band RADARSAT-1 data for a detailed land use/cover mapping to find out the individual contributions of different wavelengths. Many fusion approaches have been implemented and analyzed for various applications using different remote sensing images. However, the fusion methods have conflict in the context of land use/cover (LULC) mapping using optical and synthetic aperture radar (SAR) images together. In this research two SAR images ALOS PALSAR and RADARSAT-1 were fused with SPOT data. Although, both SAR data were gathered in same polarization, and had same ground resolution, they differ in wavelengths. As different data fusion methods, intensity hue saturation (IHS), principal component analysis, discrete wavelet transformation, high pass frequency (HPF), and Ehlers, were performed and compared. For the quality analyses, visual interpretation was applied as a qualitative analysis, and spectral quality metrics of the fused images, such as correlation coefficient (CC) and universal image quality index (UIQI) were applied as a quantitative analysis. Furthermore, multispectral SPOT image and SAR fused images were classified with Maximum Likelihood Classification (MLC) method for the evaluation of their efficiencies. Ehlers gave the best score in the quality analysis and for the accuracy of LULC on LULC mapping of PALSAR and RADARSAT images. The results showed that the HPF method is in the second place with an increased thematic mapping accuracy. IHS had the worse results in all analyses. Overall, it is indicated that Ehlers method is a powerful technique to improve the LULC classification. 相似文献
17.
提出了一种探测多通道SAR影像中道路的新方案。首先阐述了从边缘探测器中建构线状探测器。然后,介绍了应用到SAR影像中的多参数统计假设检验方法。利用传统的亮线提取过程对初期结果进行了矢量化。实验表明:该方法应用到全极化SAR影像中的道路的提取中效果较好。 相似文献
18.
一种多孔径SAR图像目标检测方法 总被引：2，自引：0，他引：2
提出了一种多孔径SAR图像目标检测方法,充分利用SAR图像幅度和相位信息来区分人造目标和杂波。由于人造目标的回波能量往往集中在部分方位角范围内,当该部分方位角范围所对应的多个子孔径图像中存在目标时,其局部相关性较强,因此,该方法利用多个子孔径图像之间的相干系数检测目标。实验结果表明,该方法有效地提高了目标检测概率,同时降低了虚警概率。 相似文献
19.
Provides a first assessment of a coregistration technique suitable for multiangle fine spatial resolution synthetic aperture radar (SAR) images. The technique is based on crossroad and road junction extraction and matching and exploits recently introduced road extraction routines for SAR data. These features are matched using relational and geometrical analysis. Results are encouraging and show the possibility to exploit multiangle SAR available from future airborne and satellite missions. 相似文献
20.
根据高分辨率SAR图像上建筑区的影像特征, 提出了基于灰度共生矩阵(gray-level cooccurrence Matrix, GLCM)纹理分析的建筑区提取方法, 该方法由初步定位和边界调整2个步骤组成, 均遵循特征计算、基于Bhattacharyya距离的特征选择和KNN分类流程, 所不同的是2个步骤中分别采用了逐块和逐点计算纹理特征的方式以兼顾纹理分析的效率和准确性。文中对不同SAR传感器获取的图像进行了实验。实验结果表明, 选用具有最大Bhattacharyya距离值的3或4个特征可以获得较好的初步定位结果, 建筑区的检测率超过80%, 虚警率低于10%；随着边界调整的进行, 检测到的建筑区边界逐渐接近于真实边界。实验结果验证了该算法的有效性。 相似文献