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《电子与信息学报》2006,(12)
论文一种基于钟摆模型的舰船目标成像方法...........................................................雷杰,邢孟道,保铮(1)一种用各向异性扩散方程抑制SAR相干斑噪声的方法...............................................黄倩,张冰尘,王岩飞(7)基于自适应加权方法的复值SAR图像的频域压缩改进算法.................................................孙明,李春升(12)星载极化SAR原始数据模拟研究.......................................................................岳海霞,杨汝良(16)采用Lanczos算法快速估计噪声子空间......… 相似文献
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基于DCT的SAR原始数据压缩算法分析 总被引:1,自引:0,他引:1
根据合成孔径雷达(SAR)原始数据经离散余弦变换(DCT)后的系数特性,分析了在DCT域按各子带能量分布作变比特块自适应量化的算法--DCT域块自适应量化(DCT-BAQ),并将该方法与时域BAQ算法作了比较.结合一组实测SAR原始数据,用两种算法分别进行了压缩和解压缩,并计算了数据域及图像域信噪比,给出了两种压缩算法所成的图像.实验证明,在相同的比特率下,DCT-BAQ算法的数据域和图像域信噪比均比时域BAQ算法高.数据域信噪比增加1.38~1.94 dB,图像域信噪比增加1.56~1.91 dB.加之DCT变换是实数运算、有快速算法,所以将它用于SAR原始数据压缩有一定的优越性. 相似文献
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由于合成孔径雷达(SAR)原始数据的相关性很低,直接压缩原始数据是比较困难的。该文提出一种新算法,先对SAR原始数据作距离聚焦处理,使其在方位向具有较强的相关性,再沿方位向作矢量线性预测,并对预测残差序列作分块自适应量化。结合一组实测SAR原始数据,用3种算法分别进行了压缩和解压缩,并计算了数据域及图像域信噪比,给出了3种压缩算法所成的图像。实验表明,在相同比特率条件下,该文算法得到的数据域信噪比和图像域信噪比均比BAQ算法高。该文算法的计算量远小于有关文献给出的距离聚焦后的压缩方法。 相似文献
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基于二维查找表结构的SAR原始数据自适应频域压缩算法 总被引:1,自引:1,他引:1
该文针对实际SAR多普勒中心偏移及多普勒谱分裂问题,提出基于一维查找表的自适应多普勒非均匀压缩比分配方法,该方法结合一维量化编码查找表构成二维查找表结构的SAR原始数据自适应频域压缩算法。该文推导了SAR距离向回波频谱解析式,给出距离向非均匀压缩比分配通用方案。实际数据处理结果表明,该方法比传统频域类压缩算法具有更好的信噪比及鲁棒性。理论分析结果表明,其运算量提高很小,易于工程实现。 相似文献
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基于DCT的分块自适应量化算法及其用于SAR原始数据压缩 总被引:1,自引:0,他引:1
该文提出了一种基于离散余弦变换(DCT)和分块自适应量化相结合的SAR原始数据压缩算法。利用SAR原始数据满足局部平稳高斯随机过程的特点,通过将DCT系数进行重排,并对重排后的系数矩阵进行有效的量化比特分配和分块自适应量化,从而大幅度提高了量化增益。通过对真实SAR原始数据的压缩实验结果表明:该文算法与BAQ算法相比,以相对较低的运算复杂度增加,使图像域的压缩性能指标有了明显提高。 相似文献
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星载SAR原始数据BAQ压缩算法性能评估 总被引:1,自引:1,他引:1
对星载合成孔径雷达(SAR)原始数据压缩算法的压缩性能评估是全面了解算法性能、合理选择算法方案的有效手段。该文模拟了以真实SAR图像为背景,引入点目标阵列的SAR回波数据;定义了综合评估指标;对分块自适应量化(BAQ)算法进行了不同分块方案、不同压缩比下的压缩实验;得到了一系列评估指标的计算结果。研究结果表明:BAQ算法对图像域的空间分辨率没有影响;不会引起图像的几何失真;对辐射分辨率影响很小;压缩引起的图像主瓣峰值失真不能够用统一的因子校正。同时该综合评价指标也可以推广到其他压缩算法评估中。 相似文献
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A comparison of several algorithms for SAR raw data compression 总被引:16,自引:0,他引:16
Benz U. Strodl K. Moreira A. 《Geoscience and Remote Sensing, IEEE Transactions on》1995,33(5):1266-1276
Proposes new algorithms for synthetic aperture radar (SAR) raw data compression and compares the resulting image quality with the quality achieved by commonly used methods. The compression is carried out in time and frequency domain, with statistic, crisp, and fuzzy methods. The algorithms in the time domain lead to high resolution and a good signal-to-noise ratio, but they do not optimize the performance of the compression according to the frequency envelope of the signal power in both range and azimuth directions. The hardware requirements for the compression methods in the frequency domain are significant, but a higher performance is obtained. Even with a data rate of 3 bits/sample, a satisfactory phase accuracy is achieved which is an essential parameter for polarimetric and interferometric applications. Preliminary analysis concerning the suitability of the proposed algorithms for different SAR applications shows that the compression ratio should be adaptively selected according to the specific application 相似文献
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网格编码矢量量化在SAR原始数据压缩中的应用 总被引:1,自引:0,他引:1
本文提出了一种结合传统的块自适应量化与网格编码矢量量化对SAR原始数据进行压缩的方法。首先对SAR原始数据实施块自适应量化以减小数据的动态范围,然后对块自适应量化后的数据进行网格编码矢量量化。该方法在考虑了SAR原始数据特性的基础上较好地利用了矢量的空间相关性和信号的时间相关性,进一步提高了量化增益。仿真结果表明,该方法在SAR原始数据的压缩中取得了很好的效果。 相似文献
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Compression of complex-valued SAR images 总被引:7,自引:0,他引:7
Synthetic aperture radars (SAR) are coherent imaging systems that produce complex-valued images of the ground. Because modern systems can generate large amounts of data, there is substantial interest in applying image compression techniques to these products. We examine the properties of complex-valued SAR images relevant to the task of data compression. We advocate the use of transform-based compression methods but employ radically different quantization strategies than those commonly used for incoherent optical images. The theory, methodology, and examples are presented. 相似文献
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基于2D实值离散Gabor变换的SAR原始数据压缩 总被引:1,自引:1,他引:1
该文采用时频分析的方法,结合合成孔径雷达(SAR)原始数据的线性调频特性,提出了一种基于2D实值离散Gabor变换的SAR原始数据压缩方法。该方法对I,Q两路原始数据进行分块,先对每一块进行二维实值离散Gabor变换(2D-RDGT),在时频平面内对各频率平面根据方差进行比特分配,然后采用BAQ量化各频率平面。用同一块数据进行压缩解压缩成像实验并与已有的方法进行比较,实验结果表明该文提出的方法在数据域和图像域的性能都优于已有的方法。 相似文献
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Doppler centroid frequency is an essential parameter in the imaging processing of the Scanning mode Synthetic Aperture Radar (ScanSAR). Inaccurate Doppler centroid frequency will result in ghost images in imaging result. In this letter, the principle and algorithms of Doppler centroid frequency estimation are introduced. Then the echo data of ScanSAR system is analyzed. Based on the algorithms of energy balancing and correlation Doppler estimator in the estimation of Doppler centroid frequency in strip mode SAR, an improved method for Doppler centroid frequency estimation in ScanSAR is proposed. The method has improved the accuracy of Doppler centroid frequency estimation in ScanSAR by zero padding between burst data. Finally, the proposed method is validated with the processing of ENVironment SATellite Advanced Synthetic Aperture Radar (ENVISAT ASAR) wide swath raw data. 相似文献
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Feature-enhanced synthetic aperture radar image formation based onnonquadratic regularization 总被引:5,自引:0,他引:5
We develop a method for the formation of spotlight-mode synthetic aperture radar (SAR) images with enhanced features. The approach is based on a regularized reconstruction of the scattering field which combines a tomographic model of the SAR observation process with prior information regarding the nature of the features of interest. Compared to conventional SAR techniques, the method we propose produces images with increased resolution, reduced sidelobes, reduced speckle and easier-to-segment regions. Our technique effectively deals with the complex-valued, random-phase nature of the underlying SAR reflectivities. An efficient and robust numerical solution is achieved through extensions of half-quadratic regularization methods to the complex-valued SAR problem. We demonstrate the performance of the method on synthetic and real SAR scenes. 相似文献