共查询到20条相似文献,搜索用时 46 毫秒
1.
A Generalized optimization algorithm of polarimetric contrast enhancement (GOPCE) is proposed to find optimal polarimetric states and coefficients to max-imize the received power ratio of ship to ocean clutter, which facilitates ship detection. The method is validated with a real SIR-C/X image. The results indicate that, rather than optimal polarimetric contrast enhancement, GOPCE apparently improves the contrast of ship to sea by introducing the polarimetric feature vector. 相似文献
2.
Synthetic aperture radar (SAR) imaging system is generally realized by fixed-point with the purpose of reducing system implementation scale and enhancing real-time performance. Finite word length computing error of fixed-point SAR imaging system is studied. The characteristic of computing error in SAlt imaging system is analyzed. A finite word length computing error model of SAR imaging system is built, by means of which the empirical formula of system's output noise-to-signal ratio is derived. Based on the empirical formula, SAR imaging system processing word length is presented according to different processing granularities. The validity of this proposed finite word length computing error model of SAR imaging system is verified by system level fixed-point sivaulation. 相似文献
3.
This paper extends the application of Block-matching (BM) and 3D transform-domain collabo- rative filtering (BM3D) to the noise reduction in Interfer- ometric synthetic aperture radar (InSAR) phase imagery, and proposes a denoising algorithm which can effectively remove noise and preserve fringes. Since the noise level estimated by a median estimator is not always optimal for proposed algorithm in wavelet domain, a method of calcu- lating optimal noise standard deviation is also developed. The proposed algorithm is efficient and robust. Experi- mental results show that the visual quality and evaluation indexes of proposed algorithm outperform other filters for both simulated and real InSAR images. 相似文献
4.
Image quality assessment (IQA) is of fundamental importance for image compression applications. Traditional IQA measures used for Synthetic aperture radar (SAR) image compression do not consider the properties of Human visual system (HVS). Since human beings are the final users in most SAR image applications, the objective evaluation coordinate to human's perception is the most acceptable and practical IQA method. In this paper, we propose a novel objective approach based on image content partition and Neural network (NN) by introducing the HVS and SAR image characteristics. Experimental results demonstrate that the proposed metric correlates well with subjective quality of SAR image compression and outperforms those state-of-art objective models using Structural similarity index (SSIM), Singular value decomposition (SVD) and Visual information fidelity (VIF). 相似文献
5.
6.
7.
8.
This paper proposes a new object-based classification method for Polarimetric synthetic aperture radar (PolSAR) images, which considers scattering powers from an improved model-based polarimetric decomposition approach, as well as the spatial and textural features. With the decomposition, the scattering ambiguities between ori-ented buildings and vegetation are reduced. Furthermore, various contextual features are extracted from the ob ject and incorporated into the K-nearest neighbors (k-NN) based classification. To reduce the feature redundancy, a new Supervised locally linear embedding (S-LLE) dimen-sionality reduction method is introduced to map the high dimensional polarimetric signatures into the most compact low-dimensional structure for classification. Experimental results with Airborne synthetic aperture rada (AIRSAR) C-band PolSAR image demonstrate the superior perfor-mance to other methods. 相似文献
9.
10.
由理想目标散射矢量与待识目标散射矢量的相干系数判据,对待识目标进行检测与同类识别. 利用复旦大学电磁波信息科学教育部重点实验室的散射计算软件BART进行理想目标极化散射计算,构造目标散射矢量,并进行合成孔径雷达(Synthetic Aperture Radar,SAR)成像模拟. 以此目标成像模拟数据作为目标识别样本,对全极化系统Pi-SAR观测海面养殖箱的成像数据,研究其相干系数判据的检测与识别. 结果表明该方法是有效的.
相似文献
11.
12.
13.
14.
极化定标是多极化合成孔径雷达(PolSAR)系统获取真实目标极化散射矩阵的必要步骤。文中针对极化定标过程中存在的极化隔离度距离向空变特性,采用基于无源角反射器的极化定标算法作为仿真工具,对PolSAR系统极化隔离度绝对值及其空变范围对图像中极化隔离度的影响规律进行了分析。分析结果表明:当用于极化修正的极化误差矩阵与PolSAR系统自身极化隔离度不匹配时,极化修正将会使得修正后的图像极化隔离度变差。因此,在进行极化定标时,应当尽可能在定标场沿距离向布设一定间距的多组定标器,从而获取PolSAR系统在整个距离向成像带宽内的极化隔离度拟合曲线,在进行极化修正时对图像中距离向不同的像素点采用曲线中对应位置的极化误差矩阵进行修正,进而得到尽可能接近目标真实极化散射矩阵的估计值。 相似文献
15.
16.
4维合成孔径雷达获取的观测数据在基线-时间平面非均匀分布。若采用传统成像方法来获取目标散射体的高度-速率维像,则因强副瓣存在,成像效果不理想。当信号具有稀疏性时,压缩感知技术能够利用少量的信号投影值就可实现信号的准确或近似重构。然而标准的压缩感知成像方法是针对实数据进行处理,4维合成孔径雷达成像处理的数据为复数据。因此该文提出了一种基于幅度和相位迭代重建的4维合成孔径雷达成像方法。将4维合成孔径雷达高度-速率成像问题转化为目标复散射系数的幅度和相位联合重建问题,通过在成像过程中引入相位信息来改善成像质量。仿真结果验证了该算法的有效性。 相似文献
17.
LIU Xiaojun ZHAO Bo ZHAO Mingming LU Cewu FANG Guangyou 《电子学报:英文版》2008,(4):756-758
A prototype of an airborne wide band coherent radar has been accomplished which can be used for polar ice thickness measurement. The system uses pulse compression and coherent integration techniques and works at the VHF band. Using different transmit power, the radar can operate in both surface-based and airborne applications. The chirp waveform generator was designed by using a Direct digital synthesizer (DDS). A dual-channel receiver was introduced for better performance on the return signals of different layers. Surface-based experiments were done to test the system performace. 相似文献
18.
An intelligent frequency fitting algorithm is presented for continuous-wave radar to track human movers through walls. With the proper fitting dimension, which is usually determined by the practical detection re- quirements, this technique can improve the localization ac- curacy and the tracking performance without introducing too much calculation burden, and more precisely identify different targets even in the frequency ambiguous areas. This technology can also help to match the estimation re- sults to their corresponding targets automatically, which is of great importance to certain urban sensing applications, such as specific target surveillance and tracking. To further improve the detection performance and better identify the weak targets in the presence of strong noise, CLEAN al- gorithm and adaptive filter technology are also involved. Experimental results are provided to illustrate the algo- rithm performance. 相似文献
19.
A Recursive Filter for Despeckling SAR Images 总被引:2,自引:0,他引:2
G R K S Subrahmanyam A N Rajagopalan R Aravind 《IEEE transactions on image processing》2008,17(10):1969-1974
This correspondence proposes a recursive algorithm for noise reduction in synthetic aperture radar imagery. Excellent despeckling in conjunction with feature preservation is achieved by incorporating a discontinuity-adaptive Markov random field prior within the unscented Kalman filter framework through importance sampling. The performance of this method is demonstrated on both synthetic and real examples. 相似文献