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DSSS中抑制窄带干扰的实时频域滤波技术 总被引:5,自引:2,他引:3
针对直接序列扩频通信中大功率的窄带干扰,研究改进了基于频域的干扰抵消算法,对影响算法的几个因素:时窗函数、重叠算法及干扰信号带宽做了理论分析和仿真。仿真表明,该算法有效地提高了系统的抗干扰性能。 相似文献
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本文着重介绍下视景象匹配系统的定位原理、基本组成、影响匹配性能因素分析与性能估计,以及提高匹配性能的方法,最后指出研制下视景象匹配系统的技术关键。 相似文献
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无人驾驶飞机飞行航迹的显示是现代无人机测控系统的组成部分之一。航迹显示的实时性和整体滤波效果直接影响对测控系统的评价。本文在分析航迹测量过程中的误差及其引入过程的基础上,提出了简化自适应卡尔曼滤波和变参数惯性滤波的方法。通过实测数据的滤波表明应用相当成功。 相似文献
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针对远距离压制干扰下机动目标跟踪问题,分析了远距离大功率压制干扰对于雷达探测及测量精度的影响,引入新的量测模型模拟雷达在压制干扰下由于探测概率下降出现的目标暂消现象,并利用去相关无偏量测转换方法将球坐标下的量测转换到直角坐标系下.在此基础上,基于自适应联邦滤波的思想建立了雷达压制干扰下的机动目标跟踪算法.仿真结果表明,... 相似文献
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文中介绍了自适应滤波算法的原理和干扰抵消器工作原理,并将LMS算法、NLMS算法和变步长LMS算法分别应用在了干扰抵消器中进行了仿真。仿真的结果表明,三种自适应算法运用到了干扰抵消器中,都可以很好地滤除干扰,提取有用信号。其中运用了变步长LMS算法的干扰抵消器无论在收敛速度和滤波性能上,都要强于其他两种算法。 相似文献
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针对传统Retinex算法采用高斯滤波估计图像的照射分量易产生边缘模糊,不能有效去除脉冲噪声且处理后的图像颜色易失真等问题,提出一种基于三边滤波的Retinex图像去雾算法。该算法利用三边滤波器估计图像的照射分量,三边滤波器继承了双边滤波器既可以有效降低图像加性高斯噪声又可以保持图像边缘细节的特性,同时又解决了双边滤波器与高斯滤波器不能有效滤除脉冲噪声,易产生伪边缘等问题。为验证该算法的有效性,采用5种不同的客观评价参数对处理后的图像进行评价。实验证明,该算法能有效地改善雾天图像的退化现象,提高图像的清晰度。 相似文献
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Multi-focus image fusion is the activity of synthesizing multiple images of different focusing settings to construct a fully focused image. Many of the latest methods for image fusion rarely consider the structural differences between the guidance image and the input image, and do not retain well the important source image features while producing a fully focused image. To address this issue, a method exploiting a combination of static and dynamic filters (SDF) is proposed herein. This combination has good edge smoothing characteristics and strong robustness against artifacts such as gradient inversion and global strength migration. First, SDF is utilized in order to decompose the source image into structure and texture layers. Secondly, a morphological gradient operator filter is used to calculate the significance map of different levels of the source. Thirdly, the maximum pixel value of the significance map is used to construct the binary decision graph of the two source images. Then, the structure and texture layers are fused with the aid of the binary decision graph, and subsequently the final fusion image is created by combining the fused structure layer and texture layer. This process ensures that spatial consistency is preserved. Tests on grayscale and color multi-focus image sets show that the proposed method has better performance than that of any of the existing methods according to both objective and subjective evaluation. 相似文献
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基于遗传算法的导航实时图像匹配算法 总被引:1,自引:0,他引:1
由于一般图像匹配算法均采用全局搜索法,耗时较大,为满足景象匹配辅助导航系统实时性的要求,提出了一种将遗传算法和加权Hausdorff距离算法相结合的图像匹配算法,利用遗传算法的非遍历搜索机制,迅速收敛到全局近似最优解,提高了匹配搜索的快速性.同时,提出了一种基于特征图像分支点提取的加权Hansdorff距离图像匹配算法,并给出了相应的权值求解公式,利用加权Hausdorff距离作为遗传算法的适应度函数,能够明显减少匹配搜索的计算量,提高匹配结果的精度.仿真分析表明,将遗传算法和加权Hausdorff距离算法相结合的图像匹配算法能够很好地满足景象匹配辅助导航系统的实时性和精度要求. 相似文献
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本文对点运算的图像增强算法和红外滤波增强算法进行探讨和研究,包括灰度变换和直方图修正,平滑滤波和锐化滤波。平滑滤波能够有效的对噪声进行平滑处理,达到去除噪声、提高图像质量的目的。锐化滤波中的拉普拉斯模板算法能够对图像的轮廓线进行有效的增强,图像的视觉效果得到了很大的提高。但是该算法处理后的图像视觉效果生硬、不够柔和,同时也会对噪声进行增强。以上方法的单独应用只能针对图像的某些特征进行处理,为了能够提高图像的综合质量,我们需要对以上算法的综合应用进行研究。 相似文献
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Sparse representation (SR) has been widely used in image fusion in recent years. However, source image, segmented into vectors, reduces correlation and structural information of texture with conventional SR methods, and extracting texture with the sliding window technology is more likely to cause spatial inconsistency in flat regions of multi-modality medical fusion image. To solve these problems, a novel fusion method that combines separable dictionary optimization with Gabor filter in non-subsampled contourlet transform (NSCT) domain is proposed. Firstly, source images are decomposed into high frequency (HF) and low frequency (LF) components by NSCT. Then the HF components are reconstructed sparsely by separable dictionaries with iterative updating sparse coding and dictionary training. In the process, sparse coefficients and separable dictionaries are updated by orthogonal matching pursuit (OMP) and manifold-based conjugate gradient method, respectively. Meanwhile, the Gabor energy as weighting factor is utilized to guide the LF components fusion, and this further improves the fusion degree of low-significant feature in the flat regions. Finally, the fusion components are transformed to obtain fusion image by inverse NSCT. Experimental results demonstrate the more competitive results of the proposal, leading to the state-of-art performance on both visual quality and objective assessment. 相似文献
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