共查询到19条相似文献,搜索用时 375 毫秒
1.
非降水回波识别算法的效果直接影响着雷达数据后续应用(如定量降水估测)的结果,因此对其进行客观定量检验是很重要的。文中所用算法在SWAN系统雷达反射率因子质量控制算法基础上增加了晴空回波识别算法,使用回波延展度因子并增加高度限制来对晴空回波进行识别和去除。使用星载雷达反射率强度数据与非降水回波去除前后的地基雷达数据进行时空匹配,对非降水回波识别算法效果进行客观的直观和定量验证。参照星载雷达观测结果,文中算法针对与降水回波无混叠的超折射回波有很好的识别效果,效果优于存在降水与超折射混叠的情况,当降水回波中存在与超折射回波水平纹理相近的对流降水时,经算法处理后该部分回波会丢失部分信息。针对存在降水与超折射回波混叠的情况,将算法处理前后的地基雷达降水区域反射率因子分别与星载雷达数据进行比较,结果表明经算法处理后的数据更接近星载雷达观测值。评价结果可为算法适用性分析及改进提供依据。 相似文献
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《遥感技术与应用》2019,(5)
非降水回波识别算法的效果直接影响着雷达数据后续应用(如定量降水估测)的结果,因此对其进行客观定量检验是很重要的。文中所用算法在SWAN系统雷达反射率因子质量控制算法基础上增加了晴空回波识别算法,使用回波延展度因子并增加高度限制来对晴空回波进行识别和去除。使用星载雷达反射率强度数据与非降水回波去除前后的地基雷达数据进行时空匹配,对非降水回波识别算法效果进行客观的直观和定量验证。参照星载雷达观测结果,文中算法针对与降水回波无混叠的超折射回波有很好的识别效果,效果优于存在降水与超折射混叠的情况,当降水回波中存在与超折射回波水平纹理相近的对流降水时,经算法处理后该部分回波会丢失部分信息。针对存在降水与超折射回波混叠的情况,将算法处理前后的地基雷达降水区域反射率因子分别与星载雷达数据进行比较,结果表明经算法处理后的数据更接近星载雷达观测值。评价结果可为算法适用性分析及改进提供依据。 相似文献
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非降水回波识别算法的效果直接影响着雷达数据后续应用(如定量降水估测)的结果,因此对其进行客观定量检验是很重要的。文中所用算法在SWAN系统雷达反射率因子质量控制算法基础上增加了晴空回波识别算法,使用回波延展度因子并增加高度限制来对晴空回波进行识别和去除。使用星载雷达反射率强度数据与非降水回波去除前后的地基雷达数据进行时空匹配,对非降水回波识别算法效果进行客观的直观和定量验证。参照星载雷达观测结果,文中算法针对与降水回波无混叠的超折射回波有很好的识别效果,效果优于存在降水与超折射混叠的情况,当降水回波中存在与超折射回波水平纹理相近的对流降水时,经算法处理后该部分回波会丢失部分信息。针对存在降水与超折射回波混叠的情况,将算法处理前后的地基雷达降水区域反射率因子分别与星载雷达数据进行比较,结果表明经算法处理后的数据更接近星载雷达观测值。评价结果可为算法适用性分析及改进提供依据。 相似文献
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基于时频分析的雷达信号滤波方法 总被引:2,自引:2,他引:0
深空目标的雷达回波信号较弱而且受噪声干扰严重,给检测识别工作带来很大的困难;提出了一种时频滤波方法,将基于广义S变换的时频滤波引入到雷达回波信号去噪当中;采用广义S变换对回波信号进行时频分析,利用变换结果求解信号的瞬时频率,并构造了一种时频滤波器.对雷达回波信号进行时频滤波处理并对滤波效果进行分析;仿真结果表明,经滤波后信噪比有较大提高,且很好保留了信号特征。 相似文献
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中值滤波是图像处理中降低椒盐噪声的一种有效手段,其核心是计算当前滤波窗口内所有像素的中值。中值滤波具有稳定性,当一幅图像的像素点被改变时,即使改变的值很大,也不会影响中值滤波的计算结果。滤波窗口遍历整幅图像后,就完成了整幅图像的中值滤波计算。中值滤波算法的关键是定义最优中值算法,以在最短的时间内获取中值。对此,提出并实现了自适应中值算法,能够根据滤波窗口半径和数据类型,自动选择性能最佳的中值算法,并使用ARM NEON指令集进行优化加速。实验结果表明,提出的自适应中值滤波算法较OpenCV的中值滤波算法性能有显著提升,平均性能提升了20%。 相似文献
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为了满足军事与商船航海雷达的仿真要求,提高雷达回波图像仿真的真实感,提出了一种基于扇形带状纹理融合模型的实时扫描仿真方法模拟高真实感的雷达回波图像。该方法以电子航海图(ENC)数据为雷达回波源数据,根据雷达回波形成机理,以扇形带状纹理融合算法替代传统基于像素单元的雷达图像仿真方法,实时生成雷达回波纹理数据,在此基础上,提出雷达回波信号处理仿真模型实现雷达基本功能,包括增益调节、海浪抑制与雨雪抑制等。经实验证明,该方法在雷达回波显示效率和效果上有了明显改善,为解决雷达与电子海图显示与信息系统(ECDIS)模拟提供有效的手段。 相似文献
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雷达影像判读之前需要进行斑点噪声的滤除。本文采用不同的滤波算法对SAR影像进行处理,并分别从定性与定量指标方面对不同算法的滤波效果进行评价对比,从而为SAR影像斑点噪声滤波算法的选择与改进提供指导。 相似文献
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中值滤波是图像处理中常用的滤波方法,其优点是能有效滤除图像中的噪声像素,同时还有一定的保持图像边缘的效果;其缺点是滤波速度慢、图像边缘细节保持效果不理想。在分析中值滤波及其改进算法的基础上,提出了自适应投票快速中值滤波算法(AVMF)。该算法一方面利用图像噪声的特征自适应筛选出需要滤除的噪声像素,另一方面利用滤波窗口的中值元素的特点以及滤波窗口移动的特性,采用完全不排序的投票法快速计算中值。使用Lena图像对AVMF算法进行测试实验,实验结果表明:AVMF同多种中值滤波改进算法比较,不仅能有效滤除噪声和较好地保留图像边缘细节,而且极大地提高了滤波处理速度。 相似文献
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基于图像统计信息的去椒盐噪声算法 总被引:1,自引:0,他引:1
本文主要介绍一种基于图像统计信息的去噪算法,主要利用图像中心像素邻域的均值和方差来消除图像中椒盐噪声的影响。首先,介绍了这种算法的基本原理;然后,分别应用中值滤波算法、自适应中值滤波算法以及本文的算法对有椒盐噪声污染的图像进行滤波,并对实验结果进行比较和分析;最后,文章对这种算法的复杂度进行了计算分析,并将其和中值滤波算法以及自适应中值滤波算法的复杂度作比较,并对这种算法的合理性进行了分析与总结。 相似文献
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This paper deals with a new algorithm applicable to rainfall rate profiling with a rain-attenuating-frequency radar for vertical incidence from an air or space platform. The proposed algorithm is independent from external radar calibration which is especially difficult to perform in airborne or space-borne applications. In addition to backscattering data from raindrops, path-integrated rainfall rate is used to estimate a rainfall rate profile. The path-integrated rainfall rate may be estimated from surface echo attenuation or from brightness temperature measured with an auxiliary microwave radiometer. The performance of the proposed algorithm is evaluated by a computer simulation experiment assuming backscattering and attenuation models of the radar wave due to rain. Then, airborne radar data are analysed with the algorithm to demonstrate its validity. 相似文献
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In this paper, a novel feature extraction approach is proposed for identifying ocean wave characteristics in real time. The algorithm was developed through the integration of the fuzzy C-means clustering algorithm, statistics formulation, short-time Fourier transforms, high frequency radar data processing and window function analysis. This method provides new insight into the detection of ocean wave characteristics and provides a more direct and convenient way to detect changes in ocean wave characteristics than the conventional method. To demonstrate the proposed algorithm, two Wellen radar systems were installed in Samcheok City, Gangwon-do on the East Coast of South Korea. A data set was selected for training the proposed algorithm while three other data sets, not used for the training processes, were used to validate the proposed model. The testing results demonstrate that the proposed algorithm is effective in extracting characteristic features from a variety of ocean waves. It is expected that the proposed system will accurately predict natural hazards and provide adequate warning time for people to evacuate from threatened coastal area. Hence this approach will directly contribute to the reduction of injuries and deaths in natural disasters by supplying near real-time data of the environment around coastal areas. 相似文献
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实时雷达目标回波波形发生器在雷达目标识别中的应用 总被引:3,自引:0,他引:3
在自动目标识别系统(ATR)中往往需要对系统样机进行测试和评估。文中论述了为完成测试而提供信号的目标回波波形发生器,它可以复现实际采集的真实目标的回波,也可以产生由算法提供的目标任意仿真波形,还可以作为普通的波形发生器使用。该波形合成器能够以64MHz的速率从D/A 输出缓存数据,同时提供了1 Hz~4 kHz可编程雷达同步信号,输出合成回波信号,在示波器上可得到完全等同于A 显示器的波形信号,为ATR系统的性能测试提供了可靠的保证。 相似文献
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It is inevitable that the movement of vessels on the sea will be affected by the marine environmental extreme value parameters, such as wind, current, and wave. Driven by these factors, the vessels will produce the following movements: horizontal displacement, heave, and sway. With the shipborne X-band wave measuring radar installed on the vessel, the movements of the vessel will lead to the deviation between the actual position of the radar beam and the places we expect. It will result in an error that the intensity showed on the echo image is not the expected one. A pre-processing algorithm is developed to weaken the influence of the movements of vessel on information inversion of the ocean wave fields imaged by X-band radar. The algorithm utilizes the results of vessel motion model to correct the images from shipborne X-band wave measuring radar. Compared with simulated image sequences influenced by vessel motion, the non-direction wave height spectrum extracted from corrected image sequences matches well with that obtained from the original image sequences uninfluenced by vessel motion. 相似文献
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为了准确识别雷达回波信号中的目标信号,木文将小波变换引入到雷达回波信号处理,对回波信号进行分解、重构以及滤波器设计,去除雷达信号中的噪声,采用MATLAB软件进行系统仿真,结果表明,采用小波变换mallat算法对探地雷达回波信号进行目标识别具有较好的时频分辨率,且可抑制杂波,去除噪声,能很好的识别目标信号,具有很好的应用前景。 相似文献
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基于雷达仿真训练器的地面杂波算法 总被引:4,自引:2,他引:2
在雷达仿真训练器中,地面杂波的计算是比较复杂的。首先它与太多的环境因素有关,建模困难;其次近似计算比较多,误差大。为了解决地面杂波的仿真问题,通过对雷达方程的研究,并针对实际的地形数据,采用微积分的思想,将大面积的无规律的雷达截面积化为小地面的有规律的截面积进行叠加,从而提出了一种建模思路。实验结果也基本符合实际。 相似文献
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This paper describes a recent development in rainfall estimation using satellite-flown and ground-based radars. The Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR), its algorithms and data processing are discussed. The ground validation algorithms and processing of the ground-based radar reflectivity data are explained. The estimates of attenuation-corrected radar reflectivity factor and rainfall rate are given at each resolution cell of the PR. The estimated near-surface rainfall rate and average rainfall rate at the altitudes of 2 km are calculated for each beam position. The TRMM PR profiling algorithm and processing of the PR reflectivity for rain distribution are explained. The TRMM rain products and their geophysical parameters are derived from the measurements from the satellite and ground-based radar. The derived geophysical parameters include vertical rain and hydrometeor profile, rain type, radar back-scatter cross-section, raindrop size distribution, rain gauge rain rates and 5-day and monthly average rain rates. For validation purposes the instantaneous and climatological comparison of the rain estimates from both the Precipitation Radar and ground-based radar at Melbourne, Florida, was carried out on the basis of rain type; i.e. convective/stratiform, vertical structure and rain maps. The error sources in rain profile retrieval from space-borne radar; i.e. the PR and ground-based radar with their algorithm limitations are discussed. A second set of data, this time for an area where no simultaneous ground data are available has also been analysed; the data were chosen for the three-dimensional rain distribution over some parts of India. The issues such as discrimination of rain from surface clutter, calibration accuracy and sensitivity of precipitation radar and discrimination of rain echo from noise are discussed. 相似文献