基于最佳波段组合的高光谱遥感影像分类   总被引：6，自引：0，他引：6  

谭玉敏  夏玮 《测绘与空间地理信息》2014,(4):19-22

针对高光谱数据维数高、数据量大、信息冗余多、波段相关性强等特点,在综合各种数据降维方法的基础上,提出一种基于最佳波段组合的高光谱遥感影像分类方法。以美国印第安纳州地区的AVIRIS数据为例,分析各波段信息量和相邻波段的相关性,利用子空间划分、分段波段指数选择法,进行特征波段的选择;并针对难区分地物类别,应用J-M距离模型对其可分性进行判别,获得最佳波段组合。最后采用支持向量机分类器进行分类。实验结果表明,采用最佳波段组合方法,可以有效地提高高光谱的分类精度。  相似文献   

变形序列小波消噪最佳分解尺度量化指标的确定     

向东  贡建兵 《武汉大学学报(信息科学版)》2014,(4)

小波消噪分解尺度确定的正确与否,直接关系到消噪效果。针对变形序列的消噪,将时序分析建模定价的信息准则与高斯白噪声在小波变换下的特性相结合,提出了用Akaike信息准则作为量化指标,确定小波消噪最佳分解尺度的方法。模拟数据和工程数据的验证结果表明,在Akaike信息准则计算值达到最小时,所确定的分解尺度符合信噪分布规律,达到了较好的消噪效果,实现了作为小波消噪最佳分解尺度确定的量化指标作用,提升了小波消噪在变形数据处理中应用的便捷性。  相似文献   

一种非欧空间城市多层交通最佳路径选择算法     

张开广  孟红玲  巴明廷  孙艳敏  王家耀 《测绘科学》2014,(6):86-89

基于时间距离的多层道路交通测度空间,是一个非欧距离空间。本文根据城市多层交通的实际情况,讨论了基于非欧氏空间的最佳路径选择算法(TSORA)的数据基础、原理及方法,给出了城市多层交通最佳路径计算的方法和步骤,并以洛阳市部分道路为实例,详细讨论了路径选择的计算过程。  相似文献   

An improved wind speed algorithm for “Jason-1” altimeter under tropical cyclone conditions     

QIN Bangyong  ZHOU Xuan  ZHANG Honglei  YANG Xiaofeng  LU Rong  YU Yang  SHI Lijian 《海洋学报(英文版)》2014,33(7):83-88

Rain effect and lack of in situ validation data are two main causes of tropical cyclone wind retrieval errors. The National Oceanic and Atmospheric Administration＇s Climate Prediction Center Morphing technique （CMORPH） rain rate is introduced to a match-up dataset and then put into a rain correction model to remove rain effects on ＂Jason-1＂ normalized radar cross section （NRCS）; Hurricane Research Division （HRD） wind sPeed, which integrates all available surface weather observations, is used to substitute in situ data for establishing this relationship with ＂Jason-l＂ NRCS. Then, an improved ＂Jason-l＂ wind retrieval algorithm under tropical cyclone conditions is proposed. Seven tropical cyclones from 2003 to 2010 are studied to validate the new algorithm. The experimental results indicate that the standard deviation of this algorithm at C-band and Ku-band is 1.99 and 2.75 m/s respectively, which is better than the existing algorithms. In addition, the C-band algorithm is more suitable for sea surface wind retrieval than Ku-band under tropical cyclone conditions.  相似文献   

Biological identification and determination of optimum growth conditions for four species of Navicula     

ZHAO Xiaobo  PANG Shaojun  LIU Feng  SHAN Tifeng  LI Jing 《海洋学报(英文版)》2014,33(8):111-118

Four species in the genus Navicula were isolated using the serial dilution method. Based on scanning electron microscopy(SEM) and sequence comparisons of two segments of genes(small ribosomal subunit and large subunit of Rubisco), the species were identified as Navicula perminuta, N. pseudacceptata, N. vara, and N. rhynchocephala. Based on phylogenetic analysis and culture trials, there was a close relationship between N. perminuta and N. vara. Growth of these species was evaluated using measurements of optical density at 680 nm(OD680) under various environmental factors. Results showed that the optimum culture conditions were 25℃, 50–100 μmol photons m-2 s-1, pH 8.0, and salinities from 25 to 30. However, the favorable salinity for N. perminuta was surprisingly high at 35. Nutrient requirement analysis demonstrated that growth of Navicula depended on the availability of SiO32-. Their relative growth rates(RGR) peaked at the highest tested level(0.25 mmol/L). The optimal concentrations of NO3- and PO43- were 3.6 mmol/L and 0.18 mmol/L, respectively. Culture of these Navicula species for abalone or sea cucumber aquaculture should take these factors into consideration.  相似文献   

White spot syndrome virus inactivation study by using gamma irradiation     

Marzieh Heidareh  Farahnaz Motamedi Sedeh  Mehdi Soltani  Saeed Rajabifar  Mohammad Afsharnasab  Aghil Dashtiannasab 《中国海洋湖沼学报》2014,32(5):1024-1028

The present study was conducted to investigate the effect of gamma irradiation on white spot syndrome virus(WSSV). White spot syndrome virus is a pathogen of major economic importance in cultured penaeid shrimp industries. White spot disease can cause mortalities reaching 100% within 3–10 days of gross signs appearing. During the period of culture, immunostimulant agents and vaccines may provide potential methods to protect shrimps from opportunistic and pathogenic microrganisms. In this study, firstly, WSSV was isolated from infected shrimp and then multiplied in crayfish. WSSV was purified from the infected crayfish haemolymph by sucrose gradient and confirmed by transmission electron microscopy. In vivo virus titration was performed in shrimp, Penaeus semisulcatus. The LD50 of live virus stock was calculated 10 5.4 /mL. Shrimp post-larvae(1–2 g) were treated with gamma-irradiated(different doses) WSSV(10 0 to 10-4 dilutions) for a period of 10 days. The dose/survival curve for irradiated and un-irradiated WSSV was drawn; the optimum dose range for inactivation of WSSV and unaltered antigenicity was obtained 14–15 kGy. This preliminary information suggests that shrimp appear to benefit from treatment with gammairradiated WSSV especially at 14–15 KGy.  相似文献   

C波段偏振雷达几种系统误差标定方法对比分析   总被引：1，自引：0，他引：1  

胡志群  刘黎平  吴林林 《高原气象》2014,(1)

通过介绍几种标定C波段偏振雷达差分反射率因子ZDR和水平反射率因子ZH系统误差常用方法的原理,利用两部相同型号的可移式C波段双线偏振雷达(POLC)在云南、安徽等地的观测数据,对这些方法进行了检验和对比分析。结果表明,ZDR的标定方法中,太阳法由于偏振雷达水平与垂直方向两个接收机在较弱的信号下很难保持一致性,目前实际应用比较困难;垂直指向法要求雷达天线必须达到90°仰角,机械上有所制约;仰角法要求探测到非常均匀的雨区,在时间与空间上极难满足;地物引起的ZDR变化,在统计上无任何规律可循,因此,地物法也基本上可以排除应用于实际;干雪的ZDR并不完全等于0 dB,并且需要知道0℃层的高度,0℃层以上满足信噪比(signal to noise ratio,SNR)条件的数据较少,并且水凝物相态难以确定为干雪,因而干雪法有着一定的局限性;微雨滴法理论清晰、结论可信,不需要专门的扫描方式,能够从正常的体扫观测中得到大量的满足SNR、ZH等阈值条件的数据,提供较为准确的ZDR系统误差估计,因此,微雨滴法是一种利用气象目标进行ZDR系统误差估计较好的方法。进一步分析ZH标定的自约束法的结果表明,自约束法能够大致地验证偏振雷达ZH标定是否正确,但是,其用于ZH标定时,对偏振参量数据质量要求较高,并且约束关系的系数也有待进一步验证。  相似文献   

27°斜模式采样及其遥感图像复原研究     

王京萌  张爱武  孟宪刚  赵宁宁 《测绘通报》2014,(4)

针对不能确定斜模式采样的倾斜角度,与后期纠正处理带来的锯齿、混叠等效应,以及斜模式采样在采样过程中产生的混叠等问题,设计并实现了27°斜模式采样方式以降低采样后处理产生的锯齿等降质效应,通过分析线阵CCD采样过程中混叠的成因,将倒易晶胞应用于复原实际斜采样的遥感图像中。截止频率评价图像的分辨率证明:本文方法复原的图像较常规采样图像的分辨率提高了2.26倍。27°斜模式采样与倒易晶胞的复原方法可以应用到无高分辨率参考图像的遥感图像复原中,并可以减少混叠,使复原图像有更好的效果。  相似文献   

基于局部区域梯度最小点的遥感图像镶嵌算法     

程红  郑悦  孙文邦 《国土资源遥感》2014,(1)

寻找最佳拼接缝是遥感图像镶嵌中的重要环节。目前寻找最佳拼接缝的算法大多只考虑到对应像素灰度的差异最小,却忽略了保留目标的完整性。为此,提出一种基于局部区域梯度最小点的最佳拼接缝寻找算法。该算法用梯度表示图像中灰度变化的快慢,梯度值小说明灰度变化较为平缓,据此在图像重叠区域中逐行选取最小梯度值点的连接线作为最佳拼接缝。同时,针对强制改正法易在列方向上产生横向带状效应的问题,提出一种改进的"差值拼接缝消除算法"。实验结果表明,用该文算法确定的最佳拼接缝有效地避开了梯度变化较大的区域,既有效地绕开目标的边缘,又保留了目标的完整性;改进的差值拼接缝消除算法还有效地避免了灰度差较大情况下的横纹现象,使镶崁图像的色调过渡更为平滑,视觉效果得到改善;且算法的运行速度更快,具有一定的可行性和有效性。  相似文献   

非欧氏空间中最佳路径算法研究     

张开广  孟红玲  巴明廷  孙艳敏 《测绘科学技术学报》2013,30(1):83-86

基于时间距离的城市道路交通测度空间是一个非欧氏距离空间。根据城市道路交通的实际情况,设计了基于非欧氏距离空间的最佳路径选择算法。因为道路路口的转向时间消耗是路径时间消耗的重要组成部分,算法在路径经过的道路路口处,根据离开路口的方位角定义了路口的虚拟状态。合并考虑路段和路口转向的时间消耗,通过计算起点到虚拟状态的累计时间,完成了最佳路径的选择。算法是一个多阶段决策过程,通过递推方法来实现;并通过一个实例证明了算法的有效性。  相似文献