Composition and genesis of the intrusive rock association of the Magloi magmatic area,the Central Amur region

New geochemical and isotopic-geochronological data are reported on the intrusive association from one of the largest and relatively poorly studied Cretaceous (Aptian-Cenomanian) magmatic zones of the Sikhote-Alin accretionary fold system. The new results and previously published studies were interpreted using concepts of a blocked (terrane) structure of the region and the different geodynamic nature of the magmatic complexes. It was shown that the “transitional” geochemical and geodynamic characteristics of the studied intrusive rocks can be explained in terms of magmatism along the transform continental margin. Additional complicating factors are the composition of the terrane rocks and the change in the geodynamic setting during the formation of the considered magmatic area (114-90 Ma).     

Crop discrimination in Northern China with double cropping systems using Fourier analysis of time-series MODIS data

Crop identification is the basis of crop monitoring using remote sensing. Remote sensing the extent and distribution of individual crop types has proven useful to a wide range of users, including policy-makers, farmers, and scientists. Northern China is not merely the political, economic, and cultural centre of China, but also an important base for grain production. Its main grains are wheat, maize, and cotton. By employing the Fourier analysis method, we studied crop planting patterns in the Northern China plain. Then, using time-series EOS-MODIS NDVI data, we extracted the key parameters to discriminate crop types. The results showed that the estimated area and the statistics were correlated well at the county-level. Furthermore, there was little difference between the crop area estimated by the MODIS data and the statistics at province-level. Our study shows that the method we designed is promising for use in regional spatial scale crop mapping in Northern China using the MODIS NDVI time-series.     

A novel method for enhancement of radiometric resolution using image fusion

The Resourcesat-I satellite is equipped with different types of sensors with varied characteristics. For the effective utilization of the available multi-sensor, multi-temporal, multi-spectral and multi-radiometric data from these sensors, fusion of digital image data has become a valuable technique. Image fusion enhances the information content and helps in better discrimination of various land cover types. The Resourcesat-1 has equipped with three sensors, AWiFS, LISS-III and LISS-IV, which are having identical spectral resolutions, with different spatial, radiometric and temporal resolutions. The spatial resolutions ratio of the data set for merging are required to be maximum of 1:6, where as the data sets (AWiFS and LISS-III) that are used in the current study are having the ratio of 1:2.5 approximately. A novel merging technique is designed, which retains the multi-spectral response of the input data in the output data. The merged data set provides the higher spatial and radiometric resolutions. In order to evaluate the fusion merits quantitatively, all the data sets are digitally classified and studied the output classes for homogeneity and clear discrimination. A comprehensive comparative study is carried out between the fused image and the LISS-III image based on the contingency matrix and the scatter plots, which demonstrates the strength of fused image for discriminating the object classes at 23.5 m spatial and 10-bit radiometric resolutions. The merged data set gives the improved classification accuracy.     

基于小波变换的阈值降噪方法在地震资料处理中的应用

这里主要讨论了小波变换阈值降噪方法的基本原理,并且将广泛使用的通用阈值方法与Birge-Massart阈值方法进行了比较,展现了Birge-Massart阈值选取方法的优越性。通过对模拟数据和实际地震资料的处理结果表明,基于小波变换的Birge-Massart阈值降噪方法对地震信号降噪具有很好的效果。     

一种WiFi距离交会加权融合定位算法

基于距离交会的WIFI室内定位算法受环境的影响,距离反演精度较低导致定位误差较大,不同距离反演模型对定位误差影响特性存在差异。考虑到GPR距离反演模型过度平滑引起定位结果扎堆的缺陷和传统损耗模型反演精度过低引起定位结果误差较大的缺陷,提出一种基于GPR预测模型和损耗模型的加权融合定位算法。实验结果表明:该融合算法能够有效提高定位精度并明显改善基于GPR模型定位算法的定位结果扎堆现象。     

基于GIS的榆林市乡镇地名分布特征研究

利用不同的网络公开地名数据源进行数据融合,获得榆林市乡镇级居民地地名数据,在此基础上,对地名数据进行统计分类,引入地名密度和地名点距离的指标,运用GIS的分析方法,对榆林市乡镇级地名数据进行景观分析。研究得出:榆林乡镇地名从东南向西北部递减,并且呈现出聚集的分布特征;榆林市的自然人文特征直接体现在其主要地名分类的分布上,山水类地名的分布反映了榆林西北部沙漠干旱,东南部黄土丘陵、河流较密的自然特点,姓氏、军事类地名的分布则反映了榆林市的移民文化、多民族混居的民族特色,以及古代军事价值高的特点。     

Worldview-Ⅱ遥感影像的阴影检测方法研究

针对HIS空间变换阴影检测方法仅利用三原色波段数据进行阴影检测而未考虑影像数据之间的相关性及冗余度这一问题,该文结合最佳指数法提出一种适用于多光谱的Worldview-Ⅱ遥感卫星影像阴影检测方法,并引进归一化水体差异指数剔除掉水体的干扰,构建出适用于阴影检测的波段指数模型。实验结果表明,该方法针对Worldview-Ⅱ影像具有普适性,且相对于利用三原色数据进行阴影检测方法能更有效地避免植被信息的干扰,能够精确、快速地检测阴影区域,对后期的阴影去除等研究具有重要的参考价值。     

星载GPS的多目标跟踪数据处理方法

针对测量船外测数据对多个目标进行定轨精度较低的问题,该文提出了星载GPS数据、测量船外测数据的融合处理方法。在多目标测控任务中,航天测量船船载设备获取的外测数据仅包含一个主跟踪目标的测角数据和多个跟踪目标的测距数据,且测角数据精度较低,该文采用由星载GPS数据获取的等效测角数据和由测量船外测设备获取的测距数据进行定轨,经过分析试算,该方法有效弥补了船载外测设备测角数据精度较低的问题,提高了初轨确定的能力以及卫星星间距离的解算精度。     

资源三号卫星高分影像的城市建筑物阴影提取

针对城市高分影像中普遍存在的建筑物阴影严重影响了高分影像的处理和应用问题,该文通过对资源三号卫星(ZY-3)各波段的影像特征进行分析,分别采用基于直方图的阈值分割法、基于主成分变换和HIS变换集成法对阴影提取并对比分析,在此基础上提出了一种基于谱间关系的阴影提取模型。实验结果表明,该文提出的方法能够较好地区分ZY-3影像中的阴影和偏蓝色地物及水体,能够准确地提取城市高大地物阴影。     

水平距离和海拔高度对雷达估测降水影响及订正

以石家庄2006—2008年77次降水过程为例,分析了海拔高度和距雷达站水平距离对定量估测降水的影响,给出了估测降水时反射率因子取值的最佳高度以及距离高度订正值。对比了经验公式法和最优化法分别在有无距离高度订正4种情况下的估测效果,依据估测效果,设计了雷达定量估测降水最佳方案:若反射率因子小于30 dBz,则不进行距离高度订正,仅采用最优化法估测降水;若反射率因子大于30 dBz,则首先对反射率因子进行距离高度订正,然后采用最优化法估测降水。实例检验表明,该方案对单站10 mm·h~(-1)以上的强降水、过程降水量和区域降水量估测效果较好。