结合主动学习和词袋模型的高分二号遥感影像自动化分类     

张金盈  姚光虎  林琳  郭怀轩 《测绘通报》2019,(2):103-107

高分卫星遥感影像空间分辨率的提高，使得地物的光谱和纹理变得更加丰富和复杂，这给遥感影像的自动化分类带来严重挑战。因此，本文提出了一种结合主动学习和词袋模型的高分二号遥感影像分类方法。首先，对研究区域进行多尺度分割，建立影像分割对象集；然后，采用词袋模型构建影像对象的语义特征向量；最后，充分考虑位于分类边界的不确定性样本分布，迭代选择最优样本用于训练支持向量机，用于分类遥感影像。为了验证本文方法的有效性和稳健性，以山东省某市的高分二号遥感影像为试验数据进行了试验分析。结果表明，本文提出的方法可以有效地将研究区域分为水体、地面、植被和建筑物四类，正确率达到90.6%以上。  相似文献   

Estimation of crowd density from UAVs images based on corner detection procedures and clustering analysis     

Ali Almagbile 《地球空间信息科学学报》2019,22(1):23-34

With rapid developments in platforms and sensors technology in terms of digital cameras and video recordings, crowd monitoring has taken a considerable attentions in many disciplines such as psychology, sociology, engineering, and computer vision. This is due to the fact that, monitoring of the crowd is necessary to enhance safety and controllable movements to minimize the risk particularly in highly crowded incidents (e.g. sports). One of the platforms that have been extensively employed in crowd monitoring is unmanned aerial vehicles (UAVs), because UAVs have the capability to acquiring fast, low costs, high-resolution and real-time images over crowd areas. In addition, geo-referenced images can also be provided through integration of on-board positioning sensors (e.g. GPS/IMU) with vision sensors (digital cameras and laser scanner). In this paper, a new testing procedure based on feature from accelerated segment test (FAST) algorithms is introduced to detect the crowd features from UAV images taken from different camera orientations and positions. The proposed test started with converting a circle of 16 pixels surrounding the center pixel into a vector and sorting it in ascending/descending order. A single pixel which takes the ranking number 9 (for FAST-9) or 12 (for FAST-12) was then compared with the center pixel. Accuracy assessment in terms of completeness and correctness was used to assess the performance of the new testing procedure before and after filtering the crowd features. The results show that the proposed algorithms are able to extract crowd features from different UAV images. Overall, the values of Completeness range from 55 to 70 % whereas the range of correctness values was 91 to 94 %.  相似文献   

Statistical analysis of surface urban heat island intensity variations: A case study of Babol city,Iran     

Qihao Weng  Mohammad Karimi Firozjaei  Amir Sedighi  Seyed Kazem Alavipanah 《地理信息系统科学与遥感》2019,56(4):576-604

The urban heat island is considered as one of the most important climate change phenomena in urban areas, which can result in remarkable negative effects on flora, concentration of pollutants, air quality, energy and water consumption, human health, ecological and economic impacts, and even on global warming. The variation analysis of the surface urban heat island intensity (SUHII) is important for understanding the effect of urbanization and urban planning. The objective of this study was to present a new strategy based on the Shannon’s entropy and Pearson chi-square statistic to investigate the spatial and temporal variations of the SUHII. In this study, Landsat TM, ETM+, OLI and TIRS images, MODIS products, meteorological data, topographic and population maps of the Babol city, Iran, from 1985 to 2017, and air temperature data recorded by ground recorder devices in 2017 were used. First, Single-Channel algorithm was used to estimate land surface temperature (LST), and the maximum likelihood classifier was employed to classify Landsat images. Then, based on LST maps, surface urban heat island ratio index was employed to calculate the SUHII. Further, several statistical methods, such as the degree-of-freedom, degree-of-sprawl and degree-of-goodness, were used to analyse the SUHII variation along different geographic directions and in various time periods. Finally, correlation between various parameters such as air temperature, SUHII, population variation and degree-of-goodness index values were investigated. The results indicated that the SUHII value increased by 24% in Babol over different time periods. The correlation coefficient yielded 0.82 between the values of the difference between the mean air temperature of the urban and suburbs and the SUHII values for the geographic directions. Furthermore, the correlation coefficient between the population variation and the degree-of-goodness index values reached 0.8. The results suggested that the SUHII variation of Babol city had a high degree-of-freedom, high degree-of-sprawl and negative degree-of-goodness.  相似文献   

无人机倾斜摄影三维模型在城市雨洪风险评估中的应用     

刘斌  唐雅玲  马晨燕  白少云 《测绘通报》2019,(10):46-50,66

研究城市雨洪风险问题，对提高城市洪涝灾害监测、预报的准确性，以及促进城市防洪决策制定具有重要的意义。鉴于高精度的城市三维模型可以提供丰富地理信息，便于准确分析淹没情况，本文针对当前城市洪涝模型对地形数据的高敏感性，且雨洪风险评估研究的准确性受限于地形数据精度的问题，提出利用无人机倾斜摄影测量技术重建高精度实景三维模型，并结合GIS的空间分析功能，以淹没深度为关键指标进行研究区的雨洪风险评估。通过提取不同重现期下研究区的淹没深度信息，进行可视化渲染实现三维淹没分析，可以直观地看到研究区的淹没情况，作为暴雨内涝风险管理依据，同时对城市规划布局有一定的参考价值。  相似文献   

小区域消费级无人机倾斜摄影像控点布设及建模精度研究   总被引：1，自引：0，他引：1  

桑文刚  李娜  韩峰  赵培华  李玉斌 《测绘通报》2019,(10):93-96

像控点布设是无人机倾斜摄影施测阶段的重要环节，直接决定后期三维实景模型的精度。本文面向校园等小区域环境，利用消费级单镜头多旋翼无人机航摄系统获取影像数据，重点设计了不同像控点布设方案，基于全自动数据处理系统进行空三加密及三维模型的构建，并对模型成果进行精度分析，为实际工作中小区域像控点的布设提供建议和指导。  相似文献   

基于欧拉反褶积法的无人机航磁找矿应用     

乔中坤  马国庆  于平  周文纳  张志厚  焦健  周帅  孟兆海  唐水亮 《吉林大学学报(地球科学版)》2021,51(2):552-560

无人机航磁测量以其高效、安全、低成本等优点逐渐应用到中小面积大比例尺资源勘探领域。本文针对安徽芜湖市三山区22 km²区域构造刻画和找矿前景预测,开展1∶20 000高精度无人机航磁测量工作;推导了欧拉反演求解过程,并分析对比构造指数选取,使用构造指数为0的欧拉反褶积对航磁数据进行反演求解,获得地下磁异常体构造边界解集信息;将其应用到研究区域航磁数据反演,根据反演得到的边界位置和深度信息圈定了18处断裂,并结合异常特征给出了8.7 km²岩浆岩分布区,根据宁芜区域铁矿成矿特点,圈定岩浆分布区及边界为成矿详查区。  相似文献   

无人机遥感技术在甘肃北山地区地质填图中的应用     

戴均豪  薛林福  李忠潭  桑学佳  马建雄 《吉林大学学报(地球科学版)》2021,51(6):1908-1920

甘肃北山地区岩浆岩及变质岩出露广泛,植被稀少,地势平缓,是无人机遥感开展地质填图试验的理想目标区。为解决传统地质填图方法受地形、环境限制和投入高及工作周期长等问题,选取北山长流水地区20 km²化探重点工作区为目标区,利用大疆精灵4专业版无人机采集图像,并采用Photoscan软件合成高分辨率正射影像以及三维模型,建立解译标志,对目标区域进行地质解译,获得比前人1：1万地质图更加精细的地质图。该方法较传统填图方法能够解译出地质体形态、岩脉产状、微小断裂等更详细的地质内容,并能提供划分岩脉期次的证据。  相似文献   

强跟踪抗差自适应滤波算法及其在无人机导航定位中的应用   总被引：1，自引：0，他引：1  

肖业伟  谢小刚 《测绘通报》2021,(4):64-67

针对Sage-Husa自适应滤波算法在无人机导航定位应用中存在滤波发散和定位精度低的问题,本文提出一种强跟踪抗差自适应滤波算法。该算法在Sage-Husa自适应滤波算法基础上,引入强跟踪技术,通过自适应渐消因子降低历史数据对当前滤波的影响,从而抑制滤波发散,增强算法的稳健性;结合量测噪声和系统噪声进行实时估计,并且在估计中加入抗差因子抑制粗差对滤波的干扰,提高定位精度。仿真结果表明,该算法在发生滤波发散和粗差干扰的情况下能够表现出良好的滤波性能,较Sage-Husa算法有更强的稳健性。  相似文献   

面向复杂山地的机载LiDAR与无人机影像融合应用     

高莎  袁希平  甘淑  杨亚复  李霞 《测绘通报》2021,(7):65-69

本文针对LiDAR点云与无人机影像数据特征的优缺点,利用LiDAR点云与无人机DOM影像融合,将影像数据光谱信息赋给LiDAR点云数据,使其不仅具备精准的空间结构信息,还能得到清晰的纹理信息。为验证融合数据应用的可行性与数据提取的准确性,对融合前后的点云数据进行地面点提取与DEM构建。试验表明：将无人机影像的光谱信息赋给LiDAR点云数据,可以实现LiDAR点云数据从四维度表达到七维度的拓展,融合后点云数据具有清晰的纹理信息,地物类型判读更加容易,地面点分离完整;通过DEM模型的对比分析,融合后点云数据构建的DEM模型表达更加接近真实地表。研究结果为多源点云数据的深化应用提供了一定的技术方法支持作用。  相似文献   

三维激光点云和无人机倾斜模型的融合应用     

刘宝华  王智  宋云记 《测绘通报》2021,(6):159-162,165

在对建筑物进行三维实景数据采集时,地面三维激光扫描和无人机倾斜摄影测量是常用的技术手段,通过两种手段获取的数据类型不同,对空间的展示效果及精度也存在差异,特别是在获取建筑物顶部和近地部分的数据各有优劣势,将无人机获取的建筑物顶部数据和地面三维激光扫描获取的近地部分数据进行处理,通过空间多个同名公共点进行转换、匹配,将点云和模型两种数据融合。本文以一个古城门为例进行数据采集,介绍了外业测量和内业处理的方法,并对融合精度进行了分析、探讨。  相似文献