基于蚁群优化的近岸影像水边线变化分析方法

由于近岸视频监测技术具有构建成本低、时空分辨率高的特点,近年来已成为海岸动态监测的互补手段。在近岸视频监测中,水边线可作为岸滩边缘位置变化的替代指标,受复杂海滩地形及不规则的波浪及潮汐变化影响,如何从视频图像中准确检测水边线是近岸视频监测所面临的挑战问题之一。本文针对传统图像处理方法在水边线提取中存在的效率不高和抗噪声能力差等问题,将CIELab颜色模型和蚁群优化算法相结合,对台风风暴潮期间石老人海滩的水边线进行提取和定量分析,并与传统算法进行对比。对青岛石老人海滩2011年台风期间的实时影像资料分析结果表明,与传统的提取算法相比,本文提出的方法在数字视频影像的水边线监测应用中可靠性高,并具有良好的细节呈现能力和抗边缘噪声能力,适用于弱边缘水边线的提取。分析结果验证了本方法在极端天气条件下对视频影像中水边线动态变化的自动提取可行性,对构建长时序海滩岸线动态变化影像自动分析系统具有较好的应用价值。     

Depositional environment and hydrocarbon potential of marginal marine sediments of Eocene from western India: A palynofacies perspective

Palynofacies and palynological data from Eocene sediments documents a comprehensive picture of the nature (degraded, structured, non-structured, amorphous etc.) of organic matter, their distribution, and depositional setting for Matasukh lignite mines of Nagaur Basin in western India. Four Sporomorph Eco Groups (SEG) are defined based on the palynological data viz., Upland SEG, Lowland SEG, Coastal SEG and Tidally influenced SEG. Principal component analysis was used to categorize the organic matter into two palynofacies. Palynofacies-A is dominated by brown Phytoclasts (in particular cuticles) and Palynofacies-B is dominated by amorphous organic matter, mainly derived from terrestrially degraded material. In Palynofacies-B there is a reduced frequency of cuticles and high frequency of non-biostructured amorphous phytoclasts in comparison to Palynofacies-A. Further the Integration of Tidal limit index and Phytoclast preservation index suggest that the sediments were deposited in a proximal setting and were regularly influenced by brackish-marine water. The sand bed with current bedding in which the troughs are draped with lignitic clay indicate the tidal wave action. Tyson's ternary diagram indicates the deposition of these sediments in a sub-oxic to dysoxic condition, rich in Kerogen Type-II/III. Thermal alteration index (TAI) shows that the sediments of Matasukh lignite mine have attained maturation (the characteristic value reached by hydrocarbon generating sediments) to generate dry gas as majority of the organic matter is of Type-III Kerogen with few samples yielding Type-II. These sediments were deposited in deltaic plain, in particular, fluvial dominated marginal marine environment.     

基于小波分析的海洋平台实时结构健康监测

由于海洋平台结构长期处于恶劣的海洋环境中,并受到各种载荷的交互作用,结构容易产生各种形式的损伤。因此,对海洋平台进行实时监测有着十分重要的现实意义。以单筒简易导管架平台为例,主要在结构损伤的判定和定位两方面对海洋平台的实时结构健康监测进行研究,结果表明通过对结构响应信号进行小波分析,小波变换系数和小波包能量分布可以很好地定义损伤识别指标。     

结合水平集与光流的序列影像运动分割技术研究

提出一种结合变分水平集分割与变分光流的运动分割方法。该方法将光流能量函数与水平集分割能量函数进行整合形成新的运动分割能量函数,并采用变分方法进行优化。采用无人机序列影像对该运动分割方法进行实验分析,实验结果表明该方法在目标运动位移过大时,既能准确地估计出运动矢量,又能精确地分割出目标区域。     

连续局部阈值分割的阴影检测方法

遥感图像中通常存在大量的阴影,阴影会对图像分割、目标识别造成一定的影响,阴影检测是阴影去除的基础。针对传统Tsai算法准确度上不足,提出了一种改进方法。首先,采用chuang所提出的方法定制了新的比例图,通过对定制比例图进行全局阈值分割将输入图像分为候选阴影点与非阴影点;再对大致阴影图中的每一个候选阴影区进行迭代分割处理来从候选阴影点中挑选出真正的阴影点;剩下的每一个候选阴影点进行fine-shadow判断处理。实验证明,改进算法可以提高阴影检测的准确性。     

Land change attribution based on Landsat time series and integration of ancillary disturbance data in the Athabasca oil sands region of Canada

The Alberta Oil Sands (AOS) is a unique area in Canada undergoing significant disturbance and recovery due to a variety of anthropogenic and natural factors. Accurately quantifying these changes in space and time is important for assessing ecosystem status and trends. In this research, we implemented an approach to combine Landsat time series for the period 1984–2012 with ancillary change datasets to derive detailed change attribution in the AOS. Detected changes were attributed to causes including fire, forest harvest, surface mining, insect damage, flooding, regeneration, and several generic change classes (abrupt/gradual, with/without regeneration) with accuracies ranging from 74% to 100% for classes that occurred frequently. Lower accuracies were found for the generic gradual change classes which accounted for less than 3% of the affected area. Timing of abrupt change events were generally well captured to within ±1 year. For gradual changes timing was less accurate and variable by change type. A land-cover time series was also created to provide information on “from-to” change. A basic accuracy assessment of the land cover showed it to be of moderate accuracy, approximately 69%. Results show that fire was the major cause of change in the region. As expected, surface mine development and related activities have increased since 2000. Insect damage has become a more significant agent of change in the region. Further investigation is required to determine if insect damage is greater than past historical events and to determine if industrial development is linked to the increasing trend observed.     

基于三维GIS的地下电力管线管理系统的设计与实现

电力企业的输配电方式有架空线路和地下电力电缆及管线,它们负责为千家万户传送光明和能量,随着城市电缆化率的提升,地下电缆已变成电力公司重要的基础设施之一,是其赖以生存和发展的"生命线"。本文借助3S技术和传统测绘手段,采集地下电力管网基础数据,开发三维电力管线管理系统,对电缆数据录入建模、绘制各种专题图,实现地下电力管线从规划到建设、从运行到维护的全周期安全管理。     

交通地理信息中基于梯度方向的车道线提取

针对所摄路面影像,本文提出了基于梯度方向的车道线提取方法。车道线上边缘点的梯度方向大体与本车道线垂直,据此我们可以将车道线上的边缘点从所有边缘点中分离出来,再将这些点拟合,得到车道线。实验结果表明,本文方法具有很好的鲁棒性,对复杂路面的车道线提取效果较好。     

基于GF-1多时相波段组合的武汉市土地利用变化检测

GF-1号卫星是中国自主研发的第一颗高分辨率遥感卫星。为分析该卫星影像数据在土地利用变化检测中的应用,本文以武汉主城区为研究对象,选取该地区2014年5月、2015年4月GF-1号卫星遥感影像,采用分类后比较与多时相波段组合直接分类两种方法分别进行试验,将二者实验结果比较分析。结果表明,多时相波段组合直接分类是一种更为有效的变化检测方法。相比分类后比较该方法不仅检测精度提高了将近17%,土地利用变化检测效果也明显改善。另外,对武汉主城区主要土地利用变化类型进行面积统计分析,对武汉主城区建设具有一定的指导意义。     

浅谈室内大长度检测平台设计与应用

介绍了室内大长度检测平台的结构、功能及各检测项目的检测方法,该平台在建设方面达到国内领先水平,能更好地开展全站仪、手持测距仪等计量器具的多项室内项目的检测,确保测绘成果量值的准确和统一。