热红外与可见光数据的云边缘高度匹配

高分辨率数据中云高度的差异性突显,特别是边缘处高度在云阴影识别和地表辐射估算等方面成为需要考虑的重要因素。热红外数据获取云高度分辨率较低、缺乏细部差异性特征,为解决这一问题,首先将对应的热红外和可见光数据进行特征点配准,再将基于热红外数据计算的云高度重采样至高分辨率,然后以基于欧式距离变换的围线搜索方法及距离加权将热红外云边缘高度匹配至对应的可见光图像,最后根据云阴影的相似度匹配方法确定真实云高度。结果表明,算法在遵循热红外云高信息分布变化规律的同时,可以得到较准确的高分辨率云边缘高度,一定程度上解决了热红外技术获取云高在分辨率上的局限,扩展了其在云高反演方面的作用。     

基于地形三维阴影图的等高线数据库后处理的质量控制方法研究

等高线矢量化完成后的数据质量检查是等高线数据库建设的关键环节。本文提出了一种简便、实用的等高线数据库后处理的质量控制方法。文章深入分析了天山公路GIS等高线数据库建设过程中错误的表现形式,分析了错误来源,并基于地形三维阴影图和地形图快速检测和修改这些错误,保证了等高线数据库的质量和精度。对其他GIS工程基础地理信息数据库建设具有参考价值和借鉴意义。     

利用ASTER卫星立体像对提取喀斯特数字地形模型——以广西大化高峰丛深洼地喀斯特地貌为例

ASTER卫星立体像对已经被成功地用于提取全球数字地形模型（DEM）,其有效性已经在不同类型的非喀斯特地貌区域得到验证。和一般地貌相比,喀斯特地形,特别是中国南方喀斯特,具有自己独特的形态特征。能否从ASTER影像中精确地提取喀斯特地貌DEM目前尚未见到有任何报道。本文利用ASTER影像成功地提取了广西大化地区高峰丛深洼地的喀斯特地貌DEM,并且将提取结果与同一地区1∶5万地形图控制点的高程和4个剖面的高程变化进行了对比。研究区内绝大部分区域是喀斯特地貌,但在其西北部有一舌状砂岩地貌分布,从而提供了一个很好的喀斯特和非喀斯特地貌DEM精度对比的机会。本文的研究结果表明,从ASTER影像提取出来的砂岩地貌的DEM均方根误差要小于喀斯特地区,表明从ASTER影像中能更有效地提取非喀斯特地貌的DEM。相比之下,提取得到的喀斯特DEM精确度则稍差。究其原因主要是因为研究区内独特的高峰丛深洼地地形形态。由于峰丛地形的阴影在构成立体像对的两幅影像（nadir-looking和aft-loo-king）上的大小和形态差异很大,导致了DEM生产过程中两幅影像不能精确配准,从而产生比较大的误差。相比之下,砂岩地区地貌相对比较平坦,地形阴影大小和形态在两幅影像上差别不大,故而能得到精度比较高的数字地形模型。本文研究结果同时还表明适当增加地面控制点能在一定程度上改善提取出来的喀斯特地貌DEM的精度。尽管提取的数字地形模型精度稍低,其均方根误差仍然远远小于该地区峰丛和洼地个体体量。因此本研究认为从ASTER立体像对提取的数字地形模型可广泛用于喀斯特地貌形态特征研究。     

MAPPING SOLAR ACCESS IN HIGH RELIEF AREAS FOR REGIONAL ENERGY PLANNING*

Access to the sun for space heating of structures is controlled, in part, by topographic shadowing in high-relief regions. A simple graphic procedure is presented for mapping shadows on topographic maps for any date and time of day. Comparisons of computed shadows and shadows measured from aerial photography confirm that the mapping procedure is reliable and accurate. Use of the procedure as a solar access inventory tool is illustrated in an area of the Green Mountains, VT.     

A Small War,Gallipoli 1915. He Who is Above Sees All: An Early Use of Aerial Photography in Terrain Analysis

Abstract

When Lord Kitchener ordered Sir Ian Hamilton in 1915 to command land operations on Gallipoli he gave him a solitary old One Inch map and denied him any air forces. When Winston Churchill had earlier sent the Royal Navy to break through to the Black Sea, he had ensured that the Royal Naval Division withdrawn from fighting on the Western Front was accompanied by a Naval Air Squadron as its forward reconnaissance element. Ernest Dowson, the Surveyor General of Egypt, appointed to provide local mapping support, soon convinced the Naval pilots of the value of air photography taken systematically to meet his map-making requirements. In September 1915 Dowson wrote a Secret technical report demonstrating for the first time to British Commanders the practicality of mapping from specified aeroplane photographs of the operational area.     

关于应力触发和应力影概念在地震预报中应用的一些思考

应力触发和应力影概念及其在地震预报中的应用,是学术界关注的热点,尚有一系列需要研究的问题。例如初始应力场的确定,合理流变模型的选取和计算,孔隙压力的变化和影响,断层强度随时间的变化等。特别在估计应力场变化时,人们现今只注意到大地震对应力场造成的变化。一些新的观测事实表明,大量的小地震效应,慢地震的效应和无震滑动的效应,也不容忽视。定量考虑它们的效应,是今后应力触发和应力影研究中应该注意的课题。     

基于谱分析的低频阴影检测技术

基于小波变换的瞬时谱分析方法,克服了传统傅立叶时频转换时的时窗问题,提高了地震资料频域内的分辨能力。通过谱分析方法的比较,介绍了瞬时谱分析方法比传统傅立叶变换的改进效果,以及利用瞬时谱分析方法在分频数据体低频部分识别富气层下方的低频阴影来综合预测储层的横向展布特征和含气性异常的检测。研究实例表明低频阴影检测技术可以作为一种储层预测和油气检测的有效辅助方法。     

The effects of Dissolution–Precipitation Creep on quartz fabrics within the Purgatory Conglomerate,Rhode Island

Quartz Crystallographic Preferred Orientation (CPO) patterns are most commonly a result of deformation by dislocation creep. We investigated whether Dissolution–Precipitation Creep (DPC), a process that occurs at lower differential stresses and temperatures, may result in CPO in quartz. The Purgatory Conglomerate is part of the SE Narragansett basin where strain intensity increases from west to east and is associated with top-to-the-west transport and folding during the Alleghanian orogeny. Within the Purgatory Conglomerate, DPC led to quartz dissolution along cobble surfaces perpendicular to the shortening direction, and quartz precipitation in overgrowths at the ends of the cobbles (strain shadows), parallel to the maximum extension direction. Quartz c-axis orientations as revealed by Electron Backscatter Diffraction (EBSD) methods were random in all analyzed domains within the cobbles and strain shadows irrespective of the intensity of strain or metamorphic grade of the sample. Quartz dissolution probably occurred exclusively along the cobbles' margins, leaving the remaining grains unaffected by DPC. The fact that quartz precipitated in random orientations may indicate that the strain shadows were regions of little or no differential stress.     

视频序列图像中运动目标检测与阴影去除

提出了一种新的基于柯西分布的光照模型(shading model,SM)变化检测方法。在一种快速动态背景图像初始化的基础上,建立了Gaussian统计背景模型;基于使用统计假设检验方法检测变化区域的结果,利用YCbCr颜色空间的亮度、颜色信息,识别和消除视频序列图像中的阴影和反光等。试验表明,该文所提出的方法可以承受整体或局部的、缓慢或突然的背景光线变化,以及由场景背景中小的背景扰动、阴影或反光导致的噪声,可以较精确地检测背景目标,改善了SM方法在较暗区域的目标检测效果。