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Joanne Poon Clive S. Fraser Zhang Chunsun Zhang Li Armin Gruen 《The Photogrammetric Record》2005,20(110):162-171
The growing applications of digital surface models (DSMs) for object detection, segmentation and representation of terrestrial landscapes have provided impetus for further automation of 3D spatial information extraction processes. While new technologies such as lidar are available for almost instant DSM generation, the use of stereoscopic high-resolution satellite imagery (HRSI), coupled with image matching, affords cost-effective measurement of surface topography over large coverage areas. This investigation explores the potential of IKONOS Geo stereo imagery for producing DSMs using an alternative sensor orientation model, namely bias-corrected rational polynomial coefficients (RPCs), and a hybrid image-matching algorithm. To serve both as a reference surface and a basis for comparison, a lidar DSM was employed in the Hobart testfield, a region of differing terrain types and slope. In order to take topographic variation within the modelled surface into account, the lidar strip was divided into separate sub-areas representing differing land cover types. It is shown that over topographically diverse areas, heighting accuracy to better than 3 pixels can be readily achieved. Results improve markedly in feature-rich open and relatively flat terrain, with sub-pixel accuracy being achieved at check points surveyed using the global positioning system (GPS). This assessment demonstrates that the outlook for DSM generation from HRSI is very promising. 相似文献
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马春笋 《云南地理环境研究》1992,4(2):30-38
在社会主义市场经济下,探讨中国区域政策的走向有着深远的现实意义。本文从历史分析入手,用大量事实证明了中国区域政策演变的实质就是倾斜度的提高。倾斜度加大虽然促进了中国经济的发展,但同时也带来了一系列问题,对此,作者提出制定中国区域政策必须坚持适度倾斜的原则,开发优势区位潜力。 相似文献
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宁芜、庐枞火山岩地区发育有“玢岩”式各种类型的铁矿床。在其氧化带中发现有蓝铁矿、绿松石和银星石等磷酸盐矿物。研究认为它们是磷灰石风化作用形成的表生矿物。 相似文献
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目的：分析反复呼吸道感染（RRTI）患儿维生素A、D、K水平特点，并探讨其与中医证型的相关性，为RRTI的防治提供新的思路。方法：选取228例3～7岁RRTI患儿为研究对象，收集其临床资料并进行中医辨证分型，并纳入74 例同年龄段的正常儿童作为对照组。比较2组儿童的维生素A、D、K水平；并采用Logistic回归分析探讨RRTI组儿童维生素A、D、K水平与中医证型的关系。结果：RRTI患儿的维生素A、D水平低于正常组儿童（P＜0.01）；维生素A水平与肺脾气虚型RRTI、维生素D水平与脾肾两虚型RRTI、维生素K水平与胃肠积热型RRTI的发病率呈负相关。结论：RRTI患儿的维生素A、D水平偏低；且维生素A、D、K水平与RRTI中的某些中医证型存在相关性。 相似文献
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