Investigation of Image Fusion Between High—Resolution Image and Multi—Spectral Image     

LlPingxiang WANGZhijun 《地球空间信息科学学报》2003,6(2):31-34

On the basis of a thorough understanding of the physical characteristics of remote sensing image,this paper employs the theories of wavelet transform and signal sampling to develop a new image fusion algorithm.The algorithm has been successfully applied to the image fusion of SPOT PAN and TM of Guangdong province, China The experimental results show that a perfect image fusion can be built up by using the image analytical solution and reconstruction in the image frequency domain based on the physical characteristics of the image formation.The method has demonstrated that the results of the image fusion do not change spectral characteristics of the original image.  相似文献   

人口密度的空间连续分布模型   总被引：21，自引：0，他引：21  

吕安民  李成名  林宗坚  史文中 《测绘学报》2003,32(4):344-348

分析了常用的表示人口分布的方法,并指出了其不足的地方,提出了模拟人口空间分布的必要性,同时提出了模拟人口空间分布的思路。将研究区域划分为一定分辨率的格网,用核心估计方法将人口密度估计值分配到每个格网上,每个格网上的人口是均匀分布的,随着格网分辨率的提高,就可以模拟出符合人口详细分布的人口密度空间连续分布模型,并通过实验说明该方法是可行的。  相似文献   

甘肃北山地区南金山金矿床隐爆角砾岩体的发现及成矿规律研究   总被引：5，自引：1，他引：5  

沈远超  申萍  曾庆栋  刘铁兵  李光明 《矿床地质》2006,25(5):572-581

地质研究发现,南金山金矿区出露的下石炭统白山组上岩组的部分岩石为隐爆角砾岩,其中厚层-块状变花岗质砂砾岩为隐爆岩浆角砾岩,厚层-块状变凝灰质砂砾岩为隐爆凝灰角砾岩。隐爆角砾岩体呈近EW向带状分布,隐爆岩浆角砾岩分布于岩体中部,构成岩体的内带,隐爆凝灰角砾岩对称分布于岩体南北两侧,构成岩体的外带。经矿床地质研究,提出了新的认识,认为该矿床的形成受隐爆角砾岩体及隐爆断裂构造的控制,金矿体分布于隐爆角砾岩体外带的隐爆凝灰角砾岩及隐爆断裂中;提出了隐爆角砾岩体外带成矿、对称成矿和双层成矿等3条矿体分布规律。采用EH-4连续电导率成像仪进行了深部地球物理测量,测量结果验证了隐爆角砾岩体控矿及其成矿规律。  相似文献   

线性矩法估计参数的保证修正值系数B的推求   总被引：3，自引：0，他引：3  

刘攀  郭生练  胡安焱 《水文》2006,26(6):27-29

在设计洪水的抽样误差估计中,采用保证修正值系数B方法估计均方差简单易用。应用线性矩法估计频率分布曲线的参数,有较好的无偏性和有效性,具有一定的应用前景。目前线性矩法的B值诺模图尚未确定,给用线性矩法确定参数时估计抽样误差带来了难度与不便。采用统计试验,分析了离差系数、偏态系数和样本长度对B值的影响,结果表明线性矩法估计参数时仍可采用保证修正值系数B值诺模图方法来估计抽样误差,并推求了不同偏态系数、设计频率情形下的B值,制成了线性矩法的B值诺模图备用。  相似文献   

桂林市2005年6月连续性暴雨的季风扰动及动力条件分析     

蒋丽娟  李向红  薛荣康 《气象研究与应用》2006,27(2):1-4

通过对2005年6月连续性暴雨过程发生前后的天气形势和物理量场进行分析,发现暴雨发生时,与500hPa螺旋度、涡度及850hPa水汽通量配置较好。暴雨前期低空急流加强,表现在暴雨发生前850hPa沿110°E有V分量的增长。另外,可通过对T 213物理量预报场的分析,判断未来暴雨发生的可能性。  相似文献   

Angular resolution of terrestrial laser scanners   总被引：5，自引：0，他引：5  

Derek D.  Lichti  Sonam  Jamtsho 《The Photogrammetric Record》2006,21(114):141-160

Knowledge of a laser scanner's spatial resolution is necessary in order to prevent aliasing and estimate the level of detail that can be resolved from a scanned point cloud. Spatial resolution can be decoupled into range and angular components. The latter is the focus of this paper and is governed primarily by sampling interval and laser beamwidth. However, emphasis is often placed on one of these—typically sampling interval—as an indicator of resolution. Since both affect the resolution of a scanned point cloud, consideration of only one factor independent of the other can lead to a misunderstanding of a system's capabilities. This will be demonstrated to be inappropriate except under very specific conditions. A new, more appropriate resolution measure for laser scanners, the effective instantaneous field of view (EIFOV), is proposed. It is derived by modelling the shift variance of the equal angular increment sampling process, laser beamwidth-induced positional uncertainty and observed angle quantisation with ensemble average modulation transfer functions (AMTFs). Several commercially available terrestrial laser scanner systems are modelled and analysed in terms of their angular resolution capabilities using the EIFOV.  相似文献   

高密度空间采样地震数据特点分析   总被引：3，自引：0，他引：3  

蔡希玲  刘学伟  邓春艳  吕英梅 《应用地球物理》2006,3(1):48-54

中国陆相沉积盆地的地质结构复杂,储层岩性的多变,需要有高精度的勘探方法。高密度空间采样是提高地震勘探精度的一项新技术。本文简要说明了点激发和点接收技术,分析高密度空间采样的野外工作方法,介绍了Gijs j．o．Vermeer提出的对称采样原理,从波场连续性的角度探讨了高密度空间采样技术。重点分析高密度空间采样数据的特点, 即:高密集的初至波有利于近地表结构的调查,可提高静校正的精度;小偏移距、小点距接收增加了浅层的有效覆盖次数,提高浅层反射的成像精度; 对规则噪声可实现无假频采样,室内的噪声分析和噪声压制的精度随着提高;高密度采集使波场连续性增强,使得各种数学变换的精度提高,有利于不同波场的分离。最后指出高密度空间采样地震勘探技术的难点在于室内数据处理,针对海量数据的分析和处理方法还需要进行深入细致的研究工作。  相似文献   

The formation evaluation tool and its application in offshore China     

Liu Jianxin Zhang Conghui Pang Xishun 《应用地球物理》2006,3(1):62-67

The Formation Evaluation Tool （FET） introduced in the paper represents a new generation of formation evaluation systems developed and manufactured by China Oilfield Services Limited （COSL）, CNOOC, using a FET technology transfer from Crocker Research, Australia. The system has been applied successfully in the Bohai Sea and South China Sea. For instance, a multilayered oil and water system has been confirmed with the aid of accurate formation pressure tests, even in very thin beds and edge water reservoirs, overcoming the difficulty of determining this kind of oil-water and gas-water contacts. Moreover, the FET pumping and real-time fluid monitoring function allows acquiring a true sample of formation fluid unpolluted by drilling mud which plays an important role in determining the fluid properties of the target stratum and analyzing the fluid component. The principles and purpose of the Formation Evaluation Tool （FET） will be briefly introduced and successful examples of the application of the technology will be described in detail in this paper.  相似文献   

Variations of near-surface atmospheric CO₂ and H₂O concentrations during summer on Muztagata     

Xu Baiqing  Yao Tandong  Lu Anxin  Guo Xuejun  Liu Xianqin  Li Zhen 《中国科学D辑(英文版)》2006,49(1):18-26

Expeditions during the summers of 2002 and 2003 implemented continuous monitoring of near-surface (2 m height) atmospheric CO₂ and H₂O concentrations at the 4500 m elevation on Muztagata. The resultant data sets reveal a slight decrease of CO₂ concentrations (of about 5 μmol·mol^-1) and changes in the diurnal variations from the end of June to the middle August. The daily maximum CO₂ concentrations occur between 02:30-05:30 AM (local time) and the minimum levels occur between 12:00-15:30 PM. The atmospheric CO₂ concentrations in the summer of 2002 were around 5 μmol·mol^-1 lower than those during the same period of 2003, whereas the diurnal amplitude was higher. In contrast, we found that the daily mean atmospheric H₂O content in 2003 was much lower than that in 2002 and there exists a striking negative correlation between CO₂ and H₂O concentrations. We therefore suggest that the near-surface atmospheric CO₂ concentration is affected not only by photosynthesis and respiration, but also by the air H₂O content in the glaciated region around Muztagata.  相似文献   

Flux contribution of coherent structures and its implications for the exchange of energy and matter in a tall spruce canopy   总被引：2，自引：5，他引：2  

Christoph Thomas  Thomas Foken 《Boundary-Layer Meteorology》2007,123(2):317-337

The flux contribution of coherent structures to the total exchange of energy and matter is investigated in a spruce canopy of moderate density in heterogeneous, complex terrain. The study deploys two methods of analysis to estimate the coherent exchange: conditional averages in combination with wavelet analysis, and quadrant analysis. The data were obtained by high-frequency single-point measurements using sonic anemometers and gas analysers at five observation heights above and within the canopy and subcanopy, and represent a period of up to 2.5 months. The study mainly addresses the momentum transfer and exchange of sensible heat throughout the roughness sublayer, while results are provided for the exchange of carbon dioxide and water vapour above the canopy. The magnitude of the flux contribution of coherent structures largely depends on the method of analysis, and it is demonstrated that these differences are attributed to differences in the sampling strategy between the two methods. Despite the differences, relational properties such as sweep and ejection ratios and the variation of the flux contribution with height were in agreement for both methods. The sweep phase of coherent structures is the dominant process close to and within the canopy, whereas the ejections gain importance with increasing distance to the canopy. The efficiency of the coherent exchange in transporting scalars exceeds that for momentum by a factor of two. The occurrence of coherent structures results in a flux error less than 4% for the eddy-covariance method. Based on the physical processes identified from the analysis of the ejection and sweep phases along the vertical profile in the roughness sublayer, a classification scheme for the identification of exchange regimes is developed. This scheme allows one to estimate the region of the canopy participating in the exchange of energy and matter with the above-canopy air under varying environmental conditions.  相似文献