Otsu多阈值算法推广实现

遥感图像处理中的地物分割是分析和解译遥感图像的必要环节。本文分析了Otsu算法进行阈值分割的原理和有效性,针对Otsu多阈值分割算法计算效率低的缺点,提出了用Nelder-Mead单纯形法对Otsu的多阈值分割进行优化。将优化的Otsu算法与传统方法进行了比较,从理论分析和实验结果来看,此方法不仅能获得与传统方法分割一致的结果,而且应用到大尺寸遥感图像的多阈值分割中大大提高了分割效率。     

Marine ecosystem approaches to management: challenges and lessons in the United States

This study examined how the United States’ largest marine resource management agency, the National Oceanic and Atmospheric Administration (NOAA), has begun to change its management strategy away from traditional marine resource management approaches towards an Ecosystem Approach to Management (EAM). Surveys were conducted with 57 NOAA scientists and resource managers in nine NOAA programs in 8 different geographic regions across the United States in 2005. A qualitative analysis examined the attitudes and experiences of participants with respect to implementing EAM and identified four major challenges to enhancing cooperation and understanding of EAM. We conclude with recommendations for concrete initiatives that future efforts in EAM that any management agency can undertake to facilitate further ecosystem management opportunities.     

上海示范区卫星遥感海洋环境监测系统

上海示范区卫星遥感海洋环境监测系统是一套以地面卫星接收系统为基础、应用于上海示范区的海洋遥感环境监测应用系统。在发展相关遥感信息提取技术及资料同化技术的基础上，建立了完善可靠、可业务化运转的反演方法以及数值模式，提供海洋环境基本要素场的信息产品。该系统基于Windows95／98／NT平台，使用第四代软件开发语言IDL结合FORTRAN、C 开发，使用NetCDF数据存储格式。模式先进、功能强大、使用灵活、操作方便、系统稳定，是一个优秀的业务化海洋环境要素应用软件。     

Rational function optimization using genetic algorithms

In the absence of either satellite ephemeris information or camera model, rational functions are introduced by many investigators as mathematical model for image to ground coordinate system transformation. The dependency of this method on many ground control points (GCPs), numerical complexity, particularly terms selection, can be regarded as the most known disadvantages of rational functions. This paper presents a mathematical solution to overcome these problems. Genetic algorithms are used as an intelligent method for optimum rational function terms selection. The results from an experimental test carried out over a test field in Iran are presented as utilizing an IKONOS Geo image. Different numbers of GCPs are fed through a variety of genetic algorithms (GAs) with different control parameter settings. Some initial constraints are introduced to make the process stable and fast. The residual errors at independent check points proved that sub-pixel accuracies can be achieved even when only seven and five GCPs are used. GAs could select rational function terms in such a way that numerical problems are avoided without the need to normalize image and ground coordinates.     

基于广义点理论的多基线影像钣金件3D重建与尺寸检测

采用沿CAD模型在影像中投影的外轮廓边缘点统计与最邻近直线广义点平差迭代相结合的方法，实现了钣金件初始方位的2D-3D自动定位。提出利用影像上的直线信息进行广义点平差，并基于多基线影像对工业钣金件进行高精度三维重建和尺寸误差检验，给出了带端点约束条件的多基线影像广义点摄影测量平差模型，并验证了其有效性。     

A Preliminary Study on the Use of NCEP Temperature Images and Additive Tectonic Stress from Astro- Tidal- Triggering to Forecast Short-Impending Earthquakes

Taking the three earthquakes which occurred in Tibet, China during the period of July 12 to August 25, 2004 as an example,the paper analyses the M_S≥6.0 earthquakes that occurred in China and M_S≥7.0 earthquakes that occurred overseas since May of 2003 by combining the image data from the National Center for Environmental Prediction of America(NCEP)with the additive tectonic stress from astro-tidal-triggering (ATSA) and makes the following conclusions: The abnormal temperature image data of NCEP can better reflect the spatial-temporal evolution process of tectonic earthquake activity; The ATSA has an evident triggering effect on the activity of a fault when the terra stress is in critical status; using the NCEP images and the ATSA to forecast short-impending earthquake is a new concept; The three earthquakes occurred during the same phase of the respective ATSA cycle, i.e. that occurred at the time when the ATSA reached the relatively steady end of a peak, rather than at the time when the variation rate was maximal. In addition, the author discovered that the occurrence time of other earthquake cases during 2003～2004 in Tibet was also in the same phase of the above-mentioned cycles, and therefore, further study of this feature is needed with more earthquake cases in other areas over longer periods of time.     

Fractal Approach,Analysis of Images and Diagenesis in Pore Space Evaluation

Simple net model constructed by authors, facies analysis and compaction models, were applied to evaluate reservoir properties of sandstone facies of the Carpathian Flysch (the Istebna sandstones). The applied net model was built on the base of fractal approach proposed by Don Turcotte in 1977 and computer analysis of images. Laboratory measurements include porosity, density, permeability to nitrogen, mercury injection capillary pressure tests, and microscopic analysis of thin sections. D.W. Houseknecht's theory, proposed in 1987, was applied for compaction and cementation modeling. The residual saturation data were used to validate obtained results. Net model allows an evaluation of filtration properties of analyzed sandstones and to distinguish the classes of similarity of pore space. The extracted parameters of classes of similarity were correlated with facies scheme of the investigated geological structure. Influence of compaction and cementation on pore space parameters was discussed.     

利用NOAA/AVHRR监测青海省草地生产力变化的研究

青海省地处青藏高原，生态环境脆弱。近20年来，由于气候变化和人类活动的共同影响，生态环境，特别是草地资源发生了较大的变化。利用美国地球资源观测系统数据中心探路者数据库(Pathfinder Data Sets)1981-1999年间的NOAA／AVHRR NDVI资料序列，分析了青海省近20年来草地生产力变化的时间特征及地区差异性。     

Sea WiFS与AVHRR资料自动几何配准

研究了一种自动几何配准的方法,来实现多时相的卫星资料和不同遥感资料之间的几 配准。利用海岸线自动选取ＧＣＰ的点,借助相关松弛法录找同名点,且有判别机制来保证ＧＣＰ的正确性,可以方便地得到分布密集的ＧＣＰ值。同时研究了二元ｎ次方程组和ＧＣＰ数目与配维精度的关系,得到ＧＣＰ数目的增加可明显提高几何配准精度。利用该方法对ＳｅａＷｉＦＳ和ＡＶＨＲＲ资料进行了几何配准,可以提高几何配准的精度和节省机时,为遥