未知DEM下的机载SAR图像几何校正方法研究

针对机载环境复杂,不确定因素众多,与图像相对应的DEM不能精确获得等影响校正的不利因素,研究基于先验条件而不依赖DEM的机载SAR图像几何校正方法.从产生畸变的原理和校正过程的本质出发,将不同的几何校正理论在成像原理层面进行统一;在此基础上,分析精确校正所需要的条件,并提出当条件不能满足时的基于统计模型的几何校正方法;继而提出基于不同先验条件的校正方案决策模型.仿真实验及基于配准区域的保真度评价结果验证了所提方法的有效性.     

京津冀都市圈热环境空间格局遥感分析

以京津冀都市圈热环境为研究对象,利用MODIS数据获取了2001、2004、2006和2008年的地表温度,通过温度距平图定性分析京津冀都市圈不同时间、不同城市的热岛强度及变化规律;利用景观学知识,参考热力景观空间格局评价体系,选取缀块个数(NP)、蔓延度指数(CONTAG)和香农多样性指数(SHDI)等对北京、天津两市的热环境空间格局进行了定量描述.结果表明,2001～2004年间北京热力景观格局趋于分散(除夏季外),2004年后逐渐呈集聚状态;夏季北京的热力景观格局异于其它季节,2004年的最为集聚,而2008年的较往年破碎,热场极分散;天津市热力景观格局变化趋势不太明显.     

柴达木盆地烃蚀变矿物高光谱遥感识别研究

高光谱遥感识别烃蚀变矿物可用于探测油气烃类微渗漏和定位地下油气藏.以有天然气分布的柴达木盆地东部三湖地区为研究区,对Hyperion高光谱数据进行重采样处理,克服了目标识别矿物不明显和传感器低信噪比的影响.通过确定烃蚀变矿物高光谱遥感探测的指示标志,采用线性光谱(SAM)拟合与光谱匹配(SAM)相结合的方法确定了影像端元对应的矿物组分.识别结果表明,合理缩减影像波段数和确定影像端元的方法,能有效提高烃蚀变矿物的高光谱遥感识别精度.     

基于线段的基本线/线拓扑关系计算

空间拓扑关系是空间数据建模、空间查询、分析、推理、制图综合、数据质量控制、数据更新等的基础。目前空间拓扑关系研究的主要成果仍然集中在拓扑关系的描述方面,在计算方面的阐述都非常薄弱,不足以指导系统开发人员编程实现。本文研究了IR2中两个简单线目标间拓扑关系的计算方法,重点分析了线/线拓扑关系计算的特点,提出了一种基于线段的线/线拓扑关系计算方法,并用VC＋＋采用底层开发模式实现了基本线/线拓扑关系的计算。     

数字高程模型生成中的高程序同构

通过揭示三维地面严密的高程有序性,揭示并定义了数字高程模型(DEM)生成中的高程序同构特性.在此基础上论证了DEM的高程序同构的必需条件--内插生成过程中与地面的拓扑对应和变换的"高处仍高,低处仍低"的数量特性,并据此论证了在DEM生成中三种主要内插方法的高程序同构特性.     

主元分析变换空间上的鉴别共同矢量人脸识别方法

给出了在主元分析(PCA)变换空间上求取DCV投影矩阵的方法(PCA+DCV),在保留所有鉴别信息的条件下,显著降低了算法复杂度,提高了运算效率.进一步提出了依据主元成分对应特征值进行适度权重的DCV识别方法(WPCA+DCV),一定程度上减小因光照、饰物遮挡等造成的面部变化带来的识别影响,增强表征信息,提高识别率.在ORL、YALE和AR人脸库上的实验结果证实了本方法的性能.     

遥感影像仿射不变特征匹配的自动优化

针对基于仿射不变特征的遥感影像匹配技术,提出了一种自动优化方法,以进一步提高匹配准确性.根据典型需求形成了两套优化实施方案,基于所提出的自动优化方法实现了相应具体算法.针对不同类型的多组影像,自动优化的效果与相应方案的预定目标一致,充分证明了本方法的有效性与适用性.     

冲绳海槽岩浆物理化学性质及其地质意义

借助冲绳海槽火山岩地球化学分析结果,讨论了海槽不同区段岩浆的温度、压力、密度和黏度等物理化学参数,以确定海槽岩浆的物理性质及其对海槽不同区段岩浆演化过程的影响.海槽北段的岩浆相对于中段表现出高压力、低温度的特征.由于海槽岩浆挥发分含量较高,北段岩浆的密度和黏度要高于中段的.但总的来说,海槽岩浆具有低密度、低黏度的特点,因此岩浆更容易穿透岩石圈,而且有利于岩浆结晶分异作用的进行.对海槽岩浆相对运移速度的研究显示,在外部条件及含水量相同的前提下,在海槽中段岩浆上升速度要大于北段的,这从岩浆物理化学性质的角度解释了为何海槽中段火山活动要强于北段的.     

Low-temperature alteration of oceanic island basalts and their contribution to transition metal circulation of the ocean

The major elements, rare earth elements （REE） and trace elements of four basalt samples from central and western Pacific ferro- manganese crust provinces have been analyzed using chemical methods and ICP - MS, respectively. The results indicate that the samples have been extensively altered and that the contents of their major elements have changed significantly. However, the similarity of REE partition patterns and trace element contents of basalt samples to those of fresh oceanic island basalts （OIB） indicate that the basalt samples originated as OIB. Because of low-temperature alteration, the contents of A1203 , Fe203 , MnO, K20 and P205 increased, while MgO and FeO decreased. Active components, such as magnesium and iron, were leached from OIB resulting in the relative enrichment of SiO2. The leaching of active components can cause the relative enrichment of REE, while the precipitation of LREE-rich ferromanganese oxides in vesicles and fissures not only causes an increase of REE contents, but also induces ＂fractionation＂ of LREE and HREE. Based on the enrichment mechanism of REE contents, the theoretical quantities of precipitated ferromanganese oxides and the depleted quantities of active components are calculated ： the depleted quantities of active components for the unit mass of fresh basalts vary in the range of 0.15 ～ 0. 657, and the precipitated quantities of ferromanganese oxides for the unit mass of fresh basahs vary in the range of 0. 006 ～ 0. 042. Of the major elements, the two most depleted are iron, and magnesium, with 18.28% ～ 70.95% of iron and 44.50% ～ 93.94% of magnesium in the fresh basalts was leached out. Theoretical calculation and geochemistry results both indicate that low-temperature alteration of basalts can supply abundant amount of metals to seawater, and may play an important role in ocean metal circulation.     

Molecular identification of scallop planktonic larvae using species-specific microsatellites

The identification of scallop larvae is essential to understand the population structure and community dynamics and to assess the potential environmental impacts caused by scallop larvae released or escaped. However, the larvae identification by morphological characteristics is notoriously difficult, mainly due to the small size （usually being less than 150 μm） and vague morphological characteristics among different scallop species. A simple and accurate molecular method was developed to identify four economically farmed scallop species, the Zhikong scallop Chlamys farreri, the noble scallop C. nobilis, the bay scallop Argopecten irradians and the Yesso scallop Mizuhopecten yessoensis. The tests used the high degree of species-specific microsatellite markers, which was specified by transferability analyses, assessed by reference individuals and evaluated by BLAST searches. The sensitivity test indicated that the species-specific microsatellites were sensitive enough for the detection of 1% -2% larvae in mixed plankton samples. Larvae collected from scallop hatcheries and their effluents and from the artificially controlled crosses were well identified to the species/hybrid level. The results demonstrated that the one-step PCR-based assay was technically simple, inexpensive and robust in identification analyses, and also less sensitive to initial quality of template DNA extracted from the ethanol-preserved samples for several years.