基于成像几何模型的火星探测器定位研究

对数亿千米之外的火星探测器进行跟踪导航定位,是火星探测的关键技术之一.目前,我国深空网尚未建成,利用中国VLBI网对火星探测器“火星快车”的定位精度仅约0.1as,难以为火星探测器的精密定轨提供数据保障.提出以遥感影像进行火星探测器几何定位的全新技术方法,利用严密传感器成像几何模型,通过地面控制点在物方空间坐标系中的坐...     

TDI CCD相机动态成像对几何质量的影响研究

本文通过影像模拟的方法分析动态积分成像对空间TDI CCD相机成像几何质量的影响。首先对卫星固有推扫速度、像移速度与电荷转移速度失配、卫星三轴姿态运动及偏流角误差等4种动态成像因素进行了介绍,建立了4种因素的数学模型;在此基础上提出了空间TDI CCD相机成像模拟方法;最后提出统计单级静态影像和多级动态合成影像配准误差的分布特点评价与4种因素有关的内部几何质量,统计低阶多项式拟合的姿态曲线与实际姿态曲线条件下地面点像方误差的分布特点评价外部几何质量。     

基于ARX的扫描地形图的自动纠正

提出了顾及扫描分辨率和格网点分布的自动识别格网点方法,利用CAD提供的ISMAPI函数库,采用VC 编程,对扫描的地图影像实现像素级自动纠正,提高了纠正精度和自动化程度,并可适应影像非均匀变形的情况.     

Comparison of geoelectrical imaging and tunnel documentation at the Hallandsås Tunnel, Sweden

For construction in rock a thorough pre-investigation is important in order to avoid unforeseen conditions which may delay the work. It is crucial to remember the results from this investigation in the further work, and use the experience from the construction to update the geological prognosis and reduce the uncertainties. Different geophysical methods have proved valuable tools in such investigations. In this work the electrical imaging is evaluated with regards to the method's applicability. The evaluation is done qualitatively by comparing the electrical imaging with tunnel documentation from a tunnel in Southern Sweden. By evaluating the result continuously when making the tunnel a more detailed geological prognosis can be compiled and used in the continued work with the tunnel. The parameters used for the comparison are lithology, Q, RQD, weathering and water leakage. The result was that virtually every change in electrical resistivity image coincides with a change in rock conditions. The general trend was that high resistivity corresponded with good quality gneiss whereas low resistivity corresponds to poor quality rock e.g., high weathering, low RQD, low Q and/or several lithological contacts. The intermediate resistivity is often amphibolites or rock with water bearing fractures. The results were supported by in-situ resistivity measurements inside the tunnel and resistivity logging in a core drilling. Geoelectrical imaging proved to give valuable information for a detailed geological model, which could be compiled for a section where the tunnel had not yet been drilled as a help for planning of the continued tunnel work. As is the case other geophysical methods it is clear that for the interpretation of data a priori information about the geological setting is necessary.     

偏移速度分析与偏移成像

偏移速度分析和偏移成像是地震资料处理的两个重要组成部分.目前时间偏移技术比较成熟,而深度偏移技术也在逐步完善,时间域偏移成像主要推崇叠前时间偏移法.采用沿层叠加速度分析技术可获得层面上准确的叠加速度,并通过倾角校正、叠前时间偏移和CRP反偏移速度分析逐步优化速度,得到一个符合地质规律、准确的均方根速度场;通过深度偏移方法的研究,总结了建立精确偏移速度场的方法,并提出了一种地震资料处理的思路,即基于射线追踪的Kirchhoff偏移和基于波场延拓的波动方程偏移的结合,使偏移速度分析和偏移成像在应用效果和效率上得到了很大的提高.     

Seismic Reflection Characteristics of Naturally-Induced Subsidence Affecting Transportation

High-resolution seismic reflections have been used effectively to investigate sinkholes formed from the dissolution of a bedded salt unit found throughout most of Central Kansas. Surface subsidence can have devastating effects on transportation structures. Roads, rails, bridges, and pipeliues can even be dramatically affected by minor ground instability. Areas susceptible to surface subsidence can put public safety at risk. Subsurface expressions significantly larger than surface depressions are consistently observed on seismic images recorded over sinkholes in Kansas. Until subsidence reaches the ground surface, failure appears to be controlled by compressional forces evidenced by faults with reverse orientation. Once a surface depression forms or dissolution of the salt slows or stops, subsidence structures are consistent with a tensional stress environment with prevalent normal faults. Detecting areas of rapid subsidence potential, prior to surface failure, is the ultimate goal of any geotechnical survey where the ground surface is susceptible to settling. Seismic reflection images have helped correlate active subsidence to dormant paleofeatures, project horizontal growth of active sinkholes based on subsurface structures, and appraise the risk of catastrophic failure.     

EH-4电磁成像系统在隐伏构造探测中的应用

EH-4电磁成像系统具有勘探深度大、反映成果直观、轻便高效等优点.本文介绍了EH-4电磁成像系统的基本原理、数据采集和数据处理方法,及其在云南西部探测构造深部延伸情况的应用.实践证明,EH-4技术在探测构造深部延伸的应用方面是有效的.     

基于LA-ICP-MS多元素成像技术的早寒武世磷结核成因研究

我国下寒武统底部广泛发育磷结核、磷块岩等富磷沉积,为早寒武世最为重要的化学标志层之一,也代表了隐生宙—显生宙转折期地球表层系统的重大变革。当前对磷来源和富集机制的解释不一。为进一步明确该时期富磷沉积的形成机制,本文利用激光剥蚀电感耦合等离子体质谱联用技术(LA-ICP-MS)对贵州金沙地区牛蹄塘组黑色页岩中的磷结核进行多元素原位微区成像研究。结果表明:磷结核中各元素富集情况清晰地记录了磷结核形成过程中微环境的变化趋势。其中,磷结核内部Ca、P共富集以及Si亏损,指示P富集缘于自生磷灰石生成,P则来自于有机质含氧或厌氧降解释放;Mn、Zn与P共富集于磷结核内部,指示结核形成时的底部水体为含氧水体;As、Mo、V等元素主要富集于围岩或黑色页岩,指示缺氧含H_2S水体形成终止了结核生长。本研究显示,LA-ICP-MS原位多元素成像技术能够获取微区内丰富的地球化学信息,并提供高精度可视化证据,未来将在地质勘探和古环境研究等领域得到更广泛应用。     

X-ray computed tomography of planetary materials: A primer and review of recent studies

X-ray computed tomography (XCT) is a powerful 3D imaging technique that has been used to investigate meteorites, mission-returned samples, and other planetary materials of all scales from dust particles to large rocks. With this technique, a 3D volume representing the X-ray attenuation (which is sensitive to composition and density) of the materials within an object is produced, allowing various components and textures to be observed and quantified. As with any analytical technique, a thorough understanding of the underlying physical principles, system components, and data acquisition parameters provides a strong foundation for the optimal acquisition and interpretation of the data. Here we present a technical overview of the physics of XCT, describe the major components of a typical laboratory-based XCT instrument, and provide a guide for how to optimize data collection for planetary materials using such systems. We also discuss data processing, visualization and analysis, including a discussion of common data artifacts and how to minimize them. We review a variety of recent studies in which XCT has been used to study extraterrestrial materials and/or to address fundamental problems in planetary science. We conclude with a short discussion of anticipated future directions of XCT technology and application.     

高分辨率光学遥感卫星宽幅成像技术发展浅析

幅宽是影响高分辨率光学遥感卫星应用的重要指标。本文分析了国际上高分辨率光学遥感卫星宽幅成像的主要途径,介绍了多CCD内视场拼接、多相机外视场拼接、敏捷成像、多星组网等主流宽幅成像方式及其数据处理的技术特点,同时分析了相机垂轨摆扫成像、大面阵相机敏捷拼幅成像等新型星载宽幅影像获取方式,有助于系统地了解高分辨率光学遥感卫星宽幅成像技术进展,对于展望其发展趋势具有一定的参考作用。