Reflection and Refraction on Implicit Surfaces

Implicit surfaces are often used in computer graphics. They can be easily modeled and rendered, and many objects are composed of them in our daily life. In this paper, based on the concept of virtual objects, a novel method of real-time rendering is presented for reflection and refraction on implicit surface. The method is used to construct virtual objects from real objects quickly, and then render the virtual objects as if they were real objects except for one more step of merging their images with the real objects＇ images. Characteristics of implicit surfaces are used to compute virtual objects effectively and quickly. GPUs （Graphics Processing Units） are used to compute virtual vertices quickly and further accelerate the computing and rendering processes. As a result, realistic effects of reflections and refractions on implicit surfaces are rendered in real time.     

Atmospheric refraction corrections of radiowave propagation for airborne and satellite-borne radars

The atmospheric refraction corrections of radiowave propagation for airborne and satellite-borne radars for the spherically stratified (horizontally homogeneous) atmosphere (including lower atmosphere and ionosphere) are discussed. First, the critical apparent depression angle for radar and the perigee of ray are found using the refractive index profile close to the lowest point of the ray as the refractive index profile of spherically stratified atmosphere, and strict expressions of line-of-sight distance for radar that take account of refraction are presented. Then, to which condition the atmospheric refraction to be corrected belongs is determined, and the positioning corrections for all the twelve atmospheric refractive conditions are made using ray-tracing method. At last, the velocity-measuring corrections are made.     

用激光束研究地表大气层的竖直折光

介绍作者试用激光束研究地表大气层竖直折光的方法及分析实验成果得出的主要结论 :折光差概略模型 ,湍流随机误差和周日折光差的特性 ,气温与折光变化的时间延迟 ,近似逆转时刻的时间分布等。由于常规地面测量都是在这一层内进行的 ,因此本文对于精密高程测量特别是精密三角高程测量以及用此法进行的高塔柱和超长遂道的施工放样测量等都具有参考价值。     

复杂山区的静校正方法探讨

静校正问题是复杂山地地震资料处理的关键。本文针对柴达木盆地复杂山地资料,分析了静校正问题的特征,总结了在复杂山区静校正问题中所采用的几种方法（包括多域交互迭代静校正方法、广义线性反演法、地表一致性的剩余静校正法、非地表一致性的剩余静校法）。 这些方法都有其适用性和局限性,只有“因地制宜”地采用这些方法,才能见到好的效果。     

对射线传输系统的推广及应用

基于高频射线理论,并通过Fermat原理以一致的形式讨论了左、右手媒质界面上电波或光波的折射特性．在所得折射定律的基础上结合引入相位的辛空间坐标,对矩阵光学进行了推广．相应传输理论的表示仍然保持了Gauss理论的辛几何本质,从而可以适用于左、右手媒质混合的系统．     

折射型X射线组合透镜研制进展

折射型X射线聚焦组合透镜(XCRLs)是一种利用折射效应对X射线聚焦成像的新型光学元件.本文从制作材料和结构设计两方面,系统介绍了目前X射线折射聚焦组合透镜在国内外的发展状况及其主要的应用领域.     

用分光计测液体折射率

根据分光计测定棱镜折射率的实验方法,提出了可以用分光计测定透明液体的折射率。从理论上推倒出最小偏向角及此时入射角、折射角满足的条件,并且得出光线通过平板玻璃时不会发生折射、只会平移的结论,由此结论可用平板玻璃构成一个内部充满待测液体的棱镜。最后通过实验论证了此方法的可行性。     

三维折射波静校正

在地表复杂的工区进行三维地震勘探,静交正是资料处理中的一个重要环节。本文提出了用折射波初至时间计算静校正量的新方法,即分别在共炮点域,共接收点域,共偏移距域交互计算静校正量。     

激光对空中目标测距的大气修正研究

根据大气结构特性提出了一个只需测量站大气参数的激光大气距离修正公式 ,它对大气层内、外目标具有普遍的适应性 ,而且能适应于低仰角目标的修正 ,其距离修正计算误差 ,在仰角大于 5°时 ,优于 2 .5cm。     

风廓线雷达测量精度分析

风廓线雷达是用于大气风场探测的无线电遥感系统,实践表明它是一种很有发展前途的测风设备。本文介绍了我所边界层风廓线雷达的组成和工作过程,分析了边界层风廓线雷达的测量精度。