多地质目标地表控制照明叠前深度偏移

控制照明偏移是面向地质目标的快速偏移技术，它可通过控制目的层处震源波场的方向特性，改善目标区域的成像质量。本文提出的多目标地表控制照明方法，旨在针对介质的复杂情况，适当选取多个目的层，同时对多个目标区域进行地表控制照明，从而获得多个目标区域构造的更精细成像。文中对Marmousi模型进行了多目标地表控制照明偏移数值计算，并与单目标地表控制照明、常规炮域及平面波偏移等方法进行了比较，结果表明多地质目标照明叠前深度偏移不仅能够显著提高多个目标区域的成像质量，而且对于常规炮域偏移也具有较高的计算效率。     

激光空间相干性对照明均匀性影响的实验研究

对激光束空间相干性对照明均匀性的影响进行了实验研究。实验结果表明,激光束的空间相干性与照明均匀性具有密切的关系,当激光束空间相干性降低时,目标上照明光斑的闪烁率和功率谱密度也下降,激光照明的均匀性得到提高。所得结果对实际工作中照明激光器的选择是有用的。     

变系数线性模型参数的递推估计

变系数线性模型参数的递推估计胡峰（西安卫星测控中心７１００４３）关键词递推估计，最小二乘法，变系数线性模型１引言在工程数据的综合处理中，特别是在卫星及运载工具的动态目标跟踪与精密定位时自从Ｂｒｏｗｎ［‘’提出最佳弹道自校准估计（ＥＭＢＥＴ）技术以来，...     

基于序贯蒙特卡罗滤波的MIMO快时变信道跟踪

高数据传输速率以及终端的高速移动,导致无线通信信道具有时间选择性与频率选择性两个特征.本文主要研究了基于训练序列的多输入多输出（MIMO）时变频率选择性衰落信道的估计与跟踪问题.首先,根据时变无线信道的动态性,将信道冲击响应近似看作一个低阶的自回归矢量过程（AR）,以便于进行时变信道的跟踪.接着在此模型的基础上,利用序贯蒙特卡罗滤波对MIMO通信系统中的双选择性信道进行了跟踪;跟踪过程中需要与信号检测交替进行,即在状态变量的预测和新息修正的中间要进行一次码元的检测,所采用的方法是极大似然序列检测,最后与扩展卡尔曼滤波作了比较.仿真结果表明,在信道噪声是非高斯的情形下,序贯蒙特卡罗滤波的跟踪性能更优越于扩展卡尔曼滤波.     

浅谈红外系统防激光致盲问题

叙述了激光辐照对红外系统的致盲作用，介绍了红外系统对抗激光致盲的几种方法。     

建筑的日照能被控制吗？：关于“阳光管道”的设想

提出了对建筑物日照进行人工控制的新设想，阐述了“阳光管道”的概念和工作原理，以期引起人们的兴起和注意，进行深入的研究。     

A multi-illuminant synthetic image test set

A new multi-illuminant synthetic image test set called MIST is described and made publicly available. MIST is intended primarily for evaluating illumination estimation and color constancy methods, but additional data are provided to make it useful for other computer vision applications as well. MIST addresses the problem found in most existing real-image datasets, which is that the groundtruth illumination is only measured at a very limited number of locations, despite the fact that illumination tends to vary significantly in almost all scenes. In contrast, MIST provides for each pixel: (a) the percent surface spectral reflectance, (b) the spectrum of the incident illumination, (c) the separate specular and diffuse components of the reflected light, and (d) the depth (ie, camera-to-surface distance). The dataset contains 900 stereo pairs, each of the 1800 images being a 30-band multispectral image covering the visible spectrum from 400 to 695 nm at a 5 nm interval. Standard sRGB versions of the multispectral images are also provided. The images are synthesized by extending the Blender Cycles ray-tracing renderer. The rendering is done in a way that ensures the images are not only photorealistic, but physically accurate as well.     

综合考虑多种变形因素的近岸多向不规则波传播数学模型-I.模型的建立

根据线性波动的叠加原理和波浪方向谱理论,作者在综合考虑环境水流(水流因子)、非线性弥散影响(非线性因子)、底摩擦波能损失(底摩擦因子)、非缓坡地形影响(地形因子)、折射、绕射的近岸规则波传播基本方程的基础上,推导出了综合考虑多种变形因素的近岸多向不规则波传播变形的基本方程。使用有限差分作为数值方法,给出了波浪破碎和障碍物后边界的处理方法,建立了综合考虑环境水流(水流因子)、非线性弥散影响(非线性因子)、底摩擦波能损失(底摩擦因子)、非缓坡地形影响(地形因子)、折射、绕射、波浪破碎、障碍物影响的近岸多向不规则波传播变形数学模型。该模型以组成波的谱值及波向为变量,在实数域内求解,适合大面积海区波场计算。     

Shape and View Independent Reflectance Map from Multiple Views

We consider the problem of estimating the 3D shape and reflectance properties of an object made of a single material from a set of calibrated views. To model the reflectance, we propose to use the View Independent Reflectance Map (VIRM), which is a representation of the joint effect of the diffuse+specular Bidirectional Reflectance Distribution Function (BRDF) and the environment illumination. The object shape is parameterized using a triangular mesh. We pose the estimation problem as minimizing the cost of matching input images, and the images synthesized using the shape and VIRM estimates. We show that by enforcing a constant value of VIRM as a global constraint, we can minimize the cost function by iterating between the VIRM and shape estimation. Experimental results on both synthetic and real objects show that our algorithm can recover both the 3D shape and the diffuse/specular reflectance information. Our algorithm does not require the light sources to be known or calibrated. The estimated VIRM can be used to predict the appearances of objects with the same material from novel viewpoints and under transformed illumination. The support of National Science Foundation under grant ECS 02-25523 is gratefully acknowledged. Tianli Yu was supported in part by a Beckman Institute Graduate Fellowship.     

基于信息熵的蒙特卡罗全局光照的自适应抽样

在真实感图形生成领域里，蒙特卡罗方法是计算整体光照问题的极佳选择。但是，在用基于蒙特卡罗的全局光照算法生成的图像中，当没有足够多的采样量的时候，存在大量的噪声。自适应抽样方法是减少这种噪声的一种很好的方法。该文提出了一种新的基于信息熵的自适应抽样算法。实验结果表明，该方法的效果优于香农信息熵等经典方法。