Luminance adaptation model for increasing the dynamic range of an imaging system based on a CCD camera

We propose a luminance adaptation model (LAM) to increase the dynamic range of an imaging system when scenes containing areas of low and high illumination are imaged. The LAM that we developed is based on capturing images at different exposure times to obtain digital levels within the linear response zone for all the pixels in the image. The levels are subsequently transformed to a reference exposure time that is common to all pixels. We use a linear transformation whose coefficients are determined by the digital levels obtained for a set of flat-spectrum samples. In this study, the LAM is applied to a multispectral imaging system that is based on a CCD camera used for color measurements and spectral reconstructions. It is shown to be a very useful method for increasing the dynamic range of the system, whilst maintaining its accuracy.     

常见饮料中咖啡因的拉曼光谱定性检测

利用激光拉曼光谱仪在微弱光信号检测方面的优点,用测试范围200nm-800nm,测试精度0．1nm的激光拉曼光谱仪对几种常见饮料进行测试,将265nm处咖啡因特征峰作为判断依据,定性检出饮料中含有咖啡因。     

Analysis of distances between inclusions in finite binary stochastic materials

A generalized probability density function (PDF) describing the distribution of inter-inclusion distances in finite, isotropic, binary stochastic materials with fixed diameter inclusions has been developed and tested. The new probability density function explicitly accounts for edge effects present in finite two- and three-dimensional stochastic materials. The generalized PDF is shown to include factors that are dependent on both the geometry of the material region as well as the statistical properties of the material. A discussion of the properties and application of this newly developed PDF is provided along with supporting numerical results for case studies in one- and two-dimensions. These numerical results demonstrate the ability of the newly derived PDF to correctly account for edge effects in finite stochastic materials, while still reproducing the expected distribution within the bulk material region.     

超声检测中变采样问题研究

本文对超声检测中常遇到的变采样问题进行讨论，比较了两种实现方法：基于特征值的二次采样和滤波器组，并给出了二次采样算法。通过试验，对这两种方法在超声信号变采样前后时频域特性的变化做了比较分析，得出前者可以很好地保留检测中所需的特征信号，但频域特性较差；而后者有很好的频域特性，便于进行时频分析。     

The mechanism for SEU simulation by pulsed laser

~~The mechanism for SEU simulation by pulsed laser~~     

Monte Carlo simulation of magnetic nanostructured thin films

Using Monte Carlo simulation, we have compared the magnetic properties between nanostructured thin films and two-dimensional crystalline solids. The dependence of nanostructured properties on the interaction between particles that constitute the nanostructured thin films is also studied. The result shows that the parameters in the interaction potential have an important effect on the properties of nanostructured thin films at the transition temperatures.     

四象限探测器用作激光准直的特性分析

以四象限光电探测器用作激光准直为例,对其探测原理、光电转换特性、影响探测精度的因素进行了理论分析。用数值模拟、实验验证了分析结果,并对影响探测精度的因素进行了深入的探讨,从而为四象限探测器用作激光准直提供了有力的理论依据。     

基于红外图像编码的运动预测相关算法

针对运动预测过程中单一匹配准则的不足提出了一种联合匹配准则,能较好地处理小目标的灰度渐变。基于运动预测过程中不断进行的像素块匹配运算提出了一种新的像素抽样算法,该算法使得运算量大大减少,匹配精度逼近全像素匹配算法。这两种技术的综合应用使得整个运动预测效率有较大改善。     

超高速发射实验模型的数值计算

 采用三阶精度PPM（Parabolic Piecewise Method）方法和VOF（Volume of Fluid）相结合,运用Lagrange-Remapping算法,编制了多介质流体高精度欧拉计算程序MFPPM,可以对多介质复杂流场进行数值计算。对程序计算精度进行了测试,并应用于超高速发射实验模型数值计算,对Sandia实验室不带会聚作用的实验模型进行了一维计算以及带会聚作用的实验模型进行二维计算并与其实验结果和CTH计算结果进行对比,其中一维计算最大相对误差1%,二维计算相对误差4.7%,在此基础上对超高速发射设计模型进行了初步计算。     

数字全息图变频采样研究

根据Whittaker-Shannon抽样定理,对菲涅耳全息图进行变频率采样,保证整个全息图各部分采样频率为该处相应空间频率的两倍,从而完全消除数字全息图由于采样冗余而带来全息图的信息冗余.并且,对变频采样后的全息图进行线性插值恢复即可获得良好的再现像质.实验和理论均证明了该方法的有效性和可行性,为全息图的信息存贮与传输提出一条新的思路.