Research for Horizontal Parallax Only Kinoform in 3D Display

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｔｈｅｈｏｌｏｇｒａｐｈｉｃｄｉｓｐｌａｙ ,ｗｉｔｈｗｈｉｃｈｔｈｅｏｂｊｅｃｔｗａｖｅｆｒｏｎｔｃａｎｂｅｒｅｃｏｒｄｅｄａｎｄｒｅｃｏｎｓｔｒｕｃｔｅｄ ,ｉｓｔｈｅｐｒｏｍｉｓｉｎｇｔｅｃｈｎｏｌｏｇｙｆｏｒ3Ｄｄｉｓｐｌａｙ .Ｇｅｎｅｒａｌｌｙ ,ｔｈｅｄｉｆｆｒａｃｔｉｏｎｅｆｆｉｃｉｅｎｃｙｏｆｈｏｌｏｇｒａｍｓｉｓｌｏｗｏｗｉｎｇｔｏｔｈｅｚｅｒｏｏｒｄｅｒａｎｄｏｔｈｅｒｈｉｇｈｅｒｏｒｄｅｒｄｉｆｆｒａｃｔｉｏｎｏｆｔｈｅｈｏｌｏｇｒａｍｓ.Ｏｎｔｈｅ…     

用二元光学技术制作反射式相息图

采且Ｇｅｒｃｈｂｅｒｇ－Ｓａｘｔｏｎ（Ｇ－Ｓ）迭代算法，在物域和频域之间进行多次迭代，使频谱的振幅大致为常数，并对频谱的位相进行量化，用二元光学技术制成了８台阶反射式相息图（ｋｉｎｏｆｏｒｍ）再现时获得清晰的像，衍射效率较高。     

Characteristics in optimization of CGH for array generator

A method of simulated annealing in optimization of a computer generated holo-gram(CGH)is presented.The characteristics of energy in annealing curve are analyzed.Thecooling schedule such as giving an initial temperature,the temperature function,the numberof interactions and stopping criterion are discussed.As an example,an optimization of phaserelief kinoform,a CGH with multiple phase levels,is implemented.     

一种三维物体相息图的迭代计算方法

在传统迭代傅里叶变换算法的基础上,提出了一种计算三维物体相息图的新方法.基于层析法将三维物体的多个分层物面作为衍射再现图像,在一个输入面(相息图)和多个输出面(再现像)之间进行迭代.通过在傅里叶迭代运算中引入距离相位因子,表示物体不同物面的深度,体现了物体的三维特征.实验结果证明了本文算法良好的收敛特性和再现性能.最后,分析了物面数量和间距对全息再现质量的影响,利用液晶空间光调制器采用时分复用的方法还原了三维物体的多个物面.     

一种新的三维计算全息图的计算方法

介绍了一种制作真实三维物体计算全息图的新方法。用摄像机记录三维物体在非相干光照明条件下两个正交方向上不同视角的一系列投影像，将这些投影像导入计算机，在MATLAB中对其作快速傅里叶变换。对这一系列二维投影像的傅里叶变换图进行抽样，得到三维物体在透镜后焦平面上的光场分布，进而制成一张计算全息图。结果证明该方法可以实现对真实物体三维全息图的合成，并且在算法实现上更加简单，提高了程序的运行速度，有利于改善全息图再现像的质量。为解决真实物体相干全息记录中光源功率和相干长度对全息记录可行性的限制指出了一个新的方向。     

Digital Holographic Particle Tracking Velocimetry for 3-D Transient Flow around an Obstacle in a Narrow Channel

Digital holographic particle tracking velocimetry (PTV) is developed by single high-speed camera and single double pulsed laser with high frequency pulses. This system can directly capture 1000 hologram fringe images for 1 second through a camera computer memory. The 3-D particle location is made of the reconstruction by using a computer hologram algorithm in a personal computer. This system can successfully be applied to instantaneous 3-D velocity measurement in the water flow with a square obstacle, and can obtain an average of 300 instantaneous velocity vectors.     

全数字全息术在图像信息隐藏中的应用

提出了全数字全息术在计算机图像信息隐藏中的应用。待隐藏的秘密信息以及公开的承载信息均为灰度级静止图像。首先对待隐藏的计算机信息图进行全息变换,即通过计算全息图的制作步骤制作出全息图的图像文件,然后再进行Arnold对称性变换。在此基础上,将秘密图像嵌入到承载图像的DCT域的中频系数中。全数字全息术的引入进一步增强了隐藏图像的透明性,通过控制制作全息图时的参数可起到加密的作用,相当于增加了一把秘密钥匙,具有较高的保密性和稳健性。     

Zone-Plate Interferometer for Measuring the Shape Error of Mirrors with Large Numerical Aperture and Steep Asphericity

A compact zone-plate interferometer is developed to measure the shape error of concave mirrors. A diffracted light of (0, 0) and that of (-1, -1) or (+1, +1) are used in the interferometer. The interferometer enables us to measure the shape error of mirrors with a large numerical aperture and a steep asphericity. The shape errors of a spherical mirror and a parabolic mirror are measured by the interferometer, and that of the former agrees well with that measured by Fizeau interferometer. Methods for adjustments of zone plates and the mirrors being tested are proposed to perform precise measurements of the mirror shapes.Presented at the International Commission for Optics Topical Meeting, Kyoto, 1994.     

用于集成成像3D显示的曲面微透镜阵列设计与仿真

针对集成成像3D显示观看视场范围小的问题和微透镜之间间隙的杂散光干扰导致的显示质量下降问题,提出了适合柔性显示及曲面显示器的曲面针孔/微透镜阵列结构.采用TracePro光学仿真软件对基于曲面针孔/微透镜阵列的集成成像3D显示的记录和重构过程进行仿真,结果显示:在记录和重构阶段,曲面针孔/微透镜阵列可以有效地减少透镜阵列之间杂散光引起的图像质量变差的问题;当记录和重构阶段均用曲面/针孔微透镜阵列时,记录三维物体的视角大,获得重构图像的视场角也相对较高.采用旋转接收屏法获取不同观看视角下的图像质量,当曲面针孔/微透镜阵列的曲面度数为30°时,重构图像质量最好.     

激光光刀法三维测量系统中的光谱匹配问题

用激光光刀法三维工业测量系统在室外进行大型堆场体积测量时，太阳幅射形成强烈的背景噪声，严重影响激光光刀图像的对比度，甚至湮没掉光刀图像。通过埘太阳光谱特性、大气吸收特性、被测物体的反射特性、光学成像系统的透过特性及CCD图像传感器的光谱响应特性的分析，提出了激光波长的选择与CCD光谱响应特性的匹配原则，并给出了相应实验结果。     

Evidence from numerical modelling for 3D spreading of [001] screw dislocations in Mg2SiO4 forsterite

Computer simulations have previously been used to derive the atomic scale properties of the cores of screw dislocations in Mg₂SiO₄ forsterite by direct calculation using parameterized potentials and via the Peierls–Nabarro model using density functional theory. We show that, for the [001] screw dislocation, the parameterized potentials reproduce key features of generalized stacking fault energies when compared to the density functional theory results, but that the predicted structure of the dislocation core differs between direct simulation and the Peierls–Nabarro model. The [001] screw dislocation is shown to exhibit a low-energy non-planar core. It is suggested that for this dislocation to move its core may need to change structure and form a high-energy planar structure similar to that derived from the Peierls–Nabarro model. This could lead to dislocation motion via an unlocking–locking mechanism and explain the common experimental observation of long straight screw dislocation segments in deformed olivine.     

超声传感器测不同浓度溶液中的声速及研究

介绍了超声传感器等的应用,得出了通过相位比较法测量在不同浓度溶液中的声速并进行研究的一种新方法。同时利用C语言编程进行数据处理,避免了烦琐的计算且误差较小,使结论更合理。