Electronic Absorption Spectra and Third-Order Nonlinear Optical Property of Dinaphtho[2,3-b:2’,3’-d]Thiophene-5,7,12,13- Tetraone (DNTTRA) and Its Phenyldiazenyl Derivatives: DFT Calculations

Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of Dinaphtho[2,3-b:2’,3’-d]thiophene-5,7,12,13-tetraone (DNTTRA) and its 36 derivatives containing azobenzene were calculated by using density functional theory B3LYP and M06-2X methods at 6-311++g(d, p) level, respectively. Besides, the atomic charges of natural bond orbitals (NBO) were analyzed. The frontier orbitals and electron absorption spectra of A-G5 molecule were calculated by TD-DFT (TD-B3LYP/6-311++g(d, p) and TD-M06-2X/6-311++g(d, p)). The NLO properties were calculated by effective finite field FF method and self-compiled program. The results show that 36 molecules of these six series are D-π-A-π-D structures. The third-order NLO coefficients γ (second-order hyperpolarizability) of the D series molecules are the largest among the six series, reaching 107 atomic units (10-33 esu) of order of magnitude, showing good third-order NLO properties. Last, the third-order NLO properties of the azobenzene ring can be improved by introducing strong electron donor groups (e.g. -N(CH3)2 or -NHCH3) in the azobenzene ring, so that the third-order NLO materials with good performance can be obtained.

Automated Phase-measuring Profilometry of 3-D Diffuse Objects Using a Single Phase Step Method

The technique of phase measuring profilometry using a single phase step method is proposed.This method can automatically obtain phase value at each pixel by using a discret cosine transform algorithm.The method is able to automatically recognize any position between depression and elevation on an object surface.Theoretical analysis and experimental verification are presented.

A"messenger zone hypothesis"based on the visual three-dimensional spatial distribution of motoneurons innervating deep limb muscles

Coordinated contraction of skeletal muscles relies on selective connections between the muscles and multiple classes of the spinal motoneuro ns.Howeve r,current research on the spatial location of the spinal motoneurons innervating differe nt muscles is limited.In this study,we investigated the spatial distribution and relative position of different motoneurons that control the deep muscles of the mouse hindlimbs,which were innervated by the obturator nerve,femoral nerve,inferior gluteal nerve,deep pe roneal nerve,and tibial nerve.Locations were visualized by combining a multiplex retrograde tracking technique compatible with three-dimensional imaging of solvent-cleared o rgans(3DISCO)and 3-D imaging technology based on lightsheet fluorescence microscopy(LSFM).Additionally,we propose the hypothesis that"messenger zones"exist as interlaced areas between the motoneuron pools that dominate the synergistic or antagonist muscle groups.We hypothesize that these interlaced neurons may participate in muscle coordination as messenger neurons.Analysis revealed the precise mutual positional relationships among the many motoneurons that innervate different deep muscles of the mouse.Not only do these findings update and supplement our knowledge regarding the overall spatial layout of spinal motoneurons that control mouse limb muscles,but they also provide insights into the mechanisms through which muscle activity is coordinated and the architecture of motor circuits.

CyberOptics在2008年上海Nepcon展览会上展示SE 300 Ultra^TM 3-D焊膏检测系统

CyberOptics公司宣布，在中国上海2008年4月8．11日举行的NEPCON China／EMT China2008展览会上，它将在西Ll厅第1A26号展台展示其业内领先的3．D焊膏检测系统SE 300 Ultra。

Importance of 3-D image reconstruction of spectraldomain OCT on outcome of grid laser photocoagulation for diffuse diabetic macular edema

AIM:To present the outcome of modified grid laser photocoagulation(GLP)in diffuse diabetic macular edema(DDME)in eyes without extrafoveal and/or vitreofoveal traction.METHODS:Inclusion criteria for the retrospective study were DDME eyes of patients with typeⅡdiabetes mellitus that had≥4 months of follow-up following GLP.Only one eye per patient was analyzed.Using 3-D spectral-domain optical coherence tomography(3-D SDOCT),eyes that had either extrafoveal or vitreofoveal traction,or had been previously treated by an intravitreal medication(s)were excluded.Treated DDME eyes were divided into 4 groups:A)"Classic"DDME that involved the central macula;B)edema did not involve the macular center;C)eyes associated with central epiretinal membrane(ERM);D)DDME that was associated with macular capillary dropout≥2 disc-diameter(DD).RESULTS:GLP outcome in 35 DDME eyes after 4-24(mean,13.1±6.9)months was as follows:Group A)18eyes with"classic"DDME.Following one or 2(mean,1.2)GLP treatments,best-corrected visual acuity(BCVA)improved by 1-2 Snellen lines in 44.4%(8/18)of eyes,and worsened by 1 line in 11.1%(2/18).Central macular thickness(CMT)improved by 7%-49%(mean,26.6%)in77.8%(14/18)of eyes.Causes of CMT worsening(n=4)were commonly explainable,predominantly(n=3)associated with emergence of extrafoveal traction,5-9months post-GLP.Group B)GLP(s)in DDME that did not involve the macular center(n=6)resulted in improved BCVA by 1-2 lines in 2 eyes.However,the central macula became involved in the edema process after the GLP in 3(50%)eyes,associated with an emergence of extrafoveal traction in one of these eyes 4months following the GLP.Group C)GLP failed in all 5eyes associated with central ERM.Group D)GLP was of partial benefit in 2 of 6 treated eyes with macular capillary dropout≥2DD.CONCLUSION:Eyes with DDME that involved the macular center were found to achieve favourable outcomes after GLP(s)during mid-term follow-up,unless complicated pre-GLP or post-GLP by vltreoretinal interface abnormalities,often extrafoveal traction or ERM,or by capillary dropout≥2DD.Prospective studies with larger cohorts are required.

Linear Phase FIR Filter on Measuring 3-D Surface

An optical technology for 3-D surface measurement is set up.The technology,based on a deformed projected grating pattern which carries the 3-D information of the measured object,can automatically and accurately obtain the phase map of a measured object by using a linear-phase FIR filter.In contrast to the 2-D fast Fourier transform technique,it’s more than fast.Only one image pattern is sufficient for measuring.The phase map can be processed without assigning fringe orders and making distinction between a depression and an elevation.Theoretical analysis and experimental result are presented.

条纹投影动态3维测量中相位高精度估计

为了提高条纹投影动态3-D形貌测量精度,采用加窗傅里叶分析辅助相移的方法来减小运动导致的相移误差。首先采用加窗傅里叶分析法估计变形条纹间的实际相移量,然后采用最小二乘法估计出变形条纹的高精度相位分布,最后由估计的相位计算得到场景3维形貌。理论分析了物体运动对相移量的影响,通过仿真研究了所提方法的相移量估计精度,并搭建了实验系统进行验证。结果表明,实验中采用所提方法的相位恢复精度达到0.1673rad,比现有方法有明显提高。该方法用来提高条纹投影动态3-D形貌测量中相位精度是有效的。

Profilometry with Grating Projection Based on One-step Phase Shift

An optical technique for 3 D shape measurement is presented. This technique, based on a deformed projected grating pattern which carries 3 D information of the measured object, can automatically and accurately obtain the phase map of a measured object by using one step phase shift algorithm.In comparison with traditional phase shift technique, the technique is much faster, with the equivalent accuracy. Only one frame image is sufficient for measuring. Experimental result of typical object is presented.

动态过程中破裂表面的三维重建

在冲击、爆轰等动态过程的研究中,被测三维表面将发生破裂及碎片飞散等过程,为动态过程的三维重建带来困难。针对此问题提出了一种动态过程中破裂表面的三维重建方法,这种方法以傅里叶变换轮廓术为基础,利用条纹图中裂缝的信息,生成一个三维二元控制模板,在该模板的控制下进行三维相位展开。以玻璃破裂过程的三维重建实验为例,处理结果证实了该方法的可行性。该方法可用于材料变形、爆轰过程、碰撞变形等相关领域的动态过程研究,对于深入分析冲击与爆轰过程、材料变形与破坏机理、碎片飞散规律等具有重要意义。

激光片光三维传感中提高深度分辨率的方法

提出了两种在激光片光三维传感中降低散斑噪声、提高深度分辨率的方法。第 1种方法采用宏观上相同、微观上受物体微结构面元影响的多帧散斑图像叠加 ,用于三维测量系统的标定。第 2种方法利用动态采集方式 ,使CCD对微结构元进行时间积分 ,可有效地降低散斑噪声的影响。实验证明 ,综合利用这两种方式 。

基于点阵编码的三维主动视觉标定

提出一种基于位错点阵编码三维成像系统的标定方法.首先在物空间建立三维数据基准,然后通过基准传递的概念标定摄像子系统,再通过建立摄像子系统坐标系与投影子系统坐标系之间的约束关系,将标定后的摄像子系统的准确度传递到投影子系统坐标系.摄像子系统坐标系与投影子系统都具有标定的准确度之后,可以根据位错点阵编码三维成像技术的解码算法获得深度图像空间坐标的计算值,然后将其与物体空间的三维标定数据基准进行比较,建立目标函数为误差平方和最小的非线性优化方程.通过迭代求解这个优化方程,最终获得三维系统的结构参量.实验结果表明,经过三维标定的位错点阵编码三维成像系统,对300×300×80 mm3的测量体积内,可以获得X方向的标准差为0.29 mm和Y方向的标准差为0.24 mm,Z方向的标准差为0.29 mm的测量准确度.

双摄像机傅里叶变换轮廓术的数据融合

在三维面形拼接应用当中,对拼接区域内面形数据以一定的权重进行加权平均是最常用的方法,通常的算法是以拼接边界到中心线的距离为权重,这样可以对拼接区域内各点实现平滑过渡,但在拼接区域的边界存在一定的局限性。本文将一种正弦函数形式的图像镶嵌算法引入到三维面形测量的数据融合中,很好地实现了整个拼接区域的平滑过渡。该方法运算量小,简单、快速实现数据的平滑过渡,计算机模拟实验表明,该方法是有效可行的。

2维载频条纹傅里叶变换轮廓术

为了在3维形貌测量中解决非连续物体所存在的非连续相位解包问题并提高测量精度,提出采用2维网格光栅作为空间载频条纹的傅里叶变换轮廓术。首先应用2维傅里叶变换对2维光栅条纹图像进行频谱分析;然后设计带通滤波器分离出两个1维变形光栅条纹,在1幅变形网格光栅条纹得到两个1维光栅各自所对应的包裹相位分布;最后应用查表法进行解包得到确定的调制相位分布,给出了详细的理论推导和实验结果。结果表明,采用2维网格光栅+查表相位解包法很好地解决了1维单一频率光栅条纹的低测量精度、1维双频光栅的频率混叠以及3维测量中高度不连续所存在相位解包问题,该方法是可行的。

以MATLAB为服务器的图形显示技术在三维轮廓测量中的应用

为满足光学三维轮廓测量中数据处理、图形重建与显示的需要 ,提出了一种新的方法 ,即以MATLAB作为后台运行的服务器 ,客户应用程序通过自动控制其启动和关闭并与之进行动态数据交换 ,可以很方便地利用MATLAB强大的功能进行数据处理及图形重建与显示。在介绍三维轮廓测量的基本原理、对象自动控制的概念以及MATLAB对象的外部编程接口后 ,还给出了VisualBasic和Vi sualC +

基于傅里叶变换轮廓术方法的复杂物体三维面形测量

提出一种在数字加权滤波和调制度分析基础上形成可靠性控制模板，并按可靠度排序进行位相展开的新方法。该法用于傅里叶变换轮廓术中，可以兼顾所求位相精度和位相展开的可靠度，适合复杂物体面形的测量。给出了傅里叶变换轮廓术对复杂物体面形测量的应用实例。

基于调制度测量的三维轮廓术

介绍了基于调制度测量的三维轮廓术的测量方法的原理和过程， 并给出了实物测量。结果证明它在原理上是正确的、可行的。此方法对三维轮廓术、三维传感及机器视觉的应用具有重要意义。

调制度测量轮廓术在复杂面形测量中的应用

调制度测量轮廓术(MMP)是将物体的高度信息编码在投影到待测物面上的正弦条纹的调制度信息中,可以实现对物体的垂直测量,特别适合测量表面有高度剧烈变化或不连续区域的物体。探讨了基于傅里叶变换的调制度测量轮廓术在复杂面形测量中的应用,提出了调制度焦深的概念并详细分析了调制度焦深对测量的影响,以调制度焦深为基础从测量系统设计的角度提出了提高测量精度的具体措施,给出了实验系统设计方案,讨论了影响测量精度的几个实际问题及解决方案。对复杂面形和深孔物体的实测结果表明,基于傅里叶变换的调制度测量轮廓术测量复杂面形物体可以达到较高的测量精度。

基于图像拼接和双频投影栅线法的三维形貌测量

为解决采用光栅投影式三维轮廓术测量物体三维形貌时,出现的条纹图样的不连续性,利用计算机编程,生成由两种不同频率合成的复合光栅,将它投影到被测物体上,并将被测物体放在精密的旋转平台上,通过二次成像后对两幅图像进行图像拼接,得到清晰的被光栅调制的物体图像,再对图像进行傅里叶变换,然后采用滤波器滤出相应的高频和低频成分,利用低频光栅的相位差辅助解出高频光栅的真实相位差,从而实现物体的三维形貌重建。结果表明,本方法简单、精度高,可以成功解决有突变面形和投影时具有阴影的物体的三维形貌测量问题。

双摄像机相位测量轮廓术系统标定与数据融合

在将两个摄像机对同一坐标系(全局坐标系)标定的基础上,提出了距离数据及纹理的融合方法。以调制度为模板确定摄像机视线重叠区和数据空洞,在全局坐标中摄像机视线重叠区内根据单位面积采样点数序号最接近原则选取一定尺寸的区域作为数据拼接区。并且考虑在重叠区内一方数据有空洞时的补洞方法,将空洞边界相似放大后,新边界和原边界构成的重叠区域作为数据拼接区。在数据拼接区内将两边的数据以到拼接区中心线距离为权重进行加权平均,实现了数据平滑过渡。实验表明该方法是有效的,为数据融合提供了新途径。

一种改进的单帧变形条纹在线三维测量方法

分析了单帧相位测量轮廓术(PMP,phase measuring profilometry)中影响测量精度的因素,提出了基于改进的Stoilov等步算法的在线三维测量方法,从而避免了CCD采图过程中由于抽样、量化以及取整造成的条纹周期部分缺失对满周期等相移算法的影响。较等相移满周期算法,Stoilov等步算法具有只需相移步长相等、相移步数与相移量乘积无需2π整数倍的优点,降低了对子图相移量的要求,提高了基于单帧图像的条纹投影轮廓术用于在线检测的精度。计算机模拟和实验均验证了本文方法较等相移满周期算法精度提高了3～5倍。