激光基准成像测量光斑图像的亚像素检测算法

在激光基准下基于CCD成像身管轴线直线度测量系统中,对激光光斑图像的高精度检测和定位是影响系统测量精度的一个重要因素.为了提高激光光斑图像的检测和定位精度,提出了一种Sobel-Guass拟合算子的激光光斑亚像素边缘检测方法,同时结合最小二乘迭代圆拟合法设计了光斑中心的高精度定位.即:首先用Sobel算子细化边缘,进而在梯度方向上进行高斯函数拟合插值,进一步提高图像边缘位置的检测精度,最后经最小二乘圆迭代拟合后得到激光光斑的亚像素级几何参数,从而使测量系统的精度提高一个数量级.实验结果表明:像素细分后对像素点的定位精度可以达到0.1个像素,亚像素边缘对标志中心的定位精度优于0.03像素.     

Panda型保偏光纤偏振轴检测技术

保偏光纤偏振轴的测定是保偏光纤应用中的关键技术。在基于图像处理的Panda型保偏光纤定轴系统中,针对应力圆边缘检测存在伪边缘造成应力圆圆心定位不准的问题,提出了一种基于最小二乘法改进的圆检测方法,通过检测到的圆参量计算阈值并剔除阈值范围外的边缘点,进行迭代拟合,迭代过程中圆参量不发生变化后停止迭代。实验结果表明:该方法可以很好地去除噪声和伪边缘对圆检测造成的干扰,并对真实Panda型保偏光纤端面图像的处理有较好的鲁棒性。     

太阳光斑质心位置检测算法的研究

为了满足对太阳光斑质心位置精确检测的要求,本文提出了一种基于迭代阈值的圆拟合太阳光斑中心检测算法。首先采用迭代阈值法计算光斑图像分割的最佳阈值,截取光斑特征点成像区域的同时有效地降低了噪声干扰,增强了算法的抗噪声性能;然后用最小二乘圆拟合中心算法精确计算光斑中心位置坐标,来提高太阳光斑质心位置检测的精度。理论分析和仿真结果表明该算法是一种实用的精确检测算法,提高了偏移检测系统的精度要求。     

印刷电路板光电图像走线检测研究

为了更精确地检测出含有噪声与模糊的印刷电路板(PCB)光电图像中走线的信息,提出了结合随机Hough变换和最小二乘法拟合直线两者优点的直线检测新方法。首先对含有走线的PCB光电图像进行预处理,给出误差阈值;然后用随机Hough变换粗略确定图像中直线的大概位置,剔除干扰点与噪声,保留符合误差阈值要求的直线附近的点集;最后用最小二乘法拟合各个集中的点,得到较精确的直线参量,从而得到各条拟合直线。对由CCD与显微镜获取PCB光电图像的走线进行实际检测,结果表明,本文提出的方法可实现精确的直线检测。     

一种基于局域亮度极大的环栅激光图像边缘检测

针对无衍射激光图像特点,提出了一种由亮环确定图像中心的方法.利用局域亮度最大原理,提取亮环屋脊边缘点;对各个亮环边缘点用最小二乘法拟合圆心,取拟合残差最小的亮环的圆心作为整幅图像中心.该方法运算速度快,对图像无需二值处理,避免了阈值选取不当对图像边缘位置的影响,可以自适应地利用周围像素亮度值来确定图像边缘.该方法已应用到船舶的同轴度检测,获得了很好的结果.     

基于转向核的单帧红外条纹非均匀性拟合校正算法

针对红外线列和非制冷型焦平面成像系统存在列向条纹非均匀性的现象,提出了一种基于转向核的单帧条纹非均匀性校正新算法。首先,根据图像边缘的梯度特性确定转向核邻域主方向和大小,然后将每列像素的转向核估计值作为该列像素的期望值,以列向条纹非均匀性作为约束进行最小二乘拟合,计算得到每列像元的校正参数,并以一定概率接受最小二乘拟合的结果。当误差函数满足事先设定阈值时,单帧图像的非均匀性校正完成。实验结果表明,该算法具有稳定的收敛性,与同类算法相比能够更有效抑制条纹非均匀性,并且能够保留更多的图像边缘信息。     

基于圆定位算法的热物理激光光斑位置定位方法

热物理激光光斑位置定位能够提高测量精度，设计一个基于圆定位算法的热物理激光光斑位置定位方法。分析激光图像的高斯分布情况，采用高斯函数描述脉冲激光，判定激光光斑空间分布形式，选择一个合适的阈值，对误差补偿，对光斑边缘检测，采用最小二乘圆的拟合准则对圆心拟合，采用圆来逼近激光光斑的轮廓，确定圆的中心点，实现基于圆定位算法的热物理激光光斑位置定位。实验结果表明，在主观分析与客观分析上，所提出的定位方法偏差都较小，能够准确获得激光光斑的中心位置，并且，在不同信噪比下，所提出的定位方法定位误差都较小，满足方法的设计需求。     

基于最小二乘支持向量机的图像边缘检测研究

本文研究了基于最小二乘支持向量机(LS-SVM)的图像边缘检测技术,利用LS-SVM对图像像素邻域的灰度值进行曲面拟合,通过采用多项式核函数、高斯核函数推导出图像的梯度和零交叉算子,并结合梯度算子和零交叉算子实现了图像边缘定位.通过实验获取了不同核函数的最佳卷积核的大小,同时采用遗传算法对不同核函数的参数进行寻优以获得最佳的边缘检测性能.通过与Canny方法的实验比较,验证了本文提出的边缘检测方法是有效的.     

光纤连接器端面检测技术的研究

采用一种显微干涉的光学检测系统,对光纤连接器的端面特性进行观测。在数据处理中,同时运用一阶导数的极值阈值方法和二阶导数过零来检测边缘点,然后采用最小二乘法进行数据拟合,来进行二维截面图的描述。从而检测端面的各种特性。     

无衍射激光光斑图像定中算法的研究

为有效识别光斑中心,针对无衍射激光斑光图像特点,提出了一种由亮度梯度确定图像中心的方法.利用光斑图像边缘的亮度梯度,设定图像二值化阈值范围,根据二值化结果确定光斑图像边缘点,对于各边缘点,利用最小二乘法拟合出圆,圆心作为光斑图像的中心.利用霍夫变换的方法去除误差点,修正圆心位置.本方法速度快、精度高,适合于实时性要求较...     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.