考虑圆形特征边缘模糊和偏心误差修正的高精度相机标定方法

针对立体视觉系统采用圆形特征点标定时存在的空间圆形投影边缘模糊和偏心现象问题,利用改进Zernike矩和偏心误差修正进行圆心的高精度定位,以此提高相机参数的标定精度。首先考虑了由于立体视觉成像系统的标定场景光照强度不均匀引起的圆形特征投影图像边缘模糊的问题,引入高斯误差函数对边缘过渡段的灰度分布进行描述,建立了高斯边缘模型,并基于该模型计算投影图像的Zernike矩,然后利用改进Zernike矩实现高精度的圆形特征投影边缘像素坐标定位。此外,分析了影响圆形特征中心投影点和拟合圆心间偏差大小的因素,基于该分析对迭代拟合圆心进行偏差补偿使之逼近真实的圆心投影,最后通过所提算法对99圆形标志点进行圆心坐标提取并用于相机参数的标定。仿真实验表明,文中算法对投影图像边缘定位的精度以及圆心拟合的精度均高于传统的算法;实测实验中,基于圆心高精度坐标得到的相机标定参数对标准杆进行三维重建,长度测量精度比传统算法提高了30%。     

圆形标志点的亚像素定位及其应用

标志点定位是三维形貌测量的关键技术之一,其精度在很大程度上决定着系统的测量精度。其中,圆形标志点以其定位精度高、易于识别的优点得到了广泛的应用。结合Canny边缘检测、目标识别、亚像素边缘检测等技术,提出了一种可用于对复杂背景下的圆形标志点进行亚像素定位的方法。仿真实验证明该方法可以保证0.02像素的定位精度。随后,给出了一种利用圆形标志点进行深度像匹配的实例。     

保偏光子晶体光纤图像特征孔中心提取算法

保偏光子晶体光纤快慢轴的检测是保偏光子晶体光纤应用的关键技术。针对保偏光子晶体光纤端面空气孔数量多、尺寸存在差异及噪声和伪边缘干扰圆心定位精度的问题,提出一种双峰均值二值化法粗定位和径向扫描三点法精定位相结合的方法。采用双峰均值二值化法实现空气孔重心的粗定位;利用大空气孔定方位,选取两个具有结构对称的空气孔区域,去除粗大误差点,径向扫描法确定边缘三点进行圆心精定位,并利用半径阈值减小误差。实验结果表明,该方法能有效分割光纤端面图像,圆心偏差小于0.2个像素,为光纤定轴打下必要的理论基础。     

基于像素分解的圆形标志点亚像素定位研究

影像中圆形标志点的定位对于数字摄影测量具有重要作用.通过对圆形标志点边缘处的混合像素进行亚像素定位,提取出标志点的亚像素级边缘,再基于最小二乘原理进行椭圆拟合得到圆形标志的中心坐标.运用三种实验表明,与直接采用像素级边缘进行拟合定位相比,该方法的精度明显提高.     

图像的快速亚像素边缘检测方法

提出了一种新型的测量图像快速亚像素边缘检测方法。首先,利用标准的Sobel算子进行边缘点的粗定位,确定边缘点的像素级精度位置和边缘的方向;然后,沿边缘点的边缘方向拓展像素,得到长度为6的像素灰度值向量,将向量带人利用最小二乘曲线拟合方法得出的公式,求出边缘点的精确位置,从而能够实现亚像素边缘定位精度。实验证明：该方法的定位精度为0．1pixels,算法的运行时间为0．53s。     

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.     

一种快速准确识别圆形目标的新算法

在对二值圆形图像深入认识的基础上,研究了自动提取图像中圆形目标的理论,提出了圆的两个重要参数:圆上像素数与半径比值参数,以及理想半径与圆上像素到圆心(实际半径)差值参数.首先对图像进行降噪和边缘提取,然后利用这两个重要参数,在二值边缘图像中非常快速、有效地提取出圆形目标,并输出其半径和圆心坐标参数.实验表明,该方法能够较高精度、较快速度地在大面积图像中识别圆形目标.     

基于改进的Canny算子和Zernike矩的亚像素边缘检测方法

为满足电荷藕合器件(CCD)图像测量系统的快速、高精度测量要求,提出了一种基于改进Canny算子和Zemike矩的图像亚像素边缘检测新方法.该算法先利用改进的Canny算子进行边缘点的粗定位,在像素级上确定边缘点的坐标和梯度方向,然后再根据构造的边缘点向量和参考阈值,用Zernike矩算法对边缘点进行亚像素的重新定位,...     

一种改进的亚像素边缘检测方法

为满足测量系统的快速、高精度的图像测量要求,提出一种基于传统Zernike矩结合小波变换实现亚像素边缘检测的方法。算法先用小波模极大值原理对图像粗定位,再用Zernike矩算法对边缘进行亚像素定位,并用最大类熵阈值法计算阈值,实现图像的亚像素边缘检测。实验表明,该方法抗噪性能好,且检测精度更高,能达0.1~0.2个像素。     

基于视觉图像的石英摆片参数精密测量方法

为了解决检测石英摆片易划伤和提高检测的速度、精度,提出了利用视觉图像进行石英摆片平面几何参数测量的非接触测量方法.该方法通过视觉系统对石英摆片图像进行摄取, 由Sobel算子对图像进行单像素精度的边缘初始位置定位,进而利用改进的Zernike矩亚像素定位算法实现对目标边缘的精确定位,最后通过最小二乘法拟合边缘点得出石英摆片的平面几何参数.实验结果表明:该方法稳定性好,测量精度高,定位精度优于0.1 pixel,可实现石英摆片平面几何参数的精密测量.     

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.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.