鱼眼图像畸变的双向经度快速校正方法

大视场角的鱼眼镜头在成像时由于不同视场垂轴放大率不同,从而产生畸变使最终成像弯曲变形,这为识别和测量等应用带来了不便。针对传统经度校正方法的不足,将算法改进为双向经度鱼眼图像快速校正算法。通过对鱼眼图像有效区域进行划分,并对不同区域内的畸变点在横、纵两个方向上分别建立校正模型,确定畸变图像与理想图像之间坐标映射关系,求取校正坐标的位置。最后对图像进行非线性拉伸,改善图像中心与边缘放大率不同而产生的"膨胀感",获得符合人眼视觉习惯的图像。运用Matlab对3组图像进行校正实验,结果表明,该算法能快速有效地对鱼眼图像进行畸变校正。     

基于网格图像自动检测的镜头畸变校正*

针对广角镜头所采集图像存在的畸变问题,提出了一种基于模板匹配和质心检测的高精度控制点检测法,并采用基于除法模型和正交相干相位检测法对畸变网格图像进行了高精度校正。实验结果表明,该镜头畸变校正算法能克服光照等不定因素,对畸变的网格图像交叉控制点进行高精度自动提取,并自动计算畸变图像中每一点的校正参数,实现了镜头畸变的高精度、全自动校正。     

一种实用的CCD像机标定方法

机器视觉测量系统中,对于短焦距、视场角较大的CCD镜头,图像畸变较大,为了获得高精度的测量结果,需要对镜头进行标定.提出了一种实用的像机标定方法,采用了从畸变像点到理想像点变换的镜头畸变模型,通过优化搜索算法,得到了镜头畸变参数.进行了CCD像机标定实验,实验结果表明,该方法得到的摄像机的内部参数和镜头畸变参数能较好地还原畸变图像.     

基于精确模型和逆投影的超大视场红外图像畸变校正

针对超大视场红外图像畸变大、与人眼视觉差异明显的问题,提出了一种基于精确模型和逆投影的超大视场红外图像畸变校正算法以改善其视觉效果.该算法首先利用精确模型对超大视场红外相机成像中的物、像关系进行描述;然后,针对红外图像像素采样率不高的缺点,利用较为精确的三次卷积插值法对图像进行插值来补全成像信息;最后,根据校正图像上的待赋值像点的坐标,结合校正模型和超大视场红外相机精确模型,计算该像点逆投影到插值图像时的对应坐标,并以最近邻像点像素值作为校正后图像像点的赋值.车载道路场景下的超大视场红外图像畸变校正实验结果显示,所提出的算法图像校正结果边界清晰、无锯齿效应,对场景中的直线平均还原偏差小于0.35 pixels,表明该算法对超大视场红外图像畸变校正具有较好的适用性.     

基于光学系统畸变设计曲线的畸变校正方法

为消除短焦光学系统的畸变给测量精度带来的不利影响,提出了基于光学系统畸变设计值和全视场拟合畸变参数曲线的方法对畸变进行标定和修正,通过测量视场内若干点的像元角分辨率并拟合其与视场角的关系,给出一条抛物线形式的畸变参数曲线,并将其用于测量.相对于传统的分区域最小二乘拟合参数校正的方法,其实现过程更简单,精度更高.实验结果表明在焦距50 mm和125 mm时,在仅使用一半标定数据的情况下可比分区域校正方法提高精度约22％.     

F-Theta光学镜头的畸变标定及测角精度分析

对于精密测角定位系统来说,畸变的存在会直接 影响测量的几何精度,因此需要对光学系统进行畸变标定以 便于后期的畸变校正。为了解决F-Theta光学镜头的畸变标定 问题,建立了一种基于精密测角法的标定系统,并详细论述了畸变标定过 程。通过实验测得了视场与绝对畸变量之间的关系。利用基于曲线拟合的最小 二乘逼近方法求解出了F-Theta光学镜头的焦距。最后对F-Theta光 学镜头的测角精度进行了分析。结果表明,该镜头满足秒级测角精度的要求。     

基于球面坐标定位法校正鱼眼图像

鱼眼镜头摄像机具有大视场角的特点,常用于视觉监控、虚拟实景技术以及机器人导航等许多计算机视觉领域的应用中。鱼眼图像的变形给后期的图像处理带来麻烦,所以在后期处理中首先需要解决鱼眼影像的畸变问题,所以必须进行校正。本文根据球面坐标定位法,从鱼眼镜头的成像原理,鱼眼图像有效区域的提取,及鱼眼中心和半径的确定,详细地介绍了鱼眼图像的校正过程。     

用于交通监控系统的光学成像镜头的设计

设计一种用于交通监控系统的宽波段大孔径光学成像镜头,利用红外光的大气窗口,可在黑暗中或能见度不佳的环境中得到清晰的图像。为了对近红外光与可见光成像,采用CCD作为图像传感器,选用的CCD像元尺寸为4.65μm,其分辨率极限为110lp/mm。镜头的F数为1.6,视场角为16.8°,中心波长为880nm的近红外光,工作波段为400～1000nm。通过计算光学镜头的参数,选用松纳型作为镜头初始结构,通过软件优化,在110lp/mm空间频率处所有视场的调制传递函数(MTF)值超过0.3,最大畸变小于0.1%。     

利用Hough变换实现自动镜头畸变校正

在摄像机拍摄到的图像中,图像难免会出现某种程度的畸变,给生活带来了很多不便。Hough变换算法是一种应用非常广泛的图像检测方法,但其缺点为计算容量大,运算速度慢等,因此提出了一种新的算法,利用高阶Hough变换通过自动曲线校正来找到用来校正的可靠的曲线和准确估计镜头的畸变参数。实验结果表明,该算法可行而且还能够将广角镜头,鱼眼镜头和变焦镜头的摄像机拍摄到的畸变图像进行自动校正。     

鱼眼镜头图像畸变的校正方法

提出了一种校正鱼眼镜头图像畸变的新方法。通过追迹光学系统的主光线,获得它在投影平面上的径向位置与它在像平面上位置之间的关系曲线;然后用傅立叶级数拟合该关系曲线;并求出该级数的逆函数,结果就可以根据畸变图像复原没有畸变的图像。用该方法数值模拟两个鱼眼镜头系统的图像畸变校正;并用其中一个鱼眼镜头（尼康16 mm/F2.8）拍摄的两张图像进行了畸变校正实验。结果表明,当设置投影平面和物平面重合时,恢复的图像相对于物体的残余径向高度误差非常小（小于0.25%）。实验证明了该方法是可行的。     

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.     

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.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

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正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its