一种新的车牌号码倾斜校正方法

利用矩阵奇异值特征向量计算倾斜车牌图像的旋转角α,把倾斜图像旋转±(90-α),进行水平倾斜校正;在垂直倾斜校正中,论文提出了K-means聚类拟合直线法和最小二乘拟合直线法等两种校正方法,分别计算出垂直倾斜角θ,并对水平倾斜校正后的图像进行逆错切变换,得到最终的校正图像.实验结果表明,论文方法能快速准确地检测出图像的倾斜角,并具有较强的抗干扰性和应用适应性.相对于Hough变换校正方法,论文算法缩短了处理时间,在相同的条件下,处理时间比Hough变换快了4.13倍.为图像倾斜校正提供了一个新的有效方法.     

改进的Hough变换在校正汽车牌照倾斜中的应用

针对汽车牌照的自动识别中倾斜问题，对Hough变换提出了新的用法。首先，根据灰度确定汽车图像中车牌的位置和范围，取出包含车牌的子图像；然后对子图像中的点作二级Hough变换算法，计算出子图像中主要直线的角度，该角度被认为是车牌的倾斜角度；最后，用插值旋转的方法进行校正。仿真实验验证了本文算法的有效性。     

基于版面的拍照文档图像倾斜校正

文档图像版面十分复杂,建立一个较为通用的文档图像倾斜校正算法是很困难的。因此提出了基于版面的文档图像倾斜自动校正算法,并且对经典的霍夫变换检测直线的方法进行了改进,最后采用最小距离法对这些直线进行拟合,避免了因利用传统的最小二乘法拟合直线所带来的缺点。针对不同的文档版面采用相应的倾斜校正策略,实验表明该方法具有适应性强、倾斜校正速度快和精度高的特点。     

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。     

船牌识别系统中的变形校正方法研究

因摄像机角度而造成的图像倾斜和畸变,会给船牌的字符分割和识别带来不利影响.针对此问题,提出了一种新的变形校正方法.首先对定位后的船牌采用轮廓跟踪算法提取轮廓信息;然后采用一种基于Hough变换和K均值聚类直线拟合算法取得牌照的边框参数;最后通过双线性空间变换和灰度插值完成图像的校正.实验表明,这里提出的方法符合船牌图像的特点,具有较高的鲁棒性和工程实用性.     

一种用于弹道终端飞机红外图像机轴检测的算法

以制导引信一体化(GIF)为背景,利用红外成像导引头图像信息,对飞机目标姿态识别技术展开研究;在提取出飞机目标图像骨架的基础上,提出一种改进的Hough变换与最小二乘拟合相结合的算法检测出了飞机轴线。利用Hough变换鲁棒且不需启发信息的特点进行初步检测,确定直线存在的大致区域;利用最小二乘拟合法确定直线区域内特征点回归直线的精确参数;对该算法进行仿真。仿真结果表明,提出的该算法提高了飞机轴线检测的检测率和检测精度,降低了对Hough变换的分辨率要求,可以减小算法整体的空间开销。     

基于核心区域检测的手写维吾尔文本行倾斜校正方法

为了提高手写维吾尔文本图像的可读性与识别精度,对其倾斜校正显得非常重要.本文以克服传统Hough方法需要手动设置不同参数、计算量繁重等缺点为出发点,在原始启发式学习方法的基础上,确定文本行核心区域、下基线,最终完成倾斜校正,采用大津算法计算阈值,确定文本行核心区域,而后使用最小二乘拟合技术得到文本行下基线;每个倾斜角在合理间隔范围内,对图片采用旋转算法完成倾斜校正.这种技术首次运用在手写维吾尔文本行的倾斜校正中,初步得到了非常明显的实验结果.     

基于改进Hough变换的印刷电路板定位配准

电路板自动光学检测中常通过检测电路板的边缘直线来确定其旋转角度和平移量从而完成定位配准,存在运算量大、精度不高的问题.对传统Hough变换检测直线方法进行改进,从图像金字塔、约束投票角度、约束搜索点的区域3个方面提高Hough变换的效率,并利用最小二乘拟合法提高检测精度.定位配准时,先运用改进的Hough变换求取电路板边缘直线的近似参数;然后在原图上对边缘直线进行拟合求取电路板的精确旋转角度和平移量,完成定位配准.实验表明本文方法能准确完成电路板的定位配准,对大小为1 920×1 080像素的电路板图像,定位时间约为60 ms,定位误差小于1个像素.     

一类参数空间利用率最优的直线检测方法

针对Hough变换过程中参数空间利用率低的问题,提出了一类直线检测方法,该方法极大地提高了参数空间的利用率.首先提出了基于仿射变换的Hough变换的实现方法,然后提出了实现完全空间Hough变换的充分必要条件并给予证明,从而建立了能够实现完全空间Hough变换的仿射变换形式,最后提出了一种典型的完全Hough变换形式并给出了算法的详细计算过程.对图像进行特定的仿射变换以改变其定义域,对仿射变换后图像进行Hough变换并计算直线参数.仿真结果表明:该方法对参数累加数组的利用率可以达到100%;同时,与其他方法相比,检测精度得到了提高.     

基于主元分析的倾斜车牌图像校正方法研究

文章提出了一种基于主元分析（PCA）的车牌图像倾斜校正新方法。该方法将原始的像素坐标矩阵经过中心化后转换为2维协方差矩阵，再奇值分解为能反映图像倾斜方向的2维对角矩阵和坐标变换矩阵。校正算法的时间复杂度分析与实验结果均表明：相对于Hough变换等校正方法，PCA方法缩短了计算时间1-2个数量级，并且在污迹、光照不均等条件下也能获得较好效果。     

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