基于图像中值灰度相似度函数加权曲率滤波算法

曲率滤波算法通过构造滤波算子快速优化变分模型,但全变分曲率滤波及高斯曲率滤波易致去噪过平滑且椒盐噪声去除较差.提出了基于图像中值灰度相似度函数加权曲率滤波算法,其中,中值灰度相似度函数方差取决于小波变换最高频子带系数,能较好防止图像过平滑,且提高椒盐噪声去除能力;因此,采用中值灰度相似度函数分别对局部高斯曲率与局部全变分曲率投影算子加权,并分别迭代局部加权高斯曲率投影算子与局部加权全变分曲率投影算子,直至输出图像梯度总能量满足停止条件.实验表明,基于图像中值灰度相似度函数加权全变分曲率滤波与加权高斯曲率滤波比传统全变分曲率滤波和高斯曲率滤波去噪效果更好.     

基于灰色关联度的图像混合噪声的自适应滤波算法

利用中值滤波和灰色关联度的特点,提出基于中值滤波和灰色关联度相结合的混合噪声图像滤波算法.算法选取加窗混合噪声图像的中值,采用灰色关联度自适应地计算各像素的加权系数,通过加权得到结果.实验结果表明,该算法有较好的自适应性,不但能够有效去除含有高斯噪声和脉冲噪声的图像噪声,而且能较好地保护图像的细节信息,提高图像的去噪效果和清晰度.     

直方图加权均值滤波器

本文提出了一种适合于消除图像盐椒噪声的滤波器——直方图加权均值(HWM)滤波器.该算法以加权均值滤波器为基础,利用被污染图像的直方图函数作为权值进行加权运算.实验表明,对于噪声率在5％到90％的的噪声图像,HWM滤波器具有良好而稳健的去噪效果,当噪声率超过70％时,其优越性更加突出.     

基于CMOS图像传感器混合噪声的自适应滤波算法

针对中值滤波导致部分图像细节损失和均值滤波出现模糊现象,设计了一种适用于椒盐和高斯混合噪声的自适应滤波算法.该算法先用最小邻域的均值和阈值判断噪声类型,然后使用加权中值滤波处理椒盐噪声,再利用拉普拉斯算子和相应阈值判断图像边缘细节,最后对高斯噪声进行加权均值滤波.实验仿真结果表明,从图像视觉效果来看,相比单独使用中值和均值滤波降噪,自适应滤波算法对图像的还原效果更好,图像细节保存较好,模糊程度相对较弱,图像更清晰.通过对比峰值信噪比(PSNR)和均方误差(MSE),对混合噪声进行处理时,滤波算法的PSNR和MSE值优于中值和均值滤波,有效还原了噪声图像.整个算法是在最小邻域空间进行,易于实现,对混合噪声的处理效果较好,为图像处理的系统集成化设计提供了技术支持.     

一种群稀疏限制的消除条带噪声变分模型

在对图像变分描述的前提下,为有效地利用条带噪声之间的相似性,本文将条带噪声的群稀疏表示引入到单向变分模型中,提出群稀疏技术限制的单向变分模型,并采用交替方向乘子法求解该模型。对比实验证明,本文所提出的群稀疏限制的单向变分模型能有效地利用条带噪声的相似性实现条带噪声的消除,更好地重构图像的细节信息,峰值信噪比与结构相似性比其他模型分别提高6.76dB和0.25,图像去噪性能更优。     

应用变分法的极化SAR图像分类方法研究

提出了一种用于图像分类的变分模型,该模型结合正则化过程,可以较好地保持图像边缘信息,同时可以用于图像恢复.利用模拟和真实SAR图像的分类仿真试验表明,基于变分法的极化SAR图像分类方法不仅能够实现SAR图像的正确分类,克服SAR图像中相干斑噪声的影响,并且算法快速,易于实现.     

基于相关度量的高椒盐噪声软阈值直方图滤波算法

利用图像邻域相关和直方图对椒盐噪声的鲁棒性,提出了一种针对高椒盐噪声图像的软阈值直方图加权滤波算法.对邻域灰度相关进行了量化分析,定义了灰度相关函数作为信号邻域相关性的度量,并将该系数作为直方图加权滤波算法的软阈值,根据像素被判定为噪声或有效信号的概率,自行调整滤波强度,减少图像滤波处理中的细节损失.仿真结果表明,对于高椒盐噪声图像,本算法在椒盐噪声滤除方面有良好的表现.     

一种基于曲率变分正则化的小波变换图像去噪方法

噪声和图像的细节特征主要集中于图像高频部分,在图像去噪过程中,图像的某些重要特征（如边缘、细小纹理等）易受到破坏.针对这一情况,本文提出基于曲率变分正则化的小波变换图像去噪方法,首先用小波提取图像的高频成分,对图像进行增强处理,然后用增强图像的水平集曲率建立一个基于水平集曲率的曲率驱动函数,再将曲率驱动函数作为一个校正因子引入到变分模型中,建立曲率变分模型,用以控制图像的整体结构.在缺乏图像梯度信息的情况下,该模型克服了ROF模型错误扩散这一缺点,符合图像处理的形态学原则.最后,用建立的曲率变分模型处理提取的高频成分,重构处理后的高频成分和原来的低频成分,得到去噪后的图像.分析和仿真结果表明,新算法可有效抑制噪声,有极高的图像结构相似度,去噪效果明显.     

欧拉弹性正则化的图像泊松去噪

利用泊松噪声分布与图像灰度值相关这一特性,结合图像的水平集曲线对图像灰度值的刻画能力,在Bayesian-MAP框架下,提出了欧拉弹性正则与泊松似然保真的图像泊松去噪变分正则化模型.利用交替方向乘子法,将原问题转化为几个不同低阶子问题的求解.对于子问题中出现的高阶非线性项,利用滞后扩散不动点迭代进行线性化,从而得到模型的快速迭代求解算法.通过数值模拟实验,证明了当图像受不同强度泊松噪声影响时,所提出的泊松去噪方法都能够有效的抑制泊松噪声,同时具有良好的结构保持性能.     

一种基于灰色关联的去椒盐噪声滤波算法

利用灰色关联理论结合开关滤波策略的思想,提出了一种基于灰色关联的去椒盐噪声算法。算法采用开关策略,对于噪声点,选取3×3滤波窗口内的非噪声像素,利用灰色关联度计算各像素的加权值,将各非噪声像素加权后替换噪声点像素值,得到滤波图像。仿真实验证实,该算法不仅有效抑制了图像中的椒盐噪声,而且较好地保持了图像的边缘细节,滤波效果明显优于传统的滤波算法。     

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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