增强图像的客观质量评价算法研究

增强图像是指与原始图像相比,在清晰度、饱和度和亮度等方面所增强的图像。图像增强被广泛应用在生活中。因此,对增强图像精确的质量评价具有非常重大的意义。然而,现有的增强图像质量评价算法不能够对增强图像的质量进行精确评价。文章算法综合考虑增强图像与原始图像的结构相似度、色彩饱和度相似度和清晰度相似度对增强图像作出评价。文章算法在现有的增强图像数据库中的测试结果显示,文章算法的性能优于传统的质量评价算法和现有的增强图像质量评价算法。     

基于自适应阈值改进暗通道先验图像增强技术

基于暗通道先验的图像增强技术在图像的去雾和增强方面具有较好的图像增强效果.针对基于暗通道先验图像增强算法在处理有雾图像存在大面积白色高亮区域时出现的失真,提出了基于自适应阈值的改进暗通道先验算法.该算法在对图像进行直方图统计的基础上,先判断图像是否存在大面积白色高亮区域,并对区域的面积进行标识和统计,得到自适应系数β,再利用该系数对暗通道先验算法进行修正,最终进行对比度增强实现图像的去雾增强效果.实验结果表明,该方法能够有效消除图像去雾过程中出现的失真,提升图像质量,具有较高的实用价值.     

基于自适应阈值的改进暗通道先验图像增强技术研究

基于暗通道先验的图像增强技术在图像的去雾和增强方面具有较好的图像增强效果。针对基于暗通道先验图像增强算法在处理有雾图像存在大面积白色高亮区域时出现的失真,提出了基于自适应阈值的改进暗通道先验算法。该算法在对图像进行直方图统计的基础上,先判断图像是否存在大面积白色高亮区域,并对区域的面积进行标识和统计,得到自适应系数β,再利用该系数对暗通道先验算法进行修正,最终进行对比度增强实现图像的去雾增强效果。实验结果表明,该方法能够有效消除图像去雾过程中出现的失真,提升图像质量,具有较高的实用价值。     

基于改进的同态滤波和Retinex的水下图像增强的算法研究

光在水下传播受到微粒和水吸收作用的影响,导致水下图像对比度低,含有噪声且存在颜色偏差.针对传统的同态滤波算法增强后的图像还存在雾状模糊且颜色偏暗的问题,提出改进的同态滤波与Retinex多尺度融合的水下图像增强算法.该算法首先用基于双边滤波的单尺度Retinex算法对原始图像进行颜色校正;然后对修正后的图像构造相应的Butterworth陷波滤波器进行滤波;最后对颜色修正后的图像和同态滤波增强后的图像进行多尺度融合.通过实验可得,该方法能够有效地改善色偏,提高图像的清晰度.     

采用两阶段混合策略实现的低照度图像增强算法

在深入分析现有各主流低照度图像增强(Low Light Image Enhancement,LLIE)算法的基础上,提出了一种采用两阶段混合策略实现的低照度图像增强(Hybrid LLIE,HLLIE)算法.具体地,在第一阶段,对于给定的低照度图像,利用互补效果较好的Fu和Ying两个主流LLIE算法分别对其进行增强预处理,所得到的两张增强后图像称为初步增强图像;在第二阶段,将所得到的两张初步增强图像输入到预先训练好的多通道浅层卷积神经网络(Multi?channel Shallow Convolution Neural Network,MSCNN)模型中,由MSCNN模型将两张初步增强图像优化组合为一张具有更高图像质量的最终增强图像.实验结果表明:与各主流LLIE算法相比,所提出的HLLIE算法在各个客观图像质量评价指标上有显著优势,人工主观评价亦能证实这一点.     

面向图像集的置信区间内一致性增强质量评价准则

在对整个图像集进行增强质量评价时,现有的平均准则会随着不同图像集非一致性地变化,从而导致较大的评价质量波动。为此,该文提出一个面向图像集的置信区间内一致性增强质量评价准则,通过设置应用参数并使用置信区间筛选数据,再比较各图像增强前后的质量分数差值,由此评估图像质量增强的一致性,最终计算出一致性增强质量分数有效值。在众多图像增强算法中,所提准则能够挑选出具体应用所需要的稳定性强、可靠性高的增强算法。实验结果表明,所提准则具有良好的主客观评价一致性,性能优于当前的平均准则,为各种图像增强算法提供了一个可用于任意图像集的质量评价准则。     

基于矿山井下视频监控系统的图像增强方法研究

针对煤矿井下照度低、粉尘多的恶劣环境导致矿山井下图像质量差、图像可分辨率低的问题,提出一种基于脊波变换的图像增强算法,采用多种评价标准对增强后的图像进行评价,并且与直方图均衡化算法、小波增强算法进行比较。结果显示,该算法能够更好地增强图像的边缘、对比度和细节信息,图像效果从整体上更加符合人眼视觉标准。     

采用深度学习与图像融合混合实现策略的低照度图像增强算法

提出了一种采用深度学习与图像融合混合实现策略的低照度图像增强算法.首先,利用照射分量预测模型直接基于输入的低照度图像快速地估计出其最佳照射分量并在Retinex模型框架下获得一张整体上适度曝光图像;其次,将低照度图像本身及它的过曝光图像作为适度曝光图像的修正补充图像参与融合;最后,采用局部结构化融合和色度加权融合机制技术将制备好的3张待融合图像进行融合以获得最终的增强图像.实验数据表明:本文算法相较于各种主流对比算法在主客观图像质量评价指标上均有显著优势,在局部图像结构细节上具有更好的边缘保持和颜色保真效果.     

基于改进直方图均衡化和SSR算法的灰度图像增强研究

为了提高偏亮和偏暗图像的增强效果,提出了一种改进的直方图均衡化和SSR算法相结合的灰度图像增强方法.对原始图像进行改进直方图均衡化增强,提取低频分量进行直方图均衡化,与高频分量融合;对原始图像进行SSR算法增强;将得到的2个图像进行加权融合.结果表明:新方法得到的图像比原始图像细节特征突出,视觉效果明显改善;对比度和信息熵得到提高、亮度得到调整.在医学X射线图像上验证了其可行性,与其他增强算法相比,新方法更有利于图像的准确分析.     

基于分数阶Retinex的低照度图像增强方法

低照度彩色图像增强在生活中起着重要作用,传统的低照度彩色图像增强算法往往会引起图像的不同程度失真。为了增强低照度彩色图像而又不引起图像失真,本文提出了一种新的低照度图像自适应对比度增强算法。将分数阶微积分、传统Retinex变分法与分段对数变换饱和度增强法相结合,构造一种新的分数阶Retinex图像增强算法。实验结果表明,该方法具有增强图像对比度的同时又能保持边缘和纹理细节的能力。与传统低照度图像增强算法相比,能突出图像的细节纹理信息,同时图像色度和亮度也有明显改善。     

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