基于八方向卷积模板的边缘检测算法

针对传统图像边缘检测算法存在的边缘方向性不强及边缘较粗等问题,提出了一种基于八方向卷积模板的边缘检测算法。算法采用0°、22.5°、45°、67.5°、90°、112.5°、135°和157.5°八个方向的卷积模板进行边缘检测,模板权值根据中心像素点到邻域像素的距离及方向夹角的大小进行设定,充分考虑到了邻域内像素对中心点方向梯度的贡献大小,能够较好地检测出图像不同的方向边缘。对梯度图像采用了改进的非极大值抑制方法进行细化,可得到单像素的图像边缘。实验结果表明,该算法获取的边缘图像边缘较为完整,方向性强且边缘较细,整体效果明显优于传统Sobel算法。     

基于Sobel算子的改进边缘检测算法

提出了一种基于Sobel算子改进的边缘检测算法。该算法在传统Sobel算子模板基础上增加了45°方向和135°方向两个模板,提高了边缘定位的精度。在计算图像梯度时结合了方向拆分法,将每个方向梯度与两个子方向半个模板对应的像素点之和分别求比值,选择最大者作为该方向的梯度值,然后将四个方向梯度的最大值作为窗口中心点的梯度,最后对梯度图像进行阈值分割和细化,得到边缘图像。实验证明,算法获取的图像边缘与传统Sobel算法相比,具有定位准确、图像边缘较细的优点。     

基于Sobel算子的医学图像边缘检测研究

边缘检测是图像处理过程的关键技术.由于医学图像的特殊性,检测边缘的准确性对疾病的诊断和治疗有着重大的影响.针对传统Sobel算法存在定位不精确、提取边缘较粗等不足,提出了一种改进算法.算法在传统Sobel算子模板基础上增加了45°方向和135°方向两个模板,提高了边缘定位的精度,采取局部梯度均值作为阈值对初始梯度图像进行局部梯度筛选,局部弱边缘得到增强,然后对处理后梯度图像进行细化和提取,得到边缘图像.实验证明,算法获取的图像边缘与传统Sobel算法相比,具有定位准确、边连续性好和边缘较细等优点,在医学图像处理中具有一定的实用性.     

一种基于Sobel算子梯度增强的边缘检测算法

针对传统Sobel算子在图像边缘检测中存在的弱边缘提取较差及边缘较粗等不足,提出了一种局部梯度增强的检测算法.算法采用改进的Sobel算子卷积模板计算图像梯度;然后对梯度图像采用局部标准差方法增强局部弱边缘的梯度,最后对局部梯度增强的图像进行细化处理并提取图像边缘,得到边缘图像.实验结果表明,该算法获取的边缘图像边缘信息较丰富,连续性好,边缘较细,整体效果优于传统Sobel算法,具有较高的实用价值.     

基于改进Sobel算子的红外图像边缘提取算法

针对红外热像仪采集的图像边缘信息模糊,图像显示多样性,边缘信息难提取的特点,提出了一种基于Sobel算子梯度相乘的边缘提取算法.该算法首先对红外热像仪图像进行待识别目标的高温区域提取,然后分别利用增加了6个方向模板的Sobel算子和Roberts算子对图像进行边缘提取,再将得到的两幅梯度幅值图像进行梯度相乘,最终得到边缘提取图像.最后,用MATLAB对图像进行了仿真,仿真结果表明,该算法能够快速有效地提取红外热像仪图像的边缘,弥补Sobel算子的不足及提高了Sobel算子边缘检测的性能,计算简单,具有良好的检测精度,而且得到的边缘较细,极大的改善了图像边缘提取的效果.     

基于Sobel算子边缘检测的研究与改进

Sobel算子算法的优点是计算简单,速度快.但是由于只采用了2个方向的模板,只能检测水平和垂直方向的边缘,因此这种算法对于纹理较为复杂的图像,其边缘检测效果就不是很理想.采用0°,45°,90°,135°,180°,225°,270°,315° 8个方向模板对边缘进行检测,能较好地检测出不同方向的边缘.首先计算梯度,然后将梯度矩阵转化为灰度图像,使用最大类间方差法找到图片的一个合适的阈值,进行图像的二值化,得到改进后的边缘图像.     

一种简化卷积模板的抗噪型边缘检测算法

针对传统Sobel算法在边缘定位精度不高、抗噪性能差以及提取边缘较粗等不足,提出一种简化卷积模板的抗噪型边缘检测算法。算法定义了水平方向、垂直方向、45°方向和135°方向的四个简化卷积模板计算图像梯度。在计算方向梯度时,先对参与梯度计算的像素点采用阈值法进行脉冲噪声判断,将灰度值在设定阈值范围内的点视为噪声点,采用3×3窗口进行中值滤波,然后参与梯度计算,对于非噪声点,用其原值计算梯度;对获得的梯度图像进行细化处理并提取边缘图像。仿真实验表明,文中算法提取的图像边缘较细、定位精度较高,而且对脉冲噪声具有较强的抑制能力,图像整体清晰、噪声边缘较少。算法在边缘检测效果及噪声抑制能力上均优于传统的边缘检测算法及小波模变换算法。     

一种Sobel算子的抗噪型边缘检测算法

边缘检测在图像处理过程中占有重要的地位,Sobel算子是在数字图像边缘检测中常用的一种方法。经典Sobel算法简单、速度快,但也存在着边缘定位不精确、提取的边缘较粗、噪声干扰情况下抑制能力差等问题,针对这些问题,提出了一种抗噪声的Sobel边缘检测算法。算法先对图像采用多子窗口进行滤波,去除图像中存在的噪声;然后采用改进的Sobel算法对图像进行边缘检测,算法结合边缘方向计算梯度图像,并对梯度图像在3×3邻域内采用统计信息结合梯度阈值进行了2次边缘细化处理。与经典的Sobel算法及其他文献算法进行了对比试验,结果表明,该算法对噪声具有较强的抑制能力,在去除噪声的同时能够准确地检测出图像的边缘,而且得到的边缘更细,定位更精确。     

复杂光照条件下的图像边缘提取算法的改进

边缘是数字图像中的一个重要的局部特征。在复杂光照条件的情况下,图像分辨率较低,传统Sobel算子利用卷积计算出来的灰度梯度较为平缓,边缘不能有效的识别。通过改进Sobel算子的模板,平衡图像的亮边缘与暗边缘,尽可能地避免暗边缘信息的丢失。与此同时,通过分析数据建立相应的数学模型,优化子区域大小,把图像划分为多个子区域,在子区域内利用大津法进行边缘的检测与提取,最后使用Hilditch细化算法将图像的边缘提取出来。通过MATLAB仿真结果表明,与传统So bel算子的边缘提取算法相比,文中算法简单易实现,对于复杂光照条件下的图像,边缘信息提取更完整,自适应能力更强。     

基于改进Canny算子的焊缝图像边缘提取研究

针对焊缝图像边缘提取过程中,由于工件材质表面特性和复杂光照环境影响产生噪声、伪边缘干扰的问题,提出一种基于改进Canny算子的焊缝边缘提取方法。在边缘检测阶段,首先采用应用改进的双边滤波器进行滤波降噪,降低噪声的同时保留焊缝边缘梯度信息;其次应用改进的Sobel算子,增加了45°、135°方向进行梯度幅值计算,以提高边缘的定位精度。在边缘连接阶段,通过融合Otus与梯度直方图分析法自适应获取双阈值对图像焊缝进行边缘连接。实验表明,该方法在检测精度等方面优于传统Canny算法,提取的中心曲线与相对于实际焊缝中心曲线标准误差降低了46%,平均绝对偏差降低了35%,能够准确地提取焊缝边缘,同时通过自适应获取双阈值,增强了算法自适应性。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

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.