基于渐进式特征推理的裂缝图像修复方法研究北大核心CSCD

图像修复是计算机图形学与计算机视觉中的研究热点之一。针对传统裂缝图像修复采用一次性补全修复方法并没有语义理解能力,当语义场景较为复杂且图像缺陷较大时修复效果不佳的问题,提出了一种基于渐进式特征推理的裂缝图像修复方法。该方法从孔洞边缘逐步修复图像,加强对孔洞中心的约束。首先通过计算掩膜占比确定修复比例,使用部分卷积更新掩膜,然后利用VGG-16网络进行特征提取,再使用语义注意力机制,生成高质量的图像特征,并采用跳跃连接方法,增强遥远距离的梯度相关性,为后续图像修复提供多尺度多层次的特征信息。最后,将递归生成的特征图进行融合解码生成修复图像。实验结果表明,与传统图像修复方法相比,本方法修复的裂缝图像峰值信噪比提升了0.5 dB—1.2 dB,产生语义明确的修复结果。     

基于边缘先验的人脸去手势遮挡修复方法研究

针对当下人脸去手势遮挡任务中常出现的结构缺失和纹理模糊等问题,文章提出一种基于边缘条件和注意力机制的两阶段修复网络——EmmNet。第一阶段网络为第二阶段细节修复提供边缘指导信息,以避免出现过度平滑等问题。第二阶段网络中的并行多扩张卷积模块可在有效扩大网络感受野的同时提高对有效像素的利用率。此外,注意力模块可促使网络生成具有全局一致性,使研究者获得符合原图特征的修复图像。实验结果表明,EmmNet在去手势遮挡任务中可以生成轮廓结构更加完整流畅,细节纹理更加清晰自然的人脸图像。     

多尺度CNN与高频信息融合的图像去雾算法

针对现有去雾算法在恢复图像边缘区域效果不佳以及存在薄雾残留等问题,本文提出了一种基于多尺度卷积神经网络(CNN)与高频信息融合的图像去雾算法(HF-MSNet),采用拉普拉斯算子分离高频信息作为额外先验,用于提高图像细节恢复。首先,采用多尺度CNN作为主干网络,提取图像的主要纹理特征;其次,采用高频特征融合分支对高频信息逐阶段地提炼,并融合了通道注意力模块,使用注意力机制对不重要的特征进行约束;最后,采用高频注意力模块对全局特征自适应地筛选,整合高频特征和纹理特征的分布,得到目标的无雾图像。实验结果表明,本文的算法可以生成更自然真实的去雾图像,并在峰值信噪比(PSNR)、结构相似度(SSIM)两种指标上都达到了理想的效果。     

基于人脸结构信息引导的人脸图像修复网络

针对人脸图像修复的深度学习网络存在修复后的人脸图像面部语义信息不合理和面部轮廓不协调的问题，提出了一种基于人脸结构信息引导的人脸图像修复网络。首先，采用编码器-解码器网络技术构建人脸结构草图生成网络，并在结构草图生成网络的生成器中加入跳跃连接和引入带膨胀卷积的残差块以生成待修复区域的结构草图。其次，在构建人脸修复网络时，在修复网络生成器中引入注意力机制，让修复网络在修复过程中更多关注待修复区域，并以生成的人脸结构草图为引导从而实现人脸图像面部语义结构和纹理信息的生动修复。最后，在结构草图生成网络的损失函数中引入特征匹配损失进行模型训练，从而约束生成器生成与真实结构草图更相似的结果；在修复网络的损失函数中联合感知损失和风格损失进行模型训练，从而更好地重建待修复区域的人脸图像面部轮廓结构和颜色纹理，使修复后的图像更接近真实图像。对比实验结果表明，在人脸图像数据集中，本文所设计的网络模型的修复性能有较高的提升。     

基于推理注意力机制的二阶段网络图像修复

现有的图像修复方法在处理大面积缺失或高度纹理化的图像时,通常会产生扭曲的结构或与周围区域不一致的模糊纹理,无法重建合理的图像结构。为此,提出了一种基于推理注意力机制的二阶段网络图像修复方法。首先通过边缘生成网络生成合理的幻觉边缘信息,然后在图像补全网络完成图像的重建工作。为了进一步生成视觉效果更逼真的图像,提高图像修复的精确度,在图像补全网络采用推理注意力机制,有效控制了生成特征的不一致性,从而生成更有效的信息。所提方法在多个数据集上进行了实验验证,结果表明该图像修复方法的结构相似性指数达到了88.9%,峰值信噪比达到了25.56 dB,与现有的图像修复方法相比,该方法具有更高的图像修复精确度,生成的图像更逼真。     

基于扩散模型的人脸图像修复技术

人脸作为人体信息最为密集的部位,人脸图像在各个研究领域都有不可替代的作用。因此,研究如何将遮挡或模糊的人脸图像恢复成真实图像是非常有意义的。针对人脸图像修复技术的研究,提出基于扩散模型的人脸图像修复技术。在现有的人脸图像修复技术基础上,解决在修复大区域破损或遮挡的情况下,修复图像出现纹理模糊及结构扭曲等问题。所提出的方法基于边缘引导的扩散模型图像修复网络,主要包括两个阶段：首先训练基于U-Net结构的边缘修复模型生成较为真实的缺失区域的边缘信息,然后根据已修复好的边缘信息,训练内容生成模型填充缺失部分的内容信息。实验证明对于人脸图像修复具有较好的效果。     

一种生成对抗网络用于图像修复的方法

近年来基于深度学习的图像修复方法相比于传统方法,表现出明显优势,前者能更好的生成视觉上合理的图像结构和纹理.但现有的标准卷积神经网络方法,通常会造成颜色差异过大和图像纹理缺失与失真的问题.本文提出了一种新型图像修复深度网络模型,该模型由两个相互独立的生成对抗式网络模块组成.其中,图像修复网络模块旨在解决图像缺失区域的修复问题,其生成器基于部分卷积网络;图像优化网络模块旨在解决修复后图像存在局部色差的问题,其生成器基于深度残差网络.通过两个网络模块的协同作用,图像的视觉效果与图像质量得到提高.与其他先进方法进行定性和定量比较的实验结果表明,本文提出的方法在图像修复质量上表现更好.     

多视绘制中的空洞填充算法

绘制新视点的质量决定3D视频在显示终端的效果,为填充基于深度图像的绘制(DIBR)算法中产生的空洞,本文提出"双路纹理+双路深度"的多视绘制算法。首先,应用DIBR技术,通过左侧参考纹理图像和其对应的深度图像绘制虚拟视点图像,从经中值滤波后的虚拟图像绘制空洞掩膜图像;然后,将掩膜图像中的大空洞点坐标反变换到右侧参考纹理图像中对应的具体像素坐标,根据深度值判断得到的像素点是否属于背景区域,以此得到虚拟视点图像的空洞填充图像;最后,将空洞填充图像与左视经过DIBR得到的虚拟图像进行融合,填补大空洞,应用插值算法填充小的空洞。实验结果表明,本文方法可有效修复DIBR绘制过程中产生的空洞,得到质量较好的虚拟视点图像。     

基于模板的图像修复算法优先权的改进

研究了基于块填充的图像修复算法,修复图像的质量容易受到待修复区域边界像素修复顺序的影响,通过分析待修复区域像素点所在模块的图像特征,改进了填充算法的优先权,分别是基于P_Laplace算子和Euler' s elastics模型的优先权计算方法的改进.实验结果证实了文中所介绍算法能有效提高重建图像的感知质量.     

图像修复技术综述

图像修复技术是利用破损图像中未缺失区域信息,按照一定的修复规则,对图像中被污染或缺失的区域进行像素修补、填充.文章从目前常见的图像修复技术入手,分析比较传统的图像修复技术和基于深度学习的图像修复技术,结果认为基于深度学习的图像修复技术修复的图像在颜色和纹理等方面效果更好.     

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.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

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.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

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.     

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.