基于权重最小二乘结构边缘保持色调映射算法

高动态范围图像由于其动态范围超过普通显示器的动态范围,所以无法正常显示,从而需要研究在保留高动态范围图像对比度、细节信息以及色彩信息的情况下压缩高动态范围图像的动态范围以适应低动态范围显示器进行显示的色调映射算法。本文提出基于权重最小二乘结构的边缘保持图像平滑色调映射算法。首先,建立基于权重最小二乘的边缘保持图像平滑滤波算子;然后,将输入的高动态范围图像转换至NTSC空间分离亮度信息和颜色信息,利用该滤波算子对亮度信息进行多级分层,获得基本层以及多级细节层信息;最后,对基本层进行动态范围压缩,利用压缩后的基本层结合多级细节层信息并转换回RGB空间获得输出的低动态范围图像。文中通过实验采集的多曝光图像序列利用Debevec和Malik提出高动态范围图像融合算法获得拍摄场景的高动态范围图像,采用本文提出算法对高动态范围图像进行色调映射处理获得较为理想的保留图像有效信息的低动态范围图像,从而验证了文中提出算法的有效性。     

基于主成分分析和引导滤波的色调映射算法

针对传统高动态范围(HDR)图像色调映射算法普遍 存在色偏和效率低的问题,提出了一种基于主成分 分析(PCA)进行色彩空间转换和具有边缘保持特性的引导滤波图像增强的色调映射算法。首 先利用图像的平均亮 度实现图像Gamma自适应校正;然后采用PCA方法将图像的3个颜色分量转换为相 互正交的亮度 分量和色差分量,模拟相机响应函数(CRF)曲线压缩亮度分量的动态范围,并将结果与加权 后的色差分量联合, 经PCA逆转换得到新的RGB分量;最后利用引导滤波方法对图像进行增强,提高 图像对比度,避 免光晕现象。实验结果表明,本文算法效率比经典的iCAM06算法提高了4倍以 上,并能有效避免偏色和 光晕现象,处理后图像的细节清晰层次感强、色彩自然丰富,不仅能用于传统的便携式显示 设备,而且可用于穿戴式智能视觉辅助设备和无屏幕显示器等新兴领域。     

基于颜色空间转换的高动态图像双屏显示方法

针对高动态范围图像映射后偏色问题及图像细节显示不足问题,提出了一种基于颜色空间转换与双屏结合的显示方法。首先将高动态图像转换到HSL空间,采用自适应对数算法进行亮度映射及相应的饱和度增强,再次转换到RGB空间并进行LCD-FED双屏分割显示。实验结果表明该方法不仅解决了偏色问题,而且在细节表现能力上也有了很大的提升,其失真度仅为3.7%。     

多参数亮度值重映射的颜色传递方法

为了提高灰度图像中人眼视觉的情景感知和目标的识别率,提出了多参数亮度值重映射的颜色传递方法,将灰度图像赋予色彩。该方法首先将灰度目标图像和彩色参考图像由RGB颜色空间转换到亮度与色彩分离的YCbCr颜色空间。然后,引入由彩色参考图像和灰度目标图像的列数和亮度共同决定的参数,对彩色参考图像的亮度值进行运算,使彩色参考图像与灰度目标图像具有相同的亮度值动态范围。最后,根据目标像素和它周围的像素存在相关性,进行灰度目标图像与彩色参考图像的像素匹配后,将得到的结果再逆变至可以表示出各种色彩的RGB颜色空间。该颜色传递方法降低了色彩误传现象,提高了颜色传递的准确度并缩短了程序的运行时间。     

分析彩色数字喷墨打印机色彩特性化方法

在当前的发展中,彩色数字打印机色彩特性化再现了对图像设备色彩的描述,是色彩管理中颜色转换的关键,本文从其颜色的空间转换入手,对彩色数字喷墨打印机色彩特性化方法进行了分析。     

基于亮度自适应分段的高动态图像色调映射算法

高动态范围图像(High Dynamic Range Image,HDRI)反映了真实场景的亮度值范围,具有较大的动态范围,而传统的显示设备的动态范围较低.若将高动态范围图像直接压缩到低动态范围显示设备时,可能会导致图像失真、细节丢失等问题.为解决上述问题,本文提出一种基于亮度自适应分段式的色调映射算法.首先,将高动态范围图像从RGB彩色空间转化到CIE XYZ彩色空间,使得亮度信息和彩色信息分离,并只对亮度信息进行处理且不改变颜色信息.其次,以对数亮度平均值作为关键值,从而得到划分区间段的低光区阈值和高光区阈值.然后,针对不同阶段亮度值的特点采用不同的亮度压缩算法,获得新的亮度分量.最后,恢复颜色信息,得到低动态范围图像.实验结果表明,本文的色调映射算法得到的结果整体亮度和细节效果较好.     

基于PCA的相机响应函数模型标定算法

许多计算机视觉应用的算法都需要对拍摄场景高动态范围的幅亮度信息进行精确的测量,成像系统的相机响应函数能够建立拍摄图像强度信息与场景辐亮度之间的严格映射关系,是高动态范围图像融合的关键技术。文中分析相机响应曲线的共同特点,结合相机响应函数固有的约束条件,建立相机响应函数的理论空间模型。首先,利用主成分分析法对已有的相机响应数据库进行分析,结合相机响应函数的约束条件建立响应函数的低参数经验模型;然后,根据输入图像选择合适的参数数量;最后,利用不同曝光量的输入图像通过最小二乘法求解建立响应函数模型的系数,从而对相机响应函数进行标定。该算法能够通过对少量的采样点进行插值获得精确的相机响应函数,同时能够对任意的场景通过拍摄多曝光量图像精确地标定相机响应函数。通过对实际拍摄的图像进行相机响应函数标定实验,验证了该算法的有效性,并证明该算法保持高精度的同时计算效率也较高。     

基于亮度校正与多空间转换的水下图像增强北大核心CSCD

由于水体环境中光的吸收与散射,导致采集的水下图像存在颜色失真、亮度不均、对比度低等缺点。针对以上缺点,提出了基于亮度校正与多空间转换的水下图像增强方法。首先采用色彩平衡算法对退化图像进行颜色校正;然后将色彩校正的图像从红-绿-蓝(red-green-blue,RGB)空间转换为色调-饱和度-亮度(hue-saturation-value,HSV)空间,用构造出新的二维伽马函数处理V通道,再转回RGB空间;最后对颜色校正图像和亮度校正图像进行加权融合,并将融合图像从RGB空间转换为LAB空间,用限制对比度自适应直方图均衡化算法处理L通道,再转回RGB空间,便得到最终的增强图像。为验证本文算法的有效性,采用主观视觉效果和3种客观指标进行验证。结果表明,本文算法能够有效地校正图像亮度,提高图像清晰度。     

基于DSP的LCoS嵌入式图像投影接口设计

采用ADSP-BF561实现嵌入式系统LCoS投影显示系统接口,该设计方案不需要电平转换和串并转换,重点分析了使用该DSP对图像的输出控制,对图像数据进行了色彩空间转换和梯形校正。在色彩空间转换中,采用色彩空间转换公式将YUV空间图像数据转换为RGB空间图像数据;在梯形校正中,将所得到的RGB图像数据进行插值运算后再进行梯形转换,并将得到的梯形图形与原图形进行了对比。本设计实现简单,可以得到在时间资源和空间资源上均达到要求、分辨率为QVGA的投影图像,具有可编程图像处理、可扩展和低功耗的特点。     

相机响应函数标定算法研究进展

高动态范围成像技术能够避免因为拍摄方向如逆光和曝光量的不同而使图像存在亮度和色差影响真实场景的信息采集,有利于复杂环境下获得更高的成像质量,因此被广泛应用于模式识别、智能交通系统、遥感遥测、军事监视侦察等众多领域,具有重要的研究价值。相机响应函数的标定是高动态范围成像技术的关键步骤,能够获得真实场景的辐照度与获得图像像素值之间的映射关系,从而通过该映射关系获得拍摄的真实场景的高动态范围图像。文章对目前现有的相机响应函数标定算法进行分类总结,可为相机响应函数标定算法的研究思路与方法提供借鉴。Abstract:关键词:Key words:     

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.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first