Recovery of Surface Reflectances Using Video Camera Image Signals under Unknown Illuminations

Estimation of surface spectral reflectance functions and colorimetric values of object colors was carried out for the image data captured by video camera under unknown illuminations. The estimation method is based on the finite-dimensional linear model of illuminants and surfaces using a single reference reflectance with known surface spectral reflectance in a scene. Experimental results showed that recovered surface spectral reflectance functions are the almost same for different illuminations. This method is useful for the colorimetric calibration of the devices, since any set of orthonormal basis vectors to represent illuminations and any set of eigen vectors derived from principal component analysis on the data set of a color chart to express surfaces of different objects can be applied to the estimation. The recovered surface reflectances were evaluated by color differences in CIE L*a*b* color space.     

GPS姿态测量中相位模糊的解算方法

文中从GPS姿态测量原理出发，讨论了解决相位模糊这一关键问题，首先讨论了采用有限基线长度或相位平滑伪距值来确定相位模糊搜索空间，然后利用存在的冗余相位观测量采用相位残差及基线长度统计检验对相位整周模糊向量进行搜索，最后得到唯一正确的整周模糊向量，进而可解算出对应的基线矢量，从而得到载体姿态。利用上述方法对GPS实测数据进行处理，可在较短时间内解决相位模糊问题。     

光纤通信系统中的时钟信号恢复

时钟信号恢复是光纤通信中的一个非常重要的内容，它是实现有效和可靠通信的基础。为此介绍了几种时钟信号恢复方法的原理并结出了相应电路图，最后简要分析了这些时钟信号恢复方法的应用范围。     

On the comparison of four different implementations of a third-order ENO scheme of box type for the computation of compressible flow

Following ideas of Abgrall, four different implementations of a third-order ENO scheme on general triangulations are described and examined. Two implementations utilize implicit time stepping where the resulting linear systems are solved by means of a preconditioned GMRES method. Two other schemes are constructed using an explicit Adams method in time. Quadratic polynomial recovery is used to result in a formally third-order accurate space discretisation. While one class of implementations makes use of cell averages defined on boxes and thus is close in spirit to the finite volume idea, the second class of methods considered is completely node-based. In this second case the interpretation as a true finite volume recovery is completely lost but the recovery process is much simpler and cheaper than the original one. Although one would expect a consistency error in the finite difference type implementations no such problem ever occurred in the numerical experiments.Dedicated to Willi Törnig on the occasion of his 65th birthday     

重复率气体火花开关绝缘恢复特性

在自行设计的气体火花开关上，利用双脉冲回路，对纳秒脉冲作用下Ｎ２和Ｈ２的绝缘恢复特性进行了实验研究。结果表明，在静态不吹气情况下，Ｈ２的绝缘恢复时间明显比Ｎ２短。在吹气情况下，适当的气流速度即可使绝缘恢复时间明显缩短。     

VLSI三维寄生电容提取的层次式h-自适应计算

在基于直接边界元素法的层次式h-自适应计算中,改进了层次式边界元的自动加密方法,提高了计算可靠性.同时,将基于超收敛恢复技术的误差指示器实现于在常数元基础上叠加层次锥函数的寄生电容自适应计算,提出一种在不同阶次边界元上使用恢复技术的方法.与同类软件相比,计算稳定,收敛速度较快.     

SYNCHRONIZATION RECOVERY SCHEME IN WATERMARKING DETECTION

Most proposed digital watermarking algorithms are sensitive to geometric attacks because the synchronization information of watermark embedding and detection is destroyed. In this letter a novel synchronization recovery scheme based on image normalization is proposed. The presented scheme does not require the original image and can be applied to various watermark systems. A wavelet-based watermarking scheme is proposed as an example and experimental results show that it is robust to geometric attacks.     

电信网络的业务连续性和灾难恢复计划及服务(下)

业务连续性(BC)和灾难恢复(DR)计划简称BCDR计划，是朗讯科技全球服务部与国信朗讯科技网络技术有限公司联合在国内推出的一种全新电信服务理念。目的在于把朗讯科技贝尔实验室多年来支撑国外大型电信运营商网络运行管理的经验和为网络灾难恢复方案设计开发的一些工具和网络监控系统，引入到我国电信网络管理中，     

40 Gbps All‐Optical 3R Regeneration and Format Conversion with Related InP‐Based Semiconductor Devices

We report an experimental demonstration of 40 Gbps all‐optical 3R regeneration with all‐optical clock recovery based on InP semiconductor devices. We also obtain all optical non‐return‐to‐zero to return‐to‐zero (NRZ‐to‐RZ) format conversion using the recovered clock signal at 10 Gbps and 40 Gbps. It leads to a good performance using a Mach‐Zehnder interferometric wavelength converter and a self‐pulsating laser diode (LD). The self‐pulsating LD serves a recovered clock, which has an rms timing jitter as low as sub‐picosecond. In the case of 3R regeneration of RZ data, we achieve a 1.0 dB power penalty at 10^?9 BER after demultiplexing 40 Gbps to 10 Gbps with an eletro‐absorption modulator. The regenerated 3R data shows stable error‐free operation with no BER floor for all channels. The combination of these functional devices provides all‐optical 3R regeneration with NRZ‐to‐RZ conversion.     

基于MPEG-2码流的DC错误检测与恢复

基于ＭＰＥＧ－２标准的错误检测和隐藏是视频领域研究的一个重点，而直流系数的铬误检测与隐藏尚属空白。本文从分析直流系数的错误特点出发，根据图像空域的相关性，首次提出了完整的ＤＣ系数错误检测和恢复算法，并通过实验对算法进行了验证，取得了满意的效果。