针对在光电偏振成像模式下缺乏行之有效的水下运动目标探测方法的问题,提出了一种基于水面特征波纹的水下运动目标检测算法。通过海面风生重力波模型和水下运动目标的水面特征波纹模型,仿真得到不同状态下的海面混合波纹图像,用于算法研究及证明;采用Radon变换提取波纹的线性特征,并通过均值滤波和标准归一化处理消除Radon变换对检测的影响;采用双邻域自适应门限法提取Radon变换域中的局部峰值点,利用连续小波
We demonstrate a nonlinearity optimization method by altering distribution of passive fibers in a dissipative-soliton mode-locked fiber laser to level up output parameters. In the numerical simulation, we found that the passive fiber segment after gain fi
Three-dimensional (3D) terahertz (THz) imaging or THz tomography has recently proven to be useful for nondestructive testing of industrial materials and structures. In place of previous imaging techniques such as THz pulsed/continuous-wave radar and THz c
The influence of the fourth-order dispersion coefficient on the behavior of parametric gain and saturation power of a one-pump fiber optical parametric amplifier over a signal wavelength span in the presence of fiber random dispersion fluctuations was inv
We propose, design, and realize a compact stabilized laser system that can be tuned within 24 GHz automatically. This laser system consists of two distributed feedback (DFB) lasers, one of which is reference and locked to the D2 line of
通过选择绿色磷光材料(2’,6’-双(三氟甲基)-2,3’-联吡啶)四苯基亚氨基二次膦酸酯作为发光材料制备一系列的有机发光二极管。同时,4,4',4″-三(咔唑-9-基)三苯胺(TcTa)和9,9'-(2,6-吡啶二基二-3,1-亚苯)双-9H-咔唑(26DczPPy)分别被选为发光层(EMLs)1和2的主体材料,因为它们具有相对匹配的能级和较高的载流子迁移率。通过对单发光层器件与双发光层器件的性能进行分析发现,双发光层器件结构的设计有助于拓宽空穴和电子的复合区间,从而提高电致发光(EL)效率。最后,
Surface-emitting distributed feedback quantum-cascade lasers operating at \lambda \approx 7.8 \mu m are demonstrated. The metal-covered second-order grating is shallow-etched into the surface of a thin InGaAs contact and cladding layer. This forms a hy
针对遥感影像半全局立体匹配(SGM)对噪声敏感及在视差不连续和弱纹理区域产生条纹导致匹配率低的问题,提出一种结合加速鲁棒特征(SURF)的遥感影像SGM算法。首先,用SURF计算遥感影像的特征匹配点和特征点主方向,并用快速最近邻搜索算法剔除错误的匹配点;然后,用Census变换计算两幅遥感影像的匹配代价,用特征点主方向来调整SGM算法在不同聚合路径方向上的路径权重;最后,用改进的加权联合双边滤波(WJBF)方法进行视差精化,以去除视差图中的噪声和条纹。在WorldView、IKONOS、高景一号遥感影像数
对微光机电系统(MOEMS)兴趣的惊人增长吸引了包括众多研发中心和工业企业的投入。大量的MOEMS应用领域为之发展提供巨大机遇,如光通信(光开关,交叉连接矩阵,DWDM系统等)、数字图像处理、自适应光学以及工业维护、环保、生物医疗等等。本文简述MEMS(微机电系统)和MOEMS的概念后,着重介绍MOEMS的应用领域和几种典型器件。采用MEMS工艺技术制备出诸如DWDM通信系统用的可调谐F-P干涉仪或用于障碍物探测的二维扫描器等器件。已开发出多种专用技术,制备成功应用于障碍物检测的二氧化硅一维扫描器件。另外