图像中椒盐噪声去除算法研究

为了有效地去除数字图像中的椒盐噪声,提高图像质量,本文 在分析一些典型消除噪声方法的基础上,给出了一种新的椒盐噪声去除算法。首先,针对椒 盐噪声的特点,设计了一种基于动态窗口和邻域像素统计信息的噪声检测算法,有效地区分 了噪声点与非噪声,然后对检测出的噪声点,采用改进的自适性的中值滤波算法进行噪声滤 除,在滤波算法中加入了窗口大小自适应控制和滤波值调优策略。实验表明：该方法不仅能 去除图像中的椒盐噪声,而且能有效地保护图像的细节特征,对于高密度噪声的图像去 除噪声的效果比其他方法更优。     

结合同场景立体图对的高质量深度图像重建

目的 越来越多的应用依赖于对场景深度图像准确且快速的观测和分析,如机器人导航以及在电影和游戏中对虚拟场景的设计建模等.飞行时间深度相机等直接的深度测量设备可以实时的获取场景的深度图像,但是由于硬件条件的限制,采集的深度图像分辨率比较低,无法满足实际应用的需要.通过立体匹配算法对左右立体图对之间进行匹配获得视差从而得到深度图像是计算机视觉的一种经典方法,但是由于左右图像之间遮挡以及无纹理区域的影响,立体匹配算法在这些区域无法匹配得到正确的视差,导致立体匹配算法在实际应用中存在一定的局限性.方法 结合飞行时间深度相机等直接的深度测量设备和立体匹配算法的优势,提出一种新的深度图像重建方法.首先结合直接的深度测量设备采集的深度图像来构造自适应局部匹配权值,对左右图像之间的局部窗立体匹配过程进行约束,得到基于立体匹配算法的深度图像;然后基于左右检测原理将采集到的深度图像和匹配得到的深度图像进行有效融合;接着提出一种局部权值滤波算法,来进一步提高深度图像的重建质量.结果 实验结果表明,无论在客观指标还是视觉效果上,本文提出的深度图像重建算法较其他立体匹配算法可以得到更好的结果.其中错误率比较实验表明,本文算法较传统的立体匹配算法在深度重建错误率上可以提升10％左右.峰值信噪比实验结果表明,本文算法在峰值信噪比上可以得到10 dB左右的提升.结论 提出的深度图像重建方法通过结合高分辨率左右立体图对和初始的低分辨率深度图像,可以有效地重建高质量高分辨率的深度图像.     

不确定需求和配送时间窗约束下的供应链优化

供应链中生产配送的协调对于生鲜食品有重要作用.为解决不确定需求下生鲜食品的生产配送联合决策问题,考虑生鲜食品的送达需满足零售商的硬时间窗;同时商品一旦送达就会产生腐坏,而供小于需也有缺货成本.研究构建了一种数学模型来考虑生鲜食品的生产配送,采用改进的蚁群算法求车辆路径问题,迭代解带入目标函数,再采用Nelder-Mead单纯形法求生产调度,从而得到总优化成本.结果表明,采用集成决策时,供应链中生产和配送成本有较大幅度下降,但同时车辆启动成本的存在会使目标成本出现转折点.实验结果表明了模型的正确性和算法的良好性能.     

虚拟现实场景中三维建模技术研究

三维建模是虚拟仿真系统设计的基础,本文以校园场景为研究对象,讨论了基于校园的三维建模流程,并从如何提高三维建模中的逼真度和建模效率几个方面进行了论证。     

一种图像的连续性边缘提取方法

图像边缘提取是图像处理领域的重要环节,边缘提取的连续性显得尤为重要,其结果可以作为语义分割、测量的基础,为此提出一种图像的连续性边缘提取方法。首先采用卡尼(Canny)算法完成图像的边缘检测,得到粗分割结果。由于该类算法采用算子进行操作,不可避免地产生非连续性区域,因此利用两类模板对粗分割结果进行形态学膨胀操作,连续性边缘采用小半径膨胀,边缘末端采用大半径膨胀,以此构成一幅膨胀图连接这些非连续性区域。最后,将该膨胀图作为平均曲率运动(MCM)方程嵌入函数u的初始值,通过引入g函数在原图中进行迭代求解,完成图像边缘的连续性提取。实验结果验证了算法的实用性与有效性。     

一种可验证的多候选人电子投票方案

电子投票相对传统投票具有安全、便捷、低成本的优势,近年来得到了广泛的关注。2012年孙培勇等人提出了基于多方求和的多候选人电子投票方案。经分析发现该方案不满足可验证性,给出了一种具有可验证性的多候选人电子投票方案,保证计票结果的不可欺骗性。     

公交车的远卡自动收费系统设计

在对公交收费系统的发展和无线射频识别技术进行研究的基础上,分析了现行公交收费系统的优缺点与局限性,并提出了一种公交车远卡自动收费系统的设计思路.主要使用ARM核芯片STM32、射频芯片nRF24LE1等器件,完成了硬件设计.在软件设计上实现了自动计算票价的扣费机制.该系统创新性地将远距离射频技术应用在公交收费系统中,不仅方便了乘客,而且大大提高了乘客上下车的效率.     

Semiglobal stabilization of saturated linear systems via multiple parametric Lyapunov equations

This paper investigates the problem of semiglobal stabilization with guaranteed flexible pole placement for saturated linear systems. To retain the advantages of the parametric Lyapunov equation, matrix‐partitioning idea is used to derive a new pole shift lemma. Starting from system matrix transformations, a recursive algorithm is proposed to shift every eigenvalue of a linear system separately without mode decomposition in each step. A new method introducing various parameters to every Lyapunov equation in each step is presented. As an application, the semiglobal stabilization with guaranteed flexible pole placement for saturated linear systems can be achieved by this method. Finally, its effectiveness and advantages are demonstrated via a simulation example. Copyright © 2013 John Wiley & Sons, Ltd.     

Novel ultra‐compact two‐dimensional waveguide‐based metasurface for electromagnetic coupling reduction of microstrip antenna array

A novel ultracompact two‐dimensional (2D) waveguide‐based metasurface is proposed herein and applied for the first time to reduce mutual coupling in antenna array for multiple‐input multiple‐output applications. The unit cell of the proposed 2D waveguide‐based metasurface is ultracompact (8.6 mm × 4.8 mm, equal to λ₀/14.2 × λ₀/25.5) mainly due to the symmetrical spiral lines etched on the ground. The metasurface exhibits a bandgap with two transmission zeros attributing to the negative permeability in the vicinity of magnetic resonance and the negative permittivity in the vicinity of electric resonance. Taking advantage of these two features, a microstrip antenna array is then designed, fabricated, and measured by embedding an 8 × 1 array of the well‐engineered 2D waveguide‐based metasurface elements between two closely spaced (9.2 mm, equal to λ₀/13.3) H‐plane coupled rectangular patches. There is good agreement between the simulated and measured results, indicating that the metasurface effectively reduces antenna mutual coupling by more than 11.18 dB and improves forward gain. The proposed compact structure has one of the highest reported decoupling efficiencies among similar periodic structures with comparable dimensions. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:789–794, 2015.     

Output performance optimization for RTD fluxgate sensor based on dynamic permeability基于动态磁导率参数的时间差型磁通门传感器的输出响应优化

The output performance of residence times difference (RTD) fluxgate may vary under different driving conditions (driving currents and frequencies) and core materials. To optimize the RTD fluxgate and simplify its design process, an analytical model is employed to select the parameters and identify the effective factors that dominate the performance. The dynamic permeability parameters (P_i), which reflect the changes in the magnetization curve, are mathematically analyzed in detail. The linear variation functions of P_i in different driving conditions are fitted by using the dynamic arctangent hysteresis model. Consequently, the selection of driving conditions and core materials, which are assessed by comparing the experiment and simulation results, has an important role in achieving the optimal output performance of the RTD fluxgate.