一种基于噪声连接分量的层次中值滤波算法

针对椒盐噪声污染图像的降噪,提出一种基于噪声连接分量的层次中值滤波新算法。该算法首先根据椒盐噪声像素点的邻接关系和分布特点,对噪声定位图像实施标记处理;然后通过计算各连接分量集合中元素的个数,将噪声定位图像分层,得到层次噪声定位图像;最后按照由低层到高层的顺序,逐层对噪声污染图像进行标准中值滤波处理,最终得到滤波结果。将该算法与标准中值滤波、自适应中值滤波进行仿真对比实验,并与其他类型中值滤波算法就指标PSNR(Peak Signal Noise Ratio)进行比较,均表明该算法降噪效果优良。

基于标注连接分量的二值水印图像重构

水印图像的提取是组成水印系统的重要部分。一般情况下,提取的水印都是在含水印图像在遭受一定的攻击后提取的,因此,提取的水印图像会有不同程度的噪音在里面,为了提高提取的水印图像的视觉质量,本文提出了一种基于标注对象的二值水印图像的重构算法。首先将水印图像的所有连接分量标注出来,然后计算每个连接分量包含的元素的数目;因为噪音一般都是孤立的元素,所以将数目最小的连接分量中的所有元素置为0,通过不断的循环直至水印图像中的连接分量等于原始水印图像数目为止。实验结果证明,本算法效果良好。

一种基于噪声连接分量的自适应层次中值滤波算法

针对椒盐噪声污染图像的降噪,提出一种基于噪声连接分量的自适应层次中值滤波算法。首先根据椒盐噪声像素点的邻接关系和分布特点,对噪声定位图像实施标记处理;然后计算各连接分量集合中元素的个数,将噪声定位图像分层,得到层次噪声定位图像;最后按照由低层到高层的顺序,逐层对噪声污染图像进行标准中值滤波处理,而标准中值滤波的窗口大小则依据连接分量自适应地进行调整,最终得到滤波结果。将该算法与标准中值滤波、自适应中值滤波进行仿真实验,并与其他中值滤波算法就指标PSNR进行比较,均表明该算法降噪效果优良。

几种重要的HDTV连接端子

现在,电视已进人数字年代,人们可以毫不费力地从有线电视网和卫星系统收看几百套电视节目.在许多城市内,数字高清晰度电视(HDTV)广播也与模拟电视一起并行发展,并且会将模拟电视淘汰出局.

一种基于非线性滤波算法的厚膜电路视觉检测系统的实现

在厚膜电路生产中需要利用人工通过显微镜对基片上电路的短路、断路的质量问题进行识别,笔者在一个厚膜电路视觉质量检测设备的开发项目中提出了利用非线性滤波算法以及膨胀、腐蚀、细化等图像形态处理的方法得到被测电路的骨骼化图像,然后通过统计线路和基片骨骼化图像的连接分量的数量判断电路的短路和断路问题,该方案在实际中使用良好,大大提高了厚膜电路的检测效率与产品质量。

Impacts of Packet Collisions on Link Throughput in CSMA Wireless Networks

It is known that packet collisions in wireless networks will deteriorate system performance, hence substantial efforts have been made to avoid collision in multi-user access designs. Also, there have been many studies on throughput analysis of CSMA wireless networks. However, for a typical CSMA network in which not all nodes can sense each other, it is still not well investigated how link throughputs are affected by collisions. We note that in practical 802.11-like networks, the time is divided into mini-timeslots and packet collisions are in fact unavoidable. Thus, it is desirable to move forward to explore how collisions in such a network will affect system performance. Based on the collision-free ideal CSMA network(ICN) model, this paper attempts to analyze link throughputs when taking the backoff collisions into account and examine the effect of collisions on link throughputs. Specifically, we propose an Extended Ideal CSMA Network(EICN) model to characterize the collision effects as well as the interactions and dependency among links in the network. Based on EICN, we could directly compute link throughputs and collision probabilities. Simulations show that the EICN model is of high accuracy. Under various network topologies and protocol parameter settings, the computation error of link throughputs using EICN is kept to 4% or below. Interestingly, we find that unlike expected, the effect of collisions on link throughputs in a modest CSMA wireless network is not significant, which enriches our understanding on practical CSMA wireless networks such as Wi-Fi.

Knotted Picture of a Quantum Network of Two Nodes

This article discusses the variation of the knotted picture of the quantum pure state with the variation of the complex coefficients α and β. It is shown that there are three kinds of link that correspond to three different ranks of the matrix of covariance correlation tensor, i.e., the zero rank corresponds to trivial link, the rank one corresponds to the two-component link with two crossings, and the rank three corresponds to the two-component link with four crossings.

A Quantitative Structure Property Relationship for Prediction of Flash Point of Alkanes Using Molecular Connectivity Indices

Many structure-property/activity studies use graph theoretical indices, which are based on the topological properties of a molecule viewed as a graph. Since topological indices can be derived directly from the molecular structure without any experimental effort, they provide a simple and straightforward method for property prediction. In this work the flash point of alkanes was modeled by a set of molecular connectivity indices （Х）, modified molecular connectivity indices （ ^mХ^v ） and valance molecular connectivity indices （ ^mХ^v ）, with ^mХ^v calculated using the hydrogen perturbation. A stepwise Multiple Linear Regression （MLR） method was used to select the best indices. The predicted flash points are in good agreement with the experimental data, with the average absolute deviation 4.3 K.

Analysis and Modeling of k-regular and k-connected Protection Structure in Ultra-High Capacity Optical Networks

This paper proposes k-regular and k-connected(k&k) structure against multifaults in ultra-high capacity optical networks.Theoretical results show that pre-configured k&k structure can reach the lower bound on logical redundancy.The switching time of k&k protection structure is as quickly as ringbased protection in SDH network.It is the optimal protection structure in ultra-high capacity optical networks against multi-faults.We develop the linear programming model for k&k structure and propose a construction method for k&k structure design.Simulations are conducted for spare spectrum resources effi ciency of the pre-confi gured k&k structure under multi-faults on representative COST239 and NSFnet topologies.Numerical results show that the spare spectrum resources efficiency of k&k structure can reach the lower bound on logical redundancy in static networks.And it can largely improve spare spectrum resources effi ciency compared with p-cycles based protection structure without reducing protection effi ciency under dynamic traffi cs.

Measurement of Collision Conditions in Magnetic Pulse Welding Processes

MPW （magnetic pulse welding） is a solid state joining technology that allows for the generation of strong metallic bonds, even between dissimilar metals. Due to the absence of external heat, critical intermetallic phases can largely be avoided. In this process, Lorentz forces are utilized for the rapid acceleration of at least one of the two metallic joining partners leading to the controlled high velocity impact between them. The measurement of the collision conditions and their targeted manipulation are the key factors of a successful process development. Optical measuring techniques are preferred, since they are not influenced by the prevalent strong magnetic field in the vicinity of the working coil. In this paper, the characteristic high velocity impact flash during MPW was monitored and evaluated using phototransistors in order to measure the time of the impact. The results are in good accordance with the established PDV （photon Doppler velocimetry） and show a good repeatability. Furthermore, the collision front velocity was investigated using adapted part geometries within a series of tests. This velocity component is one of the key parameters in MPW; its value decreases along the weld zone. With the help of this newly introduced measurement tool, the magnetic pressure distribution or the joining geometry can be adjusted more effectively.

一种基于像素连接性的边缘图像分割方法

针对边缘图像中有效对象的分割,提出一种基于像素连接性的边缘图像分割新方法。该方法首先根据对原始灰度图像进行Canny算法边缘检测,依据边缘图像中有效对象一般具有相对较好像素连接性的特点,对二值边缘图像实施标记处理,选择标记矩阵中具有极大和较大像素连接性的部分,即获取了边缘图像中的有效对象,完成边缘图像中对有效对象的分割处理。人造测试图像和实际灰度图像的仿真实验均表明,此边缘图像的分割方法是有效的。