基于改进Rank变换和分段MER的镜片疵病检测算法

为了解决目前光学镜片表面疵病宽度测量主要依赖人工检测而导致弯曲划痕宽度检测精度较低的问题,提出一种基于Rank变换和分段最小外接矩形(MER)的镜片表面划痕宽度测量方法.该方法首先通过改进的Rank变换算法比较像素灰度相对关系来提取疵病目标,然后计算其最小外接矩形,根据矩形长宽比初步判别疵病类型(划痕或麻点),最后将疵病分割为多个小区段,分别计算每段的最小外接矩形并获得其宽度,比较取最大宽度作为疵病宽度值.试验结果表明,该方法具有较高的可行性与精确性,能够有效提取出疵病和计算其特征参数,可以满足工程实际的需要.     

基于PSO算法的运动目标跟踪研究

提出一种基于PSO的运动目标跟踪方法,并在TMS320DM642上实现.该方法首先针对采集到图像的Y分量通过帧间差分和背景差分相结合的方法建立背景模型,然后检测出前景运动目标,接着通过前景运动目标初始化目标模板,再对目标模板和待跟踪视频图像分别进行两次金字塔降采样,降低目标模板和待跟踪视频图像的分辨率.在顶层金子塔上采用粒子群优化算法对跟踪目标进行粗定位,在中间层和底层金字塔上采用钻石搜索方法对跟踪目标进行精确定位.在目标跟踪的过程中,目标模板随运动目标的变化而不断更新,实现对目标的实时连续性跟踪.该方法可以有效降低计算复杂度,提高搜索效率.     

基于行为检测的非法VOIP探测研究

VOIP以其高效、快捷、节约通信费用的特性,被越来越广的应用到人们生产、生活等方面。受利益等因素的驱动,越来越多的非法VOIP隐藏在广袤的互联网中。这些非法VOIP的设置者不但经营不合法,往往还会利用VOIP落地网关透传性等漏洞,进行敲诈、诈骗等犯罪活动,危害人民群众财产安全。研究现行法律法规及VOIP的技术原理,找出非法VOIP在互联网中的行为特点,针对这些特点建立有效检测模型,最终认定非法VOIP网关是打击非法设立VOIP的核心基础。     

无线地磁技术在城市交通管理方面的应用

地磁传感器通过探测车辆通过时对地球磁场产生的扰动来检测车辆,再加上安装方便、不受环境影响等诸多优势,无线地磁技术在智能交通领域和停车管理系统中发挥了越来越重要的角色。     

A destination-based approach for cut detection in wireless sensor networks

Wireless sensor networks often suffer from disrupted connectivity caused by its numerous aspects such as limited battery power of a node and unattended operation vulnerable to hostile tampering. The disruption of connectivity, often referred to as network cut, leads to ill-informed routing decisions, data loss and waste of energy. A number of protocols have been proposed to efficiently detect network cuts; they focus solely on a cut that disconnects nodes from the base station. However, a cut detection scheme is truly useful when a cut is defined with respect to multiple destinations (i.e. target nodes), rather than a single base station. Thus, we extend the existing notion of cut detection, and propose an algorithm that enables sensor nodes to autonomously monitor the connectivity to multiple target nodes. We introduce a novel reactive cut detection solution, the point-to-point cut detection, where given any pair of source and destination, a source is able to locally determine whether the destination is reachable or not. Furthermore, we propose a lightweight proactive cut detection algorithm specifically designed for a network scenario with a small set of target destinations. We prove the effectiveness of the proposed algorithms through extensive simulations; specifically, in our network configurations, proposed cut detection algorithms achieve more than an order of magnitude improvement in energy consumption, when coupled with an underlying routing protocol.     

MALDI-TOF MS: an upcoming tool for rapid detection of antibiotic resistance in microorganisms

MALDI-TOF MS profiling for microorganism detection has already been demonstrated in the 1990s, but has evolved to the first-line identification method in many laboratories just during the past five years. While this application of MALDI-TOF MS has proven its broad applicability, accuracy, robustness, and cost-effectiveness it is of particular interest to expand the capabilities of the mass spectrometric platform. Resistance detection is the most desirable further application of MALDI-TOF MS in microbiology, but maybe also the most challenging. Different approaches have been published regarding diverse antibiotic drugs and distinct microorganism classes. The current review shall give an overview about the developments of the recent years and their potential to get transformed in clinical useful assays in the future.     

无线传感器网络技术在海洋平台结构安全检测领域的应用研究

无线传感器网络能够很好地解决海洋平台结构检测中遇到的很多问题。对无线传感器网络这一无线通信中的热点领域在无线传感器网络体系构架、大规模组网技术及网络管理、环境感知技术、数据采集技术以及信息处理技术等方面进行了应用研究,以期能将该项技术应用于我国海洋平台结构的安全检测中。     

Variance sensitive adaptive threshold-based PCA method for fault detection with experimental application

Principal Component Analysis (PCA) is a statistical process monitoring technique that has been widely used in industrial applications. PCA methods for Fault Detection (FD) use data collected from a steady-state process to monitor T² and Q statistics with a fixed threshold. For the systems where transient values of the processes must be taken into account, the usage of a fixed threshold in PCA method causes false alarms and missing data that significantly compromise the reliability of the monitoring systems. In the present article, a new PCA method based on variance sensitive adaptive threshold (T_vsa) is proposed to overcome false alarms which occur in the transient states according to changing process conditions and the missing data problem. The proposed method is implemented and validated experimentally on an electromechanical system. The method is compared with the conventional monitoring methods. Experimental tests and tabulated results confirm the fact that the proposed method is applicable and effective for both the steady-state and transient operations and gives early warning to operators.     

基于主成分迭代支集检测的多对比度 磁共振快速成像

很多磁共振成像应用(如 T1、T2 参数成像)需要连续采集一系列不同对比度的图像。丰富的对比度机制反映了 人体组织的内在特性,为临床提供了有效的定量诊断手段。然而,由于扫描时间过长,这种方法在临床上的应用受到一 定的限制。近几年兴起的压缩感知理论在磁共振快速成像方面显示了巨大的潜能。其中,学者们提出一种基于主成分分 析的快速磁共振成像方法。该方法从已知的解析物理模型和参数范围中训练主成分,并通过截断的方式利用图像序列的 时域稀疏性。但是,当这种截断先验信息不准确时,上述方法可能会产生模型误差。 本文通过采用迭代支集检测的方法 实现主成分系数支集的适应性估计。文章最后通过两组人体膝盖数据的重建实验,验证了该方法的有效性。     

Coherent microscopy by laser optical feedback imaging (LOFI) technique

The application of the non-conventional imaging technique LOFI (laser optical feedback imaging) to coherent microscopy is presented. This simple and efficient technique using frequency-shifted optical feedback needs the sample to be scanned in order to obtain an image. The effects on magnitude and phase signals such as vignetting and field curvature occasioned by the scanning with galvanometric mirrors are discussed. A simple monitoring method based on phase images is proposed to find the optimal position of the scanner. Finally, some experimental results illustrating this technique are presented.