机器视觉技术在交通路标识别中的实现方法

介绍了机器视觉技术在交通路标识别中的应用。路标区域的分割主要依据路标颜色在HSI颜色空间的类聚特征,路标指示的识别采用基于尺度不变特征提取算法的模板匹配来实现。     

未知环境中基于视觉的增量式拓扑建模及导航

针对未知环境提出并实现了一个新的基于摄像机视觉的增量式拓扑建模及导航系统.该系统包括自然路标提取、建模与定位、地图及路标库管理、规划4个主要部分.采用局部显著图像区域构造自然路标,并利用隐马尔科夫模型(HMM)建模当前场景中所获得路标间的关系,构造拓扑顶点.为提高定位精度,设计了最大后验概率(MAP)的学习策略.设计了基于竞争学习的路标管理机制,采用简单的最短路径算法在拓扑图上进行路径规划.该系统支持在线增量式建模,利用局部图像特征及其关系表示环境,定位算法简洁有效,辅以路标管理使之能够适应大规模环境导航任务.实验结果表明该系统路标提取稳定、位置识别率高、定位精确,能够保证机器人在未知环境中的安全导航.     

一种新的被动融合定位方法

提出了一种通过综合多部声呐信息实现被动高精度定位的新算法．该算法通过使用高精度DOA估计结果。并对多阵三角定位后形成的初估值空间区域进行峰值搜索，提高了被动定位的精度．仿真试验表明：算法定位迅速。且精度较常规方法有了较大提高，适用于对较近距离的目标进行精确定位。     

股骨颈空心钉手术机器人定位算法误差分析

针对股骨颈骨折空心钉手术中的空间定位问题,提出了一种基于射影变换的双平面空间定位算法,并为其建立了数学模型;在此基础上,采用蒙特卡罗法对定位算法的精度进行了理论推导,并用Matlab对系统精度进行了仿真,对仿真结果进行了分析,得到了系统精度;分组比较了定位算法中各输入量对算法精度的影响程度,并对误差分布规律进行仿真,得到误差分布规律.仿真发现当目标点处于两参考坐标系平面之内,且标记点靠近X光发射源时精度较高,本文依据上述分析结果从标尺结构、图像采集和物理量的优化等方面提出定位算法修改建议.     

主动全向声纳浮标定位算法和定位误差研究

针对主动全向声纳浮标定位目标算法和定位误差问题,依据"纯距离测量"定位的最小二乘算法,给出了定位误差方差阵的迭代计算方法和计算流程.采用蒙特卡洛仿真方法,统计分析了定位算法的精度;对比分析了定位误差均方差理论计算值和目标位置仿真结果的均方根误差,给出了定位算法的精度,验证了定位误差算法的正确性.     

改进萤火虫算法优化粒子滤波的信号源定位

为提高无线电信号源的定位精度,运用粒子滤波方法对其进行定位估计。针对粒子滤波存在的粒子退化问题,提出改进的萤火虫算法优化粒子滤波。首先对萤火虫算法的吸引度公式进行改进,并利用迭代时刻粒子最优值指导个体的移动过程。然后运用改进的萤火虫算法与粒子滤波机制相结合,使粒子趋向于高似然区域,提高粒子的有效性,避免粒子退化,提高粒子滤波算法的滤波精度。最后,将改进后的算法用于无线电信号源定位算法中并进行仿真试验。实验结果表明:该文提出的算法定位结果最大定位误差为0.23%,该算法相比粒子滤波算法的定位精度有很大的提高,是一种有效的、实用性较强的定位估计算法。     

基于模糊神经网络的包装机械臂定位方法研究

目的 为提高包装机械臂的抓取精度,文中基于模糊神经网络设计一种包装机械臂定位方法。方法 将激光测距仪与工业相机融合,可实现目标点的初步定位并得到位姿偏差。以机械臂末端位置误差补偿为例,设计一种模糊神经网络控制器,可实现PID控制关键参数的在线调整以提高误差补偿精度。进一步地,采用果蝇优化算法实现神经网络控制器初始值的优化,可提高控制系统性能。最后,进行实验研究。结果 实验结果表明,机械臂定位算法可使最大绝对误差从7.704 9 mm下降到1.424 2 mm;平均绝对定位误差降低约82.5%;机械臂执行效率与对照组相当。结论 该定位方法可以大幅度提高包装机械臂定位精度,可满足包装、化工、食品等相关行业要求。     

基于Chan与Geiger混合算法的声发射源定位方法

Geiger定位算法是一种广泛应用的岩石损伤声发射源定位方法,但该算法受初始值影响较大,直接影响了算法的应用效果。文章充分挖掘Chan算法的特性,提出了一种混合Chan与Geiger算法的优化算法,利用Chan算法对损伤声源进行初始定位,再融合Geiger算法进行迭代解算。通过数值计算和断铅实验对所提出的混合算法进行理论分析和实验验证,结果表明：该混合算法简便、易行、结果可靠,能够有效提升声发射源定位算法的收敛速度和定位精度;在传感器数量较少时,该混合算法具有较强的适应性;在布设4个单维传感器的条件下,Chan与Geiger混合算法较最小二乘法与Geiger混合算法,定位结果更加精确,且迭代次数更少,能有效提高计算效率。该研究对于提高岩石、混凝土材料的损伤定位和健康监测的测算精度以及工作效率具有一定的促进意义。     

超声速运动目标被动声定位算法的后置处理

超声速运动目标在空气中习行时产生激波,前文＾「１」利用激波到达时间提出一种基于波前方向矢量的定位算法,本文着重分析该定位算法的理论估计精度。提出一种基于数据融合的后置处理算法,以提高估计精度。     

卡尔曼滤波在水雷引信目标定位中的应用

介绍了用于水雷引信的目标跟踪定位卡洋曼滤波算法,推导了滤波公式,给出了仿真结果,经分析得知,利用该算法可有效提高目标运动要素估计精度。     

Optimized gating scheme for rapid lifetime determinations of single-exponential luminescence lifetimes

The rapid lifetime method (RLD) for determining excited-state lifetimes uses the ratio of the areas under two regions of the decay. To get good precision with the standard method, prior knowledge of the lifetime is essential to selecting the integration regions. As will be shown, the usual method of selecting integration regions is far from optimal. An optimal gating scheme that is more precise and much more forgiving in the selection of integration region than any of the prior methods will be shown. Monte Carlo simulations were performed to determine the optimal gating. Experimental data was used to confirm the capabilities of the optimized RLD. The speed of the optimal RLD is similar to the standard RLD but without the necessity of matching the integration interval to the lifetime for precise results.     

王冠虫化石三维数字建模与几何形态测量

基于结构光扫描方法,实现王冠虫化石空间形貌特性精密测量.经过形貌扫描、数据采集、整合拼接等步骤,建立王冠虫化石三维数字模型.利用数字模型,通过局部最小二乘法,得到具有典型几何形态特征的关联直线,再通过直线相交获得几何标志点的精确空间位置,进而得到王冠虫化石的精密几何形态信息,如标志点间距离、间肋沟与背沟夹角、近三角形尾甲处轴叶各边长与角度等.采用万能工具显微镜与王冠虫化石数字模型进行对比测量,距离测量精度优于0.1 mm,角度测量精度优于1'.     

带标志点的LTSA算法及其在轴承故障诊断中的应用

针对非监督式流形学习算法面临的增量式学习问题,提出一种带标志点的增量式局部切空间排列算法.该方法在局部切空间排列算法的基础上,利用最小角度回归算法从原始训练样本中选取标志点,以选取的标志点和新增样本建立所有样本的全局坐标矩阵,利用原始样本低维嵌入坐标和全局坐标矩阵对新增样本的低维嵌入坐标进行估计,并采用全局坐标矩阵特征值迭代方法更新所有样本的低维嵌入坐标.滚动轴承4种不同状态振动数据样本的增量式识别结果表明,本方法在实现局部切空间排列算法增量式学习的基础上,保持了对滚动轴承不同状态样本较高的类别可分性测度.     

Street-Level Landmarks Acquisition Based on SVM Classifiers

High-density street-level reliable landmarks are one of the important foundations for street-level geolocation. However, the existing methods cannot obtain enough street-level landmarks in a short period of time. In this paper, a street-level landmarks acquisition method based on SVM (Support Vector Machine) classifiers is proposed. Firstly, the port detection results of IPs with known services are vectorized, and the vectorization results are used as an input of the SVM training. Then, the kernel function and penalty factor are adjusted for SVM classifiers training, and the optimal SVM classifiers are obtained. After that, the classifier sequence is constructed, and the IPs with unknown service are classified using the sequence. Finally, according to the domain name corresponding to the IP, the relationship between the classified server IP and organization name is established. The experimental results in Guangzhou and Wuhan city in China show that the proposed method can be as a supplement to existing typical methods since the number of obtained street-level landmarks is increased substantially, and the median geolocation error using evaluated landmarks is reduced by about 2 km.     

A Novel Technique for Estimating the Numerical Error in Solving the Helmholtz Equation

In this study, we applied a defined auxiliary problem in a novel error estimation technique to estimate the numerical error in the method of fundamental solutions (MFS) for solving the Helmholtz equation. The defined auxiliary problem is substituted for the real problem, and its analytical solution is generated using the complementary solution set of the governing equation. By solving the auxiliary problem and comparing the solution with the quasianalytical solution, an error curve of the MFS versus the source location parameters can be obtained. Thus, the optimal location parameter can be identified. The convergent numerical solution can be obtained and applied to the case of an unavailable analytical solution condition in the real problem. Consequently, we developed a systematic error estimation scheme to identify an optimal parameter. Through numerical experiments, the optimal location parameter of the source points and the optimal number of source points in the MFS were studied and obtained using the error estimation technique.     

Evaluating the bandwidth of an if amplifier in a superheterodyne attenuation meter

Conclusions A superheterodyne attenuation meter, the bandwidth of whose IF amplifier is selected to reduce the random error in measuring a given maximum attenuation, provides smaller random and systematic measurement errors than a meter the bandwidth of whose IF amplifier is selected to provide equal random error components due to frequency instability and thermal noise. Errors in measuring low and medium attenuations will also be smaller with the above method of selecting the IF amplifier's bandwidth, i.e., this bandwidth will be optimum.Translated from Izmeritel'naya Tekhnika, No. 5, pp. 29–31, May, 1967.     

遗传算法用于衍射光学元件的优化设计

提出了一种基于遗传算法的衍射光学元件优化设计方法;在衍射光学元件设计中遗传算法运行参数对遗传算法性能有一定的影响:采用较大的群体规模,遗传算法越容易获得最优解;交叉算子越大,遗传算法全局搜索能力越强;选择算子对遗传算法的影响不是太大;如果要进一步提高解的精度,可选取较大的终止代数。数值计算结果表明,用遗传算法优化设计的衍射光学元件,其误差小于 5.2%,衍射效率达到 91.2%。遗传算法很适合衍射光学元件的优化设计。     

Temperature coefficient of sensitivity dependence of themeasurement error of quartz crystal resonators

This paper discusses the measurement error of quartz crystal resonators (QXRs) vs. the temperature coefficient of force sensitivity. Based on the analysis of the difference between the temperature coefficient of frequency and the temperature coefficient of force sensitivity, the measurement error formula is deduced. According to the error formula, the physical significance of the temperature coefficient of force sensitivity is explained, and the method of selecting a scale temperature is given. The measurement error formula has been verified recently by experimental results. To expand the selectable range of cut modes and to compare the performances of QXRs, the selecting principle of the best group of the angles of cut of quartz crystal plate, &thetas;, ϑ, and azimuth angle of applied force, ψ is given simultaneously. According to the measurement error formula and the selecting principle of the best group of the angles, the best azimuth angle of AT-cut used as force sensitive resonators is found through the analysis of the measurement error. This paper provides a theoretical basis on which the measurement accuracy of QXR force sensors can be improved     

Selecting Test Frequencies for Two-Tone Phase-Plane Analysis of ADCs: Part II

A method for selecting test frequencies for two-tone phase-plane modeling of ADCs is given. The results here include and generalize the results of a previous paper on the subject. The new results show how to select a good frequency pair that is near any two specified frequencies. An error analysis is given showing how close the actual test frequencies must be to their ideal values to maintain near-optimal phase-plane coverage.