Interpolation algorithms in calculating the frame-to-frame difference for detecting moving point objects

Types of interpolation in calculating the frame-to-frame difference for decreasing the influence of the stationary background when detecting point objects are compared. The comparison is done for an observation system with a photodetector array and an oscillating axis. Methods of interpolation in the presence of a fractional shift (below the photodetector array step) are considered. Computational experiments estimating the efficiency of the methods upon detecting point objects were carried out.     

计算空间点到细分曲面有符号最近距离的方法

针对在海量细分曲面数据中计算空间点到细分曲面有符号最近距离效率较低的问题,创建一个新的细分曲面数据结构,实现细分曲面的分片表示,进而采用分治策略控制计算规模.利用细分曲面面片网格拓扑结构特性,结合多分辨率采样技术,以空间点和细分曲面极限网格顶点的最近距离作为择优指标,在细分曲面面片中搜索距离空间点最近的顶点.以最近顶点的位置和法向建立参数直线方程,以此为基础,进行最近距离的误差分析和符号判断.结合局部细分技术,提高最近距离的计算精度.基于Catmull-Clark细分模式,通过实例验证了算法的可行性和有效性.与常规方法相比,该算法计算效率高、精度可控,算法原理适用于多种细分模式.     

相序检测的极速算法

醉提出了一种相序检测的新算法，该算法运算极快，使相序检测的速度提高了1000至10000倍，可广泛运用于数字化检测之中。     

数字影像输出设备色域边界的插值计算方法

提出了一种数字影像输出设备色域边界的插值计算方法,并对其精度进行了实验分析。基于CIELAB色空间中色域的连通性和三角形插值技术,该方法直接在CIELAB L*a*b*坐标中进行插值计算,得到有规律变化的色域边界点。对3个不同类型的输出设备进行了精度分析,采用386个采样点确定色域边界,296个检验点的色度值与实际输出色度值CIELAB色差ΔE_ab的平均值/最大值分别为2.31/6.93、2.03/6.70和0.40/2.11,接近于各自设备机械稳定性引起的色差。此外,将色域表面映射为色域球,在色域球上进行插值三角形的预查找,使得插值三角形的确定时间由2.5 min缩短到10 s,降低了15倍。     

计算点到曲面最短距离的网格法

为提高最短距离计算的精度、效率和稳定性,提出了一种计算点到曲面最短距离的网格法。该方法首先利用曲面上给定的一点作为初始点,以该点为中心按给定步长将曲面划分为四个网格区域;然后分别计算空间点与初始点以及四个网格中心的距离,选取其中最小的距离作为最短距离,并得到相应网格中心;最后以该中心作为初始点,步长减半,重复以上步骤,从而获得满足一定精度的最短距离。分别以两个复杂曲面为计算实例,通过对所提方法与其他方法的计算结果进行比较,验证了该方法的有效性。     

轻便型货物列车超载偏载检测装置的研制

本文介绍研制成功的轻便型超偏载检测装置的背景、方法、设计原理、特点以及运用等,从实际运用的情况说明该装置具有轻便、快速、准确、可移动、操作简便、运行可靠等特点,在技术上具有创新,为确保铁路运输安全提供了一种装备和方法。     

复杂网络中的完全子图搜索算法研究

现实生活中,许多实际网络中通常包含由若干结点组成的完全子图,一些实际网络甚至是由一些完全子图通过公共节点链接而成的,如何搜索这类网络中的完全子图,是一件很有意义的事情.提出了一种搜索这类特殊复杂网络的完全子图的算法,编制了实现算法的程序,将算法程序应用于机械制造中的产品零部件关系网、中药方剂网等实际的复杂网络,取得了良好的效果.为深入研究这一类型的复杂网络提供了有力的工具.     

Algorithm for calculating torque base in vehicle traction control system

Existing research on the traction control system(TCS) mainly focuses on control methods, such as the PID control, fuzzy logic control, etc, aiming at achieving an ideal slip rate of the drive wheel over long control periods. The initial output of the TCS (referred to as the torque base in this paper), which has a great impact on the driving performance of the vehicle in early cycles, remains to be investigated. In order to improve the control performance of the TCS in the first several cycles, an algorithm is proposed to determine the torque base. First, torque bases are calculated by two different methods, one based on states judgment and the other based on the vehicle dynamics. The confidence level of the torque base calculated based on the vehicle dynamics is also obtained. The final torque base is then determined based on the two torque bases and the confidence level. Hardware-in-the-loop(HIL) simulation and vehicle tests emulating sudden start on low friction roads have been conducted to verify the proposed algorithm. The control performance of a PID-controlled TCS with and without the proposed torque base algorithm is compared, showing that the proposed algorithm improves the performance of the TCS over the first several cycles and enhances about 5% vehicle speed by contrast. The proposed research provides a more proper initial value for TCS control, and improves the performance of the first several control cycles of the TCS.     

基于ARINC429总线的便携式分析仪

针对现代机载电子设备维修查障时专用PC机板卡价格昂贵、操作携带不便等问题,设计了一种基于ARINC429航空数据总线的便携式分析仪.提出了双单片机结构的设计方案,在分析ARINC429总线规范的基础上,采用总线协议芯片HS-3282.配合自设计的429电平驱动电路,完成了ARINC429总线数据收发电路的设计.实验表明:分析仪可正确接收、发送总线数据.在设备维护、查障时通过分析仪与机载电子设备进行点对点的数据收发,能快速锁定故障设备,为飞机日常维护及故障排查提供了一种便捷的辅助手段.     

声自导鱼雷发现概率统计计算新思路

为了研究声自导鱼雷发现概率的正确解析计算模型,对统计计算模型进行全面的分析讨论。基于鱼雷攻击正常流程建立了一类发现概率统计计算模型(称为绝对运动模型);基于随机相对性,建立了另一类发现概率统计计算模型(称为相对运动模型)。利用灵敏度分析的方法建立了一种提前角误差均方根解析计算模型,基于此提出了一种计算量大幅减小的发现概率统计计算模型(称为部分解析统计计算模型)。仿真计算表明,提出的几种统计计算模型的结果一致,为研究正确的声自导鱼雷发现概率解析计算模型打下了基础。     

用于增材制造的点云直接分层算法

针对三维点云分层问题,将连续层片构造过程解释为对运动曲线的追踪,提出一种非监督神经网络用于从散乱点中增量式重构各层曲线.首先用分层平面对点云重采样得到二维样本点,然后逐个输入网络,使其动态增长、删除、移动、改变连接,从而抽取样本的局部主成分和拓扑结构.网络在当前层学习收敛后,其结构表达了一组多义线,该组多义线同时作为下...     

三支承车床主轴的刚度及参数优化

对三支承车床主轴从辅助支承发生作用的条件出发,假设3个支承在载荷作用下的变形呈线性关系,由此对辅助支承约束力求解,从而将超静定问题转化为静定问题,得到了主轴端部柔度(刚度的倒数)计算公式,然后根据主轴部件设计的需要,采用遗传算法对主支承跨距、辅助支承跨距和传动力作用位置等参数进行综合优化,对三支承结构的机床主轴设计有一定的参考意义。     

轴承检测仪器测点的使用方法及注意事项

轴承在制造过程中,需对其精度进行检测。检测仪器上的测点材料及使用方法如果选取不当,就会对被加工轴承表面质量造成影响。论述了测点材料的选取方法、测点的使用方法及注意事项,对保证轴承质量起着非常重要的作用。     

Pre- and post-thaw assessment of intracellular ice formation

Intracellular ice formation (IIF) refers to the formation of ice crystals within cells during rapid freezing. To develop an understanding of the means by which intracellular ice forms and the mechanisms by which it damages cells and tissues requires techniques that combine real‐time assessment of ice nucleation and ice crystal growth with detailed assessments of cell structure and function. Intracellular ice formation has been detected in live samples using light scattering, freeze substitution and fluorescent detection. In this study we develop a method to correlate IIF with post‐thaw structural analyses by combining low temperature microscopy and freeze substitution. V79‐4 hamster fibroblasts were frozen on a low temperature microscope at various temperatures, IIF was visualized using the nucleic acid‐specific fluorophore SYTO 13?, then the samples were fixed (10% formaldehyde, 85% ethanol, 5% acetic acid) while still frozen. The monolayers were then thawed and stained with routine histological stains haematoxylin and eosin and assessed. Fixation allowed for the post‐thaw assessment of IIF and for subsequent histological processing to examine in detail the structural consequences of IIF. The post‐thaw identification of cells that form intracellular ice during freezing is a significant improvement to current methods used in low temperature biology.     

Fiber optic sensing technology for detecting gas hydrate formation and decomposition

A fiber optic-based distributed sensing system (DSS) has been integrated with a large volume (72 l) pressure vessel providing high spatial resolution, time-resolved, 3D measurement of hybrid temperature-strain (TS) values within experimental sediment-gas hydrate systems. Areas of gas hydrate formation (exothermic) and decomposition (endothermic) can be characterized through this proxy by time series analysis of discrete data points collected along the length of optical fibers placed within a sediment system. Data are visualized as an animation of TS values along the length of each fiber over time. Experiments conducted in the Seafloor Process Simulator at Oak Ridge National Laboratory clearly indicate hydrate formation and dissociation events at expected pressure-temperature conditions given the thermodynamics of the CH(4)-H(2)O system. The high spatial resolution achieved with fiber optic technology makes the DSS a useful tool for visualizing time-resolved formation and dissociation of gas hydrates in large-scale sediment experiments.     

Study of the conditions necessary for propane-jet freezing of fresh biological tissues without detectable ice formation

The performance of a commercial double-propane-jet freezer (Balzers QFD 101) has been assessed, for rapid freezing of fresh tissues in freeze-etch work. Samples of diaphragm muscle and intestinal villi were frozen between copper sheets, with a spacer to give 20–30μm thickness of tissue. Fracture cuts were made with the Balzers BAF 400 freeze-etch microtome within 5–10μm of a freezing face (i.e. a tissue face in contact with the copper sheets of the frozen sandwich). After some modifications to the QFD 101, replicas showing no evidence of ice were obtained of muscle cells, although for intestinal epithelial cells some evidence of ice formation was found. Infiltration with 5% glycerol or dimethylsulphoxide improves the depth of good freezing. Results and problems arising from such infiltration are briefly discussed.     

Construction of a multichannel filter for detecting point targets in the image formed by a matrix photodetector

A new approach is proposed to construct a multichannel filter for detecting small-size targets in images recorded by a matrix photodetector. For estimating the pulse response of each channel of the filter, the set of experimentally obtained images of targets having different locations with respect to photodetector cells is divided into several subsets, which are used as reference elements in calculating the pulse response of the filter. Experimental data are presented, which demonstrate appreciable reduction of the probability of missing the targets in images subjected to processing with a filter constructed by the proposed method.     

A time-of-flight mass spectrometer for detecting a point of air leakage from a spacecraft module

The possibility of using a time-of-flight mass spectrometer for determining a point of air leakage from a spacecraft module is discussed. A procedure for carrying out ground experiments in a vacuum chamber is proposed for artificial simulation of the composition of the intrinsic external atmosphere of the spaccraft. The described mass spectrometer is capable of detecting leakages of small-concentration gas flows with a high level of confidence.