一种新的雷达目标航迹模拟方法

雷达目标模拟航迹产生的数据是进行各种雷达数据处理研究的前提。文章提出了一种基于状态方程的航迹模拟方法，该方法是利用目标运动的状态方程及最优控制理论来进行航迹模拟，最大的优点在于产生的数据符合目标运动的特性，更真实的接近空中目标实际运动的轨迹。仿真实验结果表明了该算法的有效性。     

战略空中目标经典航迹匹配模型研究

针对战略空中目标经典航迹匹配问题,提出一种多属性加权关联匹配模型,重点解决了热点区域战略空中目标经典航迹提取及实时航迹的关联匹配。针对热点区域经典航迹库生成,应用凸包Graham’s Scan算法对航迹群进行聚类分析,提取经典航迹凸包并生成经典航迹库;针对实时航迹的关联匹配,提出一种多属性加权关联匹配模型,通过仿真试验确定位置、速度、航向等属性的最优权重。该模型已应用于某信息系统,有效提取了经典航迹活动规律并可以实时匹配经典航迹,同时,为空中战略态势研判提供了有力支撑。     

对空中飞行目标的动态仿真及飞行图像的处理

在高炮射击和雷达跟踪的大型半实物仿真系统中，模拟空中目标的飞行航迹和对飞行图像的处理是非常关键的环节。在VisualC＋＋6．0开发环境下利用三维图形函数库OpenGL工具来模拟飞机的飞行航迹，并对航路图像进行格式转换处理，用以满足仿真系统所要求的图像格式，这对于空中目标的仿真具有一定的参考价值。     

信息融合理论在某指控系统中的应用

基于实际工程背景 ,提出了对某型防空指挥系统空中运动目标航迹进行信息融合的有关理论和方法 ,此方法在数学仿真中取得了良好的效果     

刚体目标大机动飞行的仿真研究

分析典型航迹的特征规律,根据多段航迹组合生成航迹的思想,运用3种基本的目标状态方程模拟刚体目标大机动飞行的三维航迹。针对模型切换时的航迹平滑问题,提出基于最小二乘拟合的航迹仿真方法,以准确描述刚体目标的运动规律。修正基于航迹的刚体目标姿态角计算方法,避免模型切换时的姿态角振荡现象,便于相关应用的实现。     

基于Google Earth的三维航迹监视及六自由度飞行仿真

提出了一种利用Google Earth二次开发能力实现飞机三维航迹监视和六自由度飞行仿真的新方法.使用KML语言描述飞机三维航迹和飞行姿态,通过Google Earth提供的可扩展接口引入飞机监视数据得到Google Earth上的飞机实时三维航迹及六自由度飞行仿真.系统采用B/S架构,客户端采用Google Earth 浏览器,全部开发都在服务器端.提出了一种用飞机前后两个位置点空间连线矢量提取飞行姿态算法.用这种方式得到三维航迹简单直观,既可以用于三维航迹研究分析、实时航迹监视、六自由度飞行仿真,还可以作为一种新的航班动态查询工具.     

声传感器阵列的实验研究

海洋中对目标的判决主要依靠于水听器阵列对水声信号的检测。为了对比声压阵与矢量阵对信号的检测能力,首先计算机仿真了声压阵和矢量阵的增益及其对目标方位的估计,而后加以实验验证。实验结果表明,矢量阵的增益高于声压阵,且其克服了声压阵左、右舷模糊的问题,能精确的对目标方位进行估计并完成对水下运动目标的航迹跟踪,从而验证了矢量阵的优越性。     

基于矢量传感器的空中脱靶量测量方法研究

针对现有声学空中脱靶量测量方法,无法实现三维定位的现状,提出引入矢量传感器技术的新思路。设计了一种基于矢量声学传感器的布阵方案,采用声压、振速互谱实现了目标的到达方向﹙DOA﹚估计,并利用概率法实现了多基阵的目标三维定位。通过仿真实验表明:该方法可以解决声学脱靶量测量空间定位技术难题,定位精度满足要求。     

空中机动目标三维视景仿真系统研究

本文采用Multigen Creator/Vega三维视景仿真机制,对空中机动目标三维视景仿真系统进行场景建模和场景驱动.从模型的几何结构和表面纹理着手,优化模型数据库;利用Vega路径定义模块规划空中机动目标飞行路径,合理设置每个路径控制点的姿态和速度,模拟加减速、侧翻、跃升、俯冲等一系列飞行动作;选取静态视点定位方式;并为场景添加无限光源和链式云,增加场景的生动性.仿真结果表明该系统能够充分的表达空中机动目标的运动特点,具有很好的实用价值.     

基于矢量传感器的空中脱靶量测量方法研究

针对现有声学空中脱靶量测量方法,无法实现三维定位的现状,提出引入矢量传感器技术的新思路.设计了一种基于矢量声学传感器的布阵方案,采用声压、振速互谱实现了目标的到达方向(DOA)估计,并利用概率法实现了多基阵的目标三维定位.通过仿真实验表明:该方法可以解决声学脱靶量测量空间定位技术难题,定位精度满足要求.     

基于OpenGL的数控雕刻机加工仿真系统的研究

本文介绍了一种基于OpenGL的数控雕刻机加工仿真系统.它的实现采用了Visual C＋＋6.0开发工具,以及用OpenGL开发的雕刻机三维加工仿真软件.本文还重点介绍了刀具加工轨迹的建模及三维动画的实现.     

Development of Unmanned Aerial Vehicle (UAV) system with waypoint tracking and vision-based reconnaissance

This paper introduces the developed UAV system for low cost operation and an EOS (Electro Optical System) laboratory. This paper highlights an autonomous navigation system based on microcontrollers that can track a target using images, take three-dimensional measurements of the target, and acquire high quality images. The hardware system and an algorithm for the EOS verify the performance of the image tracking system and 3-D measurement of the target’s position. 3-D position estimations for the target are solved using the mathematical relationship between the UAV and target. Although an on-board EOS can make errors in 3-D measurement, the proposed approach shows improved accuracy and confidence for 3-D target tracking using a postprocessing method.     

基于颜色-空间二维直方图的目标跟踪技术研究

由于颜色直方图只考虑了目标颜色的统计信息,忽略了目标颜色的空间信息,使得在模板匹配过程中容易收敛到其他位置,从而导致目标丢失。针对这一缺点,提出了一种基于颜色-空间二维直方图的目标跟踪技术,在建立目标模板的过程中融入了目标颜色的空间信息。实验结果表明,与传统的基于颜色直方图的Mean-shift算法相比,基于颜色-空间二维直方图的目标跟踪技术能更准确的对目标进行跟踪,提高了目标跟踪的鲁棒性。     

Theories and algorithms for 3-D root canal model construction

This paper presents theories and algorithms for 3-D root canal model construction from 2-D X-ray images in a clinically practical way: (1) the geometrical rectification algorithm for correcting distorted 2-D X-ray images, (2) the transformation algorithms from 2-D X-ray image coordinate system to unified 3-D reference coordinate system, (3) the merging algorithms and theory for obtaining spatial root canal centerline by intersecting two surfaces with assumed parallel projection, and (4) the elliptical theory for exploring the root canal cross-sectional geometry. Using those theories and algorithms, three 3-D computer models constructed from teeth samples are presented to show the feasibility. The internal geometrical structure provided by 3-D computer graphics enables the clinician and the patient to comprehend root canal morphology efficiently, and the destructive access preparation before a clinician's inspection may be avoided during clinic practice.     

Experimental research on resist filling behavior in microimprint lithography by using defocusing digital particle image velocimetry

The resist filling behavior is crucial to the quality of the final imprinted patterns in microimprint lithography. To achieve the microscale velocity field of resist, a 3-D defocusing digital particle image velocimetry (DDPIV) system was established. The spatial coordinates of 500 nm fluorescent tracer particles were inferred from their DDPIV images generated by a mask with three apertures forming an equilateral triangle. Time-resolved 3-D particle field inside the resist was obtained with the spatial coordinates of particles. Particle tracking velocimetry was utilized to derive the velocity field from the particle spatial position in the imprinting sequence. Velocity history of particles along the extracted track was described. The results showed that the maximum velocity of the resist was always located in the region between the mold corner and the supporting substrate; meanwhile, the velocity component of the resist in the vertical direction is approximate to zero. The volume transfer characteristics of resist was illustrated from the view of particle field and velocity field, which will help reveal the resist filling mechanism and provide useful guidance for the mold structure optimization.     

基于3R及大气折射修正的目标高度定位精度研究

雷达测得的距离信息不需要转化,可直接用于目标定位,具有较高的精度,但高空中的大气折射会给测距带来干扰,降低目标的定位精度。本文利用3R定位模型确定出目标的理想空间位置;与考虑大气折射影响后进行改进的等效地球半径模型相结合,进行海拔高度的求解;将三站计算的海拔高度进行不同的加权处理,得出目标处于不同高度下的大气折射修正值。仿真结果表明,该方法改善和提高了系统对目标的定位精度,进一步增强了系统的作战能力。     

Fusion of range camera and photogrammetry: a systematic procedure for improving 3-D models metric accuracy

The generation of three-dimensional (3-D) digital models produced by optical technologies in some cases involves metric errors. This happens when small high-resolution 3-D images are assembled together in order to model a large object. In some applications, as for example 3-D modeling of Cultural Heritage, the problem of metric accuracy is a major issue and no methods are currently available for enhancing it. The authors present a procedure by which the metric reliability of the 3-D model, obtained through iterative alignments of many range maps, can be guaranteed to a known acceptable level. The goal is the integration of the 3-D range camera system with a close range digital photogrammetry technique. The basic idea is to generate a global coordinate system determined by the digital photogrammetric procedure, measuring the spatial coordinates of optical targets placed around the object to be modeled. Such coordinates, set as reference points, allow the proper rigid motion of few key range maps, including a portion of the targets, in the global reference system defined by photogrammetry. The other 3-D images are normally aligned around these locked images with usual iterative algorithms. Experimental results on an anthropomorphic test object, comparing the conventional and the proposed alignment method, are finally reported.     

单目平行线约束下的空间点坐标恢复

提出一种从单目像机拍摄的二维投影图像中恢复空间点三维坐标的简化算法.假定摄像机与空间中的一对平行线的位置关系已知,同时摄像机坐标系下平行线所在平面中的任意空间点在像平面中的投影也已知,通过射影几何可得图像坐标到目标点三维空间坐标的转换系数,即坐标转换因数,从而估计出三维空间点的坐标.实验中通过对人体行走轨迹进行估计来测试算法性能,结果表明算法简单有效,计算开销小.     

Three-dimensional X-band SAR imaging of a small conifer tree

High spatial resolution 3-D SAR imagery was recorded by the UK's Natural Environment Research Council GB-SAR Microwave Measurement Facility at the University of Sheffield. X-band VV polarisation measurements were made using a near-field monostatic imaging system inside an anechoic chamber. The measurement process employs vector network analyser techniques to sample backscattered signals over a 2-D aperture, allowing a 3-D reconstruction of a target. This technique is used to provide a detailed 3-D map of the spatial scattering behaviour of a small Colorado Blue Spruce tree (Picea pungens glauca). The images produced are at a sufficiently high spatial resolution (～5cm) that individual plant components can be discerned. An ability to select any volume pixel from within the target allows features in the microwave reconstruction to be readily associated with structures in the tree. The scattering behaviour associated with the uppermost set of branches shows it to be dominated by scattering from the branch tips.     

连续杆战斗部仿真模型研究

假设在爆炸过程中连续杆战斗部杆环向四周均匀张开，且杆条保持刚直、不变形；杆环断开前将单一杆条的运动分解为质心的平动和杆条绕质心的转动，达到扩张半径时各杆条同时断开；推导了战斗部静态爆炸时杆条中心和交义点的参数方程；根据导弹飞行速度建立了战斗部动态飞散模型；在目标坐标系中建立了杆环相对飞散模型；利用杆条中心和交叉点的参数方程，可方便地推导链环各点的参数方程；在目标坐标系中，战斗部相对飞散模型联立目标离散单元的平面方程可计算损伤点，依次连线得出损伤轨迹。