基于逻辑神经网络的图象处理方法

阐述了基于逻辑神经网络的图象平滑、压缩编码方法。这些方法的基本思想是：以逻辑神经网络为窗口,选择对某种图象变换敏感的模式训练窗口。当窗口对图象扫描时,窗口在图象的各位置输出响应,通过对这些响应的简单运算,实现所希望的处理。除了理论分析外,文中还给出了各种方法的典型试验结果。     

从云纹数字图象直接建立应变场图象的新方法

 本文提出一种从云纹数字图象直接建立数字应变场图象的新方法。数字应变场图象直接用图象灰度表示应变大小。此方法不但得到定量的、直观形象的应变场图象,且方法简单,实用,满足工程精度要求。     

某型机械数字视频记录仪的设计与实现

介绍了一种用数字技术实现飞机视频记录的方法 ,并就某型飞机的技术要求设计和实现了机载视频记录系统。文中就数字压缩算法、工程实现中的技术要点和难点做了详细介绍。     

三维非定常流场显示与测量

给出80°三角翼和Λ机翼模型低速三维非定常流场显示和测量结果,包括大迎角和大滚转角时前缘涡跳动频率及相应模型的抖动频率测量,模型作大幅度振动时流动图象的相位平均测量,以及由平行6片光经三维重建得到空间流动图象.测量结果表明,获得了在大迎角下模型抖动是由前缘涡的非定常跳动引起的这一新的流动机理.作为一种新的测量技术和新概念,模型大幅度振动时流动图象的相位平均测量,提供了研究非定常涡特性和定量确定涡核位置的有效手段.类似核磁共振(MRI)图象处理,由平行6片光流动显示经三维重建得到空间图象,对于分析涡的破碎、绕合、再附等现象是流动显示技术的新进步.     

三维随机图象模型及其空间关系

为了用随机的方法对三维图象进行处理,在二维 Markov场图象模型的基础上,建立了三维 Markov场图象模型。把定义在平面域上随机场的邻域系、集簇和势函数等概念推广到三维空间域,给出了三维邻域系、集簇的空间分布规律和势函数的具体表达式,解释了其空间关系和概率分布,从理论上解决了三维建模的问题,并为三维图象的计算机处理,提供了一种可以实际进行操作的随机方法。     

金属图象分割的研究

结合金属图象的特点,利用传统阚值分割技术和基于最大熵原则的图象分割技术对金属图象分割进行了分析;并根据金属图象分析要求,提出了先二值化金属图象再进行边缘提取的方法.对比实验结果表明,基于最大熵原则的图象分割技术可以获得较好的分割效果,所提出的方法能够获得连续闭合的晶粒边缘,为下一步的金属图象分析提供了可靠的依据.     

面向GPU快速处理的地面材质数据压缩方法 陆巍巍 1,徐涛2,徐珂文 1

为解决雷达图像仿真中海量地面材质数据的存储和加载问题,采用基于自适应最大行程长度编码和修正 偶对的压缩算法进行材质数据的压缩,从而有效地减少了数据的存储量,消除数据传输的瓶颈,提高了数据传输的 吞吐能力。压缩算法面向 GPU快速处理,得到压缩数据适用于 GPU进行快速解压。     

面向GPU快速处理的地面材质数据压缩方法

为解决雷达图像仿真中海量地面材质数据的存储和加载问题,采用基于自适应最大行程长度编码和修正偶对的压缩算法进行材质数据的压缩,从而有效地减少了数据的存储量,消除数据传输的瓶颈,提高了数据传输的吞吐能力。压缩算法面向GPU快速处理,得到压缩数据适用于GPU进行快速解压。     

扫描跟踪和图象跟踪之间的协调控制

扫描跟踪和图象跟踪方式之间的协调控制系统设计者提出了一些重要的问题。扫描跟踪用于点目标，图象跟踪用于大面积目标；在任何给定条件下，有时两种方法都可能用到。必须找到协调控制的一个最佳点。目标还可能在扫描跟踪和图象跟踪最佳的状态之间变化。当用一种方式丢失目标后，用另一种方式再次捕获目标又是另一个必须论述的问题。两种方式的局限性是需要考虑的：采用二维空间算法点点目标探测取决于目标和滤波器这两者的外形尺寸大小。图象跟踪的实现主要取决于目标的大小和形状。本文将论述采用典型的扫描跟踪探测点目标的探测算法，简要地介绍一种典型的图象跟踪器并给出几种不同情况下获得的结果。     

一种测定超高燃速推进剂孔隙结构的方法

应用微机显微图象处理系统建立了超高燃速推进剂（ＵＨＢＲ）截面微孔结构的测试方法。自行组装并调试了ＷＸＴ－８８型微机显微图象测定仪，研究了灰度域值、光照条件、采样方式等对测试精度的影响及其控制方法。通过对ＰＶＣ－ＵＨＢＲ的大量测试工作，表明该方法可用于测定微孔结构的参数，系统测试误差可控制在３％以内。采取两端截面，多幅图象采集，统计平均值的办法，可以反映ＰＶＣ－ＵＨＢＲ的微孔结构状况。     

Firewire: standard computer industry interconnect for test & measurement

Do you know what Firewire is? If not, you soon will, IEEE 1394, or Firewire, is an up-and-coming electronics industry standard that will soon be in wide use for interconnecting a massive variety of electronic equipment. It will be used for connecting CD-ROMs and scanners to computers, and it will be used for connecting VCRs, DVDs and satellite dishes to digital televisions. How does this affect Test & Measurement? This paper discusses Firewire, along with it's lower-end companion, USE, and how they can and will be utilized in T&M applications to replace T&M specific technologies, such as IEEE 488, and MXI. The advantages-and disadvantages-of these new technologies are discussed along with what the Test & Measurement industry should do to support these new technologies.     

航空橡胶密封件力学与密封性能检测技术

介绍了航空橡胶密封件的力学、泄漏、损伤、接触变形等特性的无损检测技术及应用情况。其中,橡胶密封件泄漏压差测量方法,用于获得不同压差下的气体泄漏率;橡胶密封件接触应力超声检测技术,实现了橡胶密封接触应力的准确测量;橡胶密封件损伤与泄漏的红外热成像测试技术,可以得到泄漏点的定位与泄漏量的精确测量;橡胶密封件接触变形数字图像相关技术,获得了织物接触界面变形场与应力场的演化规律等。同时,对航空橡胶密封件的非接触测量技术进行了展望。     

移动工业机器人在飞机装配生产线中的应用研究

在总结移动工业机器人在飞机装配生产线等航空制造场景典型应用的基础上,重点分析了移动工业机器人多传感器融合的同步定位和建图、移动机器人导航控制、机械臂精度控制和数字化测量等关键技术,并对未来航空领域移动机器人的人机协作、多传感器数据融合、智能规划与决策、数字孪生体系等发展趋势进行了阐述。     

Data fusion for ground moving target tracking

The aim of ground surveillance is the large scale, continuous and near real time determination of a dynamical ground picture. This task comprises detection and tracking of moving single targets and convoys, mobile weapon systems, and military equipment. The sensors of choice are airborne Ground Moving Target Indicator (GMTI) radar and synthetic aperture radar (SAR). As ground target tracking often suffers from dense target situations, high clutter, and low visibility, the integration and fusion of external background information is essential for providing precise and continuous tracks. We present Multi Hypotheses techniques for tracking several targets in complex ground situations with clutter. Methods to incorporate topographic information, in particular digital road maps, are described and demonstrated.     

ARMA Time Series Modeling: an Effective Method

The ability to generate rational models of time series plays an important role in such applications as adaptive filtering, spectral estimation, digital control, array processing, and forecasting. A method for effecting an autoregressive moving average (ARMA) model estimate is presented which possesses a number of admirable properties: 1) it has an elegant algebraic structure, 2) its modeling performance in spectral estimation applications has been empirically found to typically exceed that of such contemporary techniques as the periodogram, the Burg method, and the Box-Jenkins method on a variety of problems, 3) it is implementable by computationally efficient algorithms, and 4) it is based on pseudomaximum likelihood concepts. Taken in combination, these properties mark this method as being an effective tool in challenging applications requiring high modeling performance in a real time setting.     

CFD技术在航空工程领域的应用、挑战与发展

计算流体力学(CFD)技术在航空工程领域发挥着重要作用。总结了CFD技术在航空工程领域中的应用,系统阐述了气动设计、气动弹性、气动噪声、数字化飞行等多学科耦合计算领域对CFD技术的需求,结合实际工程应用分析了CFD技术面临的主要挑战。总结了近年来CFD技术在流动分离、边界层转捩、高精度方法和运动网格技术等领域取得的研究成果以及在气动特性评估、流动机理分析、气动设计、气动弹性、气动噪声等工程领域中的应用。进一步展望了CFD数值模拟未来的几个关键技术以及应用前景。     

Low-cost technology for multimode radar

A flexible test bed radar architecture is described which includes an integrated RF electronics package that can support multiple radar applications, including surveillance, fire control, target acquisition, and tracking. This type of architecture can significantly reduce the cost, power, size, and weight of electronics on future weapon delivery platforms. The Army Research Laboratory (ARL) is developing technology to support multimode radar requirements. These requirements include the detection and location of moving or stationary low radar cross section targets in heavy ground clutter and the classification and/or recognition of these targets. We address these requirements with commercial-off-the-shelf (COTS) products and the integration of several enabling technologies. The test bed radar includes a direct digital synthesizer (DDS) for frequency-diverse waveform generation, a flexible wideband transceiver for bandwidth extension and frequency translation, and an open architecture signal processor with embedded wideband analog-to-digital converters for real-time acquisition and processing. Efficient signal processing algorithms have been developed to demonstrate multimode radar capability. This paper discusses the various subassemblies, algorithm efficiency, and field experiment results     

飞机结构数字孪生关键建模仿真技术

飞机结构安全性设计思想经历了从静强度设计、安全寿命设计、损伤容限与耐久性设计到单机追踪的演变,未来有进一步向结构数字孪生的方向发展的趋势。飞机结构数字孪生是数字线程驱动的,多学科、多物理、多尺度、多保真度、多概率的模拟仿真系统,采用在线传感器监测、离线地面检查、飞机运行历史等多源数据,反映并预测对应飞机结构实体在全寿命周期内的行为和性能,有望革新现有的飞机结构使用和维护模式。面向疲劳寿命管理,提出飞机结构数字孪生的5项关键建模仿真技术,分别是载荷和损伤的数据获取技术、多尺度建模和力学分析技术、含裂纹复杂结构的精确高效仿真技术、基于降阶的数字孪生高效建模技术和考虑不确定性与多源异构数据的剩余寿命评估技术,并详细探讨这五项关键技术的研究现状与发展方向,为飞机结构数字孪生的系统研究与工程应用提供参考。     

提高图像清晰度二维数字滤波器的设计

互补高、低通滤波方案是兼容发展高清晰度电视诸多方案的一种。在互补高、低通滤波方案中滤波器制作的好坏直接关系到恢复图像的质量。本文着重介绍互补高、低通滤波方案中二维高、低通滤波器的设计方法及设计结果。     

The chemical composition of B-supergiant atmospheres

We present new estimates of He/H and CNO abundance ratios in the atmospheres of a selection of B2 supergiants which imply that the C/N ratio in the most luminous Ia stars is close to its equilibrium value. The is also some evidence for more moderate CN abundance anomalies in the B2Ib and B2II supergiants. These results, together with other recent work, imply that the effects of the CNO bi-cycle on the composition of B-supergiant atmospheres are most severe for the more luminous and massive stars. Furthermore, studies of LMC B-supergiants indicate that a small fraction of these very luminous stars are nitrogen weak. This picture is qualitatively consistent with theoretical predictions whenever massive stars perform blue loops in the HR diagram, returning from a red supergiant phase to become core helium burning blue supergiants with atmospheres contaminated by nuclear processed material.