运动模糊图像的维纳滤波复原研究

根据运动造成图像模糊的特点详细分析了匀速直线运动模糊图像的退化模型和恢复模型,提出直接在运动方向上建立点扩展函数的算法,并利用改进的霍夫变换检测点扩散参数,再利用二次维纳滤波的方法复原图像。通过实验表明在图像先验条件的要求没有增加的情况下,该方法提高图了像复原的抗噪性和稳定性,并且有效的保持图像细节。     

Link-16数据链抗干扰性能分析与仿真

在部队通信服务问题的研究中,数据链仿真是数据链武器装备论证的重要研究内容和方法,对军队数据链建设具有重要意义.以美军现役战术数据链Link-16为背景,比较分析了数据链系统的四类信息传输方式,为提高抗干扰性能,介绍了主要的抗干扰技术.利用Simulink软件对数据链系统建立了链路仿真平台,重点构建了直序扩频模块和跳频模块,对在加性高斯白噪声和莱斯衰落影响下的信号传输进行了仿真并进行了抗干扰性能分析.通过仿真与分析可以看出,RS编码、直序扩频、跳频等技术保证了Link-16数据链的高抗干扰性能,使其满足军用通信要求.     

基于Gibbs分布的盲图像修复

针对盲图像去卷积问题,首先建立了一个基于Gibbs分布加权算法模型,然后讨论了关于能量泛函极小解的存在性,最后导出了相应的热流。在计算机模拟中,除了某些限制条件外,即使对于点扩散函数和原始的真实图像没有更多精确的信息,此算法也运行得很好。为了进一步观察此算法的实效性,与全变差盲去卷积模型的实验结果进行了比较。     

长波红外图像雨雾效果仿真

图像仿真有时需要得到相同场景不同天气下的图像,为特定的图像分析提供数据.针对长波红外图像雨雾效果的仿真,分析了雨雾天气下大气介质对长波红外(8-12μm)成像的影响,提出了一种雨雾效果仿真方法.用大气点扩展函数来表示雨雾天气对红外图像质量的影响,运用蒙特卡罗方法仿真红外辐射在雨雾中的传输过程,分别得到了雨天和雾天的大气点扩展函数.利用雨雾天气下的大气点扩展函数对场景的红外图像作变换得到了有雨雾效果的红外图像.最后给出的仿真结果基本达到了实际雨雾天气的效果.     

Up in smoke: I. Smoke-derived germination cues for postfire annual,Nicotiana attenuata torr. Ex. Watson

Some postfire annuals with dormant seeds use heat or chemical cues from charred wood to synchronize their germination with the postfire environment. We report that wood smoke and polar extracts of wood smoke, but not the ash of burned wood, contain potent cue(s) that stimulate germination in the postfire annual plant,Nicotiana attenuata. We examined the responses of seeds from six populations of plants from southwest Utah to extracts of smoke and found the proportion of viable seeds that germinated in the presence of smoke cues to vary between populations but to be consistent between generations. With the most dormant genotypes, we examine three mechanisms by which smoke-derived chemical cues may stimulate germination (chemical scarification of the seed coat and nutritive- and signal-mediated stimulation of germination) and report that the response is consistent with the signal-mediated mechanism. The germination cue(s) found in smoke are produced by the burning of hay, hardwood branches, leaves, and, to a lesser degree, cellulose. Moreover, the cues are found in the common food condiment, liquid smoke, and we find no significant differences between brands. With a bioassay-driven fractionation of liquid smoke, we identified 71 compounds in active fractions by GC-MS and AA spectrometry. However, when these compounds were tested in pure form or in combinations that mimicked the composition of active fractions over a range of concentrations, they failed to stimulate germination to the same degree that smoke fractions did. Moreover, enzymatic oxidation of some of these compounds also failed to stimulate germination. In addition, we tested 43 additional compounds also reported from smoke, 85 compounds that were structurally similar to those reported from smoke and 34 compounds reported to influence germination in other species. Of the 233 compounds tested, 16 proved to inhibit germination at the concentrations tested, and none reproduced the activity of wood smoke. By thermally desorbing smoke produced by cellulose combustions that was trapped on Chromosorb 101, we demonstrate that the cue is desorbed between 125 and 150°C. We estimate that the germination cues are active at concentrations of less than 1 pg/seed and, due to their chromatographic behavior, infer that a number of different chemical structures are active. In separate experiments, we demonstrate that cues remain active for at least 53 days in soil under greenhouse conditions and that the application of aqucous extracts of smoke to soil containing seeds results in dramatic increases in germination of artificial seed banks. Hence, although the chemical nature of the germination cue remains elusive, the stability of the germination cues, their water-solubility, and their activity in low concentrations suggest that these cues could serve as powerful tools for the examination of dormant seed banks and the selective factors thought to be important in the evolution of postfire plant communities.     

FSNet: 基于频率特性的烟雾图像分割网络

烟雾图像分割是对烟雾进行识别与精准定位的基础, 是火灾预警的重要手段. 针对烟雾分割时存在过分割、欠分割以及边界拟合粗糙的问题, 本文提出一种基于频率分离特性的烟雾图像分割网络. 所提出的频率分离模块将特征图中的烟雾区域分离为低频主体部分和高频边界部分, 同时基于多任务学习设计多模块权重自适应损失函数对烟雾整体、主体、边界分别监督学习, 起到细化烟雾边界和改善烟雾整体分割结果的作用; 此外, 结合可变形卷积提出改进的空洞空间金字塔池化模块以解决其信息利用率低和特征关联性差的问题. 在对比实验中, FSNet的烟雾交并比为76.55%, 比基线网络提高了4.25%. 可视化分割结果可以看出, FSNet能有效缓解过分割、欠分割, 所得烟雾边界更平滑, 烟雾图像分割的整体性能获得较大提升.     

扩频体制低轨卫星通信信号捕获与跟踪系统设计

针对扩频体制下低轨卫星信号的捕获及跟踪等系统设计实现问题,根据卫星信号模型进行了捕获及跟踪算法设计,重点对基于快速傅里叶变换的快速捕获算法、锁频环、锁相环和码跟踪环路进行了设计,并进行了工程系统实现。试验验证表明,该系统可以实现码分多址体制低轨卫星信号捕获、跟踪处理,工作性能参数满足系统需求。     

基于PSF参考模型的星敏感器单粒子效应在轨校正方法

为了提高星敏感器在遭受单粒子效应打击情况下的质心提取精度,提出了一种基于点扩散函数参考模型的在轨校正方法。通过构建星点参考模型及残差校正,该方法能有效去除单粒子噪声,校正噪声星点形态,降低星点质心定位误差。与传统去噪算法相比,该方法能在有效去噪的同时保护星点能量不被破坏。通过仿真实验验证了该算法抗单粒子效应的有效性,通过对比实验验证了该算法相比传统算法的优越性。     

轻音乐对驾驶疲劳的双向影响

目的本实验探索驾驶负荷累积与轻音乐对驾驶疲劳的影响。方法采用2(驾驶负荷累积)×2(音乐条件)×3(模拟驾驶阶段)混合设计,对32名驾驶员被试进行模拟驾驶实验,采集驾驶员驾驶速度和他们的垂直搜索广度与瞳孔直径。结果第45-60 min时,对于无驾驶负荷累积的被试,轻音乐组车速显著快于无音乐组,轻音乐组垂直搜索广度显著大于无音乐组;对于有驾驶负荷累积的被试,轻音乐组的瞳孔直径小于无音乐组(边缘显著),轻音乐组的车速慢于无音乐组。结论轻音乐对无累积疲劳的驾驶员具有唤醒作用,加快他们的车速,扩大垂直搜索广度,对驾驶绩效具有积极的影响;轻音乐对有累积疲劳的驾驶员会产生催眠作用,缩小瞳孔直径,车速减慢,对驾驶绩效具有消极的影响。     

膨胀型阻燃涂料对木材的阻燃性能

以脲醛树脂(UF)和硅丙乳液(SEA)树脂分别为基料,三聚氰胺磷酸盐(MP)-三聚氰胺(MEL)-季戊四醇(PER)为膨胀阻燃体系,制备膨胀型阻燃涂料。通过极限氧指数、热重分析、锥形量热、扫描电镜对涂料阻燃性能表征分析证明,与SEA相比,UF分解温度较低,残炭量提高了11.53%;与硅丙乳液基三聚氰胺磷酸盐涂料(SEA/MP)木材阻燃涂料相比,脲醛树脂基三聚氰胺磷酸盐涂料(UF/MP/MEL/PER)木材阻燃涂料具有良好的阻燃性能、热稳定性和抑烟性能,残炭量提高了5.05%,总放热量降低了17.0%,总烟气生成量降低了39.3%,在木材表面形成的炭层更加完整。