对2幅不同角度、不同光照条件或不同相机采集到的图像进行配准,是一项十分具有挑战性的研究。针对参考图像和待配准图像对之间存在的仿射变换问题,提出了一种灵活通用的、基于SIFT特征和角度相对距离的图像配准算法。算法充分利用了图...对2幅不同角度、不同光照条件或不同相机采集到的图像进行配准,是一项十分具有挑战性的研究。针对参考图像和待配准图像对之间存在的仿射变换问题,提出了一种灵活通用的、基于SIFT特征和角度相对距离的图像配准算法。算法充分利用了图像正确匹配特征点对之间存在的角度关系,实现了特征点之间的精确匹配。将所提算法同LLT(locally linear transforming)算法及RANSAC算法进行了对比实验,结果表明,新算法有较高的有效性和鲁棒性。而且新算法不仅适用于普通图像,在近红外与可见光图像以及遥感图像中均充分体现了良好的鲁棒性和适用性,在匹配特征点数目较少时,也具有良好的鲁棒性。展开更多
The common vibration of cable caused by rain-wind combination has been known as most typical type and a lot kind of its countermeasures has been proposed for suppressing this phenomenon. Recently, stayed-cables were a...The common vibration of cable caused by rain-wind combination has been known as most typical type and a lot kind of its countermeasures has been proposed for suppressing this phenomenon. Recently, stayed-cables were also proved that they could be excited in dry state （without rain）, which is called dry-galloping. Recently, its mechanisms have been explained by axial flow, Reynolds number and so on. To clarify the characteristics of this galloping, wind tunnel test of a cable model with various kinds of wind angle was conducted. Then, three types of countermeasure were examined to suppress dry- galloping of bridge cable. The tests confirmed that the occurrence of dry-galloping depends on relative wind attacked angles and onset reduced wind speed. Furthermore, single spiral wire, double spiral wire and circular ring were found to have high effectiveness in mitigating this galloping when those are installed properly.展开更多
文摘为了探索高频段室内无线体域网通信的可行性,对11 GHz室内无线体域网的传播特性进行了测量与研究。基于大量的测量数据,给出了11 GHz频段室内无线体域网的路径损耗、阴影效应与均方根时延扩展的统计特性。针对体对体通信时人体相对角度变化的场景,提出了一种具有相对角度影响的路径损耗模型,该模型利用了与身体角度相关的路径损耗指数、浮动截距以及身体角度因子修正相对角度变化引入的路径损耗。为了验证模型的适用性,对比分析了在小型空教室和大型会议室两种不同场景下相对角度变化对信道传播特性的影响。研究结果表明:在收发端距离固定的情况下,路径损耗指数、浮动截距和由相对角度引起的路径损耗(Path Loss caused by Relative Angle,PLRA)均与相对角度具有三角函数关系;在收发端相对角度固定时,PLRA与收发端距离无关,仅与相对角度有关。上述研究结果可以为11 GHz频段在未来室内无线体域网的使用提供理论基础与实践依据。
文摘对2幅不同角度、不同光照条件或不同相机采集到的图像进行配准,是一项十分具有挑战性的研究。针对参考图像和待配准图像对之间存在的仿射变换问题,提出了一种灵活通用的、基于SIFT特征和角度相对距离的图像配准算法。算法充分利用了图像正确匹配特征点对之间存在的角度关系,实现了特征点之间的精确匹配。将所提算法同LLT(locally linear transforming)算法及RANSAC算法进行了对比实验,结果表明,新算法有较高的有效性和鲁棒性。而且新算法不仅适用于普通图像,在近红外与可见光图像以及遥感图像中均充分体现了良好的鲁棒性和适用性,在匹配特征点数目较少时,也具有良好的鲁棒性。
文摘The common vibration of cable caused by rain-wind combination has been known as most typical type and a lot kind of its countermeasures has been proposed for suppressing this phenomenon. Recently, stayed-cables were also proved that they could be excited in dry state （without rain）, which is called dry-galloping. Recently, its mechanisms have been explained by axial flow, Reynolds number and so on. To clarify the characteristics of this galloping, wind tunnel test of a cable model with various kinds of wind angle was conducted. Then, three types of countermeasure were examined to suppress dry- galloping of bridge cable. The tests confirmed that the occurrence of dry-galloping depends on relative wind attacked angles and onset reduced wind speed. Furthermore, single spiral wire, double spiral wire and circular ring were found to have high effectiveness in mitigating this galloping when those are installed properly.
