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基于视觉的电子激光经纬仪空间点自动瞄准方法 被引量:3
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作者 周虎 邾继贵 叶声华 《传感技术学报》 CAS CSCD 北大核心 2011年第8期1204-1207,共4页
为提高电子经纬仪系统的工作效率,将图像处理技术与传统测量方法相结合,提出了基于插值算法的自动电子激光经纬仪空间点坐标测量方法。首先介绍了系统结构,接着说明了外置摄像系统在近距离长焦模式下实现光学放大,利用质心算法得到亚像... 为提高电子经纬仪系统的工作效率,将图像处理技术与传统测量方法相结合,提出了基于插值算法的自动电子激光经纬仪空间点坐标测量方法。首先介绍了系统结构,接着说明了外置摄像系统在近距离长焦模式下实现光学放大,利用质心算法得到亚像素级别的目标定位精度的方法;然后利用电子激光经纬仪扫描线模型,通过离散点插值方法得到概率瞄准状态下经纬仪对准目标质心时的精确角度值,最后通过前方交会法计算空间点三维坐标。实验数据表明,该方法可以有效提高测量效率,在20 m×20 m空间范围内获得不低于±0.02 mm/m的测量精度。 展开更多
关键词 大尺寸测量 电子经纬仪 视觉测量 扫描线模型
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Numerical simulation of asphalt mixture based on three-dimensional heterogeneous specimen 被引量:5
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作者 张肖宁 万成 +1 位作者 王栋 贺玲凤 《Journal of Central South University》 SCIE EI CAS 2011年第6期2201-2206,共6页
In order to verify the validity of finite element numerical simulation method for asphalt mixture, which consists of aggregates, mastic (where mastic is a kind of fine mixture composed of asphalt binder mixed with fi... In order to verify the validity of finite element numerical simulation method for asphalt mixture, which consists of aggregates, mastic (where mastic is a kind of fine mixture composed of asphalt binder mixed with fines and fine aggregates) and air voids, based on three-dimensional (3D) heterogeneous specimen, X-ray computerized tomography (X-ray CT) was used to scan the asphalt specimens to obtain the real internal microstrnctures of asphalt mixture. CT images were reconstructed to build up 3D digital specimen, and the viscoelastic properties of mastic were described with Burgers model The uniaxial creep numerical simulations of three different levels of aggregate gradation were conducted. The simulation results agree well with the experimental results. The numerical simulation of asphalt mixture incorporated with real 3D microstructure based on finite element method is a promising application to conduct research of asphalt concrete. Additionally, this method can increase the mechanistic understanding of global viscoelastic properties of asphalt mixtures by linking the real 3D microstructure. 展开更多
关键词 asphalt mixture X-ray CT 3D heterogeneous specimen numerical simulation
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