基于立体正射影像对的三维立体景观设计方法研究

三维立体景观设计是数字城市的重要载体,在优化城市景观布局、协调城市整体发展规划、调动市民参与城市建设的积极性等方面具有积极意义。本文提出了一种基于立体正射影像对的三维立体景观设计方法,实现以可量测的形式快速构建三维立体景观模型,基于VS2012开发环境,开发了对应的软件系统。以某三线城市为案例验证表明该方法具有效率高、三维真实感强、可视化等优势,满足三维立体景观设计的一般性需求。

基于立体正射影像对的三维园林景观生成系统研究

传统三维园林景观设计多采用要素点分割并通过专用三维软件进行拼接模型的构建,存在效率低、真实感差、视觉纹理性差等不足,无法适应大规模城市三维园林景观设计需求。提出了一种融合蚁群算法的基于立体正射影像对的三维园林景观自动生成方法,实现基于最优纹理路径选取的、可量测的、可见即所得的形式快速构建三维园林景观模型,基于VS2016开发环境,开发了对应的软件系统。以我国西部某省会城市为应用载体进行案例验证,案例验证表明融合蚁群算法的基于立体正射影像对的三维园林景观自动生成方法具有实时强、自适应性好、效率高、三维真实感强、可视化等优势,满足现代城市三维园林景观快速生成的一般性需求。

Experimental Study on Full-Surface Buckling of Variable Curvature Cylindrical Shell Using Multi-camera 3D-DIC System

To achieve full-surface strain measurement of variable curvature objects,a 360°3D digital image correlation(DIC)system is proposed.The measurement system consists of four double-camera systems,which capture the object’s entire surface from multiple angles,enabling comprehensive full-surface measurement.To increase the stitching quality,a hierarchical coordinate matching method is proposed.Initially,a 3D rigid body calibration auxiliary block is employed to track motion trajectory,which enables preliminary matching of four 3D-DIC sub-systems.Subsequently,secondary precise matching is performed based on feature points on the test specimen’s surface.Through the hierarchical coordinate matching method,the local 3D coordinate systems of each double-camera system are unified into a global coordinate system,achieving 3D surface reconstruction of the variable curvature cylindrical shell,and error analysis is conducted on the results.Furthermore,axial compression buckling experiment is conducted to measure the displacement and strain fields on the cylindrical shell’s surface.The experimental results are compared with the finite element analysis,validating the accuracy and effectiveness of the proposed multi-camera 3D-DIC measuring system.

Analysis on accuracy of Engineering Star RTK in cadastral survey based on SOUTH-CORS

Currently,with the fast development of GPS technique,GPS RTK is rapidly being applied to the cadastral survey. GPS RTK technique not only improves efficiency and accelerates the rate of mapping,but also increases economic efficiency. The authors introduced a method for GPS RTK rapid positioning,which uses continuous operational reference system (CORS) as a base station to change the method of previous map drawing by obtaining real-time three-dimensional coordinates of boundary points and statistically analyzing with the three-dimensional coordinates obtained by Total Station to get the accuracy of GPS RTK real-time coordinates. The application of GPS RTK in practical measurement was discussed when the data link had been lost especially. The results show that the three-dimensional coordinates measured by total station can be replaced by real-time three-dimensional coordinates measured by Engineering Star RTK in the CORS.

Influence of Adoptment of Geocentric 3D Coordinate System on Chinese Existent Maps

If a geocentric 3D coordinate system is adopted in China to replace 2D non-geocentric coordinate system, the coordinates of the surface points will be changed accordingly. The influences on the current maps of China, especially the topographic maps, are discussed due to the replacement of the coordinate systems. Taking the replacement of Xi’an 80 coordinate system by GRS80 for a numerical example, this paper analyzes the changes of latitude, longitude, Gauss plane coordinates of the surface points, as well as the orientation and the length changes between the points on the map, including the changes of map border lines and sheet corner points.

全站仪RDM法与3D量测法量测隧道变形精度对比

根据测量学原理和误差传播定律,分析了全站仪自由设站对边量测(RDM)法和三维坐标(3D)量测法,建立了2种量测法的隧道变形精度分析模型,利用中误差评价隧道变形量测精度,推导了2种方法量测隧道变形的中误差计算公式,并以某三车道公路隧道为例,对2种方法的量测精度进行了对比和验证;RDM法通过三角高程测量原理和三角余弦定理得出任意点之间的水平距离、高差和斜距,根据任意测点之间的三角几何关系得到隧道变形;3D量测法从任意观测点观测若干已知点的方向和距离,通过坐标变换计算各测点坐标,根据各测点坐标得到隧道变形。分析结果表明:采用RDM法和3D量测法量测隧道拱顶下沉的精度评价公式相同,而量测隧道水平收敛的精度评价公式不同,RDM法的精度优于3D量测法,且随着全站仪到量测断面距离的增加,差值逐渐增大,当距离为100 m时,两者精度差值已增大至0.43 mm;在三车道公路隧道中,当距离为40~60m时,2种方法量测隧道水平收敛的精度均为最高,RDM法可达0.61~0.68mm,3D量测法可达0.78~0.84mm;RDM法和3D量测法量测的隧道拱顶下沉曲线平滑、圆顺,拟合度都大于0.95,而在量测隧道净空收敛方面,RDM法的曲线拟合度大于0.9,3D量测法的曲线拟合度小于0.9,因此,RDM法量测精度优于3D量测法。