Underground coal mining inevitably results in land surface subsidence.Acquiring information on land surface subsidence is important in the detection of surface change.However,conventional data acquisition techniques c...Underground coal mining inevitably results in land surface subsidence.Acquiring information on land surface subsidence is important in the detection of surface change.However,conventional data acquisition techniques cannot always retrieve information on whole subsidence area.This study focuses on the reconstruction of a digital elevation model（DEM） with terrestrial laser scanning（TLS） point cloud data.Firstly,the methodology of the DEM with terrestrial 3-dimensional laser scanning is introduced.Then,a DEM modeling approach that involves the application of curved non-uniform rational B-splines（NURBS） surface is put forward.Finally,the performance of the DEM modeling approach with different surface inverse methods is demonstrated.The results indicate that the DEM based on the point cloud data and curved NURBS surface can achieve satisfactory accuracy.In addition,the performance of the hyperbolic paraboloid appears to be better than that of the elliptic paraboloid.The reconstructed DEM is continuous and can easily be integrated into other programs.Such features are of great importance in monitoring dynamic ground surface subsidence.展开更多
in the paper, first, using the transinfinite interpolation strategy rectangular free formsurfaces with C0 and C1 cross boundary continuity are respectively generated by three of its fourboundary curves and correspondi...in the paper, first, using the transinfinite interpolation strategy rectangular free formsurfaces with C0 and C1 cross boundary continuity are respectively generated by three of its fourboundary curves and corresponding cross derivatives. Then, their singularity is removed by anapproximation approach. Finally the surfaces are converted to the NURBS surfaces of degrees 5 × 6and 7×10 respectively. At the end of the paper, conclusions and examples are given.展开更多
The paper first summarizes the development of generating N-sided surface patches , andthen proposes a method of constructing general N-sided patches whose boundary curves and crossderivatives are Bspline curves of deg...The paper first summarizes the development of generating N-sided surface patches , andthen proposes a method of constructing general N-sided patches whose boundary curves and crossderivatives are Bspline curves of degree 3. The patch constructed is made up of n rectangularNURBS subpatches of degrees 7 ×7. The method is implemented in two steps : first , an N-sidedGregory patch is constructed, then, using our recent research on blended B-spline surface, nrectangular NURBS subpatches of degrees 7×7 are constructed to form an Nsided patch in termsof the data calculated in the first step. At the end of the paper , conclusions and some examples aregiven.展开更多
基金Project(51174206)supported by the National Natural Science Foundation of ChinaProject(2014ZDPY29)supported by the Fundamental Research Funds for the Central UniversitiesProject(SZBF 2011-6-B35)supported by the Priority Academic Program Development of Higher Education Institutions(PAPD)of Jiangsu Province,China
文摘Underground coal mining inevitably results in land surface subsidence.Acquiring information on land surface subsidence is important in the detection of surface change.However,conventional data acquisition techniques cannot always retrieve information on whole subsidence area.This study focuses on the reconstruction of a digital elevation model（DEM） with terrestrial laser scanning（TLS） point cloud data.Firstly,the methodology of the DEM with terrestrial 3-dimensional laser scanning is introduced.Then,a DEM modeling approach that involves the application of curved non-uniform rational B-splines（NURBS） surface is put forward.Finally,the performance of the DEM modeling approach with different surface inverse methods is demonstrated.The results indicate that the DEM based on the point cloud data and curved NURBS surface can achieve satisfactory accuracy.In addition,the performance of the hyperbolic paraboloid appears to be better than that of the elliptic paraboloid.The reconstructed DEM is continuous and can easily be integrated into other programs.Such features are of great importance in monitoring dynamic ground surface subsidence.
文摘in the paper, first, using the transinfinite interpolation strategy rectangular free formsurfaces with C0 and C1 cross boundary continuity are respectively generated by three of its fourboundary curves and corresponding cross derivatives. Then, their singularity is removed by anapproximation approach. Finally the surfaces are converted to the NURBS surfaces of degrees 5 × 6and 7×10 respectively. At the end of the paper, conclusions and examples are given.
文摘The paper first summarizes the development of generating N-sided surface patches , andthen proposes a method of constructing general N-sided patches whose boundary curves and crossderivatives are Bspline curves of degree 3. The patch constructed is made up of n rectangularNURBS subpatches of degrees 7 ×7. The method is implemented in two steps : first , an N-sidedGregory patch is constructed, then, using our recent research on blended B-spline surface, nrectangular NURBS subpatches of degrees 7×7 are constructed to form an Nsided patch in termsof the data calculated in the first step. At the end of the paper , conclusions and some examples aregiven.
