简介:Triangulationiswidelyusedinscientificresearch,suchasfiniteelementmeshgeneration,surfacereconstructionandthereconstructionofthedensityfielddata.Thispaperproposesanewmethodcombiningimageprocessinganddensity-controlledCentroidalVoronoitessellationstoquicklygenerateadensity-controlledconstrainedDelaunaytriangulationfor2Dseaarea.Firstly,preprocessdigitalimagesoftheseaareaandextracttheboundaryofseawaterregionbyeight-neighborsearchingalgorithm.Then,Iuse"Odd-EvenTesting"methodtocheckifonerandomvertexisinsidetheboundaryandinsertrandomverticesintotheboundary.Finally,wegettheCDTofrandomverticesbydensity-controlledCVT-Lloydmethod.Wealsogivesomecomparisonswithexistingmethods,andourmethodperformsbetterinfinalresultoftriangulation.
简介:WormandwormgeararemodeledunderdevelopmentenvironmentinAutoCADbasedontheprincipleofordinarycylindricalwormdrive.ThedrawingcommandsavailableinAutoCADareusedtodevelopwormblankandcuttermodels.Thesolidmodelsofwormandwormgearareobtainedthroughtheuseofthecommands,move,rotateandsubtract,tosimulatethegeneratingcuttingmovementonthegearcuttingmachine.Autolisplanguageisutilizedinprogrammingforparametricmodelingofwormandwormgear.Thedevelopedprogramcanautomaticallydrawwormandwormgearwhenusersloadthewlwgprogram,inputthemodulusandthenumberofthreads,handedness,andotherparameters.Theoperationissimpleandaccurate,providingpotentialstospeedupproductdesignprocessandimproveefficiency.
简介:3Dobjectscanbestoredincomputerofdifferentdescribingways,suchaspointset,polyline,polygonalsurfaceandEuclideandistancemap.Momentinvariantsofdifferentordersmayhavethedifferentmagnitude.Amethodfornormalizingmomentsof3Dobjectsisproposed,whichcansetthevaluesofmomentsofdifferentordersroughlyinthesamerangeandbeappliedtodifferent3Ddataformatsuniversally.Thenaccuratecomputationofmomentsforseveralobjectsispresentedandexperimentsshowthatthiskindofnormalizationisveryusefulformomentinvariantsin3Dobjectsanalysisandrecognition.
简介:本文阐述了G.657的性能和提高光纤抗弯曲性能的技术途径,以及Nanostructure抗弯曲光纤的性能分析。通过模拟现场的环境对整个链路插入损耗分析,证明Nanostructure抗弯曲光纤在FTTH的应用,解决了长期困扰着电信运营商们在高层建筑和公寓大楼内进行光纤到户(FTTH)网络安装的技术难题。