Designation:F1811–97StandardPracticeforEstimatingthePowerSpectralDensityFunctionandRelatedFinishParametersfromSurfaceProfileData1ThisstandardisissuedunderthefixeddesignationF1811;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticedefinesthemethodologyforcalculatingasetofcommonlyusedstatisticalparametersandfunctionsofsurfaceroughnessfromasetofmeasuredsurfaceprofiledata.Itspurposesaretoprovidefundamentalproceduresandnota-tionforprocessingandpresentingdata,toalertthereadertorelatedissuesthatmayariseinuser-specificapplications,andtoprovideliteraturereferenceswherefurtherdetailscanbefound.1.2Thepresentpracticeislimitedtotheanalysisofone-dimensionalorprofiledatatakenatuniformintervalsalongstraightlinesacrossthesurfaceundertest,althoughreferenceismadetothemoregeneralcaseoftwo-dimensionalmeasure-mentsmadeoverarectangulararrayofdatapoints.1.3Thedataanalysisproceduresdescribedinthispracticearegenericandarenotlimitedtospecificsurfaces,surface-generationtechniques,degreesofroughness,ormeasuringtechniques.Examplesofmeasuringtechniquesthatcanbeusedtogenerateprofiledataforanalysisaremechanicalprofilinginstrumentsusingarigidcontactingprobe,opticalprofilinginstrumentsthatsampleoveralineoranarrayoveranareaofthesurface,opticalinterferometry,andscanning-microscopytechniquessuchasatomic-forcemicroscopy.ThedistinctionsbetweendifferentmeasuringtechniquesenterthepresentpracticethroughvariousparametersandfunctionsthataredefinedinSections3and5,suchastheirsamplingintervals,bandwidths,andmeasurementtransferfunctions.1.4Theprimaryinteresthereisthecharacterizationofrandomorperiodicaspectsofsurfacefinishratherthanisolatedsurfacedefectssuchaspits,protrusions,scratchesorridges.Althoughthemethodsofdataanalysisdescribedherecanbeequallywellappliedtoprofiledataofisolatedsurfa...
