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【英文标准名称】:StandardPracticeforDeterminingContrastSensitivityinRadioscopy
【原文标准名称】:射线检验中测定衬比灵敏度的标准实施规程
【标准号】:ASTME1647-2009
【标准状态】:现行
【国别】:美国
【发布日期】:2009
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:E07.01
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:contrastsensitivitygauge;gammaray;imageformation;imageprocessing;imagequalityindicator;line-pairspermillimeter;penetratingradiation;spatialresolution;X-ray;Contrastsensitivity;Gammaradiation;Imageanalysis;IQI(imagequalit
【摘要】:Thecontrastsensitivitygaugemeasurescontrastsensitivityindependentoftheimagingsystemspatialresolutionlimitations.Thethicknessrecessdimensionsofthecontrastsensitivitygaugearelargewithrespecttothespatialresolutionlimitationsofmostimagingsystems.Fourlevelsofcontrastsensitivityaremeasured:4%,3%,2%,and1%.Thecontrastsensitivitygaugeisintendedforuseinconjunctionwithahigh-contrastresolutionmeasuringgauge,suchastheEN462x2013;5DuplexWireImageQualityIndicator.Suchgaugesmeasurespatialresolutionessentiallyindependentoftheimagingsystem''scontrastsensitivity.Suchmeasurementsareappropriateforthequalificationandperformancemonitoringofradiographicandradioscopicimagingsystemswithfilm,realtimedevices,ComputedRadiography(CR)andDigitalDetectorArrays(DDA).Radioscopic/radiographicsystemperformancemaybespecifiedbycombiningthemeasuredcontrastsensitivityexpressedasapercentagewiththespatialresolutionexpressedinmillimetersofunsharpness.FortheEN462x2013;5spatialresolutiongauge,theunsharpnessisequaltotwicethewirediameter.Forthelinepairgauge,theunsharpnessisequaltothereciprocaloftheline-pair/mmvalue.Asanexample,animagingsystemthatexhibits2%contrastsensitivityandimagesthe0.1mmEN462x2013;5pairedwires(equivalenttoimaging5line-pairs/millimeterresolutiononaline-pairgauge)performsata2%x2013;0.2mmsensitivitylevel.AstandardmethodofevaluatingoverallradioscopicsystemperformanceisgiveninPracticeE1411andinEN13068x2013;1andforCRitcanbefoundinPracticeE2445.1.1Thispracticecoversthedesignandmaterialselectionofacontrastsensitivitymeasuringgaugeusedtodeterminetheminimumchangeinmaterialthicknessordensitythatmaybeimagedwithoutregardtospatialresolutionlimitations.1.2Thispracticeisapplicabletotransmitted-beamradiographicandradioscopicimagingsystemsutilizingX-rayandgammarayradiationsources.1.3Thevaluesstatedininch-poundunitsaretoberegardedasstandard.TheSIunitsgiveninparenthesesareforinformationonly.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.Forspecificsafetystatements,seeNIST/ANSIHandbook114Section8,CodeofFederalRegulations21CFR1020.40and29CFR1910.96.
【中国标准分类号】:H26
【国际标准分类号】:
【页数】:5P.;A4
【正文语种】:英语