【英文标准名称】:StandardPracticeforDeterminingContrastSensitivityinRadioscopy
【原文标准名称】:射线检查法中对比灵敏度测定的标准实施规范
【标准号】:ASTME1647-2003
【标准状态】:现行
【国别】:
【发布日期】:2003
【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】:图像质量;图像质量指示器;直线;γ辐射;射线检查;放射性照射;辐照;试验
【英文主题词】:contrastsensitivitygage;gammaray;imageformation;imageprocessing;imagequalityindicator;line-pairspermillimeter;penetratingradiation;spatialresolution;X-ray
【摘要】:Thecontrastsensitivitygagemeasurescontrastsensitivityindependentoftheimagingsystemspatialresolutionlimitations.Thethicknessrecessdimensionsofthecontrastsensitivitygagearelargewithrespecttothespatialresolutionlimitationsofmostimagingsystems.Fourlevelsofcontrastsensitivityaremeasured:4%,3%,2%,and1%.Thecontrastsensitivitygageisintendedforuseinconjunctionwithahigh-contrastresolutionmeasuringgage,suchastheEN462x2013;5DuplexWireImageQualityIndicator.Suchgagesmeasurespatialresolutionessentiallyindependentoftheimagingsystem’contrastsensitivity.Suchmeasurementsareappropriateforthequalificationandperformancemonitoringofradiographicandradioscopicimagingsystems.Radioscopic/radiographicsystemperformancemaybespecifiedbycombiningthemeasuredcontrastsensitivityexpressedasapercentagewiththespatialresolutionexpressedinmillimetersofunsharpness.FortheEN462x2013;5spatialresolutiongage,theunsharpnessisequaltotwicethewirediameter.Forthelinepairgage,theunsharpnessisequaltothereciprocaloftheline-pair/mmvalue.Asanexample,animagingsystemthatexhibits2%contrastsensitivityandimagesthe0.1mmEN462x2013;5pairedwires(equivalenttoimaging5line-pairs/millimeterresolutiononaline-pairgage)performsata2%x2013;0.2mmsensitivitylevel.AstandardmethodofevaluatingoverallradioscopicsystemperformanceisgiveninPracticeE1411andinEN13068x2013;1.1.1Thispracticecoversthedesignandmaterialselectionofacontrastsensitivitymeasuringgageusedtodeterminetheminimumchangeinmaterialthicknessordensitythatmaybeimagedwithoutregardtospatialresolutionlimitations.1.2Thispracticeisapplicabletotransmitted-beamradiographicandradioscopicimagingsystemsutilizingX-rayandgammarayradiationsources.1.3Thevaluesstatedininch-poundunitsaretoberegardedasstandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.Forspecificsafetystatements,seeNIST/ANSIHandbook114Section8,CodeofFederalRegulations21CFR1020.40and29CFR1910.96.
【中国标准分类号】:C43
【国际标准分类号】:
【页数】:5P.;A4
【正文语种】: