Designation:E1311−14StandardPracticeforMinimumDetectableTemperatureDifferenceforThermalImagingSystems1ThisstandardisissuedunderthefixeddesignationE1311;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thispracticecoversthedeterminationoftheminimumdetectabletemperaturedifference(MDTD)capabilityofacompoundobserver-thermalimagingsystemasafunctionoftheanglesubtendedbythetarget.1.2ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyproblems,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2E1316TerminologyforNondestructiveExaminations3.Terminology3.1Definitions:3.1.1differentialblackbody—anapparatusforestablishingtwoparallelisothermalplanarzonesofdifferenttemperatures,andwitheffectiveemissivitiesof1.0.3.1.2fieldofview(FOV)—theshapeandangulardimen-sionsoftheconeorthepyramidthatdefinetheobjectspaceimagedbythesystem;forexample,rectangular,4-degwideby3-deghigh.3.1.2.1Discussion—Thesizeofthefieldofviewiscustom-arilyexpressedinunitsofdegrees.3.1.3SeealsoTerminologyE1316.4.SummaryofPractice4.1Astandardcirculartargetisusedinconjunctionwithadifferentialblackbodythatcanestablishoneblackbodyisother-maltemperatureforthetargetandanotherblackbodyisother-maltemperatureforthebackgroundbywhichthetargetisframed.Thetarget,atanundisclosedorientation,isimagedontothemonochromevideomonitorofathermalimagingsystemwhencetheimagemaybeviewedbyanobserver.Thetemperaturedifferencebetweenthetargetandthebackground,initiallyzero,isincreasedincrementallyuntiltheobserver,inalimitedduration,canjustdistinguishthetarget.T...
