Product Manual

FLIRCM174USERMANUALDocumentIdentifier:CM174‐en‐US_AB

5.10.3InfraredEnergyandImagingTheory

Athermalimagergeneratesanimagebasedontemperaturedifferences.Inathermalimage

thehottestiteminthesceneappearsaswhiteandthecoldestitemasblack,andallother

itemsarerepresentedasagrayscalevaluebetweenwhiteandblack.

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Itmaytakesometimeto

getusedtothethermalimagery.Havingabasicunderstandingofthe

differencesbetweenthermalanddaylightcamerascanhelpwithgettingthebestperformance

fromtheCM174.

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Onedifferencebetweenthermalanddaylightcamerashastodowithwheretheenergycomes

fromtocreateanimage.Whenviewinganimagewithanordinarycamera,therehastobe

somesourceofvisiblelight(somethinghot,suchasthesunorlights)thatreflects offofthe

objectsinthescenetothecamera.Thesameistruewithhumaneyesight;thevastmajorityof

whatpeopleseeisbasedonreflectedlightenergy.Ontheotherhand,thethermalimager

detectsenergythatisdirectlyradiatedfromobjectsinthescene.

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Thisiswhyhotobjectssuchaspartsonanenginesandexhaustpipesappearwhite,whilethe

sky,puddlesofwaterandothercoldobjectsappeardark(or

cool).Sceneswithfamiliarobjects

willbeeasytointerpretwithsomeexperience.

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Infraredenergyispartofacompleterangeofradiationcalledtheelectromagneticspectrum.

Theelectromagneticspectrumincludesgammarays,X‐rays,ultraviolet,visible,infrared,

microwaves(RADAR),andradiowaves.Theonlydifferenceistheirwavelengthorfrequency.All

oftheseformsofradiationtravelatthespeedoflight.Infraredradiationliesbetweenthe

visibleandRADARportionsoftheelectromagneticspectrum.

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Theprimarysourceofinfraredradiationisheatorthermalradiation.Anyobjectwhichhasa

temperatureradiatesintheinfraredportionoftheelectromagnetic

spectrum.Evenobjects

thatareverycold,suchasanicecube,emitinfrared.Whenanobjectisnotquitehotenoughto

radiatevisiblelight,itwillemitmostofitsenergyintheinfrared.Forexample,hotcharcoal

maynotgiveofflight,butitdoesemitinfraredradiation,whichwefeelasheat.Thewarmer

theobject,themoreinfraredradiationitemits.

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Infraredimagingdevicesproduceanimageofinvisibleinfraredor“heat”radiationthatis

unseenbythehumaneye.Therearenocolorsor“shades”ofgrayininfrared,onlyvarying

intensitiesofradiated

energy.Theinfraredimagerconvertsthisenergyintoanimagethatwe

caninterpret.

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TheInfraredTrainingcenterofferstraining(includingonlinetraining)andcertificationinall

aspectsofthermography:http://www.infraredtraining.com/.