
CCTVSurveillanceSystem Closed-circuittelevision(CCTV),alsoknownasvideosurveillance,istheuseofvideo camerastotransmitasignaltoaspecificplace,onalimitedsetofmonitors.Itdiffersfrom broadcasttelevisioninthatthesignalisnotopenlytransmitted,thoughitmayemploypointtopoint(P2P),pointtomultipoint,ormeshwirelesslinks.Thoughalmostallvideocamerasfitthisdefinition,thetermismostoftenappliedtothoseusedforsurveillanceinareasthatmayneedmonitoringsuchasbanks,casinos,airports,militaryinstallations,andconveniencestores.Videotelephonyisseldomcalled"CCTV"buttheuseofvideoindistanceeducation,whereitisanimportanttool,isoftensocalled. Inindustrialplants,CCTVequipmentmaybeusedtoobservepartsofaprocessfromacentral controlroom,forexamplewhentheenvironmentisnotsuitableforhumans.CCTVsystemsmayoperatecontinuouslyoronlyasrequiredtomonitoraparticularevent.AmoreadvancedformofCCTV,utilizingdigitalvideorecorders(DVRs),providesrecordingforpossiblymanyyears,withavarietyofqualityandperformanceoptionsandextrafeatures(suchasmotiondetectionandemailalerts).Morerecently,decentralizedIPcameras,someequippedwithmegapixelsensors,supportrecordingdirectlytonetwork-attachedstoragedevices,orinternalflashforcompletelystand-aloneoperation.SurveillanceofthepublicusingCCTVisparticularlycommoninmanyareasaroundtheworld.Inrecentyears,theuseofbodywornvideocamerashasbeenintroducedasanewformofsurveillance.