简介：Calibratingasmallfieldcameraisachallengingtaskbecausethetraditionaltargetwithvisiblefeaturepointsthatfitthelimitedspaceisdifficultandcostlytomanufacture.Wedemonstrateanovelcombinedtargetusedincameracalibration.Thetangentpointssuppliedbyonecirclelocatedatthecenterofasquareareusedasinvisiblefeatures,andtheperspectiveprojectioninvarianceisproved.Bothvisibleandinvisiblefeaturesextractedbytheproposedfeatureextractionalgorithmareusedtosolvethecalibration.Thetargetsuppliesasufficientnumberoffeaturepointstosatisfytherequirementsofcalibrationwithinalimitedspace.Experimentsshowthattheapproachcanachievehighrobustnessandconsiderableaccuracy.Thisapproachhaspotentialforcomputervisionapplicationsparticularlyinsmallfieldsofview.

简介：Amethodtothree-dimensionalpositionmovingparticleswithonelensandtwocamerasisproposed.Twoparticleimageswithdifferentdegreesofdefocusingareadoptedtosolvetheambiguousproblemofparticlepositions.Asingle-lensdual-camerasystemisdevelopedtosimultaneouslycapturethesetwoimagesforthemovingparticles.Themeasurementprinciplesandtheoreticalanalysisareintroducedfirst,andthensimulatedinvestigationsandexperimentalresearcharediscussed.Themeasurementerrorsinthesimulationsandexperimentsarelessthan1%and4%,respectively,in20timesthedepthoffieldofthesystem,whichvalidatesthefeasibilityofthismethod.