Implement of Digital Moire technique on DSP for alignment of partial compensation interferometer

摘要

DigitalMoirétechniqueisadoptedinpartialcompensationinterferometer(PCI)forhigh-precisiontestingoffigureerroroftheasphericsurfaces.Thefigureerrorofthemeasuredasphericisobtainedbyaseriesofcalculationwiththerealinterferogramandidealinterferogramsgeneratedbycomputer.ThedenseinterferencefringesattheexitpupilmakeitdifficulttoalignthePCI.Onthecontrary,digitalMoirefringescomposedfromrealandidealinterferogramsaresparseandcorrespondingtothefigureerrorofthemeasuredaspheric,makingiteasiertoalignthePCI.Generally,digitalMoiretechniqueisprocessedonthecomputer,resultinginslowprocessingspeedanddifficultdisplayinrealtime.DigitalSignalProcessor(DSP)canbeusedtoimplementdigitalMoiretechniqueanddisplaydigitalMoirefringesinrealtimewithitspowerfulprocessingcapacity.Inthispaper,digitalMoiretechniqueisimplementedontheTMS320C6455DSP.ThehardwaresystemconsistsofaDSPmodule,aCCDcameraandamonitor.FinallyweexperimentallyobtainthedigitalMoireimage,andfurtheranalyzehowtoalignthePCItheoretically...