简介:为实现多光谱TDICCD的高速高信噪比成像,利用可空间应用的多光谱TDICCD传感器研制出了高性能成像电路系统。该系统以现场可编程门阵列(FPGA)为核心逻辑单元,带有RS422外围通信控制接口,并采用CAMERALINK接口输出图像数据。系统具有动态推扫成像的能力,可同时输出全色和彩色两种模式的图像数据。利用灰度条纹的靶标对传感器的3个多光谱(R、G、B)感光区标定白平衡,利用彩色条纹的靶标对系统进行成像测试,在驱动频率为15MHz的情况下,系统单片CCD输出的图像数据率达到1.2Gbps。试验结果表明,获取全色图像的信噪比达到了53.56dB,各多光谱图像的信噪比较高的也在40dB以上,满足空间对地高分辨多光谱遥感成像的技术指标要求,对高速空间多光谱遥感相机的研制具有借鉴意义。
简介:Inordertoimprovetheresolutionofdigitalholographywithacommon-dimensioncharge-coupleddevice(CCD)sensor,thepointspreadfunctionsarebrieflyderivedforthecommonlyusedandpracticalpost-magnification,pre-magnification,andimage-planedigitalholographicmicroscopicsystems.Theultimateresolutionsofthesesystemsareanalyzedandcompared.Theresultsshowthattheultimatelateralresolutionofpre-magnificationdigitalholographyissuperiortothatofpost-magnificationdigitalholographyinthesameconditions.Wealsodemonstratethattheultimatelateralresolutionofimage-planedigitalholographyhasnocorrelationwiththephotosensitivedimensionoftheCCDsensor,anditisnotsignificantlyrelatedtothepixelsizeofthesensor.Moreover,boththeultimateresolutionandtheimagingqualityofimage-planedigitalholographyaresuperiortothatofpre-andpost-magnificationdigitalholographicmicroscopy.High-resolutionimaging,whoseresolutionisclosetotheultimateresolutionofthemicroscopeobjective,canbeachievedbyimage-planedigitalholographyevenwithasubmillimeter-dimensionsensor.Thissystem,bywhichperfectimagingcanbeachieved,isoptimalforcommonlyuseddigitalholographicmicroscopy.Experimentalresultsdemonstratethecorrectnessofthetheoreticalanalysis.
简介:AsoneofthekeyunitsofspaceCCDcamera,thetemperaturerangeandstabilityofCCDcomponentsaffecttheimage’sindexes.Reasonablethermaldesignandrobustthermalcontroldevicesareneeded.Onekindoftemperaturecontrolloopheatpipe(TCLHP)isdesigned,whichhighlymeetsthethermalcontrolrequirementsofCCDcomponents.InordertostudythedynamicbehaviorsofheatandmasstransferofTCLHP,particularlyintheorbitalflightcase,atransientnumericalmodelisdevelopedbyusingthewell-establishedempiricalcorrelationsforflowmodelswithinthreedimensionalthermalmodeling.Thetemperaturecontrolprincipleanddetailsofmathematicalmodelarepresented.Themodelisusedtostudyoperatingstate,flowandheatcharacteristicsbasedupontheanalysesofvariationsoftemperature,pressureandqualityunderdifferentoperatingmodesandexternalheatfluxvariations.TheresultsindicatethatTCLHPcansatisfythethermalcontrolrequirementsofCCDcomponentswell,andalwaysensuregoodtemperaturestabilityanduniformity.Bycomparisonbetweenflightdataandsimulatedresults,itisfoundthatthemodelistobeaccuratetowithin1℃.ThemodelcanbebetterusedforpredictingandunderstandingthetransientperformanceofTCLHP.