简介:线性调频连续波(LFMCW)与圆锥扫描(cs)相结合的雷达体制,可在获得目标高分辨距离像的同时分别测得各个散射中心的角度信息,从而有利于对距离扩展目标的检测和识别。文中给出了圆锥扫描线性调频连续波(CS-LFMCW)雷达信号的形式,研究了角度信息提取方法,详细分析了噪声、天线旋转不稳定、泄漏、弹体旋转等非理想因素对角度信息提取精度的影响,并提出了相应的解决方法。仿真结果验证了分析的有效性。圆锥扫描线性调频连续波雷达具有距离分辨率高、结构简单、体积小、重量轻、能够获取角度信息等优点,因此在近距离、末制导雷达中有着广泛的应用前景。
简介:Inordertosolvetheproblemoflowrecognitionrateoftraditionalfeatureextractionoperatorsunderlow-resolutionimages,anovelalgorithmofexpressionrecognitionisproposed,namedcentralobliqueaveragecenter-symmetriclocalbinarypattern(CS-LBP)withadaptivethreshold(ATCS-LBP).Firstly,thefeaturesoffaceimagescanbeextractedbytheproposedoperatorafterpretreatment.Secondly,theobtainedfeatureimageisdividedintoblocks.Thirdly,thehistogramofeachblockiscomputedindependentlyandallhistogramscanbeconnectedseriallytocreateafinalfeaturevector.Finally,expressionclassificationisachievedbyusingsupportvectormachine(SVM)classifier.ExperimentalresultsonJapanesefemalefacialexpression(JAFFE)databaseshowthattheproposedalgorithmcanachievearecognitionrateof81.9%whentheresolutionisaslowas16×16,whichismuchbetterthanthatofthetraditionalfeatureextractionoperators.
简介:Theopticalparametersforthreesamplesofintrinsic,dopedSianddopedMg(AlxGa1-x)yIn1-yPpreparedbytheMOCVDonGaAssubstrateweremeasuredbyusingellipsometryandwerecalculatedbythetwo-layerabsorptionfilmmodel.Theresultsobtainedwerediscussed.Thegrownratesandthicknessofoxidiclayerontheintrinsic(AlxGa1-x)yIn1-yPsurfaceexposedintheatmospherewerestudied.Alineardependenceofoxidiclayerthicknessonthetimewasobtained.