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1、西南交通大學(xué)研究生學(xué)位論文基于FPGA的圖像處理算法及壓縮編碼的研究與實現(xiàn)矩姓級三QQ望絲名塹!墾鋈申請學(xué)位級別王堂亟±專業(yè)出鱟三堡指導(dǎo)教師高疃鎣絲蕉二oo七年三月摘要本文以“機(jī)車車輛輪對動態(tài)檢測裝置”為研究背景,以改進(jìn)提升裝置性能為目標(biāo),研究在Altera公司的FPGA(FieldProgrammableGateArray)芯片Cyclone上實現(xiàn)圖像采集控制、圖像處理算法、JPEG(JointPhotographicExpertGroup)壓縮編碼標(biāo)準(zhǔn)的基本系統(tǒng)。本文使用硬件描述語言Verilog
2、,以RedLogic的RVDK開發(fā)板作為硬件平臺,在開發(fā)工具QUARTUS26.0和MODELSIMSE6.1B環(huán)境中完成軟核的設(shè)計與仿真驗證。數(shù)據(jù)采集部分完成的功能是將由模擬攝像機(jī)拍攝到的圖像信號進(jìn)行數(shù)字化,然后從數(shù)據(jù)流中提取有效數(shù)據(jù),加以適當(dāng)裁剪,最后將奇偶場圖像數(shù)據(jù)合并成幀,存儲到存儲器中。數(shù)字化及碼流產(chǎn)生的功能由SAA7113芯片完成,由FPGA對SAA7113芯片初始化設(shè)置、控制,并對數(shù)字化后的數(shù)據(jù)進(jìn)行操作。圖像處理算法部分考慮到實時性與算法復(fù)雜度等因素,從裝置的圖像處磐流程中有選擇性地實現(xiàn)
3、了直方圖均衡化、中值濾波與邊緣檢測三種圖像處理算法。壓縮編碼部分依據(jù)JPEG標(biāo)準(zhǔn)基本系統(tǒng)順序編碼模式,在FPGA上實現(xiàn)了DCT(DiscreteCosineTransform)變換、量化、Zig--Zag掃描、直流系數(shù)DPCM(DifferentialPulseCodeModulation)編碼、交流系數(shù)RLC(RunLengthcode)編碼、霍夫曼編碼等主要步驟,最后用實際的圖像數(shù)據(jù)塊對系統(tǒng)進(jìn)行了驗證。關(guān)鍵詞FPGA;圖像處理;直方圖均衡化;中值濾波;邊緣檢測;DCT變換;霍夫曼編碼Abstrac
4、tWiththebackgmundof“thedramaticinspectequir'meritofvehiclewheels”andtheaimofimprovingtheperformanceoftheequipment,thispaperstudiesabouttherealizationofimagecollectionandcontrol,imageprocessingalgorithm,andJPEGbasicsystemonthechipCyclonefromtheAlteracomp
5、any’sFPGA.WiththehardwareplatformoftheRedlogic’sRVDK,itcompletesthedesignandthesimulativeconfirmationofthesoftcorewitht11ehardwaredescriptive1anguageVerilogintheenvironmentoftheexploitedt001QUARTUS26,0andMODELSIM—SE6.1B.Thefunctionoftheimagecollectionpa
6、rtistoconverttheanalogdatafromtheanalogcameraintothedigitaldata,andthentopickuptheusefuldatafromthedataflow,andfmallytoincorporate也eoddandevenfieldintoaflameandsaveittoamemoryaftertheappropriatecut.111efunctionproducedbythedigitaldataflowiscompletedbvSA
7、A7113chip,however,FPGAchipinitializesandcontrolstheSAA7ll3chip.a(chǎn)ndmanipulatesthedigitaldataaswell.1址ingaccountofsomefactorssuchasrealtimecharactercomplexityofalgorithm,theimageprocessingalgorithmpartchosethreealgorithmstorealize,theywerehistogramequaliz
8、ation,medianflterandedgeinspection,AccordingtotheordercodingmodeoftheJPEGbasicsystem,thecompressedcodepartrealizedDCTtransforrn,quantized,Zig--Zagscan,DPCMencodingofdirectcurrenttoefficient,RLCencodingofalternatingcurrentcoeffici