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基于Huffman编码的DSP图像无损压缩系统.docx

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基于Huffman编码的DSP图像无损压缩系统 Abstract HuffmanencodingisawidelyusedtechniqueforlosslesscompressionofDSPimages.ThispaperdiscussestheimplementationofaHuffmanencodingbasedDSPimagecompressionsystem.Thesystemcancompressanddecompressimagefileswithoutlossofinformationandachievehighcompressionratios.ThepaperalsodiscussesthetheoreticalbackgroundofHuffmancoding,thepracticalimplementationconsiderationsandtheperformanceevaluationofthedevelopedsystem. Introduction Digitalsignalprocessing(DSP)isubiquitousinmodernelectronicdevicessuchasmobilephones,digitalcamerasandtelevisionsets.DSPimagesareoftenusedinthesedevices,andthestorageandtransmissionofDSPimagesisanimportantissue.ThehighdataraterequiredforDSPimagesmakestheirtransmissionandstorageproblematic.Losslesscompressionisoftenusedtoreducethesizeofimagedatawhilepreservingthequalityoftheimage.Huffmancodingisawidelyusedtechniqueforthispurpose,asitcanprovidehighcompressionratioswhilemaintainingtheoriginaldata. HuffmanEncoding Huffmanencodingisamethodofvariable-lengthcodingthatisusedtoreducetheamountofdataneededtorepresentamessage.InHuffmancoding,afrequencyanalysisoftheinputdataisperformedandavariablelengthcodeisassignedtoeachcharacterbasedonthefrequencyofitsoccurrence.Characterswithhigherfrequenciesareassignedshortercodeswhilethosewithlowerfrequenciesareassignedlongercodes.Thisallowsfortheconstructionofacodetablewherethemostfrequentlyoccurringcharactersarerepresentedbyshortercodes,therebyreducingtheoverallsizeofthedata. Huffmancodingcanproduceanoptimalcodeintermsofreducingthesizeofthedataforagivenmessage.Thealgorithmworksbyconstructingabinarytreeinwhicheachleafnoderepresentsacharacterandthepathfromtheroottotheleafnoderepresentsthecodeforthatcharacter.Thetreeisconstructedbyrepeatedlymergingthetwoleastfrequentcharactersuntiltheentiresetofcharactersisrepresentedbyasinglesubtree.Theprocessisthenreversedtobuildacodetablefromthetree. ImplementationConsiderations Huffmancodingcanbeimplementedinhardwareorsoftware,dependingontherequirementsofthesyste