standardJPEG.docx
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standardJPEG.docx
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standardJPEG
DigitalimagecompressiontechnologyResearchandDevelopment
TianYong1,DINGXue-Jun2
(1.NortheasternUniversity,embeddedsystemsNeusoftInstituteofInformationEngineering,Liaoning,Dalian116023;2.NortheastUniversityofFinanceandInformationEngineering,Liaoning,Dalian116023)
Abstract:
Digitalimagecompressiontechnologyfordigitalimageinformationonthenetworkforrapidtransferandreal-timeprocessingisofgreatsignificance.Thisarticledescribesseveralofthemostimportantofthecurrentimage
Compressionalgorithms:
JPEG,JPEG2000,fractalimagecompressionandwavelettransformimagecompression,summeduptheadvantagesanddisadvantagesoftheirdevelopmentprospects.Abriefintroductionandthenarbitrarilyshapedvisualobjectcoding
Algorithmforthestatusquo,andpointedoutthatthisalgorithmisahighcompressionratioresultingimagecompressionalgorithms.
Keywords:
JPEG;JPEG2000;fractalimagecompression;wavelettransform;arbitrarilyshapedvisualobjectcoding
CLCnumber:
TP3Abstract:
AArticleID:
1672-545X(2007)04-0072-04Withthemultimediatechnologyandcommunicationtechnologycontinuestoevolve,multimediaentertainment,theletter
Interestrateshavekepttheinformationhighwaydatastorageandtransmissionshouldbesethigher
Demand,butalsotothelimitedbandwidthavailabletoaseveretest,especiallythosewithlargedata
Theamountofdigitalimagecommunication,moredifficulttotransportandstorage,whichgreatlyrestrictedtheimagepass
Thedevelopmentoftheletter,sotheimagecompressiontechnologyhasbeenmoreandmoreattention.Imagecompression
Thepurposeistoshrinktheoriginalimageofalargerlessbytesexhaustedexpressionandtransmission,
Andaskedtorecoverabetterqualityimage.Theuseofimagecompressionthatcanreducethemap
Suchastheburdenofstorageandtransmission,sothattheimageonthenetworktoachievefasttransferandreal-timeOffice
Li.
Imagecompressiontechniquescanbetracedbackto1948,raisedthenumberoftelevisionsignals
Word-oriented,andtodayhas50yearsofhistory[1].Duringthisperiodtherehavebeenmany
Kindsofimagecompressioncodingmethod,especiallyinthelate20thcentury,80yearslater,
Becausethewavelettransformtheory,fractaltheory,artificialneuralnetworktheory,visualsimulationofLi
Ontheestablishmentofimagecompressiontechnologyhasbeenanunprecedenteddevelopment,inwhichfractalimage
Imagecompressionandwaveletimagecompressionisthecurrenthotresearch.Inthispaper,present,themostwidely
Pan-useimagecompressionalgorithmsarereviewedanddiscussedtheiradvantagesanddisadvantages,aswellashair
Showprospect.
1JPEGcompression
Responsiblefordevelopingthestillimagecompressionstandard"JointPhotographicExpertGroup"(Joint
PhotographicExpertGroup,referredtoasJPEG),wasformedinJanuary1989
AdaptiveDCT-basedJPEGtechnicalspecificationsofthefirstdraft,followedbyseveral
Changestothe1991formationofthedraftinternationalstandardISO10918,andafteroneyearintothe
Asaninternationalstandard,calledJPEGstandard.
1.1JPEGcompressionprincipleandcharacteristicsof
JPEGalgorithminthefirstblockoftheimageprocessing,generallydividedintoeachotherwithoutre-
Thesizeofstackedblocks,andtheneveryonetotwo-dimensionaldiscretecosinetransform(DCT).Variable
Afterchangingcoefficientsarenotrelevant,andthecoefficientmatrixoftheenergyconcentratedinthelow-frequencyarea,theroot
Quantizationtable,accordingtoquantify,quantifytheresultsofretainedlow-frequencypartofthecoefficient,removethe
Thehigh-frequencypartofthecoefficients.ThequantizedcoefficientsbyZigzagscanre-organization,Ran
AfterHuffmancoding.JPEGfeaturesareasfollows:
Advantages:
(1)theformationofinternationalstandards;
(2)hasamid-rangeandhighbit-rateonthe
Goodimagequality.
Disadvantages:
(1)Becauseoftheimageblock,athighcompressionratiowhenyouhaveaserious
Blockingeffects;
(2)factortoquantifyisthelossycompression;(3)thecompressionratioisnothigh,small
At50[2].
JPEGcompressedimageboxeffectoccursbecause:
Undernormalcircumstancestheimage
Thesignalishighlynon-stationary,itisdifficulttocharacterizetheprocessofusingGauss,andtheimage
Someofthemutantstructure,suchastheedgeinformationthantheimagesmoothnessimportant,withthecosine-based
Non-linearapproximationforimagesignalstheresultisnotoptimal[3].
1.2JPEGcompressionstatusandprospectsofthestudy[2]
JPEGathighcompressionratioforcasesarisingundertheboxeffect,decompressestheimagethanthe
Poor,inrecentyearsmadealotofimprovementmethods,themosteffectiveisthefollowingtwoways:
(1)DCTzerotreecoding
DCTblockzero-treecodingtheDCTcoefficientsinthecompositionoflog2Nsub-zone,Ran
Afterthezero-treecodingschemeusedtoencode.Compressionratiointhesamecircumstances,the
PSNRvaluehigherthantheEZW.However,inthecaseofhighcompressionratio,theboxeffectisstill
DCTtheAchillesheelofzero-treecoding.
(2)layer-typeDCTzerotreecoding
ThealgorithmfortheDCTtransformtheimagewillbelow-frequencyblockstogether,doinganti-
DCT;pairsofnewlyacquiredimagesdothesametransformation,andsoitgoes,untilsatisfied
Requestuntilthe.ThenLayeredDCTtransformandzero-treearrangementofthecoefficientsoverzero
Treecoding.
JPEGcompressiononeofthebiggestproblemisthatathighcompressionratiowhenyouhaveaserious
Blockingeffects,sofutureresearchshouldbefocusedonsolvingtheresultingDCTtransform
Blockingeffects,takingintoaccountthehumanvisualsystemwiththecombinationofcompression.
2JEPG2000compression
JPEG2000isaISO/IECJTCISC29standardsgroupresponsibleforformulating
Thenewstillimagecompressionstandard.Oneofthebiggestimprovementsisthatituseswavelettransformonbehalfofthe
Forthecosinetransform.InMarch2000theTokyoconferencetoidentifyacolorstillimage
Encodinganewgenerationofimagecompressionstandard-JPEG2000codingalgorithm.
2.1JPEG2000compressionprincipleandcharacteristicsof
JPEG2000CodecencoderanddecoderblockdiagraminFigure1[4].
Encodingprocessismainlydividedintothefollowingprocesses:
pre-processing,coreprocessingandbit
Streamorganization.Pretreatmentsectionincludesimagesegmentation,DClevel(DC)displacementandsub-
Receiveddate:
2007-01-16
Author:
Takada(1975-),male,Master,Lecturer,majorresearchinterestsincludedigitalimageprocessing,integratedcircuitdesign,etc.;DINGXue-jun(1978-),female,master'sdegree,teachingassistants,themainresearchdirectionforinformation
Andnetworksecurity,digitalimageprocessing.Theamountofchange.Coreprocessinginpartbythediscretewavelettransform,quantizationandentropycodingform.Bit
Streampartoftheorganizationincludezoning,codeblocks,layersandpackagesorganization.
JPEG2000formatimagecompressionratiocanbebasedonthecurrentJPEG
Furtherincreasedby10%to30%,andthecompressedimageisevenmoredelicatesmooth.For
ThecurrentJPEGstandard,inthesamecompressedstreamcannotprovidelossyand
Losslesscompression,whileinJPEG2000system,byselectingtheparameters,beabletoimage
Forlossyandlosslesscompression.NowthenetworkisbasedonJPEGimagedownload
"Block"transmission,whiletheJPEG2000imageformatsupportforprogressivetransmission,whichusethe
Householdsdonotreceivetheentireimagecompressionbitstream.SinceJPEG2000useswavelettechnology
Surgerymayberandomaccesstosomeimageregionofinterest(ROI)ofthecompressedstream,right
Compressedimagedatatransmission,filteringandotheroperations[4].
Figure1JPEG2000compressionanddecompressionoftheoverallprocess
2.2JPEG2000compressionprospects
JPEG2000standardappliestoavarietyofimagecompressioncoding.Itsapplicationfield
WillincludetheInternet,fax,printing,remotesensing,mobilecommunications,medical,digitallibraries
Ande-commerce[5].JPEG2000imagecompressionstandardwillbecomethe21stcentury,themain
Flowstillimagecompressionstandard.
3WaveletImageCompression
3.1PrincipleofWaveletImageCompression
WaveletTransformforimagecodingbasicideaisthattheimageaccordingtoMallat
Towerfastwavelettransformalgorithmformulti-resolutiondecomposition.Thespecificprocessis:
First,theimagemulti-levelwaveletdecomposition,thentheamountofthewaveletcoefficientsofeachlayer
Andre-pairsofthequantizedcoefficientsencoded.Waveletimagecompressionisthecurrentimagecompression
Oneofthehotshrinkagehasbeenformedbasedonwavelettransformofinternationalcompressionstandards,suchasthe
MPEG-4standard,andasmentionedabovetheJPEG2000standard[2].
3.2WaveletImageCompressionStatusandProspects
Atpresentthethreehighestlevelsofwaveletimagecodingareembeddedwaveletzero-
TreeImageCoding(EZW),hierarchicaltreedistributionofthesampleimagecoding(SPIHT)and
Expandimagecompressioncoding(EBCOT).
(1)EZWcoder[6]
In1993,Shapirointroducedawavelet"zero-tree"concept,bydefining
POS,NEG,IZandZTRsymbolsarefourkindsofrecursivespatialwavelettreecoding,thereare
Effectivetoremovetheencodingofhigh-frequencycoefficients,whichgreatlyimprovedthecodingofwaveletcoefficients
Efficiency.Thisalgorithmisusedtoquantifyandembeddedprogressivecodingmode,thealgorithmco
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