基于小波與分形的圖像壓縮技術(shù)研究.pdf

1、學(xué)校代號：10536學(xué)號：fi2041051密級：長沙理工大學(xué)碩士學(xué)位論文基于小波與分形的圖像壓縮技術(shù)研究學(xué)位申請人姓名：昱險蜜導(dǎo)師姓名及職稱茲股瑾熬攫培養(yǎng)單位讓簋扭通籃皇互捏堂瞳專業(yè)名稱讓簋扭應(yīng)用拄盔～論文提交日期!!Q至2旦2目論文答辯日期答辯委員會主席章機應(yīng)AbstractTheprincipleoffractalimagecompressionisthatlocalselfsimilarityformaLocalIterated

2、FunctionSystemTheimagequality，compressionratioandcodespeedoffractaldecodedependonthesizeofchildblock。Ifthesizeofchildblockisbiggerthenthecompressionratioandcodespeedishigher，buttheimagequalityispoorerafterdecodingOntheco

3、ntrarythequalityoftheimageisbetterafterdecoding，butthecodespeedisslowerQuadtreesalgorithmcanmakethechildblockbiggerintheregionwhereithasgoodselfsimilarityOtherwise，quadtreesalgorithmmakesthechildblocksmaller。Thusthequadt

4、reesalgorithmcanensuregoodimagequantityoffractalcompressionafterdecodingTheevolutionalgorithmisarandomsearchalgorithmItisfasterthanmethodofexhaustionwhenwesearchthemostmatchedparentblockofachildblockinfractalimagecompres

5、sionThetwo—dimentionalgreylevelimageisdividedintothelowfrequencyareaandhighfrequencyareaafterthewavelettransform，andlow—frequencyareaconcentratesthemostofenergyoftheimagej丑thesmallareaandhighfrequencyareaspreadslittleene

6、rgyoftheimageinthewideareaTheprimitivelocalself—similarityintwodimentionalgreylevelimageisdestroiedafterwavelettransformButwaveletcoefficientsexistsselfsimilarityamongthelayeresinhighfrequencyareaSotheimagecanbecompresse

7、dbyfractalafterwavelettransformThispaperproposesanewstillimagecompressionalgorithmbasedonfractalandwaveletItusesdifferentalgorithmstOcompresswaveletcoefficientsbecauseofthedifferencesoftheenergydistributingbetweenlow—fre

8、quencyareaandhighfrequencyareaThewaveletcoefficientsinlowfrequencyareaaresaveddirectlyafterquantized；theselfsimilarityamonglayersformaLocalIteratedFunctionSystem，SOwaveletcoefficientsinhigh—frequencyareacanbecompressedby

9、fractalThenewalgorithmusesquadtreestodividethehighfrequencyareamorereasonablelyandraisequalityoftheimageafterdecoding；ThenewalgorithmUSeSevolvealgorithmtaisethematchspeedbetweenfatherblocksandchildblock；Thenewalgorithmus

10、ethevalidityscanofchildblocktoletfractalcodeonlyinthevalidregionwhichtheMSEisbiggerthan2，thevalidityscanmakethechildblockbecomesmallerbutitdon’tincreasethenumberofchildblock，itraisetheefficiencyoffractalcompressioninwave