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1、小波去噪举例MATLAB中用wnoise函数测试去噪算法sqrt_snr=3;init=231434;[x,xn]=wnoise(3,11,sqrt_snr,init);%加噪，信噪比为3subplot(3,2,1),plot(x)title('originaltestfunction')subplot(3,2,2),plot(xn)title('noisedfunction')lev=5;xd=wden(x,'heursure','s','one',lev,'sym8');%利用小波对一维信号进行降噪,XD为降噪后的%信号，CXD，LXD为XD的小波分解结构%'s'or'h'决定阈
2、值的使用方式，SCAL决定阈值是%否随噪声变化：'one'不调整，'sln'对第一层系%数的层噪声分别进行估计和调整；'mln'对各层%系数的层噪声分别进行估计和调整；subplot(3,2,3),plot(xd)title('Onede-noisedfunction')xd=wden(x,'heursure','s','sln',lev,'sym8');subplot(3,2,4),plot(xd)title('Slnde-noisedfunction')xd=wden(x,'sqtwolog','s','sln',lev,'sym8');%固定阈值选择算法去噪subplot(3,
3、2,5),plot(xd)title('Sqtwologde-noisedfunction')[c,l]=wavedec(x,lev,'sym8');subplot(3,2,6),plot(xd)title('CLde-noisedfunction')otherstaffoftheCentre.Duringthewar,ZhuwastransferredbacktoJiangxi,andDirectorofthenewOfficeinJingdezhen,JiangxiCommitteeSecretary.Startingin1939servedasrecorderoftheWest
4、NorthOrganization,SecretaryoftheSpecialCommitteeAfterthevictoryofthelongMarch,hehasbeentheNorthwestOfficeoftheFederationofStateenterprisesMinister,ShenmufuguSARmissions,DirectorofNingxiaCountypartyCommitteeSecretaryandrecorderoftheCountypartyCommitteeSecretary,MinistersandMATLAB中图像噪声处理举例loadsin
5、sin;colormap('default');subplot(1,3,1),image(X);title('originalimage');axis('square');init=231434;randn('seed',init);X=X+18*randn(size(X));%产生噪声信号subplot(1,3,2),image(x);title('noisedimage');axis('square');[thr,sorh,keepapp]=ddencmp('den','wv',x);%自动生成小波去躁或压缩的阈值选择方案，也%就是寻找默认值[xc,cxc,lxc,perf0,p
6、erfl2]=wdencmp('gbl',x,'sym4',2,thr,sorh,keepapp);%使用全局阈值进行%图象降噪subplot(1,3,3),image(xc);title('denoisedimage');axis('square')otherstaffoftheCentre.Duringthewar,ZhuwastransferredbacktoJiangxi,andDirectorofthenewOfficeinJingdezhen,JiangxiCommitteeSecretary.Startingin1939servedasrecorderoftheWest
7、NorthOrganization,SecretaryoftheSpecialCommitteeAfterthevictoryofthelongMarch,hehasbeentheNorthwestOfficeoftheFederationofStateenterprisesMinister,ShenmufuguSARmissions,DirectorofNingxiaCountypartyCommitteeSecretaryandrecorderofth
