小波变换数字水印

1、 clear; load woman; I=X; type=db1; CA1,CH1,CV1,CD1=dwt2(I,type); C1=CH1 CV1 CD1; length1,width1=size(CA1); M1,N1=size(C1); T1=50; alpha=0.2; for counter2=1:1:N1 for counter1=1:1:M1 if(C1(counter1,counter2)T1) marked1(counter1,counter2)=randn(1,1); NEWC1(counter1,counter2)=double(C1(counter1,counter2

2、)+. alpha*abs(double(C1(counter1,counter2)*marked1(counter1,counter2); else marked1(counter1,counter2)=0; NEWC1(counter1,counter2)=double(C1(counter1,counter2); end; end;end; NEWCH1=NEWC1(1:length1,1:width1); NEWCV1=NEWC1(1:length1,width1+1:2*width1); NEWCD1=NEWC1(1:length1,2*width1+1:3*width1); R1=

3、double(idwt2(CA1,NEWCH1,NEWCV1,NEWCD1,type); watermark1=double(R1)-double(I); figure(1); subplot(1,2,1); image(I); axis(square); title(原始图像); subplot(1,2,2); imshow(R1/250); axis(square); title(Daubechies 小波变换后图像); figure(2); imshow(watermark1*1016); axis(square); title(水印图像); newmarked1=reshape(mar

4、ked1,M1*N1,1); T2=60; for counter2=1:1:N1 for counter1=1:1:M1 if(NEWC1(counter1,counter2)T2) NEWC1X(counter1,counter2)=NEWC1(counter1,counter2); else NEWC1X(counter1,counter2)=0; end; end; end; NEWC1X=reshape(NEWC1X,M1*N1,1); correlation1=zeros(1000,1); for corrcounter=1:1:1000 if(corrcounter=500) c

5、orrelation1(corrcounter,1)=NEWC1X*newmarked1/(M1*N1); end; end; originalthreshold=0; for counter2=1:1:N1 for counter1=1:1:M1 if(NEWC1(counter1,counter2)T2) originalthreshold=originalthreshold+abs(NEWC1(counter1,counter2); end; end; end; originalthreshold=originalthreshold*alpha/(2*M1*N1); corrcounter=1000; originalthresholdvector=ones(corrcounter,1)*originalthreshold; figure(3); plot(correlation1,-);