Error in getting output

Question

kash 2012-12-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/57129-error-in-getting-output

    clc
    clear all
    close all
    [y,Fs,nbits] = wavread('bird.wav');
    [cA,cH,cL,cD] = dwt2(y,'haar');%wavelet decomposition
    C1=int16(cA*32768);C2=int16(cH*32768);%%%%convertibg to 16 bit
    [y1, Fs, nbits] = wavread('wov.wav');
    [sA,sH,sL,sD] = dwt2(y1,'haar');
    S1=max(min(round(2^13*sA),2^13),-2^13);%%%%%convertibg to 14 bit
    S2=max(min(round(2^13*sH),2^13),-2^13);
    Cw=C1;
    Sw=S1;
    %%%%%%applying threshold
    for i=1:length(Cw)
        if (Cw(i)<7 && Cw(i)>-7)
            Cw(i)=0;
        end
    end
    for i=1:length(Sw)
        if (Sw(i)<7 && Sw(i)>-7)
            Sw(i)=0;
        end
    end
    A=Cw;
    B=Sw;
    if length(A)<length(B)
        S=length(B)-length(A);
        S1=zeros(S,1);
        A=[A;S1];B;
    elseif length(A)>length(B)
        S=length(A)-length(B);
        S1=zeros(S,1);
        B=[B;S1];A;
    else
        A;B;
    end
    Cw=A;
    Sw=B;
    %%%%%SORTING
    [~,J] = sort(A);
    BSA = sort(B);
    J(J) = 1:length(A);
    BSA = BSA(J);
    [J1,ke] = ismember(BSA,Sw);
    key=ke;
    Ew=double(BSA)./double(Cw);
    Ew=ceil(Ew*100);
    Ew(~isfinite(Ew))=0;
    nn=16;
    n=15;
    Cw=double(Cw);
    Cw1 = dec2bin(mod(2^n+Cw,2^n));
    Ew1 = dec2bin(mod(2^5+Ew,2^5),5);
    %%%%%%%%%%%%%%%%%%%%%%EMBEDDED%%%%%%%%%%%%%%%%%%%%%%%
    n=[];
    CC = Cw1;
    DD = Ew1;
    n=11;
    CC(:,n:n+size(DD,2)-1)=DD ;
    CC=bin2dec(CC);
    X = idwt2(CC,cH,cL,cD,'haar');
    %%%%%%rescaling%%%%%%%%%
    mi=min(min(y));
    mx=max(max(y));
    B=nma_rescale(X,mi,mx)
    mat=X;
    matmin = mi;
    matmax = mx;
    newmat = 2 * (mat - matmin) ./ (matmax - matmin) - 1;
    subplot(3,1,1),plot(y);
    subplot(3,1,2),plot(B);

In the above code after embeddeding the secret signal with the host signal,the embeeded image is not a signal wave

The process aove is speech stegnography,

please tell why the embedded signal is not a signal wave

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Answer 1

Image Analyst 2012-12-21

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/57129-error-in-getting-output#answer_69102

Well I suppose since the secret signal did not replace the target signal, but was combined with it in a special way, that neither signal is a sine wave nor has its original form anymore. Why did you think that it would remain a sine wave after combining with the host signal?

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Image Analyst 2012-12-21

编辑：Image Analyst 2012-12-21

I know that - none of the three signals ("secret," "host," and "embedded" which I guess is the output signal) are the same. But once the secret signal that is " to be embedded" actually GETS embedded into the host, the result will not look like either one. Explain this: ",the embeeded image is not a signal wave". What is "a signal wave"???? All three waveforms are signals so I don't know what you're talking about. And what image? I thought these were 1D sounds. BTW, I am not an expert in steganography. I'm not sure anyone here is, at least not that I recall. Please try to carefully rephrase your question using the most accurate terminology you can.

kash 2012-12-21