Question

function X=extractDWT(x_train,startS,endS,wStep,wRange)
% x_train = input signal
% startS   = from second
% endS     = end second
% wStep   = overlapping
% wRange = window size
FS=128;

N=size(x_train,3);
sz=floor((endS-(startS+wRange))/wStep)+1;
X=zeros(sz*140,2);
cn=0;
for i=1:N
   
    for sig=startS:wStep:endS-wRange
       
        sW=sig*FS+1;
        eW=(sig+wRange)*FS;
       
        C3Sig=x_train(sW:eW,1,i);
        C4Sig=x_train(sW:eW,3,i);
       
        waveletFunction = 'db4';
        waveletLevel=3;
        [wCoe,L] = wavedec(C3Sig,waveletLevel,waveletFunction);
        C3D3 = detcoef(wCoe,L,3);   % Mu
       
       
        [wCoe,L] = wavedec(C4Sig,waveletLevel,waveletFunction);
        C4D3 = detcoef(wCoe,L,3); % Mu
       
        cn=cn+1;
        % Mean of the absolute values
        X(cn,1)=sum(C3D3.^2)/numel(C3D3);
        X(cn,2)=sum(C4D3.^2)/numel(C4D3);
    end
end

end

Need code explanation for above code?

Answer 1

`Hey,

Note: Brother if you have any queries related the answer please do comment. I would be very happy to resolve all your queries.

Below is your code with full comments at each line for explaination

function X=extractDWT(x_train,startS,endS,wStep,wRange)%A function with name extractDWT and several inputs
% x_train = input signal
% startS = from second
% endS = end second
% wStep = overlapping
% wRange = window size
FS=128;%define and initialize Fs as 128

N=size(x_train,3);%number of elements in 3rd dimension of input signal x_train matrix
sz=floor((endS-(startS+wRange))/wStep)+1;%define and initialize sz as the greatest integer less than the ((endS-(startS+wRange))/wStep)+1
X=zeros(sz*140,2);%define X as the zeros matrix with sz*140 rows and 2 columns
cn=0;%initialize cn as 0
for i=1:N% a loop to go from 1 to N

for sig=startS:wStep:endS-wRange% a loop with sig values from startS to endS-wRange in steps of wStep

sW=sig*FS+1;%define sW as sig*Fs+1
eW=(sig+wRange)*FS;%define eW as (sig+wRange)*FS

C3Sig=x_train(sW:eW,1,i);%define C3Sig as the matrix with elements of x_train matrix from sW to eW rows, 1st column and ith 3 dimensional element
C4Sig=x_train(sW:eW,3,i);%define C4Sig as the matrix with elements of x_train matrix from sW to eW rows, 3rd column and ith 3 dimensional element

waveletFunction = 'db4';%define waveletFunction as the char array with characters db4
waveletLevel=3;%define waveletLevel as 3
[wCoe,L] = wavedec(C3Sig,waveletLevel,waveletFunction);%Find the 1-D wavelet decomposition wCoe and L
C3D3 = detcoef(wCoe,L,3); % Mu, finds the wavelet analysis


[wCoe,L] = wavedec(C4Sig,waveletLevel,waveletFunction);%Find the 1-D wavelet decomposition wCoe and L
C4D3 = detcoef(wCoe,L,3); % Mu, finds the wavelet analysis

cn=cn+1;%increment cn by 1
% Mean of the absolute values
X(cn,1)=sum(C3D3.^2)/numel(C3D3);%assign the cn'th row and first column of X to a value as sum of squares of elements of C3D3 divided by length of C3D3
X(cn,2)=sum(C4D3.^2)/numel(C4D3);%assign the cn'th row and second column of X to a value as sum of squares of elements of C4D3 divided by length of C4D3
end
end

end

Kindly revert for any queries

Thanks.