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function [a,b,c,d]=dbdec2(x,N) 
%dbdec2  2-D Daubchies decompose  
%[a b c d]=dbdec2(x,N) 
 
rhcoef=dbaux(N); 
sx=size(x); 
%extention matrix size 
ex=ex_mat(x,N); 
 
%calculate the db coef  
[hcoef,gcoef]=rh2g(rhcoef); 
lhcoef=length(hcoef); 
 
%db transform 
lex=size(ex); 
lrout=sx(1)+2*(N-1); 
lcout=sx(2)+2*(N-1); 
if sx(1)==1   
    %1-D 
    cah=conv2(ex,hcoef)*sqrt(2); 
    a=cah(1,lhcoef:2:lhcoef+lcout-1); 
    cbh=conv2(ex,gcoef)*sqrt(2); 
    b=cbh(1,lhcoef:2:lhcoef+lcout-1); 
else  
    %2-D 
    cah=conv2(ex,hcoef)*sqrt(2); 
    ca=(conv2(cah',hcoef))'*sqrt(2); 
    a=ca(lhcoef:2:lhcoef+lrout-1,lhcoef:2:lhcoef+lcout-1); 
    cbh=conv2(ex,gcoef)*sqrt(2); 
    cb=(conv2(cah',gcoef))'*sqrt(2); 
    b=cb(lhcoef:2:lhcoef+lrout-1,lhcoef:2:lhcoef+lcout-1); 
    cc=(conv2(cbh',hcoef))'*sqrt(2); 
    c=cc(lhcoef:2:lhcoef+lrout-1,lhcoef:2:lhcoef+lcout-1); 
    cd=(conv2(cbh',gcoef))'*sqrt(2); 
    d=cd(lhcoef:2:lhcoef+lrout-1,lhcoef:2:lhcoef+lcout-1); 
end 
 
%-----------------------------------------------------% 
% Internal Function(s) 
%-----------------------------------------------------% 
function a=ex_mat(c,N) 
sx=size(c); 
lf=2*(N-1); 
dlf=2*lf; 
if N>1 
    if sx(1)==1 
        a=exh(c,N); 
        if mod(sx(2),2) 
            a(sx(2)+dlf+1)=a(sx(2)); 
        end 
    else 
        for i=1:sx(1) 
            tempa(i,:)=exh(c(i,:),N); 
        end 
        for j=1:sx(2)+dlf 
            a(:,j)=(exh(tempa(:,j)',N))'; 
        end 
        if mod(sx(1),2) 
           a(sx(1)+dlf+1,:)=a(sx(1),:); 
        end 
        if mod(sx(2),2) 
            a(:,sx(2)+dlf+1)=a(:,sx(2)); 
        end 
    end 
else 
    a=c; 
    if sx(1)==1 
        if mod(sx(2),2) 
            a(sx(2)+1)=a(sx(2)); 
        end 
    else 
        if mod(sx(1),2) 
            a(sx(1)+1,:)=a(sx(1),:); 
        end 
        if mod(sx(2),2) 
            a(:,sx(2)+1)=a(:,sx(2)); 
        end 
    end 
end 
%-----------------------------------------------------% 
% Internal Function(s) 
%-----------------------------------------------------% 
function a=exh(c,N) 
sx=size(c); 
lf=2*(N-1); 
dlf=2*lf; 
a(lf+1:lf+sx(2))=c; 
if lf<=sx(2) 
    a(lf+1:lf+sx(2))=c; 
    a(lf:-1:1)=c(1:lf); 
    a(sx(2)+lf+1:sx(2)+dlf)=c(sx(2):-1:sx(2)-lf+1);  
else 
    llf=lf; 
    rlf=lf; 
    for i=1:round(lf/sx(2)-0.5) 
        llf1=lf-i*sx(2); 
        rlf1=lf+i*sx(2); 
        a(llf:-1:llf1+1)=a(rlf+1:rlf1); 
        rlf2=lf+2*sx(2)-i*sx(2); 
        a(rlf1+1:rlf1+sx(2))=a(rlf2:-1:rlf2-sx(2)+1);    
        llf=llf1; 
        rlf=rlf1; 
    end 
    re=mod(lf,sx(2)); 
    if re 
        a(1:re)=a(rlf+re:-1:rlf+1); 
        a(dlf+sx(2)-re+1:dlf+sx(2))=a(rlf2-i*sx(2):-1:rlf2-i*sx(2)-re+1);                  
    end                
end 
%-----------------------------------------------------% 
% Internal Function(s) 
%-----------------------------------------------------% 
function [h,g]=rh2g(rh) 
%rh2g   Calculate the db coef  
 
for i=1:length(rh) 
    g(i)=(-1)^i*rh(i); 
end 
 
h=rh(length(rh):-1:1);