error + matrix dimension must agree

I got error -- Error using + Matrix dimensions must agree.

on this code. Please help me

    a=sign(X(ind1)).*(abs(X(ind1))-T);
    b=abs(X);
    c=plus(a,b);

Answer 1

[Mischa Kim]

Nik, X and T need to be same-sized vectors unless T is a scalar.

What are you trying to do in

 a = sign(X(ind1)).*(abs(X(ind1))-T);

especially w.r.t. T?

[Nik]

i'm trying to add the hard threshold with soft threshold value. the original hard threshold func is:

function op=hthresh(X,T);

ind=find(abs(X)<=T);
    X(ind)=0;
    op=X;

and the soft threshold is:

function op=sthresh(X,T);
 ind=find(abs(X)<=T);
    ind1=find(abs(X)>T);
    X(ind)=0;
    X(ind1)=sign(X(ind1)).*(abs(X(ind1))-T);
    op=X;

now, im trying to get the average of absolute value of this 2 function:

function op=avthresh(X,T);

      a=sign(X(ind1)).*(abs(X(ind1))-T);
      b=abs(X);
      c=plus(a,b);
      d= abs(c);
      X(ind1)= d/2;
      op=X;

which I got error matrix dimension must agree.

Then, I change it to this one, it works but then the image and PSNR value is very bad..

   function op=avthresh(X,T); 
   a=sign(X(ind1)).*(abs(X(ind1))-T);
      b=numel(a);
      c=abs(X);
      d=numel(c);
      e=plus(b,d);
      f=abs(e/2);
      X(ind1)=f;
      op=X;

seek for your advice.. tq in advance

[Mischa Kim]

What are the sizes of X and T? Is T a scalar?

[Nik]

Sir Mischa, T is:

M=size(pic,1)^2;
T=sig*sqrt(2*log(M));

while X is the wavelet coefficient value. TQVM.