??? Attempted to access cmtx(1.00024,1); index must be a positive integer or logical.

hello sir, I am working with a image . and i am applying entropic thresholding on the image ,and i get the error. how to solve this error

    "??? Attempted to access cmtx(1.00024,1); index must be a positive integer or logical."
Error in ==> file1>GABOR_Callback at 809

     cmtx(fix(rt(m,n))+1,fix(rt(m,n+1))+1) = cmtx(rt(m,n)+1,rt(m+1,n+1)+1) + 1

here rt is my image

and my thresholding code is

[M,N] =size(rt);
cmtx = zeros(256,256);
for m = 1:M-1
  for n = 1:N-1        
     cmtx(rt(m,n)+1,rt(m,n+1)+1) = cmtx(rt(m,n)+1,rt(m+1,n+1)+1) + 1;
  end
end

scmtx = sum(cmtx(:)); prob = cmtx/scmtx;

emax = -100; for i=1:255

    probA = 0;
    probC = 0;

    subProbA = prob(1:i,1:i);
    probA = sum(subProbA(:));
    HA(i) = -0.5*(probA*log2(probA+0.0000001));

    subProbC = prob(i+1:256,i+1:256);
    probC = sum(subProbC(:));
    HC(i) = -0.5*(probC*log2(probC+0.0000001));

    e1(i) = HA(i) + HC(i); 
    if e1(i) >= emax
        emax = e1(i);
        tt1 = i;
    end
end

end

Answer 1

[David Sanchez]

your sentece:

cmtx(fix(rt(m,n))+1,fix(rt(m,n+1))+1) = cmtx(rt(m,n)+1,rt(m+1,n+1)+1) + 1

returns a value for

rt(m,n)+1 = 1.00024

you can only access integer values when dealing with matrices. Try to round the values of both rt(m,n)+1 and rt(m+1,n+1)+1 or modify your rt function in order to avoid decimals:

   round(rt(m,n)+1) = 1

[vidya]

sir..i cant change the values because,the values are the values from convoluted image and also i applied round function but it takes more time to run and all the values are zero..sir could u please help ..i am badly in need..is there any simple method where i can apply ENTROPIC THRESHOLDING

[Walter Roberson]

How do your construct rt ?

[vidya]

rt is constructed by convolution . my first image is rgb image and next i apply gabor filter on it ..after that i apply convolution on my image and that is my rt..now i apply entropic thresholding on my image

[vidya]

sir i solved the problem by using rt = fix(rt) and the i pass this rt into cmtx.b= but now i get a blank output with a small dot..i think this is because of the fix function.. and for the worst part even i remove fix function ..out put is same(a smalll dot) ...can u please temme what may the reason for this