Subscript indices must either be real positive integers or logicals. The error starts when I am doing smoothing of the scan. However, I need positive and negative integer since its for brain scanning. Is there a method to solve this program?

% PREPARATION OF DATA FOR CLUSTERING ANALYSIS

%Creating a copy of the original dataset

scan = X;

mn = var(scan,0,3);

imagesc(mn);

%STEP 1: Normalization

A = A*-1;

scan = scan+A;

[m n p] = size(scan);

% Median Filter

for p = 1:180,

I = X(:,:,p);

smooth(:,:,p) = medfilt2(I,[m n]);

end

scan =smooth(I);

scan = reshape(smooth,m*n,p);

[KSSV]

Without knowing data, and the error line it would be tough to help you. I suspect you got error here scan =smooth(I); You are sending matrix I inside smooth, I doesn't have all positive integers, so error popped.

[Walter Roberson]

And you overwrite scan on the next line so there is no reason to have the line anyhow.