How to make a Gaussian filter in Matlab

Question

I have tried to make a Gaussian filter in Matlab without using imfilter() and fspecial(). I have tried this but result is not like the one I have w

Answer 1

here's an alternative:

Create the 2D-Gaussian:

  function f=gaussian2d(N,sigma)
  % N is grid size, sigma speaks for itself
 [x y]=meshgrid(round(-N/2):round(N/2), round(-N/2):round(N/2));
 f=exp(-x.^2/(2*sigma^2)-y.^2/(2*sigma^2));
 f=f./sum(f(:));

Filtered image, given your image is called Im:

 filtered_signal=conv2(Im,gaussian2d(N,sig),'same');

Here's some plots:

imagesc(gaussian2d(7,2.5))

 Im=rand(100);subplot(1,2,1);imagesc(Im)
 subplot(1,2,2);imagesc(conv2(Im,gaussian2d(7,2.5),'same'));