title: How do I create and apply a Gaussian filter in MATLAB without using fspecial, imfilter or conv2?
body: <p>I have the following code in MATLAB:</p>
  
  <pre><code>I=imread(image);
  h=fspecial('gaussian',si,sigma);
  I=im2double(I);
  I=imfilter(I,h,'conv');
  figure,imagesc(I),impixelinfo,title('Original Image after Convolving with gaussian'),colormap('gray');
  </code></pre>
  
  <p>How can I define and apply a Gaussian filter to an image without <code>imfilter</code>, <code>fspecial</code> and <code>conv2</code>?</p>