title: Filtered BackProjection Matlab
body: <p>I have already implemented the code for BackProjection and it works.
  Now I have to implement the code for the filtered version, using first ramlak filter and then hamming window.
  My sinogram has dimension 144x180.
  My idea is </p>
  
  <pre><code>filter=zeros(1,144)';
  
  filter(1:73)=[0:1/72:1];
  
  filter(74:end)=[1-1/72:-1/72:1/72];
  </code></pre>
  
  <p>in order to have an filter like this <a href="https://i.stack.imgur.com/HXyiO.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HXyiO.jpg" alt="enter image description here"></a></p>
  
  <p>and then for each projection s </p>
  
  <pre><code>filtered_proj=fft(s).*filter;
  proj=real(ifft(filtered_proj));
  </code></pre>
  
  <p>and then performing the backprojection algorithm</p>
  
  <p>Could you please tell me if it is correct?</p>
  
  <p>Thank you</p>