title: How to find and display a graph of mean square error as a function of quality factor using Matlab?
body: <p>Our teacher wants us to print at Matlab a graph that plots, in the <em>x axis</em>, the <strong>quality factor</strong>, and on the <em>y axis</em> the <strong>mean square error</strong>. The image is the known "lenna.jpg".</p>
  
  <p>I've searched and found how to find the mse, but I didn't find anything that helps me on how we find the quality factor.</p>
  
  <p>So, can you please tell me in Matlab code, how to find these 2 things and how to display them in a graph?</p>
  
  <p>Thanks in advance.</p>