title: How to get the Signal-to-Noise-Ratio from an image in Python?
body: <p>I am filtering an image and I would like to know the SNR. I tried with the scipy function  scipy.stats.signaltonoise() but I get an array of numbers and I don't really know what I am getting.</p>
  
  <p>Is there any other way to get te SNR of my image?</p>