title: Smoothing banding noise of scanned photos
body: <p>I am trying to filter this kind of banding noise on dark areas of scanned images. I have already removed pattern noise with FFT filtering and applied some median filter. All the bright parts of the images look great, but darker patches look like this:</p>
  <p><a href="https://i.stack.imgur.com/2KUtn.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2KUtn.jpg" alt="enter image description here" /></a></p>
  <p>Is there anything that can be done to smooth these patches without losing detail in the brighter ones ?</p>
  <p>Thanks.</p>