code: def sensitivity(imgs, bg=None):
      '''
      Extract pixel sensitivity from a set of homogeneously illuminated images
  
      This method is detailed in Section 5 of:
      ---
      K.Bedrich, M.Bokalic et al.:
      ELECTROLUMINESCENCE IMAGING OF PV DEVICES:
      ADVANCED FLAT FIELD CALIBRATION,2017
      ---
  
      '''
      bg = getBackground(bg)
      for n, i in enumerate(imgs):
          i = imread(i, dtype=float)
          i -= bg
          smooth = fastMean(median_filter(i, 3))
          i /= smooth
          if n == 0:
              out = i
          else:
              out += i
      out /= (n + 1)
      return ouf sensitivity(imgs, bg=None):
      '''
      Extract pixel sensitivity from a set of homogeneously illuminated images
  
      This method is detailed in Section 5 of:
      ---
      K.Bedrich, M.Bokalic et al.:
      ELECTROLUMINESCENCE IMAGING OF PV DEVICES:
      ADVANCED FLAT FIELD CALIBRATION,2017
      ---
  
      '''
      bg = getBackground(bg)
      for n, i in enumerate(imgs):
          i = imread(i, dtype=float)
          i -= bg
          smooth = fastMean(median_filter(i, 3))
          i /= smooth
          if n == 0:
              out = i
          else:
              out += i
      out /= (n + 1)
      return out
docs: Extract pixel sensitivity from a set of homogeneously illuminated images
  
      This method is detailed in Section 5 of:
      ---
      K.Bedrich, M.Bokalic et al.:
      ELECTROLUMINESCENCE IMAGING OF PV DEVICES:
      ADVANCED FLAT FIELD CALIBRATION,2017
      ---