text: from PIL import Image
  from numpy import *
  from pylab import *
  
  fname = "C:\\skunkworx\\Area52\\home\\6008895\dev\\bitbucket\\me-ml\\computervision\\jesolem-PCV-790b64d\\data\\empire.jpg"
  
  figure()
  im = array(Image.open(fname).convert("L"))
  print int(im.min()), int(im.max())
  gray()
  title("grayscale")
  imshow(im)
  
  figure()
  im2 = 255 - im
  print int(im2.min()), int(im2.max())
  title("inverted")
  imshow(im2)
  
  figure()
  im3 = (100.0/255) * im + 100
  print int(im3.min()), int(im3.max())
  title("clamped: 100...200")
  imshow(im3)
  
  figure()
  im4 = 255.0 * (im/255.0)**2
  print int(im4.min()), int(im4.max())
  title("squared")
  imshow(im4)
  
  show()