text: from __future__ import print_function
  import mahotas.polygon
  from pylab import imshow, show
  import numpy as np
  from mahotas.features import surf
  
  f = np.zeros((1024,1024))
  Y,X = np.indices(f.shape)
  Y -= 768
  X -= 768
  f += 120*np.exp(-Y**2/2048.-X**2/480.)
  Y += 512
  X += 512
  rho = .7
  f += 120*np.exp(-1./( 2*(1-rho**2)) *( Y**2/32/32.+X**2/24/24. + 2*rho*X*Y/32./24.))
  fi = surf.integral(f.copy())
  spoints = surf.surf(f, 6, 24, 1)
  
  f2 = surf.show_surf(f, spoints)
  imshow(f2)
  show()
  