import numpy as np def get_demo_image(): # prepare image delta = 0.5 extent = (-3,4,-4,3) x = np.arange(-3.0, 4.001, delta) y = np.arange(-4.0, 3.001, delta) X, Y = np.meshgrid(x, y) import matplotlib.mlab as mlab Z1 = mlab.bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0) Z2 = mlab.bivariate_normal(X, Y, 1.5, 0.5, 1, 1) Z = (Z1 - Z2) * 10 return Z, extent