"""
Radial mean
============

This example shows how to do a radial mean with scikit-image.
"""

import numpy as np
import scipy as sp
import matplotlib.pyplot as plt

f = sp.datasets.face(gray=True)
sx, sy = f.shape
X, Y = np.ogrid[0:sx, 0:sy]


r = np.hypot(X - sx/2, Y - sy/2)

rbin = (20* r/r.max()).astype(int)
radial_mean = sp.ndimage.mean(f, labels=rbin, index=np.arange(1, rbin.max() +1))

plt.figure(figsize=(5, 5))
plt.axes([0, 0, 1, 1])
plt.imshow(rbin, cmap=plt.cm.nipy_spectral)
plt.axis('off')

plt.show()