interp = sp.interpolate.interp2d(x, y, image)
vinterp = np.vectorize(interp)
for r in (15, 30, 45):
    xcenter = len(x) / 2
ycenter = len(y) / 2
arclen = 2 * np.pi * r
angle = np.linspace(0, 2 * np.pi, arclen * 2, endpoint=False)
value = vinterp(xcenter + r * np.sin(angle), ycenter + r * np.cos(angle))
plt.plot(angle, value, label='r={}'.format(r))
plt.legend()
plt.show()
Take data from a circle in python