python - vectorize way of image downsampling

Question

I want to down sample image by 2.But is there a faster and vectorized way to implement this without using for loops?

import numpy as np
m, n = f.shape
h=np.zeros((m/2,n/2)
for i in range(m/2):
  for j in range(n/2):
    h[i,j] = f[2*i,2*j]

Answer 1

等待大神答复