python 填充图片，并将原图片以及垫之后的图片，并排显示成副区

Posted 2021-05-09

import numpy as np
def zero_pad(X, pad):
    """
    Pad with zeros all images of the dataset X. The padding is applied to the height and width of an image, 
    as illustrated in Figure 1.
    
    Argument:
    X -- python numpy array of shape (m, n_H, n_W, n_C) representing a batch of m images
    pad -- integer, amount of padding around each image on vertical and horizontal dimensions
    
    Returns:
    X_pad -- padded image of shape (m, n_H + 2*pad, n_W + 2*pad, n_C)
    """
    return np.pad(X, ((0, 0), (pad, pad), (pad, pad), (0, 0)), 'constant')

np.random.seed(1)
x = np.random.randn(4, 3, 3, 2) # (m, n_H, n_W, n_C) representing a batch of m images
x_pad = zero_pad(x, 2)
fig, axarr = plt.subplots(1, 2, figsize=(15, 10));
axarr[0].set_title('x');
axarr[0].imshow(x[0,:,:,0]);
axarr[1].set_title('x_pad');
axarr[1].imshow(x_pad[0,:,:,0]);

fig, axarr = plt.subplots(1, 2);
axarr[0].set_title('x');
axarr[0].imshow(x[0,:,:,0]);
axarr[1].set_title('x_pad');
axarr[1].imshow(x_pad[0,:,:,0]);