def iter_occlusion(image, size=8):
occlusion = np.full((size * 5, size * 5, 1), [0.5], np.float32)
occlusion_center = np.full((size, size, 1), [0.5], np.float32)
occlusion_padding = size * 2
# print('padding...')
image_padded = np.pad(image, ( \
(occlusion_padding, occlusion_padding), (occlusion_padding, occlusion_padding), (0, 0) \
), 'constant', constant_values = 0.0)
for y in range(occlusion_padding, image.shape[0] + occlusion_padding, size):
for x in range(occlusion_padding, image.shape[1] + occlusion_padding, size):
tmp = image_padded.copy()
tmp[y - occlusion_padding:y + occlusion_center.shape[0] + occlusion_padding, \
x - occlusion_padding:x + occlusion_center.shape[1] + occlusion_padding] \
= occlusion
tmp[y:y + occlusion_center.shape[0], x:x + occlusion_center.shape[1]] = occlusion_center
yield x - occlusion_padding, y - occlusion_padding, \
tmp[occlusion_padding:tmp.shape[0] - occlusion_padding, occlusion_padding:tmp.shape[1] - occlusion_padding]
i = 23 # 例如
data = val_x[i]
correct_class = np.argmax(val_y[i])
# model.predict的输入向量
inp = data.reshape(1, 28, 28, 1)
# matplotlib imshow函数的图片
img = data.reshape(28, 28)
# 遮盖
img_size = img.shape[0]
occlusion_size = 4
print('occluding...')
heatmap = np.zeros((img_size, img_size), np.float32)
class_pixels = np.zeros((img_size, img_size), np.int16)
from collections import defaultdict
counters = defaultdict(int)
for n, (x, y, img_float) in enumerate(iter_occlusion(data, size=occlusion_size)):
X = img_float.reshape(1, 28, 28, 1)
out = model.predict(X)
#print('#{}: {} @ {} (correct class: {})'.format(n, np.argmax(out), np.amax(out), out[0][correct_class]))
#print('x {} - {} | y {} - {}'.format(x, x + occlusion_size, y, y + occlusion_size))
heatmap[y:y + occlusion_size, x:x + occlusion_size] = out[0][correct_class]
class_pixels[y:y + occlusion_size, x:x + occlusion_size] = np.argmax(out)
counters[np.argmax(out)] += 1