This is just another application of the autoencoder to denoise images. (This was not discussed in the paper that this work originated from)
The following code is a mere rearrangement of the code from the great tutorial below: https://blog.keras.io/building-autoencoders-in-keras.html
In [1]:
from keras.datasets import mnist
import numpy as np
(x_train, _), (x_test, _) = mnist.load_data()
x_train = x_train.astype('float32') / 255.
x_test = x_test.astype('float32') / 255.
x_train = np.reshape(x_train, (len(x_train), 28, 28, 1)) # adapt this if using `channels_first` image data format
x_test = np.reshape(x_test, (len(x_test), 28, 28, 1)) # adapt this if using `channels_first` image data format
noise_factor = 0.5
x_train_noisy = x_train + noise_factor * np.random.normal(loc=0.0, scale=1.0, size=x_train.shape)
x_test_noisy = x_test + noise_factor * np.random.normal(loc=0.0, scale=1.0, size=x_test.shape)
x_train_noisy = np.clip(x_train_noisy, 0., 1.)
x_test_noisy = np.clip(x_test_noisy, 0., 1.)
In [2]:
import matplotlib.pyplot as plt
n = 10
plt.figure(figsize=(20, 2))
for i in range(n):
which = np.random.randint(1, len(x_test[0]))
ax = plt.subplot(1, n, i + 1)
plt.imshow(x_test_noisy[which].reshape(28, 28))
plt.gray()
ax.get_xaxis().set_visible(False)
ax.get_yaxis().set_visible(False)
plt.show()
In [3]:
from keras.layers import Input, Dense, Conv2D, MaxPooling2D, UpSampling2D
from keras.models import Model
input_img = Input(shape=(28, 28, 1)) # adapt this if using `channels_first` image data format
x = Conv2D(32, (3, 3), activation='relu', padding='same')(input_img)
x = MaxPooling2D((2, 2), padding='same')(x)
x = Conv2D(32, (3, 3), activation='relu', padding='same')(x)
encoded = MaxPooling2D((2, 2), padding='same')(x)
# at this point the representation is (7, 7, 32)
x = Conv2D(32, (3, 3), activation='relu', padding='same')(encoded)
x = UpSampling2D((2, 2))(x)
x = Conv2D(32, (3, 3), activation='relu', padding='same')(x)
x = UpSampling2D((2, 2))(x)
decoded = Conv2D(1, (3, 3), activation='sigmoid', padding='same')(x)
autoencoder = Model(input_img, decoded)
autoencoder.compile(optimizer='adadelta', loss='binary_crossentropy')
In [4]:
autoencoder.fit(x_train_noisy, x_train,
epochs=30,
batch_size=128,
shuffle=True,
validation_data=(x_test_noisy, x_test))
Out[4]:
In [7]:
decoded_imgs = autoencoder.predict(x_test_noisy)
n = 10 # how many digits we will display
plt.figure(figsize=(20, 4))
for i in range(n):
which = np.random.randint(1, len(x_test_noisy[0]))
# display original
ax = plt.subplot(2, n, i + 1)
plt.imshow(x_test_noisy[which].reshape(28, 28))
plt.gray()
ax.get_xaxis().set_visible(False)
ax.get_yaxis().set_visible(False)
# display reconstruction
ax = plt.subplot(2, n, i + 1 + n)
plt.imshow(decoded_imgs[which].reshape(28, 28))
plt.gray()
ax.get_xaxis().set_visible(False)
ax.get_yaxis().set_visible(False)
plt.show()
In [8]:
autoencoder.save('DenoisingAutoencoder_ep30_val_loss0.0977')