Chapter 51
DeepDream
NotebookPython 319 cells
This is a companion notebook for the book Deep Learning with Python, Second Edition. For readability, it only contains runnable code blocks and section titles, and omits everything else in the book: text paragraphs, figures, and pseudocode.
If you want to be able to follow what's going on, I recommend reading the notebook side by side with your copy of the book.
This notebook was generated for TensorFlow 2.6.
DeepDream
Implementing DeepDream in Keras
Fetching the test image
In [0]python · cell 5
python
from tensorflow import keras
import matplotlib.pyplot as plt
base_image_path = keras.utils.get_file(
"coast.jpg", origin="https://img-datasets.s3.amazonaws.com/coast.jpg")
plt.axis("off")
plt.imshow(keras.utils.load_img(base_image_path))Instantiating a pretrained InceptionV3 model
In [0]python · cell 7
python
from tensorflow.keras.applications import inception_v3
model = inception_v3.InceptionV3(weights="imagenet", include_top=False)Configuring the contribution of each layer to the DeepDream loss
In [0]python · cell 9
python
layer_settings = {
"mixed4": 1.0,
"mixed5": 1.5,
"mixed6": 2.0,
"mixed7": 2.5,
}
outputs_dict = dict(
[
(layer.name, layer.output)
for layer in [model.get_layer(name) for name in layer_settings.keys()]
]
)
feature_extractor = keras.Model(inputs=model.inputs, outputs=outputs_dict)The DeepDream loss
In [0]python · cell 11
python
def compute_loss(input_image):
features = feature_extractor(input_image)
loss = tf.zeros(shape=())
for name in features.keys():
coeff = layer_settings[name]
activation = features[name]
loss += coeff * tf.reduce_mean(tf.square(activation[:, 2:-2, 2:-2, :]))
return lossThe DeepDream gradient ascent process
In [0]python · cell 13
python
import tensorflow as tf
@tf.function
def gradient_ascent_step(image, learning_rate):
with tf.GradientTape() as tape:
tape.watch(image)
loss = compute_loss(image)
grads = tape.gradient(loss, image)
grads = tf.math.l2_normalize(grads)
image += learning_rate * grads
return loss, image
def gradient_ascent_loop(image, iterations, learning_rate, max_loss=None):
for i in range(iterations):
loss, image = gradient_ascent_step(image, learning_rate)
if max_loss is not None and loss > max_loss:
break
print(f"... Loss value at step {i}: {loss:.2f}")
return imageIn [0]python · cell 14
python
step = 20.
num_octave = 3
octave_scale = 1.4
iterations = 30
max_loss = 15.Image processing utilities
In [0]python · cell 16
python
import numpy as np
def preprocess_image(image_path):
img = keras.utils.load_img(image_path)
img = keras.utils.img_to_array(img)
img = np.expand_dims(img, axis=0)
img = keras.applications.inception_v3.preprocess_input(img)
return img
def deprocess_image(img):
img = img.reshape((img.shape[1], img.shape[2], 3))
img /= 2.0
img += 0.5
img *= 255.
img = np.clip(img, 0, 255).astype("uint8")
return imgRunning gradient ascent over multiple successive "octaves"
In [0]python · cell 18
python
original_img = preprocess_image(base_image_path)
original_shape = original_img.shape[1:3]
successive_shapes = [original_shape]
for i in range(1, num_octave):
shape = tuple([int(dim / (octave_scale ** i)) for dim in original_shape])
successive_shapes.append(shape)
successive_shapes = successive_shapes[::-1]
shrunk_original_img = tf.image.resize(original_img, successive_shapes[0])
img = tf.identity(original_img)
for i, shape in enumerate(successive_shapes):
print(f"Processing octave {i} with shape {shape}")
img = tf.image.resize(img, shape)
img = gradient_ascent_loop(
img, iterations=iterations, learning_rate=step, max_loss=max_loss
)
upscaled_shrunk_original_img = tf.image.resize(shrunk_original_img, shape)
same_size_original = tf.image.resize(original_img, shape)
lost_detail = same_size_original - upscaled_shrunk_original_img
img += lost_detail
shrunk_original_img = tf.image.resize(original_img, shape)
keras.utils.save_img("dream.png", deprocess_image(img.numpy()))