# import the necessary packages
from tensorflow.keras.layers import BatchNormalization
from tensorflow.keras.layers import Conv2D
from tensorflow.keras.layers import Conv2DTranspose
from tensorflow.keras.layers import LeakyReLU
from tensorflow.keras.layers import Activation
from tensorflow.keras.layers import Flatten
from tensorflow.keras.layers import Dense
from tensorflow.keras.layers import Reshape
from tensorflow.keras.layers import Input
from tensorflow.keras.models import Model
from tensorflow.keras import backend as K
import numpy as np
class ConvAutoencoder:
@staticmethod
def build(width, height, depth, filters=(32, 64), latentDim=16):
# initialize the input shape to be "channels last" along with
# the channels dimension itself
# channels dimension itself
inputShape = (height, width, depth)
chanDim = -1
# define the input to the encoder
inputs = Input(shape=inputShape)
x = inputs
# loop over the number of filters
for f in filters:
# apply a CONV =>RELU =>BN operation
x = Conv2D(f, (3, 3), strides=2, padding="same")(x)
x = LeakyReLU(alpha=0.2)(x)
x = BatchNormalization(axis=chanDim)(x)
# flatten the network and then construct our latent vector
volumeSize = K.int_shape(x)
x = Flatten()(x)
latent = Dense(latentDim)(x)
# build the encoder model
encoder = Model(inputs, latent, name="encoder")
# start building the decoder model which will accept the
# output of the encoder as its inputs
latentInputs = Input(shape=(latentDim,))
x = Dense(np.prod(volumeSize[1:]))(latentInputs)
x = Reshape((volumeSize[1], volumeSize[2], volumeSize[3]))(x)
# loop over our number of filters again, but this time in
# reverse order
for f in filters[::-1]:
# apply a CONV_TRANSPOSE =>RELU =>BN operation
x = Conv2DTranspose(f, (3, 3), strides=2, padding="same")(x)
x = LeakyReLU(alpha=0.2)(x)
x = BatchNormalization(axis=chanDim)(x)
# apply a single CONV_TRANSPOSE layer used to recover the
# original depth of the image
x = Conv2DTranspose(depth, (3, 3), padding="same")(x)
outputs = Activation("sigmoid")(x)
# build the decoder model
decoder = Model(latentInputs, outputs, name="decoder")
# our autoencoder is the encoder + decoder
autoencoder = Model(inputs, decoder(encoder(inputs)), name="autoencoder")
# return a 3-tuple of the encoder, decoder, and autoencoder
return (encoder, decoder, autoencoder)
# set the matplotlib backend so figures can be saved in the background
import matplotlib
matplotlib.use("Agg")
# import the necessary packages
from tensorflow.keras.optimizers import Adam
from tensorflow.keras.datasets import mnist
import matplotlib.pyplot as plt
import numpy as np
import argparse
import cv2
# construct the argument parse and parse the arguments
ap = argparse.ArgumentParser()
ap.add_argument("-s", "--samples", type=int, default=8, help="# number of samples to visualize when decoding")
ap.add_argument("-o", "--output", type=str, default="output.png", help="path to output visualization file")
ap.add_argument("-p", "--plot", type=str, default="plot.png", help="path to output plot file")
args = vars(ap.parse_args())
# initialize the number of epochs to train for and batch size
EPOCHS = 25
BS = 32
# load the MNIST dataset
print("[INFO] loading MNIST dataset...")
((trainX, _), (testX, _)) = mnist.load_data()
# add a channel dimension to every image in the dataset, then scale
# the pixel intensities to the range [0, 1]
trainX = np.expand_dims(trainX, axis=-1)
testX = np.expand_dims(testX, axis=-1)
trainX = trainX.astype("float32") / 255.0
testX = testX.astype("float32") / 255.0
# sample noise from a random normal distribution centered at 0.5 (since
# our images lie in the range [0, 1]) and a standard deviation of 0.5
trainNoise = np.random.normal(loc=0.5, scale=0.5, size=trainX.shape)
testNoise = np.random.normal(loc=0.5, scale=0.5, size=testX.shape)
trainXNoisy = np.clip(trainX + trainNoise, 0, 1)
testXNoisy = np.clip(testX + testNoise, 0, 1)
# construct our convolutional autoencoder
print("[INFO] building autoencoder...")
(encoder, decoder, autoencoder) = ConvAutoencoder.build(28, 28, 1)
opt = Adam(lr=1e-3)
autoencoder.compile(loss="mse", optimizer=opt)
# train the convolutional autoencoder
H = autoencoder.fit(trainXNoisy, trainX, validation_data=(testXNoisy, testX), epochs=EPOCHS, batch_size=BS)
# construct a plot that plots and saves the training history
N = np.arange(0, EPOCHS)
plt.style.use("ggplot")
plt.figure()
plt.plot(N, H.history["loss"], label="train_loss")
plt.plot(N, H.history["val_loss"], label="val_loss")
plt.title("Training Loss and Accuracy")
plt.xlabel("Epoch #")
plt.ylabel("Loss/Accuracy")
plt.legend(loc="lower left")
plt.savefig(args["plot"])
# use the convolutional autoencoder to make predictions on the
# testing images, then initialize our list of output images
print("[INFO] making predictions...")
decoded = autoencoder.predict(testXNoisy)
outputs = None
# loop over our number of output samples
for i in range(0, args["samples"]):
# grab the original image and reconstructed image
original = (testXNoisy[i] * 255).astype("uint8")
recon = (decoded[i] * 255).astype("uint8")
# stack the original and reconstructed image side-by-side
output = np.hstack([original, recon])
# if the outputs array is empty, initialize it as the current
# side-by-side image display
if outputs is None:
outputs = output
# otherwise, vertically stack the outputs
else:
outputs = np.vstack([outputs, output])
# save the outputs image to disk
cv2.imwrite(args["output"], outputs)
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