Denoising Autoencoders

What are Denoising Autoencoders?

Denoising Autoencoders are a type of autoencoder, which is a neural network-based unsupervised learning technique used for dimensionality reduction, feature learning, and data compression. Denoising autoencoders are specifically designed to remove noise from input data, and they learn to reconstruct clean data from noisy input data during training.

Why use Denoising Autoencoders?

Denoising Autoencoders have several applications, including:

  • Noise reduction: They can be used to remove noise from images, audio signals, and other data types.
  • Feature learning: Denoising autoencoders can learn useful features from noisy data, which can be used for downstream tasks such as classification or clustering.
  • Robustness: Training denoising autoencoders on noisy data can improve the model’s robustness and generalization to unseen data.

Example of using Denoising Autoencoders in Python with TensorFlow:

import numpy as np
import tensorflow as tf
from tensorflow.keras.datasets import mnist
from tensorflow.keras.layers import Dense, Input
from tensorflow.keras.models import Model

# Load the MNIST dataset
(x_train, _), (x_test, _) = mnist.load_data()
x_train, x_test = x_train / 255.0, x_test / 255.0

# Add noise to the training and test data
noise_factor = 0.5
x_train_noisy = x_train + noise_factor * np.random.normal(0, 1, x_train.shape)
x_test_noisy = x_test + noise_factor * np.random.normal(0, 1, x_test.shape)

# Define the autoencoder architecture
input_img = Input(shape=(28, 28))
x = tf.keras.layers.Flatten()(input_img)
x = Dense(128, activation='relu')(x)
x = Dense(64, activation='relu')(x)
x = Dense(128, activation='relu')(x)
x = Dense(28*28, activation='sigmoid')(x)
output_img = tf.keras.layers.Reshape((28, 28))(x)

autoencoder = Model(inputs=input_img, outputs=output_img)

# Compile the autoencoder
autoencoder.compile(optimizer='adam', loss='binary_crossentropy')

# Train the autoencoder, x_train, epochs=100, batch_size=256, validation_data=(x_test_noisy, x_test))

Additional resources on Denoising Autoencoders: