当使用Keras实现InfoGAN模型生成具有可控因素的手写数字图像时,需要按照以下步骤进行操作。
首先,导入所需的库和模块:
from keras.layers import Input, Dense, Reshape, Flatten, Dropout, multiply, concatenate
from keras.layers.advanced_activations import LeakyReLU
from keras.layers.convolutional import UpSampling2D, Conv2D
from keras.models import Sequential, Model
from keras.optimizers import Adam
from keras.datasets import mnist
import numpy as np
import matplotlib.pyplot as plt
接下来,定义生成器模型和判别器模型:
def build_generator(latent_dim, num_classes):
model = Sequential()
model.add(Dense(128 * 7 * 7, activation="relu", input_dim=latent_dim))
model.add(Reshape((7, 7, 128)))
model.add(UpSampling2D())
model.add(Conv2D(128, kernel_size=3, padding="same"))
model.add(BatchNormalization(momentum=0.8))
model.add(Activation("relu"))
model.add(UpSampling2D())
model.add(Conv2D(64, kernel_size=3, padding="same"))
model.add(BatchNormalization(momentum=0.8))
model.add(Activation("relu"))
model.add(Conv2D(1, kernel_size=3, padding="same"))
model.add(Activation("tanh"))
model.summary()
noise = Input(shape=(latent_dim,))
label = Input(shape=(num_classes,))
img = model(noise)
return Model([noise, label], img)
def build_discriminator(img_shape, num_classes):
model = Sequential()
model.add(Conv2D(32, kernel_size=3, strides=2, input_shape=img_shape, padding="same"))
model.add(LeakyReLU(alpha=0.2))
model.add(Dropout(0.25))
model.add(Conv2D(64, kernel_size=3, strides=2, padding="same"))
model.add(ZeroPadding2D(padding=((0, 1), (0, 1))))
model.add(LeakyReLU(alpha=0.2))
model.add(Dropout(0.25))
model.add(BatchNormalization(momentum=0.8))
model.add(Conv2D(128, kernel_size=3, strides=2, padding="same"))
model.add(LeakyReLU(alpha=0.2))
model.add(Dropout(0.25))
model.add(BatchNormalization(momentum=0.8))
model.add(Conv2D(256, kernel_size=3, strides=1, padding="same"))
model.add(LeakyReLU(alpha=0.2))
model.add(Dropout(0.25))
model.add(Flatten())
model.summary()
img = Input(shape=img_shape)
features = model(img)
validity = Dense(1, activation='sigmoid')(features)
label = Dense(num_classes, activation='softmax')(features)
return Model(img, [validity, label])
然后,定义InfoGAN模型:
def build_infogan(generator, discriminator, latent_dim, num_classes):
generator_input = Input(shape=(latent_dim,))
generator_label = Input(shape=(num_classes,))
generator_output = generator([generator_input, generator_label])
discriminator_output, discriminator_label = discriminator(generator_output)
return Model([generator_input, generator_label], [discriminator_output, discriminator_label, generator_output])
接下来,加载MNIST数据集并进行预处理:
(X_train, y_train), (_, _) = mnist.load_data()
X_train = X_train / 127.5 - 1.
X_train = np.expand_dims(X_train, axis=3)
num_classes = 10
y_train = y_train.reshape(-1, 1)
y_train = np.eye(num_classes)[y_train]
定义一些超参数:
img_shape = (28, 28, 1)
latent_dim = 62
epochs = 20000
batch_size = 128
sample_interval = 1000
然后,编译生成器、判别器和InfoGAN模型:
generator = build_generator(latent_dim, num_classes)
discriminator = build_discriminator(img_shape, num_classes)
infogan = build_infogan(generator, discriminator, latent_dim, num_classes)
discriminator.compile(loss=['binary_crossentropy', 'categorical_crossentropy'],
loss_weights=[1, 1],
optimizer=Adam(0.0002, 0.5))
infogan.compile(loss=['binary_crossentropy', 'categorical_crossentropy', 'mse'],
loss_weights=[1, 1, 0.1],
optimizer=Adam(0.0002, 0.5))
接下来,定义训练过程:
for epoch in range(epochs):
# ---------------------
# 训练判别器
# ---------------------
# 从训练集中随机选择一批图像和标签
idx = np.random.randint(0, X_train.shape[0], batch_size)
real_imgs = X_train[idx]
labels = y_train[idx]
# 生成一批噪声数据和随机标签
noise = np.random.normal(0, 1, (batch_size, latent_dim))
sampled_labels = np.random.randint(0, num_classes, (batch_size, 1))
sampled_labels = np.eye(num_classes)[sampled_labels]
# 使用生成器生成一批假图像
gen_imgs = generator.predict([noise, sampled_labels])
# 训练判别器
d_loss_real = discriminator.train_on_batch(real_imgs, [np.ones((batch_size, 1)), labels])
d_loss_fake = discriminator.train_on_batch(gen_imgs, [np.zeros((batch_size, 1)), sampled_labels])
d_loss = 0.5 * np.add(d_loss_real, d_loss_fake)
# ---------------------
# 训练生成器和InfoGAN
# ---------------------
# 生成一批噪声数据和随机标签
noise = np.random.normal(0, 1, (batch_size, latent_dim))
sampled_labels = np.random.randint(0, num_classes, (batch_size, 1))
sampled_labels = np.eye(num_classes)[sampled_labels]
# 训练生成器和InfoGAN
g_loss = infogan.train_on_batch([noise, sampled_labels], [np.ones((batch_size, 1)), sampled_labels, noise])
# 打印损失值
print("%d [D loss: %f, acc: %.2f%%] [G loss: %f]" % (epoch, d_loss[0], 100 * d_loss[1], g_loss[0]))
# 每隔一段时间保存并输出生成的图像样本
if epoch % sample_interval == 0:
r, c = 10, 10
noise = np.random.normal(0, 1, (r * c, latent_dim))
sampled_labels = np.array([num for _ in range(r) for num in range(c)])
sampled_labels = np.eye(num_classes)[sampled_labels]
gen_imgs = generator.predict([noise, sampled_labels])
gen_imgs = 0.5 * gen_imgs + 0.5
fig, axs = plt.subplots(r, c)
cnt = 0
for i in range(r):
for j in range(c):
axs[i, j].imshow(gen_imgs[cnt, :, :, 0], cmap='gray')
axs[i, j].axis('off')
cnt += 1
plt.show()
plt.close()
最后,运行训练过程:
infogan.fit([X_train, y_train], [np.ones((X_train.shape[0], 1)), y_train, X_train],
epochs=epochs,
batch_size=batch_size,
sample_interval=sample_interval)
这是一个简单的使用Keras实现InfoGAN模型生成具有可控因素的手写数字图像的示例。请注意,这只是一个基础的实现,您可以根据需要进行修改和改进。