keras实现DCGAN生成mnist原代码
算法原理
具体算法原理，在这里不再阐述，可以参考：
https://blog.****.net/stdcoutzyx/article/details/53872121
https://ask.julyedu.com/question/7681
基于keras的原代码
from keras.models import Sequential
from keras.layers import Dense
from keras.layers import Reshape
from keras.layers.core import Activation
from keras.layers.normalization import BatchNormalization
from keras.layers.convolutional import UpSampling2D
from keras.layers.convolutional import Conv2D, MaxPooling2D
from keras.layers.core import Flatten
from keras.optimizers import SGD
from keras.datasets import mnist
import numpy as np
from PIL import Image
import argparse
import math
def generator_model():
model = Sequential()
model.add(Dense(input_dim=100, output_dim=1024))
model.add(Activation('tanh'))
model.add(Dense(128*7*7))
model.add(BatchNormalization())
model.add(Activation('tanh'))
model.add(Reshape((7, 7, 128), input_shape=(128*7*7,)))
model.add(UpSampling2D(size=(2, 2)))
model.add(Conv2D(64, (5, 5), padding='same'))
model.add(Activation('tanh'))
model.add(UpSampling2D(size=(2, 2)))
model.add(Conv2D(1, (5, 5), padding='same'))
model.add(Activation('tanh'))
return model
def discriminator_model():
model = Sequential()
model.add(
Conv2D(64, (5, 5),
padding='same',
input_shape=(28, 28, 1))
)
model.add(Activation('tanh'))
model.add(MaxPooling2D(pool_size=(2, 2)))
model.add(Conv2D(128, (5, 5)))
model.add(Activation('tanh'))
model.add(MaxPooling2D(pool_size=(2, 2)))
model.add(Flatten())
model.add(Dense(1024))
model.add(Activation('tanh'))
model.add(Dense(1))
model.add(Activation('sigmoid'))
return model
def generator_containing_discriminator(g, d):
model = Sequential()
model.add(g)
d.trainable = False
model.add(d)
return model
def combine_images(generated_images):
num = generated_images.shape[0]
width = int(math.sqrt(num))
height = int(math.ceil(float(num)/width))
shape = generated_images.shape[1:3]
image = np.zeros((height*shape[0], width*shape[1]),
dtype=generated_images.dtype)
for index, img in enumerate(generated_images):
i = int(index/width)
j = index % width
image[i*shape[0]:(i+1)*shape[0], j*shape[1]:(j+1)*shape[1]] = \
img[:, :, 0]
return image
def train(BATCH_SIZE):
(X_train, y_train), (X_test, y_test) = mnist.load_data()
X_train = (X_train.astype(np.float32) - 127.5)/127.5
X_train = X_train[:, :, :, None]
X_test = X_test[:, :, :, None]
# X_train = X_train.reshape((X_train.shape, 1) + X_train.shape[1:])
d = discriminator_model()
g = generator_model()
d_on_g = generator_containing_discriminator(g, d)#使用判断器来监督生成器的训练
d_optim = SGD(lr=0.0005, momentum=0.9, nesterov=True)
g_optim = SGD(lr=0.0005, momentum=0.9, nesterov=True)
g.compile(loss='binary_crossentropy', optimizer="SGD")#只有生成器
d_on_g.compile(loss='binary_crossentropy', optimizer=g_optim)#编译生成器
d.trainable = True
d.compile(loss='binary_crossentropy', optimizer=d_optim)#只有判断器
for epoch in range(100):
print("Epoch is", epoch)
print("Number of batches", int(X_train.shape[0]/BATCH_SIZE))
for index in range(int(X_train.shape[0]/BATCH_SIZE)):#每轮有多少个step，数据/batch_size
noise = np.random.uniform(-1, 1, size=(BATCH_SIZE, 100))#生成100维度的噪声
image_batch = X_train[index*BATCH_SIZE:(index+1)*BATCH_SIZE]
generated_images = g.predict(noise, verbose=0)#生成器生成的图像
if index % 20 == 0:
image = combine_images(generated_images)#这个是把20张图像拼接起来，组成一个大图像
image = image*127.5+127.5#从-1~1还原成0~255
Image.fromarray(image.astype(np.uint8)).save(
str(epoch)+"_"+str(index)+".png")#保存图像
X = np.concatenate((image_batch, generated_images))
y = [1] * BATCH_SIZE + [0] * BATCH_SIZE
d_loss = d.train_on_batch(X, y)#训练判断器
print("batch %d d_loss : %f" % (index, d_loss))
noise = np.random.uniform(-1, 1, (BATCH_SIZE, 100))
d.trainable = False#把判断器冻结
g_loss = d_on_g.train_on_batch(noise, [1] * BATCH_SIZE)#固定判断器参数，训练生成器
d.trainable = True
print("batch %d g_loss : %f" % (index, g_loss))
if index % 10 == 9:
#每更新十次，保存模型
g.save_weights('generator', True)
d.save_weights('discriminator', True)
#加载训练好的模型进行预测
def generate(BATCH_SIZE, nice=False):
g = generator_model()
g.compile(loss='binary_crossentropy', optimizer="SGD")
g.load_weights('generator')
#生成比较好的模型
if nice:
d = discriminator_model()
d.compile(loss='binary_crossentropy', optimizer="SGD")
d.load_weights('discriminator')
noise = np.random.uniform(-1, 1, (BATCH_SIZE*20, 100))
generated_images = g.predict(noise, verbose=1)
d_pret = d.predict(generated_images, verbose=1)
index = np.arange(0, BATCH_SIZE*20)
index.resize((BATCH_SIZE*20, 1))
pre_with_index = list(np.append(d_pret, index, axis=1))
pre_with_index.sort(key=lambda x: x[0], reverse=True)
nice_images = np.zeros((BATCH_SIZE,) + generated_images.shape[1:3], dtype=np.float32)
nice_images = nice_images[:, :, :, None]
for i in range(BATCH_SIZE):
idx = int(pre_with_index[i][1])
nice_images[i, :, :, 0] = generated_images[idx, :, :, 0]
image = combine_images(nice_images)
#生成一般的模型
else:
noise = np.random.uniform(-1, 1, (BATCH_SIZE, 100))
generated_images = g.predict(noise, verbose=1)
image = combine_images(generated_images)
image = image*127.5+127.5
Image.fromarray(image.astype(np.uint8)).save(
"generated_image.png")
def get_args():
parser = argparse.ArgumentParser()
parser.add_argument("--mode", type=str,default='train')
parser.add_argument("--batch_size", type=int, default=128)
parser.add_argument("--nice", dest="nice", action="store_true")
parser.set_defaults(nice=False)
args = parser.parse_args()
return args
if __name__ == "__main__":
args = get_args()
if args.mode == "train":
train(BATCH_SIZE=args.batch_size)
elif args.mode == "generate":
generate(BATCH_SIZE=args.batch_size, nice=args.nice)
实验结果
迭代的次数还不够，生成的效果不算太好，若有兴趣，可以多增加迭代次数，会生成更好的图像。