这篇文章尝试着分析了一下标准的GAN网络代码书写，由于十分复杂，不易复现，所以后面进行了简单的GAN网络结构的尝试。
『cs231n』通过代码理解gan网络&tensorflow共享变量机制_上
上篇是一个尝试生成minist手写体数据的简单GAN网络，之前有介绍过，图片维度是28*28*1，生成器的上采样使用的是tf.image.resize_image()，不太正规，不过其他部分很标准，值得参考学习。
辨别器：
n,28,28,1 ：
卷积 + 激活 + 池化n,14,14,32 ：
卷积 + 激活 + 池化n,7,7,64 ：
reshapen,7*7*64 ：
全连接 + 激活n,1024 ：
全连接n,1
生成器：
n,100（噪声长度） ：全链接
n,3136 ：reshape +
批正则化 + 激活n,56,56,1 ：
卷积 + 批正则化 + 激活n,28,28,50 ：插值
n,56,56,50 ：
卷积 + 批正则化 + 激活n,28,28,25 ：插值
n,56,56,25 ：
卷积 + 激活n,28,28,1
这是一个尝试生成头像的GAN，输入图片尺寸是64*64*3，由于作者对于tensorflow中网络reuse不熟悉，所以在网络结构上做了很大的改动（妥协），但是生成器正常的使用了conv_transpose，值得参考。
import os
import random
import numpy as np
import tensorflow as tf
from PIL import Image
# import cv2
import scipy.misc as misc
# 读取全部.jpg结尾的文件名
CELEBA_DATE_DIR = 'img_align_celeba'
train_images = []
for image_filename in os.listdir(CELEBA_DATE_DIR):
if image_filename.endswith('.jpg'):
train_images.append(os.path.join(CELEBA_DATE_DIR,image_filename))
# 打乱文件名排序
random.shuffle(train_images)
# 设置训练图片数据，包含批大小以及尺寸
batch_size = 64
num_batch = len(train_images) // batch_size
IMAGE_SIZE = 64
IMAGE_CHANNEL = 3
# 生成一batch的图片
def get_next_batch(pointer):
image_batch = []
images = train_images[pointer * batch_size:(pointer + 1) * batch_size]
for img in images:
arr = Image.open(img)
arr = arr.resize((IMAGE_SIZE,IMAGE_SIZE))
arr = np.array(arr)
arr = arr.astype('float32') / 127.5 - 1
# image = cv2.imread(img)
# image = cv2.resize(image, (IMAGE_SIZE, IMAGE_SIZE))
# image = image.astype('float32') / 127.5 - 1
image_batch.append(arr)
return image_batch
# 噪声接受
z_dim = 100
noise = tf.placeholder(tf.float32,[None,z_dim],name='noise')
# 训练数据接收
X = tf.placeholder(tf.float32,[batch_size,IMAGE_SIZE,IMAGE_SIZE,IMAGE_CHANNEL],name='X')
# 是否在训练阶段的flag接收
train_phase = tf.placeholder(tf.bool)
# batch_norm层
# http://*.com/a/34634291/2267819
def batch_norm(x,beta,gamma,phase_train,scope='bn',decay=0.9,eps=1e-5):
with tf.variable_scope(scope):
# beta = tf.get_variable(name='beta', shape=[n_out], initializer=tf.constant_initializer(0.0), trainable=True)
# gamma = tf.get_variable(name='gamma', shape=[n_out],
# initializer=tf.random_normal_initializer(1.0, stddev), trainable=True)
batch_mean,batch_var = tf.nn.moments(x,[0,1,2],name='moments')
ema = tf.train.ExponentialMovingAverage(decay=decay)
def mean_var_with_update():
ema_apply_op = ema.apply([batch_mean,batch_var])
with tf.control_dependencies([ema_apply_op]):
return tf.identity(batch_mean),tf.identity(batch_var)
mean,var = tf.cond(phase_train,
mean_var_with_update,
lambda: (ema.average(batch_mean),ema.average(batch_var)))
normed = tf.nn.batch_normalization(x,mean,var,beta,gamma,eps)
# https://www.jianshu.com/p/0312e04e4e83
# tf.nn.moments
# tf.nn.batch_normalization
return normed
# 生成器参数初始化
# 权重偏执&batch_normal层参数
generator_variables_dict = {
"W_1": tf.Variable(tf.truncated_normal([z_dim,2 * IMAGE_SIZE * IMAGE_SIZE],stddev=0.02),name='Generator/W_1'),
"b_1": tf.Variable(tf.constant(0.0,shape=[2 * IMAGE_SIZE * IMAGE_SIZE]),name='Generator/b_1'),
'beta_1': tf.Variable(tf.constant(0.0,shape=[512]),name='Generator/beta_1'),
'gamma_1': tf.Variable(tf.random_normal(shape=[512],mean=1.0,stddev=0.02),name='Generator/gamma_1'),
"W_2": tf.Variable(tf.truncated_normal([5,5,256,512],stddev=0.02),name='Generator/W_2'),
"b_2": tf.Variable(tf.constant(0.0,shape=[256]),name='Generator/b_2'),
'beta_2': tf.Variable(tf.constant(0.0,shape=[256]),name='Generator/beta_2'),
'gamma_2': tf.Variable(tf.random_normal(shape=[256],mean=1.0,stddev=0.02),name='Generator/gamma_2'),
"W_3": tf.Variable(tf.truncated_normal([5,5,128,256],stddev=0.02),name='Generator/W_3'),
"b_3": tf.Variable(tf.constant(0.0,shape=[128]),name='Generator/b_3'),
'beta_3': tf.Variable(tf.constant(0.0,shape=[128]),name='Generator/beta_3'),
'gamma_3': tf.Variable(tf.random_normal(shape=[128],mean=1.0,stddev=0.02),name='Generator/gamma_3'),
"W_4": tf.Variable(tf.truncated_normal([5,5,64,128],stddev=0.02),name='Generator/W_4'),
"b_4": tf.Variable(tf.constant(0.0,shape=[64]),name='Generator/b_4'),
'beta_4': tf.Variable(tf.constant(0.0,shape=[64]),name='Generator/beta_4'),
'gamma_4': tf.Variable(tf.random_normal(shape=[64],mean=1.0,stddev=0.02),name='Generator/gamma_4'),
"W_5": tf.Variable(tf.truncated_normal([5,5,IMAGE_CHANNEL,64],stddev=0.02),name='Generator/W_5'),
"b_5": tf.Variable(tf.constant(0.0,shape=[IMAGE_CHANNEL]),name='Generator/b_5')
}
# Generator
# 矩阵拼接的函数tf.stack()
# 矩阵分解的函数tf.unstack()
def generator(noise):
with tf.variable_scope("Generator"):
out_1 = tf.matmul(noise,generator_variables_dict["W_1"]) + generator_variables_dict['b_1']
out_1 = tf.reshape(out_1,[-1,IMAGE_SIZE // 16,IMAGE_SIZE // 16,512])
out_1 = batch_norm(out_1,generator_variables_dict["beta_1"],generator_variables_dict["gamma_1"],train_phase,
scope='bn_1')
out_1 = tf.nn.relu(out_1,name='relu_1')
out_2 = tf.nn.conv2d_transpose(out_1,generator_variables_dict['W_2'],
output_shape=tf.stack([tf.shape(out_1)[0],IMAGE_SIZE // 8,IMAGE_SIZE // 8,256]),
strides=[1,2,2,1],padding='SAME')
out_2 = tf.nn.bias_add(out_2,generator_variables_dict['b_2'])
out_2 = batch_norm(out_2,generator_variables_dict["beta_2"],generator_variables_dict["gamma_2"],train_phase,
scope='bn_2')
out_2 = tf.nn.relu(out_2,name='relu_2')
out_3 = tf.nn.conv2d_transpose(out_2,generator_variables_dict['W_3'],
output_shape=tf.stack([tf.shape(out_2)[0],IMAGE_SIZE // 4,IMAGE_SIZE // 4,128]),
strides=[1,2,2,1],padding='SAME')
out_3 = tf.nn.bias_add(out_3,generator_variables_dict['b_3'])
out_3 = batch_norm(out_3,generator_variables_dict["beta_3"],generator_variables_dict["gamma_3"],train_phase,
scope='bn_3')
out_3 = tf.nn.relu(out_3,name='relu_3')
out_4 = tf.nn.conv2d_transpose(out_3,generator_variables_dict['W_4'],
output_shape=tf.stack([tf.shape(out_3)[0],IMAGE_SIZE // 2,IMAGE_SIZE // 2,64]),
strides=[1,2,2,1],padding='SAME')
out_4 = tf.nn.bias_add(out_4,generator_variables_dict['b_4'])
out_4 = batch_norm(out_4,generator_variables_dict["beta_4"],generator_variables_dict["gamma_4"],train_phase,
scope='bn_4')
out_4 = tf.nn.relu(out_4,name='relu_4')
out_5 = tf.nn.conv2d_transpose(out_4,generator_variables_dict['W_5'],
output_shape=tf.stack([tf.shape(out_4)[0],IMAGE_SIZE,IMAGE_SIZE,IMAGE_CHANNEL]),
strides=[1,2,2,1],padding='SAME')
out_5 = tf.nn.bias_add(out_5,generator_variables_dict['b_5'])
out_5 = tf.nn.tanh(out_5,name='tanh_5')
return out_5
# 鉴别器参数初始化
# 权重偏执&batch_normal层参数
discriminator_variables_dict = {
"W_1": tf.Variable(tf.truncated_normal([4,4,IMAGE_CHANNEL,32],stddev=0.002),name='Discriminator/W_1'),
"b_1": tf.Variable(tf.constant(0.0,shape=[32]),name='Discriminator/b_1'),
'beta_1': tf.Variable(tf.constant(0.0,shape=[32]),name='Discriminator/beta_1'),
'gamma_1': tf.Variable(tf.random_normal(shape=[32],mean=1.0,stddev=0.02),name='Discriminator/gamma_1'),
"W_2": tf.Variable(tf.truncated_normal([4,4,32,64],stddev=0.002),name='Discriminator/W_2'),
"b_2": tf.Variable(tf.constant(0.0,shape=[64]),name='Discriminator/b_2'),
'beta_2': tf.Variable(tf.constant(0.0,shape=[64]),name='Discriminator/beta_2'),
'gamma_2': tf.Variable(tf.random_normal(shape=[64],mean=1.0,stddev=0.02),name='Discriminator/gamma_2'),
"W_3": tf.Variable(tf.truncated_normal([4,4,64,128],stddev=0.002),name='Discriminator/W_3'),
"b_3": tf.Variable(tf.constant(0.0,shape=[128]),name='Discriminator/b_3'),
'beta_3': tf.Variable(tf.constant(0.0,shape=[128]),name='Discriminator/beta_3'),
'gamma_3': tf.Variable(tf.random_normal(shape=[128],mean=1.0,stddev=0.02),name='Discriminator/gamma_3'),
"W_4": tf.Variable(tf.truncated_normal([4,4,64,128],stddev=0.002),name='Discriminator/W_4'),
"b_4": tf.Variable(tf.constant(0.0,shape=[64]),name='Discriminator/b_4'),
'beta_4': tf.Variable(tf.constant(0.0,shape=[64]),name='Discriminator/beta_4'),
'gamma_4': tf.Variable(tf.random_normal(shape=[64],mean=1.0,stddev=0.02),name='Discriminator/gamma_4'),
"W_5": tf.Variable(tf.truncated_normal([4,4,32,64],stddev=0.002),name='Discriminator/W_5'),
"b_5": tf.Variable(tf.constant(0.0,shape=[32]),name='Discriminator/b_5'),
'beta_5': tf.Variable(tf.constant(0.0,shape=[32]),name='Discriminator/beta_5'),
'gamma_5': tf.Variable(tf.random_normal(shape=[32],mean=1.0,stddev=0.02),name='Discriminator/gamma_5'),
"W_6": tf.Variable(tf.truncated_normal([4,4,3,32],stddev=0.002),name='Discriminator/W_6'),
"b_6": tf.Variable(tf.constant(0.0,shape=[3]),name='Discriminator/b_6')
}
# Discriminator
def discriminator(input_images):
with tf.variable_scope("Discriminator"):
# Encoder
out_1 = tf.nn.conv2d(input_images,discriminator_variables_dict['W_1'],strides=[1,2,2,1],padding='SAME')
out_1 = tf.nn.bias_add(out_1,discriminator_variables_dict['b_1'])
out_1 = batch_norm(out_1,discriminator_variables_dict['beta_1'],discriminator_variables_dict['gamma_1'],
train_phase,scope='bn_1')
out_1 = tf.maximum(0.2 * out_1,out_1,'leaky_relu_1')
out_2 = tf.nn.conv2d(out_1,discriminator_variables_dict['W_2'],strides=[1,2,2,1],padding='SAME')
out_2 = tf.nn.bias_add(out_2,discriminator_variables_dict['b_2'])
out_2 = batch_norm(out_2,discriminator_variables_dict['beta_2'],discriminator_variables_dict['gamma_2'],
train_phase,scope='bn_2')
out_2 = tf.maximum(0.2 * out_2,out_2,'leaky_relu_2')
out_3 = tf.nn.conv2d(out_2,discriminator_variables_dict['W_3'],strides=[1,2,2,1],padding='SAME')
out_3 = tf.nn.bias_add(out_3,discriminator_variables_dict['b_3'])
out_3 = batch_norm(out_3,discriminator_variables_dict['beta_3'],discriminator_variables_dict['gamma_3'],
train_phase,scope='bn_3')
out_3 = tf.maximum(0.2 * out_3,out_3,'leaky_relu_3')
encode = tf.reshape(out_3,[-1,2 * IMAGE_SIZE * IMAGE_SIZE])
# Decoder
out_3 = tf.reshape(encode,[-1,IMAGE_SIZE // 8,IMAGE_SIZE // 8,128])
out_4 = tf.nn.conv2d_transpose(out_3,discriminator_variables_dict['W_4'],
output_shape=tf.stack([tf.shape(out_3)[0],IMAGE_SIZE // 4,IMAGE_SIZE // 4,64]),
strides=[1,2,2,1],padding='SAME')
out_4 = tf.nn.bias_add(out_4,discriminator_variables_dict['b_4'])
out_4 = batch_norm(out_4,discriminator_variables_dict['beta_4'],discriminator_variables_dict['gamma_4'],
train_phase,scope='bn_4')
out_4 = tf.maximum(0.2 * out_4,out_4,'leaky_relu_4')
out_5 = tf.nn.conv2d_transpose(out_4,discriminator_variables_dict['W_5'],
output_shape=tf.stack([tf.shape(out_4)[0],IMAGE_SIZE // 2,IMAGE_SIZE // 2,32]),
strides=[1,2,2,1],padding='SAME')
out_5 = tf.nn.bias_add(out_5,discriminator_variables_dict['b_5'])
out_5 = batch_norm(out_5,discriminator_variables_dict['beta_5'],discriminator_variables_dict['gamma_5'],
train_phase,scope='bn_5')
out_5 = tf.maximum(0.2 * out_5,out_5,'leaky_relu_5')
out_6 = tf.nn.conv2d_transpose(out_5,discriminator_variables_dict['W_6'],
output_shape=tf.stack([tf.shape(out_5)[0],IMAGE_SIZE,IMAGE_SIZE,3]),
strides=[1,2,2,1],padding='SAME')
out_6 = tf.nn.bias_add(out_6,discriminator_variables_dict['b_6'])
decoded = tf.nn.tanh(out_6,name="tanh_6")
return encode,decoded
结构如下，
辨别器：
64，64，3
32，32，32
16，16，64
8，8，128
64×64×2
8，8，128
16，16，64
32，32，32
64，64，3
生成器：
100
64×64×2
4，4，512
8，8，256
16，16，128
32，32，64
64，64，3
损失函数以及训练策略很有意思，
这里面涉及的很多tensorflow操作都很到位，应该好好学习一下，
# mean squared errors
_,real_decoded = discriminator(X)
real_loss = tf.sqrt(2 * tf.nn.l2_loss(real_decoded - X)) / batch_size
fake_image = generator(noise)
_,fake_decoded = discriminator(fake_image)
fake_loss = tf.sqrt(2 * tf.nn.l2_loss(fake_decoded - fake_image)) / batch_size
# loss
# D_loss = real_loss + tf.maximum(1 - fake_loss, 0)
margin = 20
D_loss = margin - fake_loss + real_loss
G_loss = fake_loss # no pt
def optimizer(loss,d_or_g):
optim = tf.train.AdamOptimizer(learning_rate=0.001,beta1=0.5)
# print([v.name for v in tf.trainable_variables() if v.name.startswith(d_or_g)])
var_list = [v for v in tf.trainable_variables() if v.name.startswith(d_or_g)]
gradient = optim.compute_gradients(loss,var_list=var_list)
return optim.apply_gradients(gradient)
train_op_G = optimizer(G_loss,'Generator')
train_op_D = optimizer(D_loss,'Discriminator')
训练部分的重载模型参数，属于之前一直没有注意到的细节，
with tf.Session() as sess:
sess.run(tf.global_variables_initializer(),feed_dict={train_phase: True})
saver = tf.train.Saver()
# 恢复前一次训练
ckpt = tf.train.get_checkpoint_state('.')
if ckpt != None:
print(ckpt.model_checkpoint_path)
saver.restore(sess,ckpt.model_checkpoint_path)
else:
print("没找到模型")
step = 0
for i in range(40):
for j in range(num_batch):
batch_noise = np.random.uniform(-1.0,1.0,size=[batch_size,z_dim]).astype(np.float32)
d_loss,_ = sess.run([D_loss,train_op_D],
feed_dict={noise: batch_noise,X: get_next_batch(j),train_phase: True})
g_loss,_ = sess.run([G_loss,train_op_G],
feed_dict={noise: batch_noise,X: get_next_batch(j),train_phase: True})
g_loss,_ = sess.run([G_loss,train_op_G],
feed_dict={noise: batch_noise,X: get_next_batch(j),train_phase: True})
print(step,d_loss,g_loss)
# 保存模型并生成图像
if step % 100 == 0:
saver.save(sess,"celeba.model",global_step=step)
test_noise = np.random.uniform(-1.0,1.0,size=(5,z_dim)).astype(np.float32)
images = sess.run(fake_image,feed_dict={noise: test_noise,train_phase: False})
for k in range(5):
image = images[k,:,:,:]
image += 1
image *= 127.5
image = np.clip(image,0,255).astype(np.uint8)
image = np.reshape(image,(IMAGE_SIZE,IMAGE_SIZE,-1))
misc.imsave('fake_image' + str(step) + str(k) + '.jpg',image)
step += 1