- 🍨 本文为🔗365天深度学习训练营 中的学习记录博客
- 🍖 原作者：K同学啊
准备工作
import torch
import numpy as np
import torch.nn as nn
import torch.optim as optim
from torchvision import datasets, transforms
from torch.autograd import Variable
from torchvision.utils import save_image
from torchvision.utils import make_grid
from torch.utils.tensorboard import SummaryWriter
from torchsummary import summary
import matplotlib.pyplot as plt
import datetime
torch.manual_seed(1)
<torch._C.Generator at 0x23c3bf41230>
device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
batch_size = 128
1. 导入数据
train_transform = transforms.Compose([
transforms.Resize(128),
transforms.ToTensor(),
transforms.Normalize([0.5,0.5,0.5], [0.5,0.5,0.5])])
train_dataset = datasets.ImageFolder(root=r'C:\Users\11054\Desktop\kLearning\G3\rps', transform=train_transform)
train_loader = torch.utils.data.DataLoader(dataset=train_dataset,
batch_size=batch_size,
shuffle=True,
num_workers=6)
2. 数据可视化
def show_images(images):
fig, ax = plt.subplots(figsize=(20, 20))
ax.set_xticks([]); ax.set_yticks([])
ax.imshow(make_grid(images.detach(), nrow=22).permute(1, 2, 0))
def show_batch(dl):
for images, _ in dl:
show_images(images)
break
show_batch(train_loader)
Clipping input data to the valid range for imshow with RGB data ([0..1] for floats or [0..255] for integers). Got range [-0.92941177..1.0].
image_shape = (3, 128, 128)
image_dim = int(np.prod(image_shape))
latent_dim = 100
n_classes = 3
embedding_dim = 100
构建模型
# 自定义权重初始化函数，用于初始化生成器和判别器的权重
def weights_init(m):
# 获取当前层的类名
classname = m.__class__.__name__
# 如果当前层是卷积层（类名中包含 'Conv' ）
if classname.find('Conv') != -1:
# 使用正态分布随机初始化权重，均值为0，标准差为0.02
torch.nn.init.normal_(m.weight, 0.0, 0.02)
# 如果当前层是批归一化层（类名中包含 'BatchNorm' ）
elif classname.find('BatchNorm') != -1:
# 使用正态分布随机初始化权重，均值为1，标准差为0.02
torch.nn.init.normal_(m.weight, 1.0, 0.02)
# 将偏置项初始化为全零
torch.nn.init.zeros_(m.bias)
1. 构建生成器
class Generator(nn.Module):
def __init__(self):
super(Generator, self).__init__()
# 定义条件标签的生成器部分，用于将标签映射到嵌入空间中
# n_classes：条件标签的总数
# embedding_dim：嵌入空间的维度
self.label_conditioned_generator = nn.Sequential(
nn.Embedding(n_classes, embedding_dim), # 使用Embedding层将条件标签映射为稠密向量
nn.Linear(embedding_dim, 16) # 使用线性层将稠密向量转换为更高维度
)
# 定义潜在向量的生成器部分，用于将噪声向量映射到图像空间中
# latent_dim：潜在向量的维度
self.latent = nn.Sequential(
nn.Linear(latent_dim, 4*4*512), # 使用线性层将潜在向量转换为更高维度
nn.LeakyReLU(0.2, inplace=True) # 使用LeakyReLU激活函数进行非线性映射
)
# 定义生成器的主要结构，将条件标签和潜在向量合并成生成的图像
self.model = nn.Sequential(
# 反卷积层1：将合并后的向量映射为64x8x8的特征图
nn.ConvTranspose2d(513, 64*8, 4, 2, 1, bias=False),
nn.BatchNorm2d(64*8, momentum=0.1, eps=0.8), # 批标准化
nn.ReLU(True), # ReLU激活函数
# 反卷积层2：将64x8x8的特征图映射为64x4x4的特征图
nn.ConvTranspose2d(64*8, 64*4, 4, 2, 1, bias=False),
nn.BatchNorm2d(64*4, momentum=0.1, eps=0.8),
nn.ReLU(True),
# 反卷积层3：将64x4x4的特征图映射为64x2x2的特征图
nn.ConvTranspose2d(64*4, 64*2, 4, 2, 1, bias=False),
nn.BatchNorm2d(64*2, momentum=0.1, eps=0.8),
nn.ReLU(True),
# 反卷积层4：将64x2x2的特征图映射为64x1x1的特征图
nn.ConvTranspose2d(64*2, 64*1, 4, 2, 1, bias=False),
nn.BatchNorm2d(64*1, momentum=0.1, eps=0.8),
nn.ReLU(True),
# 反卷积层5：将64x1x1的特征图映射为3x64x64的RGB图像
nn.ConvTranspose2d(64*1, 3, 4, 2, 1, bias=False),
nn.Tanh() # 使用Tanh激活函数将生成的图像像素值映射到[-1, 1]范围内
)
def forward(self, inputs):
noise_vector, label = inputs
# 通过条件标签生成器将标签映射为嵌入向量
label_output = self.label_conditioned_generator(label)
# 将嵌入向量的形状变为（batch_size, 1, 4, 4），以便与潜在向量进行合并
label_output = label_output.view(-1, 1, 4, 4)
# 通过潜在向量生成器将噪声向量映射为潜在向量
latent_output = self.latent(noise_vector)
# 将潜在向量的形状变为（batch_size, 512, 4, 4），以便与条件标签进行合并
latent_output = latent_output.view(-1, 512, 4, 4)
# 将条件标签和潜在向量在通道维度上进行合并，得到合并后的特征图
concat = torch.cat((latent_output, label_output), dim=1)
# 通过生成器的主要结构将合并后的特征图生成为RGB图像
image = self.model(concat)
return image
generator = Generator().to(device)
generator.apply(weights_init)
print(generator)
Generator(
(label_conditioned_generator): Sequential(
(0): Embedding(3, 100)
(1): Linear(in_features=100, out_features=16, bias=True)
)
(latent): Sequential(
(0): Linear(in_features=100, out_features=8192, bias=True)
(1): LeakyReLU(negative_slope=0.2, inplace=True)
)
(model): Sequential(
(0): ConvTranspose2d(513, 512, kernel_size=(4, 4), stride=(2, 2), padding=(1, 1), bias=False)
(1): BatchNorm2d(512, eps=0.8, momentum=0.1, affine=True, track_running_stats=True)
(2): ReLU(inplace=True)
(3): ConvTranspose2d(512, 256, kernel_size=(4, 4), stride=(2, 2), padding=(1, 1), bias=False)
(4): BatchNorm2d(256, eps=0.8, momentum=0.1, affine=True, track_running_stats=True)
(5): ReLU(inplace=True)
(6): ConvTranspose2d(256, 128, kernel_size=(4, 4), stride=(2, 2), padding=(1, 1), bias=False)
(7): BatchNorm2d(128, eps=0.8, momentum=0.1, affine=True, track_running_stats=True)
(8): ReLU(inplace=True)
(9): ConvTranspose2d(128, 64, kernel_size=(4, 4), stride=(2, 2), padding=(1, 1), bias=False)
(10): BatchNorm2d(64, eps=0.8, momentum=0.1, affine=True, track_running_stats=True)
(11): ReLU(inplace=True)
(12): ConvTranspose2d(64, 3, kernel_size=(4, 4), stride=(2, 2), padding=(1, 1), bias=False)
(13): Tanh()
)
)
from torchinfo import summary
summary(generator)
=================================================================
Layer (type:depth-idx) Param #
=================================================================
Generator --
├─Sequential: 1-1 --
│ └─Embedding: 2-1 300
│ └─Linear: 2-2 1,616
├─Sequential: 1-2 --
│ └─Linear: 2-3 827,392
│ └─LeakyReLU: 2-4 --
├─Sequential: 1-3 --
│ └─ConvTranspose2d: 2-5 4,202,496
│ └─BatchNorm2d: 2-6 1,024
│ └─ReLU: 2-7 --
│ └─ConvTranspose2d: 2-8 2,097,152
│ └─BatchNorm2d: 2-9 512
│ └─ReLU: 2-10 --
│ └─ConvTranspose2d: 2-11 524,288
│ └─BatchNorm2d: 2-12 256
│ └─ReLU: 2-13 --
│ └─ConvTranspose2d: 2-14 131,072
│ └─BatchNorm2d: 2-15 128
│ └─ReLU: 2-16 --
│ └─ConvTranspose2d: 2-17 3,072
│ └─Tanh: 2-18 --
=================================================================
Total params: 7,789,308
Trainable params: 7,789,308
Non-trainable params: 0
=================================================================
a = torch.ones(100)
b = torch.ones(1)
b = b.long()
a = a.to(device)
b = b.to(device)
# generator((a,b))
2. 构建鉴别器
import torch
import torch.nn as nn
class Discriminator(nn.Module):
def __init__(self):
super(Discriminator, self).__init__()
# 定义一个条件标签的嵌入层，用于将类别标签转换为特征向量
self.label_condition_disc = nn.Sequential(
nn.Embedding(n_classes, embedding_dim), # 嵌入层将类别标签编码为固定长度的向量
nn.Linear(embedding_dim, 3*128*128) # 线性层将嵌入的向量转换为与图像尺寸相匹配的特征张量
)
# 定义主要的鉴别器模型
self.model = nn.Sequential(
nn.Conv2d(6, 64, 4, 2, 1, bias=False), # 输入通道为6（包含图像和标签的通道数），输出通道为64，4x4的卷积核，步长为2，padding为1
nn.LeakyReLU(0.2, inplace=True), # LeakyReLU激活函数，带有负斜率，增加模型对输入中的负值的感知能力
nn.Conv2d(64, 64*2, 4, 3, 2, bias=False), # 输入通道为64，输出通道为64*2，4x4的卷积核，步长为3，padding为2
nn.BatchNorm2d(64*2, momentum=0.1, eps=0.8), # 批量归一化层，有利于训练稳定性和收敛速度
nn.LeakyReLU(0.2, inplace=True),
nn.Conv2d(64*2, 64*4, 4, 3, 2, bias=False), # 输入通道为64*2，输出通道为64*4，4x4的卷积核，步长为3，padding为2
nn.BatchNorm2d(64*4, momentum=0.1, eps=0.8),
nn.LeakyReLU(0.2, inplace=True),
nn.Conv2d(64*4, 64*8, 4, 3, 2, bias=False), # 输入通道为64*4，输出通道为64*8，4x4的卷积核，步长为3，padding为2
nn.BatchNorm2d(64*8, momentum=0.1, eps=0.8),
nn.LeakyReLU(0.2, inplace=True),
nn.Flatten(), # 将特征图展平为一维向量，用于后续全连接层处理
nn.Dropout(0.4), # 随机失活层，用于减少过拟合风险
nn.Linear(4608, 1), # 全连接层，将特征向量映射到输出维度为1的向量
nn.Sigmoid() # Sigmoid激活函数，用于输出范围限制在0到1之间的概率值
)
def forward(self, inputs):
img, label = inputs
# 将类别标签转换为特征向量
label_output = self.label_condition_disc(label)
# 重塑特征向量为与图像尺寸相匹配的特征张量
label_output = label_output.view(-1, 3, 128, 128)
# 将图像特征和标签特征拼接在一起作为鉴别器的输入
concat = torch.cat((img, label_output), dim=1)
# 将拼接后的输入通过鉴别器模型进行前向传播，得到输出结果
output = self.model(concat)
return output
discriminator = Discriminator().to(device)
discriminator.apply(weights_init)
print(discriminator)
Discriminator(
(label_condition_disc): Sequential(
(0): Embedding(3, 100)
(1): Linear(in_features=100, out_features=49152, bias=True)
)
(model): Sequential(
(0): Conv2d(6, 64, kernel_size=(4, 4), stride=(2, 2), padding=(1, 1), bias=False)
(1): LeakyReLU(negative_slope=0.2, inplace=True)
(2): Conv2d(64, 128, kernel_size=(4, 4), stride=(3, 3), padding=(2, 2), bias=False)
(3): BatchNorm2d(128, eps=0.8, momentum=0.1, affine=True, track_running_stats=True)
(4): LeakyReLU(negative_slope=0.2, inplace=True)
(5): Conv2d(128, 256, kernel_size=(4, 4), stride=(3, 3), padding=(2, 2), bias=False)
(6): BatchNorm2d(256, eps=0.8, momentum=0.1, affine=True, track_running_stats=True)
(7): LeakyReLU(negative_slope=0.2, inplace=True)
(8): Conv2d(256, 512, kernel_size=(4, 4), stride=(3, 3), padding=(2, 2), bias=False)
(9): BatchNorm2d(512, eps=0.8, momentum=0.1, affine=True, track_running_stats=True)
(10): LeakyReLU(negative_slope=0.2, inplace=True)
(11): Flatten(start_dim=1, end_dim=-1)
(12): Dropout(p=0.4, inplace=False)
(13): Linear(in_features=4608, out_features=1, bias=True)
(14): Sigmoid()
)
)
summary(discriminator)
=================================================================
Layer (type:depth-idx) Param #
=================================================================
Discriminator --
├─Sequential: 1-1 --
│ └─Embedding: 2-1 300
│ └─Linear: 2-2 4,964,352
├─Sequential: 1-2 --
│ └─Conv2d: 2-3 6,144
│ └─LeakyReLU: 2-4 --
│ └─Conv2d: 2-5 131,072
│ └─BatchNorm2d: 2-6 256
│ └─LeakyReLU: 2-7 --
│ └─Conv2d: 2-8 524,288
│ └─BatchNorm2d: 2-9 512
│ └─LeakyReLU: 2-10 --
│ └─Conv2d: 2-11 2,097,152
│ └─BatchNorm2d: 2-12 1,024
│ └─LeakyReLU: 2-13 --
│ └─Flatten: 2-14 --
│ └─Dropout: 2-15 --
│ └─Linear: 2-16 4,609
│ └─Sigmoid: 2-17 --
=================================================================
Total params: 7,729,709
Trainable params: 7,729,709
Non-trainable params: 0
=================================================================
a = torch.ones(2,3,128,128)
b = torch.ones(2,1)
b = b.long()
a = a.to(device)
b = b.to(device)
c = discriminator((a,b))
c.size()
torch.Size([2, 1])
训练模型
1. 定义损失函数
adversarial_loss = nn.BCELoss()
def generator_loss(fake_output, label):
gen_loss = adversarial_loss(fake_output, label)
return gen_loss
def discriminator_loss(output, label):
disc_loss = adversarial_loss(output, label)
return disc_loss
2. 定义优化器
learning_rate = 0.0002
G_optimizer = optim.Adam(generator.parameters(), lr = learning_rate, betas=(0.5, 0.999))
D_optimizer = optim.Adam(discriminator.parameters(), lr = learning_rate, betas=(0.5, 0.999))
3. 训练模型
# 设置训练的总轮数
num_epochs = 20
# 初始化用于存储每轮训练中判别器和生成器损失的列表
D_loss_plot, G_loss_plot = [], []
# 循环进行训练
for epoch in range(1, num_epochs + 1):
# 初始化每轮训练中判别器和生成器损失的临时列表
D_loss_list, G_loss_list = [], []
# 遍历训练数据加载器中的数据
for index, (real_images, labels) in enumerate(train_loader):
# 清空判别器的梯度缓存
D_optimizer.zero_grad()
# 将真实图像数据和标签转移到GPU（如果可用）
real_images = real_images.to(device)
labels = labels.to(device)
# 将标签的形状从一维向量转换为二维张量（用于后续计算）
labels = labels.unsqueeze(1).long()
# 创建真实目标和虚假目标的张量（用于判别器损失函数）
real_target = Variable(torch.ones(real_images.size(0), 1).to(device))
fake_target = Variable(torch.zeros(real_images.size(0), 1).to(device))
# 计算判别器对真实图像的损失
D_real_loss = discriminator_loss(discriminator((real_images, labels)), real_target)
# 从噪声向量中生成假图像（生成器的输入）
noise_vector = torch.randn(real_images.size(0), latent_dim, device=device)
noise_vector = noise_vector.to(device)
generated_image = generator((noise_vector, labels))
# 计算判别器对假图像的损失（注意detach()函数用于分离生成器梯度计算图）
output = discriminator((generated_image.detach(), labels))
D_fake_loss = discriminator_loss(output, fake_target)
# 计算判别器总体损失（真实图像损失和假图像损失的平均值）
D_total_loss = (D_real_loss + D_fake_loss) / 2
D_loss_list.append(D_total_loss)
# 反向传播更新判别器的参数
D_total_loss.backward()
D_optimizer.step()
# 清空生成器的梯度缓存
G_optimizer.zero_grad()
# 计算生成器的损失
G_loss = generator_loss(discriminator((generated_image, labels)), real_target)
G_loss_list.append(G_loss)
# 反向传播更新生成器的参数
G_loss.backward()
G_optimizer.step()
# 打印当前轮次的判别器和生成器的平均损失
print('Epoch: [%d/%d]: D_loss: %.3f, G_loss: %.3f' % (
(epoch), num_epochs, torch.mean(torch.FloatTensor(D_loss_list)),
torch.mean(torch.FloatTensor(G_loss_list))))
# 将当前轮次的判别器和生成器的平均损失保存到列表中
D_loss_plot.append(torch.mean(torch.FloatTensor(D_loss_list)))
G_loss_plot.append(torch.mean(torch.FloatTensor(G_loss_list)))
if epoch%10 == 0:
# 将生成的假图像保存为图片文件
save_image(generated_image.data[:50], f'C:/Users/11054/Desktop/kLearning/G3/images/sample_{epoch}.png', nrow=5, normalize=True)
# 将当前轮次的生成器和判别器的权重保存到文件
torch.save(generator.state_dict(), f'C:/Users/11054/Desktop/kLearning/G3/generator_epoch_{epoch}.pth')
torch.save(discriminator.state_dict(), f'C:/Users/11054/Desktop/kLearning/G3/discriminator_epoch_{epoch}.pth')
Epoch: [1/20]: D_loss: 0.328, G_loss: 1.420
Epoch: [2/20]: D_loss: 0.169, G_loss: 2.818
Epoch: [3/20]: D_loss: 0.261, G_loss: 2.547
Epoch: [4/20]: D_loss: 0.293, G_loss: 2.359
Epoch: [5/20]: D_loss: 0.301, G_loss: 2.415
Epoch: [6/20]: D_loss: 0.348, G_loss: 2.198
Epoch: [7/20]: D_loss: 0.346, G_loss: 2.292
Epoch: [8/20]: D_loss: 0.425, G_loss: 2.117
Epoch: [9/20]: D_loss: 0.470, G_loss: 1.596
模型分析
1. 加载模型
generator.load_state_dict(torch.load(f'C:/Users/11054/Desktop/kLearning/G3/generator_epoch_10.pth'), strict=False)
generator.eval()
Generator(
(label_conditioned_generator): Sequential(
(0): Embedding(3, 100)
(1): Linear(in_features=100, out_features=16, bias=True)
)
(latent): Sequential(
(0): Linear(in_features=100, out_features=8192, bias=True)
(1): LeakyReLU(negative_slope=0.2, inplace=True)
)
(model): Sequential(
(0): ConvTranspose2d(513, 512, kernel_size=(4, 4), stride=(2, 2), padding=(1, 1), bias=False)
(1): BatchNorm2d(512, eps=0.8, momentum=0.1, affine=True, track_running_stats=True)
(2): ReLU(inplace=True)
(3): ConvTranspose2d(512, 256, kernel_size=(4, 4), stride=(2, 2), padding=(1, 1), bias=False)
(4): BatchNorm2d(256, eps=0.8, momentum=0.1, affine=True, track_running_stats=True)
(5): ReLU(inplace=True)
(6): ConvTranspose2d(256, 128, kernel_size=(4, 4), stride=(2, 2), padding=(1, 1), bias=False)
(7): BatchNorm2d(128, eps=0.8, momentum=0.1, affine=True, track_running_stats=True)
(8): ReLU(inplace=True)
(9): ConvTranspose2d(128, 64, kernel_size=(4, 4), stride=(2, 2), padding=(1, 1), bias=False)
(10): BatchNorm2d(64, eps=0.8, momentum=0.1, affine=True, track_running_stats=True)
(11): ReLU(inplace=True)
(12): ConvTranspose2d(64, 3, kernel_size=(4, 4), stride=(2, 2), padding=(1, 1), bias=False)
(13): Tanh()
)
)
# 导入所需的库
from numpy import asarray
from numpy.random import randn
from numpy.random import randint
from numpy import linspace
from matplotlib import pyplot
from matplotlib import gridspec
# 生成潜在空间的点，作为生成器的输入
def generate_latent_points(latent_dim, n_samples, n_classes=3):
# 从标准正态分布中生成潜在空间的点
x_input = randn(latent_dim * n_samples)
# 将生成的点整形成用于神经网络的输入的批量
z_input = x_input.reshape(n_samples, latent_dim)
return z_input
# 在两个潜在空间点之间进行均匀插值
def interpolate_points(p1, p2, n_steps=10):
# 在两个点之间进行插值，生成插值比率
ratios = linspace(0, 1, num=n_steps)
# 线性插值向量
vectors = list()
for ratio in ratios:
v = (1.0 - ratio) * p1 + ratio * p2
vectors.append(v)
return asarray(vectors)
# 生成两个潜在空间的点
pts = generate_latent_points(100, 2)
# 在两个潜在空间点之间进行插值
interpolated = interpolate_points(pts[0], pts[1])
# 将数据转换为torch张量并将其移至GPU（假设device已正确声明为GPU）
interpolated = torch.tensor(interpolated).to(device).type(torch.float32)
output = None
# 对于三个类别的循环，分别进行插值和生成图片
for label in range(3):
# 创建包含相同类别标签的张量
labels = torch.ones(10) * label
labels = labels.to(device)
labels = labels.unsqueeze(1).long()
print(labels.size())
# 使用生成器生成插值结果
predictions = generator((interpolated, labels))
predictions = predictions.permute(0,2,3,1)
pred = predictions.detach().cpu()
if output is None:
output = pred
else:
output = np.concatenate((output,pred))
torch.Size([10, 1])
torch.Size([10, 1])
torch.Size([10, 1])
output.shape
(30, 128, 128, 3)
nrow = 3
ncol = 10
fig = plt.figure(figsize=(15,4))
gs = gridspec.GridSpec(nrow, ncol)
k = 0
for i in range(nrow):
for j in range(ncol):
pred = (output[k, :, :, :] + 1 ) * 127.5
pred = np.array(pred)
ax= plt.subplot(gs[i,j])
ax.imshow(pred.astype(np.uint8))
ax.set_xticklabels([])
ax.set_yticklabels([])
ax.axis('off')
k += 1
plt.show()
个人总结
CGAN 通过引入条件信息（Conditional Information） 来控制生成数据的类别或属性，从而增强生成数据的可控性和多样性，核心组件分析：
-
条件机制实现：
- 通过Embedding层将离散标签映射为连续向量（label_conditioned_generator/label_condition_disc）
- 使用Linear层调整维度后与图像特征拼接（forward中的concat操作）
-
生成器(Generator)关键设计：
- 输入：噪声向量( latent_dim ) + 类别标签( n_classes )
- 结构：5层转置卷积（ConvTranspose2d）实现上采样
- 输出：3通道RGB图像（Tanh激活归一化到[-1,1]）
- 创新点：将标签嵌入向量reshape为4x4特征图与噪声特征拼接
-
判别器(Discriminator)关键设计：
- 输入：真实/生成图像 + 对应标签特征
- 结构：4层卷积（Conv2d）实现下采样
- 输出：Sigmoid激活的单一概率值
- 特点：标签特征先转换为3x128x128伪图像再拼接
训练技巧观察：
-
参数配置：
- LeakyReLU(0.2)防止梯度消失
- BatchNorm momentum=0.1, eps=0.8 的非常规设置
- Dropout(0.4)防止判别器过拟合
-
维度变换：
- 生成器最终输出3x64x64图像（需注意与判别器输入尺寸匹配）
- 判别器Flatten后全连接层输入4608维（需根据输入尺寸计算）
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