基于DCGAN的MNIST手写数字生成
时间: 2023-07-05 15:26:18 浏览: 129
DCGAN是一种基于卷积神经网络的生成对抗网络,可以用来生成逼真的图像。MNIST是一个手写数字数据集,包含了许多28x28像素的灰度图像,可以用来测试生成模型的效果。
基于DCGAN的MNIST手写数字生成的步骤如下:
1. 首先,需要准备MNIST数据集,并将图片像素值归一化到[-1, 1]区间内。
2. 构建生成器网络和判别器网络,其中生成器网络负责生成逼真的手写数字图像,判别器网络则负责判断输入的图像是真实的MNIST图像还是生成器生成的假图像。
3. 使用Adam优化器训练生成器和判别器,让它们相互竞争,不断提高自己的能力,直到生成器可以产生逼真的手写数字图像。
4. 在训练过程中,可以定期生成一些图像来检查生成器的效果,直到生成的图像足够逼真。
5. 最后,可以使用生成器来生成新的手写数字图像,或者将生成器与其他模型结合来完成更复杂的任务。
相关问题
基于DCGAN的MNIST手写数字生成代码
以下是基于DCGAN的MNIST手写数字生成的Python代码示例:
```python
import torch
import torchvision
import torchvision.transforms as transforms
import torch.nn as nn
import torch.optim as optim
import numpy as np
# 定义生成器网络
class Generator(nn.Module):
def __init__(self):
super(Generator, self).__init__()
self.fc1 = nn.Linear(100, 128)
self.fc2 = nn.Linear(128, 256)
self.fc3 = nn.Linear(256, 512)
self.fc4 = nn.Linear(512, 784)
self.relu = nn.ReLU()
self.tanh = nn.Tanh()
def forward(self, x):
x = self.relu(self.fc1(x))
x = self.relu(self.fc2(x))
x = self.relu(self.fc3(x))
x = self.tanh(self.fc4(x))
return x
# 定义判别器网络
class Discriminator(nn.Module):
def __init__(self):
super(Discriminator, self).__init__()
self.fc1 = nn.Linear(784, 512)
self.fc2 = nn.Linear(512, 256)
self.fc3 = nn.Linear(256, 1)
self.relu = nn.ReLU()
self.sigmoid = nn.Sigmoid()
def forward(self, x):
x = self.relu(self.fc1(x))
x = self.relu(self.fc2(x))
x = self.sigmoid(self.fc3(x))
return x
# 准备数据集
transform = transforms.Compose(
[transforms.ToTensor(),
transforms.Normalize((0.5,), (0.5,))])
trainset = torchvision.datasets.MNIST(root='./data', train=True,
download=True, transform=transform)
trainloader = torch.utils.data.DataLoader(trainset, batch_size=128,
shuffle=True, num_workers=2)
# 初始化生成器和判别器
G = Generator()
D = Discriminator()
# 定义损失函数和优化器
criterion = nn.BCELoss()
optimizer_G = optim.Adam(G.parameters(), lr=0.0002, betas=(0.5, 0.999))
optimizer_D = optim.Adam(D.parameters(), lr=0.0002, betas=(0.5, 0.999))
# 训练模型
for epoch in range(50):
for i, data in enumerate(trainloader, 0):
# 更新判别器
D.zero_grad()
real_images = data[0].view(-1, 784)
real_labels = torch.ones(real_images.size()[0], 1)
fake_labels = torch.zeros(real_images.size()[0], 1)
# 训练鉴别器以识别真实图片
real_output = D(real_images)
real_loss = criterion(real_output, real_labels)
# 训练鉴别器以识别生成的图片
noise = torch.randn(real_images.size()[0], 100)
fake_images = G(noise)
fake_output = D(fake_images.detach())
fake_loss = criterion(fake_output, fake_labels)
# 更新判别器的权重
d_loss = real_loss + fake_loss
d_loss.backward()
optimizer_D.step()
# 更新生成器
G.zero_grad()
noise = torch.randn(real_images.size()[0], 100)
fake_images = G(noise)
fake_output = D(fake_images)
g_loss = criterion(fake_output, real_labels)
g_loss.backward()
optimizer_G.step()
# 定期生成一些图像来检查生成器的效果
if epoch % 5 == 0:
noise = torch.randn(25, 100)
generated_images = G(noise).detach().numpy()
generated_images = np.reshape(generated_images, (25, 28, 28))
generated_images = (generated_images + 1) / 2
torchvision.utils.save_image(torch.from_numpy(generated_images), 'generated_images_{}.png'.format(epoch))
print('Finished Training')
```
在训练过程中,生成器会不断生成手写数字图像,判别器会不断判断这些图像是真实的MNIST图像还是生成器生成的假图像。通过不断调整生成器和判别器的权重,生成器可以产生逼真的手写数字图像。最终,我们可以使用生成器来生成新的手写数字图像。
mnist手写数字生成pytorch
以下是一个基于GAN的mnist手写数字生成的PyTorch代码示例:
```python
import torch
import torch.nn as nn
from torchvision.datasets import MNIST
from torchvision.transforms import ToTensor
from torch.utils.data import DataLoader
# 定义生成器
class Generator(nn.Module):
def __init__(self, input_size, hidden_size, output_size):
super(Generator, self).__init__()
self.fc1 = nn.Linear(input_size, hidden_size)
self.fc2 = nn.Linear(hidden_size, hidden_size)
self.fc3 = nn.Linear(hidden_size, output_size)
self.relu = nn.ReLU()
def forward(self, x):
x = self.relu(self.fc1(x))
x = self.relu(self.fc2(x))
x = self.fc3(x)
return x
# 定义判别器
class Discriminator(nn.Module):
def __init__(self, input_size, hidden_size):
super(Discriminator, self).__init__()
self.fc1 = nn.Linear(input_size, hidden_size)
self.fc2 = nn.Linear(hidden_size, hidden_size)
self.fc3 = nn.Linear(hidden_size, 1)
self.sigmoid = nn.Sigmoid()
def forward(self, x):
x = self.sigmoid(self.fc1(x))
x = self.sigmoid(self.fc2(x))
x = self.sigmoid(self.fc3(x))
return x
# 定义超参数
input_size = 100
hidden_size = 256
output_size = 784
batch_size = 128
num_epochs = 200
# 加载MNIST数据集
train_dataset = MNIST(root='./data', train=True, transform=ToTensor(), download=True)
train_loader = DataLoader(train_dataset, batch_size=batch_size, shuffle=True)
# 初始化网络
G = Generator(input_size, hidden_size, output_size)
D = Discriminator(output_size, hidden_size)
# 定义损失函数和优化器
criterion = nn.BCELoss()
lr = 0.0002
G_optimizer = torch.optim.Adam(G.parameters(), lr=lr)
D_optimizer = torch.optim.Adam(D.parameters(), lr=lr)
# 定义真实和假的标签
real_label = torch.ones(batch_size, 1)
fake_label = torch.zeros(batch_size, 1)
# 训练网络
for epoch in range(num_epochs):
for i, (images, _) in enumerate(train_loader):
# 定义真实和假的图像
real_images = images.view(batch_size, -1)
z = torch.randn(batch_size, input_size)
fake_images = G(z)
# 训练判别器
D_real_loss = criterion(D(real_images), real_label)
D_fake_loss = criterion(D(fake_images.detach()), fake_label)
D_loss = D_real_loss + D_fake_loss
D_optimizer.zero_grad()
D_loss.backward()
D_optimizer.step()
# 训练生成器
G_loss = criterion(D(fake_images), real_label)
G_optimizer.zero_grad()
G_loss.backward()
G_optimizer.step()
# 打印损失
if (i+1) % 100 == 0:
print('Epoch [{}/{}], Step [{}/{}], D Loss: {:.4f}, G Loss: {:.4f}'
.format(epoch+1, num_epochs, i+1, len(train_loader), D_loss.item(), G_loss.item()))
# 保存模型
torch.save(G.state_dict(), 'generator.pth')
```
在训练完成后,可以使用生成器来生成新的手写数字图像,例如:
```python
import matplotlib.pyplot as plt
import numpy as np
# 加载生成器
G = Generator(input_size, hidden_size, output_size)
G.load_state_dict(torch.load('generator.pth'))
# 生成图像
z = torch.randn(1, input_size)
fake_image = G(z).detach().numpy()
fake_image = np.reshape(fake_image, (28, 28))
# 显示图像
plt.imshow(fake_image, cmap='gray')
plt.show()
```
这样就可以生成一个随机的手写数字图像了。