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使用Python实现的CIFARNet算法进行图像分类

发布时间:2024-01-06 15:55:22

CIFARNet是一种基于深度学习的算法,用于在CIFAR-10数据集上进行图像分类。CIFAR-10数据集是一个包含10个分类的图像数据集,每个分类有6000张32x32的彩色图像。

下面是使用Python实现CIFARNet算法进行图像分类的示例:

首先,我们需要导入必要的库:

import torch
import torch.nn as nn
import torch.optim as optim
import torchvision
import torchvision.transforms as transforms

接下来,我们需要定义CIFARNet模型。这里我们使用一个简单的卷积神经网络作为模型:

class CIFARNet(nn.Module):

    def __init__(self):
        super(CIFARNet, self).__init__()
        self.conv1 = nn.Conv2d(3, 32, kernel_size=5)
        self.pool = nn.MaxPool2d(kernel_size=2, stride=2)
        self.conv2 = nn.Conv2d(32, 64, kernel_size=5)
        self.fc1 = nn.Linear(64 * 5 * 5, 512)
        self.fc2 = nn.Linear(512, 10)

    def forward(self, x):
        x = self.pool(F.relu(self.conv1(x)))
        x = self.pool(F.relu(self.conv2(x)))
        x = x.view(-1, 64 * 5 * 5)
        x = F.relu(self.fc1(x))
        x = self.fc2(x)
        return x

接下来,我们需要加载训练数据集和测试数据集,并对数据进行预处理:

transform = transforms.Compose(
    [transforms.ToTensor(),
     transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))])

trainset = torchvision.datasets.CIFAR10(root='./data', train=True,
                                        download=True, transform=transform)
trainloader = torch.utils.data.DataLoader(trainset, batch_size=4,
                                          shuffle=True, num_workers=2)

testset = torchvision.datasets.CIFAR10(root='./data', train=False,
                                       download=True, transform=transform)
testloader = torch.utils.data.DataLoader(testset, batch_size=4,
                                         shuffle=False, num_workers=2)

然后,我们可以创建CIFARNet模型的实例,选择合适的损失函数和优化器:

net = CIFARNet()
criterion = nn.CrossEntropyLoss()
optimizer = optim.SGD(net.parameters(), lr=0.001, momentum=0.9)

接下来,我们可以定义训练函数和测试函数:

def train(net, trainloader, criterion, optimizer, epochs):
    for epoch in range(epochs):
        running_loss = 0.0
        for i, data in enumerate(trainloader, 0):
            inputs, labels = data

            optimizer.zero_grad()

            outputs = net(inputs)
            loss = criterion(outputs, labels)
            loss.backward()
            optimizer.step()

            running_loss += loss.item()
            if i % 2000 == 1999:
                print('[%d, %5d] loss: %.3f' %
                      (epoch + 1, i + 1, running_loss / 2000))
                running_loss = 0.0

def test(net, testloader):
    correct = 0
    total = 0
    with torch.no_grad():
        for data in testloader:
            images, labels = data
            outputs = net(images)
            _, predicted = torch.max(outputs.data, 1)
            total += labels.size(0)
            correct += (predicted == labels).sum().item()

    print('Accuracy of the network on the 10000 test images: %d %%' % (
            100 * correct / total))

最后,我们可以调用训练函数和测试函数来训练和测试CIFARNet模型:

train(net, trainloader, criterion, optimizer, epochs=2)
test(net, testloader)

通过执行上面的代码,我们可以使用CIFARNet算法对CIFAR-10数据集中的图像进行分类,并获得模型的准确率。