resnet-34与unet结合的代码

这里是一个简单的ResNet-34与U-Net结合的代码示例，用于图像分割任务：

import torch
import torch.nn as nn
import torch.nn.functional as F

class ResNetBlock(nn.Module):
    def __init__(self, in_channels, out_channels):
        super(ResNetBlock, self).__init__()
        self.conv1 = nn.Conv2d(in_channels, out_channels, kernel_size=3, padding=1, bias=False)
        self.bn1 = nn.BatchNorm2d(out_channels)
        self.conv2 = nn.Conv2d(out_channels, out_channels, kernel_size=3, padding=1, bias=False)
        self.bn2 = nn.BatchNorm2d(out_channels)
        self.relu = nn.ReLU(inplace=True)
        
    def forward(self, x):
        identity = x
        
        out = self.conv1(x)
        out = self.bn1(out)
        out = self.relu(out)
        
        out = self.conv2(out)
        out = self.bn2(out)
        
        out += identity
        out = self.relu(out)
        
        return out

class ResNetEncoder(nn.Module):
    def __init__(self, in_channels, out_channels):
        super(ResNetEncoder, self).__init__()
        
        self.conv1 = nn.Conv2d(in_channels, out_channels, kernel_size=7, stride=2, padding=3, bias=False)
        self.bn1 = nn.BatchNorm2d(out_channels)
        self.relu = nn.ReLU(inplace=True)
        self.maxpool = nn.MaxPool2d(kernel_size=3, stride=2, padding=1)
        
        self.layer1 = nn.Sequential(
            ResNetBlock(out_channels, out_channels),
            ResNetBlock(out_channels, out_channels),
            ResNetBlock(out_channels, out_channels),
        )
        self.layer2 = nn.Sequential(
            ResNetBlock(out_channels, out_channels*2),
            ResNetBlock(out_channels*2, out_channels*2),
            ResNetBlock(out_channels*2, out_channels*2),
        )
        self.layer3 = nn.Sequential(
            ResNetBlock(out_channels*2, out_channels*4),
            ResNetBlock(out_channels*4, out_channels*4),
            ResNetBlock(out_channels*4, out_channels*4),
            ResNetBlock(out_channels*4, out_channels*4),
            ResNetBlock(out_channels*4, out_channels*4),
            ResNetBlock(out_channels*4, out_channels*4),
        )
        self.layer4 = nn.Sequential(
            ResNetBlock(out_channels*4, out_channels*8),
            ResNetBlock(out_channels*8, out_channels*8),
            ResNetBlock(out_channels*8, out_channels*8),
        )
        
    def forward(self, x):
        x = self.conv1(x)
        x = self.bn1(x)
        x = self.relu(x)
        x = self.maxpool(x)
        
        x1 = self.layer1(x)
        x2 = self.layer2(x1)
        x3 = self.layer3(x2)
        x4 = self.layer4(x3)
        
        return x1, x2, x3, x4

class ResNetDecoder(nn.Module):
    def __init__(self, in_channels, out_channels):
        super(ResNetDecoder, self).__init__()
        
        self.layer1 = nn.Sequential(
            ResNetBlock(in_channels*8 + out_channels*8, out_channels*4),
            ResNetBlock(out_channels*4, out_channels*4),
            ResNetBlock(out_channels*4, out_channels*4),
        )
        self.layer2 = nn.Sequential(
            ResNetBlock(in_channels*4 + out_channels*4, out_channels*2),
            ResNetBlock(out_channels*2, out_channels*2),
            ResNetBlock(out_channels*2, out_channels*2),
        )
        self.layer3 = nn.Sequential(
            ResNetBlock(in_channels*2 + out_channels*2, out_channels),
            ResNetBlock(out_channels, out_channels),
            ResNetBlock(out_channels, out_channels),
        )
        self.layer4 = nn.Sequential(
            ResNetBlock(in_channels + out_channels, out_channels),
            ResNetBlock(out_channels, out_channels),
            ResNetBlock(out_channels, out_channels),
        )
        
        self.conv = nn.Conv2d(out_channels, 1, kernel_size=1)
        
    def forward(self, x1, x2, x3, x4):
        x = F.interpolate(x4, scale_factor=2)
        x = torch.cat([x, x3], dim=1)
        x = self.layer1(x)
        
        x = F.interpolate(x, scale_factor=2)
        x = torch.cat([x, x2], dim=1)
        x = self.layer2(x)
        
        x = F.interpolate(x, scale_factor=2)
        x = torch.cat([x, x1], dim=1)
        x = self.layer3(x)
        
        x = F.interpolate(x, scale_factor=2)
        x = self.layer4(x)
        
        x = self.conv(x)
        return x

class ResUNet(nn.Module):
    def __init__(self, in_channels, out_channels):
        super(ResUNet, self).__init__()
        self.encoder = ResNetEncoder(in_channels, out_channels)
        self.decoder = ResNetDecoder(in_channels, out_channels)
        
    def forward(self, x):
        x1, x2, x3, x4 = self.encoder(x)
        out = self.decoder(x1, x2, x3, x4)
        return out

在这个示例中，我们使用了ResNet-34结构作为编码器，并将其与U-Net结构的解码器相结合。该模型接受大小为(in_channels, H, W)的图像作为输入，并输出大小为(1, H, W)的二进制掩模。