water_turbidity_det/train.py

# 微调pytorch的预训练模型，在自己的数据上训练，完成分类任务。
import time

import torch
import torch.nn as nn
import torch.optim as optim
from torch.utils.data import DataLoader
import torchvision.transforms as transforms
from torchvision.datasets import ImageFolder
from torchvision.models import resnet18, ResNet18_Weights,resnet50,ResNet50_Weights, squeezenet1_0, SqueezeNet1_0_Weights,\
    shufflenet_v2_x1_0, ShuffleNet_V2_X1_0_Weights, swin_v2_s, Swin_V2_S_Weights, swin_v2_b, Swin_V2_B_Weights
import matplotlib.pyplot as plt
import numpy as np
from torch.utils.tensorboard import SummaryWriter  # 添加 TensorBoard 支持
from datetime import datetime
import os
os.environ['CUDA_VISIBLE_DEVICES'] = '1'

class Trainer:
    def __init__(self, batch_size, train_dir, val_dir, name, checkpoint):
        # 初始化 TensorBoard writer
        self.name = name
        self.checkpoint = checkpoint
        # 获取当前时间戳
        timestamp = datetime.now().strftime("%Y%m%d-%H%M%S")
        log_dir = f'runs/turbidity_{self.name}_{timestamp}'
        self.writer = SummaryWriter(log_dir)

        # 定义数据增强和处理
        self.train_transforms = transforms.Compose([
            transforms.Resize((256, 256)),  # 调整图像大小为256x256 (ResNet输入尺寸)
            transforms.RandomHorizontalFlip(p=0.5),  # 随机水平翻转，增加数据多样性
            transforms.RandomRotation(10),  # 随机旋转±10度
            transforms.ColorJitter(brightness=0.1, contrast=0.1, saturation=0, hue=0),  # 颜色抖动
            transforms.ToTensor(),  # 转换为tensor并归一化到[0,1]
            transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])  # ImageNet标准化
        ])

        # 测试集基础变换
        self.val_transforms = transforms.Compose([
            transforms.Resize((256, 256)),
            transforms.ToTensor(),
            transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
        ])

        # 创建数据集对象
        self.train_dataset = ImageFolder(root=train_dir, transform=self.train_transforms)
        self.val_dataset = ImageFolder(root=val_dir, transform=self.val_transforms)

        # 创建数据加载器 (Windows环境下设置num_workers=0避免多进程问题)
        self.batch_size = batch_size
        self.train_loader = DataLoader(self.train_dataset, batch_size=batch_size, shuffle=True, num_workers=10)
        self.val_loader = DataLoader(self.val_dataset, batch_size=batch_size, shuffle=False, num_workers=10)
        # 获取类别数量
        self.num_classes = len(self.train_dataset.classes)
        print(f"发现 {self.num_classes} 个类别: {self.train_dataset.classes}")

        # 加载模型
        if name == 'resnet50':
            self.weights = ResNet50_Weights.IMAGENET1K_V2
            self.model = resnet50(weights=self.weights)
        elif name == 'squeezenet':
            self.weights = SqueezeNet1_0_Weights.IMAGENET1K_V1
            self.model = squeezenet1_0(weights=self.weights)
        elif name == 'shufflenet':
            self.weights = ShuffleNet_V2_X1_0_Weights.IMAGENET1K_V1
            self.model = shufflenet_v2_x1_0(weights=self.weights)
        elif name == 'swin_v2_s':
            self.weights = Swin_V2_S_Weights.IMAGENET1K_V1
            self.model = swin_v2_s(weights=self.weights)
        elif name == 'swin_v2_b':
            self.weights = Swin_V2_B_Weights.IMAGENET1K_V1
            self.model = swin_v2_b(weights=self.weights)
        else:
            raise ValueError(f"Invalid model name: {name}")
        print(self.model)
        # 冻结特征提取层，只训练最后几层，
        for param in self.model.parameters():
            param.requires_grad = False

        # 替换最后的分类层以适应新的分类任务
        if hasattr(self.model, 'fc'):
            # ResNet系列模型
            self.model.fc = nn.Sequential(
                nn.Linear(int(self.model.fc.in_features), int(self.model.fc.in_features) // 2, bias=True),
                nn.ReLU(inplace=True),
                nn.Dropout(0.5),
                nn.Linear(int(self.model.fc.in_features) // 2, self.num_classes, bias=False)
            )
        elif hasattr(self.model, 'classifier'):
            # Swin Transformer等模型
            self.model.classifier = nn.Sequential(
                nn.Linear(int(self.model.classifier.in_features), int(self.model.classifier.in_features) // 2,
                          bias=True),
                nn.ReLU(inplace=True),
                nn.Dropout(0.5),
                nn.Linear(int(self.model.classifier.in_features) // 2, self.num_classes, bias=False)
            )
        elif hasattr(self.model, 'head'):
            # Swin Transformer使用head层
            in_features = self.model.head.in_features
            self.model.head = nn.Sequential(
                nn.Linear(int(in_features), int(in_features) // 2, bias=True),
                nn.ReLU(inplace=True),
                nn.Dropout(0.5),
                nn.Linear(int(in_features) // 2, self.num_classes, bias=False)
            )
        else:
            raise ValueError(f"Model {name} does not have recognizable classifier layer")

        # 将模型移动到GPU
        self.device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
        self.model = self.model.to(self.device)

        # 定义损失函数
        self.loss = nn.CrossEntropyLoss()  # 多分类常用的交叉熵损失

        # 定义优化器
        # 只更新requires_grad=True的参数
        self.optimizer = optim.Adam(self.model.parameters(), lr=1e-3, weight_decay=1e-4)

        # 基于验证损失动态调整，更智能
        self.scheduler = optim.lr_scheduler.ReduceLROnPlateau(
            self.optimizer, mode='min', factor=0.5, patience=5, min_lr=1e-7
        )

    def train_model(self):
        """
        单轮训练函数

        Args:

        Returns:
            average_loss: 平均损失
            accuracy: 准确率
        """
        self.model.train()  # 设置模型为训练模式（启用dropout/batchnorm等）
        running_loss = 0.0
        correct_predictions = 0
        total_samples = 0

        # 遍历训练数据
        for inputs, labels in self.train_loader:
            # 将数据移到指定设备上
            inputs = inputs.to(self.device)
            labels = labels.to(self.device)

            # 清零梯度缓存
            self.optimizer.zero_grad()

            # 前向传播
            outputs = self.model(inputs)
            loss = self.loss(outputs, labels)

            # 反向传播
            loss.backward()

            # 更新参数
            self.optimizer.step()

            # 统计信息
            running_loss += loss.item() * inputs.size(0)
            _, predicted = torch.max(outputs.data, 1)
            total_samples += labels.size(0)
            correct_predictions += (predicted == labels).sum().item()

        epoch_loss = running_loss / len(self.train_loader.dataset)
        epoch_acc = correct_predictions / total_samples
        return epoch_loss, epoch_acc


    def validate_model(self):
        """
        验证模型性能

        Args:
        Returns:
            average_loss: 平均损失
            accuracy: 准确率
        """
        self.model.eval()  # 设置模型为评估模式（关闭dropout/batchnorm等）

        running_loss = 0.0
        correct_predictions = 0
        total_samples = 0

        # 不计算梯度，提高推理速度
        with torch.no_grad():
            for inputs, labels in self.val_loader:
                inputs = inputs.to(self.device)
                labels = labels.to(self.device)

                outputs = self.model(inputs)
                loss = self.loss(outputs, labels)

                running_loss += loss.item() * inputs.size(0)
                _, predicted = torch.max(outputs.data, 1)
                total_samples += labels.size(0)
                correct_predictions += (predicted == labels).sum().item()

        epoch_loss = running_loss / len(self.val_loader.dataset)
        epoch_acc = correct_predictions / total_samples

        return epoch_loss, epoch_acc


    def train_and_validate(self, num_epochs=25):
        """
        训练和验证

        Args:
            num_epochs: 训练轮数

        Returns:
            train_losses: 每轮训练损失
            train_accuracies: 每轮训练准确率
            val_losses: 每轮验证损失
            val_accuracies: 每轮验证准确率
        """
        # 存储训练过程中的指标
        train_losses = []
        train_accuracies = []
        val_losses = []
        val_accuracies = []

        best_val_acc = 0.0
        best_val_loss = float('inf')

        print("开始训练...")
        for epoch in range(num_epochs):
            print(f'Epoch {epoch + 1}/{num_epochs}')
            print('-' * 20)

            # 训练阶段
            train_loss, train_acc = self.train_model()
            print(f'Train Loss: {train_loss:.4f} Acc: {train_acc:.4f}')

            # 验证阶段
            val_loss, val_acc = self.validate_model()
            print(f'Val Loss: {val_loss:.4f} Acc: {val_acc:.4f}')

            # 学习率调度
            self.scheduler.step(val_loss)

            # 记录指标到 TensorBoard
            self.writer.add_scalar('Loss/Train', train_loss, epoch)
            self.writer.add_scalar('Loss/Validation', val_loss, epoch)
            self.writer.add_scalar('Accuracy/Train', train_acc, epoch)
            self.writer.add_scalar('Accuracy/Validation', val_acc, epoch)
            self.writer.add_scalar('Learning Rate', self.scheduler.get_last_lr()[0], epoch)

            # 记录指标
            train_losses.append(train_loss)
            train_accuracies.append(train_acc)
            val_losses.append(val_loss)
            val_accuracies.append(val_acc)

            # 保存最佳模型 (基于验证准确率)
            if val_acc > best_val_acc:
                best_val_acc = val_acc
                torch.save(self.model.state_dict(), f'{self.name}_best_model_acc.pth')
                print(f"保存了新的最佳准确率模型，验证准确率: {best_val_acc:.4f}")
            
            # 保存最低验证损失模型
            
            if val_loss < best_val_loss:
                best_val_loss = val_loss
                torch.save(self.model.state_dict(), f'{self.name}_best_model_loss.pth')
                print(f"保存了新的最低损失模型，验证损失: {best_val_loss:.4f}")


        # 关闭 TensorBoard writer
        self.writer.close()
        
        print(f"训练完成! 最佳验证准确率: {best_val_acc:.4f}, 最低验证损失: {best_val_loss:.4f}")
        return train_losses, train_accuracies, val_losses, val_accuracies

if __name__ == '__main__':
    # 开始训练
    import argparse
    parser = argparse.ArgumentParser('预训练模型调参')
    parser.add_argument('--train_dir',default='./label_data/train',help='help')
    parser.add_argument('--val_dir', default='./label_data/test',help='help')
    parser.add_argument('--model', default='resnet18',help='help')
    args = parser.parse_args()
    num_epochs = 100
    trainer = Trainer(batch_size=64,
                      train_dir=args.train_dir,
                      val_dir=args.val_dir,
                      name=args.model,
                      checkpoint=False)
    train_losses, train_accuracies, val_losses, val_accuracies = trainer.train_and_validate(num_epochs)