refactor: replace custom Bottleneck model with standard ResNet-34 + Dropout

This commit is contained in:
yukun-hh 2026-05-12 15:56:28 +08:00
parent cb17be247e
commit 4575f3390f
2 changed files with 47 additions and 79 deletions

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@ -1,6 +1,5 @@
"""
模型定义文件 - 使用瓶颈结构 (Bottleneck) 的深度残差网络
目标约50层参数量约80M
模型定义文件 - ResNet-34
author : yukun-hh
date : 2026-4-10
"""
@ -10,27 +9,19 @@ from torch.nn import functional as F
from torchsummary import summary
class Bottleneck(nn.Module):
class BasicBlock(nn.Module):
"""
瓶颈残差块1x1(降维) -> 3x3 -> 1x1(升维)
若需要下采样或通道变化则在跳跃连接中使用1x1卷积
ResNet-34 基础残差块3x3 -> 3x3
若需要下采样或通道变化则在跳跃连接中使用 1x1 卷积
"""
expansion = 4 # 输出通道是中间通道的4倍
expansion = 1
def __init__(self, in_channels, mid_channels, stride=1, downsample=None):
"""
:param in_channels: 输入通道数
:param mid_channels: 中间层通道数1x1降维后的通道数
:param stride: 步长用于下采样
:param downsample: 下采样模块当stride1或通道变化时使用
"""
def __init__(self, in_channels, out_channels, stride=1, downsample=None):
super().__init__()
self.conv1 = nn.Conv2d(in_channels, mid_channels, kernel_size=1, bias=False)
self.bn1 = nn.BatchNorm2d(mid_channels)
self.conv2 = nn.Conv2d(mid_channels, mid_channels, kernel_size=3, stride=stride, padding=1, bias=False)
self.bn2 = nn.BatchNorm2d(mid_channels)
self.conv3 = nn.Conv2d(mid_channels, mid_channels * self.expansion, kernel_size=1, bias=False)
self.bn3 = nn.BatchNorm2d(mid_channels * self.expansion)
self.conv1 = nn.Conv2d(in_channels, out_channels, kernel_size=3, stride=stride, padding=1, bias=False)
self.bn1 = nn.BatchNorm2d(out_channels)
self.conv2 = nn.Conv2d(out_channels, out_channels, kernel_size=3, stride=1, padding=1, bias=False)
self.bn2 = nn.BatchNorm2d(out_channels)
self.relu = nn.ReLU(inplace=True)
self.downsample = downsample
@ -43,10 +34,6 @@ class Bottleneck(nn.Module):
out = self.conv2(out)
out = self.bn2(out)
out = self.relu(out)
out = self.conv3(out)
out = self.bn3(out)
if self.downsample is not None:
identity = self.downsample(x)
@ -57,68 +44,49 @@ class Bottleneck(nn.Module):
class Net(nn.Module):
"""
基于 Bottleneck ResNet 风格模型
各阶段配置仿照 ResNet-50适当调整宽度以达到约80M参数
"""
def __init__(self, num_classes=4):
def __init__(self, num_classes=4, dropout=0.5):
super().__init__()
# 第一阶段7x7卷积 + 最大池化
self.conv1 = nn.Conv2d(3, 64, kernel_size=7, stride=2, padding=3, bias=False)
self.bn1 = nn.BatchNorm2d(64)
self.relu = nn.ReLU(inplace=True)
self.maxpool = nn.MaxPool2d(kernel_size=3, stride=2, padding=1)
# 残差阶段定义
# 每个阶段的参数:[块数, 中间通道数, 步长]
# 为了达到80M参数我们略微加宽网络相比标准ResNet-50
layers_config = [
(3, 64, 1), # stage2: 3个瓶颈块输出通道 64*4=256
(4, 128, 2), # stage3: 4个瓶颈块输出通道 128*4=512
(14, 256, 2), # stage4: 14个瓶颈块输出通道 256*4=1024加深至此阶段
(3, 512, 2) # stage5: 3个瓶颈块输出通道 512*4=2048
(3, 64, 1), # layer1
(4, 128, 2), # layer2
(6, 256, 2), # layer3
(3, 512, 2), # layer4
]
self.in_channels = 64
self.stage2 = self._make_layer(layers_config[0])
self.stage3 = self._make_layer(layers_config[1])
self.stage4 = self._make_layer(layers_config[2])
self.stage5 = self._make_layer(layers_config[3])
self.layer1 = self._make_layer(layers_config[0])
self.layer2 = self._make_layer(layers_config[1])
self.layer3 = self._make_layer(layers_config[2])
self.layer4 = self._make_layer(layers_config[3])
# 全局池化与分类层
self.avgpool = nn.AdaptiveAvgPool2d((1, 1))
self.fc = nn.Linear(2048, num_classes)
self.dropout = nn.Dropout(dropout)
self.fc = nn.Linear(512, num_classes)
def _make_layer(self, config):
"""
构建一个残差阶段
:param config: (块数, 中间通道数, 第一阶段步长)
:return: nn.Sequential
"""
num_blocks, mid_channels, stride = config
num_blocks, out_channels, stride = config
downsample = None
layers = []
# 第一个块可能需要下采样和通道匹配
if stride != 1 or self.in_channels != mid_channels * Bottleneck.expansion:
if stride != 1 or self.in_channels != out_channels:
downsample = nn.Sequential(
nn.Conv2d(self.in_channels, mid_channels * Bottleneck.expansion,
nn.Conv2d(self.in_channels, out_channels,
kernel_size=1, stride=stride, bias=False),
nn.BatchNorm2d(mid_channels * Bottleneck.expansion),
nn.BatchNorm2d(out_channels),
)
layers.append(
Bottleneck(self.in_channels, mid_channels, stride, downsample)
)
self.in_channels = mid_channels * Bottleneck.expansion
layers.append(BasicBlock(self.in_channels, out_channels, stride, downsample))
self.in_channels = out_channels
# 后续块
for _ in range(1, num_blocks):
layers.append(
Bottleneck(self.in_channels, mid_channels)
)
layers.append(BasicBlock(self.in_channels, out_channels))
return nn.Sequential(*layers)
@ -128,13 +96,14 @@ class Net(nn.Module):
x = self.relu(x)
x = self.maxpool(x)
x = self.stage2(x)
x = self.stage3(x)
x = self.stage4(x)
x = self.stage5(x)
x = self.layer1(x)
x = self.layer2(x)
x = self.layer3(x)
x = self.layer4(x)
x = self.avgpool(x)
x = torch.flatten(x, 1)
x = self.dropout(x)
x = self.fc(x)
return x

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@ -4,7 +4,7 @@
> 同济大学 Python 人工智能程序设计课程小组作业
基于自定义 ResNet 风格 Bottleneck 架构的 CNN 模型(约 80M 参数),将生活垃圾分为厨余垃圾、可回收物、其他垃圾、有害垃圾四个类别,输入为 256×256 RGB 图像。
基于 ResNet-34 架构的 CNN 模型(约 21M 参数),将生活垃圾分为厨余垃圾、可回收物、其他垃圾、有害垃圾四个类别,输入为 256×256 RGB 图像。
---
@ -25,7 +25,7 @@
## 项目特点
- **四类垃圾分类**厨余垃圾1、可回收物2、其他垃圾3、有害垃圾4
- **自定义 ResNet Bottleneck 架构**:约 80M 参数50 层深度残差网络
- **ResNet-34 架构**:约 21M 参数34 层深度残差网络,含 Dropout 正则化
- **数据增强**:训练时使用随机裁剪、水平翻转、旋转、色彩抖动
- **Macro-F1 评估**:采用宏平均 F1 分数作为主要评估指标,兼顾各类别表现
- **类别加权损失**:自动计算类别权重,缓解类别不平衡问题
@ -35,28 +35,27 @@
## 模型架构
模型基于残差网络ResNet的 Bottleneck 构建块设计
模型基于标准 ResNet-34 架构,使用 BasicBlock 构建
### Bottleneck 块
### BasicBlock 块
每个 Bottleneck 块包含三个卷积层
每个 BasicBlock 包含两个 3x3 卷积层 + 跳跃连接
| 层 | 卷积 | 作用 |
|---|---|---|
| 1x1 Conv | 降维 | 减少通道数,降低计算量 |
| 3x3 Conv | 特征提取 | 核心卷积操作 |
| 1x1 Conv | 升维 (x4) | 恢复通道数至输入的 4 倍 |
| 3x3 Conv | 特征提取 | 第一层卷积 |
| 3x3 Conv | 特征提取 | 第二层卷积 |
### 网络结构
| 阶段 | 块数 | 输出通道数 | 说明 |
|---|---|---|---|
| 初始层 | - | 64 | 7x7 Conv, stride=2 + MaxPool |
| Stage 1 | 3 | 256 | 第一个残差阶段 |
| Stage 2 | 4 | 512 | - |
| Stage 3 | 14 | 1024 | 最深阶段(比 ResNet-50 加深) |
| Stage 4 | 3 | 2048 | 最终残差阶段 |
| 分类头 | - | 4 | 全局平均池化 + 全连接层 |
| Layer1 | 3 | 64 | 第一个残差阶段 |
| Layer2 | 4 | 128 | - |
| Layer3 | 6 | 256 | - |
| Layer4 | 3 | 512 | 最终残差阶段 |
| 分类头 | - | 4 | 全局平均池化 + Dropout + 全连接层 |
## 数据集
@ -111,7 +110,7 @@
|---|---|
| `Train.py` | 训练主脚本,包含训练循环、验证、评估 |
| `Dataloader.py` | 数据加载模块,包含 RobustImageFolder 和 DataLoader 创建 |
| `Model.py` | 模型定义,Bottleneck 残差块 + Net 主模型 |
| `Model.py` | 模型定义,ResNet-34BasicBlock+ Dropout |
| `Merge_classes.py` | 数据集预处理265 类合并为 4 类 |
| `best_model.pth` | 训练好的最佳模型权重(约 125 MB |
| `AGENTS.md` | AI 助手指南(开发辅助) |