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| import torch import torch.nn as nn import torch.nn.functional as F from typing import Optional, Tuple
class DrowsinessTransformer(nn.Module): """ 基于Transformer的疲劳检测模型 复现Nature 2025论文方法 """ def __init__(self, config: dict): super().__init__() self.img_size = config.get('img_size', 224) self.patch_size = config.get('patch_size', 16) self.num_frames = config.get('num_frames', 16) self.embed_dim = config.get('embed_dim', 768) self.num_heads = config.get('num_heads', 12) self.num_layers = config.get('num_layers', 12) self.dropout = config.get('dropout', 0.1) self.patch_embed = PatchEmbedding( img_size=self.img_size, patch_size=self.patch_size, in_channels=3, embed_dim=self.embed_dim ) num_patches = (self.img_size // self.patch_size) ** 2 self.pos_embed = nn.Parameter( torch.zeros(1, num_patches + 1, self.embed_dim) ) self.temporal_embed = nn.Parameter( torch.zeros(1, self.num_frames, self.embed_dim) ) self.temporal_encoder = nn.ModuleList([ TemporalTransformerBlock( embed_dim=self.embed_dim, num_heads=self.num_heads, dropout=self.dropout ) for _ in range(self.num_layers // 2) ]) self.spatial_encoder = nn.ModuleList([ SpatialTransformerBlock( embed_dim=self.embed_dim, num_heads=self.num_heads, dropout=self.dropout ) for _ in range(self.num_layers // 2) ]) self.classification_head = nn.Sequential( nn.LayerNorm(self.embed_dim), nn.Linear(self.embed_dim, 512), nn.GELU(), nn.Dropout(self.dropout), nn.Linear(512, 2) ) self.regression_head = nn.Sequential( nn.LayerNorm(self.embed_dim), nn.Linear(self.embed_dim, 256), nn.GELU(), nn.Dropout(self.dropout), nn.Linear(256, 1), nn.Sigmoid() ) self._init_weights() def _init_weights(self): """初始化权重""" nn.init.trunc_normal_(self.pos_embed, std=0.02) nn.init.trunc_normal_(self.temporal_embed, std=0.02) def forward(self, x: torch.Tensor) -> Tuple[torch.Tensor, torch.Tensor]: """ 前向传播 Args: x: 输入视频序列, shape=(B, T, C, H, W) Returns: logits: 分类logits, shape=(B, 2) drowsiness_score: 疲劳程度分数, shape=(B, 1) """ B, T, C, H, W = x.shape x = x.view(B * T, C, H, W) x = self.patch_embed(x) x = x + self.pos_embed[:, 1:, :] cls_tokens = self.pos_embed[:, 0, :].unsqueeze(1).expand(B * T, -1, -1) x = torch.cat([cls_tokens, x], dim=1) x = x.view(B, T, -1, self.embed_dim) x = x + self.temporal_embed.unsqueeze(2) for temporal_block in self.temporal_encoder: x = temporal_block(x) for spatial_block in self.spatial_encoder: x = spatial_block(x) x = x[:, :, 0, :].mean(dim=1) logits = self.classification_head(x) drowsiness_score = self.regression_head(x) return logits, drowsiness_score
class PatchEmbedding(nn.Module): """ 图像分块嵌入 将图像分割为patch并嵌入到向量空间 """ def __init__(self, img_size: int = 224, patch_size: int = 16, in_channels: int = 3, embed_dim: int = 768): super().__init__() self.img_size = img_size self.patch_size = patch_size self.num_patches = (img_size // patch_size) ** 2 self.proj = nn.Conv2d( in_channels, embed_dim, kernel_size=patch_size, stride=patch_size ) def forward(self, x: torch.Tensor) -> torch.Tensor: """ Args: x: (B, C, H, W) Returns: (B, N, D) where N = num_patches """ x = self.proj(x) x = x.flatten(2).transpose(1, 2) return x
class TemporalTransformerBlock(nn.Module): """ 时序Transformer块 在时间维度上进行自注意力计算 """ def __init__(self, embed_dim: int = 768, num_heads: int = 12, mlp_ratio: float = 4.0, dropout: float = 0.1): super().__init__() self.norm1 = nn.LayerNorm(embed_dim) self.attn = nn.MultiheadAttention( embed_dim, num_heads, dropout=dropout, batch_first=True ) self.norm2 = nn.LayerNorm(embed_dim) mlp_hidden_dim = int(embed_dim * mlp_ratio) self.mlp = nn.Sequential( nn.Linear(embed_dim, mlp_hidden_dim), nn.GELU(), nn.Dropout(dropout), nn.Linear(mlp_hidden_dim, embed_dim), nn.Dropout(dropout) ) def forward(self, x: torch.Tensor) -> torch.Tensor: """ Args: x: (B, T, N, D) Returns: (B, T, N, D) """ B, T, N, D = x.shape x_flat = x.permute(0, 2, 1, 3).reshape(B * N, T, D) x_norm = self.norm1(x_flat) attn_out, _ = self.attn(x_norm, x_norm, x_norm) x_flat = x_flat + attn_out x_flat = x_flat + self.mlp(self.norm2(x_flat)) x = x_flat.view(B, N, T, D).permute(0, 2, 1, 3) return x
class SpatialTransformerBlock(nn.Module): """ 空间Transformer块 在空间维度上进行自注意力计算 """ def __init__(self, embed_dim: int = 768, num_heads: int = 12, mlp_ratio: float = 4.0, dropout: float = 0.1): super().__init__() self.norm1 = nn.LayerNorm(embed_dim) self.attn = nn.MultiheadAttention( embed_dim, num_heads, dropout=dropout, batch_first=True ) self.norm2 = nn.LayerNorm(embed_dim) mlp_hidden_dim = int(embed_dim * mlp_ratio) self.mlp = nn.Sequential( nn.Linear(embed_dim, mlp_hidden_dim), nn.GELU(), nn.Dropout(dropout), nn.Linear(mlp_hidden_dim, embed_dim), nn.Dropout(dropout) ) def forward(self, x: torch.Tensor) -> torch.Tensor: """ Args: x: (B, T, N, D) Returns: (B, T, N, D) """ B, T, N, D = x.shape x_flat = x.reshape(B * T, N, D) x_norm = self.norm1(x_flat) attn_out, _ = self.attn(x_norm, x_norm, x_norm) x_flat = x_flat + attn_out x_flat = x_flat + self.mlp(self.norm2(x_flat)) x = x_flat.view(B, T, N, D) return x
if __name__ == "__main__": config = { 'img_size': 224, 'patch_size': 16, 'num_frames': 16, 'embed_dim': 768, 'num_heads': 12, 'num_layers': 12, 'dropout': 0.1 } model = DrowsinessTransformer(config) x = torch.randn(2, 16, 3, 224, 224) logits, drowsiness_score = model(x) print(f"输入形状: {x.shape}") print(f"分类输出: {logits.shape}") print(f"疲劳分数: {drowsiness_score.shape}") total_params = sum(p.numel() for p in model.parameters()) print(f"总参数量: {total_params / 1e6:.2f}M")
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