class ActionObjectDetector(nn.Module):
    """
    动作-物体协同检测器（DAOS思路）
    
    同时检测驾驶员动作和交互物体
    双重确认降低误报率
    """
    
    def __init__(self, n_actions=15, n_objects=10):
        super().__init__()
        
        # 共享视觉编码器
        self.encoder = nn.Sequential(
            nn.Conv2d(3, 64, 3, stride=2, padding=1), nn.ReLU(),
            nn.Conv2d(64, 128, 3, stride=2, padding=1), nn.ReLU(),
            nn.AdaptiveAvgPool2d((4, 4)),
        )
        
        # 动作分类头
        self.action_head = nn.Sequential(
            nn.Linear(128*16, 256), nn.ReLU(),
            nn.Linear(256, n_actions)
        )
        
        # 物体分类头
        self.object_head = nn.Sequential(
            nn.Linear(128*16, 256), nn.ReLU(),
            nn.Linear(256, n_objects)
        )
        
        # 物体位置回归头 (x, y, w, h)
        self.bbox_head = nn.Linear(256, 4)
    
    def forward(self, x):
        feat = self.encoder(x).flatten(1)
        return {
            'action': self.action_head(feat),
            'object': self.object_head(feat),
            'bbox': self.bbox_head(feat),
        }