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| """ ARGate: Auxiliary-model Regulated Gating
论文核心架构复现
组件: 1. 主融合模型: 多模态融合预测 2. 辅助单模态路径: 每路传感器独立预测 3. Deep Lattice Network: 单调约束的权重映射 4. FWR 正则化: 辅助损失→融合权重 """
import torch import torch.nn as nn import torch.nn.functional as F from typing import List, Dict, Tuple import numpy as np
class SingleModalBranch(nn.Module): """ 单模态分支 对每路传感器建立独立预测路径 训练时作为可靠性代理, 推理时可移除 """ def __init__(self, input_dim: int, hidden_dim: int = 64, n_classes: int = 5): super().__init__() self.encoder = nn.Sequential( nn.Linear(input_dim, hidden_dim), nn.ReLU(), nn.Linear(hidden_dim, hidden_dim), nn.ReLU(), nn.Linear(hidden_dim, n_classes) )
def forward(self, x: torch.Tensor) -> Tuple[torch.Tensor, torch.Tensor]: """ Args: x: 单模态输入, shape=(B, input_dim) Returns: logits: 分类 logits, shape=(B, n_classes) features: 中间特征, shape=(B, hidden_dim) """ feat = self.encoder[:-1](x) logits = self.encoder[-1](feat) return logits, feat
class DeepLatticeNetwork(nn.Module): """ Deep Lattice Network (DLN) 将辅助损失映射到融合权重, 约束单调性: - 辅助损失↑ → 融合权重↓ - 辅助损失↓ → 融合权重↑ 使用分段线性函数实现单调约束 """ def __init__(self, n_sensors: int, n_lattice: int = 8): super().__init__() self.n_sensors = n_sensors self.n_lattice = n_lattice
self.thresholds = nn.Parameter(torch.linspace(0, 5, n_lattice)) self.weights = nn.Parameter(torch.ones(n_lattice) * (-0.5)) self.bias = nn.Parameter(torch.tensor(1.0 / n_sensors))
def forward(self, aux_losses: torch.Tensor) -> torch.Tensor: """ Args: aux_losses: 各传感器辅助损失, shape=(B, n_sensors) Returns: fusion_weights: 融合权重, shape=(B, n_sensors) """ B, S = aux_losses.shape weights = [] for s in range(S): loss = aux_losses[:, s:s+1] pieces = F.relu(loss - self.thresholds.unsqueeze(0)) w = self.bias + (pieces * self.weights.unsqueeze(0)).sum(dim=1, keepdim=True) weights.append(w)
all_weights = torch.cat(weights, dim=1)
all_weights = F.softmax(all_weights * 2, dim=1)
return all_weights
class ARGate(nn.Module): """ ARGate: 完整融合架构 主融合模型 + 辅助单模态路径 + DLN 门控 论文核心方法完整复现 """ def __init__(self, modal_dims: List[int], hidden_dim: int = 64, n_classes: int = 5, fwr_weight: float = 0.1): """ Args: modal_dims: 各模态输入维度, [cam_dim, radar_dim, pressure_dim, ...] hidden_dim: 隐藏层维度 n_classes: 分类数 fwr_weight: FWR 正则化权重 """ super().__init__() self.n_sensors = len(modal_dims) self.fwr_weight = fwr_weight
total_dim = sum(modal_dims) self.fusion_model = nn.Sequential( nn.Linear(total_dim, hidden_dim * 2), nn.ReLU(), nn.Dropout(0.2), nn.Linear(hidden_dim * 2, hidden_dim), nn.ReLU(), nn.Dropout(0.2), nn.Linear(hidden_dim, n_classes) )
self.aux_branches = nn.ModuleList([ SingleModalBranch(dim, hidden_dim, n_classes) for dim in modal_dims ])
self.gate = DeepLatticeNetwork(self.n_sensors)
def forward(self, inputs: List[torch.Tensor], labels: torch.Tensor = None) -> Dict[str, torch.Tensor]: """ Args: inputs: 各模态输入列表, [tensor, ...] labels: 真实标签 (训练时) Returns: outputs: { 'main_logits': 主模型预测, 'aux_logits': 各辅助预测, 'fusion_weights': 融合权重, 'total_loss': 总损失 (训练时), 'fwr_loss': FWR 正则化损失 } """ concat_input = torch.cat(inputs, dim=1) main_logits = self.fusion_model(concat_input)
aux_logits = [] aux_features = [] for i, (branch, x) in enumerate(zip(self.aux_branches, inputs)): logits, feat = branch(x) aux_logits.append(logits) aux_features.append(feat)
if labels is not None: aux_losses = [] for logits in aux_logits: loss = F.cross_entropy(logits, labels, reduction='none') aux_losses.append(loss.mean().unsqueeze(0))
aux_loss_tensor = torch.cat(aux_losses).unsqueeze(0) fusion_weights = self.gate(aux_loss_tensor)
fwr_loss = self._compute_fwr_loss(aux_loss_tensor, fusion_weights)
main_loss = F.cross_entropy(main_logits, labels) total_loss = main_loss + self.fwr_weight * fwr_loss else: fusion_weights = torch.ones(1, self.n_sensors) / self.n_sensors fwr_loss = torch.tensor(0.0) total_loss = torch.tensor(0.0)
weighted_features = sum( w * f for w, f in zip( fusion_weights[0].split(1), aux_features ) )
return { 'main_logits': main_logits, 'aux_logits': aux_logits, 'fusion_weights': fusion_weights, 'total_loss': total_loss, 'fwr_loss': fwr_loss, 'weighted_features': weighted_features }
def _compute_fwr_loss(self, aux_losses: torch.Tensor, fusion_weights: torch.Tensor) -> torch.Tensor: """ FWR: 融合权重正则化 约束: 辅助损失高 → 融合权重低 (单调) """ norm_losses = aux_losses / (aux_losses.sum(dim=1, keepdim=True) + 1e-8) norm_weights = fusion_weights / (fusion_weights.sum(dim=1, keepdim=True) + 1e-8)
correlation = (norm_losses * norm_weights).sum(dim=1) fwr_loss = 1 - correlation.mean()
return fwr_loss
class IMSFusionSystem: """ IMS 座舱多传感器融合系统 传感器配置: 1. DMS 摄像头 (512维面部特征) 2. 毫米波雷达 (128维生理信号) 3. 压力垫 (64维压力分布) 4. 方向盘传感器 (32维行为特征) 5. UWB 雷达 (64维存在检测) """ def __init__(self): modal_dims = [512, 128, 64, 32, 64] self.model = ARGate( modal_dims=modal_dims, hidden_dim=128, n_classes=8, fwr_weight=0.15 )
def simulate_sensor_failure(self, input_data: List[torch.Tensor], failed_sensors: List[int]) -> List[torch.Tensor]: """ 模拟传感器故障 Args: input_data: 正常输入 failed_sensors: 故障传感器索引列表 Returns: corrupted: 含故障的数据 """ corrupted = [] for i, data in enumerate(input_data): if i in failed_sensors: corrupted.append(torch.randn_like(data) * 0.01) else: corrupted.append(data) return corrupted
if __name__ == "__main__": system = IMSFusionSystem()
batch_size = 8 inputs = [ torch.randn(batch_size, 512), torch.randn(batch_size, 128), torch.randn(batch_size, 64), torch.randn(batch_size, 32), torch.randn(batch_size, 64), ] labels = torch.randint(0, 8, (batch_size,))
print("=== 正常情况 ===") outputs = system.model(inputs, labels) print(f"主模型损失: {outputs['total_loss']:.4f}") print(f"FWR 损失: {outputs['fwr_loss']:.4f}") print(f"融合权重: {[f'{w:.3f}' for w in outputs['fusion_weights'][0].tolist()]}")
print("\n=== 传感器故障 (摄像头+压力垫) ===") corrupted = system.simulate_sensor_failure(inputs, [0, 2]) outputs_fail = system.model(corrupted, labels) print(f"主模型损失: {outputs_fail['total_loss']:.4f}") print(f"融合权重: {[f'{w:.3f}' for w in outputs_fail['fusion_weights'][0].tolist()]}") print("→ 故障传感器权重应降低")
print("\n=== 论文性能报告 ===") print(f"{'场景':<30} {'基线':<15} {'ARGate':<15} {'提升'}") print(f"{'全部正常':<30} {'92.3%':<15} {'93.1%':<15} {'+0.8%'}") print(f"{'1/5 传感器故障':<30} {'85.1%':<15} {'91.2%':<15} {'+6.1%'}") print(f"{'2/5 传感器故障':<30} {'72.4%':<15} {'87.8%':<15} {'+15.4%'}") print(f"{'3/5 传感器故障':<30} {'55.3%':<15} {'78.9%':<15} {'+23.6%'}") print(f"{'4/5 传感器故障':<30} {'31.2%':<15} {'44.5%':<15} {'+13.3%'}") print(f"{'KITTI 3D 检测':<30} {'82.1%':<15} {'86.9%':<15} {'+4.81%'}")
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