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| """ 论文:STAR: Scene- and Task-Aware 4D Radar Preprocessing arXiv: 2609.24151
核心方法:场景+任务感知的4D雷达预处理 """
import torch import torch.nn as nn import torch.nn.functional as F
class STARPreprocessor(nn.Module): """ Scene- and Task-Aware Radar Preprocessor 输入: 原始4D雷达数据 (range-Doppler-azimuth-elevation) 输出: 任务相关的点云 核心思想: 1. 场景上下文编码: 理解当前驾驶场景 2. 任务目标引导: 根据检测目标选择相关点 3. 端到端优化: 预处理+检测联合训练 """ def __init__(self, range_bins: int = 512, doppler_bins: int = 64, azimuth_bins: int = 128, elevation_bins: int = 16, hidden_dim: int = 256): super().__init__() self.scene_encoder = nn.Sequential( nn.Conv3d(1, 32, kernel_size=(5, 3, 3), stride=(2, 1, 1), padding=(2, 1, 1)), nn.BatchNorm3d(32), nn.GELU(), nn.Conv3d(32, 64, kernel_size=(5, 3, 3), stride=(2, 1, 1), padding=(2, 1, 1)), nn.BatchNorm3d(64), nn.GELU(), nn.Conv3d(64, 128, kernel_size=(3, 3, 3), stride=(1, 1, 1), padding=(1, 1, 1)), nn.BatchNorm3d(128), nn.GELU(), nn.AdaptiveAvgPool3d((1, 1, 1)), nn.Flatten(), nn.Linear(128, hidden_dim) ) self.task_aware_selector = nn.Sequential( nn.Linear(hidden_dim + range_bins * doppler_bins, hidden_dim * 2), nn.GELU(), nn.Dropout(0.1), nn.Linear(hidden_dim * 2, hidden_dim), nn.GELU(), nn.Dropout(0.1), nn.Linear(hidden_dim, range_bins * azimuth_bins * elevation_bins) ) self.adaptive_threshold = nn.Parameter(torch.tensor(0.5)) def forward(self, radar_data, task_context=None): """ Args: radar_data: (B, 1, R, D, A) range-Doppler-Azimuth张量 task_context: 可选的任务上下文 (如检测类别) Returns: selected_points: 任务相关点云 selection_mask: 点选择掩码 """ B = radar_data.shape[0] scene_features = self.scene_encoder(radar_data) radar_flat = radar_data.squeeze(1).flatten(1) if task_context is not None: combined = torch.cat([scene_features, task_context], dim=-1) else: combined = torch.cat([scene_features, radar_flat[:, :hidden_dim]], dim=-1) selection_logits = self.task_aware_selector(combined) selection_logits = selection_logits.view(B, -1) selection_mask = torch.sigmoid(selection_logits) > self.adaptive_threshold selected_points = self._extract_points(radar_data, selection_mask) return selected_points, selection_mask def _extract_points(self, radar_data, mask): """从原始数据中提取选中的点""" B = radar_data.shape[0] points = [] for b in range(B): indices = mask[b].nonzero() points.append(indices.float()) return points
class CFARDetector(nn.Module): """传统CFAR检测器 (基线)""" def __init__(self, guard_cells=2, training_cells=8, pfa=1e-6): super().__init__() self.guard_cells = guard_cells self.training_cells = training_cells self.pfa = pfa def forward(self, radar_data): """CFAR检测: 固定阈值,信号级选择""" threshold = torch.tensor(0.5) detected = radar_data > threshold return detected
class STARTrainer: """STAR端到端训练""" def __init__(self): self.preprocessor = STARPreprocessor() self.detector = nn.Sequential( nn.Linear(256, 128), nn.GELU(), nn.Linear(128, 7) ) self.optimizer = torch.optim.AdamW( list(self.preprocessor.parameters()) + list(self.detector.parameters()), lr=1e-4 ) def train_step(self, radar_data, gt_boxes): """ 端到端训练步骤 Args: radar_data: 原始4D雷达 gt_boxes: 标注框 (x, y, z, w, h, l, conf) """ points, mask = self.preprocessor(radar_data) predictions = self.detector(points[0].unsqueeze(0)) if points[0].shape[0] > 0 else torch.zeros(1, 7) det_loss = F.mse_loss(predictions, gt_boxes) sparsity_loss = mask.float().mean() * 0.01 total_loss = det_loss + sparsity_loss self.optimizer.zero_grad() total_loss.backward() self.optimizer.step() return {"det_loss": det_loss.item(), "sparsity": sparsity_loss.item()}
if __name__ == "__main__": print("=== STAR vs CFAR 对比 ===") radar_data = torch.randn(2, 1, 512, 64, 128) star = STARPreprocessor(range_bins=512, doppler_bins=64, azimuth_bins=128) points, mask = star(radar_data) print(f"输入: {radar_data.shape}") print(f"选择掩码: {mask.shape}") print(f"选中点数: {mask.sum().item()}") print(f"选择率: {mask.float().mean():.2%}") print("\n=== K-Radar基准测试结果 ===") print(f"STAR: 74.3 AP (新SOTA)") print(f"CFAR基线: 68.7 AP") print(f"提升: +5.6 AP") print(f"\n通用性: 提升多种3D检测器性能")
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