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| """ BEV (Bird's Eye View) 融合表示模块 将摄像头和雷达数据统一到鸟瞰图表示 """
import torch import torch.nn as nn import torch.nn.functional as F import numpy as np from typing import Tuple, Optional
class BEVFeatureExtractor(nn.Module): """ BEV特征提取器 将摄像头图像特征转换为BEV表示 """ def __init__( self, image_size: Tuple[int, int] = (1080, 1920), bev_size: Tuple[int, int] = (200, 200), bev_range: Tuple[float, float, float, float] = (-50, 50, -50, 50), feature_dim: int = 64 ): """ Args: image_size: 图像尺寸 (H, W) bev_size: BEV尺寸 (H, W) bev_range: BEV范围 (x_min, x_max, y_min, y_max) feature_dim: 特征维度 """ super().__init__() self.image_size = image_size self.bev_size = bev_size self.bev_range = bev_range self.feature_dim = feature_dim self.image_encoder = nn.Sequential( nn.Conv2d(3, 32, kernel_size=7, stride=2, padding=3), nn.BatchNorm2d(32), nn.ReLU(inplace=True), nn.Conv2d(32, 64, kernel_size=3, stride=2, padding=1), nn.BatchNorm2d(64), nn.ReLU(inplace=True), nn.Conv2d(64, feature_dim, kernel_size=3, stride=1, padding=1), nn.BatchNorm2d(feature_dim), nn.ReLU(inplace=True) ) self.depth_head = nn.Sequential( nn.Conv2d(feature_dim, 32, kernel_size=3, padding=1), nn.ReLU(inplace=True), nn.Conv2d(32, 1, kernel_size=1) ) self.bev_projection = nn.Sequential( nn.Conv2d(feature_dim + 1, feature_dim, kernel_size=3, padding=1), nn.BatchNorm2d(feature_dim), nn.ReLU(inplace=True) ) def forward( self, images: torch.Tensor, depth_gt: Optional[torch.Tensor] = None ) -> torch.Tensor: """ Args: images: (batch, 3, H, W) depth_gt: (batch, H, W) 深度真值(可选) Returns: bev_features: (batch, feature_dim, bev_H, bev_W) """ batch = images.size(0) image_features = self.image_encoder(images) depth_pred = self.depth_head(image_features).squeeze(1) combined = torch.cat([ image_features, depth_pred.unsqueeze(1) ], dim=1) bev_features = self.bev_projection(combined) bev_features = F.interpolate( bev_features, size=self.bev_size, mode='bilinear', align_corners=False ) return bev_features, depth_pred
class RadarBEVEncoder(nn.Module): """ 雷达BEV编码器 将雷达点云转换为BEV表示 """ def __init__( self, bev_size: Tuple[int, int] = (200, 200), bev_range: Tuple[float, float, float, float] = (-50, 50, -50, 50), feature_dim: int = 64 ): super().__init__() self.bev_size = bev_size self.bev_range = bev_range self.feature_dim = feature_dim self.point_encoder = nn.Sequential( nn.Linear(5, 32), nn.ReLU(inplace=True), nn.Linear(32, feature_dim), nn.ReLU(inplace=True) ) self.bev_conv = nn.Sequential( nn.Conv2d(feature_dim, feature_dim, kernel_size=3, padding=1), nn.BatchNorm2d(feature_dim), nn.ReLU(inplace=True), nn.Conv2d(feature_dim, feature_dim, kernel_size=3, padding=1), nn.BatchNorm2d(feature_dim), nn.ReLU(inplace=True) ) def forward( self, radar_points: torch.Tensor ) -> torch.Tensor: """ Args: radar_points: (batch, N, 5) x, y, z, velocity, rcs Returns: bev_features: (batch, feature_dim, bev_H, bev_W) """ batch = radar_points.size(0) N = radar_points.size(1) point_features = self.point_encoder(radar_points) bev_grid = torch.zeros( batch, self.feature_dim, *self.bev_size, device=radar_points.device ) x = radar_points[:, :, 0] y = radar_points[:, :, 1] x_min, x_max, y_min, y_max = self.bev_range bev_x = ((x - x_min) / (x_max - x_min) * self.bev_size[1]).long() bev_y = ((y - y_min) / (y_max - y_min) * self.bev_size[0]).long() valid_mask = ( (bev_x >= 0) & (bev_x < self.bev_size[1]) & (bev_y >= 0) & (bev_y < self.bev_size[0]) ) for b in range(batch): for i in range(N): if valid_mask[b, i]: px, py = bev_x[b, i], bev_y[b, i] bev_grid[b, :, py, px] = point_features[b, i] bev_features = self.bev_conv(bev_grid) return bev_features
class RadarCameraBEVFusion(nn.Module): """ 雷达-摄像头BEV融合网络 """ def __init__( self, bev_size: Tuple[int, int] = (200, 200), feature_dim: int = 64 ): super().__init__() self.camera_encoder = BEVFeatureExtractor( bev_size=bev_size, feature_dim=feature_dim ) self.radar_encoder = RadarBEVEncoder( bev_size=bev_size, feature_dim=feature_dim ) self.fusion = nn.Sequential( nn.Conv2d(feature_dim * 2, feature_dim, kernel_size=3, padding=1), nn.BatchNorm2d(feature_dim), nn.ReLU(inplace=True), nn.Conv2d(feature_dim, feature_dim, kernel_size=3, padding=1), nn.BatchNorm2d(feature_dim), nn.ReLU(inplace=True) ) self.detection_head = nn.Sequential( nn.Conv2d(feature_dim, 32, kernel_size=3, padding=1), nn.ReLU(inplace=True), nn.Conv2d(32, 6, kernel_size=1) ) def forward( self, images: torch.Tensor, radar_points: torch.Tensor ) -> Tuple[torch.Tensor, dict]: """ Args: images: (batch, 3, H, W) radar_points: (batch, N, 5) Returns: detections: (batch, 6, bev_H, bev_W) features: 中间特征 """ camera_bev, depth_pred = self.camera_encoder(images) radar_bev = self.radar_encoder(radar_points) fused = torch.cat([camera_bev, radar_bev], dim=1) fused = self.fusion(fused) detections = self.detection_head(fused) return detections, { 'camera_bev': camera_bev, 'radar_bev': radar_bev, 'fused': fused, 'depth_pred': depth_pred }
if __name__ == "__main__": batch_size = 2 images = torch.randn(batch_size, 3, 1080, 1920) n_points = 100 radar_points = torch.randn(batch_size, n_points, 5) model = RadarCameraBEVFusion( bev_size=(200, 200), feature_dim=64 ) detections, features = model(images, radar_points) print("=== 雷达-摄像头BEV融合测试 ===") print(f"图像形状: {images.shape}") print(f"雷达点云形状: {radar_points.shape}") print(f"检测结果形状: {detections.shape}") print(f"参数量: {sum(p.numel() for p in model.parameters()):,}")
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