基于鸟瞰图的空间-通道注意力多传感器融合

基于鸟瞰图(Bird′s-Eye View,BEV)的目标感知算法现正成为研究热点,但少有针对BEV的多传感器融合.因此,文中提出基于空间-通道注意力的多传感器融合模块,对不同模态的特征数据增加局部注意力机制,能有效修正多传感器之间的空间误差.利用转置注意力操作,充分融合图像和点云数据,消解不同模态语义信息之间的异质性,使融合的BEV特征在不引入空间偏差的同时,有效结合多传感器各自的独特信息,实现更全面准确的感知.在nuScenes数据集上的实验以及大量的消融实验表明,文中融合模块能有效提升目标检测算法的精度,可视化结果展现融合后的特征具有更完整、准确的特征信息,可明显提升对远处物体的检测.

Recognition of field roads based on improved U-Net++Network

Unmanned driving of agricultural machinery has garnered significant attention in recent years,especially with the development of precision farming and sensor technologies.To achieve high performance and low cost,perception tasks are of great importance.In this study,a low-cost and high-safety method was proposed for field road recognition in unmanned agricultural machinery.The approach of this study utilized point clouds,with low-resolution Lidar point clouds as inputs,generating high-resolution point clouds and Bird's Eye View(BEV)images that were encoded with several basic statistics.Using a BEV representation,road detection was reduced to a single-scale problem that could be addressed with an improved U-Net++neural network.Three enhancements were proposed for U-Net++:1)replacing the convolutional kernel in the original U-Net++ with an Asymmetric Convolution Block(ACBlock);2)adding a multi-branch Asymmetric Dilated Convolutional Block(MADC)in the highest semantic information layer;3)adding an Attention Gate(AG)model to the long-skip-connection in the decoding stage.The results of experiments of this study showed that our algorithm achieved a Mean Intersection Over Union of 96.54% on the 16-channel point clouds,which was 7.35 percentage points higher than U-Net++.Furthermore,the average processing time of the model was about 70 ms,meeting the time requirements of unmanned driving in agricultural machinery.The proposed method of this study can be applied to enhance the perception ability of unmanned agricultural machinery thereby increasing the safety of field road driving.

基于鸟瞰图融合的多级旋转等变目标检测网络

随着自动驾驶系统的发展,针对道路场景下的3D目标检测受到研究人员的广泛关注。然而,大多数基于单一传感器或者多传感器融合的目标检测方法未考虑实际道路场景中车辆旋转,使得捕获的场景同步旋转,从而导致目标检测性能降低。针对这类问题,提出一种基于多传感器融合的多级全局旋转等变目标检测网络架构,以缓解场景旋转造成的目标检测困难,从而提高目标检测性能。首先,对体素内部进行各点之间距离编码,增强局部点云几何信息,并提取体素的全局旋转等变特征;其次,引入图像的语义信息并提取全局旋转等变特征,进一步提高网络性能;最后,将具有旋转等变性的点云和图像信息在鸟瞰图上进行融合,并嵌入群等变网络提取融合鸟瞰图级全局旋转等变特征。实验结果表明,该网络架构在nuScenes验证集上达到了68.7%的平均精度均值(mAP)和71.7的nuScenes检测分数(NDS),以及平均角度误差均值(mAOE)降低到0.288,相比主流的目标检测方法,其实现了网络架构本身的旋转等变性并在性能上得到了提升,此外,各个组件对于整体网络架构的目标检测性能提升都起到了重要作用。