In the signal processing for metrewave radar, the reflection paths of target echoes can cause severe error in the elevation estimation for the low-angle target tracking. The exact angles of the reflection paths are un...In the signal processing for metrewave radar, the reflection paths of target echoes can cause severe error in the elevation estimation for the low-angle target tracking. The exact angles of the reflection paths are unknown beforehand, and therefore, the reflection paths can not be suppressed easily. Therefore, in this article, an improved reflection paths suppression approach is presented. A block matrix aggregate is constructed based on the possible angles of the reflection paths. Combined with the beamforming-like processing, a generalized maximum likelihood estimation is derived to optimize the estimation. Moreover, the noise reduction method based on the Toeplitz covariance matrix is used for better performance. This approach is applied to the real data collected by the low-angle tracking radar with 8-channel vertical array. The experiment results show that the reflection effects are reduced and the accuracy of the elevation estimate is improved.展开更多
针对目前电动车头盔小目标检测的精度低、鲁棒性差,相关系统不完善等问题,提出了基于改进YOLOv5s的电动车头盔检测算法。所提算法引入卷积块注意力模块(CBAM)和协调注意力(CA)模块,采用改进的非极大值抑制(NMS),即DIoU-NMS(Distance Int...针对目前电动车头盔小目标检测的精度低、鲁棒性差,相关系统不完善等问题,提出了基于改进YOLOv5s的电动车头盔检测算法。所提算法引入卷积块注意力模块(CBAM)和协调注意力(CA)模块,采用改进的非极大值抑制(NMS),即DIoU-NMS(Distance Intersection over Union-Non Maximum Suppression);同时增加多尺度特征融合检测,并结合密集连接网络改善特征提取效果;最后,建立了电动车驾驶人头盔检测系统。在自建的电动车头盔佩戴数据集上,当交并比(IoU)为0.5时,所提算法的平均精度均值(mAP)比原始YOLOv5s提升了7.1个百分点,召回率(Recall)提升了1.6个百分点。实验结果表明,所提改进的YOLOv5s算法更能满足在实际情况中对电动车及驾驶员头盔的检测精度要求,一定程度上降低了电动车交通事故的发生率。展开更多
文摘In the signal processing for metrewave radar, the reflection paths of target echoes can cause severe error in the elevation estimation for the low-angle target tracking. The exact angles of the reflection paths are unknown beforehand, and therefore, the reflection paths can not be suppressed easily. Therefore, in this article, an improved reflection paths suppression approach is presented. A block matrix aggregate is constructed based on the possible angles of the reflection paths. Combined with the beamforming-like processing, a generalized maximum likelihood estimation is derived to optimize the estimation. Moreover, the noise reduction method based on the Toeplitz covariance matrix is used for better performance. This approach is applied to the real data collected by the low-angle tracking radar with 8-channel vertical array. The experiment results show that the reflection effects are reduced and the accuracy of the elevation estimate is improved.
文摘针对目前电动车头盔小目标检测的精度低、鲁棒性差,相关系统不完善等问题,提出了基于改进YOLOv5s的电动车头盔检测算法。所提算法引入卷积块注意力模块(CBAM)和协调注意力(CA)模块,采用改进的非极大值抑制(NMS),即DIoU-NMS(Distance Intersection over Union-Non Maximum Suppression);同时增加多尺度特征融合检测,并结合密集连接网络改善特征提取效果;最后,建立了电动车驾驶人头盔检测系统。在自建的电动车头盔佩戴数据集上,当交并比(IoU)为0.5时,所提算法的平均精度均值(mAP)比原始YOLOv5s提升了7.1个百分点,召回率(Recall)提升了1.6个百分点。实验结果表明,所提改进的YOLOv5s算法更能满足在实际情况中对电动车及驾驶员头盔的检测精度要求,一定程度上降低了电动车交通事故的发生率。