While moving ahead with the object detection technology, especially deep neural networks, many related tasks, such as medical application and industrial automation, have achieved great success. However, the detection ...While moving ahead with the object detection technology, especially deep neural networks, many related tasks, such as medical application and industrial automation, have achieved great success. However, the detection of objects with multiple aspect ratios and scales is still a key problem. This paper proposes a top-down and bottom-up feature pyramid network(TDBU-FPN),which combines multi-scale feature representation and anchor generation at multiple aspect ratios. First, in order to build the multi-scale feature map, this paper puts a number of fully convolutional layers after the backbone. Second, to link neighboring feature maps, top-down and bottom-up flows are adopted to introduce context information via top-down flow and supplement suboriginal information via bottom-up flow. The top-down flow refers to the deconvolution procedure, and the bottom-up flow refers to the pooling procedure. Third, the problem of adapting different object aspect ratios is tackled via many anchor shapes with different aspect ratios on each multi-scale feature map. The proposed method is evaluated on the pattern analysis, statistical modeling and computational learning visual object classes(PASCAL VOC)dataset and reaches an accuracy of 79%, which exhibits a 1.8% improvement with a detection speed of 23 fps.展开更多
In modern war,radar countermeasure is becoming increasingly fierce,and the enemy jamming time and pattern are changing more randomly.It is challenging for the radar to efficiently identify jamming and obtain precise p...In modern war,radar countermeasure is becoming increasingly fierce,and the enemy jamming time and pattern are changing more randomly.It is challenging for the radar to efficiently identify jamming and obtain precise parameter information,particularly in low signal-to-noise ratio(SNR)situations.In this paper,an approach to intelligent recognition and complex jamming parameter estimate based on joint time-frequency distribution features is proposed to address this challenging issue.Firstly,a joint algorithm based on YOLOv5 convolutional neural networks(CNNs)is proposed,which is used to achieve the jamming signal classification and preliminary parameter estimation.Furthermore,an accurate jamming key parameters estimation algorithm is constructed by comprehensively utilizing chi-square statistical test,feature region search,position regression,spectrum interpolation,etc.,which realizes the accurate estimation of jamming carrier frequency,relative delay,Doppler frequency shift,and other parameters.Finally,the approach has improved performance for complex jamming recognition and parameter estimation under low SNR,and the recognition rate can reach 98%under−15 dB SNR,according to simulation and real data verification results.展开更多
交通标志检测是自动驾驶系统、辅助驾驶系统(DAS)的重要组成部分,对行车安全具有重要意义。针对小目标交通标志检测时受光照、恶劣天气等因素影响而导致的检测精度低、漏检率高等问题,提出一种基于改进YOLOv5的小目标交通标志检测算法...交通标志检测是自动驾驶系统、辅助驾驶系统(DAS)的重要组成部分,对行车安全具有重要意义。针对小目标交通标志检测时受光照、恶劣天气等因素影响而导致的检测精度低、漏检率高等问题,提出一种基于改进YOLOv5的小目标交通标志检测算法。首先,引入空间到深度卷积(SPD-Conv)对特征图进行下采样,有效避免小目标信息丢失,提高小目标敏感度。其次,基于加权双向特征金字塔网络(BiFPN)改进颈部网络,添加跨层连接以融合多尺度特征。之后,增加小目标检测层,增强小目标检测能力。最后,采用SIoU(Shape-aware Intersection over Union)损失函数,关注真实框与预测框的角度信息。实验结果表明,改进后的算法在中国交通标志检测数据集(CCTSDB2021)上的平均精度均值(mAP)达到83.5%,相较于原YOLOv5提升了7.2个百分点,检测速度满足实时性要求。展开更多
基金supported by the Program of Introducing Talents of Discipline to Universities(111 Plan)of China(B14010)the National Natural Science Foundation of China(31727901)
文摘While moving ahead with the object detection technology, especially deep neural networks, many related tasks, such as medical application and industrial automation, have achieved great success. However, the detection of objects with multiple aspect ratios and scales is still a key problem. This paper proposes a top-down and bottom-up feature pyramid network(TDBU-FPN),which combines multi-scale feature representation and anchor generation at multiple aspect ratios. First, in order to build the multi-scale feature map, this paper puts a number of fully convolutional layers after the backbone. Second, to link neighboring feature maps, top-down and bottom-up flows are adopted to introduce context information via top-down flow and supplement suboriginal information via bottom-up flow. The top-down flow refers to the deconvolution procedure, and the bottom-up flow refers to the pooling procedure. Third, the problem of adapting different object aspect ratios is tackled via many anchor shapes with different aspect ratios on each multi-scale feature map. The proposed method is evaluated on the pattern analysis, statistical modeling and computational learning visual object classes(PASCAL VOC)dataset and reaches an accuracy of 79%, which exhibits a 1.8% improvement with a detection speed of 23 fps.
基金supported by Shandong Provincial Natural Science Foundation(ZR2020MF015)Aerospace Technology Group Stability Support Project(ZY0110020009).
文摘In modern war,radar countermeasure is becoming increasingly fierce,and the enemy jamming time and pattern are changing more randomly.It is challenging for the radar to efficiently identify jamming and obtain precise parameter information,particularly in low signal-to-noise ratio(SNR)situations.In this paper,an approach to intelligent recognition and complex jamming parameter estimate based on joint time-frequency distribution features is proposed to address this challenging issue.Firstly,a joint algorithm based on YOLOv5 convolutional neural networks(CNNs)is proposed,which is used to achieve the jamming signal classification and preliminary parameter estimation.Furthermore,an accurate jamming key parameters estimation algorithm is constructed by comprehensively utilizing chi-square statistical test,feature region search,position regression,spectrum interpolation,etc.,which realizes the accurate estimation of jamming carrier frequency,relative delay,Doppler frequency shift,and other parameters.Finally,the approach has improved performance for complex jamming recognition and parameter estimation under low SNR,and the recognition rate can reach 98%under−15 dB SNR,according to simulation and real data verification results.
文摘交通标志检测是自动驾驶系统、辅助驾驶系统(DAS)的重要组成部分,对行车安全具有重要意义。针对小目标交通标志检测时受光照、恶劣天气等因素影响而导致的检测精度低、漏检率高等问题,提出一种基于改进YOLOv5的小目标交通标志检测算法。首先,引入空间到深度卷积(SPD-Conv)对特征图进行下采样,有效避免小目标信息丢失,提高小目标敏感度。其次,基于加权双向特征金字塔网络(BiFPN)改进颈部网络,添加跨层连接以融合多尺度特征。之后,增加小目标检测层,增强小目标检测能力。最后,采用SIoU(Shape-aware Intersection over Union)损失函数,关注真实框与预测框的角度信息。实验结果表明,改进后的算法在中国交通标志检测数据集(CCTSDB2021)上的平均精度均值(mAP)达到83.5%,相较于原YOLOv5提升了7.2个百分点,检测速度满足实时性要求。
