为快速、准确地检测船舶目标,提出一种基于YOLOv3算法的船舶双目视觉检测与定位方法。在特征学习时针对样本中不同船舶长宽比例,重新聚类样本中心锚点框,增强对船舶检测的准确性;利用SURF算法进行特征匹配,并引入双目测距算法,实现目标...为快速、准确地检测船舶目标,提出一种基于YOLOv3算法的船舶双目视觉检测与定位方法。在特征学习时针对样本中不同船舶长宽比例,重新聚类样本中心锚点框,增强对船舶检测的准确性;利用SURF算法进行特征匹配,并引入双目测距算法,实现目标的测距与定位。实验结果表明,该方法在每秒传输图片30帧的情况下,平均检测精度达到94%,在1 n mile内的目标平均定位误差为11 m左右,与现有检测算法相比,具有更好的实时性、准确性。该方法对智能船舶视觉感知信息与雷达、AIS信息的融合,以及避碰辅助决策具有非常重要的作用。展开更多
A reconfigurable, self-phase quadrifilar helical antenna was designed at BDS/GPS frequency band. The impedance, gain and directivity of the antenna were studied by HFSS based on FEM （finite element method） and exper...A reconfigurable, self-phase quadrifilar helical antenna was designed at BDS/GPS frequency band. The impedance, gain and directivity of the antenna were studied by HFSS based on FEM （finite element method） and experiment. Results show the beam width of the main lobe of the pattern can reach over 160° with the help of the load on the top of the antenna. And the power of the side-lobe level is very low. In addition, the quadrifitar helix antenna has excellent right-hand circular polarization performance with a beam width of 180°. Both single-frequency and double-frequency communications can be carried out by the antenna in the ranges between 1.2 and 1.8 GHz, with the bandwidth of each frequency about 60 MHz, the simulating and experimental results are nearly the same.展开更多
文摘为快速、准确地检测船舶目标,提出一种基于YOLOv3算法的船舶双目视觉检测与定位方法。在特征学习时针对样本中不同船舶长宽比例,重新聚类样本中心锚点框,增强对船舶检测的准确性;利用SURF算法进行特征匹配,并引入双目测距算法,实现目标的测距与定位。实验结果表明,该方法在每秒传输图片30帧的情况下,平均检测精度达到94%,在1 n mile内的目标平均定位误差为11 m左右,与现有检测算法相比,具有更好的实时性、准确性。该方法对智能船舶视觉感知信息与雷达、AIS信息的融合,以及避碰辅助决策具有非常重要的作用。
基金The research is supported by Shanghai Shuguang Plan Project （No： 15SG44） and NSFC of China （No： 51579143, 51379121 and 61304230） and China Postdoctoral Science Foundation （No： 2015M581585）.
文摘A reconfigurable, self-phase quadrifilar helical antenna was designed at BDS/GPS frequency band. The impedance, gain and directivity of the antenna were studied by HFSS based on FEM （finite element method） and experiment. Results show the beam width of the main lobe of the pattern can reach over 160° with the help of the load on the top of the antenna. And the power of the side-lobe level is very low. In addition, the quadrifitar helix antenna has excellent right-hand circular polarization performance with a beam width of 180°. Both single-frequency and double-frequency communications can be carried out by the antenna in the ranges between 1.2 and 1.8 GHz, with the bandwidth of each frequency about 60 MHz, the simulating and experimental results are nearly the same.
