Based on the diffraction theory model for hot-image formation, the evolution of hot-images induced by multiscatterers located in the same plane perpendicular to the propagation axis is numerically simulated. The simul...Based on the diffraction theory model for hot-image formation, the evolution of hot-images induced by multiscatterers located in the same plane perpendicular to the propagation axis is numerically simulated. The simulation results show that hot-images induced by coplanar multi-scatterers are also coplanar no matter whether they exist simultaneously or severally. However, if they exist simultaneously the peak intensity of the primary hot-images is weaker than if they exist severally. The unequal competition for energy between the scattered beams from the scatterers leads to the fact that part of the corresponding hot-images are relatively enhanced and the others are restrained. The results show that the hot-images of certain scatterers become stronger when any of these parameters, i.e. amplitude modulation coefficient, phase modulation coefficient and size of the surrounding scatterer, decrease.展开更多
针对现有的目标检测算法检测表面亮度低的小尺度星系时效果不理想的问题,该文提出了一种基于掩码机制与目标交叉认证的低表面亮度的小尺度星系检测方法。首先,针对天文图像设计了一个基于目标总数变化率的阈值确定方法来获取阈值;其次,...针对现有的目标检测算法检测表面亮度低的小尺度星系时效果不理想的问题,该文提出了一种基于掩码机制与目标交叉认证的低表面亮度的小尺度星系检测方法。首先,针对天文图像设计了一个基于目标总数变化率的阈值确定方法来获取阈值;其次,设计了基于掩码机制的目标去除方法和基于自适应半径的点源区域获取方法,结合图像分割和点源检测算法生成非检测目标掩码,与原图进行逐点相乘去除图中体积较大、亮度较高的非检测目标,得到亮度微弱、体积较小的候选者;然后,利用图像分割技术获取候选体分割区域,计算区域面积和质心坐标定位候选者;最后,通过目标交叉认证的方法将候选者与星表中真实记录的星体进行坐标差值计算获取星系目标。实验与分析表明,在SDSS(Sloan Digital Sky Survey)天文数据集上该方法对低表面亮度的小尺度目标检测率可达约94.90%,星系的识别率可达到约89.21%,都高于经典的目标检测算法。展开更多
基金supported by the Joint Foundation of National Natural Science Foundation of China and the Science Foundation of the Chinese Academy of Engineering Physics,China(Grant No 10576023)the Doctorate Foundation of Northwestern Polytechnical University,China(Grant No CX200714)
文摘Based on the diffraction theory model for hot-image formation, the evolution of hot-images induced by multiscatterers located in the same plane perpendicular to the propagation axis is numerically simulated. The simulation results show that hot-images induced by coplanar multi-scatterers are also coplanar no matter whether they exist simultaneously or severally. However, if they exist simultaneously the peak intensity of the primary hot-images is weaker than if they exist severally. The unequal competition for energy between the scattered beams from the scatterers leads to the fact that part of the corresponding hot-images are relatively enhanced and the others are restrained. The results show that the hot-images of certain scatterers become stronger when any of these parameters, i.e. amplitude modulation coefficient, phase modulation coefficient and size of the surrounding scatterer, decrease.
文摘针对现有的目标检测算法检测表面亮度低的小尺度星系时效果不理想的问题,该文提出了一种基于掩码机制与目标交叉认证的低表面亮度的小尺度星系检测方法。首先,针对天文图像设计了一个基于目标总数变化率的阈值确定方法来获取阈值;其次,设计了基于掩码机制的目标去除方法和基于自适应半径的点源区域获取方法,结合图像分割和点源检测算法生成非检测目标掩码,与原图进行逐点相乘去除图中体积较大、亮度较高的非检测目标,得到亮度微弱、体积较小的候选者;然后,利用图像分割技术获取候选体分割区域,计算区域面积和质心坐标定位候选者;最后,通过目标交叉认证的方法将候选者与星表中真实记录的星体进行坐标差值计算获取星系目标。实验与分析表明,在SDSS(Sloan Digital Sky Survey)天文数据集上该方法对低表面亮度的小尺度目标检测率可达约94.90%,星系的识别率可达到约89.21%,都高于经典的目标检测算法。
