基于能量累加的空间目标星像质心定位

Centroid location for space targets based on energy accumulation

研究了CCD观测图像的亚像素级高精度质心定位方法以提高目标星像的天文定位精度。分析了影响定位精度的主要因素,如图像噪声、离散化采样误差及定位窗口选择等,结合CCD弥散斑的成像特性,提出了一种基于能量累加的空间目标星像质心定位方法。该方法使用插值方式降低离散采样点和实际感光区域光线照度的不一致性;利用弥散斑能量累加自适应地确定目标星像的有效窗口,优化目标星像灰度,消除随机噪声的影响;并采用平方加权质心定位方法进行质心计算。实验结果表明,该方法具有较强的抗干扰能力和稳定性,定位精度可达0.01pixel,适用于低信噪比条件下的质心定位计算。

Sub-pixel positioning technology for CCD images is proposed to improve the astronomical location precision of space targets. The main factors affecting the positioning accuracy of targe centroids,such as image noise,discrete sampling error and window size selection are analyzed.Combining with the CCD imaging characteristics for dispersion spots,a location method for target centroids based on energy accumulation is proposed.This method uses the interpolation technique to reduce the illumination inconsistency between actual sensitive area and discrete sample points,and uses the energy accumulation of dispersion spot to select the efficient target window for optimizing target gray and eliminating random noises.Finally,a squared weighted centroid localization method is taken to calculate the centroid position.Experimental results show that the method has strong anti-interference ability and stability.It can offer a positioning accuracy of 0.01 pixel and is suitable for a low SNR condition.