空间目标光子数密度对斑点成像的影响

The Influence of the Space Object Photon Density on Speckle Imaging

空间扩展目标斑点成像的质量受到短曝光像中光子密度的限制.通过有限光子数短曝光像的模拟,对短曝光像频谱信噪比进行了计算,研究了有限光子数下大气光学系统传递函数的估计方法,光子数有限时目标振幅谱和相位谱中的有偏项影响,点源目标恢复图像的信噪比和动态范围.实验结果表明,根据斑点成像系统的参数,可以定量地确定光子密度、短曝光像数目和恢复图像的质量(分辨率)之间的关系.

The speckle imaging quality of space extended objects is limited by photon density in short exposure images. The generation of simulated short exposure images under limited photon density, signal to noise ratio calculation of short exposure image spectrums, estimation of system transfer function, the influence of bias term in amplitude and phase spectrums with limited photon density, signal to noise ration and dynamic range of reconstructed point source image, and the speckle imaging process for reconstructing images of extended object are presented in this paper. The experiment＇ s results show that from the known system parameters, the procedures introduced here can be used to quantitatively detennine the relationship between the photon density, the frame number of short exposure images and the quality（resolution） of restored images.