天文斑点成像技术中的噪声影响分析

Analysis of Noise Influence on Astronomical Speckle Imaging Techniques

为进一步说明天文像复原新方法———迭代位移叠加法的性质 ,对探测器的附加噪声在斑点干涉术、斑点掩模法和迭代位移叠加法中的影响分别进行了分析。结果表明 :在斑点掩模法中 ,复杂的噪声高阶矩统计被引入了重谱的噪声偏差 ,因此对噪声极为敏感 ,使数据处理更加复杂化 ;与斑点掩模法相比 ,迭代位移叠加法仅涉及对噪声的一阶矩统计平均 ,所以此新方法的特点是对噪声不敏感 。

In order to further illustrate the character of the new method of iterative shift and add for astronomical image reconstruction, the inflence of additive detector noise on the speckle interferometry, the speckle masking and the iterative shift and add is analysed respectively. The results showed that the complex higher order moment statistics of the noise is brought in to the noise bias of the bispectrum, for this reason the speckle masking is very sensitive to the noise and the data processing is more comlpicated. In comparison with the speckle masking, the iterative shift and add only involves the first order moment statistic average of the noise, therefore the character of the new method is insensitive to the noise, and so it has an advantage that the image reconstruction processing is very simple and direct.