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arXiv 0802.0400astro-ph
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CMB映射信号分离的改进ICA方法

A Modified ICA Approach for Signal Separation in CMB Maps

Robertio Vio, Paola Andreani

摘要:

目标:在宇宙学中,前景污染与宇宙微波背景(CMB)的分离是数字信号处理中最具挑战性和重要的问题之一。这个问题变得更加困难的情况下,如CMB偏振观测,其中可用的“先验”信息的量是有限的。在这种情况下,有必要采取“盲分离”的方法。独立成分分析(ICA)是这类方法中的一个重要成员。在其原始公式中,该方法具有各种有趣的特征,但也有一些限制。最严重的问题之一是很难考虑到任何预先掌握的信息。特别是,ICA不能利用CMB的发射在所有观测频率下都是相同的这一事实。在这里,我们展示如何处理这个问题。所提出的方法与“内部线性组成”(ILC)技术的连接也说明了。方法:经典的ICA方法的修改,并分析其特性分析和数值实验。结果:改进后的ICA结果更稳定,质量更好。

英文摘要:

AIMS: One of the most challenging and important problem of digital signal processing in Cosmology is the separation of foreground contamination from cosmic microwave background (CMB). This problem becomes even more difficult in situations, as the CMB polarization observations, where the amount of available "a priori" information is limited. In this case, it is necessary to resort to the "blind separation" methods. One important member of this class is represented by the "Independent Components Analysis" (ICA). In its original formulation, this method has various interesting characteristics, but also some limits. One of the most serious is the difficulty to take into account any information available in advance. In particular, ICA is not able to exploit the fact that emission of CMB is the same at all the frequencies of observations. Here, we show how to deal with this question. The connection of the proposed methodology with the "Internal Linear Composition" (ILC) technique is also illustrated. METHODS: A modification of the classic ICA approach is presented and its characteristics are analyzed both analytically and by means of numerical experiments. RESULTS: The modified version of ICA appears to provide more stable results and of better quality.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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