Super-resolution imaging with radio interferometry using sparse modeling
Super-resolution imaging with radio interferometry using sparse modeling
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DOI：
10.1093/pasj/psu070
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发表时间：
2014-10-01
影响因子：
2.3
通讯作者：
Ikeda, Shiro
中科院分区：
文献类型：
--
作者：
Honma, Mareki;Akiyama, Kazunori;Ikeda, Shiro
提出了一种新的基于稀疏建模的无线电干涉超分辨率图像获取技术。在标准的无线电干涉测量中，(u，v)的采样经常是不完整的，因此从观测能见度获得图像成为一个确定不足的问题，而所谓的“补零”技术经常被用来填充(u，v)平面中未采样的网格，导致有限的光束尺寸和大量的旁瓣导致图像退化。在本文中，我们证明了基于稀疏建模的直接求解这样的欠定问题(在本文中，最小绝对收缩和选择算子，称为套索)避免了由零填充引入的上述问题，从而导致可以再现比标准光束尺寸(衍射极限)更精细的超分辨率图像。我们给出了干涉成像的一维和二维模拟结果，并讨论了它对超分辨率成像的意义，特别是用毫米甚长基线干涉成像(VLBI)对黑洞阴影的成像。
We propose a new technique to obtain super-resolution images with radio interferometry using sparse modeling. In standard radio interferometry, sampling of (u, v) is quite often incomplete and thus obtaining an image from observed visibilities becomes an underdetermined problem, and a technique of so-called "zero-padding" is often used to fill up unsampled grids in the (u, v) plane, resulting in image degradation by finite beam size as well as numerous side-lobes. In this paper we show that directly solving such an underdetermined problem based on sparse modeling (in this paper, Least Absolute Shrinkage and Selection Operator, known as LASSO) avoids the above problems introduced by zero-padding, leading to super-resolution images in which structure finer than the standard beam size (diffraction limit) can be reproduced. We present results of one-dimensional and two-dimensional simulations of interferometric imaging, and discuss its implications for super-resolution imaging, particularly focusing on imaging of black hole shadows with millimeter VLBI (Very Long Baseline Interferometry).