Multi-frequency image reconstruction for radio interferometry. A regularized inverse problem approach
Multi-frequency image reconstruction for radio interferometry. A regularized inverse problem approach
复制标题
用于无线电干涉测量的多频图像重建。
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
O. Smirnov
中科院分区：
文献类型：
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作者：
A. Ferrari;J. Deguignet;C. Ferrari;D. Mary;A. Schutz;O. Smirnov
本文描述了一种用于射电干涉测量中宽带成像的“空谱”反卷积算法。与现有的多频重建算法相比，该方法不依赖于天空亮度谱分布模型。这种非参数方法对于新一代的低频射电望远镜特别有意义。所提出的解决方案将重建问题形式化为具有空间和谱正则化的凸优化问题。这种方法的效率已经被证明为窄带图像重建和目前的贡献可以被认为是其扩展到多频的情况下。由于频带的数量乘以反问题的大小，特别注意的是致力于迭代大规模优化算法的推导。结果表明，该方法的主要计算瓶颈，这是在一个线性系统的分辨率，可以有效地克服一个完全并行的实施w.r.t.频率，其中每个处理器重建窄带图像。所有其他优化步骤都非常快。该算法在Julia中的并行实现可在此https URL上公开获得。初步模拟说明了该方法的性能及其重建复杂空间光谱结构的能力。
We describe a "spatio-spectral" deconvolution algorithm for wide-band imaging in radio interferometry. In contrast with the existing multi-frequency reconstruction algorithms, the proposed method does not rely on a model of the sky-brightness spectral distribution. This non-parametric approach can be of particular interest for the new generation of low frequency radiotelescopes. The proposed solution formalizes the reconstruction problem as a convex optimization problem with spatial and spectral regularizations. The efficiency of this approach has been already proven for narrow-band image reconstruction and the present contribution can be considered as its extension to the multi-frequency case. Because the number of frequency bands multiplies the size of the inverse problem, particular attention is devoted to the derivation of an iterative large scale optimization algorithm. It is shown that the main computational bottleneck of the approach, which lies in the resolution of a linear system, can be efficiently overcome by a fully parallel implementation w.r.t. the frequencies, where each processor reconstructs a narrow-band image. All the other optimization steps are extremely fast. A parallel implementation of the algorithm in Julia is publicly available at this https URL Preliminary simulations illustrate the performances of the method and its ability to reconstruct complex spatio-spectral structures.