A novel method of reconstruction for weak-phase optical interferometry
A novel method of reconstruction for weak-phase optical interferometry
复制标题
一种新的弱相位光学干涉重建方法
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
G. Le Besnerais
中科院分区：
文献类型：
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作者：
S. Meimon;L. Mugnier;G. Le Besnerais
目前的光学干涉仪受到每个望远镜上未知湍流相位的影响。因此，该仪器测量的复数傅里叶样本乘以与每对望远镜之间的湍流差分活塞相对应的未知相位器。因此，唯一不受影响的相位信息是每个相干子阵列的闭合相位。遵循无线电干涉测量范式，我们通过引入系统像差参数来解释相位信息的缺乏，这些系统像差参数在结构上类似于湍流差动活塞。然后，我们通过最小化对象中的原始标准和这些像差来重建对象。我们最近设计了一个度量，使得最小化问题对于给定的象差是凸的，同时准确地建模噪声统计。该联合判据是通过考虑该度规中的像差来获得的。在这里，我们展示了如何计算像差步长的联合准则的全局最小值，尽管后者明显不是单峰的。这是通过利用已知对象的象差估计问题的可分离结构来实现的。然后，我们通过交替地针对当前像差和当前对象的像差来优化对象来最小化。我们目前正在用实验数据测试我们的技术。
Current optical interferometers are affected by unknown turbulent phases on each telescope. The complex Fourier samples measured by the instrument are thus multiplied by unknown phasers corresponding to the turbulent differential pistons between each couple of telescopes. So, the only unaffected phase information is the closure phase of each coherent sub-array. Following the radio-interferometry paradigm, we account for the lack of phase information by introducing system aberration parameters, which are structurally analogous to the turbulent differential pistons. Then, we reconstruct the object by minimizing an original criterion in the object and these aberrations. We have recently designed a metric such that the minimization problem is convex for given aberrations while modeling accurately the noise statistics. The joint criterion is obtained by taking into account the aberrations in this metric. Here, we show how to compute the global minimum of the joint criterion for the aberration step, in spite of the fact that the latter is dramatically non unimodal. This is achieved by exploiting the separable structure of the aberration estimation problem for a known object. Then, we minimize the by optimizing alternatively the object for the current aberrations and the aberrations for the current object. We are currently testing our technique on experimental data.