迭代投影相位恢复算法的统一评价

A new non-iterative self-referencing interferometer in optical phase imaging and holographic microscopy, HOLOCAM

Phase retrieval and imaging phase measurements are fields of intense research. It has recently been shown that phase retrieval from self-referencing interferograms (SRI) can be reformulated leading to a stable, linear equation provided the amplitude of the field is known from prior measurement steps (HOLOCAM). Consequently, the numerical solution thereof is straightforward. This is a big achievement since convergence is otherwise not always guaranteed. Applications are expected in X-ray microscopy, general phase retrieval, holography, tomography and optical imaging.

基于投影算法的实时迭代叠层成像

Live Iterative Ptychography with projection-based algorithms

本文提出将投影类叠层衍射相位恢复算法改造为实时迭代形式，借鉴音频处理中的RTISI算法族，实现扫描过程中的即时重建、任意尺寸物体重建和自适应扫描，并在相近计算负载下取得更高质量的重建结果。

Three-dimensional double helical DNA structure directly revealed from its X-ray fiber diffraction pattern by iterative phase retrieval

Coherent diffraction imaging (CDI) allows the retrieval of the structure of an isolated object, such as a macromolecule, from its diffraction pattern. CDI requires the fulfilment of two conditions: the imaging radiation must be coherent and the object must be isolated. We discuss that it is possible to directly retrieve the molecular structure from its diffraction pattern which was acquired neither with coherent radiation nor from an individual molecule, provided the molecule exhibits periodicity in one direction, as in the case of fiber diffraction. We demonstrate that by applying iterative p…

通过交替投影与空初始化使用一个或两个衍射图案进行相位恢复

Phase Retrieval with One or Two Diffraction Patterns by Alternating Projection with Null Initialization

本文提出多种交替投影方法解决最多两个编码衍射图案的相位恢复问题，通过空初始化提高收敛速度和准确性，证明了其在非凸优化中的全局收敛性。

三维层析相位恢复与解缠

3D Tomographic Phase Retrieval and Unwrapping

本文建立三维相位恢复的唯一性理论，提出编码/非编码测量方案、三维相位解缠条件和投影层析唯一性证明，将三维相位恢复约化为相位投影层析问题。

Real-time phase-retrieval and wavefront sensing enabled by an artificial neural network

In this manuscript we demonstrate a method to reconstruct the wavefront of focused beams from a measured diffraction pattern behind a diffracting mask in real-time. The phase problem is solved by means of a neural network, which is trained with simulated data and verified with experimental data. The neural network allows live reconstructions within a few milliseconds, which previously with iterative phase retrieval took several seconds, thus allowing the adjustment of complex systems and correction by adaptive optics in real time. The neural network additionally outperforms iterative phase ret…

Iterative phase retrieval for digital holography

This paper provides a tutorial of iterative phase retrieval algorithms based on the Gerchberg-Saxton (GS) algorithm applied in digital holography. In addition, a novel GS-based algorithm that allows reconstruction of 3D samples is demonstrated. The GS-based algorithms recover complex-valued wavefront by wavefront back-and forth propagation between two planes with constraints superimposed in these two planes. Iterative phase retrieval allows quantitatively correct and twin-image-free reconstructions of object amplitude and phase distributions from its in-line hologram. The present work derives …

Reconstruction of missing information in diffraction patterns and holograms by iterative phase retrieval

It is demonstrated that an object distribution can be successfully retrieved from its diffraction pattern or hologram, even if some of the measured intensity samples are missing. The maximum allowable number of missing values depends on the linear oversampling ratio s, where the higher the value of s, the more intensity samples can be missing. For a real-valued object, the ratio of missing pixels to the total number of pixels should not exceed (1 - 2/s^2) or (1 - 1/s^2) in the acquired diffraction pattern or hologram, respectively. For example, even 5% of the measured intensity values at an ov…