Oversampling smoothness: an effective algorithm for phase retrieval of noisy diffraction intensities
Oversampling smoothness: an effective algorithm for phase retrieval of noisy diffraction intensities
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DOI：
10.1107/s0021889813002471
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发表时间：
2013-04-01
影响因子：
6.1
通讯作者：
Miao, Jianwei
中科院分区：
文献类型：
--
作者：
Rodriguez, Jose A.;Xu, Rui;Miao, Jianwei
相干衍射成像（CDI）是一种高分辨率无透镜显微镜技术，已被应用于使用同步辐射、X射线自由电子激光、高次谐波产生、软X射线激光和电子对各种样品进行成像。尽管最近的快速进展，它仍然是一个挑战，重建精细的功能，在弱散射的对象，如生物标本从嘈杂的数据。本文提出了一种有效的过采样平滑迭代算法，用于噪声衍射强度的相位恢复。OSS利用真实的空间中的支撑之外的区域中的像素或体素之间的相关性信息。通过在迭代过程的不同阶段（即平滑度约束）将空间频率滤波器适当地应用于支持之外的像素或体素，OSS在混合输入输出（HIO）和误差减少（ER）算法之间找到平衡，以搜索解空间中的全局最小值，同时减少重建中的振荡。泊松噪声的数值模拟和来自生物细胞的实验数据表明，OSS在所有噪声水平下在重建的准确性和一致性方面始终优于HIO，ER-HIO和噪声鲁棒（NR）-HIO算法。预计OSS将在快速增长的CDI领域以及需要从噪声傅立叶幅度进行相位恢复的其他学科中找到应用。MATLAB（The MathWorks Inc.，Natick，MA，USA）的OSS算法的源代码可从http://www.physics.ucla.edu/research/imaging免费获得。
Coherent diffraction imaging (CDI) is high-resolution lensless microscopy that has been applied to image a wide range of specimens using synchrotron radiation, X-ray free-electron lasers, high harmonic generation, soft X-ray lasers and electrons. Despite recent rapid advances, it remains a challenge to reconstruct fine features in weakly scattering objects such as biological specimens from noisy data. Here an effective iterative algorithm, termed oversampling smoothness (OSS), for phase retrieval of noisy diffraction intensities is presented. OSS exploits the correlation information among the pixels or voxels in the region outside of a support in real space. By properly applying spatial frequency filters to the pixels or voxels outside the support at different stages of the iterative process (i.e. a smoothness constraint), OSS finds a balance between the hybrid input-output (HIO) and error reduction (ER) algorithms to search for a global minimum in solution space, while reducing the oscillations in the reconstruction. Both numerical simulations with Poisson noise and experimental data from a biological cell indicate that OSS consistently outperforms the HIO, ER-HIO and noise robust (NR)-HIO algorithms at all noise levels in terms of accuracy and consistency of the reconstructions. It is expected that OSS will find application in the rapidly growing CDI field, as well as other disciplines where phase retrieval from noisy Fourier magnitudes is needed. The MATLAB (The MathWorks Inc., Natick, MA, USA) source code of the OSS algorithm is freely available from http://www.physics.ucla.edu/research/imaging.