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Real time high accuracy phase contrast imaging with parallel acquisition speckle tracking

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Chinese Physics B 2021年第6期30卷 282-286页

作者：胡哲滑文强王劼 Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China SSRF Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China

X-ray speckle tracking based methods can provide results with best reported angular accuracy up to 2 nrad. However,duo to the multi-frame requirement for phase retrieval and the possible instability of the x-ray beam, mechanical and background vibration, the actual accuracy will inevitably be degraded by these time-dependent fluctuations. Therefore,not only spatial position, but also temporal features of the speckle patterns need to be considered in order to maintain the superiority of the speckle-based methods. In this paper, we propose a parallel acquisition method with advantages of real time and high accuracy, which has potential applicability to dynamic samples imaging as well as on-line beam monitoring.Through simulations, we demonstrate that the proposed method can reduce the phase error caused by the fluctuations to1% at most compared with current speckle tracking methods. Meanwhile, it can keep the accuracy deterioration within0.03 nrad, making the high theoretical accuracy a reality. Also, we find that waveforms of the incident beam have a little impact on the phase retrieved and will not influence the actual accuracy, which relaxes the requirements for speckle-based experiments.

关键词： phase contrast imaging near field speckle grating splitter

Simple phase extraction in x-ray differential phase contrast imaging

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Chinese Physics B 2016年第2期25卷 563-567页

作者：刘鑫郭金川雷耀虎李冀牛憨笨 Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Optoelectronic Engineering Shenzhen University

A fast and simple method to extract phase-contrast images from interferograms is proposed, and its effectiveness is demonstrated through simulation and experiment. For x-ray differential phase contrast imaging, a strong attenuation signal acts as an overwhelming background intensity that obscures the weak phase signal so that no obvious phase-gradient information is detectable in the raw image. By subtracting one interferogram from another, chosen at particular intervals,the phase signal can be isolated and magnified.

关键词： x-ray imaging x-ray interferometry Talbot and self-imaging effects phase contrast imaging

An Improved phase Retrieval Algorithm for X-ray In-line phase-contrast imaging

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Chinese Journal of Biomedical Engineering(English Edition) 2016年第2期25卷 69-75页

作者： GUO Yun-feng ZHUANG Tian-ge SUN Jian-qi School of Biomedical Engineering and Med-X Research Institute Shanghai Jiao Tong University

phase contrast imaging technique has been improved promptly in recent years. Among these techniques in-line phase-contrast imaging is widely used. Various algorithms for in-line phase retrieval have been proposed so far such as TIE(transport of intensity equation), CTF(contrast transfer function), first born-approximations, GSF(Gerchberg-Saxton-Fienup), etc. Bronnikov's algorithm(BA) is a type of linear algorithm that is simple and efficient. But it can only be used without absorption situations. In this paper, an improved algorithm based on BA was presented. The approach adds Δφ(x,y) to the phase map φ_b(x,y) retrieved by BA to make the reconstructed phase map more precise. Further, the approach was evaluated on simulated images and confirmed to be accurate at higher absorption rates.

关键词： in-line phase contrast imaging phase retrieval improved algorithm

Near-field x-ray phase contrast imaging and phase retrieval algorithm

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Chinese Physics B 2005年第4期14卷 796-801页

作者：朱化凤谢红兰高鸿奕陈建文李儒新徐至展 ShanghaiInstituteofOpticsandFineMechanics ChineseAcademyofSciencesShanghai201800China

Theoretical analyses of x-ray diffraction phase contrast imaging and near field phase retrieval method are presented.A new variant of the near field intensity distribution is derived with the optimal phase imaging distance and spatial frequency of object taken into account. Numerical examples of phase retrieval using simulated data are also given. On the above basis, the influence of detecting distance and polychroism of radiation on the phase contrast image and the retrieved phase distribution are discussed. The present results should be useful in the practical application of in-line phase contrast imaging.

关键词： x-ray phase contrast imaging phase retrieval diffraction

X-ray volumetric quantitative phase imaging by Foucault differential filtering with linear scanning

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Chinese Optics Letters 2023年第1期21卷 120-124页

作者： Young-Sung Park Jieun Hong Jaeho Choi Photonics Laboratory Department of PhysicsDankook UniversityCheonan 31116Republic of Korea Center for Basic Science Research at DKU Dankook UniversityCheonan 31116Republic of Korea

Non-interferometric X-ray quantitative phase imaging(XQPI),much simpler than the interferometric scheme,has provided high-resolution and reliable phase-contrast images.We report on implementing the volumetric XQPI images using concurrent-bidirectional scanning of the orthogonal plane on the optical axis of the Foucault differential filter;we then extracted data in conjunction with the transport-intensity equation.The volumetric image of the laminate microstructure of the gills of a fish was successfully reconstructed to demonstrate our XQPI method.The method can perform 3D rendering without any rotational motion for laterally extended objects by manipulating incoherent X-rays using the pinhole array.

关键词： X-ray imaging phase contrast imaging Foucault differential filter transport-intensity equation

An ART iterative reconstruction algorithm for computed tomography of diffraction enhanced imaging

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Chinese Physics C 2009年第11期33卷 975-980页

作者：王振天张丽黄志峰康克军陈志强方侨光朱佩平 Department of Engineering Physics Tsinghua University Key Laboratory of Particle & Radiation imaging(Tsinghua University)Ministry of Education Beijing Synchrotron Radiation Facility Institute of High Energy Physics

X-ray diffraction enhanced imaging （DEI） has extremely high sensitivity for weakly absorbing low- Z samples in medical and biological fields. In this paper, we propose an Algebra Reconstruction Technique （ART） iterative reconstruction algorithm for computed tomography of diffraction enhanced imaging （DEI-CT）. An Ordered Subsets （OS） technique is used to accelerate the ART reconstruction. Few-view reconstruction is also studied, and a partial differential equation （PDE） type filter which has the ability of edge-preserving and denoising is used to improve the image quality and eliminate the artifacts. The proposed algorithm is validated with both the numerical simulations and the experiment at the Beijing synchrotron radiation facility （BSRF）.

关键词： diffraction enhanced imaging algebra reconstruction technique phase contrast imaging