Article
Optics
Qian Chen, Zhijie Tan, Hong Yu, Shensheng Han
Summary: Ghost imaging based on high-order correlation of optical field has been rapidly developed and extended to the x-ray region. However, limited photon flux results in severe image deterioration. In this study, Fourier-transform ghost imaging with super-Rayleigh speckles is proposed to achieve high-quality ghost imaging at a low photon flux level. The super-Rayleigh speckles were designed using the direct binary search algorithm to optimize binary modulating screens. Experimental results show that speckle contrast can be greatly enhanced and high-visibility Fourier-transform diffraction patterns of the sample can be obtained. This method is of great importance for high-resolution imaging in photon-limited scenarios, especially for laboratory x-ray systems.
Article
Physics, Multidisciplinary
Yi Zhang, Yunhe Zhang, Chen Chang, Shuai Sun, Weitao Liu
Summary: Multiple description coding ghost imaging is an imaging method with advantages in challenging scenarios. By using illumination with different coding patterns, it can produce satisfactory images even when the signal is distorted or lost, providing a positive boost for practical applications of ghost imaging.
FRONTIERS IN PHYSICS
(2023)
Article
Mathematics, Interdisciplinary Applications
Tieyu Zhao, Yingying Chi
Summary: This study investigates the discrete fractional Fourier transform and its extended definition, the multiweighted-type fractional Fourier transform, and proves its unitarity. By using basic functions for discussion, it is found that the effective weighting term of the M-WFRFT is only four terms, different from the M terms described in the definition. The analysis of program code reveals inaccuracies in previous works based on MATLAB for unitary verification.
FRACTAL AND FRACTIONAL
(2021)
Article
Physics, Multidisciplinary
Xing-Yu Chen, Xin Zhou, Xing Bai, Zhan Yu, Yu-Jie Wang, Xin-Jia Li, Yang Liu, Ming-Ze Sun
Summary: Ghost imaging, a hotspot in the imaging field, has various systems based on different principles. Research shows that Fourier ghost imaging and sinusoidal ghost imaging are equivalent in principle, and combining their characteristics can improve the anti-noise performance and imaging efficiency.
ACTA PHYSICA SINICA
(2023)
Article
Mathematics, Applied
Xinyu Cheng, Dong Li, Wen Yang
Summary: This paper demonstrates the equivalence between the classical Helmholtz equation and the fractional Helmholtz equation of arbitrary order, and improves upon a recent study by Guan, Murugan, and Wei in the field of Helmholtz solutions for the Fractional Laplacian and related operators.
COMMUNICATIONS IN CONTEMPORARY MATHEMATICS
(2023)
Article
Physics, Multidisciplinary
Yi Kang, Leihong Zhang, Hualong Ye, Dawei Zhang, Songlin Zhuang
Summary: A novel ghost imaging-based optical cryptosystem for multiple images is proposed using the integral property of the Fourier transform. Modulation patterns related to plaintext images are constructed to achieve encrypted transmission of multiple images, providing a new idea for optical information encryption. The feasibility, security, and robustness of the scheme are verified through experiments and simulations, demonstrating high scalability and broad application prospect.
Article
Optics
Sen Xiang, Li Liu, Huiping Deng, Jin Wu, You Yang, Li Yu
Summary: The paper introduces phase light field (PLF) and re-formatted phase-epipolar-plane-images (phase EPIs) for depth estimation, and proposes a global cost minimization framework. The beetle antennae search (BAS) optimization algorithm is utilized to find the optimal line for depth estimation. The proposed method achieves significant acceleration compared to state-of-the-art methods while maintaining comparable depth quality.
Article
Mathematics, Interdisciplinary Applications
Tieyu Zhao, Yingying Chi
Summary: In this paper, the authors utilize quantum Fourier transform and quantum phase estimation to achieve quantum fractional Fourier transform, and establish the relationship between quantum fractional Fourier transform and a classical algorithm. The flaws in the definitions of multi-fractional Fourier transform are observed, and the circuit of quantum fractional Fourier transform and the reasons for the observed defects are analyzed.
FRACTAL AND FRACTIONAL
(2023)
Article
Mathematics
Tieyu Zhao, Tianyu Yang, Yingying Chi
Summary: This paper introduces the quantum weighted fractional Fourier transform (QWFRFT), opening up new possibilities for quantum signal processing implementations.
Article
Mathematics, Interdisciplinary Applications
Hui Zhao, Bing-Zhao Li
Summary: This brief report examines the problem of unlimited sampling of high dynamic non-bandlimited signals in the Fourier domain based on the fractional Fourier transform. It proposes a mathematical signal model for unlimited sampling and uses the annihilation filtering method to estimate arbitrary folding time. A novel fractional Fourier domain unlimited sampling theorem is obtained.
FRACTAL AND FRACTIONAL
(2023)
Article
Engineering, Electrical & Electronic
Gaowa Huang, Feng Zhang, Ran Tao
Summary: The short-time fractional Fourier transform (STFRFT) is a powerful tool for processing signals with fractional frequencies that vary over time. However, the existing discrete algorithms are not suitable for real-time applications that require recalculating the STFRFT at each or several samples. To solve this problem, a new sliding algorithm, called the sliding STFRFT, is proposed. It directly computes the STFRFT at the given time using the output result of the previous time step, significantly reducing computation complexity. The proposed algorithm has been shown to have the lowest computational cost among existing STFRFT algorithms.
IEEE SIGNAL PROCESSING LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Deyun Wei, Jun Yang
Summary: The discrete fractional Fourier transform is a useful tool in non-stationary signal processing. This paper proposes a two-dimensional sparse fractional Fourier transform (2D SFRFT) algorithm, which achieves the lowest runtime and sample complexity compared to existing methods. The algorithm is improved to be robust by analyzing errors due to noises, and its effectiveness is demonstrated in various applications.
Article
Optics
Jie Xu, Changjun Min, Yuquan Zhang, Jielei Ni, Gengwei Cao, Qianyi Wei, Jianjun Yang, Xiaocong Yuan
Summary: In this study, a wide-field single-probe structured light microscopy (SPSLM) is proposed and built to image the ultrafast three-dimensional topography evolution induced by femtosecond (fs) lasers. The SPSLM achieves high-resolution imaging in both spatial and temporal domains by utilizing a single imaging frame and a structured probe pulse. The technology is of great significance for studying ultrafast dynamics in fields such as fs laser ablation and material science.
PHOTONICS RESEARCH
(2022)
Article
Mathematics, Applied
Ramanathan Kamalakkannan, Rajakumar Roopkumar, Ahmed Zayed
Summary: In this paper, a short-time coupled fractional Fourier transform (SCFRFT) is introduced using the kernel of the coupled fractional Fourier transform (CFRFT). The authors prove its satisfaction of Parseval's relation, derive its inversion and addition formulas, and characterize its range on L-2(R-2). The study also includes analysis of its time delay and frequency shift properties, and concludes with an uncertainty principle for both the coupled fractional Fourier transform and short-time coupled fractional Fourier transform.
FRACTIONAL CALCULUS AND APPLIED ANALYSIS
(2021)
Article
Mathematics, Applied
Wen-Biao Gao
Summary: In this paper, different uncertainty principles for hypercomplex functions associated with the fractional Fourier transform (FRFT) are investigated. The inverse formula and Plancherel theorem of the FRFT are obtained. A new uncertainty principle for the FRFT of hypercomplex functions in the time and FRFT domains is explored, and an uncertainty principle in two FRFT domains is also derived. The correctness of the theorems is demonstrated using examples.
FRACTIONAL CALCULUS AND APPLIED ANALYSIS
(2023)
Article
Optics
Tomohiro Shirai
Article
Optics
Tomohiro Shirai
OPTICS COMMUNICATIONS
(2016)
Article
Optics
Tomohiro Shirai
Article
Optics
Tomohiro Shirai, Ari T. Friberg
Article
Instruments & Instrumentation
Hiromitsu Furukawa, Hidenobu Arimoto, Tomohiro Shirai, Sotaro Ooto, Masanori Hangai, Nagahisa Yoshimura
APPLIED SPECTROSCOPY
(2012)
Article
Optics
Henri Kellock, Tero Setala, Tomohiro Shirai, Ari T. Friberg
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION
(2012)
Article
Optics
Tomohiro Shirai, Henri Kellock, Tero Setala, Ari T. Friberg
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION
(2012)
Article
Optics
Tomohiro Shirai, Ari T. Friberg
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION
(2014)
Article
Optics
Kohei Takeno, Tomohiro Shirai
OPTICS COMMUNICATIONS
(2012)
Article
Optics
Tomohiro Shirai, Ari T. Friberg
Article
Optics
Henri Kellock, Tero Setala, Ari T. Friberg, Tomohiro Shirai
Article
Optics
Tomohiro Shirai, Ari T. Friberg
Article
Optics
Tomohiro Shirai, Ari T. Friberg
Summary: The study introduces a novel approach called quantum-mimetic optical coherence tomography (OCT) combined with wavefront shaping, which allows high-resolution cross-sectional imaging through strongly scattering media. Experimental validation demonstrates the successful and efficient acquisition of one-dimensional cross-sectional images behind a diffuser plate using this technique.
Article
Optics
Tomohiro Shirai, Ari T. Friberg
Summary: The proposed method of measuring the spatial coherence of light through temporal modulation of a double slit on a digital micromirror device is generally insensitive to background light, eliminating the need for its suppression or subtraction. The visibility of the interference fringe pattern can be enhanced by modulating only one of the two slits, making it more convenient and accurate to measure the spatial coherence of even faint light.
Proceedings Paper
Engineering, Electrical & Electronic
Piotr Ryczkowski, Jari Turunen, Tomohiro Shirai, Ari Friberg, Goery Genty
2014 16TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON)
(2014)
