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2008 International Conference on Optical Instruments and Technology

作者： Huaiyu CAI~*,Chao FANG,Liqiang FAN,Zhanhua HUANG,Yinxin ZHANG (Key Laboratory of Opto-electronics Information Science and Technology, Ministry of Education,College of Precision Instrument and Opto-electronics Engineering, Tianjin University,Tianjin 300072,China )

The phase mask plays a key role in wavefront coding *** order to find the phase coding device with better performance,a new kind of phase mask-five times phase mask is proposed,based on cubic phase mask in common use, and its coding properties are studied in the *** of all,the reason of depressing spherical aberration is analyzed by deriving the asymptotic solution to OTF of the wavefront coding systems with five times phase *** then we compare the effects of inhibition of spherical aberration when place the cubic and five times phase mask respectively. Finally,the experimental simulation is *** results show that on the specific threshold(MTF=0.1)the normalized bandwidth of the system with five times phase mask can be reached 3 times of that with the cubic one;at the same characteristic frequency(h=0.5),the MTF value is 2 times of that in system with cubic *** the MTF consistency in the low frequency region and the PTF consistency in the high frequency region of the system with a five times phase mask are better than those with a cubic one in condition of different spherical *** with the cubic phase mask,the five times phase mask performs better in inhibition of spherical aberration.

关键词： wavefront coding five times phase mask cubic phase mask OTF MTF PTF inhibition of spherical aberration consistency

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Using wavefront coding in presence of non-symmetric aberrations

Using Wavefront Coding in presence of non-symmetric aberrati...

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Euro-American Workshop on Information Optics

作者： Martin Lariviere-Bastien Simon Thibault Dept. de physique de genie physique et d'optique Laval University

ISBN: (纸本)9781467320009

wavefront coding is a hybrid technology designed to increase depth of field of conventional optics but it can also be used to compensate for other aberration and ease tolerancing. The goal of our research is to apply this technology to panoramic imager. Panoramic imagers suffer from an increase level of aberration due to the large field of view and it is also subject to a special tolerance process. They also typically have a wide variation of the point spread function (PSF) across the field of view and suffer from non-symmetric aberration like coma and astigmatism. To obtain the best result using wavefront coding, the PSF should be as invariant as possible over the whole field of view. Asymmetric phase masks, when used in systems having non-negligible asymmetric aberrations, generate variations in the final image quality. For that reason, a model that predicts the final image quality of wavefront coded system is needed. The possibility of using two surfaces for wavefront coding has been studied. The final results were analysed using a variance based image quality criterion. From these results, it is possible to optimize phase mask for panoramic imager and predict the resulting image quality.

关键词： wavefront coding Wide angle Panomorph

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A high-precision binocular 3D reconstruction system based on depth-of-field extension and feature point guidance

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MEASUREMENT 2025年 248卷

作者： Lyu, Yuxing Liu, Zongming Wang, Junhua Jiang, Ying Li, Yidan Li, Xinglong Kong, Lingbao Li, Jing Xu, Min Fudan Univ Dept Opt Sci & Engn Shanghai 200438 Peoples R China Fudan Univ Inst Optoelect Shanghai Frontiers Sci Res Base Intelligent Optoel Shanghai 200438 Peoples R China Shanghai Aerosp Control Technol Inst Shanghai 201109 Peoples R China Shanghai Key Lab Space Intelligent Control Technol Shanghai 201109 Peoples R China

Limited depth of field (DOF) restricts high-precision 3D reconstruction in large volumes using binocular stereo vision. wavefront coding (WFC) generates intermediate images with consistent point spread function (PSF) over a large DOF that are processed into clear final images by decoding algorithms, making it ideal for large-DOF 3D reconstruction. In this paper, we develop a binocular stereo vision system based on WFC. By combining back propagation (BP) neural network with adaptive genetic algorithm (AGA), the system addresses the problems of high computational cost and high instability of traditional calibration methods. Using calibration results, a twostep correction method for binocular distortion and epipolar correction guided by feature points is designed, which improves matching efficiency and accuracy. Combined with an end-to-end stereo matching network, our system achieves high-precision 3D reconstruction within a depth range of 0.3 m- 2.3 m, significantly enhancing reconstruction stability and accuracy. Additionally, the average total execution time from image acquisition to final 3D reconstruction is approximately 0.223 s, demonstrating the system's efficiency for real-time applications.

关键词： 3D reconstruction Binocular stereo vision wavefront coding Depth of field Camera calibration Feature point

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Lensless broadband diffractive imaging with improved depth of focus: wavefront modulation by multilevel phase masks

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JOURNAL OF MODERN OPTICS 2019年第3期66卷 335-352页

作者： Katkovnik, Vladimir Ponomarenko, Mykola Egiazarian, Karen Tampere Univ Technol Lab Signal Proc Korkeakoulunkatu 10 FI-33720 Tampere Finland

This paper introduces a novel lensless full colour diffractive computational imaging system with a planar Multilevel Phase Mask (MPM) as a diffractive optical element (DOE). The novelty concerns: a methodology of MPM design for improved depth of focus (DoF);design of PSFs for RGB imaging and an inverse imaging algorithm with sparse colour image modelling simultaneous for all RGB channels. MPMs are step-wise invariant. The cubic wavefront coding (WFC) is incorporated in MPMs with optimization of number of levels and width of invariant steps. This design of MPM makes the system robust with respect to defocus (improves DoF) and diminish chromatic aberrations typical for DOEs. Broadband multichannel test-images are exploited for design and testing of the lensless system. We consider two alternative optical setups: Wavelength Multiplexing (WM) and Wavelength Division (WD). In WM, the light beam is broadband multichannel with light sources radiating all wavelengths simultaneously and a CMOS sensor is equipped with a Bayer colour filter array (CFA) for registration of spectral measurements. In this setup, a single MPM is designed for the broadband multichannel light beams. In WD, separate exposures of RGB channels are registered by a broadband grey-scale CCD sensor. Different MPMs are designed for each of the RGB channels. Simulation experiments demonstrate the essentially extended DoF of the designed lensless systems and the advanced accuracy and quality of imaging with respect to the corresponding WM and WD systems with refractive lenses. Due to robustness of the designed lensless system to chromatic aberrations, this advantage has a place even with respect to the lens-system.

关键词： Multilevel diffractive optical elements multilevel phase mask design wavefront coding extended depth of focus computational imaging chromatic aberrations inverse imaging

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Learning Optimal wavefront Shaping for Multi-Channel Imaging

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IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 2021年第7期43卷 2179-2192页

作者： Nehme, Elias Ferdman, Boris Weiss, Lucien E. Naor, Tal Freedman, Daniel Michaeli, Tomer Shechtman, Yoav Technion Israel Inst Technol Viterbi Fac Elect Engn Biomed Engn Dept IL-3200003 Haifa Israel Technion Israel Inst Technol Lorry I Lokey Ctr Life Sci & Engn IL-3200003 Haifa Israel Technion Israel Inst Technol Russel Berrie Nanotechnol Inst Biomed Engn Dept IL-3200003 Haifa Israel Technion Israel Inst Technol Russel Berrie Nanotechnol Inst Lorry I Lokey Ctr Life Sci & Engn IL-3200003 Haifa Israel Technion Israel Inst Technol Biomed Engn Dept IL-3200003 Haifa Israel Google Res IL-3508504 Haifa Israel Technion Israel Inst Technol Viterbi Fac Elect Engn IL-3200003 Haifa Israel

Fast acquisition of depth information is crucial for accurate 3D tracking of moving objects. Snapshot depth sensing can be achieved by wavefront coding, in which the point-spread function (PSF) is engineered to vary distinctively with scene depth by altering the detection optics. In low-light applications, such as 3D localization microscopy, the prevailing approach is to condense signal photons into a single imaging channel with phase-only wavefront modulation to achieve a high pixel-wise signal to noise ratio. Here we show that this paradigm is generally suboptimal and can be significantly improved upon by employing multi-channel wavefront coding, even in low-light applications. We demonstrate our multi-channel optimization scheme on 3D localization microscopy in densely labelled live cells where detectability is limited by overlap of modulated PSFs. At extreme densities, we show that a split-signal system, with end-to-end learned phase masks, doubles the detection rate and reaches improved precision compared to the current state-of-the-art, single-channel design. We implement our method using a bifurcated optical system, experimentally validating our approach by snapshot volumetric imaging and 3D tracking of fluorescently labelled subcellular elements in dense environments.

关键词： Imaging Three-dimensional displays Microscopy Location awareness Optical microscopy Optical imaging Optical diffraction Computational microscopy wavefront coding deep neural networks end-to-end optimization

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Imaging quality improvement for wavefront colding system with radially symmetrical phase mask

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OPTICAL AND QUANTUM ELECTRONICS 2023年第6期55卷 1-11页

作者： Le, Vannhu Le, Minhthai Le Quy Don Tech Univ 236 Hoang Quoc Viet St Hanoi Vietnam

In this paper, we introduce the novel method to improve the image quality for the optical imaging system with the radially symmetrical phase masks. By introducing 0-pi phase mask into the radially symmetrical one, the new phase mask is generated, which produces the dark-shape point spread function. By rotating this phase mask with the amplitude mask for different angles, the point spread function is still rotated by the same angle. Moreover, the digital processing is used to restore the high-quality image. The simulation results demonstrated the effectiveness of the proposed method in comparison to the previously radially symmetrical phase mask.

关键词： wavefront coding Phase mask Digital processing

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Tunable wavefront coded imaging system based on detachable phase mask: Mathematical analysis, optimization and underlying applications

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OPTICS COMMUNICATIONS 2014年 326卷 35-42页

作者： Zhao, Hui Wei, Jingxuan Chinese Acad Sci Xian Inst Opt & Precis Mech Xian 710119 Peoples R China Xidian Univ Sch Comp Sci & Technol Xian 710071 Peoples R China

The key to the concept of tunable wavefront coding lies in detachable phase masks. Ojeda-Castaneda et al. (Progress in Electronics Research Symposium Proceedings, Cambridge, USA, July 5-8, 2010) described a typical design in which two components with cosinusoidal phase variation operate together to make defocus sensitivity tunable. The present study proposes an improved design and makes three contributions: (1) A mathematical derivation based on the stationary phase method explains why the detachable phase mask of Ojeda-Castaneda et al tunes the defocus sensitivity. (2) The mathematical derivations show that the effective bandwidth wavefront coded imaging system is also tunable by making each component of the detachable phase mask move asymmetrically. An improved Fisher information-based optimization procedure was also designed to ascertain the optimal mask parameters corresponding to specific bandwidth. (3) Possible applications of the tunable bandwidth are demonstrated by simulated imaging. (C) 2014 Elsevier B.V. All rights reserved.

关键词： wavefront coding Detachable phase mask Tunable bandwidth

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Odd symmetrical square-root phase mask to extend the depth of field in wavefront-coded imaging systems

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OPTIK 2015年第22期126卷 3463-3466页

作者： Van Nhu Le Chen, Shouqian Fan, Zhigang Zhang, Wang Harbin Inst Technol Res Ctr Space Opt Engn Harbin 150001 Heilongjiang Peoples R China

Extend-the-depth-of-field imaging can be achieved by wavefront coding technique, which inserts an odd symmetrical phase mask into the pupil plane to generate the invariant imaging property over a wide range of defocus. Obtaining the low sensibility to defocus for wavefront coding systems depends on designing a proper phase profile. Here we proposed a phase mask combining the power function with the square-root function to maximize the invariant imaging property to defocus. Judging by defocused modulation transfer function (MTF) and Hilbert space angle, numerical comparisons with the cubic mask, exponential mask and improved logarithmic mask prove the superiority of proposed square-root phase mask in extending the depth of field. (C) 2015 Elsevier GmbH. All rights reserved.

关键词： wavefront coding Square-root phase mask Depth-of-field Modulation transfer function

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Off-axis performance analysis of wavefront coded imaging system

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OPTICAL REVIEW 2009年第2期16卷 126-128页

作者： Chang, Chuan-Chung Angot, Ludovic Tsao, Hsiao-Yue Chang, Chir-Weei Lee, Cheng-Chung Natl Cent Univ Dept Opt & Photon Taipei Taiwan Ind Technol Res Inst Elect & Optoelect Res Labs Hsinchu Taiwan

Point spread functions at different field angles and phase deviations of the cubic mask are used for image restoration to analyze the off-axis performance of a wavefront coded imaging system.

关键词： deconvolution wavefront coding cubic phase off axis shift invariant

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wavefront Coded zoom lens system

Wavefront Coded zoom lens system

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3rd Conference on Zoom Lenses

作者： Prischepa, IA Dowski, ER CDM Opt Inc Boulder CO 80303 USA

ISBN: (纸本)0819442011

In this paper a fast wide angle two element wavefront Coded zoom lens is discussed. A traditional optics-only fast wide angle two element zoom system can not provide good imaging quality over a large field of view. wavefront coding techniques allow us to correct misfocus aberrations thus simplifying the optical system design while also providing good imaging quality. Imaging with an optical/digital system requires digital image processing that removes the spatial effect of wavefront coding.

关键词： wavefront coding zoom lens digital image processing digital filter

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