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Coupled Dual-Frequency phase-shifting Coder for Precise Rotated Angle Representation in Oriented Object Detection

IEEE GEOSCIENCE AND REMOTE SENSING LETTERS 2024年 21卷 1页

作者： Liu, Fei Chen, Renwen Zhang, Junyi Ding, Shanshan Liu, Hao Ma, Shaofei Xing, Kailing Nanjing Univ Aeronaut & Astronaut Coll Aerosp Engn State Key Lab Mech & Control Aerosp Struct Nanjing 210016 Peoples R China ZTE Corp Wired Prod Res & Dev Inst Syst Prod Wired Prod Operat Div Hardware Dev Dept 4 Nanjing 210037 Peoples R China

The classically oriented object detection method often suffers boundary discontinuity and square-like problems, hindering the model's ability to predict orientation accurately. Therefore, in this letter, we introduce a novel angle representation scheme named coupled dual-frequency phase-shifting coder (CDFP) which draws inspiration from optical measurement technology to address the aforementioned issues. Specifically, in the angle encoding stage, we represent the ground-truth (GT) rotation angle as a combination of two five-step phase-shifting at different frequencies and use this representation to supervise the learning of the model's angle branch. In the angle decoding stage, alongside utilizing the corresponding dual-frequency phase-shifting decoding and unwrapping method, we impose additional constraints on the decoding angle range for predicted square-like objects. Extensive experiments on three challenging aerial image datasets using different detectors prove the effectiveness of our approach. Specifically, our RetinaNet-CDFP achieves an average improvement of 2.16% AP50 and 6.83% AP75 on DOTA, and when combined with RTMDet, our RTMDet-R-m-CDFP achieves state-of-the-art (SOTA) detection performance on DIOR-R and DOTA, with 70.11% and 78.77% AP50, respectively. Our codes will be released at https://***/liufeinuaa/***.

关键词： Aerial image deep learning oriented object detection phase-shifting algorithm remote sensing rotated angle coder

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Design of the phase-shifting algorithm for flatness measurement of a mask blank glass

Design of the phase-shifting algorithm for flatness measurem...

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Conference on Metrology, Inspection, and Process Control for Microlithography XXVIII

作者： Kim, Yangjin Hibino, Kenichi Sugita, Naohiko Mitsuishi, Mamoru Univ Tokyo Bunkyo Ku Tokyo 1138656 Japan AIST Tsukuba Ibaraki 3058564 Japan

ISBN: (纸本)9780819499738

Nonlinearity and non-uniformity of phase-shifts significantly contribute to the error of the evaluated phase in phase-shifting interferometry. However, state of the art error-compensating algorithms can counteract the linear mis-calibration and first-order nonlinearity associated with the phase-shift. We describe an error expansion method that is utilized to construct a phase-shifting algorithm that can compensate the second-order nonlinearity and non-uniformity of phase-shifts. The conditions for eliminating the effect of second-order nonlinearity and non-uniformity of phase-shifts are given as a set of linear equations for the sampling amplitudes. We developed a novel 11-sample phase-shifting algorithm that can compensate for the second-order nonlinearity and non-uniformity of phase-shifts and is robust up to a 4th harmonic. Experimental results show that the surface shape of a transparent plate could be measured with a precision of 1 nm, over the 120-mm-diameter aperture.

关键词： Interferometry mask glass flatness phase-shifting algorithm phase shift error coupling

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Harmonics suppression in frequency domain for fringe projection profilometry with arbitrary phase shifts

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OPTICS COMMUNICATIONS 2025年 576卷

作者： Lin, Shuai Zhu, Jianli Guo, Hongwei Shanghai Univ Dept Precis Mech Engn Lab Appl Opt & Metrol Shanghai 200444 Peoples R China China Elect Technol Grp Corp Res Inst 30 Chengdu 610041 Peoples R China

In phase-shifting fringe projection profilometry, nonlinearities of the used devices affect measurement accuracy by induing harmonics in fringe signals. The resulting errors are manifested as ripple artifacts in the measured phase maps. Especially when phase shifts are not uniform, the error artifacts have unpredictable profiles and complicated frequency components thus being not easy to eliminate. To solve this problem, this paper suggests a method for suppressing effects of fringe harmonics when using arbitrary phase shifts. For doing it, this paper derives the frequency transfer function that explicitly represents the response of the phase-shifting algorithm to each order of fringe harmonics, and then uses this function to deduce a method that allows one to estimate the coefficients of harmonics from spectrum of the calculated complex fringe pattern. By iteratively subtracting off the estimated harmonics from the calculated complex fringe pattern, fringe phases are calculated accurately. Simulation and experimental results demonstrate that this method significantly suppresses the influence of fringe harmonics on measurement results and, simultaneously, it preserves edges and details of the measured object from being blurred.

关键词： Fringe projection profilometry phase-shifting algorithm Fringe harmonics Error correction

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Generalized Technique for Separating Nonsinusoidal Errors in Fringe Projection Profilometry With Arbitrary phase Shifts

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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 2024年 73卷 1页

作者： Zhu, Jianli Zhu, Huijie Guo, Hongwei Shanghai Univ Dept Precis Mech Engn Lab Appl Opt & Metrol Shanghai 200444 Peoples R China

In phase-shifting fringe projection profilometry, the nonsinusoidal profile of fringes is one of the most crucial error-inducing factors. Especially, when using nonuniform phase shifts, the complex response of the phase-shifting algorithm to fringe harmonics makes the nonsinusoidal errors difficult to eliminate. To overcome this problem, this article analytically deduced a general phase error function related to the fringe harmonics when using arbitrary phase shifts and then exploited this function to derive a blind method for separating the nonsinusoidal errors from the measured phase maps. In implementation, this method calculates a coarse phase map first by using the least-squares algorithm from captured fringe patterns and then filters this calculated phase map to isolate its artifacts caused by the nonsinusoidal errors. By fitting these isolated artifacts to the phase error function with the outliers excluded using the three-sigma criterion, the coefficients related to the fringe harmonics are estimated. Using these coefficients allows one to compensate for the nonsinusoidal errors at each pixel through fixed-point iterations or, more efficiently, by using a postestablished look-up table. This proposed method offers several merits over others. First, by taking advantage of the model with arbitrary phase shifts, this method is flexible in practical measurements that may use various types of light sources and phase-shifters. Meanwhile, it has generality in principle, making it easy to derive a simplified error-suppressing algorithm adaptive to a special case of using uniform or selected nonuniform phase shifts. Second, it is a purely blind method that allows users to eliminate the effects of fringe harmonics depending on very few (e.g., 3 or 4) fringe patterns without a calibration or a priori knowledge of the light source. Third, it effectively preserves edges and detailed features of the measured surface from being blurred. The effectiveness and feasibility of

关键词： Harmonic analysis Power harmonic filters phase measurement Measurement uncertainty Light sources Calibration Cameras Fringe projection technique nonsinusoidal error phase error correction phase-shifting algorithm

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Noncontact surface profiling using optical interferometric microscopy

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OPTICAL ENGINEERING 2024年第2期63卷 023104-023104页

作者： Palacios, Diego Zhai, Bowen Wang, Michael R. Univ Miami Dept Elect & Comp Engn Coral Gables FL 33124 USA

. We report the use of noncontact optical interferometric microscopy for surface topographic profiling. A Linnik optical configuration is used to create interferograms of an object's surface. When the coherence condition between the two beams is met, the phase information of the object's surface can be extracted to establish its topographic contour image. Using four pi /4 phase-shifted images, with the synchronization of a piezoelectric actuator reference mirror positioning, the present single camera optical interferometric microscope can reconstruct a surface topography with a field of view of 312 mu mx234 mu m, axial resolution of 3.31 nm, lateral resolution of 488 nm, and maximum topography height of 270 nm.

关键词： optical interferometric microscopy surface profiling phase-shifting algorithm phase map

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Two-frame wavefront reconstruction method with nonlinear optimization for Ronchi lateral

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OPTICS COMMUNICATIONS 2024年 559卷

作者： Shi, Runzhou Liu, Huiwen Shao, Yuqi Zhang, Tian Bai, Jian Zhejiang Univ State Key Lab Extreme Photon & Instrumentat Hangzhou 310027 Peoples R China Zhejiang Univ Coll Opt Sci & Engn Hangzhou 310027 Peoples R China Zhejiang Univ ZJU Hangzhou Global Sci & Technol Innovat Ctr Hangzhou 311215 Peoples R China

Ronchi lateral shearing interferometry is widely applied in wavefront measurement of advanced lithography tools. In Ronchi lateral shearing interferometry, higher-order diffraction beam interference is a common challenge, currently mitigated by introducing more phase shifts, resulting in extended measurement times and added errors. In this study, we propose a nonlinear optimization approach that combines a 2-frame phase-shifting algorithm to suppress the influence of high diffraction orders, reducing the required number of phase shifts by more than 75%. We formulate a numerical model that aligns with the interferometry, construct a highly robust error function, and enable high-precision wavefront reconstruction by optimizing Zernike coefficients. The accuracy and robustness of the proposed method are verified through simulations and experiments.

关键词： Ronchi lateral shearing interferometry Wavefront reconstruction phase-shifting algorithm Nonlinear optimization

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Interferometric thickness measurement of glass plate by phase-shifting analysis using wavelength scanning with elimination of bias phase error

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OPTICAL REVIEW 2021年第1期28卷 48-57页

作者： Kim, Sungtae Kim, Yangjin Shin, Sung-Chul Hibino, Kenichi Sugita, Naohiko Pusan Natl Univ Sch Mech Engn 2Busandaehak Ro 63beon Gil Busan 46241 South Korea Pusan Natl Univ Dept Naval Architecture & Ocean Engn 2Busandaehak Ro 63beon Gil Busan 46241 South Korea Natl Inst Adv Ind Sci & Technol 1-1-1 Umezono Tsukuba Ibaraki 3058563 Japan Univ Tokyo Dept Mech Engn Bunkyo Ku 7-3-1 Hongo Tokyo 1138656 Japan

phase-shifting fringe analysis using wavelength scanning has been broadly applied to the interferometric profiling of the thickness variation of glass plates. However, the nonlinear phase shifting can cause bias error during wavelength scanning. In this study, the bias error in the calculated phase was formulated by Taylor series expansion. Using the formulation, a novel 15-sample algorithm of a partially negative window was derived to enable compensation for the bias phase error. The new 15-sample algorithm was visualized by the algorithm polynomial on the complex plane and Fourier description in the frequency domain. The bias error suppression capability of the developed algorithm was examined by using the numerical simulation. Finally, the proposed algorithm was used in conjunction with a large-aperture Fizeau interferometer to examine the thickness variation of a glass parallel plate.

关键词： Bias phase error Fizeau interferometer phase-shifting algorithm Thickness Glass plate Wavelength scanning

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phase-shifting ESPI Micro-deformation Testing algorithm and Experimental Research 7

Phase-shifting ESPI Micro-deformation Testing Algorithm and ...

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7th International Conference on Optical and Photonic Engineering (icOPEN)

作者： Su, Hanyue Yu, Yingjie Chen, Dingfu Shanghai Univ Dept Precis Mech Engn Shanghai 200072 Peoples R China Lab Appl Opt & Metrol Shanghai 200072 Peoples R China

ISBN: (数字)9781510631601

ISBN: (纸本)9781510631601

Electronic Speckle Interferometry (ESPI) is a common method for deformation measurements by introducing a phase shift technique. The traditional method needs to subtract the distribution of the phase before and after deformation to get the deformation information. During this process, the noise of the object wavefront will partially remain in the deformation signal. In order to solve this problem, this paper proposes a 5+5 phase-shifting algorithm to suppress the influence of the error from the calculation. In this algorithm, the deformed phase map is directly obtained by combining the interferograms before and after the deformation. Several experiments have been carried out to verify this method. Finally, the results show a better characteristic to quantify deformation than the traditional method. In addition, the algorithm also has better redundancy.

关键词： ESPI micro-deformation phase-shifting algorithm

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Motion-induced error reduction for phase-shifting profilometry with phase probability equalization

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OPTICS AND LASERS IN ENGINEERING 2022年 156卷

作者： Wang, Yuwei Cai, Jiaxu Liu, Yuankun Chen, Xiangcheng Wang, Yajun Anhui Agr Univ Coll Engn Hefei 230036 Peoples R China Anhui Prov Engn Lab Intelligent Agr Machinery & Eq Hefei 230036 Peoples R China Sichuan Univ Coll Elect & Informat Engn Chengdu 610065 Peoples R China Anhui Univ Sch Artificial Intelligence Hefei 230039 Peoples R China

phase-shifting algorithms have been widely used for three-dimensional (3D) shape measurement. However, when measuring moving objects, the object motion may distort the linear phase and lead to the phase error. This paper presents an effective phase probability equalization (PPE) method for motion-induced error reduction, which directly equalizes the distorted phase to estimate the linear phase. In general, adequate sampling pixels are needed to compute the accurate phase probability (PP). This paper further presents an improved shifted-phase probability equalization (SPE) method, which combines the original phase and its kappa-shifted phase to double the sampling pixels. Both simulations and experiments have been conducted to measure objects moving in z direction, and their results validate that the proposed PPE and SPE methods could effectively compensate the motion-induced error.

关键词： phase-shifting algorithm 3D shape measurement phase probability Motion-induced error

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Quantum imaging beyond the standard-quantum limit and phase distillation

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NEW JOURNAL OF PHYSICS 2024年第2期26卷 023018页

作者： Schaffrath, Simon Derr, Daniel Graefe, Markus Giese, Enno Tech Univ Darmstadt Inst Angew Phys Fachbereich Phys Schlossgartenstr 7 D-64289 Darmstadt Germany Fraunhofer Inst Appl Opt & Precis Engn IOF Albert Einstein Str 7 D-07745 Jena Germany Leibniz Univ Hannover Inst Quantenoptik Welfengarten 1 D-30167 Hannover Germany

Quantum sensing using non-linear interferometers (NLIs) offers the possibility of bicolour imaging, using light that never interacted with the object of interest, and provides a way to achieve phase supersensitivity, i.e. a Heisenberg-type scaling of the phase uncertainty. Such a scaling behaviour is extremely susceptible to noise and only arises at specific phases that define the optimal working point (WP) of the device. While phase-shifting algorithms are to some degree robust against the deleterious effects induced by noise they extract an image by tuning the interferometer phase over a broad range, implying an operation beyond the WP. In our theoretical study, we investigate both the spontaneous and the high-gain regime of operation of an NLI. In fact, in the spontaneous regime using a distillation technique and operating at the WP leads to a qualitatively similar behaviour. In the high-gain regime, however, typical distillation techniques inherently forbid a scaling better than the standard-quantum limit, as a consequence of the photon statistics of squeezed vacuum. In contrast, an operation at the WP still may lead to a sensitivity below shot noise, even in the presence of noise. Therefore, this procedure opens the perspective of bicolour imaging with a better than shot-noise phase uncertainty by working in the vicinity of the WP. Our results transfer quantum imaging distillation in a noisy environment to the high-gain regime with the ultimate goal of harnessing its full potential by combining bicolour imaging and phase supersensitivity.

关键词： quantum imaging quantum metrology supersensitivity squeezing phase-shifting algorithm non-linear interferometer standard quantum limit

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