Adaptive piston correction of sparse aperture systems with stochastic parallel gradient descent algorithm

Xie, Zongliang; Ma, Haotong; He, Xiufeng; Qi, Bo; Ren, Guanghui; Dong, Li; Tan, Yufeng

doi:10.1364/oe.26.009541

Cited by 27 publications

(6 citation statements)

References 21 publications

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“…Examples include the Large Binocular Telescope 4 , the Large Magellan Telescope (GMT) 5 , and the Very Large Telescope 6 . These systems have evolved into essential tools for modern astronomical observations [7][8][9] . The RRSA imaging system has the advantages of lower cost and ease of use, and it offers greater research potential and value compared to traditional circular aperture systems.…”

Section: Related Work 21 Optical Synthetic Aperture Technologymentioning

confidence: 99%

Image restoration using dual-domain fusion network for rotating rectangular synthetic aperture system

deng,

Zhang,

et al. 2024

Sixth Conference on Frontiers in Optical Imaging and Technology: Novel Imaging Systems

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Compared to single aperture systems, optical synthetic aperture systems greatly improve the spatial resolution, yet still exhibit a certain degree of blurring and contrast reduction. To address this challenge, numerous image restoration methods have been proposed. Recently, instead of the conventional circular synthetic aperture, the rotating rectangular synthetic aperture (RRSA) system employs a rectangular aperture to capture a sequence of images of the same scene. The RRSA system’s foldable design and absence of common-phase adjustments confer cost and complexity benefits. The captured degraded image sequences contain information about multiple directions of the target scene, so it is necessary to use multi-frame image fusion technology to restore them. However, most conventional methods often introduce visual artifacts and require substantial computational time. In this paper, we propose a Dual-Domain Fusion Network (DDFNet), restoring multi-frame degraded images in the spatial and frequency domain and then achieving superior fusion results. DDFNet employs a nested U-Net architecture to capture local pixel-level relationships, facilitating the recovery of local features and structures from spatial domain images. In parallel, we transform the input images into the frequency domain, and utilize another nested U-Net for feature extraction on the normalized spectrum and phase, thereby improving the recovery of texture and edge information. Finally, the fusion model effectively utilizes multi-level features and contextual awareness to combine the spatial and frequency domain features, achieving high-quality fusion results of captured degraded sequence images. Extensive experiments demonstrate that our method achieves superior performance both in quantitative and qualitative assessments compared to state-of-the-art techniques.

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Section: Related Work 21 Optical Synthetic Aperture Technologymentioning

confidence: 99%

Image restoration using dual-domain fusion network for rotating rectangular synthetic aperture system

deng,

Zhang,

et al. 2024

Sixth Conference on Frontiers in Optical Imaging and Technology: Novel Imaging Systems

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“…Before an extended object is observed, first, optical sparse aperture systems can be phased with a point source. It would be difficult to correct the systems using the methods mentioned above when pistons will again inevitably appear because of turbulence during the observation of the extended object [19]. The PD method, which is typically based on focused and slightly defocused images, removes all ambiguities and allows piston reconstruction regardless of the size of the object observed [20,21].…”

Section: Introductionmentioning

confidence: 99%

Piston Detection of Optical Sparse Aperture Systems Based on an Improved Phase Diversity Method

Zhao,

Li,

Liu

et al. 2023

Photonics

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The piston error has a significant effect on the imaging resolution of the optical sparse aperture system. In this paper, an improved phase diversity method based on particle swarm optimization and the sequential quadratic programming algorithm is proposed, which can overcome the drawbacks of the traditional phase diversity method and particle swarm optimization, such as the instability that results from polychromatic light conditions and premature convergence. The method introduces factor β in the stage of calculating the objective function, and combines the advantages of a heuristic algorithm and a nonlinear programming algorithm in the optimization stage, thus enhancing the accuracy and stability of piston detection. Simulations based on a dual-aperture optical sparse aperture system verified that the root mean square error obtained by the method can be guaranteed to be within 0.001λ (wavelength), which satisfies the requirement of practical imaging. An experimental test was also conducted to demonstrate the performance of the method, and the test results showed that the quality of the image after piston detection and correction improved significantly compared to images with the co-phase error.

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“…In 2019, this group applied speckle imaging technology to the SAT, resulting in high-resolution reconstructed images [ 7 ]. In 2017, the Institute of Optics and Electronics of the Chinese Academy of Sciences (CAS) created a three sub-aperture synthetic imaging telescope based on phase detection; in this system, each sub-aperture is 127 mm [ 8 , 9 ]. In 2020, the segmented large-scale of lightweight diffractive telescope, whose primary mirror is made up of eight sub-mirrors and has a 352-mm aperture, was constructed by the same Institute [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

Demonstration of a Fizeau Directly-Imaging Sparse-Aperture Telescope with Pointing and Tracking Capabilities

et al. 2023

Self Cite

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At present, the majority of sparse-aperture telescopes (SATs) are unable to observe moving targets. In this paper, we describe the construction of and present the results obtained using a Fizeau directly-imaging sparse-aperture telescope (FDISAT) that permits pointing and the tracking of moving targets. The telescope comprises three sub-apertures, each of which is equipped with a Risley prism system that permits a maximum tracking range of 5° and has independent boresight adjustment capability. On targets in various positions, experiments with pointing and tracking are conducted. The maximum root-mean-square error (RMSE) of pointing in the sub-apertures was found to be 8.22 arcsec. When considering a target moving at 0.01°/s for approximately 320 s, the maximum RMSE of tracking in the sub-apertures was found to be 4.23 arcsec. The images obtained from the focal plane detector exhibit clear interference fringes while tracking. The experimental results demonstrate that the system can effectively track moving targets, providing a method for SAT observation of moving targets.

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Adaptive piston correction of sparse aperture systems with stochastic parallel gradient descent algorithm

Cited by 27 publications

References 21 publications

Image restoration using dual-domain fusion network for rotating rectangular synthetic aperture system

Image restoration using dual-domain fusion network for rotating rectangular synthetic aperture system

Piston Detection of Optical Sparse Aperture Systems Based on an Improved Phase Diversity Method

Demonstration of a Fizeau Directly-Imaging Sparse-Aperture Telescope with Pointing and Tracking Capabilities

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