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33 pages, 9768 KB

Open AccessReview

Recent Advances in Spatially Incoherent Coded Aperture Imaging Technologies

by Vipin Tiwari, Shivasubramanian Gopinath, Tauno Kahro, Francis Gracy Arockiaraj, Agnes Pristy Ignatius Xavier, Narmada Joshi, Kaupo Kukli, Aile Tamm, Saulius Juodkazis, Joseph Rosen and Vijayakumar Anand

Technologies 2025, 13(5), 210; https://doi.org/10.3390/technologies13050210 - 21 May 2025

Cited by 5 | Viewed by 3622

Abstract

Coded aperture imaging (CAI) is a powerful imaging technology that has rapidly developed during the past decade. CAI technology and its integration with incoherent holography have led to the development of several cutting-edge imaging tools, devices, and techniques with widespread interdisciplinary applications, such [...] Read more.

Coded aperture imaging (CAI) is a powerful imaging technology that has rapidly developed during the past decade. CAI technology and its integration with incoherent holography have led to the development of several cutting-edge imaging tools, devices, and techniques with widespread interdisciplinary applications, such as in astronomy, biomedical sciences, and computational imaging. In this review, we provide a comprehensive overview of the recently developed CAI techniques in the framework of incoherent digital holography. The review starts with an overview of the milestones in modern CAI technology, such as interferenceless coded aperture correlation holography, followed by a detailed survey of recently developed CAI techniques and system designs in subsequent sections. Each section provides a general description, principles, potential applications, and associated challenges. We believe that this review will act as a reference point for further advancements in CAI technologies. Full article

(This article belongs to the Collection Review Papers Collection for Advanced Technologies)

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15 pages, 10080 KB

Open AccessTutorial

Spatial Ensemble Mapping for Coded Aperture Imaging—A Tutorial

by Narmada Joshi, Agnes Pristy Ignatius Xavier, Shivasubramanian Gopinath, Vipin Tiwari and Vijayakumar Anand

Photonics 2024, 11(12), 1174; https://doi.org/10.3390/photonics11121174 - 13 Dec 2024

Cited by 2 | Viewed by 2098

Abstract

Coded aperture imaging (CAI) is a well-established computational imaging technique consisting of two steps, namely the optical recording of an object using a coded mask, followed by a computational reconstruction using a computational algorithm using a pre-recorded point spread function (PSF). In this [...] Read more.

Coded aperture imaging (CAI) is a well-established computational imaging technique consisting of two steps, namely the optical recording of an object using a coded mask, followed by a computational reconstruction using a computational algorithm using a pre-recorded point spread function (PSF). In this tutorial, we introduce a simple yet elegant technique called spatial ensemble mapping (SEM) for CAI that allows us to tune the axial resolution post-recording from a single camera shot recorded using an image sensor. The theory, simulation studies, and proof-of-concept experimental studies of SEM-CAI are presented. We believe that the developed approach will benefit microscopy, holography, and smartphone imaging systems. Full article

(This article belongs to the Special Issue Optical Imaging Innovations and Applications)

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21 pages, 56300 KB

Open AccessEditor’s ChoiceReview

Optical Imaging Using Coded Aperture Correlation Holography (COACH) with PSF of Spatial-Structured Longitudinal Light Beams—A Study Review

by Joseph Rosen and Vijayakumar Anand

Photonics 2024, 11(2), 115; https://doi.org/10.3390/photonics11020115 - 26 Jan 2024

Cited by 12 | Viewed by 3565

Abstract

Spatial-structured longitudinal light beams are optical fields sculpted in three-dimensional (3D) space by diffractive optical elements. These beams have been recently suggested for use in improving several imaging capabilities, such as 3D imaging, enhancing image resolution, engineering the depth of field, and sectioning [...] Read more.

Spatial-structured longitudinal light beams are optical fields sculpted in three-dimensional (3D) space by diffractive optical elements. These beams have been recently suggested for use in improving several imaging capabilities, such as 3D imaging, enhancing image resolution, engineering the depth of field, and sectioning 3D scenes. All these imaging tasks are performed using coded aperture correlation holography systems. Each system designed for a specific application is characterized by a point spread function of a different spatial-structured longitudinal light beam. This article reviews the topic of applying certain structured light beams for optical imaging. Full article

(This article belongs to the Special Issue Structured Light Beams: Science and Applications)

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8 pages, 327 KB

Open AccessProceeding Paper

Advanced Imaging Methods Using Coded Aperture Digital Holography

by Joseph Rosen

Eng. Proc. 2023, 34(1), 2; https://doi.org/10.3390/HMAM2-14122 - 6 Mar 2023

Cited by 4 | Viewed by 2003

Abstract

Optical imaging has been utilized in nature and technology for decades. Recently, new methods of optical imaging assisted by computational imaging techniques have been proposed and demonstrated. We describe several new methods of three-dimensional optical imaging, from Fresnel incoherent correlation holography (FINCH) to [...] Read more.

Optical imaging has been utilized in nature and technology for decades. Recently, new methods of optical imaging assisted by computational imaging techniques have been proposed and demonstrated. We describe several new methods of three-dimensional optical imaging, from Fresnel incoherent correlation holography (FINCH) to interferenceless coded aperture correlation holography (COACH). FINCH and COACH are methods for recording digital holograms of a three-dimensional scene. However, COACH can be used for other incoherent and coherent optical applications. The possible applications for these imaging methods, ranging from a new generation of fluorescence microscopes to noninvasive imaging methods through a scattering medium, are mentioned. Full article

(This article belongs to the Proceedings of International Conference on “Holography Meets Advanced Manufacturing”)

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14 pages, 9926 KB

Open AccessArticle

Enhancement of Imaging Quality of Interferenceless Coded Aperture Correlation Holography Based on Physics-Informed Deep Learning

by Rui Xiong, Xiangchao Zhang, Xinyang Ma, Lili Qi, Leheng Li and Xiangqian Jiang

Photonics 2022, 9(12), 967; https://doi.org/10.3390/photonics9120967 - 11 Dec 2022

Cited by 7 | Viewed by 2729

Abstract

Interferenceless coded aperture correlation holography (I-COACH) was recently introduced for recording incoherent holograms without two-wave interference. In I-COACH, the light radiated from an object is modulated by a pseudo-randomly-coded phase mask and recorded as a hologram by a digital camera without interfering with [...] Read more.

Interferenceless coded aperture correlation holography (I-COACH) was recently introduced for recording incoherent holograms without two-wave interference. In I-COACH, the light radiated from an object is modulated by a pseudo-randomly-coded phase mask and recorded as a hologram by a digital camera without interfering with any other beams. The image reconstruction is conducted by correlating the object hologram with the point spread hologram. However, the image reconstructed by the conventional correlation algorithm suffers from serious background noise, which leads to poor imaging quality. In this work, via an effective combination of the speckle correlation and neural network, we propose a high-quality reconstruction strategy based on physics-informed deep learning. Specifically, this method takes the autocorrelation of the speckle image as the input of the network, and switches from establishing a direct mapping between the object and the image into a mapping between the autocorrelations of the two. This method improves the interpretability of neural networks through prior physics knowledge, thereby remedying the data dependence and computational cost. In addition, once a final model is obtained, the image reconstruction can be completed by one camera exposure. Experimental results demonstrate that the background noise can be effectively suppressed, and the resolution of the reconstructed images can be enhanced by three times. Full article

(This article belongs to the Special Issue Advances and Application of Imaging on Digital Holography)

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17 pages, 13983 KB

Open AccessReview

Nonlinear Reconstruction of Images from Patterns Generated by Deterministic or Random Optical Masks—Concepts and Review of Research

by Daniel Smith, Shivasubramanian Gopinath, Francis Gracy Arockiaraj, Andra Naresh Kumar Reddy, Vinoth Balasubramani, Ravi Kumar, Nitin Dubey, Soon Hock Ng, Tomas Katkus, Shakina Jothi Selva, Dhanalakshmi Renganathan, Manueldoss Beaula Ruby Kamalam, Aravind Simon John Francis Rajeswary, Srinivasan Navaneethakrishnan, Stephen Rajkumar Inbanathan, Sandhra-Mirella Valdma, Periyasamy Angamuthu Praveen, Jayavel Amudhavel, Manoj Kumar, Rashid A. Ganeev, Pierre J. Magistretti, Christian Depeursinge, Saulius Juodkazis, Joseph Rosen and Vijayakumar Anand Show full author list Hide full author list

J. Imaging 2022, 8(6), 174; https://doi.org/10.3390/jimaging8060174 - 20 Jun 2022

Cited by 19 | Viewed by 5689

Abstract

Indirect-imaging methods involve at least two steps, namely optical recording and computational reconstruction. The optical-recording process uses an optical modulator that transforms the light from the object into a typical intensity distribution. This distribution is numerically processed to reconstruct the object’s image corresponding [...] Read more.

Indirect-imaging methods involve at least two steps, namely optical recording and computational reconstruction. The optical-recording process uses an optical modulator that transforms the light from the object into a typical intensity distribution. This distribution is numerically processed to reconstruct the object’s image corresponding to different spatial and spectral dimensions. There have been numerous optical-modulation functions and reconstruction methods developed in the past few years for different applications. In most cases, a compatible pair of the optical-modulation function and reconstruction method gives optimal performance. A new reconstruction method, termed nonlinear reconstruction (NLR), was developed in 2017 to reconstruct the object image in the case of optical-scattering modulators. Over the years, it has been revealed that the NLR can reconstruct an object’s image modulated by an axicons, bifocal lenses and even exotic spiral diffractive elements, which generate deterministic optical fields. Apparently, NLR seems to be a universal reconstruction method for indirect imaging. In this review, the performance of NLR isinvestigated for many deterministic and stochastic optical fields. Simulation and experimental results for different cases are presented and discussed. Full article

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5 pages, 1479 KB

Open AccessProceeding Paper

Enhanced Reconstruction of Spatially Incoherent Digital Holograms Using Synthetic Point Spread Holograms

by Vijayakumar Anand, Joseph Rosen, Soon Hock Ng, Tomas Katkus, Denver P. Linklater, Elena P. Ivanova and Saulius Juodkazis

Eng. Proc. 2021, 11(1), 37; https://doi.org/10.3390/ASEC2021-11162 - 15 Oct 2021

Viewed by 1561

Abstract

Coded aperture imaging (CAI) methods offer multidimensional and multispectral imaging capabilities with minimal resources than what is needed in a lens-based direct imager. In the CAI method, the light diffracted from an object is modulated by a coded mask, and the resulting intensity [...] Read more.

Coded aperture imaging (CAI) methods offer multidimensional and multispectral imaging capabilities with minimal resources than what is needed in a lens-based direct imager. In the CAI method, the light diffracted from an object is modulated by a coded mask, and the resulting intensity distribution is recorded. Most of the CAI techniques involve two steps: the recording of the point spread function (PSF) and object intensity under identical conditions and with the same coded mask. The image of the object is reconstructed by computationally processing the PSF and object intensity. The above recording and reconstruction procedure precludes the introduction of special beam characteristics in imaging, such as a direct imager. In this study, a postprocessing approach is developed, where synthetic PSFs capable of introducing special beam characteristics when processed with the object intensity are generated using an iterative algorithm. The method is applied to generate edge-enhanced images in both CAI as well as Fresnel incoherent correlation holography methods. Full article

(This article belongs to the Proceedings of The 2nd International Electronic Conference on Applied Sciences)

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11 pages, 7167 KB

Open AccessArticle

Edge and Contrast Enhancement Using Spatially Incoherent Correlation Holography Techniques

by Vijayakumar Anand, Joseph Rosen, Soon Hock Ng, Tomas Katkus, Denver P Linklater, Elena P Ivanova and Saulius Juodkazis

Photonics 2021, 8(6), 224; https://doi.org/10.3390/photonics8060224 - 16 Jun 2021

Cited by 18 | Viewed by 4456

Abstract

Image enhancement techniques (such as edge and contrast enhancement) are essential for many imaging applications. In incoherent holography techniques such as Fresnel incoherent correlation holography (FINCH), the light from an object is split into two, each of which is modulated differently from one [...] Read more.

Image enhancement techniques (such as edge and contrast enhancement) are essential for many imaging applications. In incoherent holography techniques such as Fresnel incoherent correlation holography (FINCH), the light from an object is split into two, each of which is modulated differently from one another by two different quadratic phase functions and coherently interfered to generate the hologram. The hologram can be reconstructed via a numerical backpropagation. The edge enhancement procedure in FINCH requires the modulation of one of the beams by a spiral phase element and, upon reconstruction, edge-enhanced images are obtained. An optical technique for edge enhancement in coded aperture imaging (CAI) techniques that does not involve two-beam interference has not been established yet. In this study, we propose and demonstrate an iterative algorithm that can yield from the experimentally recorded point spread function (PSF), a synthetic PSF that can generate edge-enhanced reconstructions when processed with the object hologram. The edge-enhanced reconstructions are subtracted from the original reconstructions to obtain contrast enhancement. The technique has been demonstrated on FINCH and CAI methods with different spectral conditions. Full article

(This article belongs to the Special Issue Holography)

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Graphical abstract

25 pages, 69505 KB

Open AccessFeature PaperReview

Review of 3D Imaging by Coded Aperture Correlation Holography (COACH)

by Joseph Rosen, Vijayakumar Anand, Mani Ratnam Rai, Saswata Mukherjee and Angika Bulbul

Appl. Sci. 2019, 9(3), 605; https://doi.org/10.3390/app9030605 - 12 Feb 2019

Cited by 31 | Viewed by 7985

Abstract

Coded aperture correlation holography (COACH) is a relatively new technique to record holograms of incoherently illuminated scenes. In this review, we survey the main milestones in the COACH topic from two main points of view. First, we review the prime architectures of optical [...] Read more.

Coded aperture correlation holography (COACH) is a relatively new technique to record holograms of incoherently illuminated scenes. In this review, we survey the main milestones in the COACH topic from two main points of view. First, we review the prime architectures of optical hologram recorders in the family of COACH systems. Second, we discuss some of the key applications of these recorders in the field of imaging in general, and for 3D super-resolution imaging, partial aperture imaging, and seeing through scattering medium, in particular. We summarize this overview with a general perspective on this research topic and its prospective directions. Full article

(This article belongs to the Special Issue Holography, 3D Imaging and 3D Display)

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