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Meng Z, Ding L, Feng S, Xing F, Nie S, Ma J, Pedrini G, Yuan C. Numerical dark-field imaging using deep-learning. OPTICS EXPRESS 2020; 28:34266-34278. [PMID: 33182900 DOI: 10.1364/oe.401786] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 10/20/2020] [Indexed: 06/11/2023]
Abstract
Dark-field microscopy is a powerful technique for enhancing the imaging resolution and contrast of small unstained samples. In this study, we report a method based on end-to-end convolutional neural network to reconstruct high-resolution dark-field images from low-resolution bright-field images. The relation between bright- and dark-field which was difficult to deduce theoretically can be obtained by training the corresponding network. The training data, namely the matched bright- and dark-field images of the same object view, are simultaneously obtained by a special designed multiplexed image system. Since the image registration work which is the key step in data preparation is not needed, the manual error can be largely avoided. After training, a high-resolution numerical dark-field image is generated from a conventional bright-field image as the input of this network. We validated the method by the resolution test target and quantitative analysis of the reconstructed numerical dark-field images of biological tissues. The experimental results show that the proposed learning-based method can realize the conversion from bright-field image to dark-field image, so that can efficiently achieve high-resolution numerical dark-field imaging. The proposed network is universal for different kinds of samples. In addition, we also verify that the proposed method has good anti-noise performance and is not affected by the unstable factors caused by experiment setup.
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Bianco V, Memmolo P, Leo M, Montresor S, Distante C, Paturzo M, Picart P, Javidi B, Ferraro P. Strategies for reducing speckle noise in digital holography. LIGHT, SCIENCE & APPLICATIONS 2018; 7:48. [PMID: 30839600 PMCID: PMC6106996 DOI: 10.1038/s41377-018-0050-9] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 06/01/2018] [Accepted: 06/05/2018] [Indexed: 05/05/2023]
Abstract
Digital holography (DH) has emerged as one of the most effective coherent imaging technologies. The technological developments of digital sensors and optical elements have made DH the primary approach in several research fields, from quantitative phase imaging to optical metrology and 3D display technologies, to name a few. Like many other digital imaging techniques, DH must cope with the issue of speckle artifacts, due to the coherent nature of the required light sources. Despite the complexity of the recently proposed de-speckling methods, many have not yet attained the required level of effectiveness. That is, a universal denoising strategy for completely suppressing holographic noise has not yet been established. Thus the removal of speckle noise from holographic images represents a bottleneck for the entire optics and photonics scientific community. This review article provides a broad discussion about the noise issue in DH, with the aim of covering the best-performing noise reduction approaches that have been proposed so far. Quantitative comparisons among these approaches will be presented.
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Affiliation(s)
- Vittorio Bianco
- CNR-ISASI Istituto di Scienze Applicate e Sistemi Intelligenti “E. Caianiello”, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Pasquale Memmolo
- CNR-ISASI Istituto di Scienze Applicate e Sistemi Intelligenti “E. Caianiello”, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Marco Leo
- CNR-ISASI Istituto di Scienze Applicate e Sistemi Intelligenti “E. Caianiello”, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Silvio Montresor
- Université du Maine, CNRS UMR 6613, LAUM, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9, France
| | - Cosimo Distante
- CNR-ISASI Istituto di Scienze Applicate e Sistemi Intelligenti “E. Caianiello”, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Melania Paturzo
- CNR-ISASI Istituto di Scienze Applicate e Sistemi Intelligenti “E. Caianiello”, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Pascal Picart
- Université du Maine, CNRS UMR 6613, LAUM, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9, France
| | - Bahram Javidi
- Electrical and Computer Engineering Department, University of Connecticut, U-4157, Storrs, CT 06269 USA
| | - Pietro Ferraro
- CNR-ISASI Istituto di Scienze Applicate e Sistemi Intelligenti “E. Caianiello”, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
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Zheng J, Gao P, Shao X, Nienhaus GU. Refractive index measurement of suspended cells using opposed-view digital holographic microscopy. APPLIED OPTICS 2017; 56:9000-9005. [PMID: 29131185 DOI: 10.1364/ao.56.009000] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/13/2017] [Indexed: 06/07/2023]
Abstract
Opposed-view digital holographic microscopy (OV-DHM) with autofocusing and out-of-focus background suppression was demonstrated and applied to measure the refractive index (RI) of suspended HeLa cells. In OV-DHM, a specimen is illuminated from two sides in a 4π-like configuration. The generated two opposite-view object waves, which have orthogonal polarization orientations, interfere with a common reference wave, and the generated holograms are recorded by a CMOS camera. The image plane of the sample was determined by finding the minimal variation between the two object waves. The out-of-focus background was suppressed by averaging the two object waves. Simultaneous determination of both the cell thickness and the phase retardation was avoided by using a spheroidal model for the detached cell obtained from confocal microscopy. Thus, the RI of suspended HeLa cells was measured from phase images of OV-DHM, with the thickness of the cells estimated by using a constant axial-to-lateral ratio. This measurement strategy reveals the RI with an accuracy of ∼10% of the RI difference between cells and surrounding medium.
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Opposite-view digital holographic microscopy with autofocusing capability. Sci Rep 2017; 7:4255. [PMID: 28652591 PMCID: PMC5484697 DOI: 10.1038/s41598-017-04568-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 05/16/2017] [Indexed: 11/08/2022] Open
Abstract
Digital holographic microscopy (DHM) has its intrinsic ability to refocusing a sample by numerically propagating an object wave from its hologram plane to its image plane. In this paper opposite-view digital holographic microscopy (OV-DHM) is demonstrated for autofocusing, namely, digitally determining the location of the image plane, and refocusing the object wave without human intervention. In OV-DHM, a specimen is illuminated from two sides in a 4π-alike configuration, and two holograms are generated and recorded by a CCD camera along two orthogonal polarization orientations. The image plane of the sample is determined by finding the minimal variation between the two object waves, and consequently refocusing is performed by propagating the waves to the image plane. Furthermore, the field of view (FOV) of OV-DHM can be extended by combining the two object waves which have an angle in-between. The proposed technique also has the potential to reduce speckle noise and out-of-focus background.
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Osten W, Faridian A, Gao P, Körner K, Naik D, Pedrini G, Singh AK, Takeda M, Wilke M. Recent advances in digital holography [invited]. APPLIED OPTICS 2014; 53:G44-63. [PMID: 25322137 DOI: 10.1364/ao.53.000g44] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 06/05/2014] [Indexed: 05/25/2023]
Abstract
This article presents an overview of recent advances in the field of digital holography, ranging from holographic techniques designed to increase the resolution of microscopic images, holographic imaging using incoherent illumination, phase retrieval with incoherent illumination, imaging of occluded objects, and the holographic recording of depth-extended objects using a frequency-comb laser, to the design of an infrastructure for remote laboratories for digital-holographic microscopy and metrology. The paper refers to current trends in digital holography and explains them using new results that were recently achieved at the Institute for Applied Optics of the University Stuttgart.
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Faridian A, Pedrini G, Osten W. Opposed-view dark-field digital holographic microscopy. BIOMEDICAL OPTICS EXPRESS 2014; 5:728-36. [PMID: 24688809 PMCID: PMC3959838 DOI: 10.1364/boe.5.000728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 01/22/2014] [Accepted: 02/05/2014] [Indexed: 05/05/2023]
Abstract
Scattering and absorption belong to the major problems in imaging the internal layers of a biological specimen. Due to the structural inhomogeneity of the specimen, the distribution of the structures in the upper layers of a given internal structure of interest is different from the lower layers that may result in different interception of scattered light, falling into the angular aperture of the microscope objective, from the object in each imaging view. Therefore, different spatial frequencies of the scattered light can be acquired from different (top and bottom) views. We have arranged an opposed-view dark-field digital holographic microscope (DHM) to collect the scattered light concurrently from both views with the aim to increase the contrast of internal structures and improve the signal-to-noise ratio. Implementing a DHM system gives the possibility to implement digital refocusing process and obtain multilayer images from each side without a depth scan of the object. The method is explained and the results are presented exemplary for a Drosophila embryo.
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Gao P, Pedrini G, Osten W. Phase retrieval with resolution enhancement by using structured illumination. OPTICS LETTERS 2013; 38:5204-5207. [PMID: 24322218 DOI: 10.1364/ol.38.005204] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In this Letter, we present referenceless phase retrieval methods with resolution enhancement. Structured illuminations with different orientations and phase shifts are generated by a spatial light modulator and are used to illuminate the specimen. The generated diffraction patterns are recorded by a CCD camera, and the phase of the wavefront is reconstructed from these patterns.
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