Publications by authors named "Liangcai Cao"

70 Publications

Speckle-reduced reconstruction of a single-shot hologram by multiple tip-tilt modulations.

Appl Opt 2021 Jun;60(17):5220-5226

Speckle can be attenuated by averaging the reconstructed images of each sub-hologram or being filtered with different filters, at the expense of resolution. We propose a de-speckling method for a single-shot digital hologram while maintaining the resolution. Different tip-tilt phases are demonstrated to cause changes only for the speckle distributions of the reconstructed image. The speckle is attenuated by averaging these intensity images with different speckle distributions. The normalized contrast can be reduced to 0.56 by averaging only 20 different reconstructed images. When the averaged image is processed with block matching and 3D filtering, a further de-speckled image at a normalized contrast of 0.46 can be obtained with highly preserved resolution.
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http://dx.doi.org/10.1364/AO.426329DOI Listing
June 2021

High-speed computer-generated holography using an autoencoder-based deep neural network.

Opt Lett 2021 Jun;46(12):2908-2911

Learning-based computer-generated holography (CGH) provides a rapid hologram generation approach for holographic displays. Supervised training requires a large-scale dataset with target images and corresponding holograms. We propose an autoencoder-based neural network (holoencoder) for phase-only hologram generation. Physical diffraction propagation was incorporated into the autoencoder's decoding part. The holoencoder can automatically learn the latent encodings of phase-only holograms in an unsupervised manner. The proposed holoencoder was able to generate high-fidelity 4K resolution holograms in 0.15 s. The reconstruction results validate the good generalizability of the holoencoder, and the experiments show fewer speckles in the reconstructed image compared with the existing CGH algorithms.
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http://dx.doi.org/10.1364/OL.425485DOI Listing
June 2021

Phase hologram optimization with bandwidth constraint strategy for speckle-free optical reconstruction.

Opt Express 2021 Apr;29(8):11645-11663

An iterative method with bandwidth constraint strategy is proposed to design phase holograms for high-quality speckle-free optical reconstruction. The bandwidth properties of the reconstructed field are analyzed theoretically based on the sampling theory, which helps in properly allocating the sampling resources for efficiently describing the speckles and artifacts in the reconstructed field. Iterative calculation with bandwidth constraint strategy of the reconstructed field and quadratic initial phase can optimize the phase hologram without stagnation problem, which provides effective controls of the reconstructed intensity fluctuations and helps to suppress the speckles and artifacts. Numerical and optical experiments have been performed to validate the proposed method can achieve excellent image fidelity.
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http://dx.doi.org/10.1364/OE.422115DOI Listing
April 2021

Optical Encryption Based on Computer Generated Holograms in Photopolymer.

Polymers (Basel) 2021 Apr 21;13(9). Epub 2021 Apr 21.

Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.

An optical encryption method based on computer generated holograms printing of photopolymer is presented. Fraunhofer diffraction is performed based on the Gerchberg-Saxton algorithm, and a hologram of the Advanced Encryption Standard encrypted Quick Response code is generated to record the ciphertext. The holograms of the key and the three-dimensional image are generated by the angular spectrum diffraction algorithm. The experimental results show that large-size encrypted Quick Response (QR) code and miniature keys can be printed in photopolymers, which has good application prospects in optical encryption. This method has the advantages of high-density storage, high speed, large fault tolerance, and anti-peeping.
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http://dx.doi.org/10.3390/polym13091358DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8122333PMC
April 2021

Complex wavefront sensing based on coherent diffraction imaging using vortex modulation.

Sci Rep 2021 Apr 27;11(1):9019. Epub 2021 Apr 27.

State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing, 100084, China.

Phase retrieval seeks to reconstruct the phase from the measured intensity, which is an ill-posed problem. A phase retrieval problem can be solved with physical constraints by modulating the investigated complex wavefront. Orbital angular momentum has been recently employed as a type of reliable modulation. The topological charge l is robust during propagation when there is atmospheric turbulence. In this work, topological modulation is used to solve the phase retrieval problem. Topological modulation offers an effective dynamic range of intensity constraints for reconstruction. The maximum intensity value of the spectrum is reduced by a factor of 173 under topological modulation when l is 50. The phase is iteratively reconstructed without a priori knowledge. The stagnation problem during the iteration can be avoided using multiple topological modulations.
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http://dx.doi.org/10.1038/s41598-021-88523-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8079371PMC
April 2021

Band-limited double-phase method for enhancing image sharpness in complex modulated computer-generated holograms.

Opt Express 2021 Jan;29(2):2597-2612

Herein, we propose a band-limited double-phase method to improve the quality of reconstructed images encoded by double-phase holograms (DPHs) derived from complex-amplitude light waves. Although the quality of images produced by DPHs was improved compared to that of conventional holographic images, it still suffered from degradation because of the spatial shifting noise generated during the conversion from complex-amplitude holograms to phase-only holograms. The proposed method overcomes this shortcoming by defining a band-limiting function according to the spatial distribution of DPHs in the frequency domain to remove the specific spatial frequency components severely affected by the spatial shifting of DPHs. The sharpness of images reconstructed from band-limited DPHs with appropriate optical filtering showed an improvement of 36.84% in simulations and 51.67% in experiments evaluated by 10-90% intensity variation.
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http://dx.doi.org/10.1364/OE.414299DOI Listing
January 2021

Axial resolution analysis in compressive digital holographic microscopy.

Opt Express 2021 Jan;29(2):1275-1288

Digital holographic microscopy with compressive sensing (CDHM) has successfully achieved tomography and has been applied in many fields. However, the enhancement of axial resolution in CDHM remains to be elucidated. By deducing accurate formulas for the lateral and axial resolutions without paraxial approximation, we quantized the elongation effect of a digital holography (DH) system in this study. Thus, we revealed that the elongation effect, which is affected only by the system's numerical aperture (NA), is an inherent property of DH systems. We present a detailed analysis herein on the physical significance of the coherence parameter, which is the ratio of a system's limit axial resolution to the interlayer spacing more thoroughly than in previous research. Further, we achieved the tomography of a fiber by using a DH system with a 10 × microscope, with CS to eliminate the elongation effect, and experimentally validated our theoretical results. By applying these theoretical guidelines, we distinguished crossed fibers at distances of 36.4 μm and 48.5 μm, respectively, using the same experimental setup. There would be potential applications of this theory in tomography and observation of microscale objects in the areas of biological and fluid.
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http://dx.doi.org/10.1364/OE.411142DOI Listing
January 2021

Digital Holography and 3D Imaging 2020: introduction to the feature issue.

J Opt Soc Am A Opt Image Sci Vis 2021 Feb;38(2):DH1-DH2

This feature issue of JOSA A and Applied Optics is dedicated to the fourteenth OSA Topical Meeting "Digital Holography and 3D Imaging" held 22-26 June 2020 in a virtual meeting. The conference, taking place every year, is a focal point for global technical interchange in the field of digital holography and 3D imaging, providing premier opportunities for people working in the field to present their new advances in research and development. Papers presented at the meeting highlight current research in digital holography and three-dimensional imaging, including interferometry, phase microscopy, phase retrieval, novel holographic processes, 3D and novel holographic displays, integral imaging, computer-generated holograms, compressive holography, 3D holographic display, AR display, full-field tomography, specific image and signal processing, and holography with various light sources, including coherent to incoherent and x-ray to terahertz waves. Techniques of digital holography and of 3D imaging have numerous applications, such as the state-of-the-art technological developments that are currently underway and stimulate further novel applications of digital holography and 3D imaging in biomedicine, deep learning, and scientific and industrial metrologies.
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http://dx.doi.org/10.1364/JOSAA.419210DOI Listing
February 2021

Digital Holography and 3D Imaging 2020: introduction to the feature issue.

Appl Opt 2021 Feb;60(4):DH1-DH2

This feature issue of JOSA A and Applied Optics is dedicated to the fourteenth OSA Topical Meeting "Digital Holography and 3D Imaging" held 22-26 June 2020 in a virtual meeting. The conference, taking place every year, is a focal point for global technical interchange in the field of digital holography and 3D imaging, providing premier opportunities for people working in the field to present their new advances in research and development. Papers presented at the meeting highlight current research in digital holography and three-dimensional imaging, including interferometry, phase microscopy, phase retrieval, novel holographic processes, 3D and novel holographic displays, integral imaging, computer-generated holograms, compressive holography, 3D holographic display, AR display, full-field tomography, specific image and signal processing, and holography with various light sources, including coherent to incoherent and x-ray to terahertz waves. Techniques of digital holography and of 3D imaging have numerous applications, such as the state-of-the-art technological developments that are currently underway and have also stimulated further novel applications of digital holography and 3D imaging in biomedicine, deep learning, and scientific and industrial metrologies.
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http://dx.doi.org/10.1364/AO.419209DOI Listing
February 2021

Frequency-based optimized random phase for computer-generated holographic display.

Appl Opt 2021 Feb;60(4):A145-A154

Random phases with all frequency components lead to excessive diffusions of object waves, resulting in loss of detail in holographic reconstructions. In this study, the effects of random phases with various frequencies on holographic reconstruction results are evaluated. The optimized maximal value of the random phases is analyzed. Utilizing the evaluation results, we propose a frequency-based optimized random phase that reduces the unfavorable effect of the insufficient dynamic range of computer-generated holograms and prevents excessive diffusions by traditional random phases. Utilizing the optimized random phase, which improves the reconstruction quality significantly, we can commendably reconstruct both contours and details.
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http://dx.doi.org/10.1364/AO.404934DOI Listing
February 2021

Influence of sparse constraint functions on compressive holographic tomography.

Appl Opt 2021 Feb;60(4):A111-A119

In this paper, we quantified and analyzed the impact of the norm and total variation (TV) norm sparse constraints on the reconstruction quality under different interlayer spacings, sampling rates, and signal-to-noise ratios. For high-quality holograms, the results of compressive-sensing reconstruction using norm achieved higher quality than those by the TV norm. In contrast, for low-quality holograms, the quality of TV-norm-based reconstruction results was relatively stable and better than that of norm. In addition, we explained why interlayer spacing cannot be smaller and recommend the use of axial resolution of the digital holography system as the interlayer spacing. The conclusions are valuable in the choice of sparse constraints in compressive holographic tomography.
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http://dx.doi.org/10.1364/AO.404341DOI Listing
February 2021

Complex wavefront sensing based on alternative structured phase modulation.

Appl Opt 2021 Feb;60(4):A48-A53

Spatial light modulators (SLMs), which generate varying phase modulation, are widely used in coherent diffraction imaging. Random patterns are uploaded on the SLM to modulate the measured wavefront. However, a random pattern is highly complex and requires a reliable SLM. In addition, the uncorrelated terms generated from the random modulations need to be sufficiently captured using an imaging sensor with a high signal-to-noise ratio (SNR) to avoid stagnation during iterations. We propose an alternative structured phase modulation (ASPM) method. The modulations are composed of orthogonally placed phase bars that introduce uncorrelated modulations. The ASPM modulation can act as the phase grating; in addition, the modulated intensities are concentrated, which can be captured with a high SNR. The complexity of the ASPM patterns is significantly reduced, which is helpful for utilizing the SLM to generate reliable phase modulation.
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http://dx.doi.org/10.1364/AO.405630DOI Listing
February 2021

Optimal quantization for amplitude and phase in computer-generated holography.

Opt Express 2021 Jan;29(1):119-133

Owing to the characteristics of existing spatial light modulators (SLMs), the computer-generated hologram (CGH) with continuous complex-amplitude is conventionally converted to a quantized amplitude-only or phase-only CGH in practical applications. The quantization of CGH significantly affects the holographic reconstruction quality. In this work, we evaluated the influence of the quantization for both amplitude and phase on the quality of holographic reconstructions by traversing method. Furthermore, we considered several critical CGH parameters, including resolution, zero-padding size, reconstruction distance, wavelength, random phase, pixel pitch, bit depth, phase modulation deviation, and filling factor. Based on evaluations, the optimal quantization for both available and future SLM devices is suggested.
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http://dx.doi.org/10.1364/OE.414160DOI Listing
January 2021

DNN-FZA camera: a deep learning approach toward broadband FZA lensless imaging.

Opt Lett 2021 Jan;46(1):130-133

In mask-based lensless imaging, iterative reconstruction methods based on the geometric optics model produce artifacts and are computationally expensive. We present a prototype of a lensless camera that uses a deep neural network (DNN) to realize rapid reconstruction for Fresnel zone aperture (FZA) imaging. A deep back-projection network (DBPN) is connected behind a U-Net providing an error feedback mechanism, which realizes the self-correction of features to recover the image detail. A diffraction model generates the training data under conditions of broadband incoherent imaging. In the reconstructed results, blur caused by diffraction is shown to have been ameliorated, while the computing time is 2 orders of magnitude faster than the traditional iterative image reconstruction algorithms. This strategy could drastically reduce the design and assembly costs of cameras, paving the way for integration of portable sensors and systems.
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http://dx.doi.org/10.1364/OL.411228DOI Listing
January 2021

High-fidelity pixel-super-resolved complex field reconstruction via adaptive smoothing.

Opt Lett 2020 Dec;45(24):6807-6810

Pixel super-resolution (PSR) techniques have been developed to overcome the sampling limit in lensless digital holographic imaging. However, the inherent non-convexity of the PSR phase retrieval problem can potentially degrade reconstruction quality by causing the iterations to tend toward a false local minimum. Furthermore, the ill posedness of the up-sampling procedure renders PSR algorithms highly susceptible to noise. In this Letter, we propose a heuristic PSR algorithm with adaptive smoothing (AS-PSR) to achieve high-fidelity reconstruction. By automatically adjusting the intensity constraints on the estimated field, the algorithm can effectively locate the optimal solution and converge with high reconstruction quality, pushing the resolution toward the diffraction limit. The proposed method is verified experimentally within a coherent modulation phase retrieval framework, achieving a twofold improvement in resolution. The AS-PSR algorithm can be further applied to other phase retrieval methods based on alternating projection.
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http://dx.doi.org/10.1364/OL.409697DOI Listing
December 2020

A complex-amplitude hologram using an ultra-thin dielectric metasurface.

Nanoscale 2020 Dec 27;12(47):24162-24168. Epub 2020 Nov 27.

School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China.

Metasurfaces have been widely studied for the arbitrary manipulation of the amplitude, phase and polarization of a field at the subwavelength scale. Holographic images with a high resolution and a large viewing angle can be reconstructed from phase-only holograms encoded in a metasurface. The quality of a holographic image can be greatly improved by using complex-amplitude holograms. However, realizing a high efficiency metasurface with simultaneous and independent control of the amplitude and phase remains a great challenge. In this work, an ultrathin dielectric metasurface which can modulate the complex amplitude in the transmission mode is proposed for a metasurface hologram. The amplitude is controlled by adjusting the dipoles and quadrupoles by tuning the geometric size. The phase value from 0 to 2π is manipulated based on the Pancharatnam-Berry phase (also called the geometric phase) by rotating the meta-atom. The experimental results show that a three-dimensional image reconstructed from a complex-amplitude hologram presents better quality than that from a phase-only hologram. The proposed metasurface shows great potential for applications that require complex amplitude modulation.
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http://dx.doi.org/10.1039/d0nr06461kDOI Listing
December 2020

Non-iterative phase hologram generation with optimized phase modulation.

Opt Express 2020 Apr;28(8):11380-11392

A non-iterative algorithm is proposed to generate phase holograms with optimized phase modulation. A quadratic initial phase with continuous distributed spectrum is utilized to iteratively optimize the phase modulation in the reconstruction plane, which can be used as an optimized phase distribution for arbitrary target images. The phase hologram can be calculated directly according to the modulated wave field distribution in the reconstruction plane. Fast generation of the phase holograms can be achieved by this non-iterative implementation, and the avoidance of the random phase modulation helps to suppress the speckle noise. Numerical and optical experiments have demonstrated that the proposed method can efficiently generate phase holograms with quality reconstructions.
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http://dx.doi.org/10.1364/OE.391518DOI Listing
April 2020

Single-shot lensless imaging with fresnel zone aperture and incoherent illumination.

Light Sci Appl 2020 7;9:53. Epub 2020 Apr 7.

2Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA.

Lensless imaging eliminates the need for geometric isomorphism between a scene and an image while allowing the construction of compact, lightweight imaging systems. However, a challenging inverse problem remains due to the low reconstructed signal-to-noise ratio. Current implementations require multiple masks or multiple shots to denoise the reconstruction. We propose single-shot lensless imaging with a Fresnel zone aperture and incoherent illumination. By using the Fresnel zone aperture to encode the incoherent rays in wavefront-like form, the captured pattern has the same form as the inline hologram. Since conventional backpropagation reconstruction is troubled by the twin-image problem, we show that the compressive sensing algorithm is effective in removing this twin-image artifact due to the sparsity in natural scenes. The reconstruction with a significantly improved signal-to-noise ratio from a single-shot image promotes a camera architecture that is flat and reliable in its structure and free of the need for strict calibration.
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http://dx.doi.org/10.1038/s41377-020-0289-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7138823PMC
April 2020

Noise suppression for ballistic-photons based on compressive in-line holographic imaging through an inhomogeneous medium.

Opt Express 2020 Mar;28(7):10337-10349

Noise suppression is one of the most important tasks in imaging through inhomogeneous mediums. Here, we proposed a denoising approach based on compressive in-line holography for imaging through an inhomogeneous medium. A reference-beam-free system with a low-cost continuous-wave laser is presented. The suppression against the noise, which is brought by the scattering photons, is presented in simulations using the proposed algorithm. The noise immunity is demonstrated in lensless imaging behind a random phase mask with an optical depth of 1.42 by single exposure, as well as behind a ground glass with an optical depth of 6.38 by multiple exposures.
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http://dx.doi.org/10.1364/OE.385992DOI Listing
March 2020

Self-referenced multiple-beam interferometric method for robust phase calibration of spatial light modulator.

Opt Express 2019 Nov;27(23):34463-34471

Phase-only liquid crystal spatial light modulator has wide ranging applications that require accurate phase retardance. The phase calibration of the spatial light modulator is therefore of vital importance. Available self-referenced calibration methods face the challenges of high time consumption, low efficiency, and low stability against the conditions. A self-referenced multiple-beam interferometric method is proposed to derive the global grayscale-phase response. As is presented theoretically and experimentally, the proposed method reduces the measuring time and improves the calibration efficiency by encoding multiple fringes in a single hologram. Results also show that the method is equally accurate when compared with traditional two-beam interferometric method, whereas providing a greater robustness against measuring errors since the standard deviation is only 56% of that of the traditional method.
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http://dx.doi.org/10.1364/OE.27.034463DOI Listing
November 2019

Improve the quality of holographic image with complex-amplitude metasurface.

Opt Express 2019 Nov;27(23):33700-33708

Complex-amplitude hologram can provide a high-quality image that is free of twin image and zero-order noise. Multi-SLMs methods, single SLM with space-division modulations and super pixel methods were striving to meet the requirements of complex amplitude modulation. In this work, we propose an ultra-thin dielectric metasurface to improve the quality of holographic image by loading complex amplitude hologram. This metasurface controls the amplitude and phase simultaneously and independently in transmission mode. The multipole expansion method is applied to analyze the mechanism. The polarization conversion efficiency can be up to 99% and the diffraction efficiency is 71%. The simulations verify that the quality of holographic image could be greatly improved by a complex-amplitude metasurface.
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http://dx.doi.org/10.1364/OE.27.033700DOI Listing
November 2019

Digital Holography and 3D Imaging: introduction to the joint feature issue in Applied Optics and Journal of the Optical Society of America A.

Appl Opt 2019 Dec;58(34):DH1

The OSA Topical Meeting on Digital Holography and 3D Imaging (DH) was held 20-23 May 2019 in Bordeaux, France. Feature issues based on the DH meeting series have been released by Applied Optics (AO) since 2007. This year, AO and the Journal of the Optical Society of America A (JOSA A) jointly decided to have one such feature issue in each journal. This feature issue includes 46 papers in AO and 9 in JOSA A and covers a large range of topics, reflecting the rapidly expanding techniques and applications of digital holography and 3D imaging. The upcoming DH Conference (DH 2020) will be held from 22 to 26 June in Vancouver, Canada, as part of the OSA Imaging and Applied Optics Congress.
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http://dx.doi.org/10.1364/AO.58.000DH1DOI Listing
December 2019

Digital correlation of computer-generated holograms for 3D face recognition.

Appl Opt 2019 Dec;58(34):G177-G186

Three-dimensional (3D) face recognition has been a crucial task in human biometric verification and identification. A digital correlation method of a computer-generated hologram (CGH) for 3D face recognition is proposed, which encodes 3D data into a 2D hologram for recognition. The 3D face models are preprocessed and compressed to into groups of feature points. The CGH templates corresponding to the 3D feature points are generated by point- and layer-oriented algorithms based on three different numerical algorithms to encode depth values into 2D holograms. A 2D digital correlation is performed between the CGH templates. It is demonstrated that the generated CGHs templates could be effectively classified based on the correlation performance metrics of discrimination ratio, peak-to-correlation plane energy, and peak-to-noise ratio. With the essence of the CGH algorithm being the conversion of 3D data to a 2D hologram, the proposed encoding and decoding method has great advantages in reducing computational efforts and potential applications in 3D face recognition, storage, and display.
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http://dx.doi.org/10.1364/AO.58.00G177DOI Listing
December 2019

Digital Holography and 3D Imaging: introduction to the joint feature issue in Applied Optics and Journal of the Optical Society of America A.

J Opt Soc Am A Opt Image Sci Vis 2019 Dec;36(12):DH1

The OSA Topical Meeting on Digital Holography and 3D Imaging (DH) was held 20-23 May 2019 in Bordeaux, France. Feature issues based on the DH meeting series have been released by Applied Optics (AO) since 2007. This year, AO and the Journal of the Optical Society of America A (JOSA A) jointly decided to have one such feature issue in each journal. This feature issue includes 46 papers in AO and 9 in JOSA A and covers a large range of topics, reflecting the rapidly expanding techniques and applications of digital holography and 3D imaging. The upcoming DH Conference (DH 2020) will be held from 22 to 26 June in Vancouver, Canada, as part of the OSA Imaging and Applied Optics Congress.
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http://dx.doi.org/10.1364/JOSAA.36.000DH1DOI Listing
December 2019

Digital holography free of 2π ambiguity, using coherence modulation.

Opt Lett 2019 Oct;44(19):4626-4629

In this Letter, a quantitative measurement method with an extended axial range in low-coherence light digital holography is presented. Based on the characteristics of the light source, the degree of coherence and phase values are obtained. Because the degree of coherence is modulated with respect to the optical path difference, it can be used to remove the 2π ambiguity of the phase, without the use of numerical or dual-wavelength methods. The mathematical procedures from three phase-shifting holograms are numerically described. From experimental results, the accurate measurements of a sample with high step are presented to confirm the effectiveness.
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http://dx.doi.org/10.1364/OL.44.004626DOI Listing
October 2019

Three-dimensional computer-generated hologram with Fourier domain segmentation.

Opt Express 2019 Apr;27(8):11689-11697

We propose an efficient algorithm for calculating photorealistic three-dimensional (3D) computer-generated hologram with Fourier domain segmentation. The segmentation of the spatial frequency processes the depth information from multiple parallel projections, recombining the wave fields of different viewing directions in the Fourier domain. Segmented angular spectrum with layer based processing is introduced to calculate the partitioned elements, which effectively extends the limited region of conventional angular spectrum. The algorithm can provide accurate depth cues and is compatible with computer graphics rendering techniques to provide quality view-dependent properties. Experiments demonstrate the proposed method can reconstruct photorealistic 3D images with accurate depth information.
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http://dx.doi.org/10.1364/OE.27.011689DOI Listing
April 2019

Digital holographic phase imaging based on phase iteratively enhanced compressive sensing.

Opt Lett 2019 Mar;44(6):1395-1398

Digital holography has been widely applied in quantitative phase imaging (QPI) for monolayer objects within a limited depth. For multilayer imaging, compressive sensing is employed to eliminate defocused images but with missing phase information. A phase iteratively enhanced compressive sensing (PIE-CS) algorithm is proposed to achieve phase imaging and eliminate defocused images simultaneously. Linear filtering is first applied to the off-axis hologram in Fourier domain, and an intermediate reconstructed complex image is obtained. A periodic phase mask is then superimposed on the intermediate reconstructed image to iteratively eliminate the defocused images and recover the object with phase information. The experimental recovery of amplitude and phase of a two-layer sample with as little as 7% random measurement is demonstrated. The average phase error of the PIE-CS algorithm is analyzed, and the results show the feasibility for QPI.
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http://dx.doi.org/10.1364/OL.44.001395DOI Listing
March 2019

Digital holography and 3D imaging: introduction to the Applied Optics and Journal of the Optical Society of America A joint feature issue.

J Opt Soc Am A Opt Image Sci Vis 2019 Feb;36(2):DH1

The OSA Topical Meeting on Digital Holography and 3D Imaging (DH) was held June 25-28, 2018, in Orlando, Florida, USA. Feature issues based on the DH meeting series have been released by Applied Optics (AO) since 2007. This year, AO and the Journal of the Optical Society of America A (JOSA A) jointly decided to have one such feature issue in each journal. This feature issue includes thirty-eight papers in AO and nine in JOSA A, and covers a large range of topics, reflecting the rapidly expanding techniques and applications of digital holography and 3D imaging. The upcoming DH Conference (DH 2019) will be held May 19-23 in Bordeaux, France.
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http://dx.doi.org/10.1364/JOSAA.36.000DH1DOI Listing
February 2019

Digital holography and 3D imaging: introduction to the Applied Optics and Journal of the Optical Society of America A joint feature issue.

Appl Opt 2019 Feb;58(5):DH1

The OSA Topical Meeting on Digital Holography and 3D Imaging (DH) was held June 25-June 28, 2018, in Orlando, Florida, USA. Feature issues based on the DH meeting series have been released by Applied Optics (AO) since 2007. This year, AO and the Journal of the Optical Society of America A (JOSA A) jointly decided to have one such feature issue in each journal. This feature issue includes thirty-eight papers in AO and nine in JOSA A, and covers a large range of topics, reflecting the rapidly expanding techniques and applications of digital holography and 3D imaging. The upcoming DH Conference (DH 2019) will be held May 19-May 23 in Bordeaux, France.
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http://dx.doi.org/10.1364/AO.58.000DH1DOI Listing
February 2019

Progress in virtual reality and augmented reality based on holographic display.

Appl Opt 2019 Feb;58(5):A74-A81

The past, present, and future industry prospects of virtual reality (VR) and augmented reality (AR) are presented. The future of VR/AR technology based on holographic display is predicted by analogy with the VR/AR based on binocular vision display and light field display. The investigations on holographic display that can be used in VR/AR are reviewed. The breakthroughs of holographic display are promising in VR/AR with high resolution. The challenges faced by VR/AR based on holographic display are analyzed.
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http://dx.doi.org/10.1364/AO.58.000A74DOI Listing
February 2019
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