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

Chen, Lizhi; Tian, Songzhi; Zhang, Hao; Cao, Liangcai; Jin, Guofan

doi:10.1364/oe.422115

Cited by 44 publications

(25 citation statements)

References 38 publications

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“…However, this method works well for amplitude holograms, but needs improvements for phase-only and binary holograms [14,15]. Optimization of CGH using the Gerchberg-Saxton algorithm [16,17] and the gradient descent method [18] obtains a reconstructed image with good image quality, however, it is computationally expensive due to iterative calculations. This paper proposes a time-division holographic projection projected on a large screen.…”

Section: Methodsmentioning

confidence: 99%

Time-Division Color Holographic Projection in Large Size Using a Digital Micromirror Device

et al. 2021

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Holographic projection is a simple projection as it enlarges or reduces reconstructed images without using a zoom lens. However, one major problem associated with this projection is the deterioration of image quality as the reconstructed image enlarges. In this paper, we propose a time-division holographic projection, in which the original image is divided into blocks and the holograms of each block are calculated. Using a digital micromirror device (DMD), the holograms were projected at high speed to obtain the entire reconstructed image. However, the holograms on the DMD need to be binarized, thereby causing uneven brightness between the divided blocks. We correct this by controlling the displaying time of each hologram. Additionally, combining both the proposed and noise reduction methods, the image quality of the reconstructed image was improved. Results from the simulation and optical reconstructions show we obtained a full-color reconstruction image with reduced noise and uneven brightness.

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Section: Methodsmentioning

confidence: 99%

Time-Division Color Holographic Projection in Large Size Using a Digital Micromirror Device

et al. 2021

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“…There are two relationships between the above four planes, namely diffraction (hologram plane and intermediate plane) and conjugate imaging (intermediate plane, reconstruction plane and retina plane). In other holographic near-eye displays, the "diffraction" may be Fourier transform 22 , or others. Here, we take "diffraction" as an example to analyze…”

Section: Four-plane Sampling Modelmentioning

confidence: 99%

Phase space analysis of sampling in the diffraction fields for holographic near-eye displays

Xiao

Zhang

2022

Holography, Diffractive Optics, and Applications XII

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Holographic near-eye display (H-NED) is one of the most promising technologies in three-dimensional (3D) augmented reality and virtual reality displays due to its ability to provide all depth cues. The numerical calculation of diffraction fields is the basis and key step in the design flow of H-NEDs, and the sampling is the core. In this study, from the perspective of phase space optics, a systematical analysis on the sampling of the wavefield and intensity in H-NEDs is presented. The space-bandwidth product evolution of the wavefield and intensity are given via Wigner distribution function. The sampling criteria, minimum number of samples and conservation law of nonuniform sampling points of the intensity are provided. Such a comprehensive sampling analysis provides guidelines for the correct numerical calculation of diffraction fields in H-NEDs.

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“…In terms of suppressing speckle noise, improvements can be made in the initial phase setting, with non-random phases such as the quadratic phase and the conical phase used as the initial value of the phase iteration in some studies [20,21]. To avoid the speckle noise caused by the random initial phase, in 2021 Chen et al proposed an initial phase with bandwidth constraint, which ensures the bandwidth constraint of the reproduced optical field and distributes the whole signal energy as evenly as possible to the hologram region [22]. Pang et al proposed to use the quadratic phase as the initial phase, and was able to determine the relevant parameters of the quadratic phase according to the imaging and geometric relationships of the lens, thus significantly improving the scattering noise, but there are optical artifacts in the reconstructed image [23].…”

Section: Introductionmentioning

confidence: 99%

A Hybrid Iterative Algorithm of Amplitude Weighting and Phase Gradient Descent for Generating Phase-Only Fourier Hologram

Min¹,

Yang²,

Du³

et al. 2022

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Reconstruction of target images from phase-only hologram (POH) has the advantages of high diffraction efficiency and no conjugate terms. The Gerchberg-Saxton (GS) algorithm is a classical algorithm applied to recover the phase, but it most likely stagnantes after a few iterations. This paper proposes a hybrid iterative algorithm of Amplitude Weighting and Phase Gradient Descent (AW-PGD) to generate a higher-quality POH. Firstly, the quadratic phase is used as the initial phase, zero-pads the periphery of the target image, and then multiplies the two to form the complex amplitude as the iterative initial value. During iteration, the amplitude of the reconstructed image is constrained by an adaptive dynamic exponential term in the signal region to improve the reconstruction accuracy, the constraint in the non-signal region is relaxed to reduce the computational effort at the same time; and the phase gradient descent technology is used to increase the iteration step and speed up the convergence. Finally, the target image amplitude is reconstructed based on the generated POH. The numerical simulation results show that the algorithm does not have a significant increase in time cost with better reconstruction quality than the GS, Weighted GS (WGS) and Adaptive Weighted GS (AWGS) algorithm.

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

Cited by 44 publications

References 38 publications

Time-Division Color Holographic Projection in Large Size Using a Digital Micromirror Device

Time-Division Color Holographic Projection in Large Size Using a Digital Micromirror Device

Phase space analysis of sampling in the diffraction fields for holographic near-eye displays

A Hybrid Iterative Algorithm of Amplitude Weighting and Phase Gradient Descent for Generating Phase-Only Fourier Hologram

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