Comparison of state-of-the-art Computer Generated Holography algorithms and a machine learning approach

Author(s):

Madsen, Andreas Erik Gejl; Eriksen, René Lynge & Glückstad, Jesper

Abstract:

“This work studies the use of machine learning and, in particular, a Convolutional Neural Network (CNN) to generate digital holograms and how such a network compares to state-of-the-art iterative methods, both in terms of reconstruction quality and computation time. Since CNNs only require a single pass through the network by a target image to generate a result, and not tens or hundreds of expensive iterations as in the iterative methods, they may be able to accomplish real-time hologram generation; an ability that could open the technology to proper commercial use.

In this work, a CNN built on the UNet architecture, capable of hologram generation, is presented. The network is trained on 4096 images of varying spatial frequencies, both user-generated and from the DIV2K dataset. It is compared to the most common iterative method for hologram generation, namely the Gerchberg–Saxton(GS) algorithm and its modern and improved implementations. In reconstruction quality, the neural network outperforms the original implementation of GS when evaluating Mean Square Error (MSE), geometric error (GE), Structural Similarity Index Measurement (SSIM), and Peak Signal-Noise Ratio (PSNR) of 64 unseen test images. However, on the same test images, the network lacks behind the modern, optimized GS implementations in all error and accuracy measurements. The network does, however, achieve these results at a rate 70–280 times faster than the iterative methods, depending on the particular implementation of the GS algorithm, which corresponds to a possible generation rate of the network of 32 FPS on average.”

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Publication: Optics Communications
Issue/Year: Optics Communications, Pages 127590; 2021
DOI: 10.1016/j.optcom.2021.127590

Fast calculation of computer generated hologram based on single Fourier transform for holographic three-dimensional display

Author(s):

Chang, Chenliang; Zhu, Dongchen; Li, Jiamao; Wang, Di; Xia, Jun & Zhang, Xiaolin

Abstract:

“We present an efficient method for the fast calculation of computer generated hologram (CGH). The 3D object is split into sub-layers according to its depth information. A 2D all-in-focus image is generated by sequential tiling all the layers in one plane. A Fourier hologram that contains all the information of 3D object is calculated from the fast Fourier transform (FFT) of the reassembled 2D image. By multiplying a pre-calculated multifocal off-axis digital phase mask (DPM) to the Fourier hologram, the content of each layer is axially relocated to different depth in the Fourier transform optical system to reconstruct the 3D object. The computation speed of the proposed method is greatly improved with only single FFT calculation process. Both of simulation and experimental results proves the validation of the proposed method.”

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Publication: Displays
Issue/Year: Displays, Volume 69; Pages 102064; 2021
DOI: 10.1016/j.displa.2021.102064

Holographic near-eye display based on complex amplitude modulation with band-limited zone plates

Author(s):

Chen, Yun; Hua, Minjie; Zhang, Tianshun; Zhou, Mingxin; Wu, Jianhong & Zou, Wenlong

Abstract:

“A holographic near-eye display (NED) system based on complex amplitude modulation (CAM) with band-limited zone plates is proposed. The whole system mainly consists of a phase-only spatial light modulator (SLM), an Abbe-Porter filter system, an eyepiece, and an image combiner. The point source method based on band limited zone plates is used to accurately control the bandwidth of the target complex amplitude. The effects of intensity modulation coefficient γ in the frequency-filtering method on the intensity and the quality of reconstructed images are analyzed, which provide a judgment basis for selecting the appropriate value of γ. We also derive the expressions of the field of view (FOV) and exit pupil of the NED system. Since the holographic image is magnified in two steps in this system, the large FOV can be obtained. The optical experimental results show that the proposed system can provide a dynamic holographic three-dimensional (3D) augmented reality (AR) display with a 23.5°horizontal FOV.”

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Publication: Optics Express
Issue/Year: Optics Express, Volume 29; Number 14; Pages 22749; 2021
DOI: 10.1364/oe.431032

Vision-correcting Holographic Display: Evaluation of Aberration Correcting Hologram

Author(s):

Kim, Dongyeon; Nam, Seung-Woo; Bang, Kiseung; Lee, Byounghyo; Lee, Seungjae; Jeong, Youngmo; Seo, Jongmo & Lee, Byoungho

Abstract:

“Vision-correcting displays are key to achieving physical and physiological comforts to the users with refractive errors. Among such displays are holographic displays, which can provide a high-resolution vision-adaptive solution with complex wavefront modulation. However, none of the existing hologram rendering techniques have considered the optical properties of the human eye nor evaluated the significance of vision correction. Here, we introduce vision-correcting holographic display and hologram acquisition that integrates user-dependent prescriptions and a physical model of the optics, enabling the correction of on-axis and off-axis aberrations. Experimental and empirical evaluations of the vision-correcting holographic displays show the competence of holographic corrections over the conventional vision correction solutions.”

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Publication: Biomedical Optics Express
Issue/Year: Biomedical Optics Express,Vol. 12, Issue 8, pp. 5179-5195, 2021
DOI: 10.1364/boe.433919

Fourier horizontal parallax only computer and digital holography of large size

Author(s):

Kozacki, Tomasz; Martinez-Carranza, Juan; kuko{l}owicz, Rafa{l} & Chlipa{l}a, Maksymilian

Abstract:

“Registration and reconstruction of high-quality digital holograms with a large view angle are intensive computer tasks since they require the space-bandwidth product (SBP) of the order of tens of gigapixels or more. This massive use of SBP severely affects the storing and manipulation of digital holograms. In order to reduce the computer burden, this work focuses on the generation and reconstruction of very large horizontal parallax only digital holograms (HPO-DHs). It is shown that these types of holograms can preserve high quality and large view angle in x direction while keeping a low use of SBP. This work first proposes a numerical technique that allows calculating very large HPO-DHs with large pixel size by merging the Fourier holography and phase added stereogram algorithm. The generated Fourier HPO-DHs enable accurate storing of holographic data from 3D objects. To decode the information contained in these Fourier HPO-DHs (FHPO-DHs), a novel angular spectrum (AS) technique that provides an efficient use of the SBP for reconstruction is proposed. Our reconstruction technique, which is called compact space bandwidth AS (CSW-AS), makes use of cylindrical parabolic waves that solve sampling issues of FHPO-DHs and AS. Moreover, the CSW-AS allows for implementing zero-padding for accurate wavefield reconstructions. Hence, suppression of aliased components and high spatial resolution is possible. Notably, the imaging chain of Fourier HPO-DH enables efficient calculation, reconstruction and storing of HPO holograms of large size. Finally, the accuracy and utility of the developed technique is proved by both numerical and optical reconstructions.”

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Publication: Optics Express
Issue/Year: Optics Express, Volume 29; Number 12; Pages 18173; 2021
DOI: 10.1364/oe.421186

Aberration-free digital holographic phase imaging using the derivative-based principal component analysis

Author(s):

Lai, Xiaomin; Xiao, Sheng; Xu, Chen; Fan, Shanhui & Wei, Kaihua

Abstract:

“Significance: Digital holographic microscopy is widely used to get the quantitative phase information of transparent cells.

Aim: However, the sample phase is superimposed with aberrations. To quantify the phase information, aberrations need to be fully compensated.

Approach: We propose a technique to obtain aberration-free phase imaging, using the derivative-based principal component analysis (dPCA).

Results: With dPCA, almost all aberrations can be extracted and compensated without requirements on background segmentation, making it efficient and convenient.

Conclusions: It solves the problem that the conventional principal component analysis (PCA) algorithm cannot compensate the common but intricate higher order cross-term aberrations, such as astigmatism and coma. Moreover, the dPCA strategy proposed here is not only suitable for aberration compensation but also applicable for other cases where there exist cross-terms that cannot be analyzed with the PCA algorithm.”

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Publication: Journal of Biomedical Optics
Issue/Year: Journal of Biomedical Optics, Volume 26; Number 04; 2021
DOI: 10.1117/1.jbo.26.4.046501

SLM Simulation and MonteCarlo Path Tracing for Computer-Generated Holograms

Author(s):

Magallón, Juan; Blesa, Alfonso & Serón, Francisco

Abstract:

“Computer holography is a growing research field that must pay attention to two main issues concerning computing effort: the visualization of a 3D virtual scene with photo-realistic quality and the bottleneck related to hologram digitizalition and visualization limits. This work shows a computational approach based on a Monte Carlo path-tracing algorithm, which accounts for both geometrical and physical phenomena involved in hologram generation, and, therefore, makes a feasible estimation of computing time costs. As these holograms also require yet unavailable visualization devices, their behavior needs to be simulated by computer techniques.”

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Publication: SN Computer Science
Issue/Year: SN Computer Science, Volume 2; Number 3; 2021
DOI: 10.1007/s42979-021-00632-6

Twin curvilinear vortex beams

Author(s):

Wang, Zhuang; Yuan, Zheng; Gao, Yuan; Yan, Wenxiang; Liang, Chunjuan; Ren, Zhi-Cheng; Wang, Xi-Lin; Ding, Jianping & Wang, Hui-Tian

Abstract:

“We report on a novel curvilinear optical vortex beam named twin curvilinear vortex beams (TCVBs) with intensity and phase distribution along a pair of two- or three-dimensional curves, both of which share the same shape and the same topological charge. The TCVBs also possess the character of perfect optical vortex, namely having a size independent of topological charge. We theoretically demonstrate that a TCVB rather than a single-curve vortex beam can be created by the Fourier transform of a cylindrically polarized beam. The behavior of TCVBs generated through our method is investigated by simulation and experiment, including interference experiments for identifying the vortex property of the TCVBs. The TCVBs may find applications in optical tweezers, such as trapping low refractive index particles in the dark region between two curves and driving them moving along the curvilinear trajectory.”

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Publication: Optics Express
Issue/Year: Optics Express, Volume 29; Number 9; Pages 14112; 2021
DOI: 10.1364/oe.423803

Holographic contact lens display that provides focusable images for eyes

Author(s):

Sano, Junpei & Takaki, Yasuhiro

Abstract:

“In this paper, we propose a holographic image generation technique for contact lens displays. The proposed technique employs a phase-only spatial light modulator (SLM), a holographic optical element (HOE) backlight, and a polarizer. The proposed holographic technique can generate 3D images apart from the contact lens displays. Therefore, the eyes can focus on the 3D images while simultaneously observing the real scene through the phase-only SLM and the HOE backlight, which provides see-through capability. A bench-top experimental system was constructed to verify the far-distance image generation capability and see-through function.”

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Publication: Optics Express
Issue/Year: Optics Express, Volume 29; Number 7; Pages 10568; 2021
DOI: 10.1364/oe.419604

GAN-Holo: Generative Adversarial Networks-Based Generated Holography Using Deep Learning

Author(s):

Khan, Aamir; Zhijiang, Zhang; Yu, Yingjie; Khan, Muhammad Amir; Yan, Ketao & Aziz, Khizar

Abstract:

“Current development in a deep neural network (DNN) has given an opportunity to a novel framework for the reconstruction of a holographic image and a phase recovery method with real-time performance. There are many deep learning-based techniques that have been proposed for the holographic image reconstruction, but these deep learning-based methods can still lack in performance, time complexity, accuracy, and real-time performance. Due to iterative calculation, the generation of a CGH requires a long computation time. A novel deep generative adversarial network holography (GAN-Holo) framework is proposed for hologram reconstruction. This novel framework consists of two phases. In phase one, we used the Fresnel-based method to make the dataset. In the second phase, we trained the raw input image and holographic label image data from phase one acquired images. Our method has the capability of the noniterative process of computer-generated holograms (CGHs). The experimental results have demonstrated that the proposed method outperforms the existing methods.”

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Publication: Complexity
Issue/Year: Complexity, Volume 2021; Pages 1-7; 2021
DOI: 10.1155/2021/6662161
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