Applied Sciences

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11 pages, 1816 KiB

Open AccessArticle

Systematic Approach for Alignment of Light Field Mirage

by Yoshiharu Momonoi, Koya Yamamoto, Yoshihiro Yokote, Atsushi Sato and Yasuhiro Takaki

Appl. Sci. 2022, 12(23), 12413; https://doi.org/10.3390/app122312413 - 4 Dec 2022

Viewed by 1509

Abstract

We previously proposed techniques to eliminate repeated three-dimensional (3D) images produced by the light field Mirage, which consists of circularly aligned multiple-slanted light field displays. However, we only constructed the lower half of the system to verify the proposed elimination techniques. In this [...] Read more.

We previously proposed techniques to eliminate repeated three-dimensional (3D) images produced by the light field Mirage, which consists of circularly aligned multiple-slanted light field displays. However, we only constructed the lower half of the system to verify the proposed elimination techniques. In this study, we developed an alignment technique for a complete 360-degree display system. The alignment techniques for conventional 360-degree display systems, which use a large number of projectors, greatly depend on electronic calibration, which indispensably causes image quality degradation. We propose a systematic approach for the alignment for the light field Mirage, which causes less image quality degradation by taking advantage of the small number of display devices required for the light field Mirage. The calibration technique for light field displays, the image stitching technique, and the brightness matching technique are consecutively performed, and the generation of 360-degree 3D images is verified. Full article

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

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13 pages, 4805 KiB

Open AccessArticle

Low-Photon Counts Coherent Modulation Imaging via Generalized Alternating Projection Algorithm

by Meng Sun, Tao Liu, George Barbastathis, Yincheng Qi and Fucai Zhang

Appl. Sci. 2022, 12(22), 11436; https://doi.org/10.3390/app122211436 - 11 Nov 2022

Viewed by 1410

Abstract

Phase contrast imaging is advantageous for mitigating radiation damage to samples, such as biological specimens. For imaging at nanometer or atomic resolution, the required flux on samples increases dramatically and can easily exceed the sample damage threshold. Coherent modulation imaging (CMI) can provide [...] Read more.

Phase contrast imaging is advantageous for mitigating radiation damage to samples, such as biological specimens. For imaging at nanometer or atomic resolution, the required flux on samples increases dramatically and can easily exceed the sample damage threshold. Coherent modulation imaging (CMI) can provide quantitative absorption and phase images of samples at diffraction-limited resolution with fast convergence. When used for radiation-sensitive samples, CMI experiments need to be conducted under low illumination flux for high resolution. Here, an algorithmic framework is proposed for CMI involving generalized alternating projection and total variation constraint. A five-to-ten-fold lower photon requirement can be achieved for near-field or far-field experiment dataset. The work would make CMI more applicable to the dynamics study of radiation-sensitive samples. Full article

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

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11 pages, 2878 KiB

Open AccessArticle

Robust Evaluation of Reference Tilt in Digital Holography

by Xianfeng Xu, Hao Wang, Hui Sheng, Weilong Luo and Xinwei Wang

Appl. Sci. 2022, 12(21), 11224; https://doi.org/10.3390/app122111224 - 5 Nov 2022

Cited by 1 | Viewed by 1371

Abstract

A robust approach is designed to evaluate the reference tilt angle (RTA) accurately and efficiently by local Gaussian fitting (LGF) for the distribution of one frequency peak on a spatial spectrum plane (SSP). The novel method proposed can avoid enlarging the data array [...] Read more.

A robust approach is designed to evaluate the reference tilt angle (RTA) accurately and efficiently by local Gaussian fitting (LGF) for the distribution of one frequency peak on a spatial spectrum plane (SSP). The novel method proposed can avoid enlarging the data array on either a hologram or an SSP and then alleviate the computing burden on information processing hardware. Moreover, the RTA precision can be improved by one order of the magnitude in certain ranges, which benefits not only the accurate image recovery in an off-axis digital holography (DH) display but also the thorough removal of the tilt error effect on the image quality in phase-shifting digital holography (PSDH). The error source of the frequency peak position is analyzed theoretically and the principle with detailed steps is described. Several cases of numerical simulations have been carried out to demonstrate the availability and accuracy of this robust RTA evaluation method. Full article

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

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12 pages, 5247 KiB

Open AccessArticle

High Bandwidth-Utilization Digital Holographic Reconstruction Using an Untrained Neural Network

by Zhuoshi Li, Yuanyuan Chen, Jiasong Sun, Yanbo Jin, Qian Shen, Peng Gao, Qian Chen and Chao Zuo

Appl. Sci. 2022, 12(20), 10656; https://doi.org/10.3390/app122010656 - 21 Oct 2022

Cited by 5 | Viewed by 2217

Abstract

Slightly off-axis digital holographic microscopy (DHM) is the extension of digital holography imaging technology toward high-throughput modern optical imaging technology. However, it is difficult for the method based on the conventional linear Fourier domain filtering to solve the imaging artifacts caused by the [...] Read more.

Slightly off-axis digital holographic microscopy (DHM) is the extension of digital holography imaging technology toward high-throughput modern optical imaging technology. However, it is difficult for the method based on the conventional linear Fourier domain filtering to solve the imaging artifacts caused by the spectral aliasing problem. In this article, we propose a novel high-accuracy, artifacts-free, single-frame, digital holographic phase demodulation scheme for low-carrier-frequency holograms, which incorporates the physical model into a conventional deep neural network (DNN) without training beforehand based on a massive dataset. Although the conventional end-to-end deep learning (DL) method can achieve high-accuracy phase recovery directly from a single-frame hologram, the massive datasets and ground truth collection can be prohibitively laborious and time-consuming. Our method recognizes such a low-carrier frequency fringe demodulation process as a nonlinear optimization problem, which can reconstruct the artifact-free phase details gradually from a single-frame hologram. The phase resolution target and simulation experiment results quantitatively demonstrate that the proposed method possesses better artifact suppression and high-resolution imaging capabilities than the physical methods. In addition, the live-cell experiment also indicates the practicality of the technique in biological research. Full article

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

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12 pages, 25351 KiB

Open AccessArticle

Study of Crack Growth of Transparent Materials Subjected to Laser Irradiation by Digital Holography

by Wenjing Zhou, Yuhang Liu, Zhenkai Chen, Yao Chen, Hongbo Zhang, Yingjie Yu and Vivi Tornari

Appl. Sci. 2022, 12(15), 7799; https://doi.org/10.3390/app12157799 - 3 Aug 2022

Cited by 1 | Viewed by 1752

Abstract

The crack growth of transparent materials after laser wavelength irradiation was studied. It is known that laser irradiation is used in many applications for the ablation of undesired material and/or coatings. The impact of laser irradiation on cracks was studied using the digital [...] Read more.

The crack growth of transparent materials after laser wavelength irradiation was studied. It is known that laser irradiation is used in many applications for the ablation of undesired material and/or coatings. The impact of laser irradiation on cracks was studied using the digital holography (DH) technique. Transparent samples were irradiated using near-ultraviolet, visible, near-infrared, and infrared light. The DH system is able to detect cracks and crack growth of the transparent samples irradiated by a range of laser wavelengths. Results also show that light with infrared to near-infrared wavelengths has a great effect on crack growth. High-resolution photomechanical effects of laser irradiation on material expansion or/and generation of defects due to specific wavelengths are also illustrated. The DH system with a multispectral laser has practical applications for laser cleaning of painted artworks. Full article

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

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16 pages, 3217 KiB

Open AccessArticle

Fast 3D Analytical Affine Transformation for Polygon-Based Computer-Generated Holograms

by Houxin Fan, Bing Zhang, Yaping Zhang, Fan Wang, Wenlong Qin, Qingyang Fu and Ting-Chung Poon

Appl. Sci. 2022, 12(14), 6873; https://doi.org/10.3390/app12146873 - 7 Jul 2022

Cited by 11 | Viewed by 1801

Abstract

We present a fast 3D analytical affine transformation (F3DAAT) method to obtain polygon-based computer-generated holograms (CGHs). CGHs consisting of tens of thousands of triangles from 3D objects are obtained by this method. We have attempted a revised method based on previous 3D affine [...] Read more.

We present a fast 3D analytical affine transformation (F3DAAT) method to obtain polygon-based computer-generated holograms (CGHs). CGHs consisting of tens of thousands of triangles from 3D objects are obtained by this method. We have attempted a revised method based on previous 3D affine transformation methods. In order to improve computational efficiency, we have derived and analyzed our proposed affine transformation matrix. We show that we have further increased the computational efficiency compared with previous affine methods. We also have added flat shading to improve the reconstructed image quality. A 3D object from a 3D camera is reconstructed holographically by numerical and optical experiments. Full article

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

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15 pages, 7621 KiB

Open AccessArticle

Full-Parallax Multiview Generation with High-Speed Wide-Angle Dual-Axis Scanning Optics

by Daerak Heo, Sungjin Lim, Gunhee Lee, Geunseop Choi and Joonku Hahn

Appl. Sci. 2022, 12(9), 4615; https://doi.org/10.3390/app12094615 - 4 May 2022

Cited by 1 | Viewed by 1714

Abstract

Three-dimensional displays are receiving considerable attention owing to their ability to deliver realistic content. Particularly, a multiview display with temporal multiplexing offers advantages in terms of fewer restrictions for optical alignment and flexibility in forming view density. However, most of studies realize horizontal [...] Read more.

Three-dimensional displays are receiving considerable attention owing to their ability to deliver realistic content. Particularly, a multiview display with temporal multiplexing offers advantages in terms of fewer restrictions for optical alignment and flexibility in forming view density. However, most of studies realize horizontal parallax-only multiview display. In a horizontal parallax-only multiview display the content is distorted in the vertical direction as the observer changes the viewing distance. It is helpful to understand this phenomenon using the Wigner distribution function (WDF). In this study, we divided the viewing zone (VZ) into the sub-viewing zone and integrated viewing zone according to the number of views of the observer. Specifically, the changes in the contents are experimentally evaluated at different viewing distances to validate our expectation. For the experiment, we implemented a full-parallax multiview display with spherical symmetry and designed a high-speed wide-angle dual-axis scanner. This scanner comprises two single-axis scanners connected by high numerical-aperture scanning optics. The proposed system and WDF analysis of VZ will be helpful to evaluate the characteristics of the multiview system. Full article

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

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10 pages, 3046 KiB

Open AccessArticle

Efficient Computer-Generated Holography Based on Mixed Linear Convolutional Neural Networks

by Xianfeng Xu, Xinwei Wang, Weilong Luo, Hao Wang and Yuting Sun

Appl. Sci. 2022, 12(9), 4177; https://doi.org/10.3390/app12094177 - 21 Apr 2022

Cited by 2 | Viewed by 1730

Abstract

Imaging based on computer-generated holography using traditional methods has the problems of poor quality and long calculation cycles. However, recently, the development of deep learning has provided new ideas for this problem. Here, an efficient computer-generated holography (ECGH) method is proposed for computational [...] Read more.

Imaging based on computer-generated holography using traditional methods has the problems of poor quality and long calculation cycles. However, recently, the development of deep learning has provided new ideas for this problem. Here, an efficient computer-generated holography (ECGH) method is proposed for computational holographic imaging. This method can be used for computational holographic imaging based on mixed linear convolutional neural networks (MLCNN). By introducing fully connected layers in the network, the suggested design is more powerful and efficient at information mining and information exchange. Using the ECGH, the pure phase image required can be obtained after calculating the custom light field. Compared with traditional computed holography based on deep learning, the method used here can reduce the number of network parameters needed for network training by about two-thirds while obtaining a high-quality image in the reconstruction, and the network structure has the potential to solve various image-reconstruction problems. Full article

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

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14 pages, 5971 KiB

Open AccessArticle

Optimal Spatial Coherence of a Light-Emitting Diode in a Digital Holographic Display

by Sungjin Lim, Hosung Jeon, Sunggyun Ahn and Joonku Hahn

Appl. Sci. 2022, 12(9), 4176; https://doi.org/10.3390/app12094176 - 21 Apr 2022

Cited by 7 | Viewed by 2975

Abstract

The coherence of a light source is a vital aspect regarding the image quality of holographic contents. Generally, the coherence of the light source is the reason for speckle noise in a holographic display, which degrades the image quality. To reduce the speckle [...] Read more.

The coherence of a light source is a vital aspect regarding the image quality of holographic contents. Generally, the coherence of the light source is the reason for speckle noise in a holographic display, which degrades the image quality. To reduce the speckle noise, partially coherent light sources such as light-emitting diodes (LED) have been studied. However, if the coherence of the light source is too low, the reconstructed image will blur. Therefore, using a spatial filter to improve the spatial coherence of LEDs has been proposed. In this study, we analyze the effect of the spatial and temporal coherence of the LED light source in a digital holographic display, and the optimal spatial coherence is determined. For this purpose, we devised an optical structure to control the spatial coherence in a holographic display system using a digital micro-mirror device (DMD). Here, the DMD functions as a dynamic spatial filter. By evaluating the change in the holographic image quality according to the spatial filter size, we obtained an optimal spatial filter size of 270 µm in our system. The proposed method is expected to be useful for selecting the optimal coherence of the light source for holographic displays. Full article

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

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10 pages, 8255 KiB

Open AccessArticle

Accurate Image Locating by Hologram Multiplexing in Off-Axis Digital Holography Display

by Xianfeng Xu, Xinwei Wang and Hao Wang

Appl. Sci. 2022, 12(3), 1437; https://doi.org/10.3390/app12031437 - 28 Jan 2022

Cited by 3 | Viewed by 2386

Abstract

An approach is suggested to recover and then locate the original object image in off-axis digital holography by the multiplexing of hologram (OADHM). The recording configuration is designed by introducing one more plane wave in the interference frame to carry the information for [...] Read more.

An approach is suggested to recover and then locate the original object image in off-axis digital holography by the multiplexing of hologram (OADHM). The recording configuration is designed by introducing one more plane wave in the interference frame to carry the information for the tilt angle of the reference wave (TARW), which is crucial for the holography recovery and the accurate locating of the reconstructed image. The intensity distribution in a hologram plane and the corresponding spatial spectrum of two sets holograms in Fourier domain are analyzed theoretically. When the specific spectra that come from the interference of the two plane waves are detected, the TARW can be calculated by the coordinates of them and then the recovered image can be retrieved by spectrum operation and located at the original place. Series numerical simulations and optical experiments have been carried out to demonstrate the availability and efficiency of the proposed design. Full article

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

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9 pages, 2287 KiB

Open AccessArticle

Holographic 3D Display Using Depth Maps Generated by 2D-to-3D Rendering Approach

by Zehao He, Xiaomeng Sui and Liangcai Cao

Appl. Sci. 2021, 11(21), 9889; https://doi.org/10.3390/app11219889 - 22 Oct 2021

Cited by 20 | Viewed by 2917

Abstract

Holographic display has the potential to be utilized in many 3D application scenarios because it provides all the depth cues that human eyes can perceive. However, the shortage of 3D content has limited the application of holographic 3D displays. To enrich 3D content [...] Read more.

Holographic display has the potential to be utilized in many 3D application scenarios because it provides all the depth cues that human eyes can perceive. However, the shortage of 3D content has limited the application of holographic 3D displays. To enrich 3D content for holographic display, a 2D to 3D rendering approach is presented. In this method, 2D images are firstly classified into three categories, including distant view images, perspective view images and close-up images. For each category, the computer-generated depth map (CGDM) is calculated using a corresponding gradient model. The resulting CGDMs are applied in a layer-based holographic algorithm to obtain computer-generated holograms (CGHs). The correctly reconstructed region of the image changes with the reconstruction distance, providing a natural 3D display effect. The realistic 3D effect makes the proposed approach can be applied in many applications, such as education, navigation, and health sciences in the future. Full article

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

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10 pages, 2650 KiB

Open AccessArticle

Performance Estimation of Intensity Accumulation Display by Computer-Generated Holograms

by Jung-Ping Liu, Yu-Chih Lin, Shuming Jiao and Ting-Chung Poon

Appl. Sci. 2021, 11(16), 7729; https://doi.org/10.3390/app11167729 - 22 Aug 2021

Cited by 6 | Viewed by 2079

Abstract

The image generated by binary computer-generated holograms (CGHs) always suffers from serious speckle noise. Thanks to the fast frame rate of the binary spatial light modulator, the speckle can be significantly suppressed by intensity accumulation, i.e., the sequential display of multiple CGHs of [...] Read more.

The image generated by binary computer-generated holograms (CGHs) always suffers from serious speckle noise. Thanks to the fast frame rate of the binary spatial light modulator, the speckle can be significantly suppressed by intensity accumulation, i.e., the sequential display of multiple CGHs of the same scene. If enough randomness is added to the CGHs, the speckle noise can be mostly averaged out. Intuitively, the quality of the reconstructed image should be proportional to the number of intensity accumulation. However, there is no simple method to predict the dependence of the average noise and accumulation number, and we can only know the results after finishing the full computation. In this paper, we propose an empirical formula of the average noise based on the speckle phenomenon in a laser projector. Using this model, we have confirmed that the randomness induced by random phase is equivalent to that induced by random down-sampling for the generation of binary CGHs. In addition, if the computational efficiency is a concern, the CGH calculated with iterations is not recommended for intensity accumulation display. Finally, there is an upper-quality limit of the reconstructed image by intensity accumulation. Thus, a strategy for efficient intensity accumulation is suggested. Full article

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

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11 pages, 3699 KiB

Open AccessArticle

Computer-Generated Hologram Based on Reference Light Multiplexing for Holographic Display

by Dapu Pi and Juan Liu

Appl. Sci. 2021, 11(16), 7199; https://doi.org/10.3390/app11167199 - 4 Aug 2021

Cited by 3 | Viewed by 2269

Abstract

In this article, we propose a reference light wave multiplexing scheme to increase the information capacity of computer-generated holograms. The holograms were generated by different reference light waves and superimposed together as a multiplexed hologram. A modified Gerchberg–Saxton algorithm was used to improve [...] Read more.

In this article, we propose a reference light wave multiplexing scheme to increase the information capacity of computer-generated holograms. The holograms were generated by different reference light waves and superimposed together as a multiplexed hologram. A modified Gerchberg–Saxton algorithm was used to improve image quality, and different images could be reconstructed when the multiplexed hologram was illuminated by corresponding reference light waves. We performed both numerical simulations and optical experiments to demonstrate the feasibility of the proposed scheme. Numerical simulations showed that the proposed method could reconstruct multiple images successfully by a single multiplexed hologram and optical experiments are consistently good with numerical simulations. It is expected that the proposed method has great potential to be widely applied in holographic displays in the future. Full article

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

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12 pages, 13304 KiB

Open AccessArticle

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

by Takayuki Takahashi, Tomoyoshi Shimobaba, Takashi Kakue and Tomoyoshi Ito

Appl. Sci. 2021, 11(14), 6277; https://doi.org/10.3390/app11146277 - 7 Jul 2021

Cited by 15 | Viewed by 2388

Abstract

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 [...] Read more.

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. Full article

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

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12 pages, 6230 KiB

Open AccessArticle

Resolution Enhancement of Spherical Wave-Based Holographic Stereogram with Large Depth Range

by Zi Wang, Guoqiang Lv, Miao Xu, Qibin Feng, Anting Wang and Hai Ming

Appl. Sci. 2021, 11(12), 5595; https://doi.org/10.3390/app11125595 - 17 Jun 2021

Cited by 1 | Viewed by 1803

Abstract

The resolution-priority holographic stereogram uses spherical waves focusing on the central depth plane (CDP) to reconstruct 3D images. The image resolution near the CDP can be easily enhanced by modifying three parameters: the capturing depth, the pixel size of elemental image and the [...] Read more.

The resolution-priority holographic stereogram uses spherical waves focusing on the central depth plane (CDP) to reconstruct 3D images. The image resolution near the CDP can be easily enhanced by modifying three parameters: the capturing depth, the pixel size of elemental image and the focal length of lens array. However, the depth range may decrease as a result. In this paper, the resolution characteristics were analyzed in a geometrical imaging model, and three corresponding methods were proposed: a numerical method was proposed to find the proper capturing depth; a partial aperture filtering technique was proposed after reducing pixel size; the moving array lenslet technique was introduced after increasing focal length and partial aperture filtering. Each method can enhance resolution within the total depth range. Simulation and optical experiments were performed to verify the proposed methods. Full article

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

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Review

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14 pages, 2921 KiB

Open AccessReview

Progress of the Computer-Generated Holography Based on Deep Learning

by Yixin Zhang, Mingkun Zhang, Kexuan Liu, Zehao He and Liangcai Cao

Appl. Sci. 2022, 12(17), 8568; https://doi.org/10.3390/app12178568 - 26 Aug 2022

Cited by 9 | Viewed by 4473

Abstract

With the explosive developments of deep learning, learning–based computer–generated holography (CGH) has become an effective way to achieve real–time and high–quality holographic displays. Plentiful learning–based methods with various deep neural networks (DNNs) have been proposed. In this paper, we focus on the rapid [...] Read more.

With the explosive developments of deep learning, learning–based computer–generated holography (CGH) has become an effective way to achieve real–time and high–quality holographic displays. Plentiful learning–based methods with various deep neural networks (DNNs) have been proposed. In this paper, we focus on the rapid progress of learning–based CGH in recent years. The generation principles and algorithms of CGH are introduced. The DNN structures frequently used in CGH are compared, including U–Net, ResNet, and GAN. We review the developments and discuss the outlook of the learning–based CGH. Full article

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

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15 pages, 8843 KiB

Open AccessReview

Enlargements of Viewing Zone and Screen Size of Holographic Displays Using MEMS SLM Combined with Scanning Systems

by Yasuhiro Takaki

Appl. Sci. 2022, 12(13), 6495; https://doi.org/10.3390/app12136495 - 27 Jun 2022

Cited by 2 | Viewed by 2152

Abstract

The problems of conventional holographic display techniques, which are the requirements of a sub-micron pixel pitch and ultra-high resolution for spatial light modulators (SLMs) to enlarge the viewing zone and screen size, can be addressed using microelectromechanical systems (MEMS) SLMs combined with spatial [...] Read more.

The problems of conventional holographic display techniques, which are the requirements of a sub-micron pixel pitch and ultra-high resolution for spatial light modulators (SLMs) to enlarge the viewing zone and screen size, can be addressed using microelectromechanical systems (MEMS) SLMs combined with spatial scanning systems. Various scanning systems have been efficiently combined with high-speed image generation of MEMS SLMs based on the time-multiplexing technique. The horizontal scanning system enlarged the viewing zone and screen size, the circular scanning system provided 360° three-dimensional (3D) images, and the RGB scanning system generated color 3D images. The screen size can be increased scalably using a multichannel system based on the space-multiplexing technique. The use of a short laser pulse illumination system eliminates the mechanical scanning system and greatly simplifies the display system. The measurements of the accommodation responses of human eyes showed that 3D images generated by the screen scanning holographic display have a possibility to solve the visual fatigue issue caused by the vergence–accommodation conflict, which prevents the long-time usage of conventional 3D displays. Full article

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

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