Article
Computer Science, Hardware & Architecture
Zhenxing Dong, Yuye Ling, Chao Xu, Yan Li, Yikai Su
Summary: Deep learning-based computer-generated holography (CGH) has made rapid progress, but the transmission of massive holograms remains a challenge for lightweight wearable near-eye displays. Existing hologram compression methods neglect the human visual system and thus limit compression efficiency. This study proposes an efficient holographic compression framework based on foveated rendering, which reduces pixel numbers by transmitting the high-resolution foveal region at a low compression rate and the low-resolution peripheral region at a high compression rate. The method achieves a compression rate of 40x for a hologram resolution of 1024 x 1024, outperforming the state-of-the-art method and obtaining a PSNR of 28.8 dB for the foveal image.
Article
Physics, Applied
Guan Wang, Huaxia Deng, Mengchao Ma, Xiang Zhong, Xinglong Gong
Summary: Inspired by the human eye retina, foveated single-pixel imaging employs a fast algorithm to reduce time consumption for real-time imaging. The algorithmic transform facilitates the acquisition of foveated reconstructions, mimicking human eye movements and adapting to motion tracking. The proposed method has the advantages of avoiding complex optics design, low time consumption, and wider vision field.
APPLIED PHYSICS LETTERS
(2023)
Article
Computer Science, Software Engineering
Xiaoxu Meng, Ruofei Du, Joseph F. JaJa, Amitabh Varshney
Summary: This article presents an efficient algorithm for visualizing 4D light fields with 3D-kernel foveated rendering (3D-KFR) coupled with eye-tracking, which has the potential to dramatically accelerate the rendering of 4D depth-cued light fields. By extending the foveated rendering technique for 3D meshes, a perceptual model for foveated light fields has been developed, leading to significant speedups in light field rendering on high-resolution microscopic datasets with minimal perceptual loss of detail. This approach is expected to reconcile the conflicting goals of visual fidelity and rendering speed for interactive visualization of light fields.
IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS
(2021)
Article
Computer Science, Software Engineering
Praneeth Chakravarthula, Zhan Zhang, Okan Tursun, Piotr Didyk, Qi Sun, Henry Fuchs
Summary: Computer-generated holographic (CGH) displays have great potential but are hindered by speckle noise, which perceptibly affects image quality. This study introduces a method that reduces perceived speckle noise by integrating foveal and peripheral vision characteristics of the Human Visual System (HVS), demonstrating superior perceptual quality on holographic displays.
IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS
(2021)
Article
Computer Science, Software Engineering
David R. Walton, Rafael Kuffner Dos Anjos, Sebastian Friston, David Swapp, Kaan Aksit, Anthony Steed, Tobias Ritschel
Summary: The study introduces a real-time method to compute ventral metamers for peripheral vision, which offers better quality than existing foveation methods and reduces edge blurring effectively. By using smooth moments of steerable filter responses, a novel statistics type suited for real-time rendering is proposed, eliminating the need for costly optimization processes.
ACM TRANSACTIONS ON GRAPHICS
(2021)
Article
Materials Science, Multidisciplinary
Weitao Song, Xinan Liang, Shiqiang Li, Parikshit Moitra, Xuewu Xu, Emmanuel Lassalle, Yuanjin Zheng, Yongtian Wang, Ramon Paniagua-Dominguez, Arseniy Kuznetsov
Summary: Most commercial near-eye 3D displays currently use traditional stereoscopic approach, which leads to visual confusion and fatigue due to the conflict between vergence and accommodation. To tackle this issue, a proof-of-concept solution based on retinal projection technology has been developed, using a small aperture Huygens' metasurface hologram to generate accommodation-free virtual images. This work demonstrates a compact and wearable near-eye display, weighing approximately 50g, that creates clear accommodation-free images ranging from 0.5 to 2m, overlaid with the real world and viewable directly with the naked eye. The design method introduced for these displays solves the vergence-accommodation conflict using a small aperture Huygens' metasurface hologram.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Computer Science, Interdisciplinary Applications
Miguel A. Lago, Craig K. Abbey, Miguel P. Eckstein
Summary: Model observers have a long history of success in predicting human observer performance in clinically-relevant detection tasks, but the influence of 3D search on human performance interacts with the signal's detectability in the visual periphery. Standard model observers do not predict this interaction, highlighting the need for foveated model observers for image quality evaluation with 3D search.
IEEE TRANSACTIONS ON MEDICAL IMAGING
(2021)
Article
Computer Science, Software Engineering
Xuehuai Shi, Lili Wang, Xiaoheng Wei, Ling-Qi Yan
Summary: This study proposes a foveated photon mapping method for rendering realistic global illumination effects in the foveal region of virtual reality applications. The method generates high-density photons in the foveal region and supports rendering diffuse, specular, glossy, and transparent materials. The approach enhances performance by selectively rendering high-quality images in the foveal region.
IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS
(2021)
Article
Optics
Huan Cui, Jie Cao, Qun Hao, Dong Zhou, Haoyu Zhang, Yingqiang Zhang
Summary: Panoramic ghost imaging (PGI) is a novel method that uses a curved mirror to expand the field of view (FOV) of ghost imaging (GI) to 360 degrees, allowing GI to break through in applications with a wide FOV. However, achieving high-resolution PGI with high efficiency is a challenge due to the large amount of data. Therefore, a foveated panoramic ghost imaging (FPGI) method is proposed to achieve a wide FOV, high resolution, and high efficiency by reducing resolution redundancy and promoting the practical applications of GI with a wide FOV.
Article
Computer Science, Software Engineering
Minseok Chae, Kiseung Bang, Dongheon Yoo, Yoonchan Jeong
Summary: In this paper, a novel method is presented to expand the etendue of near-eye holographic displays by generating a sparse eye-box. The conventional displays suffer from narrow field of view or narrow eye-box due to the limited etendue, but by rearranging the eye-box in a sparse manner, the practical etendue can be extended. This is achieved by utilizing a lens array as an eyepiece lens and optimizing the spatial light modulator's phase profile.
ACM TRANSACTIONS ON GRAPHICS
(2023)
Article
Computer Science, Software Engineering
Florian Friess, Matthias Braun, Valentin Bruder, Steffen Frey, Guido Reina, Thomas Ertl
Summary: This study introduces a system that dynamically adjusts encoding quality to reduce required bandwidth while tracking observers' gaze, enabling collaborative exploration of scientific data sets with high visual detail and low-latency transfer of image data.
IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS
(2021)
Article
Engineering, Electrical & Electronic
Kun Yin, Ziqian He, Yannanqi Li, Shin-Tson Wu
Summary: We present a multi-resolution foveated imaging system for virtual reality, which utilizes polarization multiplexing on a single display panel to increase angular resolution without sacrificing frame rate. By employing a polarization-dependent cholesteric liquid crystal reflector, we achieve a 4.4x higher resolution density while maintaining a compact form factor.
JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY
(2022)
Article
Optics
Jooho Lee, Yong Hyub Won
Summary: A foveated display technology addresses the issue of insufficient angular resolution for near-eye displays, with the need for a beam steering element to track human gaze. Electrowetting prism arrays offer a solution for a light and compact optical system while facing challenges with obstructed views and dispersion in beam steering. By utilizing a doublet structure, the chromatic aberration can be reduced by 70%.
Article
Optics
Siwoo Lee, Seungjae Lee, Dongyeon Kim, Byoungho Lee
Summary: This paper introduces a light field optimization technique to address the issue of varying field of views in multifocal displays, compensating for magnification variations among focal planes to alleviate image distortions and depth perception errors. When applied to a tomographic near-eye display system, the algorithm significantly improves the structural similarity index measure of reconstructed images against ground truth by 20%, especially when maintaining a specific eye relief width.
Article
Materials Science, Multidisciplinary
Rong Wang, Yiqian Liang, Manlin Zhao, Zhihua Chen, Lei Zhou, Lei Wang, Gang Yu, Linlin Liu, Zengqi Xie, Junbiao Peng, Yong Cao
Summary: This study demonstrates that electroplating of electrified electrode microarrays is not limited by boundary effects at sub-micrometer scales, enabling the deposition of high-quality luminescent dyes as films. By utilizing small pixels to weaken boundary effects and ease the overlap of diffusion layers, this technique shows high potential for achieving high-resolution and immersive virtual reality displays.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Zhiyong Yang, En-Lin Hsiang, Yizhou Qian, Shin-Tson Wu
Summary: The performance of a 15.6-inch mLCD and an OLED panel were evaluated and compared. The mLCD exhibited advantages in peak brightness, color volume, and power consumption compared to OLED. The study also adopted a new color measurement method recommended by ICDM and proposed a novel strategy for measuring the point spread function.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Electrical & Electronic
Zhenyi Luo, Yuqiang Ding, Yi Rao, Shin-Tson Wu
Summary: The pancake lens structure offers a compact solution for near-eye displays, but the use of a half mirror results in a significant optical loss. The proposed folded optical structure, using polarization-selective cholesteric liquid crystal reflectors, doubles the efficiency and optical path length to balance the tradeoff between form factor and efficiency. Simulation results match well with experiments. Two display configurations are established to evaluate the imaging performances of the proposed pancake lens structure.
JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY
(2023)
Article
Engineering, Electrical & Electronic
Yizhou Qian, Zhiyong Yang, Yu-Hsin Huang, Kuan-Heng Lin, Shin-Tson Wu
Summary: The RGB nanowire light-emitting diode (LED) structures were optimized using a 3D dipole cloud model to achieve a narrower radiation pattern, reduced angular color shift, and higher optical efficiency. Compared to micro-LEDs, which have externally quantum efficiency depending on mesa size, the RGB nanowire LEDs are more efficient for chip sizes below 20, 80, and 10 μm, respectively. Therefore, nanowire LEDs show promise for augmented reality and virtual reality displays that require high-resolution density and efficient directional light emission.
JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY
(2023)
Article
Engineering, Electrical & Electronic
Yannanqi Li, John Semmen, Qian Yang, Shin-Tson Wu
Summary: A new electrically driven polymer-stabilized polarization volume grating (PVG) has been developed, with the diffraction efficiency modulated by a vertical electric field. By doping a small amount of liquid crystal monomer into the host cholesteric liquid crystal, a stabilized polymer network is formed, allowing for reversible unwinding. The fabricated device exhibits submillisecond response time, a large range of diffraction efficiency modulation, and clear see-through capability. Demonstrations of potential applications show suppressed rainbow effect, enhanced light efficiency, and expanded field of view for a waveguide-based augmented reality display. The unique properties and benefits of switchable PVGs could revolutionize near-eye display research, particularly in novel optical systems for augmented reality waveguide displays.
JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY
(2023)
Article
Engineering, Electrical & Electronic
En-Lin Hsiang, Zhiyong Yang, Shin-Tson Wu
Summary: Virtual reality (VR) devices use imaging optics to magnify microdisplay images, providing an immersive viewing experience. Microdisplays need high-resolution density and dynamic range to meet human vision system requirements. However, increasing resolution and dynamic range can reduce optical efficiency and complicate microdisplay panel fabrication. This paper analyzes image degradation in VR devices caused by both imaging optics and microdisplay, finding that imaging optics significantly impact microdisplay requirements, such as contrast ratio, local dimming zones, and resolution density. These findings help prevent excessive microdisplay design in pancake lens-based VR headsets.
JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY
(2023)
Article
Engineering, Electrical & Electronic
Yuqiang Ding, Yannanqi Li, Qian Yang, Shin-Tson Wu
Summary: This paper proposes a single full-color waveguide AR display based on reflective polarization volume gratings (PVGs) to improve stability and wearing comfort. By analyzing the optical system, we optimize a three-layer PVG as an in-coupler and derive the field of view limit. With a single-layer, thin PVG as an out-coupler, we achieve a relatively uniform exit pupil of 8 mm at the horizontal pupil expansion direction.
JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY
(2023)
Editorial Material
Optics
En-Lin Hsiang, Shin-Tson Wu
Summary: Compared to conventional bulky spectropolarimeters, computational spectropolarimeters reconstruct light-field information in a compact form factor, enabling new applications. A tunable liquid crystal metasurface can modulate the phase and spectral information of light, paving the way for developing compact and low-cost spectropolarimetric imaging devices with widespread applications.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Zhiyong Yang, Yizhou Qian, Junyu Zou, Chia-Lun Lee, Chih-Lung Lin, Shin-Tson Wu
Summary: To achieve high resolution and low power consumption in virtual reality applications, field sequential color (FSC) is used to triple the resolution density and optical efficiency of LCDs. By evaluating the physical properties of a high birefringence nematic LC mixture, a fringe-field switching (FFS) LCD was designed to exhibit fast response time for FSC operation. The FSC LCD also demonstrated wide color gamut and superior color uniformity.
APPLIED SCIENCES-BASEL
(2023)
Article
Optics
Zhenyi Luo, Yannanqi Li, John Semmen, Yi Rao, Shin-Tson Wu
Summary: This study demonstrates an achromatic diffractive liquid-crystal device to overcome the chromatic aberration issue. The proposed device consists of three stacked diffractive liquid crystal optical elements with specific spectral response and polarization selectivity. Simulation and experimental results show significant improvement in imaging performance. This technology has potential applications in virtual reality and mixed reality fields.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Crystallography
Yizhou Qian, Zhiyong Yang, En-Lin Hsiang, Qian Yang, Kevin Nilsen, Yu-Hsin Huang, Kuan-Heng Lin, Shin-Tson Wu
Summary: Vehicle displays are becoming increasingly integrated into our daily lives, requiring high-resolution density and sufficient brightness to combat intense ambient light. Infotainment displays demand over 800 nit brightness to display images clearly under direct sunlight, while head-up displays need to strike a delicate balance between resolution density, brightness, transparency, and image quality.
Article
Optics
Chien-Chung Lin, Yuh-Renn Wu, Hao-Chung Kuo, Matthew S. Wong, Steven P. Denbaars, Shuji Nakamura, Ayush Pandey, Zetian Mi, Pengfei Tian, Kazuhiro Ohkawa, Daisuke Iida, Tao Wang, Yuefei Cai, Jie Bai, Zhiyong Yang, Yizhou Qian, Shin-Tson Wu, Jung Han, Chen Chen, Zhaojun Liu, Byung-Ryool Hyun, Jae-Hyun Kim, Bongkyun Jang, Hyeon-Don Kim, Hak-Joo Lee, Ying-Tsang Liu, Yu-Hung Lai, Yun-Li Li, Wanqing Meng, Haoliang Shen, Bin Liu, Xinran Wang, Kai-ling Liang, Cheng-Jhih Luo, Yen-Hsiang Fang
Summary: Micro light-emitting diode (micro-LED) is expected to play a significant role in future smart displays, offering advantages in various applications. The article focuses on the current status, challenges, and potential advances in micro-LED technology, highlighting the importance of epitaxy innovation and quantum scale structures. Peripheral components and technologies, such as microchip transfer and repair, heterogeneous integration, and novel 2D materials, are also discussed. The potential of micro-LED displays in augmented reality (AR) and the efforts to address existing problems are emphasized.
JOURNAL OF PHYSICS-PHOTONICS
(2023)
Article
Optics
Jianghao Xiong, Haizheng Zhong, Dewen Cheng, Shin-Tson Wu, Yongtian Wang
Summary: This study demonstrates a polarization hologram with full DoF for local manipulation of optical structure, based on emerging self-assembled photo-aligned liquid crystal technology. The ability to record arbitrary wavefront and perform local liquid crystal adjustment is achieved through freeform surface exposure and inkjet printing, respectively, resulting in a full-color retinal scanning display without color crosstalk.
Review
Optics
Yuqian Ding, Qian Yang, Yannanqi Li, Zhiyong Yang, Zhengyang Wang, Haowen Liang, Shin-Tson Wu
Summary: This review paper focuses on the perspectives and challenges of optical waveguide combiners for augmented reality (AR) displays. It introduces the basic device structures and operation principles of different AR architectures, and delves into different waveguide combiners, including geometric and diffractive waveguide combiners. Commonly used in-couplers and out-couplers are discussed, and their properties are analyzed in detail. The paper also explores recent advances in waveguide combiner design and modeling, and discusses the bottlenecks and future development trends in waveguide combiner technologies.
Article
Crystallography
Yuge Huang, Shin-Tson Wu
Summary: The Mini-LED backlit LCD exhibits premium display performance, including motion blur reduction, high dynamic range, and suppression of the halo effect.
LIQUID CRYSTALS TODAY
(2023)
Article
Materials Science, Multidisciplinary
Junyu Zou, Lingshan Li, Shin-Tson Wu
Summary: Maxwellian-view structure has several advantages in augmented reality (AR) displays, including high efficiency, always-in-focus, and a simple optical structure. However, its small eyebox has been a bottleneck. Many efforts have been made to enlarge the eyebox, but the importance of gaze matching has been neglected. This study demonstrates a gaze-matching Maxwellian-view AR system with an enlarged eyebox.
ADVANCED PHOTONICS RESEARCH
(2022)