Holography has immense potential for near-eye displays in virtual and augmented reality (VR/AR), providing natural 3D depth cues through wavefront reconstruction. However, balancing the field of view (FOV) with the eyebox remains challenging, constrained by the étendue limitation. Additionally, holographic image quality is often compromised due to differences between actual wave propagation and simulation models. This study addresses these by expanding the eyebox via multi-angle illumination, and enhancing image quality with end-to-end pupil-aware hologram optimization. Further, energy efficiency is improved by incorporating higher-order diffractions and pupil constraints. We explore a Pupil-HOGD algorithm for multi-angle illumination and validate it with a dual-angle holographic display prototype. Integrated with camera calibration and tracked eye position, the developed Pupil-HOGD algorithm improves image quality and expands the eyebox by 50% horizontally. We envision this approach extends the space-bandwidth product (SBP) of holographic displays, enabling broader applications in immersive, high-quality visual computing.

An optical-see-through near-eye display (NED) for augmented reality (AR) allows the user to perceive virtual and real imagery simultaneously. Existing technologies for optical-see-through AR NEDs involve trade-offs between key metrics such as field of view (FOV), eyebox size, form factor, etc. We have enhanced an existing compact wide-FOV pinlight AR NED design with real-time 3D pupil localization in order to dynamically steer and thus effectively enlarge the usable eyebox. This is achieved with a dual-camera rig that captures stereoscopic views of the pupils. The 3D pupil location is used to dynamically calculate a display pattern that spatio-temporally modulates the light entering the wearer's eyes. We have built a demonstrable compact prototype and have conducted a user study that indicates the effectiveness of our eyebox steering method (e.g., without eyebox steering, in 10.5% of our tests, users were unable to perceive the test pattern correctly before experiment timeout; with eyebox steering, that fraction decreased dramatically to 1.25%). This is a small yet crucial step in making simple wide-FOV pinlight NEDs usable for human users and not just as demonstration prototypes filmed with a precisely positioned camera standing in for the user's eye. Further contributions of this paper include a detailed description of display design, calibration technique, and user study design, all of which may benefit other NED research.

Autostereoscopic displays allow the users to view the 3D content on electronic displays without wearing any glasses. However, the content for glass-free 3D displays needs to be in 3D format such that novel views could be synthesized. Unfortunately, nowadays images/videos are still normally captured in 2D which cannot be directly utilized for glass-free 3D displays. In this paper, we introduce an AI-empowered cloud solution towards end-to-end 2D-to-3D image conversion for autostereoscopic 3D displays, or “CONVAS (3D)” in short. Taking a single 2D image as the input, CONVAS (3D) is able to automatically convert the input 2D image and generate an image suitable for a target autostereoscopic 3D display. It is implemented on a web-based server such that it can allow the users to submit the conversion task and to retrieve the results without geographical constraints.

Holography is perhaps the only method demonstrated so far that can achieve a wide field of view (FOV) and a compact eyeglass-style form factor for augmented reality (AR) near-eye displays (NEDs). Unfortunately, the eyebox of such NEDs is impractically small (~ <; 1mm). In this paper, we introduce and demonstrate a design for holographic NEDs with a practical, wide eyebox of ~ 10mm and without any moving parts, based on holographic lenslets. In our design, a holographic optical element (HOE) based on a lenslet array was fabricated as the image combiner with expanded eyebox. A phase spatial light modulator (SLM) alters the phase of the incident laser light projected onto the HOE combiner such that the virtual image can be perceived at different focus distances, which can reduce the vergence-accommodation conflict (VAC). We have successfully implemented a bench-top prototype following the proposed design. The experimental results show effective eyebox expansion to a size of ~ 10mm. With further work, we hope that these design concepts can be incorporated into eyeglass-size NEDs.

Virtual Reality (VR) technologies have advanced fast and have been applied to a wide spectrum of sectors in the past few years. VR can provide an immersive experience to users by generating virtual images and displaying the virtual images to the user with a head-mounted display (HMD) which is a primary component of VR. Normally, an HMD contains a list of hardware components, e.g., housing pack, micro LCD display, microcontroller, optical lens, etc. Settings of VR HMD to accommodate the user's inter-pupil distance (IPD) and the user's eye focus power are important for the user's experience with VR. Although various methods have been developed towards IPD and focus adjustments for VR HMD, the increased cost and complexity impede the possibility for users who wish to assemble their own VR HMD for various purposes, e.g., DIY teaching, etc. In our paper, we present a novel design towards building a customizable and adjustable HMD for VR in a cost-effective manner. Modular design methodology is adopted, and the VR HMD can be easily printed with 3D printers. The design also features adjustable IPD and variable distance between the optical lens and the display. It can help to mitigate the vergence and accommodation conflict issue. A prototype of the customizable and adjustable VR HMD has been successfully built up with off-the-shelf components. A VR software program running on Raspberry Pi board has been developed and can be utilized to show the VR effects. A user study with 20 participants is conducted with positive feedback on our novel design. Modular design can be successfully applied for building up VR HMD with 3D printing. It helps to promote the wide application of VR at affordable costs while featuring flexibility and adjustability.

In this paper, we present our novel design for switchable AR/VR near-eye displays which can help solve the vergence-accommodation-conflict issue. The principal idea is to time-multiplex virtual imagery and real-world imagery and use a tunable lens to adjust focus for the virtual display and the see-through scene separately. With this novel design, prescription eyeglasses for near- and far-sighted users become unnecessary. This is achieved by integrating the wearer's corrective optical prescription into the tunable lens for both virtual display and see-through environment. We built a prototype based on the design, comprised of micro-display, optical systems, a tunable lens, and active shutters. The experimental results confirm that the proposed near-eye display design can switch between AR and VR and can provide correct accommodation for both.

A novel and efficient 3D calibration method for different types of autostereoscopic multi-view 3D displays is presented in this paper. In our method, a camera is placed at different locations within the viewing volume of a 3D display to capture a series of images that relate to the subset of light rays emitted by the 3D display and arriving at each of the camera positions. Gray code patterns modulate the images shown on the 3D display, helping to significantly reduce the number of images captured by the camera and thereby accelerate the process of calculating the correspondence relationship between the pixels on the 3D display and the locations of the capturing camera. The proposed calibration method has been successfully tested on two different types of multi-view 3D displays and can be easily generalized for calibrating other types of such displays. The experimental results show that this novel 3D calibration method can also be used to improve the image quality by reducing the frequently observed crosstalk that typically exists when multiple users are simultaneously viewing multi-view 3D displays from a range of viewing positions.