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See‐through near‐eye displays, such as head‐mounted displays and augmented reality glasses, integrate physical environment with virtual digital contents to form a cohesive world that combines both realities. Field‐of‐view (FOV) is a critical parameter determines the optical performance of these displays. Here we evaluate the see‐through FOV of an optical see‐through near eye display. The evaluation is based on the standardized Michelson contrast method, which provides a unified metric for the measurement of see‐through FOV in near‐eye displays. [ABSTRACT FROM AUTHOR]

See‐through eyewear displays provide immersive augmented reality experiences by superimposing virtual contents over the view of real‐world scenes. Advancements in AR technologies have led to increasingly complicated design of see‐through eyewear displays (EWDs), presenting challenges to the measurement of their optical parameters and performances. Here we review the challenges and the progress in standardizing such measurements. The latest standard IEC 63145‐22‐20 is discussed, which defines industry benchmarks for evaluating the eyewear displays. [ABSTRACT FROM AUTHOR]

Large screen LED displays are becoming increasingly popular. The human eye has a resolution of 1/60 degree, so at very close viewing the LED chips may be more easily seen because LED screens have a larger pixel pitch than traditional display technologies, unlike OLEDs and LCDs. In large LED displays, the perceived luminance of the pixels is highly dependent on the viewing distance and FOV. The paper examines the perceived pixel luminance of a large screen LED display at different viewing distances and field of views. Additionally, stray light was examined and discussed. The results indicated that the perceived pixel luminance can be significantly different under different viewing distances and FOVs. For future LED display performance evaluation, it would be advantageous to have a measuring device with high resolution that mimics the human eye's angular resolution in perceived pixel luminance. [ABSTRACT FROM AUTHOR]

The location of the entrance pupil, field of view, and motion of the viewer's eye is frequently discussed for virtual reality/augmented reality (VR/AR) displays. In order to properly measure optical performance of these displays, the light measuring device (LMD) must simulate the characteristics of the human eye. An important factor to consider is the location of the entrance pupil (aperture stop setting) of the LMD. We compared field of view (FOV) and luminance deviations with various pupil entrance locations at the LMD in this paper. As a result of the experiment, the entrance pupil at the front focal point of the LMD was the best choice. [ABSTRACT FROM AUTHOR]

Eyewear displays have been gradually adopted in entertainment, industrial, and medical applications. The optical performance and image quality of the eyewear displays are required to be precisely evaluated and quantified. This challenges the conventional light measuring devices since the displays are viewed in an immersed environment and at a much closer viewing distance from the display to the eye. In eyewear display, measurement within the eye box and the LMD to mimic the eyeball movement is the first step to ensure an accurate measurement. This paper explained the difference of eyeball location in LMD measurement. The comparison between the eye pupil center and eyeball rotation center which are currently included in the IEC 63145 series standards is discussed. We experimented with the setups in the measurement system and set eye rotation at the pupil and at the eyeball center for contrast ratio and Michelson contrast. The experimental results were discussed to understand the differences between eye pupil center rotation and eyeball center rotation. [ABSTRACT FROM AUTHOR]

The large screens used in stadiums, shopping malls, and movie theaters typically have multiple viewers looking at them simultaneously. The quantification of these displays' image quality would require more considerations of measurements at different locations to satisfy the multiviewing condition. In this paper, we describe the practical implementation method involved in the current standardization activities. Additionally, a vantage point measurement method is studied. In the actual use case scenarios, the vantage point method is more appropriate. This method mimics the viewing behavior of audiences. The displays we measured were laser projection and LED. The method shows validity in both displays. Using the vantage point method, the experimental data show that the existing large displays may have very prominent differences in luminance and chromaticity at different viewing locations. [ABSTRACT FROM AUTHOR]

The conventional display measurements are no longer satisfying the need for eyewear displays. The measurement of VR/AR type display requires light measuring devices (LMDs) to simulate the characteristics of the human eye. Factors like the position of the pupil, field of view, and the motion of the eye are often discussed. One of the factors to be considered is the choice of entrance pupil location (aperture stop setting) of the LMD. In this paper, a preliminary study was carried out to compare the deviations of FOV and luminance with the choice of entrance pupil location. The experiment demonstrated that it exists as the most accurate eye‐viewing when the entrance pupil is located at the front focal point. [ABSTRACT FROM AUTHOR]

The laser display system consists of a laser projector and a screen, and its image quality depends not only on the output image of the projector. Still, it is also closely related to the screen's performance and the installation geometries, including distance, projection ratio, inclination angle, etc. Recently, IEC TC110 Electronic Displays has published the international standard of Measuring Methods of Image Quality for Laser Projection Displays (IEC 62906‐5‐3:2021). This IS contains the requirements of measuring environmental conditions, optical measuring equipment, installation and alignment of the screen, test patterns, measurement point locations, and procedures. This paper will introduce the practical implementation methods of the measurement methods involved in the standard. At the same time, the measurement method based on audience viewpoints is studied, so the measurement is more in line with the actual laser display applications. The results of both methods were compared, especially for the Fresnel lens screen. [ABSTRACT FROM AUTHOR]

In virtual reality devices, positioning virtual information onto the real‐world scene accurately has always been a challenge. Such performance feature has been widely requiring high precision in vehicle HUD navigation, AR surgery, industrial production assembly and maintenance, and so on. For applications such as surgical use and assembly in the industry, positioning accuracy is essential to evaluate and measure. The accuracy of virtual image positioning depends on the imaging lens, the combiner optics, eye position, etc., and showing the individual parameters of each component is often not adequate to demonstrate the actual performance of the product. As such, the measurement that simulates the human eye under actual product use conditions is crucial for achieving accurate measurement. In this paper, we use a high‐angular resolution 2D imaging luminance meter that mimics the optics of the human eye, together with a two‐axis goniometer, to achieve precise measurement of positioning accuracy. This paper further analyzes the positioning accuracy based on the measurements around both the eye pupil center and eyeball rotation center. In addition, the effects of the applications of the positioning uncertainty were studied. [ABSTRACT FROM AUTHOR]

RNA G-quadruplex (rG4) structure and its association with rG4-binding proteins/peptides are important for its function. However, there is very limited study that investigates what factors are involved in rG4 that drive the rG4-protein/peptide interaction. Here we study and uncover the effect of RNA sequence context and stereochemistry on G-quadruplex-peptide interaction. Using rG4-binding RHAU53 peptide as an example, we report that the number of G-quartet, thermostability, overhanging nucleotides, and RNA base chirality have an impact on rG4-RHAU53 binding. Notably, our data also demonstrate that RHAU53 preferentially binds to 5′ G-quartet over 3' G-quartet, and showcase that RHAU53 interacts with unnatural L-rG4 for the first time. Our findings reported here offer unique insights to the potential development of targeting tools that recognize rG4 structure and rG4-binding peptide/protein. Image 1 • Effect of RNA sequence and stereochemistry on G-quadruplex-RHAU53 binding uncovered. • RHAU53 preferentially binds to 5′ G-quartet over 3′ G-quartet. • RHAU53 tends to interact with D-rG4 than L-rG4. • Biochemical and Biophysical Research Communications. [ABSTRACT FROM AUTHOR]

Augmented Reality (AR) has become a hot topic. It seems AR is finally becoming ready for the generals: Public securities have been using AR glasses to assist their public patrol activities, the museum offers the AR glasses to enhance the visitor experience, the oil evaporation workers wear AR headset to help their evaporation operation, etc. However, the one component that is probably most limiting today's popularization is the display's image quality. This paper addressed the image quality of see‐through real scene for AR glasses. Michelson contrast or namely luminance modulation, is measured to evaluate the quality of an see‐through optics. In this paper, we studied the Michelson contrast at different locations of the optics of AR displays. Two types of AR displays were selected for the evaluation and measurement. This paper discussed the two favorable AR type technologies: waveguide and combiner (prism‐combiner). [ABSTRACT FROM AUTHOR]

The HUD (Head‐Up Display) is an optical display system that is commonly used in aircraft as a flight aid to project aircraft flight information onto the display screen (often a type of transparent flat lens) directly in front of the pilot's field of view. This allows the pilot to maintain a level view while taking into account instrument parameters and external visual references in the same field of view. HUDs allow pilots to see crucial navigation, flying, and energy management data on a screen at eye level without having to glance down at their instruments or take their eyes off the outside world. It has been demonstrated that HUDs lessen the pilot workload, improve situational awareness, and decrease accidents. Thus, it is crucial to characterize optical performance and image quality accurately and precisely for aircraft HUDs. In this paper, we reviewed the parameters of optical performance and image quality for aviation‐type HUDs applied under high ambient light levels. [ABSTRACT FROM AUTHOR]

The augmented reality (AR) display is one of the arising display technologies. An AR display system creates an immersive aspect of the real environment by generating the virtual image with a micro‐display and fusing the external real‐time image into the same scene. Unlike traditional LCDs, the AR display has a very different image formation mechanism that allows its testing method to be different from conventional methods. This paper introduces some of the main issues related to the real‐scene fused with the virtual image under ambient conditions. [ABSTRACT FROM AUTHOR]

Currently, photobiological safety of electronic display devices is highly concerned by product manufacturers. The right risk group classifications for certain products are likely not easy, because many factors will affect the measurement of quantities relating to optical radiation hazards and led to high uncertainty. How to measure the photobiological safety of electronic display devices and what are main factors in the safety assessment, are the topics in this study. [ABSTRACT FROM AUTHOR]

The measurement of optical performance such as luminance, chromaticity for augmented reality/virtual reality (AR/VR) display is significantly different from that of conventional real display. The spatial coordinates of the virtual image need to be described with a V-H angular coordinate system. The image beam to be measured at each viewing field comes through exit pupil of the virtual imaging device, which is difficult for the measurement of the virtual image by traditional luminance meters. In this paper, we proposed a new optical measurement system which simulates the imaging mechanism of the human eye. A 5mm aperture is placed in front of the focal point of the imaging lens of the luminance meter, which works as the entrance pupil of the luminance meter and is fit to inside of the exit pupil of the virtual imaging device, and the field of view (FOV) keep constant at different imaging distances. The combination of a spectrometer and a CCD imaging device is equipped to determine the optical and image parameters of AR/VR displays. [ABSTRACT FROM AUTHOR]

Augmented Reality (AR) creates a photorealistic view by either superimposing or subtracting computer‐generated scenes onto a user's view of the real physical world. The challenge for the AR display is to convince the user whether it is effective by conveying the sense of reality. It can be quantified into several topics: 1) Virtual image quality in the dark room; 2) Virtual image quality with the bright background as an example of color image quality degeneration shown in Figure 1; and 3) Real world scenes effected by the optics and virtual image of the AR display. 4) Performance of the virtual image merged with the real scene. [ABSTRACT FROM AUTHOR]

VR/AR eyewear displays are truly here in 2018, but the challenge remains. One of the potential benefits of VR/AR applications is the immersive experience with the virtual world that can suspend disbelief. However, the drawback is that the technology still needs improvement. Currently, most commercially available VR displays may only output 10‐20 ppd (pixel per degree) in angular resolution due to the limitation of the microdisplays. However, our human eye can dissolve the image details up over 60 ppd. Thus, the lack in image resolution can easily lose its capability of fooling the user. In order to improve the design such as the microdisplay panel or imaging optics, we need to evaluate the characteristics of the virtual images in the visual aspect. In conventional display measurement, pixel angular resolution is applied, but the pixel number is only a physical definition. Additionally, for a small pixel structure, it may have high spot luminance and low average image luminance which would cause an uncomfortable stimulus to the user. Therefore, what is a better way to define image resolution in VR/AR displays? In this work, we reviewed the current methods proposed in IEC TC110 on image quality. Then, some of the key factors that involve the image resolution measurement would be presented. We first reviewed the fundamental aspects of visual‐spatial perception and the mechanism of the human eye, and then we explained why such display limits the image quality of VR/AR display systems. In addition, we presented other measurement parameters including the newly proposed term ‐ pixel angular density, MTF (modulation transfer function) as well as the virtual image quality in static and moving picture conditions. These parameters were addressed in this work from introducing the definition to how and why they are necessary to test. An example of measurement in static picture resolution is shown in Figure1. The contrast modulation measurement is performed to determine static picture resolution. The test patterns and the calculation formula are critical in the measurement. The goal of this work is to provide some essential and fundamental guidelines to manufactures and engineers in the image resolution measurement of VR/AR systems. 1 An example of contrast modulation measurement [ABSTRACT FROM AUTHOR]