Multibeam and multipanel displays: Some perceptual effects of scan architecture

Abstract— Scan architectures involving multiple beams or panels provide a means of increasing display resolution. However, the spatiotemporal pattern of such a scan may differ appreciably from the sampling lattice of standard input devices. If there are discrepancies between the scan pattern used to display a sequence of spatial images and the sampling lattice used to create that sequence, the space‐time display image may not be an accurate reconstruction of the original image. To illustrate the types of error that can occur, this paper presents an analysis of the form and motion distortions that result when a standard, progressive scan is used to display computer‐generated constant‐velocity motion sequences. A summary of pertinent psychophysical research indicates why these distortions are rarely detectable and provides a basis for estimating the perceptual salience of distortions created by combinations of sampling lattices and scan patterns. Finally, an analysis of several possible parallel‐ scan architectures indicates that some will introduce relatively large temporal delays between updates of spatially adjacent areas and thereby seriously distort computer‐generated images.     

Implementation of structured display files in interactive colour graphics

This paper discusses the various types of data structure used in computers, analyses their advantages and disadvantages, and assesses their suitability for use in microprocessor-based interactive computer graphics. Its main purpose is to define a display file structure which introduces levels of hierarchy amongst the elements of computer-generated images. The use of structured display files arises from the need to assist the user of an interactive system by supplying the software tools required to allow easy manipulation of the image contents.     

Characterizing crosstalk in anaglyphic stereoscopic images on LCD monitors and plasma displays

Abstract— In 1853, William Rollman developed the inexpensive and easy to use anaglyph method for displaying stereoscopic images. Although it can be used with nearly any type of full‐color display, the anaglyph method compromises the accuracy of color reproduction, and it often suffers from crosstalk (or ghosting) between the left‐ and right‐eye image channels. Crosstalk degrades the ability of the observer to fuse the stereoscopic image, and hence reduces the quality of the 3‐D image. Crosstalk is present in various levels with most stereoscopic displays; however, it is often particularly evident with anaglyphic 3‐D images. This paper summarizes the results of two projects that characterized the presence of anaglyphic crosstalk due to spectral issues on 13 LCD monitors, 14 plasma displays, and a CRT monitor when used with 25 different pairs of anaglyph 3‐D glasses. A mathematical model was used to predict the amount of crosstalk in anaglyphic 3‐D images when different combinations of displays and glasses are used, and therefore highlight displays, glasses, and combinations thereof which exhibit lower levels of crosstalk when displaying anaglyphic 3‐D images.     

Display adaptive 3D content remapping

Glasses-free automultiscopic displays are on the verge of becoming a standard technology in consumer products. These displays are capable of producing the illusion of 3D content without the need of any additional eyewear. However, due to limitations in angular resolution, they can only show a limited depth of field, which translates into blurred-out areas whenever an object extrudes beyond a certain depth. Moreover, the blurring is device-specific, due to the different constraints of each display. We introduce a novel display-adaptive light field retargeting method, to provide high-quality, blur-free viewing experiences of the same content on a variety of display types, ranging from hand-held devices to movie theaters. We pose the problem as an optimization, which aims at modifying the original light field so that the displayed content appears sharp while preserving the original perception of depth. In particular, we run the optimization on the central view and use warping to synthesize the rest of the light field. We validate our method using existing objective metrics for both image quality (blur) and perceived depth. The proposed framework can also be applied to retargeting disparities in stereoscopic image displays, supporting both dichotomous and non-dichotomous comfort zones.     

EL displays for automotive applications

Abstract— This paper presents an overview of the display requirements for automotive applications and introduces alternating‐current thin‐film electroluminesent (ACTFEL) displays for automobiles. An ACTFEL has advantages over other displays under sunlight and low temperature conditions. Several automotive applications for transparent and multicolor EL displays are introduced in this paper.     

Displays for hand-held portable electronic products

Abstract— The hand-held electronic-product field includes most telecommunication, palm computing, and navigation products, making this a large market for smaller displays (typically from 1 to 4 in. on the diagonal). Historically, this market has demanded displays with low power and cost, rather than high image quality, as evidenced by the historical dominance of monochrome TN and STN displays. However, within these constraints there is a strong trend toward larger displays capable of higher information content, including a migration toward low-power color solutions.     

Comparison of reflective PNLCDs and reflective single‐polarizer Heilmeier guest‐host displays

In this paper, the applicability of a zero‐polarizer reflective display (PNLC) and a single‐polarizer reflective display (Heilmeier guest host) for direct‐view applications is analyzed. A measurement set‐up is designed to analyze the applicability of all types of reflective displays. Simulation of the different types of illumination caused by the environmental light is essential for this set‐up. The measurements indicate that the contrast ratio and reflectance greatly depend on the type of illumination. It is demonstrated that the worst‐case illumination for one display technology may be the best‐case illumination for another one and vice versa.     

Time‐multiplexed color image generation by viewing‐zone scanning holographic display employing MEMS‐SLM

The viewing‐zone scanning holographic display, which can enlarge both screen size and viewing zone, is modified to enable color image generation by using the time‐multiplexing technique; R, G, and B lasers sequentially illuminate a single microelectromechanical systems spatial light modulator with a high frame rate. The viewing‐zone scanning system enlarges screen size by using a magnifying imaging system and generates a large number of reduced viewing zones that are aligned in the horizontal direction by a horizontal scanner to enlarge the viewing zone. The interval of the reduced viewing zones is set to be one‐third of the width of the reduced viewing zones or less so that three sets of reduced viewing zones are generated corresponding to the three colors. Color image generation was demonstrated for a screen size of 2.0 in. and a viewing zone angle of 40.0°.     

An AMOLED pixel circuit for high image quality of 1000 ppi mobile displays in AR and VR applications

In this paper, an active‐matrix organic light‐emitting diode pixel circuit is proposed to improve the image quality of 5.87‐in. mobile displays with 1000 ppi resolution in augmented and virtual reality applications. The proposed pixel circuit consisting of three thin‐film transistors (TFTs) and two capacitors (3T2C) employs a simultaneous emission driving method to reduce the number of TFTs and the emission current error caused by variations in threshold voltage (Vth) and subthreshold slope (SS) of the low‐temperature polycrystalline silicon TFTs. Using the simultaneous emission driving method, the compensation time is increased to 90 μs from 6.5 μs achieved in the conventional six TFTs and one capacitor (6T1C) pixel circuit. Consequently, the emission current error of the proposed 3T2C pixel circuit was reduced to ±3 least significant bit (LSB) from ±12 LSB at the 32nd gray level when the variations in both the Vth and SS are ±4σ. Moreover, both the crosstalk errors due to the parasitic capacitances between the adjacent pixel circuits and due to the leakage current were achieved to be less than ±1 LSB over the entire gray level. Therefore, the proposed pixel circuit is very suitable for active‐matrix organic light‐emitting diode displays requiring high image quality.     

Electrofluidic displays: Fundamental platforms and unique performance attributes

Abstract— Electrofluidic displays transpose brilliant pigment dispersions between a fluid reservoir of small viewable area and a channel of large viewable area. Recent progress in the technology, a new multi‐stable device architecture, and a novel approach for segmented displays that can display pigment without the optical losses of pixel borders is reported. The fundamental aspects of electrofluidics that make it compelling for the next generation of e‐paper products is reviewed.     

Method to improve color reproduction on a 120‐Hz two‐field color‐sequential LCD

Conventional displays use at least three primaries for full‐color image reproduction. In this contribution, the reproduction of color images using an LCD system with two local dynamic primaries, based on a segmented backlight, will be discussed. The two primaries are chosen to minimize color error by means of total least squares. Simulation results indicate quite good color reproduction for a large set of video data even with a limited number of backlight segments. A statistical analysis of this video content shows that excellent color reproduction (?u′v′ < 0.020 for more than 99.0% of the pixels per frame) can be achieved for 74.2% of the frames using 9216 backlight segments.     

光学透视头盔显示器标定技术

光学透视头盔显示器(OSTHMD)标定是增强现实技术研究中一个具有挑战性的关键技术问题. 研究了OSTHMD标定的几种常见技术及其优缺点, 详细论述了当前最常用的OSTHMD标定法: SPAAM法, 同时提出了一种基于图像的快速标定OSTHMD的方法, 从算法复杂度方面对两种标定法进行了对比, 并采用用户自行评估法进行评估, 认为基于图像的快速标定OSTHMD的方法更为快速精准.     

Light-field head-mounted displays reduce the visual effort: A user study

Head-mounted displays (HMDs) allow the visualization of virtual content and the change of view perspectives in a virtual reality (VR). Besides entertainment purposes, such displays also find application in augmented reality, VR training, or tele-robotic systems. The quality of visual feedback plays a key role for the interaction performance in such setups. In the last years, high-end computers and displays led to the reduction of simulator sickness regarding nausea symptoms, while new visualization technologies are required to further reduce oculomotor and disorientation symptoms. The so-called vergence–accommodation conflict (VAC) in standard stereoscopic displays prevents intense use of 3D displays, so far. The VAC describes the visual mismatch between the projected stereoscopic 3D image and the optical distance to the HMD screen. This conflict can be solved by using displays with correct focal distance. The light-field HMD of this study provides a close-to-continuous depth and high image resolution enabling a highly natural visualization. This paper presents the first user-study on the visual comfort of light-field displays with a close-to-market HMD based on complex interaction tasks. The results provide first evidence that the light-field technology brings clear benefits to the user in terms of physical use comfort, workload, and depth matching performance.     

Effect of display resolution and antialiasing on the discrimination of simulated-aircraft orientation

In Experiment 1, antialiasing was found to improve performance on an orientation-discrimination task, whereas increasing display pixel-count did not. The latter finding was attributed to a decrease in image contrast associated with driving the CRT beyond its effective bandwidth. In Experiment 2, it was found that display resolution is the primary determinant of orientation-discrimination performance. This performance was not significantly improved by increasing antialiasing beyond a minimal level, suggesting that greater image detail can be substituted for antialias filtering. Finally, data obtained from an objective target-size calibration showed that nominal target size often does not accurately reflect the size (and hence distance) of simulated targets.     

Determining limits to avoid double vision in an autostereoscopic display: Disparity and image element width

Abstract— The purpose of this study was to investigate the diplopia limits for three‐dimensional stereoscopic content and to determine the main methodological issues when the limits are studied with an autostereoscopic display. One of the main issues regarding stereoscopic content is the structural features that enable the user to see stereo image as a single image. If the depth of the content is not within certain limits, the perceiver cannot see the images three dimensionally and the viewing is uncomfortable. On the other hand, if these limits are followed, the user can stereoscopically fuse the images and see the resulting three‐dimensional image correctly. Some of these limits were tested and guidelines for proper depth values for stereoscopic images will be presented.     

The auto‐geometric correction of multi‐projector for cylindrical surface using Bézier patches

Geometric calibration to projection images is an indispensable operation for projection‐based spatial display. In this paper, we propose a new method for correcting images generated in a computer onto a cylindrical surface accurately, which can project a high‐resolution projection image with pixels matching avoiding too much manual operation. Images waiting to be projected are pre‐warped according to the rough correspondence between projectors and physical surface. To solve the errors resulting from unexpected pixel shifts in overlap projection area, we fit the Bézier interpolation to the images and apply the optimization theory with added constraints to correct the projection image accurately. This optimization process, by taking the pixels with specific significance on the images as the basis of calculation, avoids the traditional ways of translating the control points of the Bézier surface directly. The final results achieve a completely accurate projection picture even if the projection surface shape is inaccurate and irregular. We present the details of the proposed accurate calibration algorithm and illustrate our method, which, with its scalability, can achieve perfect projection efficiently and accurately with experiments.     

Autostereoscopic video display with motion parallax

Abstract— A multi-viewer autostereoscopic display that provides motion parallax without encumbering the observer with special equipment is described. The display is built around a single liquid-crystal panel, from which multiple images are projected to a screen where they form the 3-D image. The display can be produced economically because it uses a single display panel and conventional optics. The primary advantage of this technique is its simplicity. Computer-generated images are supplied to the liquid-crystal panel with a single video board. 3-D television can be broadcast by a single unmodified television station (NTSC, PAL, SECAM, HDTV, etc.), and recorded and replayed in 3-D with a VCR. Applications include 3-D video arcade games, avionics, engineering workstations, scientific visualization, video phones, and 3-D television.     

Laser display with single‐mirror MEMS scanner

Abstract— While arrayed DMD and LCD microdisplays are well‐established approaches for visualization tasks, image‐forming laser scanners are an emerging technology used to build miniaturized projection displays. A directly modulated RGB‐laser module consisting of diode lasers for red and blue and a frequency‐doubled semiconductor laser for green with color combining optics form the light source for the laser scanner have been developed. Subsequent beam‐shaping optics suppresses unwanted stray light and enables optimum illumination of the scanning mirror. The MEMS device features a single scanning mirror oscillating in two directions in resonant mode. This requires appropriate data delivery realized by a custom‐made driving logic, which converts the pixel stream originally arranged in rows and columns to the Lissajous‐like spot trajectory on the screen. Additionally, the increased image brightness at the vertical and horizontal borders of the field of view (FOV) is also compensated by the modulation of laser power. Theoretical investigations of the resulting maximum achievable system transmission are presented. Different systems, such as an extremely miniaturized monochrome projection head with an integrated diode laser and a full‐color projector have been realized. Important problems to be tackled are fast analog modulation of the laser power with high resolution and improved suppression of stray light and speckle.     

Visual perception of noise in a simulated holographic display—A user study

This work explores ways to bypass the fundamental image quality limitations of displays using Computer Generated Holograms (CGHs) and, specifically, the high-frequency noise associated with phase-only holograms. Although there is a wealth of literature on building experimental holographic systems, there are no user studies to assess the performance of a holographic system projecting a dynamic two-dimensional image. In this study, 18 participants blindly compared three groups of images displayed on a conventional monitor. The first group contained the original image, the second the simulated holographic reconstruction of the original image, and the third group had the foveated reconstruction of the original image, based on the pupil position. Holograms in the second group were computed using the Fienup algorithm and the third group using the Fienup with Perceptual Don’t Care Areas (FiPDoC) algorithm, a novel algorithm that uses eye tracking to optimize image quality in CGHs. The aim of the study was to find out if the holographic display, assuming an ideal hardware, can be as good as a conventional display and whether eye tracking can help this goal. Most participants distinguished between the original image and the un-foveated simulated reconstruction. However, the participants could not differentiate between the original image and the foveated reconstruction. Thus, foveation may be essential in designing and building the first commercial holographic displays.     

A 23‐in. full‐panel‐resolution autostereoscopic LCD with a novel directional backlight system

Abstract— An autostereoscopic display that shows stereoscopic images with full‐panel resolution has been developed,¹ but it has a problem in terms of unit size. To resolve this problem, a new directional backlight system was developed, and it was applied to a prototype autostereoscopic LCD. The backlight system has two light sources — one for the right eye and the another for the left eye — and an elliptically shaped mirror that controls the direction of light from the light sources. The LCD uses a field‐sequential method which re‐writes an image for one eye and one for the other eye at a frame rate of 120 Hz, and the light sources alternately blink in synchronization with each frame so that the LCD shows full‐panel‐resolution stereoscopic images without flicker. In this paper, the new backlight system is described. The backlight system is effective for large screen such as 23 in. on the diagonal. By using this backlight system, the prototype LCD achieved practible unit size, brightness over the entire screen, and cross‐talk.