Improving content visibility for high‐ambient‐illumination viewable display and energy‐saving display

Abstract— Nowadays, low‐contrast viewing of LC displays (LCDs) occurs very often, which includes the viewing of mobile LCDs at high ambient illumination and the viewing of LCDs at low‐power mode. These cases result in low‐content visibility and low contrast, leading to an unpleasant viewing experience. In this paper, a technique to improve the perceived contrast and visibility of images at low‐contrast viewing conditions is proposed. The proposed approach enhances image brightness with content and ambient adaptive image brightening and highlights visual parts and boundaries with non‐photorealistic rendering. The proposed technique enables longer battery life for mobile LC devices and makes mobile LC devices viewable at high ambient illumination. It also enables TVs with extreme low‐power consumption and smart‐grid responsive TVs.     

Effect of number of views to the viewing experience with autostereoscopic 3‐D displays

Abstract— The observers' 3‐D viewing experience when the way the content is created and shown on an autostereoscopic 3‐D display alternate is evaluated. The observer's depth impression, and the perceived contour accuracy and image naturalness or peskiness of the content shown on a 3‐D display, has been investigated. In addition, the consequences of the way the content is created to the results from the optical characterization for the same display have been studied. The alternation of the content was realized in two different ways. Firstly, the number of views for creating the image was varied. Two, five, and 14 views were used; the main focus being on testing the same display and treating it as an ordinary two‐view and a 14‐view display with inter‐sub‐view crosstalk. Also, the intermediate condition where five views with non‐uniform view‐specific crosstalk were used has been investigated. Secondly, the way the content is created was varied by using images with computer‐generated content and photos. The effect of these parameters on viewing experience as such and especially the effect of 3‐D crosstalk on the viewing experience were studied.     

Viewing‐angle‐switching device based on array of optical micro‐rods incorporated with electrophoretic material systems

We have successfully demonstrated a control device for a viewing angle that enables switching between two states, a wide‐viewing angle, and a narrow‐viewing angle. It is composed of a light‐transmitting portion formed with an array of optical micro‐rods and a shielding/transmitting changeable portion of cross stripes designed with electrophoretic material systems consisting of black particles and an optically transparent medium. When the black particles are fully dispersed in the optically transparent medium, the cross stripe portion plays the role of a non‐transmitting material as the shielding portion in a similar manner to a conventional viewing angle control film. When the black particles are completely gathered electronically to one side in the optically transparent medium, in contrast, the cross stripe portion filled by the optically transparent medium can transmit incident light. These functions allow us to select electrically either of two modes between a limited viewing angle and a non‐limited viewing angle. The optical properties for the limited viewing angle mode were +/?30° of the visible angle and 50% of the transmittance, and the one for the non‐limited viewing mode was 58% of the transmittance. The response time from the narrow‐viewing angle to wide‐viewing angle was 1 s at 20 V of applied voltage.     

A mixed methods assessment of students' flow experiences during a mobile augmented reality science game

Current studies have reported that secondary students are highly engaged while playing mobile augmented reality (AR) learning games. Some researchers have posited that players' engagement may indicate a flow experience, but no research results have confirmed this hypothesis with vision‐based AR learning games. This study investigated factors related to students' engagement – as characterized by flow theory – during a collaborative AR, forensic science mystery game using mobile devices. School Scene Investigators: The Case of the Stolen Score Sheets is a vision‐based AR game played inside the school environment with Quick Response codes. A mixed methods approach was employed with 68 urban middle school students. Data sources included pre‐ and post‐surveys, field observations and group interviews. Results showed that neither gender nor interest in science was an important predictor of variability in flow experience. Gaming attitude uniquely predicted 23% of the variance in flow experience. Student flow experience features included a flash of intensity, a sense of discovery and the desire for higher performance. The findings demonstrated a potential for mobile AR science games to increase science interest and help students learn collaboration skills. Implications for future research concerning mobile AR science games are discussed.     

Reduced cross‐talk in shutter‐glass‐based stereoscopic LCD

Abstract— It is expected that 3‐D will be the next step in the enhanced viewing experience. At present, there are two competing 3‐D technologies for glasses‐based consumer TVs: active shutter glasses and passive polarized glasses. With the ongoing reduction in response time of liquid‐crystal displays (LCDs), this article will focus on shutter‐glass‐based stereoscopic LCDs. In this paper, the properties of such a display system is described and it is demonstrated that by adding a line‐scanning backlight, the cross‐talk can be reduced to less than 1.4%, allowing for excellent 3‐D portrayal. For images of extreme contrast, this is perceivable, but not judged annoying by a panel of expert viewers. Which characteristics of the display and shutter glasses that should be optimized to create an inexpensive, cross‐talk‐free, 3‐D LCD are discussed.     

A common approach to characterizing autostereoscopic and polarization‐based 3‐D displays

Abstract— Autostereoscopic and polarization‐based stereoscopic 3‐D displays recreate 3‐D images by providing different images in the two eyes of an observer. This aim is achieved differently for these two families of 3‐D displays. It is shown that viewing‐angle measurements can be applied to characterize both types of displays. Viewing‐angle luminance measurements are made at different locations on the display surface for each view emitted by the display. For autostereoscopic displays, a Fourier‐optics instrument with an ultra‐high‐angular‐resolution VCMaster3D is used. For polarization‐based displays, a standard Fourier‐optics instrument with additional glass filters is used. Then, what will be seen by an observer in front of the display is computed. Monocular and binocular quality criteria (left‐ and right‐eye contrast, 3‐D contrast) was used to quantify the ability to perceive depth for any observer position. Qualified monocular and binocular viewing spaces (QMVS and QBVS) are deduced. Precise 3‐D characteristics are derived such as maximum 3‐D contrast, optical viewing freedom in each direction, color shifts, and standard contrast. A quantitative comparison between displays of all types becomes possible.     

A systematic framework for on‐line calibration of a head‐mounted projection display for augmented‐reality systems

Abstract— Augmented reality (AR) is a technology in which computer‐generated virtual images are dynamically superimposed upon a real‐world scene to enhance a user's perceptions of the physical environment. A successful AR system requires that the overlaid digital information be aligned with the user's real‐world senses — a process known as registration. An accurate registration process requires the knowledge of both the intrinsic and extrinsic parameters of the viewing device and these parameters form the viewing and projection transformations for creating the simulations of virtual images. In our previous work, an easy off‐line calibration method in which an image‐based automatic matching method was used to establish the world‐to‐image correspondences was presented, and it is able to achieve subpixel accuracy. However, this off‐line method yields accurate registration only when a user's eye placements relative to the display device coincides with locations established during the offline calibration process. A likely deviation of eye placements, for instance, due to helmet slippage or user‐dependent factors such as interpupillary distance, will lead to misregistration. In this paper, a systematic on‐line calibration framework to refine the off‐line calibration results and to account for user‐dependent factors is presented. Specifically, based on an equivalent viewing projection model, a six‐parameter on‐line calibration method to refine the user‐dependent parameters in the viewing transformations is presented. Calibration procedures and results as well as evaluation experiments are described in detail. The evaluation experiments demonstrate the improvement of the registration accuracy.     

2‐D/3‐D switchable displays

Abstract— In this paper, the design of a lenticular‐based 2‐D/3‐D display for mobile applications is described. This display combines look‐around capability with good 3‐D resolution. In order to allow high‐resolution datagraphic applications, a concept based on actively switched lenses has been developed. A very noticeable problem for such displays is the occurrence of dark bands. Despite slanting the lenticular and defocusing the lens, banding becomes unacceptable when the display is viewed from an angle. As a solution, fractional viewing systems to reduce the banding intensity by almost two orders of magnitude is introduced. The resulting 3‐D display can be viewed from any horizontal direction without banding.     

Mixing virtual and real scenes in the site of ancient Pompeii

This paper presents an innovative 3D reconstruction of ancient fresco paintings through the real‐time revival of their fauna and flora, featuring groups of virtual animated characters with artificial‐life dramaturgical behaviours in an immersive, fully mobile augmented reality (AR) environment. The main goal is to push the limits of current AR and virtual storytelling technologies and to explore the processes of mixed narrative design of fictional spaces (e.g. fresco paintings) where visitors can experience a high degree of realistic immersion. Based on a captured/real‐time video sequence of the real scene in a video‐see‐through HMD set‐up, these scenes are enhanced by the seamless accurate real‐time registration and 3D rendering of realistic complete simulations of virtual flora and fauna (virtual humans and plants) in a real‐time storytelling scenario‐based environment. Thus the visitor of the ancient site is presented with an immersive and innovative multi‐sensory interactive trip to the past. Copyright © 2005 John Wiley & Sons, Ltd.     

Efficient lookup table based camera pose estimation for augmented reality

Until now, exising camera pose estimation methods for the widely used square marker‐based augmented reality (AR) are either highly sensitive to noise or much time consuming, and developers have to work hard to find the proper trade‐off between computational speed and quality in mobile AR applications where computational resources are limited. The major difficulty is that only the four corner points of the square AR marker are available, and no redundant point correspondences can be used for a stable estimation. To solve this problem, an efficient lookup table (LUT)‐based non‐iterative solution is presented in this paper that achieves high stability in the presence of noise better than the most robust and accurate iterative solutions in the field, with the same level of accuracy and a much lower computational complexity. Our central idea consists of extracting a key parameter β from the camera pose and creating a LUT for β by taking the symmetrical structure of the square marker into account, thereby exploiting additional information. Copyright © 2011 John Wiley & Sons, Ltd.     

Dual-view holographic AR display based on Bragg mismatched reconstruction of the holographic optical element

A method for dual-view holographic display based on Bragg mismatched reconstruction of holographic optical element (HOE) is proposed. Under the Bragg mismatched condition, the reconstructed images are guided into two separated viewing zones to realize dual-view holographic display. Meanwhile, the viewing angle of each perspective is increased to 11.2°, which is almost 2.5 times as large as the traditional holographic display system. The design process of HOE is simple only by interference of plane reference wave and converging spherical signal wave, which has high practicability. Furthermore, the HOE can mix the virtual 3D image with real-world scenes, which could implement augmented reality (AR) display. Experiments validate that the proposed system can achieve dual-view holographic AR three-dimensional (3D) display with accommodation effect.     

Electro‐optical characteristics and optimization of vertically aligned STN‐LCDs

A new LCD for high‐duty passive‐matrix driving, referred to as a vertically aligned (VA) STN‐LCD, characterized by high transmittance and a high contrast ratio, has been developed. This LCD can display black‐and‐white images by using crossed polarizers without the use of a color compensator because the LCD has almost zero retardation at the initial alignment state. A fabricated black‐and‐white VA‐STN‐LCD without a black matrix shows high transmittance (>15%) and contrast (CR > 100) under 1/240‐duty direct‐multiplex driving.     

Human–battery interaction on mobile phones

Mobile phone users have to deal with limited battery lifetime through a reciprocal process we call human–battery interaction. We conducted three user studies in order to understand human–battery interaction and discover the problems in existing designs that prevent users from effectively dealing with the limited battery lifetime. The studies include a large-scale international survey, two long-term field trials including quantitative battery logging and qualitative inquiries, and structured interviews with twenty additional mobile phone users. We evaluated various aspects of human–battery interaction, including charging behavior, battery indicators, user interfaces for power-saving settings, user knowledge, and user reaction. We find that mobile phone users can be categorized into two types regarding human–battery interaction and often have inadequate knowledge regarding phone power characteristics. We provide qualitative and quantitative evidence that problems in state-of-the-art user interfaces have led to under-utilized power-saving settings, under-utilized battery energy, and dissatisfied users. Our findings provide insights into improving mobile phone design for users to effectively deal with the limited battery lifetime. Our work is the first to systematically address human–battery interaction on mobile phones and is complementary to the extensive research on energy-efficient design for a longer battery lifetime.     

Characterizing image quality of autostereoscopic displays by using the maximum luminance at each viewing position

A metric of the 3D image quality of autostereoscopic displays based on optical measurements is proposed. This metric uses each view's luminance contrast, which is defined as the ratio of maximum luminance at each viewing position to total luminance at that position. Conventional metrics of the autostereoscopic display based on crosstalk, which uses “wanted” and “unwanted” lights. However, in case of the multiple‐views‐type autostereoscopic displays, it is difficult to distinguish exactly which lights are wanted lights and which are unwanted lights. This paper assumes that the wanted light has a maximum luminance at the good stereoscopic viewing position, and the unwanted light also has a maximum luminance at the worst pseudo‐stereoscopic viewing position. By using the maximum luminance that is indexed by view number of the autostereoscopic display, the proposed method enables characterizing stereoscopic viewing conditions without using wanted/unwanted light. A 3D image quality metric called “stereo luminance contrast,” the average of both eyes' contrast, is proposed. The effectiveness of the proposed metric is confirmed by the results of optical measurement analyses of different types of autostereoscopic displays, such as the two‐view, scan‐backlight, multi‐view, and integral.     

Improving scientific application execution on android mobile devices via code refactorings

The increasing number of mobile devices with ever‐growing capabilities makes them useful for running scientific applications. However, these applications have high computational demands, whereas mobile devices have limited capabilities when compared with non‐mobile devices. More importantly, mobile devices rely on batteries for their power supply. We initially measure the battery consumption of different versions of known micro‐benchmarks representing common programming primitives found in scientific applications. Then, we analyze the performance of such micro‐benchmarks in CPU‐intensive mobile applications. We apply good programming practices and code refactorings to reduce battery consumption of scientific mobile applications. Our results show the reduction in energy usage from applying these refactorings to three scientific applications, and we consequently propose guidelines for high‐performance computing applications. Our focus is on Android, the dominant mobile operating system. As a long‐term contribution, our results represent one more step in the progress towards hybrid distributed infrastructures comprising fixed and mobile nodes, that is, the so‐called mobile grids. Copyright © 2016 John Wiley & Sons, Ltd.     

Design conditions for attractive reality in mobile‐type 3‐D display

Abstract— An autostereoscopic 3‐D display suitable for the mobile environment is prototyped and evaluated. First, the required conditions for a 3‐D display in a mobile environment are considered, and the three major requirements are clarified: small size, viewing‐position flexibility, and application support. An application of a mobile‐type 3‐D display should be different from that of a large‐sized 3‐D display because a mobile‐type 3‐D display cannot realize the feeling of immersion while large‐sized 3‐D displays can realize it easily. From this assumption, it is considered that it is important to realize the feeling to handle a 3‐D image. Three types of 3‐D displays are developed to satisfy these requirements. They are subjectively evaluated to confirm their attractiveness. Results of the tests show that intuitive interaction can increase the reality of the 3‐D image in the sense of unity and also can improve the solidity and depth impression of the 3‐D image.     

Improvement of battery lifetime in software-defined network using particle swarm optimization based cluster-head gateway switch routing protocol with fuzzy rules

The software-defined network (SDN) is one of the network architectures, in which the data plane and control plane is divided from each other, and the network can be handled using a sensibly centralized controller and this method is adopted to reconfigure the wireless sensor network automatically. In this article, to implement the SDN in MANET, in which control nodes can be chosen in SDN dynamically for the activation of MANET function to allocate the works to other mobile nodes to the base station. However, in the field of mobile ad hoc networks, the network lifetime, and battery lifetime is one of the major problems and the energy consumption can play a significant rule for the transmission of data in the SDN. Therefore, in this article, particle swarm optimization (PSO) based CGSR (cluster-head gateway switch routing protocol) algorithm with fuzzy rules is proposed to increase the network lifetime of battery powered mobile nodes by reducing the energy consumptions of each node in software-defined MANET. In this proposed method, a routing method that can permit various mobile nodes with low battery power to transmits the data from source node to base station. We design a PSO based CGSR routing protocol by selecting the routing mobile nodes using fuzzy rules for packet transmission. In CGSR process, the formation of cluster and selection of cluster head is executed depending on the particle swarm optimization method. This proposed routing protocol can be used to enhance the battery lifetime by extension of the network lifetime with numerical analysis for efficient route node selection.     

Battery-aware rate adaptation for extending video streaming playback time

Multimedia streaming applications are computation and network intensive that put a high demand on battery usage of mobile devices. Battery usage forms an important metric in user satisfaction, as increased battery consumption results in faster battery depletion and eventually leads to battery outage. In this paper, we propose an adaptation technique, referred as Battery-Aware Rate Adaptation (BARA) scheme, which adapts to the appropriate bit rate to prolong the battery lifetime. BARA considers both the wireless channel conditions, as well as the device’s battery level, to determine the best transmission rate for optimizing the mobile battery consumption. Actual experiment and simulation results corroborate that compared to the conventional techniques, BARA can save more than 40% of battery power, while extending the video playback time by 20%.

     

Using augmented reality to support a software editing course for college students

This study aimed to explore whether integrating augmented reality (AR) techniques could support a software editing course and to examine the different learning effects for students using online‐based and AR‐based blended learning strategies. The researcher adopted a comparative research approach with a total of 103 college students participating in the study. The experimental group (E.G.) learned with the AR‐based contents, while the control group (C.G.) learned with the online‐based support. The findings demonstrated the potential of AR techniques for supporting students' learning motivation and peer learning interaction, and the AR‐based contents could be used as scaffolding to better support blended learning strategies. The AR‐based learning interaction could also be a trigger arousing learners' interest in becoming active learners and the students presented great learning involvement after the AR‐based supports were removed, while the learners in the C.G. were passive once the supports had been removed. Moreover, it was found that (1) their lack of experience with AR interaction and applications, (2) the slow speed of the Internet in the school, (3) the affordances of each learner's mobile learning devices, (4) the screen size of the learning interface and (5) the overloading of the learning information from the AR contents and teacher lectures might be the reasons why the learners were still more used to the online‐based support. It was therefore concluded that when integrating AR applications into a course, technology educational researchers should take into careful consideration the target learning content design, the amount of information displayed on the mobile screen and the affordances of the learning equipment and classroom environment so as to achieve a suitable learning scenario.     

Blue phase dual‐view liquid crystal display based on directional backlight system

We design a blue phase dual‐view liquid crystal display (BP DVLCD) based on a directional backlight system. Combining the patterned electrodes with the directional backlight system, the cross‐talk ratio is reduced to only 1.17%. Moreover, the resolution and brightness will be tripled by using field‐sequential color display. In the preferred viewing area, the BP DVLCD has a high contrast ratio of ~1700:1.