A comparative study using an autostereoscopic display with augmented and virtual reality

Advances in display devices are facilitating the integration of stereoscopic visualisation in our daily lives. However, autostereoscopic visualisation has not been extensively exploited. In this paper, we present a system that combines augmented reality (AR) and autostereoscopic visualisation. We also present the first study that compares different aspects using an autostereoscopic display with AR and virtual reality (VR), in which 39 children from 8 to 10 years old participated. In our study, no statistically significant differences were found between AR and VR. However, the scores were very high in nearly all of the questions, and the children also scored the AR version higher in all cases. Moreover, the children explicitly preferred the AR version (81%). For the AR version, a strong and significant correlation was found between the use of the autostereoscopic screen in games and seeing the virtual object on the marker. For the VR version, two strong and significant correlations were found. The first correlation was between the ease of play and the use of the rotatory controller. The second correlation was between depth perception and the game global score. Therefore, the combinations of AR and VR with autostereoscopic visualisation are possibilities for developing edutainment systems for children.     

Wide‐view augmented reality display with diffractive cholesteric liquid crystal lens array

A novel augmented reality display is proposed to achieve a field of view of 100°, while maintaining a good form factor with a glass‐thin waveguide combiner. The out‐coupler consists of an array of off‐axis diffractive lenslets with extremely low f‐number. A breadboard system is built and its performance characterized, combined with analysis and discussion of further improvement.     

保持视觉稳定性的增强现实注册算法

提出了一种保持视觉稳定性的增强现实注册算法,特征点在视频中的初匹配基于随机树检索统计得到,初步匹配的特征点采用半几何限制结合单应矩阵迭代的方法进行错误匹配排除,随后采用光流法跟踪特征点,最后根据共面POSIT算法计算出物体世界坐标系到摄像机坐标系的变换矩阵。由于采用了特征点跟踪方法,在一定程度上有效的防止了虚拟物体在视觉上的抖动。     

The effects of an augmented reality based magnetic experimental tool on students' knowledge improvement and cognitive load

While the use of experiments is important for developing students' scientific knowledge and skills, challenges may arise when teachers and students are conducting experiments in class, such as non-reusable experimental resources, safety issues and difficulties simulating some specific effects. Augmented reality (AR) technology affords an alternative approach to conducting experiments by bringing students a virtual–real mixed learning environment. In this study, taking junior high school physics knowledge on the magnetic field as an example, we designed and developed an AR-based mobile simulated experiment tool. This study investigates the effect of the AR-based experiment on students' knowledge improvement and cognitive load compared with 3D and traditional experiments. A sample of 122 ninth-grade students was randomly chosen and assigned to three groups (AR, 3D and Traditional). The results demonstrate that students in the AR group performed better than those in the 3D and Traditional groups in terms of their knowledge improvement. The AR group students also experienced the lowest cognitive load among the three groups. Moreover, students had positive perceptions about AR and 3D tools. The implications of this study are discussed.     

Enhancing augmented reality with cognitive and knowledge perspectives: a case study in museum exhibitions

ABSTRACT

In this paper, we present our results related to the definition of a methodology that combines augmented reality (AR) with semantic techniques for the creation of digital stories associated with museum exhibitions. In contrast to traditional AR approaches, we augment real-world elements by supplementing contents of a museum exhibition with additional inputs that provide new and different meanings. In this way we augment a cultural resource with respect to both its presentation and meaning. The methodology is framed in the cultural re-mediation theory and is grounded on a set of ontologies aimed at modelling a cultural resource and correlating it with external multimedia objects and resources. To provide an easy tool for the creation of museum narratives, the methodology makes use of a set of recognised practices widely adopted by museum curators that have been formalised through inference rules. The defined methodology has been experimented in a scenario related to Flemish paintings to validate the augmentation of cultural objects with two different approaches, the first basing on similarities and the second on dissimilarities.     

Binocular vision in a bi-ocular world: new-generation head-mounted displays avoid causing visual deficit

Our previous research highlighted adverse visual effects after wearing a binocular head-mounted display (HMD) for a 10 min stereoscopic visualization task. We have since proposed a theoretical, explanation based on the conflict between the depth. Such cues presented by image disparity and image focal depth. Such conflict, however, is not evident in all HMD configurations, and we replicated our early trials using a new-generation bi-ocular HMD produced by Virtuality Entertainment Ltd. Using similar, conventional optometric procedures with 50 participants, we observed no problems in the use of this display for immersion periods of to 30 min. This study demonstrates that effective HMDs can be produced through careful design and precision engineering. It also suggests a difference between the presentation of binocular and bi-ocular images and the requirements that they place on the visual system. Factors to consider in the future development of binocular displays are discussed.     

A multi‐plane optical see‐through head mounted display design for augmented reality applications

Augmented reality (AR) display technology greatly enhances users' perception of and interaction with the real world by superimposing a computer‐generated virtual scene on the real physical world. The main problem of the state‐of‐the‐art 3D AR head‐mounted displays (HMDs) is the accommodation‐vergence conflict because the 2D images displayed by flat panel devices are at a fixed distance from the eyes. In this paper, we present a design for an optical see‐through HMD utilizing multi‐plane display technology for AR applications. This approach manages to provide correct depth information and solves the accommodation‐vergence conflict problem. In our system, a projector projects slices of a 3D scene onto a stack of polymer‐stabilized liquid crystal scattering shutters in time sequence to reconstruct the 3D scene. The polymer‐stabilized liquid crystal shutters have sub‐millisecond switching time that enables sufficient number of shutters to achieve high depth resolution. A proof‐of‐concept two‐plane optical see‐through HMD prototype is demonstrated. Our design can be made lightweight, compact, with high resolution, and large depth range from near the eye to infinity and thus holds great potential for fatigue‐free AR HMDs.     

Compact see‐through near‐eye display with depth adaption

Based on the recent development of Pancharatnam–Berry deflectors and lenses, we propose a compact and lightweight near‐eye display system with depth adaption. The compact design results from the polarization selectivity of Pancharatnam–Berry deflector waveguide coupler, and the fast‐switching Pancharatnam–Berry lenses can be exploited for generating correct light fields.     

一种舞台增强现实系统的研究与实现

增强现实技术以其与用户实时交互及“虚实”高度融合的特点在各个领域都得到了迅猛发展,但在舞台艺术中的研究与应用尚少,其难点便在于演员与显示系统难以实时交互。传统舞台特效多通过视频播放获得,演员需精准配合视频,严重限制了其发挥。针对该问题,提出了一种基于红外摄像头的舞台增强现实系统,根据现场演员的舞蹈动作实时驱动特效并呈现相应的合成画面,完全解放了演员的束缚,协调了其与显示系统的人机关系,使得舞台效果的呈现由演员自主确定,而不是被动地配合视频。该系统成功应用于多个正式演出的舞台剧中,为新型的舞台互动方法提供了一种新思路。     

Stretchable,flexible, and adherable polarization volume grating film for waveguide‐based augmented reality displays

We report a stretchable, flexible, and adherable polarization volume grating (PVG) film and propose a compact optical system for augmented reality displays based on it. The Bragg reflection band shift, deflection angle change, and the mechanical robustness under stretch‐release cycles of the PVG film are also investigated.     

The development of a panorama manifestation virtual reality system for navigation and a usability comparison with a desktop system

The virtual reality (VR) system has become popular in the last two decades and is being applied increasingly to navigation studies. This study developed a panorama manifestation (PM) VR system, with six monitors forming a circular display and an interactive chair equipped with rotation sensors and operating knobs. The advantages of the PM system include a large circular display, a body-centred design, body engagement and a low set-up cost. Based on navigation experimental tasks, this system's usability was compared with that of a typical desktop (DT) system. The results showed that participants using the PM system had a significantly higher success rate and required less completion time than participants using the DT system, indicating that the PM system outperforms the DT system in terms of effectiveness and efficiency in some navigation tasks, and also suggesting that the PM system may require lower spatial cognition workload in the navigation tasks. However, the participants’ subjective evaluations of task difficulty (TD) failed to reach significance although the PM group did report a lower mean value for TD. Additionally, in the PM system, the participants’ spatial ability was more predictive to their navigation performance than that in the DT system, indicating that the PM system offered greater usability for some spatial experiments and could provide more support for participants’ navigation tasks.     

ARCosmetics: a real-time augmented reality cosmetics try-on system

A virtual cosmetics try-on system provides a realistic try-on experience for consumers and helps them efficiently choose suitable cosmetics. In this article, we propose a real-time augmented reality virtual cosmetics try-on system for smartphones (ARCosmetics), taking speed, accuracy, and stability into consideration at each step to ensure a better user experience. A novel and very fast face tracking method utilizes the face detection box and the average position of facial landmarks to estimate the faces in continuous frames. A dynamic weight Wing loss is introduced to assign a dynamic weight to every landmark by the estimated error during training. It balances the attention between small, medium, and large range error and thus increases the accuracy and robustness. We also designed a weighted average method to utilize the information of the adjacent frame for landmark refinement, guaranteeing the stability of the generated landmarks. Extensive experiments conducted on a large 106-point facial landmark dataset and the 300-VW dataset demonstrate the superior performance of the proposed method compared to other state-of-the-art methods. We also conducted user satisfaction studies further to verify the efficiency and effectiveness of our ARCosmetics system.     

基于元胞自动机的增强现实标记识别算法

增强现实系统中标记识别一直是增强现实系统的瓶颈,占用了系统处理的大部分时间,即使采用规则几何形式的标记,对于实时要求很高的增强现实系统而言,其识别算法的效果和实时性也是不理想的,因此提出了一种利用应用元胞自动机模型,利用给定的演化规则,改进在增强现实系统中标记识别的算法,并在ARTOOLKIT系统中做了具体实现.实验结果表明,改进的算法的实时性和识别效果均有了很大的提高.     

An augmented reality human–computer interface for object localization in a cognitive vision system

The European Cognitive Vision project VAMPIRE uses mobile AR-kits to interact with a visual active memory for teaching and retrieval purposes. This paper describes concept and technical realization of the used mobile AR-kits and discusses interactive learning and retrieval in office environments, and the active memory infrastructure. The focus is on 3D interaction for pointing in a scene coordinate system. This is achieved by 3D augmented pointing, which combines inside-out tracking for head pose recovery and 3D stereo human–computer interaction. Experimental evaluation shows that the accuracy of this 3D cursor is within a few centimeters, which is sufficient to point at an object in an office. Finally, an application of the cursor in VAMPIRE is presented, where in addition to the mobile system, at least one stationary active camera is used to obtain different views of an object. There are many potential applications, for example an improved view-based object recognition.     

Toward quality texture display: vibrotactile stimuli to modify material roughness sensations

For industrial purposes such as product design, texture displays should deliver a quality sense of touch to users. We have developed a vibrotactile texture display that uses real materials such as fabric, wood, and leather to enable the presentation of quality textures to users. By applying two types of vibrotactile stimuli to users’ finger pads through the materials, their fine and macro roughness sensations can be selectively modified while maintaining their original perceptual characteristics. This approach is effective for different types of textures such as paper, wood, leather, and cloth unless they possess strong damping properties that may attenuate the vibratory stimuli applied through them.     

An interactive 3D movement path manipulation method in an augmented reality environment

In this paper, we evaluate a path editing method using a tangible user interface to generate and manipulate the movement path of a 3D object in an Augmented Reality (AR) scene. To generate the movement path, each translation point of a real 3D manipulation prop is examined to determine which point should be used as a control point for the path. Interpolation using splines is then used to reconstruct the path with a smooth line. A dynamic score-based selection method is also used to effectively select small and dense control points of the path. In an experimental evaluation, our method took the same time and generated a similar amount of errors as a more traditional approach, however the number of control points needed was significantly reduced. For control manipulation, the task completion time was quicker and there was less hand movement needed. Our method can be applied to drawing or curve editing methods in AR educational, gaming, and simulation applications.     

Collaborative use of mobile augmented reality with paper maps

The popularity of augmented reality (AR) applications on mobile devices is increasing, but there is as yet little research on their use in real-settings. We review data from two pioneering field trials where MapLens, a magic lens that augments paper-based city maps, was used in small-group collaborative tasks. The first study compared MapLens to a digital version akin to Google Maps, the second looked at using one shared mobile device vs. using multiple devices. The studies find place-making and use of artefacts to communicate and establish common ground as predominant modes of interaction in AR-mediated collaboration with users working on tasks together despite not needing to.     

An augmented reality system to guide radio‐frequency tumour ablation

Radio‐frequency ablation is a difficult operative task that requires a precise needle positioning in the centre of the pathology. This article presents an augmented reality system for hepatic therapy guidance that superimposes in real‐time 3D reconstructions (from CT acquisition) and a virtual model of the needle on external views of a patient. The superimposition of reconstructed models is performed with a 3D/2D registration based on radio‐opaque markers stuck on to the patient's skin. The characteristics of the problem (accuracy, robustness and time processing) led us to develop automatic procedures to extract and match the markers and to track the needle in real time. Experimental studies confirmed that our algorithms are robust and reliable. Preliminary experiments conducted on a human abdomen phantom showed that our system is highly accurate (needle positioning error within 3 mm) and enables the surgeon to reach a target in less than 1 minute on average. Our next step will be to perform an in vivo evaluation. Copyright © 2005 John Wiley & Sons, Ltd.     

Depth perception in shuffleboard: Depth cues effect on depth perception in virtual and augmented reality system

The virtual reality (VR) and augmented reality (AR) applications have been widely used in a variety of fields; one of the key requirements in a VR or AR system is to understand how users perceive depth in the virtual environment and AR. Three different graphics depth cues are designed in shuffleboard to explore what kind of graphics depth cues are beneficial for depth perception. We also conduct a depth‐matching experiment to compare performance in VR and AR systems using an optical see‐through head‐mounted display (HMD). The result shows that the absolute error increases as the distance becomes farther. Analysis from the inverse of distance shows that box depth cues have a significant effect on depth perception, while the points depth cues and line depth cues have no significant effect. The error in diopter in AR experiment is lower than that in VR experiment. Participants in the AR experiment under medium illuminance condition have less error than those under low and high illuminance conditions. Men have less error than women in certain display conditions, but the advantage disappears when there is a strong depth cue. Besides, there is no significant effect of completion time on depth perception.