Designing augmented reality for the classroom

Augmented reality (AR) has recently received a lot of attention in education. Multiple AR systems for learning have been developed and tested through empirical studies often conducted in lab settings. While lab studies can be insightful, they leave out the complexity of a classroom environment. We developed three AR learning environments that have been used in genuine classroom contexts, some of them being now part of classroom regular practices. These systems and the learning activities they provide have been co-designed with teachers, for their own classrooms, through multiple cycles of prototyping and testing. We present here the features that emerged from these co-design cycles and abstract them into design principles.     

Calibration-free augmented reality in perspective

This paper deals with video-based augmented reality and proposes an algorithm for augmenting a real video sequence with views of graphics objects without metric calibration of the video camera by representing the motion of the video camera in projective space. A virtual camera, by which views of graphics objects are generated, is attached to a real camera by specifying image locations of the world coordinate system of the virtual world. The virtual camera is decomposed into calibration and motion components in order to make full use of graphics tools. The projective motion of the real camera recovered from image matches has the function of transferring the virtual camera and makes the virtual camera move according to the motion of the real camera. The virtual camera also follows the change of the internal parameters of the real camera. This paper shows the theoretical and experimental results of our application of nonmetric vision to augmented reality     

On the precision of third person perspective augmented reality for target designation tasks

The availability of powerful consumer-level smart devices and off-the-shelf software frameworks has tremendously popularized augmented reality (AR) applications. However, since the built-in cameras typically have rather limited field of view, it is usually preferable to position AR tools built upon these devices at a distance when large objects need to be tracked for augmentation. This arrangement makes it difficult or even impossible to physically interact with the augmented object. One solution is to adopt third person perspective (TPP) with which the smart device shows in real time the object to be interacted with, the AR information and the user herself, all captured by a remote camera. Through mental transformation between the user-centric coordinate space and the coordinate system of the remote camera, the user can directly interact with objects in the real world. To evaluate user performance under this cognitively demanding situation, we developed such an experimental TPP AR system and conducted experiments which required subjects to make markings on a whiteboard according to virtual marks displayed by the AR system. The same markings were also made manually with a ruler. We measured the precision of the markings as well as the time to accomplish the task. Our results show that although the AR approach was on average around half a centimeter less precise than the manual measurement, it was approximately three times as fast as the manual counterpart. Additionally, we also found that subjects could quickly adapt to the mental transformation between the two coordinate systems.     

Collaborative visualization in augmented reality

The authors discuss Studierstube, a low-cost augmented reality system. The system features true stereoscopy, 3D interaction, individual viewpoints and customized views for multiple users, and unhindered natural collaboration     

A system for supporting paper-based augmented reality

In this paper, we aim to implement augmented reality (AR) on distant text documents or books. For this purpose, we propose a new paper-based AR system that can detect text documents in real scenes, markerize and identify them, estimate their relative 3D poses to the camera, and augment them with virtual contents. Unlike the previous paper-based AR systems (applicable to only close documents), the proposed system not only requires no detection of words or characters, but allows partial occlusions like the previous systems. In our experiments, the proposed system worked at 24 fps and could consistently achieve high identification rates for both occluded and unoccluded pages.     

基于ORB自然特征的AR实时系统实现

针对当前基于自然特征的增强现实效率低,提出一种新的基于ORB自然特征的实时注册方法。提取视频帧与基准图像中的ORB特征点,使用汉明距离匹配,利用RANSAC算法筛选得到最佳匹配点对,确定摄像机的位姿。将三维虚拟物体叠加到真实场景中,达到虚实结合的效果。实验表明,在不同尺度角度、一定环境光变化、复杂背景和基准图像部分遮挡的情况下,该AR系统都具有良好的性能,跟踪定位准确度高,速度基本达到实时要求。     

增强现实中抛掷动作速度的预测

结合增强现实抛掷虚拟物体的应用背景,提出一种新的预测抛掷动作速度的方法。首先利用二维三次多项式函数分段循环拟合抛掷动作的速度曲线,并运用函数的最大值分析出抛掷动作速度的大小;然后利用三维三次多项式函数分段循环拟合抛掷动作的轨迹曲线,由抛掷动作速度曲线的切线方向即可确定抛掷动作速度的方向。实验结果表明,可更为容易地获得抛掷动作速度的大小和方向,克服了对每个空间位置坐标准确性的依赖;同时,能保证虚拟物体和真实物体的运动轨迹一致性,有利于提高增强现实应用的运动一致性。     

Understanding augmented reality adoption trade-offs in production environments from the perspective of future employees: A choice-based conjoint study

Information Systems and e-Business Management - The implementation of augmented reality (AR) systems in production environments is associated with a variety of advantages, such as productivity...     

Distributed spatial Sensemaking on the augmented reality sandbox

International Journal of Computer-Supported Collaborative Learning - This research examines small group collaboration on the Augmented Reality (AR) Sandbox, an interactive, real-time topographical...     

A generalized registration method for augmented reality systems

In augmented reality systems, registration is one of the most difficult problems currently limiting their applications. In this paper, we propose a generalized registration method using projective reconstruction technique in computer vision. This registration method is composed of embedding and tracking. Embedding involves specifying four points to build the world coordinate system on which a virtual object will be superimposed. In this stage, any arbitrary two unrelated images or any 3×4 projective matrices with rank 3 can be used to calculate the 3D pseudo-projective coordinates of the four specified points. In the tracking process, these 3D pseudo-projective coordinates are used to track the four specified points to compute the registration matrix for augmentation. The proposed method is simple, as only four points need to be specified at the embedding stage, and the virtual object can then be easily augmented onto a real scene from a video sequence. One advantage is that the virtual objects can still be superimposed on the specified regions even when the regions are occluded in the video sequence. Another advantage of the proposed method is that the registration errors can be adjusted in real-time to ensure that they are less than certain thresholds that have been specified at the initial embedding stage. Several experiments have been conducted to validate the performance of the proposed generalized method.     

A topometric system for wide area augmented reality

We describe a system designed to facilitate efficient communication of information relating to the physical world using augmented reality (AR). We bring together a range of technologies to create a system capable of operating in real-time, over wide areas and for both indoor and outdoor operations. The central concept is to integrate localised mapping and tracking based on real-time visual SLAM with global positioning from both GPS and indoor ultra-wide band (UWB) technology. The former allows accurate and repeatable creation and visualisation of AR annotations within local metric maps, whilst the latter provides a coarse global representation of the topology of the maps. We call this a ‘Topometric System’. The key elements are: robust and efficient vision based tracking and mapping using a Kalman filter framework; rapid and reliable vision based relocalisation of users within local maps; user interaction mechanisms for effective annotation insertion; and an integrated framework for managing and fusing mapping and positioning data. We present the results of experiments conducted over a wide area, with indoor and outdoor operations, which demonstrates successful creation and visualisation of large numbers of AR annotations over a range of different locations.     

基于投影技术的增强现实注册方法

注册技术是实现增强现实应用系统的关键问题之一。实现了一种利用投影技术改进了的注册方法。这种注册方法主要包含4个步骤：（1）检测标识和特征点的位置;（2）利用投影技术跟踪摄像机;（3）计算模型视图矩阵;（4）绘制虚拟物体。在初始阶段,指定4个点建立世界坐标系,虚拟物体将会被叠加到这个坐标系上;在注册过程中,利用投影技术跟踪特征点的位置,并计算用于增强的模型视图转换。这种注册方法可以为一般的室内增强现实系统提供所需的精确度和实时性。     

Tracking for augmented reality on wearable computers

Wearable computers afford a degree of mobility that makes tracking for augmented reality difficult. This paper presents a novel object-centric tracking architecture for presenting augmented reality media in spatial relationships to objects, regardless of the objects' positions or motions in the world. The advance this system provides is the ability to sense and integrate new features into its tracking database, thereby extending the tracking region automatically. A lazy evaluation of the structure from motion problem uses images obtained from a single calibrated moving camera and applies recursive filtering to identify and estimate the 3D positions of new features. We evaluate the performance of two filters; a classic Extended Kalman Filter (EKF) and a filter based on a Recursive-Average of Covariances (RAC). Some implementation issues and results are discussed in conclusion.     

Multimedia resources In the mathematics classroom

Abstract  In a study of multimedia technology in mathematics classrooms, teachers were given a set of resources which were very mixed in character and style, and from which they could freely select. These were used in lessons over an extended period, in some cases for two years or longer. By interviewing and by observing lessons, it has been possible to draw some tentative conclusions about the relative merits of different styles of multimedia in mathematics classrooms. There was no evidence that multimedia leads to radically new ways of teaching and learning but instead it appears to be a natural continuation of the evolution of ideas for teaching with computers that took place during the 1980s.     

增强现实环境下的产品装配引导技术

以增强现实环境下引导产品装配为目标,建立了面向增强装配过程的统一信息模型,管理文字、几何和产品装配特征等可视化引导信息。采用基于标志物的视觉跟踪技术实现虚拟零件和视频中真实零件的注册定位,通过建立虚拟和真实装配场景的深度图处理增强装配场景中虚实物体的遮挡关系。利用虚实零件的注册位置把装配引导信息叠加到装配视频场景中。并开发了演示系统,分析和说明了增强现实环境下引导产品进行装配的过程。     

Head-mounted display augmented reality in manufacturing: A systematic review

Head-mounted display (HMD) augmented reality (AR) has attracted more and more attention in manufacturing activities, as it enables operators to access visual guidance in front of their view directly while freeing human's two hands. Nevertheless, HMD AR has not been widely adopted in manufacturing fields as humans expected since the release of Google Glass in 2012, and thus it is important to understand the related issues arising from the actual deployments of HMD AR on the shop floor. To the best of the authors’ knowledge, there have not been comprehensive discussions on HMD AR in manufacturing from a holistic perspective. This article aims to provide an extensive map for the distribution of HMD AR in various manufacturing activities and a systematic overview of underlying technical perspectives associated with their actual industrial applications between 2010 and 2022, involving AR visualization, tracking and registration, context awareness, human-machine interaction, as well as ergonomics and usability, which are significant for the actual AR deployments for human-centric manufacturing in Industry 5.0. It is also worth mentioning that this work presents a historical overview of the current research on the development of HMD AR, as well as a summary of the existing methods and open problems for HMD AR in manufacturing. It is helpful to understand the current technical situations of HMD AR while providing insights to deploy industrial AR applications and perform academic research in the future.     

Utilization of the microcomputer in the mathematics classroom

This study investigated the utilization of microcomputers in the secondary mathematics curriculum. A sample of 128 mathematics teachers completed a survey describing their use of the microcomputer for instruction. Results from the study suggested the microcomputer was not utilized as often as expected. Findings that describe the computer-using and non-computer-using teachers, the ways computers are used in the mathematics classroom, and the instructional environment where computers are used are reported. Suggestions are provided for improving the integration of the microcomputer into the mathematics classroom.