Multimedia augmented reality information system for museum guidance

This paper introduces the design and implementation of an augmented reality-based guidance system used for museum guidance. The objective of this study is to deliver the new museum guidance with intuitive and user-friendly interactions between man and machine based on computer vision technique in ubiquitous computing environment. In our design, a camera is used to capture hand motions and images of a printed guide, which are analyzed instantaneously to parse the designated actions the guidance system promptly responds with. The system can display and illustrate contextual information about 3D models of museum artifacts and multimedia materials to users in real time to compliment the museum experience. Moreover, the performance of the approach we proposed herein has been compared with that of the other alternatives with which the guidance system has also been installed for similar exhibitions. As a result, our proposed approach outperforms the other applications. The advantage of the proposed approach includes the exclusion of common tactile peripheral devices, for example, keyboard and mouse, which accordingly reduces hardware-related costs and reduces the risk of contamination in a public environment.     

Seeing Eye Phone: a smart phone-based indoor localization and guidance system for the visually impaired

In order to help the visually impaired as they navigate unfamiliar environment such as public buildings, this paper presents a novel smart phone, vision-based indoor localization, and guidance system, called Seeing Eye Phone. This system requires a smart phone from the user and a server. The smart phone captures and transmits images of the user facing forward to the server. The server processes the phone images to detect and describe 2D features by SURF and then matches them to the 2D features of the stored map images that include their corresponding 3D information of the building. After features are matched, Direct Linear Transform runs on a subset of correspondences to find a rough initial pose estimate and the Levenberg–Marquardt algorithm further refines the pose estimate to find a more optimal solution. With the estimated pose and the camera’s intrinsic parameters, the location and orientation of the user are calculated using 3D location correspondence data stored for features of each image. Positional information is then transmitted back to the smart phone and communicated to the user via text-to-speech. This indoor guiding system uses efficient algorithms such as SURF, homographs, multi-view geometry, and 3D to 2D reprojection to solve a very unique problem that will benefit the visually impaired. The experimental results demonstrate the feasibility of using a simple machine vision system design to accomplish a complex task and the potential of building a commercial product based on this design.     

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.     

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.     

A computer vision-based perception system for visually impaired

In this paper, we introduce a novel computer vision-based perception system, dedicated to the autonomous navigation of visually impaired people. A first feature concerns the real-time detection and recognition of obstacles and moving objects present in potentially cluttered urban scenes. To this purpose, a motion-based, real-time object detection and classification method is proposed. The method requires no a priori information about the obstacle type, size, position or location. In order to enhance the navigation/positioning capabilities offered by traditional GPS-based approaches, which are often unreliably in urban environments, a building/landmark recognition approach is also proposed. Finally, for the specific case of indoor applications, the system has the possibility to learn a set of user-defined objects of interest. Here, multi-object identification and tracking is applied in order to guide the user to localize such objects of interest. The feedback is presented to user by audio warnings/alerts/indications. Bone conduction headphones are employed in order to allow visually impaired to hear the systems warnings without obstructing the sounds from the environment. At the hardware level, the system is totally integrated on an android smartphone which makes it easy to wear, non-invasive and low-cost.

     

Markerless tracking system for augmented reality in the automotive industry

This paper presents a complete natural feature based tracking system that supports the creation of augmented reality applications focused on the automotive sector. The proposed pipeline encompasses scene modeling, system calibration and tracking steps. An augmented reality application was built on top of the system for indicating the location of 3D coordinates in a given environment which can be applied to many different applications in cars, such as a maintenance assistant, an intelligent manual, and many others. An analysis of the system was performed during the Volkswagen/ISMAR Tracking Challenge 2014, which aimed to evaluate state-of-the-art tracking approaches on the basis of requirements encountered in automotive industrial settings. A similar competition environment was also created by the authors in order to allow further studies. Evaluation results showed that the system allowed users to correctly identify points in tasks that involved tracking a rotating vehicle, tracking data on a complete vehicle and tracking with high accuracy. This evaluation allowed also to understand the applicability limits of texture based approaches in the textureless automotive environment, a problem not addressed frequently in the literature. To the best of the authors’ knowledge, this is the first work addressing the analysis of a complete tracking system for augmented reality focused on the automotive sector which could be tested and validated in a major benchmark like the Volkswagen/ISMAR Tracking Challenge, providing useful insights on the development of such expert and intelligent systems.     

Interactive mixed reality white cane simulation for the training of the blind and the visually impaired

This paper presents a mixed reality tool developed for the training of the visually impaired based on haptic and auditory feedback. The proposed approach focuses on the development of a highly interactive and extensible Haptic Mixed Reality training system that allows visually impaired to navigate into real size Virtual Reality environments. The system is based on the use of the CyberGrasp™ haptic device. An efficient collision detection algorithm based on superquadrics is also integrated into the system so as to allow real time collision detection in complex environments. A set of evaluation tests is designed in order to identify the importance of haptic, auditory and multimodal feedback and to compare the MR cane against the existing Virtual Reality cane simulation system.     

Indirect augmented reality

Developing augmented reality (AR) applications for mobile devices and outdoor environments has historically required a number of technical trade-offs related to tracking. One approach is to rely on computer vision which provides very accurate tracking, but can be brittle, and limits the generality of the application. Another approach is to rely on sensor-based tracking which enables widespread use, but at the cost of generally poor tracking performance. In this paper we present and evaluate a new approach, which we call Indirect AR, that enables perfect alignment of virtual content in a much greater number of application scenarios.To achieve this improved performance we replace the live camera view used in video see through AR with a previously captured panoramic image. By doing this we improve the perceived quality of the tracking while still maintaining a similar overall experience. There are some limitations of this technique, however, related to the use of panoramas. We evaluate these boundaries conditions on both a performance and experiential basis through two user studies. The result of these studies indicates that users preferred Indirect AR over traditional AR in most conditions, and when conditions do degrade to the point the experience changes, Indirect AR can still be a very useful tool in many outdoor application scenarios.     

Calibration-free augmented reality

Camera calibration and the acquisition of Euclidean 3D measurements have so far been considered necessary requirements for overlaying three-dimensional graphical objects with live video. We describe a new approach to video-based augmented reality that avoids both requirements: it does not use any metric information about the calibration parameters of the camera or the 3D locations and dimensions of the environment's objects. The only requirement is the ability to track across frames at least four fiducial points that are specified by the user during system initialization and whose world coordinates are unknown. Our approach is based on the following observation: given a set of four or more noncoplanar 3D points, the projection of all points in the set can be computed as a linear combination of the projections of just four of the points. We exploit this observation by: tracking regions and color fiducial points at frame rate; and representing virtual objects in a non-Euclidean, affine frame of reference that allows their projection to be computed as a linear combination of the projection of the fiducial points. Experimental results on two augmented reality systems, one monitor-based and one head-mounted, demonstrate that the approach is readily implementable, imposes minimal computational and hardware requirements, and generates real-time and accurate video overlays even when the camera parameters vary dynamically     

Multimodal interaction with a wearable augmented reality system

An augmented reality system enhances a mobile user's situational awareness and provides new visualization functionality. The custom-built multimodal interface provides access to information encountered in urban environments. In this article, we detail our experiences with various input devices and modalities and discuss their advantages and drawbacks in the context of interaction tasks in mobile computing. We show how we integrated the input channels to use the modalities beneficially and how this enhances the interface's overall usability.     

增强现实系统软件平台的设计与实现

在对于一个增强现实系统的整体结构与各组成模块进行完整分析的基础之上,使用OpenCV、Coin3D和ARToolKit这3个软件开发包在Visual Studio 2003.net环境下开发了一个增强现实系统的软件平台.主要阐述了虚实环境的构建、三维注册、标志物检测、图像处理,视频融合等主要功能模块的实现原理与方法,最后给出了系统实际运行的效果.     

Mobile augmented reality based context-aware library management system

Mobile augmented reality has gained popularity in recent years due to the technological advances of smartphones and other mobile devices. One particular area in which mobile augmented reality is being used is library management. However, current mobile augmented reality solutions in this domain are lacking in context-awareness. It has been suggested in the literature that agent programming may be suitable at overcoming this problem, but little research has been conducted using modern mobile augmented reality applications with agents. This paper aims to bridge this gap through the development of an agent-based, mobile augmented reality prototype, titled Libagent. Libagent was subjected to five experiments to determine its suitability, efficiency, and accuracy for library management. The results of these experiments indicate that agent-based mobile augmented reality is a promising tool for context-aware library management.     

Mobile augmented reality for environmental monitoring

In response to dramatic changes in the environment, and supported by advances in wireless networking, pervasive sensor networks have become a common tool for environmental monitoring. However, tools for on-site visualization and interactive exploration of environmental data are still inadequate for domain experts. Current solutions are generally limited to tabular data, basic 2D plots, or standard 2D GIS tools designed for the desktop and not adapted to mobile use. In this paper, we introduce a novel augmented reality platform for 3D mobile visualization of environmental data. Following a user-centered design approach, we analyze processes, tasks, and requirements of on-site visualization tools for environmental experts. We present our multilayer infrastructure and the mobile augmented reality platform that leverages visualization of georeferenced sensor measurement and simulation data in a seamless integrated view of the environment.     

Live three-dimensional content for augmented reality

We describe an augmented reality system for superimposing three-dimensional (3-D) live content onto two-dimensional fiducial markers in the scene. In each frame, the Euclidean transformation between the marker and the camera is estimated. The equivalent virtual view of the live model is then generated and rendered into the scene at interactive speeds. The 3-D structure of the model is calculated using a fast shape-from-silhouette algorithm based on the outputs of 15 cameras surrounding the subject. The novel view is generated by projecting rays through each pixel of the desired image and intersecting them with the 3-D structure. Pixel color is estimated by taking a weighted sum of the colors of the projections of this 3-D point in nearby real camera images. Using this system, we capture live human models and present them via the augmented reality interface at a remote location. We can generate 384/spl times/288 pixel images of the models at 25 fps, with a latency of <100 ms. The result gives the strong impression that the model is a real 3-D part of the scene.     

Natural feature tracking for augmented reality

Natural scene features stabilize and extend the tracking range of augmented reality (AR) pose-tracking systems. We develop robust computer vision methods to detect and track natural features in video images. Point and region features are automatically and adaptively selected for properties that lead to robust tracking. A multistage tracking algorithm produces accurate motion estimates, and the entire system operates in a closed-loop that stabilizes its performance and accuracy. We present demonstrations of the benefits of using tracked natural features for AR applications that illustrate direct scene annotation, pose stabilization, and extendible tracking range. Our system represents a step toward integrating vision with graphics to produce robust wide-area augmented realities     

Real-time coherent stylization for augmented reality

This paper presents a new stylized augmented reality (AR) framework which can generate line drawing and abstracted shading styles. In comparison with the state-of-art work, our framework can significantly improve both the visual immersion of a single frame and the temporal coherence of augmented video streams in real time. In our framework, we first render virtual objects over the input camera images and then uniformly process the combined contents with stylization techniques. For generating line drawing stylization, we first propose a specially designed shading method to render the virtual objects, and then use an adapted Flow-based anisotropic Difference-of-Gaussion (FDoG) filter to yield the high-quality line drawing effect. For generating the abstracted stylization, a focus-guided diffusion filter and a soft color quantization operator are sequentially applied to the augmented image, and then the processed result is combined with the detected edges to produce the final abstraction effect. The presented algorithms are all sympathetic to highly parallel processing, allowing a real-time performance on contemporary graphics hardware.     

Information filtering for mobile augmented reality

The use of augmented reality (AR) techniques can revolutionize the way people interact with unfamiliar environments. By tracking the user's position and orientation, complicated spatial information can be registered against the real world. My colleagues and I are researching the problem of developing mobile AR systems to be worn by individual users operating in large, complicated environments such as cities. However, an urban environment is extremely complicated. It is populated by large numbers of buildings, each of which can have numerous facts stored about it. Therefore, it is easy for a user to experience information overload. This problem is illustrated. To minimize problems of information overload, we have begun to develop algorithms for information filtering. These tools automatically restrict the amount of information displayed     

Accurate overlaying for mobile augmented reality

Mobile augmented reality requires accurate alignment of virtual information with objects visible in the real world. We describe a system for mobile communications to be developed to meet these strict alignment criteria using a combination of computer vision, inertial tracking and low-latency rendering techniques. A prototype low-power and low-latency renderer using an off-the-shelf 3D card is discussed.     

Multi-cue hand detection and tracking for a head-mounted augmented reality system

With the recent developments in wearable augmented reality (AR), the role of natural human–computer interaction is becoming more important. Utilization of auxiliary hardware for interaction introduces extra complexity, weight and cost to wearable AR systems and natural means of interaction such as gestures are therefore more desirable. In this paper, we present a novel multi-cue hand detection and tracking method for head-mounted AR systems which combines depth, color, intensity and curvilinearity. The combination of different cues increases the detection rate, eliminates the background regions and therefore increases the tracking performance under challenging conditions. Detected hand positions and the trajectories are used to perform actions such as click, select, etc. Moreover, the 6 DOF poses of the hands are calculated by approximating the segmented regions with planes in order to render a planar menu (interface) around the hand and use the hand as a planar selection tool. The proposed system is tested on different scenarios (including markers for reference) and the results show that our system can detect and track the hands successfully in challenging conditions such as cluttered and dynamic environments and illumination variance. The proposed hand tracker outperforms other well-known hand trackers under these conditions.