卡通风格增强现实系统

增强现实技术将计算机生成的虚拟物体叠加到真实场景中.在传统的AR系统中,虚拟物体和真实场景视觉上存在较为明显的差异,达不到虚拟物体和真实场景无缝结合的要求.本文将增强现实技术与非真实感的绘制技术有机的结合起来,减小这种视觉差异,研究并实现了卡通风格的增强现实系统.     

基于增强现实的虚拟实景空间的研究与实现

增强现实可以把计算机产生的虚拟物体或其他信息合成到用户看到的真实场景中．本文将增强现实技术与基于图像的绘制技术有机的结合起来，研究并实现了一个基于增强现实技术的虚拟实景空间系统．首先介绍了虚拟实景空间的构造，然后着重探讨了虚拟物体与实景空间的合成方法，主要解决合成中的几何一致性和光照一致性问题。     

基于ARToolKit工具的增强现实交互操作研究

增强现实是把计算机生成的虚拟图像或其它信息叠加到用户所看到的真实世界中的一种技术。ARToolKit为增强现实技术的应用提供了一种方便快捷的开发工具,但多针对于浏览展示方面。本文在ARToolKit工具下针对AVI录像文件进行增强现实的应用开发,增加了用户和现实以及虚拟物体的交互操作,通过计算机视觉的方法着重解决把虚拟物体放置到用户在视频帧上指定的点。这些将为用户使用增强现实技术进行设计和规划提供方便。     

移动增强现实关键技术及研究进展

移动增强现实的概念和现实意义增强现实是随着计算机图形技术、可视化技术以及光电成像技术等一系列技术的发展在近年出现的,虚拟现实营造一个和用户周围环境完全不同的由计算机生成的虚拟场景,而增强现实则是把计算机生成的虚拟物体或文字信息叠加到真实的环境中,增强现实在虚拟环境和真实环境之间搭起了一个桥梁。     

基于iPhone的城市街道增强现实系统的设计与研究

该文介绍了增强现实技术及其在城市街道增强现实系统中的典型应用。可以通过计算机技术生成与真实场景相关但现实中并不直接可见的虚拟物体或信息,并将虚拟物体或信息以合适的角度摆放到真实场景中恰当的位置,以实现对现实的增强,利用iPhone智能手机IOS等开放平台,为智能手机用户搜索当前位置附近的感兴趣地点,并获得直观快速的良好用户体验。     

基于iPhone的城市街道增强现实系统的设计与研究

该文介绍了增强现实技术及其在城市街道增强现实系统中的典型应用。可以通过计算机技术生成与真实场景相关但现实中并不直接可见的虚拟物体或信息,并将虚拟物体或信息以合适的角度摆放到真实场景中恰当的位置,以实现对现实的增强,利用iPhone智能手机IOS等开放平台,为智能手机用户搜索当前位置附近的感兴趣地点,并获得直观快速的良好用户体验。     

基于增强现实的虚拟实景空间漫游机制研究与实现

增强现实技术可以把计算机产生的虚拟物体或其它信息合成到用户看到的真实场景中.将增强现实技术与基于图像的绘制技术有机的结合起来,介绍了虚拟实景空间的构造,探讨了虚拟物体与实景空间的合成方法,给出了一种在虚拟实景空间中漫游的机制及其实现方法,综合考虑了机制的复杂度和漫游的自由度,在两者之间取得了平衡,该方法具有较好的实用性.     

基于视觉的增强现实运动跟踪算法

增强现实系统不仅具有虚拟现实的特点同时具有虚实结合的新特性，为实现虚拟物体与真实物体间的完善结合，必须实时地动态跟踪摄像与真实物体间的相对位置和方向，建立观测模,墼是而通过动态三维显示技术迅速地将虚拟物体添加到真实物体之上，然而目前大多数增强现实系统的注册对象均匀静物体，运动物体的注册跟踪尚很少有人涉足。该算法通过标志点的光流场估计真实环境中运动物体的运动参数，根据透视投影原理和刚体的运动特性确定摄像机与运动物体间的相对位置和方向，实现增强现实系统的运动目标跟踪注册。该算法构架简单、实时性强，易于实现，扩展了增强现实系统的应用范围。     

用于增强现实的光照估计研究综述

增强现实技术将计算机生成的虚拟物体实时叠加到用户周围的真实场景中,虚拟物体与真实环境拥有一致的光照效果是该技术的难点之一.光照一致性研究包括光照估计、材质表面反射属性估计以及真实感渲染等内容,其中光照估计是光照一致性的先决条件,结合材质表面反射属性可以保证虚实物体一致的光照渲染效果.文中概述了增强现实中光照一致性研究的最新进展,通过分析现有技术的优缺点阐述了当前光照估计研究所面临的主要挑战,同时展望了该领域未来的发展方向.     

水彩画风格实时增强现实技术

在传统的AR系统中,虚拟物体和真实场景在视觉上存在较为明显的差异,达不到虚拟物体和真实场景无缝结合的要求。将增强现实技术与NPR有机地结合起来,减小这种视觉差异,研究并实现了水彩画风格的增强现实系统。     

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     

视触觉融合的增强现实三维注册方法

增强现实技术是近年来人机交互领域的研究热点。在增强现实环境下加入触觉感知,可使用户在真实场景中看到并感知到虚拟对象。为了实现增强现实环境下与虚拟对象之间更加自然的交互,提出一种视触觉融合的三维注册方法。基于图像视觉技术获得三维注册矩阵;借助空间转换关系求解出触觉空间与图像空间的转换关系;结合两者与摄像头空间的关系实现视触觉融合的增强现实交互场景。为验证该方法的有效性,设计了一个基于视触觉增强现实的组装机器人项目。用户可触摸并移动真实环境中的机器人零件,还能在触摸时感受到反馈力,使交互更具真实感。     

Natural perception in dynamic stereoscopic augmented reality environments

Notwithstanding the recent diffusion of the stereoscopic 3D technologies for the development of powerful human computer interaction systems based on augmented reality environment, with the conventional approaches an observer freely moving in front of a 3D display could experience a misperception of the depth and of the shape of virtual objects. Such distortions can cause eye fatigue and stress for entertainment applications, and they can have serious consequences in scientific and medical fields, where a veridical perception of the scene layout is required. We propose a novel technique to obtain augmented reality systems capable to correctly render 3D virtual objects to an observer that changes his/her position in the real world and acts in the virtual scenario. By tracking the positions of the observer’s eyes, the proposed technique generates the correct virtual view points through asymmetric frustums, thus obtaining the correct left and right projections on the screen. The natural perception of the scene layout is assessed through three experimental sessions with several observers.     

Harmonic rendering for visual coherence on mobile outdoor AR environment

Rapid developments in augmented reality (AR) and related technologies have led to increasing interest in immersive content. AR environments are created by combining virtual 3D models with a real-world video background. It is important to merge these two worlds seamlessly if users are to enjoy AR applications, but, all too often, the illumination and shading of virtual objects is not consider the real world lighting condition or does not match that of nearby real objects. In addition, visual artifacts produced when blending real and virtual objects further limit realism. In this paper, we propose a harmonic rendering technique that minimizes the visual discrepancy between the real and virtual environments to maintain visual coherence in outdoor AR. To do this, we introduce a method of estimating and approximating the Sun’s position and the sunlight direction to estimate the real sunlight intensity, as this is the most significant illumination source in outdoor AR and it provides a more realistic lighting environment for such content, reducing the mismatch between real and virtual objects.

     

A study on differences in human perception between a real and an AR scene viewed in an OST‐HMD

With the recent growth in the development of augmented reality (AR) technologies, it is becoming important to study human perception of AR scenes. In order to detect whether users will suffer more from visual and operator fatigue when watching virtual objects through optical see‐through head‐mounted displays (OST‐HMDs), compared with watching real objects in the real world, we propose a comparative experiment including a virtual magic cube task and a real magic cube task. The scores of the subjective questionnaires (SQ) and the values of the critical flicker frequency (CFF) were obtained from 18 participants. In our study, we use several electrooculogram (EOG) and heart rate variability (HRV) measures as objective indicators of visual and operator fatigue. Statistical analyses were performed to deal with the subjective and objective indicators in the two tasks. Our results suggest that participants were very likely to suffer more from visual and operator fatigue when watching virtual objects presented by the OST‐HMD. In addition, the present study provides hints that HRV and EOG measures could be used to explore how visual and operator fatigue are induced by AR content. Finally, three novel HRV measures are proposed to be used as potential indicators of operator fatigue.     

Modelling and design of an augmented reality differential drive mobility aid in an enabled environment

In this paper the authors discuss the modelling and design of an augmented reality platform for disabled wheeled mobility studies. This design consists of a virtual environment with two degrees of freedom motion platform and integrated ground contact force feedback. Differential drive mobility users continue to be in touch with reality on their own mobility aid while interacting with virtual objects. The major domain related to the differential drive mobility of the disabled members of society which coincides with the use of manual wheelchairs, electric wheelchairs and mobility scooters. In order to account for environmental and dynamic effects, the wheeled mobility user needs to map the intended trajectory into the virtual world. Motion and inertia force feedback produced on the augmented simulator give the users a haptic sensory stimulus input regarding spatial movement and ground contact forces. The main objective is to model and design an augmented reality platform with real world kinematic and dynamic properties to place a wheeled mobility user closer to real world encounters. The use of the designed augmented reality platform will be beneficial to disabled wheeled mobility users in need of occupational therapist training and evaluation.     

Interactive 3D content insertion in images for multimedia applications

This article addresses the problem of creating interactive mixed reality applications where virtual objects interact in images of real world scenarios. This is relevant to create games and architectural or space planning applications that interact with visual elements in the images such as walls, floors and empty spaces. These scenarios are intended to be captured by the users with regular cameras or using previously taken photographs. Introducing virtual objects in photographs presents several challenges, such as pose estimation and the creation of a visually correct interaction between virtual objects and the boundaries of the scene. The two main research questions addressed in this article include, the study of the feasibility of creating interactive augmented reality (AR) applications where virtual objects interact in a real world scenario using the image detected high-level features and, also, verifying if untrained users are capable and motivated enough to perform AR initialization steps. The proposed system detects the scene automatically from an image with additional features obtained using basic annotations from the user. This operation is significantly simple to accommodate the needs of non-expert users. The system analyzes one or more photos captured by the user and detects high-level features such as vanishing points, floor and scene orientation. Using these features it will be possible to create mixed and augmented reality applications where the user interactively introduces virtual objects that blend with the picture in real time and respond to the physical environment. To validate the solution several system tests are described and compared using available external image datasets.