In 1997, Azuma published a survey on augmented reality (AR). Our goal is to complement, rather than replace, the original survey by presenting representative examples of the new advances. We refer one to the original survey for descriptions of potential applications (such as medical visualization, maintenance and repair of complex equipment, annotation, and path planning); summaries of AR system characteristics (such as the advantages and disadvantages of optical and video approaches to blending virtual and real, problems in display focus and contrast, and system portability); and an introduction to the crucial problem of registration, including sources of registration error and error-reduction strategies.

https://www.cc.gatech.edu/~blair/papers/ARsurveyCGA.pdf

Recent advances in augmented reality

An introduction to the Kalman filter

In 1960, R.E. Kalman published his famous paper describing a recursive solution to the discrete-data linear filtering problem. Since that time, due in large part to advances in digital computing, the Kalman filter has been the subject of extensive research and application, particularly in the area of autonomous or assisted navigation. The Kalman filter is a set of mathematical equations that provides an efficient computational (recursive) means to estimate the state of a process, in a way that minimizes the mean of the squared error. The filter is very powerful in several aspects: it supports estimations of past, present, and even future states, and it can do so even when the precise nature of the modeled system is unknown. The purpose of this paper is to provide a practical introduction to the discrete Kalman filter. This introduction includes a description and some discussion of the basic discrete Kalman filter, a derivation, description and some discussion of the extended Kalman filter, and a relatively simple (tangible) example with real numbers & results.

/pdf/an-introduction-to-the-kalman-filter-4na56gymup.pdf

An Introduction to the Kalman Filter

We describe an augmented reality conferencing system which uses the overlay of virtual images on the real world. Remote collaborators are represented on virtual monitors which can be freely positioned about a user in space. Users can collaboratively view and interact with virtual objects using a shared virtual whiteboard. This is possible through precise virtual image registration using fast and accurate computer vision techniques and head mounted display (HMD) calibration. We propose a method for tracking fiducial markers and a calibration method for optical see-through HMD based on the marker tracking.

/pdf/marker-tracking-and-hmd-calibration-for-a-video-based-44oiw0a2ha.pdf

Marker tracking and HMD calibration for a video-based augmented reality conferencing system

Automatic generation and detection of highly reliable fiducial markers under occlusion

"Studierstube" - An Environment for Collaboration in Augmented Reality

We present a strategy for rendering in distributed virtual environments. A geometry database is maintained by a server, while users invoke individual clients to interact with the environment. Instead of downloading a complete copy of the geometry data, the data is distributed on demand, thus gaining signifcant savings in network bandwidth. Our strategy combines several techniques, including levels of detail, progressive refinement and graceful degradation to deliver the data “just in time” over the network to the rendering process. The method allows operate on a tight resource budget, which important if attempting to use low cost systems for virtual reality applications.

/pdf/demand-driven-geometry-transmission-for-distributed-virtual-52z4h01x0q.pdf

Demand‐Driven Geometry Transmission for Distributed Virtual Environments

https://hal.inria.fr/inria-00537515/document

Occlusion in Collaborative Augmented Environments

Augmented environments superimpose computer graphics on the real world. Such augmented environments are well suited for collaboration of multiple users. To improve the quality and consistency of the augmentation, the occlusion of real objects by computer-generated objects and vice versa has to be implemented. We present methods how this can be done for a tracked user’s body and other real objects and how irritating artifacts due to misalignments can be reduced. Our method is based on simulating the occlusion of virtual objects by a representation of the user modeled as kinematic chains of articulated solids. Registration and modeling errors of this model are being reduced by smoothing the border between virtual world and occluding real object. An implementation in our augmented environment and the resulting improvements are presented.

Occlusion in Collaborative Augmented Environments.

This paper introduces the 3D Measurement and Virtual Reconstruction of Ancient Lost Worlds of Europe system (3D MURALE). It consists of a set of tools for recording, reconstructing, encoding, visualising and database searching/querying that operate on buildings, building parts, statues, statue parts, pottery, stratigraphy, terrain geometry and texture and material texture. The tools are loosely linked together by a common database on which they all have the facility to store and access data. The paper describes the overall architecture of the 3D MURALE system and then briefly describes the functionality of the tools provided by the project. The paper compares the multimedia studio architecture adopted in this project with other multimedia studio architectures.

/pdf/3d-murale-a-multimedia-system-for-archaeology-3vynrq3ny9.pdf

Michael Gervautz

Papers

"Studierstube" - An Environment for Collaboration in Augmented Reality

Demand‐Driven Geometry Transmission for Distributed Virtual Environments

Occlusion in Collaborative Augmented Environments

Occlusion in Collaborative Augmented Environments.

3D MURALE: a multimedia system for archaeology