Mark Ollila

Face to face collaborative AR on mobile phones

Mobile phones are an ideal platform for augmented reality. In this paper we describe how they also can be used to support face to face collaborative AR applications. We have created a custom port of the ARToolKit library to the Symbian mobile phone operating system and then developed a sample collaborative AR game based on this. We describe the game in detail and user feedback from people who have played it. We also provide general design guidelines that could be useful for others who are developing mobile phone collaborative AR applications.

UMAR: Ubiquitous Mobile Augmented Reality

In this paper we discuss the prospects of using marker based Augmented Reality for context aware applications on mobile phones. We also present the UMAR, a conceptual framework for developing Ubiquitous Mobile Augmented Reality applications which consists of research areas identified as relevant for successfully bridging the physical world and the digital domain using Mobile Augmented Reality. A step towards this we have successfully ported the ARToolkit to consumer mobile phones running on the Symbian platform and present results around this. We also present three sample applications based on UMAR and future case study work planned.

Virtual object manipulation using a mobile phone

Augmented Reality (AR) on mobile phones has reached a level of maturity where it can be used as a tool for 3D object manipulation. In this paper we look at user interface issues where an AR enabled mobile phone acts as an interaction device. We discuss how traditional 3D manipulation techniques apply to this new platform. The high tangibility of the device and its button interface makes it interesting to compare manipulation techniques. We describe AR manipulation techniques we have implemented on a mobile phone and present a small pilot study evaluating these methods.

Eurographics Symposium on Rendering

The 2004 Eurographics Symposium on Rendering took place in Norrköping, Sweden, 21–23 June 2004. The program co-chairs were Henrik Wann Jensen and Alexander Keller. The local organizers were Mark Ollila, Ken Museth, Anders Ynnerman and other members of the Department of Science and Technology at Linköping University. The symposium is the premiere forum and resource dedicated to rendering research. It is the 15 in a sequence of 13 Eurographics Workshops on Rendering and one Eurographics Symposium on Rendering. The Symposium was held in cooperation with ACM SIGGRAPH, and was sponsored by ATI Technologies Ltd and the Norrköping Municipality.

Mobile phone based AR scene assembly

In this paper we describe a mobile phone based Augmented Reality application for 3D scene assembly. Augmented Reality on mobile phones extends the interaction capabilities on such handheld devices. It adds a 6 DOF isomorphic interaction technique for manipulating 3D content. We give details of an application that we believe to be the first where 3D content can be manipulated using both the movement of a camera tracked mobile phone and a traditional button interface as input for transformations. By centering the scene in a tangible marker space in front of the phone we provide a mean for bimanual interaction. We describe the implementation, the interaction techniques we have developed and initial user response to trying the application.

AR tennis

AR Tennis is the first example of a face to face collaborative AR application developed for mobile phones. In this application two players sit across a table from each other with a piece of paper between them that has a set of ARToolKit markers drawn on it. Computer vision techniques are used to track the phone position relative to the markers. When the player points the phone camera at the markers they see a virtual tennis court overlaid on live video of the real world.

A Real Time Light Probe

We present a novel system capable of capturing high dynamic range (HDR) Light Probes at video speed. Each Light Probe frame is built from an individual full set of exposures, all of which are captured within the frame time. The exposures are processed and assembled into a mantissa-exponent representation image within the camera unit before output, and then streamed to a standard PC. As an example, the system is capable of capturing Light Probe Images with a resolution of 512x512 pixels using a set of 10 exposures covering 15 f-stops at a frame rate of up to 25 final HDR frames per second. The system is built around commercial special-purpose camera hardware with on-chip programmable image processing logic and tightly integrated frame buffer memory, and the algorithm is implemented as custom downloadable microcode software.

Interactive collaborative scene assembly using AR on mobile phones

In this paper we present and evaluate a platform for interactive collaborative face-to-face Augmented Reality using a distributed scene graph on mobile phones. The results of individual actions are viewed on the screen in real-time on every connected phone. We show how multiple collaborators can use consumer mobile camera phones to furnish a room together in an Augmented Reality environment. We have also presented a user case study to investigate how untrained users adopt this novel technology and to study the collaboration between multiple users. The platform is totally independent of a PC server though it is possible to connect a PC client to be used for high quality visualization on a big screen device such as a projector or a plasma display.

Augmented reality on smartphones

Smartphones with built-in cameras are becoming ubiquitous. These devices couple a camera with communication and processing units and are increasingly capable of 3D rendering. We have conducted camera sensitivity test on current smartphones to evaluate in what extent they can be used for augmented reality (AR) using optical tracking.

Real-time image based lighting in software using HDR panoramas

We present a system allowing real-time image based lighting based on HDR panoramic images [Debevec 1998]. The system performs time-consuming diffuse light calculations in a pre-processing step, which is key to attaining interactivity. The real-time subsystem processes an image based lighting model in software, which would be simple to implement in hardware. Rendering is handled by OpenGL, but could be substituted for another graphics API, should there be such a need. Applications for the technique presented are discussed, and includes methods for realistic outdoor lighting. The system architecture is outlined, describing the algorithms used. Lastly, the ideas for future work that arose during the project are discussed