Innovative geometric pose reconstruction for marker-based single camera tracking.
ABSTRACT Mobile augmented reality applications are in need of tracking systems which can be wearable and do not cause a high processing load, while still offering reasonable performance, robustness and accuracy. The motivation to develop yet another tracking algorithm is two-fold. Most of the existing approaches use classical optimization techniques such as the Gauss-Newton method. However, since those algorithms were developed to address general optimization problems, they do not fully exploit the structure of the pose estimation problem with its geometric constraint targets. Also, mixed reality applications demand that pose estimation be not only accurate but also robust and computationally efficient. Hence there is a need for algorithms that are as accurate as classical algorithms, yet are also globally convergent and fast enough for real-time applications. In this paper we introduce a new iterative geometric method for pose estimation from four co-planar points and we present the current status of PTrack, an infrared marker-based single camera tracking system benefiting from this approach. Our novel pose estimation algorithm identifies possible labels composed of retro-reflective markers in a 2D post-processing using a divide-and-conquer strategy to segment the camera's image space and attempts an iterative geometric D reconstruction of position and orientation in camera space. Tracking results are made available to applications through OpenTracker [OpenTracker 2006] framework. To analyse tracking accuracy and precision, we built a generic test-bed and compared PTrack to ARToolKit [Kato and Billinghurst 1999; Kato et al. 2000], one of the most wide-spread low-cost tracking solutions. Results show that our tracking system achieves competitive accuracy levels better than ARToolKit and close to commercial systems, while being highly stable and affordable.
- SourceAvailable from: Maurizio Muzzupappa
Conference Paper: Real Time Tracking using Stereo Vision for Augmented Reality20th International Congress of Graphic Engeeniering, Valencia, 4-6 June; 01/2008
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ABSTRACT: In this paper, we describe a novel algorithm to group, label, identify and perform optical tracking of marker sets, which are grouped into two specific configurations, and whose projective invariant properties will allow obtaining a unique identification for each predefined marker pattern. These configurations are formed by 4 collinear and 5 coplanar markers. This unique identification is used to correctly recognize various and different marker patterns inside the same tracking area, in real time. The algorithm only needs image coordinates of markers to perform the identification of marker patterns. For grouping the dispersed markers that appear in the image, the algorithm uses a "divide and conquer" strategy to segment the image and give some neighborhood reference among markers.Advances in Visual Computing, Third International Symposium, ISVC 2007, Lake Tahoe, NV, USA, November 26-28, 2007, Proceedings, Part I; 01/2007
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ABSTRACT: We present the work on a simulator of construction machinery developed to train workers in their safe use. The simulation setup consists of a real versatile cabin placed on a motion platform in order to provide a realistic interaction with the system and a stereoscopic augmented reality system for visualization. We present some insights into the mixed reality setup we used for complex construction machines and discuss the interaction and usability problems that have arisen during its development and testing. Visualization has been implemented as a chroma-key-based mixed reality system, which combines the 3D virtual environment, the real cabin interior, and some superimposed messages to the user. As a result of our experience, we describe the main problems encountered from a usability and ergonomics point of view.Ergonomics and Health Aspects of Work with Computers, International Conference, EHAWC 2007, Held as Part of HCI International 2007, Beijing, China, July 22-27, 2007, Proceedings; 01/2007