Improving the Performance of K-Means for Color Quantization

Color quantization is an important operation with many applications in graphics and image processing. Most quantization methods are essentially based on data clustering algorithms. However, despite its popularity as a general purpose clustering algorithm, k-means has not received much respect in the color quantization literature because of its high computational requirements and sensitivity to initialization. In this paper, we investigate the performance of k-means as a color quantizer. We implement fast and exact variants of k-means with several initialization schemes and then compare the resulting quantizers to some of the most popular quantizers in the literature. Experiments on a diverse set of images demonstrate that an efficient implementation of k-means with an appropriate initialization strategy can in fact serve as a very effective color quantizer.Comment: 26 pages, 4 figures, 13 table

Tracking In A Multi-User Augmented Reality System

We present a tracking system integrating both optical and magnetic tracking which runs on low-cost hardware. This tracking system is part of the "Studierstube", a new multi-user augmented reality system. On the one hand, two independently running tracking systems are integrated to complement each other, on the other hand by using only parts of two independent tracking systems we can obtain a unique result which is superior to the complete result of any one of the two systems alone. Keywords: augmented reality, tracking, registration, integration of optical and magnetic tracking 1 Introduction In augmented reality applications, precise registration is important: If the position or orientation of the user cannot be determined precisely, the augmentation will be unsatisfactory: Virtual Objects will be displaced, or even worse, they will freely float around in the space surrounding the user. Thus, precise registration is needed to avoid these symptoms. Further stress on precise registr..

A design and evaluation framework for a tele-immersive mixed reality platform

Tele-immersive, mixed reality interactive systems bring remote users together to share a common experience in an environment that synthesizes aspects of the real and virtual worlds. The 3D-LIVE platform is an example of one such system that synthesizes 3D models, audio, motion capture and activity from a number of geographically separated sources into a single gaming environment to support a variety of sports based activities. The design and evaluation of such systems is challenging since factors relating to the technical quality of service (QoS) and quality of experience (QoE) are difficult to identify and measure. In this paper we present a novel QoS/QoE model and evaluation methodology that is being used in the development and testing of the 3D-LIVE mixed reality platform. Our initial results provide some insights into the quality of user experience (UX) we observed from users interacting with 3D-LIVE and are evaluated in the light of QoS data captured. We conclude by discussing the impact of these findings on future platform developments

The evaluation of tree performance after transplanting

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