Tracking of industrial objects by using CAD models

In this paper we present a model-based approach for real-time camera pose estimation in industrial scenarios. The line model which is used for tracking is generated by rendering a polygonal model and extracting contours out of the rendered scene. By un-projecting a point on the contour with the depth value stored in the z-buffer, the 3D coordinates of the contour can be calculated. For establishing 2D/3D correspondences the 3D control points on the contour are projected into the image and a perpendicular search for gradient maxima for every point on the contour is performed. Multiple hypotheses of 2D image points corresponding to a 3D control point make the pose estimation robust against ambiguous edges in the image.

3-D Audio in Mobile Communication Devices: Methods for Mobile Head-Tracking

Future generations of mobile communication devices will serve more and more as multimedia platforms capable of reproducing high quality audio. In order to achieve a 3-D sound perception the reproduction quality of audio via headphones can be significantly increased by applying binaural technology. To be independent of individual head-related transfer functions (HRTFs) and to guarantee a good performance for all listeners, an adaptation of the synthesized sound field to the listener's head movements is required. In this article several methods of head-tracking for mobile communication devices are presented and compared. A system for testing the identified methods is set up and experiments are performed to evaluate the prosand cons of each method. The implementation of such a device in a 3-D audio system is described and applications making use of such a system are identified and discussed.

The Impact of Western Social Workers in Romania - a Fine Line between Empowerment and Disempowerment

Ideally the social work profession promotes social change, problem solving in human relationships and the empowerment and liberation of people to enhance their well-being (IFSW 2004). The social work practice, however, often proves to be different. Social workers are always in the danger to make decisions for their clients or define problems according to their own interpretation and world view. In quite a number of cases, the consequence of such a social work practice is that the clients feel disempowered rather than empowered. This dilemma is multiplying when western social workers get involved in developing countries. The potential that intervention, with the intention to empower and liberate the people, turns into disempowerment is tremendously higher because of the differences in tradition, culture and society, on the one side and the power imbalance between the ‘West’ and the ‘Rest’ on the other side. Especially in developing countries, where the vast majority of people live in poverty, many Western social workers come with a lot of sympathy and the idea to help the poor and to change the world. An example is Romania. After the collapse of communism in 1989, Romania was an economically, politically and socially devastated country. The pictures of the orphanages shocked the western world. As a result many Non-Governmental Organisations (NGOs), churches and individuals were bringing humanitarian goods to Romania in order to alleviate the misery of the Romanian people and especially the children. Since then, important changes in all areas of life have occurred, mostly with foreign financial aid and support. At the political level, democratic institutions were established, a liberal market economy was launched and laws were adapted to western standards regarding the accession into the European Union and the NATO. The western world has left its marks also at the grassroots level in form of NGOs or social service agencies established through western grants and individuals. Above and beyond, the presence of western goods and investment in Romania is omnipresent. This reflects a newly-gained freedom and prosperity - Romania profits certainly from these changes. But this is only one side of the medal, as the effect of westernisation contradicts with the Romanian reality and overruns many deep-rooted traditions, thus the majority of people. Moreover, only a small percentage of the population has access to this western world. Western concepts, procedures or interpretations are often highly differing from the Romanian tradition, history and culture. Nevertheless, western ideas seem to dominate the transition in many areas of daily life in Romania. A closer look reveals that many changes take place due to pressure of western governments and are conditioned to financial support. The dialectic relationship between the need for foreign aid and the implementation becomes very obvious in Romania and often leads, despite the substantial benefits, to unpredictable and rather negative side-effects, at a political, social, cultural, ecological and/or economic level. This reality is a huge dilemma for all those involved, as there is a fine line between empowering and disempowering action. It is beyond the scope of this journal to discuss the dilemma posed by Western involvement at all levels; therefore this article focuses on the impact of Western social workers in Romania. The first part consists of a short introduction to social work in Romania, followed by the discussion about the dilemma posed by the structure of project of international social work and the organisation of private social service agencies. Thirdly the experiences of Romanian staff with Western social workers are presented and then discussed with regard to turning disempowering tendencies of Western social workers into empowerment.

Automatic Data Normalization and Parameterization for Optical Motion Tracking

Methods for optical motion capture often require timeconsuming manual processing before the data can be used for subsequent tasks such as retargeting or character animation. These processing steps restrict the applicability of motion capturing especially for dynamic VR-environments with real time requirements. To solve these problems, we present two additional, fast and automatic processing stages based on our motion capture pipeline presented in [HSK05]. A normalization step aligns the recorded coordinate systems with the skeleton structure to yield a common and intuitive data basis across different recording sessions. A second step computes a parameterization based on automatically extracted main movement axes to generate a compact motion description. Our method does not restrict the placement of marker bodies nor the recording setup, and only requires a short calibration phase.

Head Tracking Based Avatar Control for Virtual Environment Teamwork Training

Virtual environments (VE) are gaining in popularity and are increasingly used for teamwork training purposes, e.g., for medical teams. One shortcoming of modern VEs is that nonverbal communication channels, essential for teamwork, are not supported well. We address this issue by using an inexpensive webcam to track the user's head. This tracking information is used to control the head movement of the user's avatar, thereby conveying head gestures and adding a nonverbal communication channel. We conducted a user study investigating the influence of head tracking based avatar control on the perceived realism of the VE and on the performance of a surgical teamwork training scenario. Our results show that head tracking positively influences the perceived realism of the VE and the communication, but has no major influence on the training outcome.

A user supported object tracking framework for interactive video production

We present a user supported tracking framework that combines automatic tracking with extended user input to create error free tracking results that are suitable for interactive video production. The goal of our approach is to keep the necessary user input as small as possible. In our framework, the user can select between different tracking algorithms - existing ones and new ones that are described in this paper. Furthermore, the user can automatically fuse the results of different tracking algorithms with our robust fusion approach. The tracked object can be marked in more than one frame, which can significantly improve the tracking result. After tracking, the user can validate the results in an easy way, thanks to the support of a powerful interpolation technique. The tracking results are iteratively improved until the complete track has been found. After the iterative editing process the tracking result of each object is stored in an interactive video file that can be loaded by our player for interactive videos.

Application of Time-Delay Estimation to Mixed Reality Multisensor Tracking

Spatial tracking is one of the most challenging and important parts of Mixed Reality environments. Many applications, especially in the domain of Augmented Reality, rely on the fusion of several tracking systems in order to optimize the overall performance. While the topic of spatial tracking sensor fusion has already seen considerable interest, most results only deal with the integration of carefully arranged setups as opposed to dynamic sensor fusion setups. A crucial prerequisite for correct sensor fusion is the temporal alignment of the tracking data from several sensors. Tracking sensors are typically encountered in Mixed Reality applications, are generally not synchronized. We present a general method to calibrate the temporal offset between different sensors by the Time Delay Estimation method which can be used to perform on-line temporal calibration. By applying Time Delay Estimation on the tracking data, we show that the temporal offset between generic Mixed Reality spatial tracking sensors can be calibrated. To show the correctness and the feasibility of this approach, we have examined different variations of our method and evaluated various combinations of tracking sensors. We furthermore integrated this time synchronization method into our UBITRACK Mixed Reality tracking framework to provide facilities for calibration and real-time data alignment.

EU Data Protection Law and Targeted Advertising: Consent and the Cookie Monster - Tracking the crumbs of online user behaviour

This article provides a holistic legal analysis of the use of cookies in Online Behavioural Advertising. The current EU legislative framework is outlined in detail, and the legal obligations are examined. Consent and the debates surrounding its implementation form a large portion of the analysis. The article outlines the current difficulties associated with the reliance on this requirement as a condition for the placing and accessing of cookies. Alternatives to this approach are explored, and the implementation of solutions based on the application of the Privacy by Design and Privacy by Default concepts are presented. This discussion involves an analysis of the use of code and, therefore, product architecture to ensure adequate protections.