| 1. |
- Abedan Kondori, Farid, 1983-
(författare)
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Bring Your Body into Action : Body Gesture Detection, Tracking, and Analysis for Natural Interaction
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Due to the large influx of computers in our daily lives, human-computer interaction has become crucially important. For a long time, focusing on what users need has been critical for designing interaction methods. However, new perspective tends to extend this attitude to encompass how human desires, interests, and ambitions can be met and supported. This implies that the way we interact with computers should be revisited. Centralizing human values rather than user needs is of the utmost importance for providing new interaction techniques. These values drive our decisions and actions, and are essential to what makes us human. This motivated us to introduce new interaction methods that will support human values, particularly human well-being.The aim of this thesis is to design new interaction methods that will empower human to have a healthy, intuitive, and pleasurable interaction with tomorrow’s digital world. In order to achieve this aim, this research is concerned with developing theories and techniques for exploring interaction methods beyond keyboard and mouse, utilizing human body. Therefore, this thesis addresses a very fundamental problem, human motion analysis.Technical contributions of this thesis introduce computer vision-based, marker-less systems to estimate and analyze body motion. The main focus of this research work is on head and hand motion analysis due to the fact that they are the most frequently used body parts for interacting with computers. This thesis gives an insight into the technical challenges and provides new perspectives and robust techniques for solving the problem.
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| 2. |
- Abedan Kondori, Farid, 1983-
(författare)
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Human Motion Analysis for Creating Immersive Experiences
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- From an early age, people display the ability to quickly and effortlessly interpret the orientation and movement of human body parts, thereby allowing one to infer the intentions of others who are nearby and to comprehend an important nonverbal form of communication. The ease with which one accomplishes this task belies the difficulty of a problem that has challenged computational systems for decades, human motion analysis. Technological developments over years have resulted into many systems for measuring body segment positions and angles between segments. In these systems human body is typically considered as a system of rigid links connected by joints. The motion is estimated by the use of measurements from mechanical, optical, magnetic, or inertial trackers. Among all kinds of sensors, optical sensing encompasses a large and varying collection of technologies. In a computer vision context, human motion analysis is a topic that studies methods and applications in which two or more consecutive images from an image sequences, e.g. captured by a video camera, are processed to produce information based on the apparent human body motion in the images. Many different disciplines employ motion analysis systems to capture movement and posture of human body for applications such as medical diagnostics, virtual reality, human-computer interaction etc. This thesis gives an insight into the state of the art human motion analysissystems, and provides new methods for capturing human motion.
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| 3. |
- Fahlquist, Karin
(författare)
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Creating new experience for zoo visitors by using media techniques
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In 2008, the EU project “Digital Djurpark” (Digital Zoo) started as a cooperation between the digital media lab at the department of Applied Physics and Electronics (TFE) at Umeå University and Lycksele Zoo. The technology behind the Digital Zoo project is a wireless sensor network that is placed in the park. This wireless sensor network collects information from the park and is able to save data for the future but also send live data outside the park. The idea behind the project Digital Zoo was to give zoo-visitors new experiences during their visit and let them be able to interact with the zoo and to give the visitor a chance to get to know the animals in a more personal way.The objective of this thesis is to create new experiences by using media techniques and the application environment is Digital Zoo. The work can be seen as applied research because of the focus on an actual case, Digital Zoo. The major scientific challenge with this work is to use media techniques so the experience for the visitor feels like a new experience. The overall research question is: How is it possible to give the zoo visitors new experience by using media techniques? This overall question is broken down into three sub-questions: (1) How is it possible to let the visitors feel involved in the experience by using media techniques?; (2) How is it possible to adapt the experience to the visitor by using media techniques?; (3) How is it possible to integrate the experience in both the digital and the physical world by using media techniques?To create new experience for a zoo visitor it is necessary to understand the visitor better, therefore this work become interdisciplinary, touching on aspects and approaches such as interaction, media technology, social science, and marketing. To investigate different ways to enhance the visitors experience regarding the Digital Zoo interaction, the following research methods were used: case study, surveys, interviews, prototyping, and user tests. Participants in these studies were representatives from Swedish zoos, visitor in Lycksele Zoo, and children from school classes in Umeå.It is of importance to recognize that this work will not give a general result on how to create experiences for users. However, since this work has been based on a real case, Digital Zoo, it is most certainly possible to find results that can be applied in similar cases, e.g. in the tourist attraction section. The results are practical examples on how to create experiences using media technology within a tourist attraction. The studies resulted in applications with social media, user generated content, and Proxemic dimensions in focus. These practical examples might form a basis for influencing a future concept for tourist attractions to use.Finally a social media game concept is proposed, the concept is combining ubiquitous information, social media and a game application. This social media game concept shows how it would be possible to integrate the experience in both the digital and the physical world involving more than one person. The participants in the game are visitors both inside and outside the zoo. The media game concept creates a new enhancing experience by using media techniques such as a wireless sensor network, social media, and applications used both on smartphones and computers.The contribution of this work is the idea of using a game concept to create new experiences in a tourist attraction. This work shows how a game concept could combine the physical and digital worlds. The concept suggest that to create experiences for different visitors, the information should adapt to the visitors as well as letting visitors become part of the experience with, e.g., user generated content. This concept would make it possible for zoos and visitors to expand the user experience-timespan to include the time before, during, and after the visit.
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| 4. |
- Georgakis, Apostolos, 1975-, et al.
(författare)
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Spread spectrum wavelet watermarking system
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Lately attention has been focused on wavelet-based watermarking because of its compatibility with the newly developed JPEG 2000 image compression scheme. The major setback associated with wavelet-based watermarking is its vulnerability to geometric distortion caused by the lack of invariance property of wavelet transform. The domain of digital watermarking focused on spread spectrum based technique because of its excellent antijamming feature in wireless communication. However existing digital watermarking systems based on spread spectrum technique are yet to replay the anti-jamming feature in wireless communication, hence have not yielded the desired fully robust characteristics. Existing geometric invariant spread spectrum watermarking systems are complex, difficult to implement and unreliable. In our view this is due to inability of researchers to faithfully implement spread spectrum principle. Our investigation showed that most spread spectrum based watermarking faithfully implement the embedding process but fail to despread the signal before detection as required in a typical wireless spread spectrum communication. In this project we propose a simple spread spectrum wavelet watermarking system that is secure, tuneable and fully robust to all known forms and severities of attacks. The novel feature of our watermarking system design is its model as a communication system with the original (host) image representing the communication channel, the watermark represent the message (base band) signal and the legal and malicious attacks represent the noise, interference or jamming of the message signal. Experimental results from our system showed a replay of the excellent anti-jamming feature of spread spectrum communication technique and confirm the superior performance of our system over existing correlation-based spread spectrum wavelet watermarking system.
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| 5. |
- Karlsson, Johannes, 1977-
(författare)
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Wireless video sensor network and its applications in digital zoo
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Most computing and communicating devices have been personal computers that were connected to Internet through a fixed network connection. It is believed that future communication devices will not be of this type. Instead the intelligence and communication capability will move into various objects that surround us. This is often referred to as the "Internet of Things" or "Wireless Embedded Internet". This thesis deals with video processing and communication in these types of systems. One application scenario that is dealt with in this thesis is real-time video transmission over wireless ad-hoc networks. Here a set of devices automatically form a network and start to communicate without the need for any previous infrastructure. These devices act as both hosts and routers and can build up large networks where they forward information for each other. We have identified two major problems when sending real-time video over wireless ad-hoc networks. One is the reactive design used by most ad-hoc routing protocols. When nodes move some links that are used in the communication path between the sender and the receiver may disappear. The reactive routing protocols wait until some links on the path breaks and then start to search for a new path. This will lead to long interruptions in packet delivery and does not work well for real-time video transmission. Instead we propose an approach where we identify when a route is about to break and start to search for new routes before this happen. This is called a proactive approach. Another problem is that video codecs are very sensitive for packet losses and at the same time the wireless ad-hoc network is very error prone. The most common way to handle lost packets in video codecs is to periodically insert frames that are not predictively coded. This method periodically corrects errors regardless there has been an error or not. The method we propose is to insert frames that are not predictively coded directly after a packet has been lost, and only if a packet has been lost. Another area that is dealt with in this thesis is video sensor networks. These are small devices that have communication and computational capacity, they are equipped with an image sensor so that they can capture video. Since these devices in general have very limited resources in terms of energy, computation, communication and memory they demand a lot of the video compression algorithms used. In standard video compression algorithms the complexity is high for the encoder while the decoder has low complexity and is just passively controlled by the encoder. We propose video compression algorithms for wireless video sensor networks where complexity is reduced in the encoder by moving some of the image analysis to the decoder side. We have implemented our approach on actual low-power sensor nodes to test our developed algorithms. Finally we have built a "Digital Zoo" that is a complete system including a large scale outdoor video sensor network. The goal is to use the collected data from the video sensor network to create new experiences for physical visitors in the zoo, or "cyber" visitors from home. Here several topics that relate to practical deployments of sensor networks are addressed.
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| 6. |
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| 7. |
- Khan, Muhammad Sikandar Lal, 1988-
(författare)
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Presence through actions : theories, concepts, and implementations
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During face-to-face meetings, humans use multimodal information, including verbal information, visual information, body language, facial expressions, and other non-verbal gestures. In contrast, during computer-mediated-communication (CMC), humans rely either on mono-modal information such as text-only, voice-only, or video-only or on bi-modal information by using audiovisual modalities such as video teleconferencing. Psychologically, the difference between the two lies in the level of the subjective experience of presence, where people perceive a reduced feeling of presence in the case of CMC. Despite the current advancements in CMC, it is still far from face-to-face communication, especially in terms of the experience of presence.This thesis aims to introduce new concepts, theories, and technologies for presence design where the core is actions for creating presence. Thus, the contribution of the thesis can be divided into a technical contribution and a knowledge contribution. Technically, this thesis details novel technologies for improving presence experience during mediated communication (video teleconferencing). The proposed technologies include action robots (including a telepresence mechatronic robot (TEBoT) and a face robot), embodied control techniques (head orientation modeling and virtual reality headset based collaboration), and face reconstruction/retrieval algorithms. The introduced technologies enable action possibilities and embodied interactions that improve the presence experience between the distantly located participants. The novel setups were put into real experimental scenarios, and the well-known social, spatial, and gaze related problems were analyzed.The developed technologies and the results of the experiments led to the knowledge contribution of this thesis. In terms of knowledge contribution, this thesis presents a more general theoretical conceptual framework for mediated communication technologies. This conceptual framework can guide telepresence researchers toward the development of appropriate technologies for mediated communication applications. Furthermore, this thesis also presents a novel strong concept – presence through actions - that brings in philosophical understandings for developing presence- related technologies. The strong concept - presence through actions is an intermediate-level knowledge that proposes a new way of creating and developing future 'presence artifacts'. Presence- through actions is an action-oriented phenomenological approach to presence that differs from traditional immersive presence approaches that are based (implicitly) on rationalist, internalist views.
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| 8. |
- Le, Hung Son, 1973-
(författare)
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Face Recognition : A Single View Based HMM Approach
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation addresses the challenges of giving computers the ability of doing face recognition, i.e. discriminate between different faces. Face recognition systems are commonly trained with a database of face images, becoming “familiar” with the given faces. Many reported methods rely heavily on training database size and representativenes. But collecting training images covering, for instance, a wide range of viewpoints, different expressions and illumination conditions is difficult and costly. Moreover, there may be only one face image per person at low image resolution or quality. In these situations, face recognition techniques usually suffer serious performance drop. Here we present effective algorithms that deal with single image per person database, despite issues with illumination, face expression and pose variation.Illumination changes the appearance of a face in images. Thus, we use a new pyramid based fusion method for face recognition under arbitrary unknown lighting. This extended approach with logarithmic transform works efficiently with a single image. The produced image has better contrast at both low and high ranges, i.e. has more visible details than the original one. An improved method works with high dynamic range images, useful for outdoor face images.Face expressions also modify the images’ appearance. An extended Hidden Markov Models (HMM) with a flexible encoding scheme treats images as an ensemble of horizontal and vertical strips. Each person is modeled by Joint Multiple Hidden Markov Models (JM-HMMs). This approach offers computational advantages and the good learning ability from just a single sample per class. A fast method simulated JM-HMM functionality is then derived. The new method with abstract observations and a simplified similarity measurement does not require retraining HMMs for new images or subjects. Pose invariant recognition from a single sample image per person was overcome by using the wire frame Candide face model for the synthesis of virtual views. This is one of the support functions of our face recognition system, WAWO. The extensive experiments clearly show that WAWO outperforms the state-of-the-art systems in FERET tests.
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