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Document Server@UHasselt (59.068 recursos)

Repository of the University of Hasselt containing publications in the fields of statistics, computer science, information strategies and material from the Institute for behavioural sciences.

Dept. Mathematics-Physics-Informatics (WNI) - Expertise Centre for Digital Media (EDM)

Mostrando recursos 1 - 20 de 672

  1. Performance Evaluation of Scalable Distribution of Omni-Directional Video Sequences using H.264

    Quax, Peter; Issaris, Panagiotis; Liesenborgs, Jori; Lamotte, Wim
    In this paper, we present a scalable solution for distributing omni-directional video sequences to multiple viewers using advanced facilities provided by the H.264 codec. In contrast to traditional broadcast scenarios, in the context of omni- directional video, it is the consumer who de nes the camera view direction and viewport size. This hints to the fact that a single generic stream will generally not su ce as input for the client viewer application or device, but that a customized stream is required for each user. Transcoding such content on the y is widely regarded as a non-scalable solution, as will also be demonstrated in this paper. The proposed solu- tion to...

  2. Touch-based Interaction and Collaboration in Walk-up-and-use and Multi-user Environments

    Vanacken, Davy
    Touch-based interfaces are becoming increasingly ubiquitous: they can be found on a variety of hardware platforms, ranging from mobile phones to large public displays, and they allow a wide variety of applications, from singleuser casual games to multi-user tools that facilitate brainstorming. Although touch-based interaction is supposed to be intuitive and \natural", it nonetheless imposes speci c requirements on the accessibility of a user interface. Due to a lack of common conventions and consistency across applications, gestures are often di cult to discover and learn. Furthermore, since most touchsensitive hardware supports multi-touch input nowadays, it allows multiple people to interact simultaneously on a shared surface. This not only brings about...

  3. Ambient Intelligence: Third International Joint Conference, AmI 2012, Pisa, Italy, November 13-15, 2012, Proceedings

    This book constitutes the refereed proceedings of the third international Joint Conference on Ambient Intelligence, AmI held in Pisa, Italy, in November 2012. The 18 revised full papers and 5 short papers presented were carefully reviewed and selected from 47 (full papers) respectively 14 (short papers) submissions. From a scientific point of view, the papers make a multidisciplinary approach covering fields like computer science, human computer interaction, electrical engineering, industrial design, behavioral sciences, aimed at enriching physical environments with a network of distributed devices, such as sensors, actuators, and computational resources, in order to support users in their everyday activities....

  4. Understanding Complex Environments with the Feedforward Torch

    Vermeulen, Jo; Luyten, Kris; Coninx, Karin
    In contrast with design flaws that occur in user interfaces, design flaws in physical spaces have a much higher cost and impact. Software is in fact fairly easy to change and update in contrast with legacy physical constructions where updating their physical appearance is often not an option. We present the Feedforward Torch, a mobile projection system that targets the augmentation of legacy hardware with feedforward information. Feedforward explains users what the results of their action will be, and can thus be seen as the opposite of feedback. A first user study suggests that providing feedforward in these environments could...

  5. Raw Camera Image Demosaicing using Finite Impulse Response Filtering on Commodity GPU Hardware using CUDA

    Goorts, Patrik; Rogmans, Sammy; Bekaert, Philippe
    In this paper, we investigate demosaicing of raw camera images on parallel architectures using CUDA. To generate high-quality results, we use the method of Malvar et al., which incorporates the gradient for edgesensing demosaicing. The method can be implemented as a collection of finite impulse response filters, which can easily eb mapped to a parallel architecture. We investigated different trade-offs between memory operations and processor occupation to acquire maximum performance, and found a clear difference in optimization principles between different GPU architecture designs. We show that trade-offs are still important and not straightforward when using systems with massive fast processors...

  6. An Experimental Perspective on Factors Influencing Collaborative User Experience in Virtual Environments and Games

    Beznosyk, Anastasiia
    Collaboration between people is an essential component of daily life. With the growing use of computer technology in the last decades, it has become possible to interact with other people not only in real life but also virtually through collaborative virtual environments. Collaborative virtual environments are computer-based virtual spaces that enable users, although geographically dispersed, to be present in the same environment and to collaborate with each other. When creating a collaborative virtual environment one of the main challenges is to provide users with the ability to interact with each other in a natural and realistic manner. A lot of research has been done in this area; however,...

  7. System-on-Chip Architecture for Real-Time License Plate Segmentation

    Farinelli, Fabrizio; Motten, Andy; Claesen, Luc
    license plate recognition; segmentation; image processing; soc; fpga; computational video

  8. Analysis of an optical biosensor based on elastic light scattering from diamond-, glass-, and sapphire microspheres

    MURIB, Mohammed Sharif; Tran, Anh Quang; DE CEUNINCK, Ward; Sch??ning, J.M.; NESLADEK, Milos; Serpeng??zel, Ali; WAGNER, Patrick
    Deoxyribonucleic acid (DNA) and protein recognition are now standard tools in biology. In addition, the special optical properties of microsphere resonators expressed by the high quality factor (Q-factor) of whispering gallery modes (WGMs) or morphology dependent resonances (MDRs) have attracted the attention of the biophotonic community. Microsphere-based biosensors are considered as powerful candidates to achieve label-free recognition of single molecules due to the high sensitivity of their WGMs. When the microsphere surface is modified with biomolecules, the effective refractive index and the effective size of the microsphere change resulting in a resonant wavelength shift. The transverse electric (TE) and the...

  9. Intel Collaborative Research Institute - Sustainable Connected Cities

    Sch??ning, Johannes; Rogers, Yvonne; Bird, Jon; Capra, Lucia; McCann, Julie A.; Prendergast, David; Sheridan, Charles
    Cities are places where people, meet, exchange, work, live and interact. They bring people with di erent interests, experiences and knowledge close together. They are the centres of culture, economic development and social change. They o er many opportunities to innovate with technologies, from the infrastructures that underlie the sewers to computing in the cloud. One of the overarching goals of Intel's Collaborative Research Institute on Sustainable Connected Cities is to integrate the technological, economic and social needs of cities in ways that are sustainable and human-centred. Our objective is to inform, develop and evaluate services that enhance the quality of living in the city.

  10. Putting Dementia into Context : a Selective Literature Review of Assistive Applications for Users with Dementia and their Caregivers

    VOGT, Jo??l; Luyten, Kris; Van den Bergh, Jan; Coninx, Karin; Meier, Andreas
    People with dementia face a decline of their cognitive functions, including memory impairment and difficulty to orient in time and space. Assistive applications can ease the effects of dementia by assuming and supporting impaired functions. Context-awareness is an accepted paradigm for assistive applications. It enables interactive systems to react appropriately to situations that occur during daily routines of people with dementia. However, there currently is no recommended framework to view symptoms of dementia in terms of context and context-awareness. The aim of this paper is to inform designers in the early design stages of assistive applications how requirements and needs...

  11. Adaptive Memory Architecture for Real-Time Image Warping

    Motten, Andy; Claesen, Luc; Pan, Yun
    This paper presents a real time image warping module implemented in hardware. A look-up table (LUT) based reverse mapping is used to relate the source image to the warped image. Frame buffers or line buffers are often used to temporally store the source image. However these methods do not take the underlying pattern of the reverse mapping coordinates into account. The presented architecture uses an adaptable memory allocation which can change the depth and the position of the line buffer between lines. A real-time stereo rectification use case has been implemented to validate the operation of this module. Depending on...

  12. Trinocular Disparity Processor using a Hierarchic Classification Structure

    Motten, Andy; Claesen, Luc; Pan, Yun
    This paper presents a real-time trinocular disparity processor. The core module performs a pairwise segmented window matching for both the center-right and center-left image pair as their scaled down image pairs. The resulting cost functions are combined which results into nine different curves. A hierarchical classifier is presented which selects the most promising disparity value using information provided by the calculated cost curves and the pixels spatial neighborhood using a two level classification architecture. The disparity processor has been evaluated with an indoor dataset and with a real-time implementation using an FPGA and three cameras. Special care has been taken to reduce the memory

  13. Hardware/Software CoDesign of an Acceleration SoC for Interactive Digital Painting

    Claesen, Luc; Motten, Andy; Vandoren, Peter; Van Laerhoven, Tom; Van Reeth, Frank; Pan, Yun; Zheng, Ning; Yan, Xiaolang
    Novel digital paint systems use brush-like or real brush input for computer assisted graphics- and art-creation. This paper presents the hardware-software implementation of the real-time video processing algorithms for brush position, shape and bristle texture detection. The system has been implemented using a 5 megapixel camera and an FPGA system. The system consists of a dynamically reconfigurable image processing streaming architecture. It is heavily pipelined to keep the propagation delays within the strict timing requirements in order to enable the processing at camera video rate. Video processing blocks are realized in a modular way and interconnected by a dedicated programmable...

  14. Automated tracking of the mandibular canal in CBCT images using matching and multiple hypotheses methods

    Moris, Brecht; Claesen, Luc; Sun, Yi; Politis, Constantinus
    A method for the automated tracking of the mandibular canal in Cone Beam Computed Tomography images is presented. In contrast to most proposed methods a fully automated method is presented including the detection of the mental and mandibular foramen. Extraction of these points is done by searching for high-contrast gaps in the mandible. The path of the mandibular canal can then be tracked in between these two points using a matching technique consisting of a template function which maps spatial coordinates to a cost. The robustness of the tracking is increased by recursively tracking multiple hypotheses.

  15. Reflectance Model for Diffraction

    Cuypers, Tom; Haber, Tom; Bekaert, Philippe; Oh, Se Baek; Raskar, Ramesh
    We present a novel method of simulating wave effects in graphics using ray-based renderers with a new function: the Wave BSDF (Bidirectional Scattering Distribution Function). Reflections from neighboring surface patches represented by local BSDFs are mutually independent. However, in many surfaces with wavelength-scale microstructures, interference and diffraction requires a joint analysis of reflected wavefronts from neighboring patches. We demonstrate a simple method to compute the BSDF for the entire microstructure, which can be used independently for each patch. This allows us to use traditional ray-based rendering pipelines to synthesize wave effects. We exploit the Wigner Distribution Function (WDF) to create...

  16. Evaluation of Distribution of Panoramic Video Sequences in the eXplorative Television Project

    Quax, Peter; Issaris, Takis; Vanmontfort, Wouter; Lamotte, Wim
    In this paper, a scalable solution is presented for distributing panoramic video sequences to multiple viewers at high resolution and quality levels. In contrast to traditional broadcast scenarios, panoramic video enables the content consumer to manipulate the camera view direction and viewport size. By segmenting the panoramic input video into a set of separate sequences, transporting them over standard delivery channels and recombining them at end user side, bandwidth utilization is optimized and the quality of the video that is visualized is increased. The proposed solution, called the segmentation approach, is thoroughly explained and evaluated versus a single-stream solution with...

  17. As I am not you: accommodating user diversity through edaptive rehabilitation training for multiple sclerosis patients

    Octavia, Johanna; Coninx, Karin; Feys, Peter
    People who suffer from Multiple Sclerosis (MS) are unique individuals with their own characteristics and rehabilitation training needs. The great variation of MS symptoms and severity of the disease elevates a need to accomodate the diversity among its patients and support adaptive personalized training to meet every patients rehabilitation needs. Our research has focused on integrating adaptivity in rehabilitation training for MS patients. We introduced the automatic adjustment of difficulty levels as a type of adaptation that can be provided in MS rehabilitation training exercises. A user study has been carried out to investigate the outcome of this adaptation. An...

  18. Overlay Network Based Optimization of Data Flows in Large Scale Client-Server-based Game Architectures for Deployment on Cloud Platforms

    Quax, Peter; Vanmontfort, Wouter; Marx, Robin; Wijnants, Maarten; Lamotte, Wim
    In this overview paper, we present results that were obtained by combining a specific architectural design for Networked Virtual Environments (NVEs) with a generic optimization infrastructure for content streaming. Although the two are ???at first sight ??? targeting unrelated application areas, it turns out that the application knowledge available in the NVE architecture can effectively be used to instruct the adaptation infrastructure to change the way in which data is delivered to the end-user. The endeffect of these optimizations is a fine-grained ability for the combined architecture to deliver the required NVE content to the end-user while optimizing bandwidth usage. Such optimizations are very useful in mobile...

  19. Informing the Design of Situated Glyphs for a Care Facility

    Vermeulen, Jo; Kawsar, Fahim; Simeone, Adalberto L.; Kortuem, Gerd; Luyten, Kris; Coninx, Karin
    Informing caregivers by providing them with contextual medical information can significantly improve the quality of patient care activities. However, information flow in hospitals is still tied to traditional manual or digitised lengthy patient record files that are often not accessible while caregivers are attending to patients. Leveraging the proliferation of pervasive awareness technologies (sensors, actuators and mobile displays), recent studies have explored this information presentation aspect borrowing theories from context-aware computing, i.e., presenting subtle information contextually to support the activity at hand. However, the understanding of the information space (i.e., what information should be presented) is still fairly abstruse, which inhibits the deployment of such real-time activity support systems. To this end, this...

  20. Carpus: A Non-Intrusive User Identification Technique for Interactive Surfaces

    Ramakers, Raf; Vanacken, Davy; Luyten, Kris; Sch??ning, Johannes; Coninx, Karin
    Interactive surfaces have great potential for co-located collaboration because of their ability to track multiple inputs simultaneously. However, the multi-user experience on these devices could be enriched significantly if touch points could be associated with a particular user. Existing approaches to user identification are intrusive, require users to stay in a fixed position, or suffer from poor accuracy. We present a non-intrusive, high-accuracy technique for mapping touches to their corresponding user in a collaborative environment. By mounting a high-resolution camera above the interactive surface, we are able to identify touches reliably without any extra instrumentation, and users are able to move around the surface at will. Our technique, which leverages the back...

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