1000 resultados para video indexing


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A new generation of advanced surveillance systems is being conceived as a collection of multi-sensor components such as video, audio and mobile robots interacting in a cooperating manner to enhance situation awareness capabilities to assist surveillance personnel. The prominent issues that these systems face are: the improvement of existing intelligent video surveillance systems, the inclusion of wireless networks, the use of low power sensors, the design architecture, the communication between different components, the fusion of data emerging from different type of sensors, the location of personnel (providers and consumers) and the scalability of the system. This paper focuses on the aspects pertaining to real-time distributed architecture and scalability. For example, to meet real-time requirements, these systems need to process data streams in concurrent environments, designed by taking into account scheduling and synchronisation. The paper proposes a framework for the design of visual surveillance systems based on components derived from the principles of Real Time Networks/Data Oriented Requirements Implementation Scheme (RTN/DORIS). It also proposes the implementation of these components using the well-known middleware technology Common Object Request Broker Architecture (CORBA). Results using this architecture for video surveillance are presented through an implemented prototype.

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Automatically extracting interesting objects from videos is a very challenging task and is applicable to many research areas such robotics, medical imaging, content based indexing and visual surveillance. Automated visual surveillance is a major research area in computational vision and a commonly applied technique in an attempt to extract objects of interest is that of motion segmentation. Motion segmentation relies on the temporal changes that occur in video sequences to detect objects, but as a technique it presents many challenges that researchers have yet to surmount. Changes in real-time video sequences not only include interesting objects, environmental conditions such as wind, cloud cover, rain and snow may be present, in addition to rapid lighting changes, poor footage quality, moving shadows and reflections. The list provides only a sample of the challenges present. This thesis explores the use of motion segmentation as part of a computational vision system and provides solutions for a practical, generic approach with robust performance, using current neuro-biological, physiological and psychological research in primate vision as inspiration.

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This research establishes the feasibility of using a network centric technology, Jini, to provide a grid framework on which to perform parallel video encoding. A solution was implemented using Jini and obtained real-time on demand encoding of a 480 HD video stream. Further, a projection is made concerning the encoding of 1080 HD video in real-time, as the current grid was not powerful enough to achieve this above 15fps. The research found that Jini is able to provide a number of tools and services highly applicable in a grid environment. It is also suitable in terms of performance and responds well to a varying number of grid nodes. The main performance limiter was found to be the network bandwidth allocation, which when loaded with a large number of grid nodes was unable to handle the traffic.

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Our research investigates the impact that hearing has on the perception of digital video clips, with and without captions, by discussing how hearing loss, captions and deafness type affects user QoP (Quality of Perception). QoP encompasses not only a user's satisfaction with the quality of a multimedia presentation, but also their ability to analyse, synthesise and assimilate informational content of multimedia . Results show that hearing has a significant effect on participants’ ability to assimilate information, independent of video type and use of captions. It is shown that captions do not necessarily provide deaf users with a ‘greater level of information’ from video, but cause a change in user QoP, depending on deafness type, which provides a ‘greater level of context of the video’. It is also shown that post-lingual mild and moderately deaf participants predict less accurately their level of information assimilation than post-lingual profoundly deaf participants, despite residual hearing. A positive correlation was identified between level of enjoyment (LOE) and self-predicted level of information assimilation (PIA), independent of hearing level or hearing type. When this is considered in a QoP quality framework, it puts into question how the user perceives certain factors, such as ‘informative’ and ‘quality’.

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The literature has identified issues around transitions among phases for all pupils (Cocklin, 1999) including pupils with special educational needs (SEN) (Morgan 1999, Maras and Aveling 2006). These issues include pupils’ uncertainties and worries about building size and spatial orientation, exposure to a range of teaching styles, relationships with peers and older pupils as well as parents’ difficulties in establishing effective communications with prospective secondary schools. Research has also identified that interventions to facilitate these educational transitions should consider managerial support, social and personal familiarisation with the new setting as well as personalised learning strategies (BECTA 2004). However, the role that digital technologies can play in supporting these strategies or facilitating the role of the professionals such as SENCos and heads of departments involved in supporting effective transitions for pupils with SEN has not been widely discussed. Uses of ICT include passing references of student-produced media presentations (Higgins 1993) and use of photographs of activities attached to a timetable to support familiarisation with the secondary curriculum for pupils with autism (Cumine et al. 1998).

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The Escherichia coli O26 serogroup includes important food-borne pathogens associated with human and animal diarrheal disease. Current typing methods have revealed great genetic heterogeneity within the O26 group; the data are often inconsistent and focus only on verotoxin (VT)-positive O26 isolates. To improve current understanding of diversity within this serogroup, the genomic relatedness of VT-positive and -negative O26 strains was assessed by comparative genomic indexing. Our results clearly demonstrate that irrespective of virulence characteristics and pathotype designation, the O26 strains show greater genomic similarity to each other than to any other strain included in this study. Our data suggest that enteropathogenic and VT-expressing E. coli O26 strains represent the same clonal lineage and that W-expressing E. coli O26 strains have gained additional virulence characteristics. Using this approach, we established the core genes which are central to the E. coli species and identified regions of variation from the E. coli K-12 chromosomal backbone.

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We investigate the impact of captions on deaf and hearing perception of multimedia video clips. We measure perception using a parameter called Quality of Perception (QoP), which encompasses not only a user's satisfaction with multimedia clips, but also his/her ability to perceive, synthesise and analyse the informational content of such presentations. By studying perceptual diversity, it is our aim to identify trends that will help future implementation of adaptive multimedia technologies. Results show that although hearing level has a significant affect on information assimilation, the effect of captions is not significant on the objective level of information assimilated. Deaf participants predict that captions significantly improve their level of information assimilation, although no significant objective improvement was measured. The level of enjoyment is unaffected by a participant’s level of hearing or use of captions.

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The current state of the art and direction of research in computer vision aimed at automating the analysis of CCTV images is presented. This includes low level identification of objects within the field of view of cameras, following those objects over time and between cameras, and the interpretation of those objects’ appearance and movements with respect to models of behaviour (and therefore intentions inferred). The potential ethical problems (and some potential opportunities) such developments may pose if and when deployed in the real world are presented, and suggestions made as to the necessary new regulations which will be needed if such systems are not to further enhance the power of the surveillers against the surveilled.

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