http://www.visnet-noe.org/dokuwiki/ 2009-06-11T16:25:38+02:00 http://www.visnet-noe.org/dokuwiki/ http://www.visnet-noe.org/dokuwiki/lib/images/favicon.ico text/html 2008-06-27T14:41:24+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=access_control_architecture&rev=1214570484&do=diff An access control architecture has been designed to control access across a number of separate local networks, which may be owned by different organisations, and which may have different access policy and roles. The architecture consists of a number of web services that are deployed on each local network. The web services enable a requestor access to applications or encrypted data across these local networks. text/html 2008-06-06T14:07:42+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=access_security&rev=1212754062&do=diff One of the main security concerns for Collaborative Working Environment (CWE) and Collaborative Virtual Environments has to do with the management and distribution of data or resources amongst a group of users. For any proposed CWE scenario, it must be possible to control access to data and applications within the CWE. This must take into account the requirements of the group of users involved, as well as the requirements of the multiple domains across which the virtual CWE is physically located… text/html 2008-07-04T17:44:42+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=basic_architecture&rev=1215186282&do=diff The VISNET II Wyner-Ziv (WZ) video codec corresponds to an extension of the VISNET I WZ video codec. The VISNET I WZ codec adopted a Stanford based WZ video coding architecture whose modules have been improved and complemented in time to improve the performance and the functionalities. text/html 2008-07-04T16:02:47+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=beyond_coding_tools&rev=1215180167&do=diff It is presently more and more accepted that Distributed Source Coding (DSC) principles are leading to a variety of tools which may help to solve different problems, not only video coding but also, e.g., authentication, tampering detection, and secure biometrics. In this context, it was considered worthwhile to go beyond coding in VISNET II to understand better which are the other possibilities of DSC, eventually learning something that can be used to improved DVC: text/html 2009-05-12T11:48:20+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=computer_vision_and_image_processing&rev=1242121700&do=diff 2009 Conference Name DateConference VenueSubmission DeadlineVMV 2009 Vision, Modeling, and Visualization WorkshopNovember 16-18, 2009Braunschweig, GermanyJune 14, 2009CVMP 2009 6th European Conference on Visual Media ProductionNovember 12-13, 2009London, UKJune 19, 2009ICIP 2009 IEEE International Conference on Image ProcessingNovember 7-11, 2009Cairo, EgyptJanuary 30, 2009 ISMAR 2009 International Symposium on Mixed and Augmented RealityOctober 19-23, 2009Orlando FloridaMay 23, 2009 ICCV 2009 I… text/html 2009-04-03T19:51:53+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=context-based_adaptation&rev=1238781113&do=diff Future media Internet will allow new applications to be realised with support for ubiquitous media-rich content service technologies. Virtual collaboration [1] is one of them, which allows remotely located partners to meet in a virtual environment using state-of-the-art communication and audiovisual technologies. However, given the diversity of scenarios and usage environments in these types of applications, access to content is likely to pose significant challenges, which need to be addressed t… text/html 2008-07-03T15:05:33+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=digital_rights_management&rev=1215090333&do=diff Digital Rights Management (DRM) systems provide a means for content creators and distributors to address the unauthorised copying issue. These systems enable the creation, distribution and consumption of digital content according to the permissions and constraints stated by the content creator. A DRM system provides intellectual property protection by encrypting, or protecting in other way the digital content so that it can only be accessed and used by authorized users according to the digital r… text/html 2008-07-04T15:54:01+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=distributed_video_coding&rev=1215179641&do=diff With the wide deployment of mobile and wireless networks, there are a growing number of applications which do not fit the typical down-link model but rather an up-link model where many senders deliver data to a central receiver. Examples of these applications are wireless digital video cameras, low-power video sensor networks, surveillance cameras, and wireless video teleconferencing systems. Typically, these emerging applications require light encoding or a flexible distribution of the codec co… text/html 2008-07-03T10:37:01+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=editing&rev=1215074221&do=diff Syntax instructions for a dokuwiki can be found here. Equations have to be instered as images at the moment. Images can be inserted using the Media Manager in the toolbar on the editing page. Once you have uploaded your image you can include it by double clicking on its icon in the Media Manager or include it in the text with double curly brackets. More syntax on images can be found here. text/html 2008-11-04T09:46:18+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=external_links&rev=1225788378&do=diff Audiovisual Media Projects Industry Sites Other Related Sites * Face Recognition Website text/html 2008-10-30T11:49:53+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=human_analysis&rev=1225363793&do=diff Human motion analysis or more generally looking at people is one of the most active research areas in computer vision. The general goals are to detect and track persons, recognize them and interpret their behaviour based on the visual analysis of images or videos. This topic has attracted great interest due to its promising applications in diverse areas such as access control, human computer interaction, smart rooms, visual surveillance, virtual reality, video conferencing and content based mult… text/html 2008-05-28T11:45:03+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=media_quality_optimisation_over_networks&rev=1211967903&do=diff “Media quality optimisation over networks” addresses a number of issues related with the transfer of multimedia content across networks (and especially those arising from the use of wireless access links). On one hand, it is necessary to set-up the required resources so that the expected end-to-end Quality of Service (QoS) may be achieved; negotiation of suitable traffic and QoS parameters and optimization of network resources should take into account the available information (descriptors) conc… text/html 2008-05-27T11:42:05+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=mpeg-4_avc_part_10_also_h.264&rev=1211881325&do=diff In 2001, ISO/IEC MPEG and ITU-T VCEG decided again to join efforts to develop another video coding standard which had the target to provide about 50% more compression efficiency compared to all previous video coding standards. The Advanced Video Coding (AVC) standard, also MPEG-4 Part 10, and ITU-T H.264, developed by the so-called Joint Video Team (JVT), is the first of the XVC era and became available in 2003 . While the basic coding architecture relies on the well known transform-based, motio… text/html 2008-05-27T11:41:09+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=mpeg-4_visual_part_2&rev=1211881269&do=diff While most video coding standards specify hybrid video coding solutions for frame based content, the MPEG-4 Visual or MPEG-4 Part 2 standard also specifies hybrid video coding solutions for object-based content, notably arbitrarily shaped video objects. Since human beings do not want to interact with abstract entities, such as pixels, but rather with meaningful entities that are part of the scene, the concept of object is central to MPEG-4. MPEG-4 models an audiovisual scene as a composition of … text/html 2008-06-06T11:49:59+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=multi-domain_authentication_and_authorisation&rev=1212745799&do=diff Authentication Authentication is the process of checking that a requestor or other local network is who (or what) they claim to be. Authentication requirements include: * The ability to register, recognise and uniquely identify each user. * That the local network can identify the requestor responsible for application requests. * That users should not be able to be impersonated. * The ability of the user to use other local networks pseudonymously (anonymously to the other local network… text/html 2008-05-27T11:42:53+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=multiview_video_coding&rev=1211881373&do=diff Since our world is not a 2D world, 3D has always been an exciting target in visual representation. 3D experiences may be provided through multiview video (MVV), notably: i) 3D video (also called stereo) which brings a depth impression of a scene, and ii) free viewpoint video (FVV) which allows an interactive selection of the viewpoint and direction within certain ranges. Of course, 3D experiences may require special 3D display technology but many new products have been announced and exhibited re… text/html 2008-05-23T12:51:08+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=non-normative_video_coding&rev=1211539868&do=diff In order to provide interoperability between different compliant codecs, it is essential for a coding standard to fix the decoding procedure and the bitstream syntax and semantics. However, the encoding procedure and encoding tools do not have to be defined for video codec’s, which is a very useful feature. Since standards are always a constraint on codec design freedom, it is important to make them as minimally constraining as possible in order that the standard may evolve as much as possible t… text/html 2008-05-28T09:39:36+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=non-normative_video_coding_tools&rev=1211960376&do=diff In order to provide interoperability between different compliant codecs, it is essential for a coding standard to fix the decoding procedure and the bitstream syntax and semantics. However, the encoding procedure and encoding tools do not have to be defined for video codec’s, which is a very useful feature. Since standards are always a constraint on codec design freedom, it is important to make them as minimally constraining as possible in order that the standard may evolve as much as possible t… text/html 2008-07-04T17:26:57+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=performance&rev=1215185217&do=diff Present VISNET II video coding performance for several GOP sizes. GOP=2 Foreman Soccer [ Foreman, GOP=2] [ Soccer, GOP=2] Hall Monitor Coastguard [ Hall Monitor, GOP=2] [ Coastguard, GOP=2] GOP=4 GOP=8 text/html 2008-05-27T11:43:22+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=reconfigurable_video_coding&rev=1211881402&do=diff Looking to the past, it seems the MPEG strategy has been to develop a new video coding standard (with many profiles) more or less every 5 years, each one bringing more or less a 50% compression efficiency gain. Of course, these coding standards have a significant overlap in terms of coding tools, e.g. DCT transform, and motion compensation, which are combined with new tools in a rather rigid coding architecture. With time, it became increasingly clear that the video coding market was very dynami… text/html 2008-12-12T18:27:29+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=scalable_video_coding&rev=1229102849&do=diff Scalable video coding has been for many years a target in the video coding community and also in standardization bodies … scalability is after all an ‘elegant’ concept … Scalability can be seen as the functionality which allows the creation of useful bitstreams after discarding some of parts of the initial bitstream, while ideally it is possible to achieve (with the remaining bitstream) a RD performance, at any supported spatial, temporal, or SNR resolution, that is comparable to single-layer co… text/html 2008-05-26T16:58:55+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=search_and_retrieval&rev=1211813935&do=diff This activity is related to a reference end-to-end multimedia search and retrieval architecture which will allow efficient implementation in different environments. The goal of this exploration activity is twofold, addressing both image and video multimedia search engines. For this reason, the exploration activity is subdivided in two different tasks: text/html 2008-07-04T12:45:18+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=side_information_creation_process&rev=1215168318&do=diff Several frame interpolation techniques can be employed at the Wyner-Ziv decoder to generate the side information (YWZ). The choice of the techniques used can significantly influence the codec rate-distortion (RD) performance. More accurate side information through frame interpolation means less errors (YWZ is more similar to XWZ); therefore the decoder needs to request less parity bits from the encoder and the bitrate is reduced for the same quality. The VISNET II WZ video decoder uses the block… text/html 2008-07-04T18:12:39+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=slepian-wolf_codec&rev=1215187959&do=diff The Slepian-Wolf codec is a key module in WZ coding architectures since it is responsible for correcting the errors in the side information, YWZ (the WZ frame estimation), generated at the decoder. Due to the relationship between Slepian-Wolf coding and channel coding, the Slepian-Wolf codec usually consists of an efficient channel codec. While the first WZ coding solutions using the architecture adopted in this deliverable have made use of turbo codes [1, 2], it is also possible to use other ch… text/html 2009-06-09T11:55:49+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=start&rev=1244541349&do=diff Array The research activities within VISNET II cover 3 thematic areas related to networked 2D/3D audiovisual systems and home platforms. This Wiki covers the 3 VISNET II related topics: Video Coding * Video Coding Standards * Non-Normative Video Coding * Distributed Video Coding text/html 2008-05-26T17:07:11+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=techniques_for_linking_content_to_corresponding_information_provided&rev=1211814431&do=diff Trying to address the problem of providing effective video search and retrieval algorithms, we have to face the problem of getting over the semantic gap, the gap between low level features (LLF) that can automatically extracted from a digital content and the “objects” which they represent. The algorithms currently available in literature are not yet sufficient to assure good results, exploitable in commercial solutions. Of course the problem arisen by the semantic gap is really difficult to solv… text/html 2008-07-04T15:45:47+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=test_conditions_and_benchmarks&rev=1215179147&do=diff It is important to compare the performances of the VISNET II Wyner-Ziv video codec with the new proposed tools regarding the most relevant WZ and conventional alternative video codecs. To allow fair comparisons it is essential to describe how the performances presented were obtained. The following sections describe the usual test conditions and benchmarks used. text/html 2008-07-04T17:22:59+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=the_berkeley_wz_video_coding_architecture&rev=1215184979&do=diff Almost at the same time of the Stanford Wyner-Ziv (WZ) coding solution, another WZ video coding approach has been proposed at UC Berkeley, known in the literature as PRISM. In summary, the PRISM codec works as follows: Encoder [PRISM Encoder] * Transform - Each video frame is divided into 8×8 samples blocks and a DCT is applied over each block. * Quantisation - A scalar quantiser is applied to the DCT coefficients corresponding to a certain target quality. * Classification - Before fur… text/html 2008-07-04T13:12:26+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=the_stanford_wz_video_coding_architecture&rev=1215169946&do=diff The Stanford Wyner-Ziv (WZ) video coding architecture was first proposed in 2002 for the pixel domain and later extended to the transform domain where DCT coefficients are WZ coded. In summary, the (more efficient) transform domain WZ video codec works as follows: text/html 2008-05-27T11:39:08+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=video_coding_standards&rev=1211881148&do=diff The main purpose of digital audiovisual coding technologies is to compress the original digital information into a much smaller number of bits, without an unacceptable degradation of the signal quality. Regarding video, the current coding paradigm is mostly based on temporal prediction between video frames to exploit the temporal redundancy, transform coding (e.g. using DCT, Discrete Cosine Transform) to exploit the spatial redundancy, quantisation of the transform coefficients to exploit irrele… text/html 2008-07-04T16:03:39+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=video_decoder_tools&rev=1215180219&do=diff Includes developed DVC tools which act at the video decoder side: * Advanced Motion Compensation Frame Interpolation for Side Information Creation * Improved Side Information Generation with Iterative Decoding * Improved Decoding Algorithm for DVC over Multipath Error Prone Wireless Channels * Hybrid Error Concealment for Distributed Video Coding text/html 2008-07-04T16:03:18+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=video_encoder_and_decoder_tools&rev=1215180198&do=diff Includes developed DVC tools which act both at the video encoder and decoder sides: * Design of an Efficient Low-Density Parity-Check Code for Distributed Video Coding * Scalable Distributed Video Coding as a New Scheme for Advanced Image Coding text/html 2008-07-04T16:04:03+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=video_encoder_tools&rev=1215180243&do=diff Includes developed DVC tools which act at the video encoder side: * Non-Linear Quantisation Technique for Distributed Video Coding * Low Complexity Hybrid Rate Control for Lower Complexity Distributed Video Decoding * Encoder Rate Control in a Distributed Video Coding System * Rate Allocation for Robust Video Streaming Based on Distributed Video Codin text/html 2008-05-28T11:11:28+02:00 http://www.visnet-noe.org/dokuwiki/doku.php?id=video_quality_optimisation_over_networks&rev=1211965888&do=diff Related Topics References Links