• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 179
  • 61
  • 35
  • 25
  • 17
  • 12
  • 11
  • 7
  • 7
  • 7
  • 4
  • 4
  • 3
  • 2
  • 1
  • Tagged with
  • 393
  • 153
  • 115
  • 101
  • 83
  • 79
  • 74
  • 61
  • 57
  • 56
  • 41
  • 39
  • 38
  • 34
  • 33
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

The Design of a Video Acquisition System for JSF

Vu, Doug, Roach, John 10 1900 (has links)
ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, Nevada / The F-35 program, known as the Joint Strike Fighter (JSF), is the largest DOD program ever awarded. There are three F-35 variations, each intended to meet the specific needs of the Air Force, Navy, Marine Corps, and Allies. The F-35 Joint Strike Fighter represents the newest advanced military aircraft to make use of Fibre Channel as its primary avionics information transport network. In addition to its use for carrying tactical information systems data, the Fibre Channel network will also transport the real-time digital video used in the cockpit; primarily the pilot's helmet mounted display (HMD) and the high-resolution configurable panoramic cockpit display (PCD). In addition to the fighter's instrumentation configuration for orange wire and avionics data, the aircraft will carry a separate instrumentation package to allow for both the recording and telemetry of either high-resolution Fibre Channel digital video or standard resolution analog video inputs during flight tests. This multiplexer is designed to record cockpit video and audio data, while supporting an option for the test engineer to select up to three out of eight video and audio inputs for real-time telemetry to the ground. This paper describes the architecture of this system, along with the techniques used to reduce the 5 MBps Fibre Channel digital video to a bandwidth acceptable for telemetry.
22

A COMPARISON OF VIDEO COMPRESSION ALGORITHMS

Thom, Gary A., Deutermann, Alan R. 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Compressed video is necessary for a variety of telemetry requirements. A large number of competing video compression algorithms exist. This paper compares the ability of these algorithms to meet criteria which are of interest for telemetry applications. Included are: quality, compression, noise susceptibility, motion performance and latency. The algorithms are divided into those which employ inter-frame compression and those which employ intra-frame compression. A video tape presentation will also be presented to illustrate the performance of the video compression algorithms.
23

Indexation de vidéos et de maillages 3D dans le contexte MPEG-7

Zaharia, Titus 01 December 2001 (has links) (PDF)
Cette thèse relève de l'indexation et de la représentation par le contenu des données multimédias, dans le contexte spécifique de la normalisationinternationale de l'image et notamment dans le cadre du processus de standardisation MPEG-7.<br /><br />Nous proposons tout d'abord de nouvelles mesures de similarité pour les descriptions de mouvement par modèles paramétriques 2D, fondées sur une famille de fonctions distance entre les champs de vitesses. Les problèmes d'optimisation en temps de calcul, d'alignement spatio-temporel et de pondération des composantes translationnelle et homogène de mouvement sont analysés et une solution mathématique proposée, mise en oeuvre et évaluée objectivement sur les bases de test naturelle et synthétique avec vérité terrain, que nous avons constituées et qui ont été retenues pour l'évaluation des descripteurs de mouvement MPEG-7.<br /><br />Deux descripteurs de forme pour indexer des modèles 3D maillés sont ensuite proposés. Partant des propriétés d'invariance géométrique et topologique que doit satisfaire naturellement un descripteur de forme d'objet 3D maillé, nous avons tout d'abord défini le spectre de forme 3D, que nous avons proposé et promu dans le standard MPEG-7. Celui-ci exploite uniquement la structure géométrique locale d'une surface 3D, fournit une représentation très compacte, mais présente une grande sensibilité aux descriptions topologiques des maillages. En considérant la transformée de Hough 3D d'un maillage, nous avons ensuite construit le descripteur de Hough 3D optimisé, intrinsèquement invariant aux changements de connexité, rendu indépendant aux transformations géométriques et optimisé en terme de compacité de représentation, via une partition invariante aux changements de repère canonique de la sphère unité.<br /><br />Enfin, nous proposons une plate-forme d'indexation compatible MPEG-7, intégrant des outils d'annotation, de navigation, de visualisation et de requêtes par similarité, et supportant des applications comme l'archivage vidéo, la vidéo cliquable ou l'indexation MPEG-7 de la langue des signes française. L'ensemble logiciel ainsi réalisé démontre pour la première fois en grandeur réelle, pour les applications d'indexation multimédia considérées, le caractère effectivement opérationnel des schémas de description génériques, normalisés MPEG7.
24

Human visual system based object extraction for video coding

Fergusson, Robert Johnstone January 1999 (has links)
No description available.
25

Advanced error management in high-speed communication networks

Green, Robert James January 2000 (has links)
No description available.
26

Multiplexing video traffic using frame-skipping aggregation technique.

January 1998 (has links)
by Alan Yeung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 53-[56]). / Abstract also in Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- MPEG Overview --- p.5 / Chapter 3 --- Framework of Frame-Skipping Lossy Aggregation --- p.10 / Chapter 3.1 --- Video Frames Delivery using Round-Robin Scheduling --- p.10 / Chapter 3.2 --- Underflow Safety Margin on Receiver Buffers --- p.12 / Chapter 3.3 --- Algorithm in Frame-Skipping Aggregation Controller --- p.13 / Chapter 4 --- Replacement of Skipped Frames in MPEG Sequence --- p.17 / Chapter 5 --- Subjective Assessment Test on Frame-Skipped Video --- p.21 / Chapter 5.1 --- Test Settings and Material --- p.22 / Chapter 5.2 --- Choice of Test Methods --- p.23 / Chapter 5.3 --- Test Procedures --- p.25 / Chapter 5.4 --- Test Results --- p.26 / Chapter 6 --- Performance Study --- p.29 / Chapter 6.1 --- Experiment 1: Number of Supportable Streams --- p.31 / Chapter 6.2 --- Experiment 2: Frame-Skipping Rate When Multiplexing on a Leased T3 Link --- p.33 / Chapter 6.3 --- Experiment 3: Bandwidth Usage --- p.35 / Chapter 6.4 --- Experiment 4: Optimal USMT --- p.38 / Chapter 7 --- Implementation Considerations --- p.41 / Chapter 8 --- Conclusions --- p.45 / Chapter A --- The Construction of Stuffed Artificial B Frame --- p.48 / Bibliography --- p.53
27

Suporte de serviços MPEG-2 em redes de banda larga

Silva, Joaquim Fernando Fernandes da January 1997 (has links)
Dissertação apresentada para obtenção do grau de Mestre em Engenharia Electrotécnica e de Computadores, na Faculdade de Engenharia da Universidade do Porto, sob a orientação do Prof. Doutor José Ruela Fernandes
28

La plate-forme RAMSES pour un triple écran interactif : application à la génération automatique de télévision interactive / The RAMSES platform for triple display : application to automatic generation of interactive television

Royer, Julien 16 December 2009 (has links)
Avec la révolution du numérique, l’usage de la vidéo a fortement évolué durant les dernières décennies, passant du cinéma à la télévision, puis au web, du récit fictionnel au documentaire et de l’éditorialisation à la création par l’utilisateur. Les médias sont les vecteurs pour échanger des informations, des connaissances, des « reportages » personnels, des émotions... L’enrichissement automatique des documents multimédias est toujours un sujet de recherche depuis l’avènement des médias. Dans ce contexte, nous proposons dans un premier temps une modélisation des différents concepts et acteurs mis en œuvre pour analyser automatiquement des documents multimédias afin de déployer dynamiquement des services interactifs en relation avec le contenu des médias. Nous définissons ainsi les concepts d’analyseur, de service interactif, de description d’un document multimédia et enfin les fonctions nécessaires pour faire interagir ceux-ci. Le modèle d’analyse obtenu se démarque de la littérature en proposant une architecture modulaire, ouverte et évolutive. Nous présentons ensuite l’implantation de ces concepts dans le cadre d’un prototype de démonstration. Ce prototype permet ainsi de mettre en avant les contributions avancées dans la description des modèles. Une implantation ainsi que des recommandations sont détaillées pour chacun des modèles. Afin de montrer les résultats d’implantation des solutions proposées sur la plateforme telles que les standards MPEG-7 pour la description, MPEG-4 BIFS pour les scènes interactives ou encore OSGI pour l’architecture générale, nous présentons différents exemples de services interactifs intégrés dans la plateforme. Ceux-ci permettent de vérifier les capacités d’adaptation aux besoins d’un ou plusieurs services interactifs. / The concept developed in this thesis is to propose an architecture model allowing automatic multimedia analysis and inserting pertinent interactive contents accordingly to multimedia content. Until nowadays, studies are mainly trying to provide tools and frameworks to generate a full description of the multimedia. It can be compared as trying to describe the world since the system must have huge description capabilities. Actually, it is not possible to represent the world through a tree of concepts and relationships due to time and computer limitations. Therefore, according to the amount of multimedia analyzers developed all over the world, this thesis proposes a platform able to host, combine and share existing multimedia analyzers. Furthermore, we only consider user’s requirements to select only required elements from multimedia platform to analyze the multimedia. In order to easily adapt the platform to the service requirements, we propose a modular architecture based on plug-in multimedia analyzers to generate the contextual description of the media. Besides, we provide an interactive scene generator to dynamically create related interactive scenes. We choose the MPEG-7 standard to implement the multimedia’s description and MPEG-4 BIFS standard to implement interactive scenes into multimedia. We also present experimental results on different kind of interactive services using video real time information extraction. The main implemented example of interactive services concerns an interactive mobile TV application related to parliament session. This application aims to provide additional information to users by inserting automatically interactive contents (complementary information, subject of the current session…) into original TV program. In addition, we demonstrate the capacity of the platform to adapt to multiple domain applications through a set of simple interactive services (goodies, games...).
29

Implementation of MPEG-4 Video Encoder/Decoder on Microprocessors

Lee, Yu-jen 14 August 2004 (has links)
Digital image data requires large compression ratio in applications like internet, communication and audio-visual environment. In this thesis, we realize the MPEG-4 codec standard on the ARM9-based platform and improve the execution performance by efficient implementations of the core operations such as Motion Estimation and DCT. In the assembly codes obtained by directly compiling the C codes, there exists a lot of redundant checking which causes a large amount of execution time waste. We rewrite some of the compiled assembly codes to improve the execution efficiency using a variety of techniques such as loop-unrolling and data-type optimization. We also analyze the experimental results using several benchmark video sequences with different modes.
30

Mpeg Video Coding Improved by Mask Operation

Shieh, Jia-Horng 13 July 2000 (has links)
MPEG is a primary standards for dynamic image compression. The error can be introduced in the quantization process of the block DCT transformation . In this sense, the shape compensation by Boolean filter is proposed by us to adjust the intensity distribution of the motion compensated image. That is, our dynamic images are coded by the kinds of Boolean filter in addition to motion vectors after DCT coding. Boolean operation is usually applied to the binary images. The minterms of Boolean operations can be reprensented by masks. For the gray level images the mask operation is changed to be the more complex window operations. More clearly, there are two masks for a miniterm. One is a complement mask. The other is a maximum or minium window. For coding efficiency, in this paper a common complemented mask is used for two miniterms. In this sense, our Boolean filters are limited in a category of two miniterms with a same complemented structure. Experiment results have demonstrated that images going through the extra Boolean filtering have better visual quality than images processed by motion compensation only. The price is paid by the coding complexity and a relatively simple decoding structure. However, it is the decoding process which is more crucial in real time play. Therefore, we successfully integrated the Boolean filtering into MPEG-1 system in software implementation.

Page generated in 0.0467 seconds