Dépouillements

Designing autonomous layered video coders / Nicholas Mastronarde in Signal processing. Image communication, Vol. 24 N° 6 (Juillet 2009) 

Public ISBD [article]  in Signal processing. Image communication > Vol. 24 N° 6 (Juillet 2009) . - pp. 417-436 Titre : Designing autonomous layered video coders Type de document : texte imprimé Auteurs : Nicholas Mastronarde, Auteur ; Mihaela van der Schaar, Auteur Article en page(s) : pp. 417-436 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Foresighted  rate-control  Layered  Markov  decision  process  Autonomous  layered  video  coding Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : Layered compression paradigms such as scalable, multiple description, and multi-view video coding, require coupled encoding decisions among layers to achieve optimal distortion performance under buffer constraints. Moreover, due to the dynamic and time-varying source characteristics, and temporal coupling of encoding decisions through the buffer constraints, it is not only necessary to consider the immediate rate–distortion impact of encoding decisions, but also their long-term rate–distortion impact. In other words, optimal encoding decisions must consider the coupling between layers and the coupling across time. In many scenarios, however, it may be impractical to make joint coding decisions for all of the layers. For instance, a two layer bitstream may be coded using different encoders for the base layer and enhancement layer, each with its own autonomous control plane; or, if the same encoder is used for multiple layers, then a joint decision process, which considers the aforementioned dependencies, may be too complex. In this paper, we propose a framework for autonomous decision making in layered video coders, which decouples the decision making processes at the various layers using a novel layered Markov decision process. We illustrate how this framework can be applied to decompose the decision processes for several typical layered video coders with different dependency structures and we observe that the performance of the proposed decomposition highly depends on the ability of the layers to model each other. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...] [article] Designing autonomous layered video coders [texte imprimé] / Nicholas Mastronarde, Auteur ; Mihaela van der Schaar, Auteur . - pp. 417-436. Electronique Langues : Anglais (eng) in Signal processing. Image communication > Vol. 24 N° 6 (Juillet 2009) . - pp. 417-436 Mots-clés : Foresighted  rate-control  Layered  Markov  decision  process  Autonomous  layered  video  coding Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : Layered compression paradigms such as scalable, multiple description, and multi-view video coding, require coupled encoding decisions among layers to achieve optimal distortion performance under buffer constraints. Moreover, due to the dynamic and time-varying source characteristics, and temporal coupling of encoding decisions through the buffer constraints, it is not only necessary to consider the immediate rate–distortion impact of encoding decisions, but also their long-term rate–distortion impact. In other words, optimal encoding decisions must consider the coupling between layers and the coupling across time. In many scenarios, however, it may be impractical to make joint coding decisions for all of the layers. For instance, a two layer bitstream may be coded using different encoders for the base layer and enhancement layer, each with its own autonomous control plane; or, if the same encoder is used for multiple layers, then a joint decision process, which considers the aforementioned dependencies, may be too complex. In this paper, we propose a framework for autonomous decision making in layered video coders, which decouples the decision making processes at the various layers using a novel layered Markov decision process. We illustrate how this framework can be applied to decompose the decision processes for several typical layered video coders with different dependency structures and we observe that the performance of the proposed decomposition highly depends on the ability of the layers to model each other. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...]

Error-resilient scalable compression based on distributed video coding / Mourad Ouaret in Signal processing. Image communication, Vol. 24 N° 6 (Juillet 2009) 

Public ISBD [article]  in Signal processing. Image communication > Vol. 24 N° 6 (Juillet 2009) . - pp. 437-451 Titre : Error-resilient scalable compression based on distributed video coding Type de document : texte imprimé Auteurs : Mourad Ouaret, Auteur ; Frédéric Dufaux, Auteur ; Touradj Ebrahimi, Auteur Article en page(s) : pp. 437-451 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Error-resilience  Distributed  video  coding  Scalable  coding  Codec-independent  scalability Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : Distributed Video Coding (DVC) is a new paradigm for video compression based on the information theoretical results of Slepian–Wolf (SW) and Wyner–Ziv (WZ). In this work, a performance analysis of image and video coding schemes based on DVC is presented, addressing temporal, quality and spatial scalability. More specifically, conventional coding is used to obtain a base layer while WZ coding generates the enhancement layers. At the decoder, the base layer is used to construct Side Information (SI) for the DVC decoding process. Initially, we show that the scalable DVC approach is codec-independent, which means that it is independent from the method used to encode the base layer. Moreover, the influence of the base layer quality on the overall performance of the schemes is studied. Finally, evaluation of the proposed schemes is performed in both cases, with and without transmission errors. The simulation results show that scalable DVC has a lower compression efficiency than conventional scalable coding (i.e. scalable video coding and JPEG2000 for video and image, respectively) in error-free conditions. On the other hand, the DVC-based schemes show better error resilience as they outperform conventional scalable coding in error-prone conditions. More specifically, the Rate Distortion (RD) performance of the proposed schemes for image coding is compared with respect to Reed Solomon (RS) protected JPEG2000. While the latter exhibits a cliff effect as its performance dramatically decreases after a certain error rate, the performance of the DVC-based schemes decreases in a steady way with error rate increase. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...] [article] Error-resilient scalable compression based on distributed video coding [texte imprimé] / Mourad Ouaret, Auteur ; Frédéric Dufaux, Auteur ; Touradj Ebrahimi, Auteur . - pp. 437-451. Electronique Langues : Anglais (eng) in Signal processing. Image communication > Vol. 24 N° 6 (Juillet 2009) . - pp. 437-451 Mots-clés : Error-resilience  Distributed  video  coding  Scalable  coding  Codec-independent  scalability Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : Distributed Video Coding (DVC) is a new paradigm for video compression based on the information theoretical results of Slepian–Wolf (SW) and Wyner–Ziv (WZ). In this work, a performance analysis of image and video coding schemes based on DVC is presented, addressing temporal, quality and spatial scalability. More specifically, conventional coding is used to obtain a base layer while WZ coding generates the enhancement layers. At the decoder, the base layer is used to construct Side Information (SI) for the DVC decoding process. Initially, we show that the scalable DVC approach is codec-independent, which means that it is independent from the method used to encode the base layer. Moreover, the influence of the base layer quality on the overall performance of the schemes is studied. Finally, evaluation of the proposed schemes is performed in both cases, with and without transmission errors. The simulation results show that scalable DVC has a lower compression efficiency than conventional scalable coding (i.e. scalable video coding and JPEG2000 for video and image, respectively) in error-free conditions. On the other hand, the DVC-based schemes show better error resilience as they outperform conventional scalable coding in error-prone conditions. More specifically, the Rate Distortion (RD) performance of the proposed schemes for image coding is compared with respect to Reed Solomon (RS) protected JPEG2000. While the latter exhibits a cliff effect as its performance dramatically decreases after a certain error rate, the performance of the DVC-based schemes decreases in a steady way with error rate increase. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...]

Improved BSDL-based content adaptation for JPEG 2000 and HD Photo (JPEG XR) / Wesley De Neve in Signal processing. Image communication, Vol. 24 N° 6 (Juillet 2009) 

Public ISBD [article]  in Signal processing. Image communication > Vol. 24 N° 6 (Juillet 2009) . - pp. 452-467 Titre : Improved BSDL-based content adaptation for JPEG 2000 and HD Photo (JPEG XR) Type de document : texte imprimé Auteurs : Wesley De Neve, Auteur ; Davy Van Deursen, Auteur ; Wim Van Lancker, Auteur Article en page(s) : pp. 452-467 Note générale : Electronique Langues : Anglais (eng) Mots-clés : BSDL  Content  adaptation  HD  Photo  JPEG  2000  JPEG  XR  STX  XML Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : JPEG 2000 and HD Photo (JPEG XR) enable the coding of images with several adaptivity provisions. These provisions allow taking into account the constraints of diverse usage environments. However, the actual adaptation of the coded bitstreams requires additional system complexity. This paper investigates how JPEG 2000 and HD Photo can be used in a standardized and XML-based framework for format-independent content adaptation in the compressed domain. An analysis is provided of the cost of providing adaptivity in the compressed domain, in terms of loss of coding efficiency, as well as in terms of the complexity of the format-agnostic adaptation system used. This complexity is expressed in terms of execution times, memory consumption, and file size overhead of the XML descriptions. Using the outcome of our analysis, a number of improvements are proposed that allow reducing the complexity of XML-based adaptation for JPEG 2000 and HD Photo, in particular the use of compact XML descriptions and an adaptation chain based on the Simple API for XML (SAX). Compact XML descriptions contain a minimal amount of information for the purpose of adaptation—their use is enabled by introducing an additional lightweight pre- and post-processing step in the overall adaptation chain. Our results show that editing-style operations on JPEG 2000 and HD Photo bitstreams can be executed with a feasible complexity when relying on compact XML descriptions. These editing-style operations include exploiting spatial and quality scalability, as well as interactive extraction of regions-of-interest (ROIs). However, low-level operations in the compressed domain, such as rotating an image, cannot be supported, due to the need for entropy decoding and data reordering at macroblock or codeblock level. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...] [article] Improved BSDL-based content adaptation for JPEG 2000 and HD Photo (JPEG XR) [texte imprimé] / Wesley De Neve, Auteur ; Davy Van Deursen, Auteur ; Wim Van Lancker, Auteur . - pp. 452-467. Electronique Langues : Anglais (eng) in Signal processing. Image communication > Vol. 24 N° 6 (Juillet 2009) . - pp. 452-467 Mots-clés : BSDL  Content  adaptation  HD  Photo  JPEG  2000  JPEG  XR  STX  XML Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : JPEG 2000 and HD Photo (JPEG XR) enable the coding of images with several adaptivity provisions. These provisions allow taking into account the constraints of diverse usage environments. However, the actual adaptation of the coded bitstreams requires additional system complexity. This paper investigates how JPEG 2000 and HD Photo can be used in a standardized and XML-based framework for format-independent content adaptation in the compressed domain. An analysis is provided of the cost of providing adaptivity in the compressed domain, in terms of loss of coding efficiency, as well as in terms of the complexity of the format-agnostic adaptation system used. This complexity is expressed in terms of execution times, memory consumption, and file size overhead of the XML descriptions. Using the outcome of our analysis, a number of improvements are proposed that allow reducing the complexity of XML-based adaptation for JPEG 2000 and HD Photo, in particular the use of compact XML descriptions and an adaptation chain based on the Simple API for XML (SAX). Compact XML descriptions contain a minimal amount of information for the purpose of adaptation—their use is enabled by introducing an additional lightweight pre- and post-processing step in the overall adaptation chain. Our results show that editing-style operations on JPEG 2000 and HD Photo bitstreams can be executed with a feasible complexity when relying on compact XML descriptions. These editing-style operations include exploiting spatial and quality scalability, as well as interactive extraction of regions-of-interest (ROIs). However, low-level operations in the compressed domain, such as rotating an image, cannot be supported, due to the need for entropy decoding and data reordering at macroblock or codeblock level. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...]

Adaptation–aware encryption of scalable H.264/AVC video for content security / H. Kodikara Arachchi in Signal processing. Image communication, Vol. 24 N° 6 (Juillet 2009) 

Public ISBD [article]  in Signal processing. Image communication > Vol. 24 N° 6 (Juillet 2009) . - pp. 468-483 Titre : Adaptation–aware encryption of scalable H.264/AVC video for content security Type de document : texte imprimé Auteurs : H. Kodikara Arachchi, Auteur ; X. Perramon, Auteur ; S. Dogan, Auteur Article en page(s) : pp. 468-483 Note générale : Electronique Langues : Anglais (eng) Mots-clés : End-to-end  secure  content  adaptation  Content–aware  encryption  Video  adaptation  H.264/SVC  Initialisation  vector Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : Data encryption is one of the key information security technologies used for safeguarding multimedia content from unauthorised access and manipulation in end-to-end delivery and access chains. This technology, combined with the appropriate cryptographic methods, effectively prevents the content against malicious attacks, so as to protect its authenticity as well as integrity. While encryption-based security is ensuring the authorised consumption of the multimedia content, content adaptation technologies have the primary goal of providing means for wider dissemination of the content across diverse networks, devices and users, and thus enriching user satisfaction and experience of the delivered content within a given set of usage environment constraints. Traditionally, protected contents can only be adapted at trusted adaptation engines residing between the source and end-users, since they have to be fully decrypted before performing the necessary adaptation operations. The drawback of such a process is that it significantly limits the availability and flexibility of adaptation engines applicable for adapting protected contents on the fly. Thus, this paper proposes a novel scalable H.264/advanced video coding (AVC)-compatible video encryption technique, which is also transparent to adaptation engines in an end-to-end video delivery scenario. The proposed technology relies on keeping syntax elements required for performing the adaptation operations clear (i.e., not encrypted). The effectiveness of the proposed technique has been successfully verified in scenarios, where both conventional joint scalable video model (JSVM) bit stream extracting and random packet dropping mechanisms are used. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...] [article] Adaptation–aware encryption of scalable H.264/AVC video for content security [texte imprimé] / H. Kodikara Arachchi, Auteur ; X. Perramon, Auteur ; S. Dogan, Auteur . - pp. 468-483. Electronique Langues : Anglais (eng) in Signal processing. Image communication > Vol. 24 N° 6 (Juillet 2009) . - pp. 468-483 Mots-clés : End-to-end  secure  content  adaptation  Content–aware  encryption  Video  adaptation  H.264/SVC  Initialisation  vector Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : Data encryption is one of the key information security technologies used for safeguarding multimedia content from unauthorised access and manipulation in end-to-end delivery and access chains. This technology, combined with the appropriate cryptographic methods, effectively prevents the content against malicious attacks, so as to protect its authenticity as well as integrity. While encryption-based security is ensuring the authorised consumption of the multimedia content, content adaptation technologies have the primary goal of providing means for wider dissemination of the content across diverse networks, devices and users, and thus enriching user satisfaction and experience of the delivered content within a given set of usage environment constraints. Traditionally, protected contents can only be adapted at trusted adaptation engines residing between the source and end-users, since they have to be fully decrypted before performing the necessary adaptation operations. The drawback of such a process is that it significantly limits the availability and flexibility of adaptation engines applicable for adapting protected contents on the fly. Thus, this paper proposes a novel scalable H.264/advanced video coding (AVC)-compatible video encryption technique, which is also transparent to adaptation engines in an end-to-end video delivery scenario. The proposed technology relies on keeping syntax elements required for performing the adaptation operations clear (i.e., not encrypted). The effectiveness of the proposed technique has been successfully verified in scenarios, where both conventional joint scalable video model (JSVM) bit stream extracting and random packet dropping mechanisms are used. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...]

Compressed domain indexing of scalable H.264/SVC streams / Christian Käs in Signal processing. Image communication, Vol. 24 N° 6 (Juillet 2009) 

Public ISBD [article]  in Signal processing. Image communication > Vol. 24 N° 6 (Juillet 2009) . - pp. 484-498 Titre : Compressed domain indexing of scalable H.264/SVC streams Type de document : texte imprimé Auteurs : Christian Käs, Auteur ; Henri Nicolas, Auteur Article en page(s) : pp. 484-498 Note générale : Electronique Langues : Anglais (eng) Mots-clés : H.264/SVC  Trajectory  estimation  Object  distance  estimation  Copy  detection Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : We present methods to efficiently analyze scalable, compressed H.264/scalable video coding (SVC) video streams. Relying solely on information present in the compressed stream, we estimate the global camera motion, perform motion segmentation and use a simple matching process to track moving objects over time. Object energy images are constructed in order to help resolve the problem of object correspondence during the occlusions of multiple objects. To save computing time, we analyze lower spatial layers of the stream and add higher layer information only if necessary. We draw 2-D object trajectories in the view plane of the camera and use the temporal evolution of the objects’ properties to estimate the relative distance to the camera, resulting in a pseudo 3-D representation of the trajectories. Finally, the suitability of the motion parameters to perform video retrieval/copy detection tasks is demonstrated. We therefore form two simple descriptors that are invariant to a series of transformations. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...] [article] Compressed domain indexing of scalable H.264/SVC streams [texte imprimé] / Christian Käs, Auteur ; Henri Nicolas, Auteur . - pp. 484-498. Electronique Langues : Anglais (eng) in Signal processing. Image communication > Vol. 24 N° 6 (Juillet 2009) . - pp. 484-498 Mots-clés : H.264/SVC  Trajectory  estimation  Object  distance  estimation  Copy  detection Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : We present methods to efficiently analyze scalable, compressed H.264/scalable video coding (SVC) video streams. Relying solely on information present in the compressed stream, we estimate the global camera motion, perform motion segmentation and use a simple matching process to track moving objects over time. Object energy images are constructed in order to help resolve the problem of object correspondence during the occlusions of multiple objects. To save computing time, we analyze lower spatial layers of the stream and add higher layer information only if necessary. We draw 2-D object trajectories in the view plane of the camera and use the temporal evolution of the objects’ properties to estimate the relative distance to the camera, resulting in a pseudo 3-D representation of the trajectories. Finally, the suitability of the motion parameters to perform video retrieval/copy detection tasks is demonstrated. We therefore form two simple descriptors that are invariant to a series of transformations. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...]

An integrated approach to summarization and adaptation using H.264/MPEG-4 SVC / Luis Herranz in Signal processing. Image communication, Vol. 24 N° 6 (Juillet 2009) 

Public ISBD [article]  in Signal processing. Image communication > Vol. 24 N° 6 (Juillet 2009) . - pp. 499-509 Titre : An integrated approach to summarization and adaptation using H.264/MPEG-4 SVC Type de document : texte imprimé Auteurs : Luis Herranz, Auteur ; José M. Martínez, Auteur Article en page(s) : pp. 499-509 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Video  summarization  Scalable  video  coding  MPEG-4  SVC  H.264/MPEG-4  AVC  Video  adaptation Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : The huge amount of multimedia content and the variety of terminals and networks make video summarization and video adaptation two key technologies to provide effective access and browsing. With scalable video coding, the adaptation of video to heterogeneous terminals and networks can be efficiently achieved using together a layered coding hierarchy and bitstream extraction. On the other hand, many video summarization techniques can be seen as a special case of structural adaptation. This paper describes how some of them can be modified and included in the adaptation framework of the scalable extension of H.264/AVC. The advantage of this approach is that summarization and adaptation are integrated into the same efficient framework. The utility of this approach is demonstrated with experimental results for the generation of storyboards and video skims, showing that the proposed framework can generate the adapted bitstream of the summary faster than a conventional transcoding approach. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...] [article] An integrated approach to summarization and adaptation using H.264/MPEG-4 SVC [texte imprimé] / Luis Herranz, Auteur ; José M. Martínez, Auteur . - pp. 499-509. Electronique Langues : Anglais (eng) in Signal processing. Image communication > Vol. 24 N° 6 (Juillet 2009) . - pp. 499-509 Mots-clés : Video  summarization  Scalable  video  coding  MPEG-4  SVC  H.264/MPEG-4  AVC  Video  adaptation Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : The huge amount of multimedia content and the variety of terminals and networks make video summarization and video adaptation two key technologies to provide effective access and browsing. With scalable video coding, the adaptation of video to heterogeneous terminals and networks can be efficiently achieved using together a layered coding hierarchy and bitstream extraction. On the other hand, many video summarization techniques can be seen as a special case of structural adaptation. This paper describes how some of them can be modified and included in the adaptation framework of the scalable extension of H.264/AVC. The advantage of this approach is that summarization and adaptation are integrated into the same efficient framework. The utility of this approach is demonstrated with experimental results for the generation of storyboards and video skims, showing that the proposed framework can generate the adapted bitstream of the summary faster than a conventional transcoding approach. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...]

An efficient optimisation scheme for scalable surveillance centric video communications / Naeem Ramzan in Signal processing. Image communication, Vol. 24 N° 6 (Juillet 2009) 

Public ISBD [article]  in Signal processing. Image communication > Vol. 24 N° 6 (Juillet 2009) . - pp. 510-523 Titre : An efficient optimisation scheme for scalable surveillance centric video communications Type de document : texte imprimé Auteurs : Naeem Ramzan, Auteur ; Toni Zgaljic, Auteur ; Ebroul Izquierdo, Auteur Article en page(s) : pp. 510-523 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Surveillance  centric  coding  Scalable  video  coding  Transmission  of  scalable  video Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : State-of-the-art coders have been optimised over years according to the needs of the broadcasting industry. There are however key applications of coding technology whose challenges and requirements substantially differ from broadcasting. One of these key applications is surveillance. In this paper an efficient approach for surveillance centric joint source and channel coding is proposed. Contrasting conventional coders, the proposed system has been developed according to the requirements of surveillance application scenarios. It aims at achieving bit-rate optimisation and adaptation of surveillance videos for storing and transmission purposes. In the proposed approach the encoder communicates with a video content analysis (VCA) module that detects events of interests in video captured by CCTV. Bit-rate optimisation and adaptation is achieved by exploiting the scalability properties of the employed codec. Temporal segments containing events relevant to surveillance application are encoded using high spatio-temporal resolution and quality while the portions irrelevant from the surveillance standpoint are encoded at low spatio-temporal resolution and/or quality. Furthermore, the approach jointly optimises the bit allocation between the wavelet-based scalable video coder and forward error correction codes. The forward error correction code is based on the product code constituting of LDPC codes and turbo codes. Turbo codes show good performance at high error rates region but LDPC outperforms turbo codes at low error rates. Therefore, the concatenation of LDPC and TC enhances the performance at both low and high signal-to-noise (SNR) ratios. The proposed approach minimises the distortion of reconstructed video, subject to constraint on the overall transmission bit-rate budget. Experimental results clearly demonstrate the efficiency and suitability of the proposed approach in surveillance applications. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...] [article] An efficient optimisation scheme for scalable surveillance centric video communications [texte imprimé] / Naeem Ramzan, Auteur ; Toni Zgaljic, Auteur ; Ebroul Izquierdo, Auteur . - pp. 510-523. Electronique Langues : Anglais (eng) in Signal processing. Image communication > Vol. 24 N° 6 (Juillet 2009) . - pp. 510-523 Mots-clés : Surveillance  centric  coding  Scalable  video  coding  Transmission  of  scalable  video Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : State-of-the-art coders have been optimised over years according to the needs of the broadcasting industry. There are however key applications of coding technology whose challenges and requirements substantially differ from broadcasting. One of these key applications is surveillance. In this paper an efficient approach for surveillance centric joint source and channel coding is proposed. Contrasting conventional coders, the proposed system has been developed according to the requirements of surveillance application scenarios. It aims at achieving bit-rate optimisation and adaptation of surveillance videos for storing and transmission purposes. In the proposed approach the encoder communicates with a video content analysis (VCA) module that detects events of interests in video captured by CCTV. Bit-rate optimisation and adaptation is achieved by exploiting the scalability properties of the employed codec. Temporal segments containing events relevant to surveillance application are encoded using high spatio-temporal resolution and quality while the portions irrelevant from the surveillance standpoint are encoded at low spatio-temporal resolution and/or quality. Furthermore, the approach jointly optimises the bit allocation between the wavelet-based scalable video coder and forward error correction codes. The forward error correction code is based on the product code constituting of LDPC codes and turbo codes. Turbo codes show good performance at high error rates region but LDPC outperforms turbo codes at low error rates. Therefore, the concatenation of LDPC and TC enhances the performance at both low and high signal-to-noise (SNR) ratios. The proposed approach minimises the distortion of reconstructed video, subject to constraint on the overall transmission bit-rate budget. Experimental results clearly demonstrate the efficiency and suitability of the proposed approach in surveillance applications. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...]

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