Made available in DSpace on 2016-03-22T17:26:22Z (GMT). No. of bitstreams: 1 DMII_AndreMarcel.pdf: 2907967 bytes, checksum: 5f3911468dd5affdd2020316f31ee238 (MD5) Previous issue date: 2009-12-11 / The increasing use of digital video on the Internet, devices and also in mobile digital TV has lead to an increasing interest for research in this area, from both industry and academia. This work follows this trend by proposing the investigation of the main aspects of digital video, video compression and also of the H.264/AVC video compression for the implementation of performance efficient dedicated architectures for some modules of the H.264/AVC encoder. In particular, this work presents some architectural alternatives for the increase of performance of two modules of the H.264/AVC, which are: T Module (composed by the Forward Hadamard and Discrete Cosine Transforms) and Motion Estimation (ME). For the implementation of these modules the use of techniques to the increase of performance has been considered, such as the use of efficient adders and pipeline. This efficient adders presents high use of hardware features. Thus, the implemented architectures in this work presented these characteristics too. The main aspect presented by the implemented modules is a large number of arithmetic operations of addition and subtraction for their processing. Thus, the motivation of this work is the increase of performance of these modules, from the use of efficient adder/subtractor circuits that are present in literature. In particular, 4:2, 8:2 and 16:2 adder compressors that perform the simultaneous addition of 4, 8 and 16 operands, respectively, with no penalties in area and the critical path are used. The architectures were described in VHDL and targeted to ASIC technology. The validation of the circuits and the obtained results were performed by using Leonardo Spectrum tool from Mentor Graphics. Comparisons against the solutions of the literature were done and the main results show that the architectures proposed in this work are more efficient. Significant gains in performance are achievable using our solutions for both Forward Transforms and Motion Estimation architectures / A crescente utilização de vídeos digitais na Internet, em dispositivos móveis e também na TV digital faz com que haja um interesse crescente em pesquisas nesta área, tanto na indústria quanto no meio acadêmico. Este trabalho segue esta tendência e tem como proposta estudar aspectos de vídeo digital, compressão de vídeo e também do padrão H.264/AVC de compressão de vídeo para a implementação de arquiteturas dedicadas eficientes em desempenho, isto é, com elevada frequência de operação, dos módulos do codificador do padrão H.264/AVC. Em particular, este trabalho apresenta algumas alternativas arquiteturais para aumento de desempenho de dois módulos do padrão H.264/AVC, que são: Módulo T (composto pelas Transformadas Diretas Transformadas Hadamard e Transformada Discreta do Coseno) e Estimação de Movimento (ME). A implementação destes módulos foi realizada utilizando técnicas para o aumento de desempenho, tais como o uso de somadores eficientes e pipeline. Uma característica dos somadores eficientes utilizados neste trabalho é o uso elevado de recursos de hardware. Assim, as arquiteturas implementadas neste trabalho também apresentaram esta característica. Os módulos implementados apresentam como principal característica um elevado número de operações aritméticas de soma e subtração para o seu processamento. Desta forma, a motivação deste trabalho consiste em aumentar o desempenho destes módulos, a partir da utilização de circuitos somadores/subtratores eficientes presentes na literatura. Em particular, são utilizados circuitos somadores compressores 4:2, 8:2 e 16:2, pois estes realizam a soma simultânea de 4, 8 e 16 operandos, respectivamente, sem penalidades em área e no caminho crítico. As arquiteturas foram descritas em VHDL e direcionadas para tecnologia ASIC, a validação e resultados foram obtidos através da ferramenta Leonardo Spectrum da Mentor Graphics. Para os estudos de caso utilizados neste trabalho (Transformadas Diretas e Estimação de Movimento), foram feitas comparações com soluções apresentadas na literatura e os resultados mostram que as arquiteturas implementadas neste trabalho obtiveram significativos ganhos em desempenho, quando comparadas com soluções apresentadas na literatura

Les progrès réalisés en systèmes micro-électro-mécaniques couplés avec leur convergence vers les systèmes de communication sans fil, ont permis l'émergence des réseaux de capteurs sans fil (RCSF). Les contraintes de ces réseaux font que tous les efforts soient fournis pour proposer des solutions économes en énergie. Avec les récents développements des technologies CMOS, des capteurs d'images à faible coût ont été développés. En conséquence, un nouveau dérivé des RCSF, qui sont les Réseaux de Capteurs Vidéo Sans Fil (RCVSF), a été proposé. La particularité des données vidéo ainsi que les contraintes inhérentes aux nœuds ont introduit de nouveaux défis. Dans cette thèse, nous proposons deux solutions basées sur l'approche inter-couches pour la livraison de la vidéo sur les RCVSF. La première solution propose un nouveau schéma de compression vidéo adaptatif, efficace en énergie et basé sur la norme de compression vidéo H.264/AVC. Le flux vidéo est ensuite géré par une version améliorée du protocole MMSPEED que nous proposons et notons EQBSA-MMSPEED. Les résultats des simulations montrent que la durée de vie du réseau est étendue de 33%, tout en améliorant la qualité du flux vidéo reçu de 12%. Dans la deuxième solution, nous enrichissons le schéma de compression de modèles mathématiques pour prévoir la consommation d'énergie et la distorsion de l'image lors des phases d'encodage et de transmission. Le flux vidéo est géré par un nouveau protocole de routage efficace en énergie et à fiabilité améliorée noté ERMM. Comparée à une approche basique, cette solution réalise une extension de la durée de vie du réseau de 15%, tout en améliorant la qualité du flux vidéo reçu de 35%. / Thanks to the valuable advances in Micro Electro-Mechanical Systems coupled with their convergence to wireless communication systems, the Wireless Sensor Networks (WSN). In the WSN context, all the efforts are made in order to propose energy-efficient solutions. With the recent developments in CMOS technology, low-cost imaging sensors have been developed. As a result, a new derivative of the WSN, which is the Wireless Video Sensor Network (WVSN), has been proposed. The particularities of the video data as well as the inherent constraints of the nodes have introduced new challenges. In this thesis, we propose two cross-layer based solutions for video delivery over the WVSN. The first solution proposes a new energy efficient and adaptive video compression scheme dedicated to the WVSNs, based on the H.264/AVC video compression standard. The video stream is then handled by an enhanced version of MMSPEED protocol, that we propose and note EQBSA-MMSPEED. Performance evaluation shows that the lifetime of the network is extended by 33%, while improving the video quality of the received stream by 12%. In the second solution, we enrich our compression scheme with mathematical models to predict the energy consumption and the video distortion during the encoding and the transmission phases. The video stream is then handled by a novel energy efficient and improved reliability routing protocol, that we note ERMM. Compared to a basic approach, this solution is extending the network lifetime by 15%, while improving the quality of the received video stream by 35%.

This thesis is concerned with maximizing the coding efficiency, random accessibility and visual performance of scalable compressed video. The unifying theme behind this work is the use of finely embedded localized coding structures, which govern the extent to which these goals may be jointly achieved. The first part focuses on scalable volumetric image compression. We investigate 3D transform and coding techniques which exploit inter-slice statistical redundancies without compromising slice accessibility. Our study shows that the motion-compensated temporal discrete wavelet transform (MC-TDWT) practically achieves an upper bound to the compression efficiency of slice transforms. From a video coding perspective, we find that most of the coding gain is attributed to offsetting the learning penalty in adaptive arithmetic coding through 3D code-block extension, rather than inter-frame context modelling. The second aspect of this thesis examines random accessibility. Accessibility refers to the ease with which a region of interest is accessed (subband samples needed for reconstruction are retrieved) from a compressed video bitstream, subject to spatiotemporal code-block constraints. We investigate the fundamental implications of motion compensation for random access efficiency and the compression performance of scalable interactive video. We demonstrate that inclusion of motion compensation operators within the lifting steps of a temporal subband transform incurs a random access penalty which depends on the characteristics of the motion field. The final aspect of this thesis aims to minimize the perceptual impact of visible distortion in scalable reconstructed video. We present a visual optimization strategy based on distortion scaling which raises the distortion-length slope of perceptually significant samples. This alters the codestream embedding order during post-compression rate-distortion optimization, thus allowing visually sensitive sites to be encoded with higher fidelity at a given bit-rate. For visual sensitivity analysis, we propose a contrast perception model that incorporates an adaptive masking slope. This versatile feature provides a context which models perceptual significance. It enables scene structures that otherwise suffer significant degradation to be preserved at lower bit-rates. The novelty in our approach derives from a set of "perceptual mappings" which account for quantization noise shaping effects induced by motion-compensated temporal synthesis. The proposed technique reduces wavelet compression artefacts and improves the perceptual quality of video.

<p>A channel change in digital television is usually conducted at a reference frame, which are sent at certain intervals. A higher compression ratio could however be obtained by sending reference frames at arbitrary long intervals. This would on the other hand increase the average channel change time for the end user. This thesis investigates various approaches for reducing the average channel change time while using arbitrary long intervals between reference frames, and presents an implementation and evaluation of one of these methods, called Baydec.</p><p>The approach of Baydec for solving the channel switch problem is to statistically estimate what the original image looked like, starting with an incoming P-frame and estimate an image between the original and current image. Baydec gathers statistical data from typical video sequences and calculates expected likelihood for estimation. Further on it uses the Simulated Annealing search method to maximise the likelihood function.</p><p>This method is more general than the requirements of this thesis. It is not only applicable to channel switches between video streams, but can also be used for random access in general. Baydec could also be used if an I-frame is dropped in a video stream.</p><p>However, Baydec has so far shown only theoretical result, but very small visual improvements. Baydec produces images with better PSNR than without the method in some cases, but the visual impression is not better than for the motion compensated residual images. Some examples of future work to improve Baydec is also presented.</p>

L'objectif de cette thèse est le déploiement et l'évaluation d'une plate-forme de télé-échographie mobile, utilisée pour fournir un diagnostic et des soins à distance dans des milieux médicalement isolés. La plateforme intègre de nouveaux concepts qui permettent de l’utilisation de la télé-échographie robotisée sur les réseaux sans fil 3G, 4G et 5G pour satisfaire au transfert de qualité des vidéos ultrasonores pour un diagnostic médical robuste. Ce travail contribue au domaine des Sciences et Technologies de l'Information et de la Communication appliquées au secteur de la santé et en particulier à la robotique médicale téléopérée. Les principales contributions de la thèse sont : I. Un état de l’art des systèmes télé-robotiques appliqués au médical menée sur la base de publications écrites entre 2004 et 2016, II. L'évaluation objective et subjective (clinique) de la qualité vidéo a démontré que les normes H.264/AVC et HEVC peuvent atteindre une qualité vidéo sans perte de diagnostic à des débits (1024 et 2048 Kbps) bien en deçà des débits de données supportés par les réseaux 4G. Les normes de codage vidéo antérieures (Mpeg-4, Mpeg-2) ne peuvent pas être utilisées pour le diagnostic clinique à ces débits car elles présentent une perte d'information pour le diagnostic médical, III. Les experts médicaux ont apprécié la réactivité dynamique mécanique de la plate-forme en raison du faible délai présenté par les canaux LTE. La limitation la plus importante soulevée par l'expert médical, empêchant une évaluation globale clinique favorable au diagnostic, était le positionnement initial du robot sur le corps du patient et son déplacement vers l'obtention d’une échographie cardiaque, Les résultats fournissent une forte indication que la plate-forme télé-échographie robotisée peut être utilisée pour fournir un diagnostic fiable et à distance sur les réseaux sans fil émergents 4G et au-delà. / The objective of this Thesis was the deployment and evaluation of an end-to-end mobile tele-echography platform used to provide remote diagnosis and care within medically isolated settings. The platform integrates new concepts that enable robotized tele-echography over commercially available 4G and beyond mobile networks for rendering diagnostically robust medical ultrasound video. It contributes to the field of Information and Communication technologies applied in the healthcare sector. The main contributions of the Thesis are: I. A systematic review on the state of the art in medical telerobotic systems was conducted based on publications of the last decade, and more specifically between the years 2004 to 2016. II. Both objective and subjective (clinical) video quality assessment demonstrated that H.264/AVC and HEVC standards can achieve diagnostically-lossless video quality at bitrates (1024 and 2048 Kbps) well within the LTE supported data rates. Earlier video coding standards (Mpeg-4 & Mpeg-2) cannot be employed for clinical diagnosis at these rates as they present loss of clinical information.III. Medical experts highly appreciated the proposed platform’s mechanical dynamic responsiveness due to the low end-to-end delay (latency) facilitated by LTE-channels. The most important limitation raised by the medical expert and prevented higher overall rating and ultimately clinical QoE was the robot initial positioning on the patient’s body and navigation towards obtaining the cardiac ultrasound. IV. Results provides a strong indication that the proposed robotized tele-echography platform can be used to provide reliable, remote diagnosis over emerging 4G and beyond wireless networks.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-05-07T15:46:17Z No. of bitstreams: 1 LUIZ TEIXEIRA MACHADO NETO - DISSERTAÇÃO PPGCC 2015..pdf: 936539 bytes, checksum: 75e4ab7774a9d4c965e23ec09254fc86 (MD5) / Made available in DSpace on 2018-05-07T15:46:17Z (GMT). No. of bitstreams: 1 LUIZ TEIXEIRA MACHADO NETO - DISSERTAÇÃO PPGCC 2015..pdf: 936539 bytes, checksum: 75e4ab7774a9d4c965e23ec09254fc86 (MD5) Previous issue date: 2015-03-01 / A utilização de serviços de streaming cresceu bastante nos últimos anos, por meio de sistemas como Youtube, Hulu, Netflix, Vimeo, etc. Utilizando o stream, os vídeos são transmitidos e exibidos em tempo real e em qualquer lugar do mundo por meio da internet. Muitosusuáriosdestessistemasosutilizamemsuaresidênciaondeébastante comumencontrarumaredesemfio(devidoàmobilidadequesepodealcançarpormeio deste tipo de rede). Apesar de mais mobilidade, uma rede sem fio está mais suscetível a interferências do que a rede cabeada e, por isso, um vídeo pode ter sua imagem degradada com mais facilidade. Neste trabalho, é avaliada a transmissão de vídeos via stream para descobrir se o vídeo realmente é degradado pela transmissão; se tipos de conteúdos diferentes afetam a qualidade do vídeo recebido; e se de acordo com o padrão de compressão utilizado, é possível observar melhorias na qualidade do vídeo recebido. Por meio de uma abordagem experimental com um design de experimentos fatorial completo, foram feitas transmissões de vídeos utilizando o H.264, o HEVC e o MPEG-4; padrões mais utilizados atualmente. Além de definir os padrões, foram definidas outras variáveis: porcentagem de ocupação do canal de transmissão (com o objetivo de avaliar a degradação dos vídeos de acordo com a competição que a rede está sofrendo); potência do sinal de transmissão (com o objetivo de avaliar o impacto da qualidade do sinal da rede no vídeo recebido); quantidade de movimento no vídeo (para avaliar se a quantidade de movimento que o vídeo exibe impacta na sua qualidade). Nos experimentos, foi utilizado um ambiente residencial que conta as interferências de outras redes, exatamente como pode acontecer em um ambiente real. Para definir as porcentagens de ocupação, foram realizados experimentos para medição da capacidade máxima de transmissão da rede de testes. Em se tratando da quantidade de movimento, foi necessário fazer uma classificação prévia dos vídeos de acordo com características espaciais e temporais de cada vídeo. Os vídeos foram separados em três categorias e dentro dessas categorias, três vídeos foram escolhidos aleatoriamente para participar dos experimentos. Os resultados mostram que o HEVC obteveamelhormédiaparaasmétricasdequalidadedevídeoescolhidas, sendoocodec que menos perde qualidade numa transmissão sem fio. Também foi possível observar que a quantidade de movimento foi o parâmetro que mais influenciou na qualidade do vídeos nos experimentos realizados. / The use of streaming services has grown significantly in recent years, through systems such as Youtube, Hulu, Netflix, Vimeo, etc. Using the stream, videos are transmitted and displayed in real time and from anywhere in the world via the Internet. Many users of these systems use the same in their homes where it is quite common to find a wireless network (due to the mobility we can achieve through this type of computer network). In spite of having more mobility, a wireless network is more susceptible to interference than the wired network so a video can have its picture degraded more easily just because it is transmitted over a wireless network. We evaluate the transmission of videos via stream to find out whether the video is actually degraded by transmission; if different types of content affect the quality of the received video; and if there are compression standarts (H.264 and MPEG-4 HEVC, the most currently used) which ensure a better received video quality. Through an experimental approach with a design of full factorial experiments, several transmissions of videos were made in the three chosen standarts. In addition to defining the standarts, other variables were defined as: transmission channel occupancy percentage (in order to evaluate the degradation of videos according to occupation); power transmission signal (in order to assess the impact of network signal quality in the video received); amount of motion in the video (to evaluate whether the amount of motion the video displays impacts on its quality). For the experiments we used a residential environment that has all the interference from other networks, just as it can happen in a real environment. To set the occupancy percentages, experiments were performed to measure the maximum transmission capacity of the test network. Concerning the quantity of movement, it was necessary to make a preliminary classification of videos according to spatial and temporal characteristics of each one. The videos were separated into three categories and within these categories, three videos were chosen at random to participate in the experiments. The results show that the HEVC achieved the highest average for quality metricsofthechosenvideos,andthecodecistheonethatloseslessqualityinawireless transmission. The amount of movement affects the quality of the received video, and the greater the amount of motion, the bigger the loss of image quality.

A channel change in digital television is usually conducted at a reference frame, which are sent at certain intervals. A higher compression ratio could however be obtained by sending reference frames at arbitrary long intervals. This would on the other hand increase the average channel change time for the end user. This thesis investigates various approaches for reducing the average channel change time while using arbitrary long intervals between reference frames, and presents an implementation and evaluation of one of these methods, called Baydec. The approach of Baydec for solving the channel switch problem is to statistically estimate what the original image looked like, starting with an incoming P-frame and estimate an image between the original and current image. Baydec gathers statistical data from typical video sequences and calculates expected likelihood for estimation. Further on it uses the Simulated Annealing search method to maximise the likelihood function. This method is more general than the requirements of this thesis. It is not only applicable to channel switches between video streams, but can also be used for random access in general. Baydec could also be used if an I-frame is dropped in a video stream. However, Baydec has so far shown only theoretical result, but very small visual improvements. Baydec produces images with better PSNR than without the method in some cases, but the visual impression is not better than for the motion compensated residual images. Some examples of future work to improve Baydec is also presented.

Intra-prediction is a method for coding standalone frames in video coding. Until now, this has mainly been done using linear formulae. Using an Artificial Neural Network (ANN) may improve the prediction accuracy, leading to improved coding efficiency. In this degree project, Fully Connected Networks (FCN) and Convolutional Neural Networks (CNN) were used for intra-prediction. Experiments were done on samples from different image sizes, block sizes, and block contents, and their effect on the results were compared and discussed. The results show that ANN methods have the potential to perform better or on par with the video coder High Efficiency Video Coding (HEVC) in the intra-prediction task. The proposed ANN designs perform better on smaller block sizes, but different designs could lead to better performance on larger block sizes. It was found that training one network for each HEVC mode and using the most suitable network to predict each block improved performance of the ANN approach. / Intra-prediktion är en metod för kodning av stillbilder i videokodning. Hittills har detta främst gjorts med hjälp av linjära formler. Användning av artificialla neuronnät (ANN) skulle kunna öka prediktionsnoggrannheten och ge högre effektivitet vid kodning. I detta examensarbete användes fully connected networks (FCN) och convolutional neural networks (CNN) för att utföra intra-prediktion. Experiment gjordes på prover från olika bildstorlekar, blockstorlekar och blockinnehåll, och de olika parametrarnas effekt på resultaten jämfördes och diskuterades. Resultaten visar att ANN-metoder har potential att prestera bättre eller lika bra som videokodaren High Efficiency Video Coding (HEVC) för intra-prediktion. De föreslagna ANN-designerna presterar bättre på mindre blockstorlekar, men andra ANN-designs skulle kunna ge bättre prestanda för större blockstorlekar. Det konstaterades att prestandan för ANN-metoderna kunde ökas genom att träna ett nätverk för varje HEVC-mode och använda det mest passande nätverket för varje block.

Field Programmable Gate Array (FPGA) devices offer a suitable platform for survivable hardware architectures in mission-critical systems. In this dissertation, active dynamic redundancy-based fault-handling techniques are proposed which exploit the dynamic partial reconfiguration capability of SRAM-based FPGAs. Self-adaptation is realized by employing reconfiguration in detection, diagnosis, and recovery phases. To extend these concepts to semiconductor aging and process variation in the deep submicron era, resilient adaptable processing systems are sought to maintain quality and throughput requirements despite the vulnerabilities of the underlying computational devices. A new approach to autonomous fault-handling which addresses these goals is developed using only a uniplex hardware arrangement. It operates by observing a health metric to achieve Fault Demotion using Recon- figurable Slack (FaDReS). Here an autonomous fault isolation scheme is employed which neither requires test vectors nor suspends the computational throughput, but instead observes the value of a health metric based on runtime input. The deterministic flow of the fault isolation scheme guarantees success in a bounded number of reconfigurations of the FPGA fabric. FaDReS is then extended to the Priority Using Resource Escalation (PURE) online redundancy scheme which considers fault-isolation latency and throughput trade-offs under a dynamic spare arrangement. While deep-submicron designs introduce new challenges, use of adaptive techniques are seen to provide several promising avenues for improving resilience. The scheme developed is demonstrated by hardware design of various signal processing circuits and their implementation on a Xilinx Virtex-4 FPGA device. These include a Discrete Cosine Transform (DCT) core, Motion Estimation (ME) engine, Finite Impulse Response (FIR) Filter, Support Vector Machine (SVM), and Advanced Encryption Standard (AES) blocks in addition to MCNC benchmark circuits. A iii significant reduction in power consumption is achieved ranging from 83% for low motion-activity scenes to 12.5% for high motion activity video scenes in a novel ME engine configuration. For a typical benchmark video sequence, PURE is shown to maintain a PSNR baseline near 32dB. The diagnosability, reconfiguration latency, and resource overhead of each approach is analyzed. Compared to previous alternatives, PURE maintains a PSNR within a difference of 4.02dB to 6.67dB from the fault-free baseline by escalating healthy resources to higher-priority signal processing functions. The results indicate the benefits of priority-aware resiliency over conventional redundancy approaches in terms of fault-recovery, power consumption, and resource-area requirements. Together, these provide a broad range of strategies to achieve autonomous recovery of reconfigurable logic devices under a variety of constraints, operating conditions, and optimization criteria.

Vision systems have become ubiquitous. They are used for traffic monitoring, elderly care, video conferencing, virtual reality, surveillance, smart rooms, home automation, sport games analysis, industrial safety, medical care etc. In most vision systems, the data coming from the visual sensor(s) is processed before transmission in order to save communication bandwidth or achieve higher frame rates. The type of data processing needs to be chosen carefully depending on the targeted application, and taking into account the available memory, computational power, energy resources and bandwidth constraints. In this dissertation, we investigate how a vision system should be built under practical constraints. First, this system should be intelligent, such that the right data is extracted from the video source. Second, when processing video data this intelligent vision system should know its own practical limitations, and should try to achieve the best possible output result that lies within its capabilities. We study and improve a wide range of vision systems for a variety of applications, which go together with different types of constraints. First, we present a modulo-PCM-based coding algorithm for applications that demand very low complexity coding and need to preserve some of the advantageous properties of PCM coding (direct processing, random access, rate scalability). Our modulo-PCM coding scheme combines three well-known, simple, source coding strategies: PCM, binning, and interpolative coding. The encoder first analyzes the signal statistics in a very simple way. Then, based on these signal statistics, the encoder simply discards a number of bits of each image sample. The modulo-PCM decoder recovers the removed bits of each sample by using its received bits and side information which is generated by interpolating previous decoded signals. Our algorithm is especially appropriate for image coding. / Morbee, M. (2011). Optimized information processing in resource-constrained vision systems. From low-complexity coding to smart sensor networks [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/12126