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Despite theorems predicting that Distributed Video Coding can achieve the same performance as traditional predictive video coding schemes, the coding efficiency of practical architectures is still far from these bounds. This is attributed to the poor Side Information (SI) estimated at the decoder and to the inability of the channel codes to recover the source at the Slepian-Wolf (SW) limits. This...
The exponential growth of video traffic is expected to reach 62% of the global Internet traffic by the end of 2015 [1]. This presents as a significant challenge for the television service providers who need to employ networking technologies to monitor specific Quality of Service (QoS) parameters such as packet loss rate, jitter and delay, to ensure an acceptable level of quality. However, recent research...
The multimedia signal processing community has recently identified the need to design depth map compression algorithms which preserve depth discontinuities in order to improve the rendering quality of virtual views for Free Viewpoint Video (FVV) services. This paper adopts contour detection with surround suppression on the color video to approximate the foreground edges present in the depth image...
The Distributed Video Coding (DVC) paradigm offers lightweight encoding capabilities which are suitable for devices with limited computational resources. Moreover, DVC techniques can theoretically achieve the same coding efficiency as the traditional video coding schemes which employ more complex encoders. However, the performance of practical DVC architectures is still far from such theoretical bounds,...
Bandwidth-limited channels demand the transmission of the per-pixel depth maps with the texture data to provide immersive 3D video services that allow arbitrary 3D viewpoint reconstruction. This auxiliary depth data offers geometric information, which together with the multi-view and epipolar geometries, can be exploited during 3D video coding to calculate geometric positions for the search areas...
The Distributed Video Coding (DVC) paradigm is suitable for devices which have limited encoding capabilities. However, it is characterized by excessive decoding delays which compromise their application for time constrained services. This limitation can be mitigated by adopting parallel DVC architectures. Yet, the traditional Gray-code or binary-code representations have a non-uniform distribution...
Recent advances in multimedia technology have paved the way to the development of several applications, including digital TV broadcasting, mobile TV, mobile gaming and telemedicine. Nonetheless, real time multimedia services still provide challenges as reliable delivery of the content cannot be guaranteed. The video compression standards incorporate error resilient mechanisms to mitigate this effect...
This paper presents a novel depth image compression algorithm for both 3D Television (3DTV) and Free Viewpoint Television (FVTV) services. The proposed scheme adopts the K-means clustering algorithm to segment the depth image into K segments. The resulting segmented image is losslessly compressed and transmitted to the decoder. The depth image is then compressed using a bi-modal block encoder, where...
The feasible implementation of immersive 3D video systems entails the need for a substantial reduction in the amount of image information necessary for representation. Multiview image rendering algorithms based on depth data have radically reduced the number of images required to reconstruct a 3D scene. Nonetheless, the compression of depth maps still poses several challenges due to the particular...
The motion vectors take a large portion of the H.264/AVC encoded bitstream. This video coding standard employs predictive coding to minimize the amount of motion vector information to be transmitted. However, the motion vectors still accounts for around 40% of the transmitted bitstream, which suggests further research in this area. This paper presents an algorithm which employs a feature selection...
The Multi-view Video Coding (MVC) standard was developed for efficient encoding of multi-view videos. Part of it requires the calculation of both disparity and motion estimations using a bi-prediction structure. These estimations involve an exhaustive search for the optimal compensation vectors from multiple forward and backward reference frames which, while being very efficient in terms of compression,...
The persistent improvements witnessed in multimedia production have considerably augmented users demand for immersive 3D systems. Expedient implementation of this technology however, entails the need for significant reduction in the amount of information required for representation. Depth image-based rendering algorithms have considerably reduced the number of images necessary for 3D scene reconstruction,...
Motion and disparity estimations are employed in Multi-view Video Coding (MVC) to remove redundancies present between temporal and different viewpoint frames, respectively, in both the color and the depth multi-view videos. These constitute the major computational expensive tasks of the video encoder, as iterative search for the optimal mode and its appropriate compensation vectors is employed to...
Driver fatigue is one of the leading causes of traffic accidents. This paper presents a real-time non-intrusive fatigue monitoring system which exploits the driver's facial expression to detect and alert fatigued drivers. The presented approach adopts the Viola-Jones classifier to detect the driver's facial features. The correlation coefficient template matching method is then applied to derive the...
Immersive 3D video services demand the transmission of the viewpoints' depth map together with the texture multiview video to allow arbitrary reconstruction of intermediate viewpoints required for free-view navigation and 3D depth perception. The Multi-view Video Coding (MVC) standard is generally used to encode these auxiliary depth maps and since their estimation process is highly computational...
Over the past few decades, Distributed Video Coding (DVC) has been considered as a compression paradigm suitable for applications which require simple encoding. Yet, the performance obtained with practical architectures is still far from the theoretical bound, mainly due to the inaccurate Side Information (SI) predicted at the decoder. The work presented in this paper tries to improve the correlation...
Distributed Video Coding (DVC) is a coding paradigm which shifts the major computational intensive tasks from the encoder to the decoder. Temporal correlation is exploited at the decoder by predicting the Wyner-Ziv (WZ) frames from the adjacent key frames. Compression is then achieved by transmitting just the parity information required to correct the predicted frame and recover the original frame...
Disparity estimation is used in Multi-view Video Coding (MVC) to remove the inter-view redundancies present in both color and depth multi-view video sequences. The standard H.264/MVC achieves high compression efficiency by deriving the optimal disparity vector through the exhaustive calculation of the Rate-Distortion cost function for all the possible search points. This makes disparity estimation...
Distributed Video Coding (DVC) is a coding paradigm where video statistics are exploited, partially or totally, at the decoder. The performance of such a codec depends on the accuracy of the soft-input information estimated at the decoder, which is affected by the quality of the side information (SI) and the dependency model. This paper studies the discrepancies between the bit planes of the Wyner-Ziv...
The Multi-view Video Coding (MVC) technique provides significantly better coding efficiency compared to simulcast transmission of different camera view-points. This is done by exploiting both motion and disparity compensation techniques to compress the different view-point videos. This paper proposes a more efficient MVC technique that transmits the optimally selected compensation replacements with...
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