Current Issue : April - June Volume : 2014 Issue Number : 2 Articles : 5 Articles
In many digital video applications, video sequences suffer from jerky movements between successive frames. In this paper, an\r\nintegrated general-purpose stabilization method is proposed, which extracts the information from successive frames and removes\r\nthe translation and rotation motions that result in undesirable effects. The scheme proposed starts with computation of the optical\r\nflow between consecutive video frames and an affine motion model is adopted in conjunction with the optical flow field obtained\r\nto estimate objects or camera motions using the Horn-Schunck algorithm. The estimatedmotion vectors are then used by amodelfitting\r\nfilter to stabilize and smooth video sequences. Experimental results demonstrate that the proposed scheme is efficient due to\r\nits simplicity and provides good visual quality in terms of the global transformation fidelity measured by the peak-signal-noise-ratio....
We present a framework for cross-layer optimized real time multiuser encoding of video using a single layer H.264/AVC and\r\ntransmission over MIMO wireless channels. In the proposed cross-layer adaptation, the channel of every user is characterized by\r\nthe probability density function of its channel mutual information and the performance of the H.264/AVC encoder is modeled\r\nby a rate distortion model that takes into account the channel errors. These models are used during the resource allocation of\r\nthe available slots in a TDMA MIMO communication system with capacity achieving channel codes. This framework allows for\r\nadaptation to the statistics of the wireless channel and to the available resources in the system and utilization of the multiuser\r\ndiversity of the transmitted video sequences. We show the effectiveness of the proposed framework for video transmission over\r\nRayleigh MIMO block fading channels, when channel distribution information is available at the transmitter....
The paper investigates the capabilities of Parlay X Web Services for Policy and Charging Control (PCC) in managing all Internetprotocol-\r\nbased multimedia networks (IMSs). PCC is one of the core features of evolved packet networks. It comprises flow-based\r\ncharging including charging control and online credit control, gating control, and Quality of Service (QoS) control. Based on\r\nthe analysis of requirements for PCC, the functionality for open access to QoS management and advanced charging is identified.\r\nParlay X Web Services are evaluated for the support of PCC, and some enhancements are suggested. Implementation aspects\r\nare discussed, and Parlay X interfaces are mapped onto IMS control protocols. Use cases of Parlay X Web Services for PCC are\r\npresented....
In the field ofmultimedia, very little attention is given to the activities involved in the preservation of audio documents. At the same\r\ntime, more and more archives storing audio and video documents face the problem of obsolescing and degrading media, which\r\ncould largely benefit from the instruments and the methodologies of research in multimedia. This paper presents the methodology\r\nand the results of the Italian project REVIVAL, aimed at the development of a hardware/software platform to support the active\r\npreservation of the audio collection of the Fondazione Arena di Verona, one of the finest in Europe for the operatic genre, with a\r\nspecial attention on protocols and tools for quality control. On the scientific side, the most significant objectives achieved by the\r\nproject are (i) the setup of a working environment inside the archive, (ii) the knowledge transfer to the archival personnel, (iii) the\r\nrealization of chemical analyses on magnetic tapes in collaboration with experts in the fields of materials science and chemistry,\r\nand (iv) the development of original open-source software tools. On the cultural side, the recovery, the safeguard, and the access\r\nto unique copies of unpublished live recordings of artists the calibre of Domingo and Pavarotti are of great musicological and\r\neconomical value....
We present a user-based method that detects regions of interest within a video in order to provide video skims and video summaries.\r\nPrevious research in video retrieval has focused on content-based techniques, such as pattern recognition algorithms that attempt\r\nto understand the low-level features of a video.We are proposing a pulse modeling method, which makes sense of a web video by\r\nanalyzing users� Replay interactions with the video player. In particular, we have modeled the user information seeking behavior\r\nas a time series and the semantic regions as a discrete pulse of fixed width. Then, we have calculated the correlation coefficient\r\nbetween the dynamically detected pulses at the local maximums of the user activity signal and the pulse of reference. We have\r\nfound that users� Replay activity significantly matches the important segments in information-rich and visually complex videos,\r\nsuch as lecture, how-to, and documentary.The proposed signal processing of user activity is complementary to previous work in\r\ncontent-based video retrieval and provides an additional user-based dimension for modeling the semantics of a social video on the\r\nweb....
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