Search

The utilization of forward error correction (FEC) schemes for stereo video streaming is investigated. Stereo video is categorized in 3 layers and each layer is protected with different protection ratios for efficient streaming. Systematic Reed-Solomon (RS) and Luby Transform (LT) codes are utilized as the error protection schemes. Detailed simulations are performed in order to observe the optimum unequal error protection (UEP) strategies for the defined video layers. Moreover, as a result of these simulations the performance comparison of RS and LT codes for video streaming is provided.

This work presents a multiple description coding (MDC) scheme for compressed three dimensional (3D) meshes based on forward error correction (FEC). It allows flexible allocation of coding redundancy for reliable transmission over error-prone channels. The proposed scheme is based on progressive geometry compression, which is performed by using wavelet transform and modified SPIHT algorithm. The proposed algorithm is optimized for varying packet loss rates (PLR) and channel bandwidth. Modeling distortion-rate function considerably decreases computational complexity of bit allocation.

This paper presents an efficient joint source-channel coding scheme based on forward error correction (FEC) for three dimensional (3D) models. The system employs a wavelet based zero-tree 3D mesh coder based on progressive geometry compression (PGC). Reed-Solomon (RS) codes are applied to the embedded output bitstream to add resiliency to packet losses. Two-state Markovian channel model is employed to model packet losses. The proposed method applies approximately optimal and unequal FEC across packets. Therefore the scheme is scalable to varying network bandwidth and packet loss rates (PLR). In addition, distortion-rate (D-R) curve is modeled to decrease the computational complexity. Experimental results show that the proposed method achieves considerably better expected quality compared to previous packet-loss resilient schemes.

Date of Conference: 7-9 May 2007 Conference Name: 3DTV Conference, IEEE 2007 In this paper, error resilient stereoscopic video streaming problem is addressed. Two different Forward Error Correction (FEC) codes namely Systematic LT and RS codes are utilized to protect the stereoscopic video data against transmission errors. Initially, the stereoscopic video is categorized in 3 layers with different priorities. Then, a packetization scheme is used to increase the efficiency of error protection. A comparative analysis of RS and LT codes are provided via simulations to observe the optimum packetization and UEP strategies.

Date of Conference: 12-13 November 2007 Conference Name: Packet Video 2007 - 16th International Packet Video Workshop A near optimal streaming system for stereoscopic video is proposed. Initially, the stereoscopic video is separated into three layers and the approximate analytical model of the Rate-Distortion (RD) curve of each layer is calculated from sufficient number of rate and distortion samples. The analytical modeling includes the interdependency of the defined layers. Then, the analytical models are used to derive the optimal source encoding rates for a given channel bandwidth. The distortion in the quality of the stereoscopic video that is caused by losing a NAL unit from the defined layers is estimated to minimize the average distortion of a single NAL unit loss. The minimization is performed over protection rates allocated to each layer. Raptor codes are utilized as the error protection scheme due to their novelty and suitability in video transmission. The layers are protected unequally using Raptor codes according to the parity ratios allocated to the layers. Comparison of the defined scheme with two other protection allocation schemes is provided via simulations to observe the quality of stereoscopic video.

In this paper, we propose a novel hybrid topology and interest based clustering to organize the overlay network in order to reduce startup latency and service interruption probability. Our method uses a clustering technique to organize the peers according to their interests and locality information. The proposed technique is compared with the current unstructured P2P architectures in terms of average hit time, hit ratio for searched content, and the maximum rate of information (in bits per second) that can be transmitted over P2P network caused by protocol and overlay- level connectivity. The simulation results show that the proposed system outperforms the current unstructured P2P architectures.

We propose a blind watermarking method where the watermark is a hologram itself. In the proposed approach, the quantized phase of the hologram is embedded into the wavelet-transformed host image using quantization index modulation. In the detection stage, wavelet transform of the watermarked image followed by a minimum distance decoder is used. The proposed method is blind since it requires only information about the quantizers and the parameters of the hologram recording process. The robustness of the proposed technique is tested against several attacks such as filtering, compression, occlusion, and cropping. Moreover, we discuss the effect of quantization of the hologram on the reconstruction quality.

In this paper, we address the problem of 3D model transmission over error-prone channels using multiple description coding (MDC). The objective of MDC is to encode a source into multiple bitstreams, called descriptions, supporting multiple quality levels of decoding. Compared to layered coding techniques, each description can be decoded independently to approximate the model. In the proposed approach, the mesh geometry is compressed using multiresolution geometry compression. Then multiple descriptions are obtained by applying multiple description scalar quantization (MDSQ) to the obtained wavelet coefficients. Experimental results show that, the proposed approach achieves competitive compression performance compared with existing multiple description methods.

H.264 is the current state-of-the-art monoscopic video codec providing almost twice the coding efficiency with the same quality comparing the previous codecs. With the increasing interest in 3D TV, multi-view video sequences that are provided by multiple cameras capturing the three dimensional objects and/or scene are more widely used. Compressing multi-view sequences independently with H.264 (simulcast) is not efficient since the redundancy between the closer cameras is not exploited. In order to reduce these redundancies, we propose a multi-view video codec based on H.264 using disparity estimation/compensation as well as motion estimation/compensation. In order to effectively search for disparity/motion without increasing computational complexity, we modified the buffering structure of H.264 and implemented several referencing modes. Our results show that for closely located cameras, our codec outperforms simulcast H.264 coding. For sparsely located cameras, our method can still improve coding gain depending on the video characteristics.

In this paper, we propose a blind watermarking method where watermark is chosen as the hologram of the signal to be embedded. In the proposed approach the quantized phase of the hologram is embedded into an image using quantization index modulation (QIM). The robustness of the proposed technique is tested against several attacks such as filtering, compression, occlusion and cropping. Also the effects of quantization of the hologram on the reconstruction quality are demonstrated.

A web-based system consisting of data entrance, access and retrieval modules is constructed for museums. Internet users that visit the e-museum, ■ are able to view the written and visual information belonging to the artworks in the museum, ■ are able to follow the virtual tour prepared for the different sections of the museum, ■ are able to browse the artworks according to certain properties, ■ are able to search the artworks having the similar visual content with the viewed artwork.

Today, stereoscopic and multi-view video are among the popular research areas in the multimedia world. In this study, we have designed and built a platform consisting of stereo-view capturing, real-time transmission and display. At the display stage, end users view video in 3D by using polarized glasses. Multi-view video is compressed in an efficient way by using multi-view video coding techniques and streamed using standard real-time transport protocols. The entire system is built by modifying available open source systems whenever possible. Receiver can view the content of the video built from multiple channels as mono or stereo depending on its display and bandwidth capabilities.

This paper presents and compares two multiple description schemes for coding of stereoscopic video, which are based on H.264. The SS-MDC scheme exploits spatial scaling of one view. In case of one channel failure, SS-MDC can reconstruct the stereoscopic video with one view low-pass filtered. SS-MDC can achieve low redundancy (less than 10%) for video sequences with lower inter-view correlation. MS-MDC method is based on multi-state coding and is beneficial for video sequences with higher inter-view correlation. The encoder can switch between these two methods depending on the characteristics of video.

Cataloged from PDF version of article. Transmission control protocol (TCP) with its well-established congestion control mechanism is the prevailing transport layer protocol for non-real time data in current Internet Protocol (IP) networks. It would be desirable to transmit any type of multimedia data using TCP in order to take advantage of the extensive operational experience behind TCP in the Internet. However, some features of TCP including retransmissions and variations in throughput and delay, although not catastrophic for non-real time data, may result in inefficiencies for video streaming applications. In this paper, we propose an architecture which consists of an input buffer at the server side, coupled with the congestion control mechanism of TCP at the transport layer, for efficiently streaming stored video in the best-effort Internet. The proposed buffer management scheme selectively discards low priority frames from its head-end, which otherwise would jeopardize the successful playout of high priority frames. Moreover, the proposed discarding policy is adaptive to changes in the bandwidth available to the video stream. 2004 Elsevier B.V. All rights reserved.

In order to compress stereo image pairs effectively, disparity compensation is the most widely used method. In this paper we examined the effects of using different disparity maps and their properties in an embedded JPEG2000 based disparity compensated stereo image coder. These properties include the block size, estimation method and the resulting entropy of the disparity map. Experimental results show that basic block matching gives better results than ground truth, especially on occluded regions and boundaries.

This document describes a universal multimedia access system and its implementation details. In the context of this document, universal multimedia access means accessing multimedia content over ubiquitous computer networks, using different computing platforms. The computer networks involve both wired and wireless networks, and computing platforms involve wired PC, mobile PC and personal digital assistants (PDA). The system is built on a client/server architecture. Video data is H.263 coded and carried over RTP. The Java Media Framework is utilized and its capabilities are extended with special plug-ins when necessary.

In this paper, a new face recognition system, GAYE, is presented. GAYE is a fully automatic system that detects and recognizes faces in cluttered scenes. The input of the system is any digitized image/image sequence that includes face/faces. The basic building blocks of the system are face detection, feature extraction and feature comparison. Face detection is based on skin color segmentation. For feature extraction, a novel approach is proposed that depends on the Gabor wavelet transform of the face image. By comparing facial feature vectors system finally makes a decision if the incoming person is recognized or not. Real time system tests show that GAYE achieves a recognition ratio over %90.

In the year 2000 a competition was organised to collect face verification results on an identical, publicly available data set using a standard evaluation protocol. The database used was the Xm2vts database along with the Lausanne protocol [14]. Four different institutions submitted results on the database which were subsequently published in [13]. Three years later, a second contest using the same dataset and protocol was organised as part of AVBPA 2003. This time round seven seperate institutions submitted results to the competition. This paper presents the results of the competition and shows that verification results on this protocol have increased in performance by a factor of 3. © Springer-Verlag 2003.

Date of Conference: 28 January- 1 February 2007 Conference Name: IS&T/SPIE Electronic Imaging, 2007 In this paper, we propose a new low-complexity retransmission based optimal video streaming and rate adaptation algorithm. The proposed OSRC (Optimal packet Scheduling and Rate Control) algorithm provides average reward optimal solution to the joint scheduling and rate control problem. The efficacy of the OSRC algorithm is demonstrated against optimal FEC based schemes and results are verified over TFRC (TCP Friendly Rate Control) transport with ns-2 simulations.

We suggest a compound full-reference stereo-video quality metric composed of two components: a monoscopic quality component and stereoscopic quality component. While the former assesses the trivial monoscopic perceived distortions caused by blur, noise, contrast change etc., the latter assesses the perceived degradation of binocular depth cues only. We use the structural similarity index as a measure for perceptual similarity and design a multiscale algorithm for obtaining a perceptual disparity map and a stereo-similarity map to be used in the suggested metric. We verify the performance of the metric with subjective tests on distorted stereo images and coded stereo-video sequences with a final aim to build a perceptually-aware feedback for a H.264 based stereo-video encoder

In this work, we present a multiple description coding (MDC) scheme for reliable transmission of compressed three dimensional (3-D) meshes. It trades off reconstruction quality for error resilience to provide the best expected reconstruction of 3-D mesh at the decoder side. The proposed scheme is based on multiresolution geometry compression achieved by using wavelet transform and modified SPIHT algorithm. The trees of wavelet coefficients are divided into sets. Each description contains the coarsest level mesh and a number of tree sets coded with different rates. The original 3-D geometry can be reconstructed with acceptable quality from any received description. More descriptions provide better reconstruction quality. The proposed algorithm provides flexible number of descriptions and is optimized for varying packet loss rates (PLR) and channel bandwidth.