Distributed Coding of Highly Correlated Image Sequences with Motion-Compensated Temporal Wavelets
- PDF / 530,768 Bytes
- 10 Pages / 600.032 x 792 pts Page_size
- 22 Downloads / 176 Views
Distributed Coding of Highly Correlated Image Sequences with Motion-Compensated Temporal Wavelets Markus Flierl1 and Pierre Vandergheynst2 1 Max
Planck Center for Visual Computing and Communication, Stanford University, Stanford, CA 94305, USA Processing Institute, Swiss Federal Institute of Technology Lausanne, 1015 Lausanne, Switzerland
2 Signal
Received 21 March 2005; Revised 27 September 2005; Accepted 4 October 2005 This paper discusses robust coding of visual content for a distributed multimedia system. The system encodes independently two correlated video signals and reconstructs them jointly at a central decoder. The video signals are captured from a dynamic scene, where each signal is robustly coded by a motion-compensated Haar wavelet. The efficiency of the decoder is improved by a disparity analysis of the first image pair of the sequences, followed by disparity compensation of the remaining images of one sequence. We investigate how this scene analysis at the decoder can improve the coding efficiency. At the decoder, one video signal is used as side information to decode efficiently the second video signal. Additional bitrate savings can be obtained with disparity compensation at the decoder. Further, we address the theoretical problem of distributed coding of video signals in the presence of correlated video side information. We utilize a motion-compensated spatiotemporal transform to decorrelate each video signal. For certain assumptions, the optimal motion-compensated spatiotemporal transform for video coding with video side information at high rates is derived. It is shown that the motion-compensated Haar wavelet belongs to this class of transforms. Given the correlation of the video side information, the theoretical bitrate reduction for the distributed coding scheme is investigated. Interestingly, the efficiency of multiview side information is dependent on the level of temporal decorrelation: for a given correlation SNR of the side information, bitrate savings due to side information are decreasing with improved temporal decorrelation. Copyright © 2006 Hindawi Publishing Corporation. All rights reserved.
1.
INTRODUCTION
Robust coding of visual content is not just a necessity for multimedia systems with heterogeneous networks and diverse user capabilities. It is also the key for video systems that utilize distributed compression. Let us consider the problem of distributed coding of multiview image sequences. In such a scenario, a dynamic scene is captured by several spatially distributed video cameras and reconstructed at a single central decoder. Ideally, each encoder associated with a camera operates independently and transmits robustly its content to the central decoder. But as each encoder has a priori no specific information about its potential contribution to the reconstruction of the dynamic scene at the central decoder, a highly flexible representation of the visual content is required. In this work, we use a motion-compensated lifted wavelet transform to generate highly scalable bitstreams th
Data Loading...
