Distributed Video Coding for wireless lightweight multimedia multimedia applications

In the modern wireless age, lightweight multimedia technology stimulates attractive commercial applications on a grand scale as well as highly specialized niche markets. In this regard, the design of efficient video compression systems meeting such key requirements as very low encoding complexity, transmission error robustness and scalability, is a challenging problem. The solution can be found in fundamental information theoretic results giving rise to distributed, or alias Wyner-Ziv, video coding. This dissertation first focuses on designing effective side information generation techniques so as to boost the compression capabilities of Wyner- Ziv video codecs. To this end, overlapped block motion estimation and compensation, a novel technique that performs multi-hypothesis prediction at the decoder, is proposed. Using auxiliary (i.e., hash) information sent to the decoder, the proposed technique triggers the design of efficient Wyner- Ziv video codecs. Furthermore, when coupled with an alternative side information creation method, the designed technique enables side information refinement after decoding critical information. The second part of this dissertation introduces a novel correlation channel modeling concept, which expresses the correlation noise as being statistically dependent on the side information. Compared to sideinformation- independent noise modeling adopted in traditional Wyner-Ziv coding solutions, it is theoretically proven that side-information-dependent modeling improves the coding performance. Anchored in this finding, a novel algorithm for online successively refined side-information-dependent channel estimation is introduced. The proposed algorithm brings significant coding gains over several state-of-the-art methods. The third contribution of this dissertation is the expansion of the application domain of Wyner-Ziv coding from conventional video to medical imaging. Wireless capsule endoscopy in particular, which is essentially wireless video capturing and transmission by a pill, is proven to be a promising application field. Driven by such applications, a novel hashbased Wyner-Ziv video coding system is proposed. The developed codec is able to cope even with extreme spatial variations in temporal correlation, often appearing in endoscopic video content. By supporting low complexity and scalability, and by delivering improved Wyner-Ziv performance compared to the state-of-the-art, the developed codec constitutes a strong candidate for lightweight (medical) imaging applications.