Presenter

Mr Andrei Sechelea - ETRO, Vrije Universiteit Brussel [Email]

Abstract

Slepian-Wolf (SW) coding, which is concerned with separate lossless compression of correlated
sources with joint decoding, forms the basis of distributed source coding (DSC) and can be used
to exploit the correlation among quantized sources in lossy DSC problems such as Wyner-Ziv (WZ)
coding and multiterminal (MT) source coding. SW theory states that the coding performances of
a system performing independent encoding and joint decoding of two correlated sources are the
same with the case when the two sources are jointly encoded and decoded. A practical
development of the above information theoretical facts is the distributed video coding (DVC)
framework which allows to move the computation complexity from the encoder which is usually
facing computational constraints to the decoder. This recent field of research has shown
increased interesting for a wide range of applications, such as video surveillance, real-time
streaming from multiple cameras, and immersive communications in general.
The thesis proposes an in-depth theoretical analysis of the problem of lossy compression of
binary sources in the presence of correlated side information, where the correlation is given by
a generic binary asymmetric channel and the Hamming distance is the distortion metric. We
derive for the first time the rate-distortion function for conventional predictive coding in the
binary-asymmetric-correlation channel scenario. Moreover, we propose a new numerical bound
for the case where the side information is only available at the decoder - Wyner-Ziv coding. We
conjecture this bound to be the actual rate-distortion function. We complement our analysis with
an analytical approximation of the solution which has a negligible estimation error when
compared to the actual rate-distortion function. Furthermore, we show that the maximum rate
needed to encode as well as the maximum rate loss of Wyner-Ziv coding relative to predictive
coding correspond to uniform sources and symmetric correlations. Importantly, we show that
the upper bound on the rate-loss established in literature is not tight and the maximum loss is
actually significantly lower. Finally, we prove that the only binary correlation channel that incurs
no rate-loss for Wyner-Ziv coding compared to predictive coding is the Z-channel.

Short CV

Master in Engineering sciences, EPFL, 2010