Visual communications with side information via distributed printing channels: extended multimedia and security perspectives

In this paper we address visual communications via printing channels from an information-theoretic point of view as communications with side information. The solution to this problem addresses important aspects of multimedia data processing, security and management, since printed documents are still the most common form of visual information representation. Two practical approaches to side information communications for printed documents are analyzed in the paper. The flrst approach represents a layered joint source-channel coding for printed documents. This approach is based on a self-embedding concept where information is flrst encoded assuming a Wyner-Ziv set-up and then embedded into the original data using a Gel'fand-Pinsker construction and taking into account properties of printing channels. The second approach is based on Wyner-Ziv and Berger-Flynn-Gray set-ups and assumes two separated communications channels where an appropriate distributed coding should be elaborated. The flrst printing channel is considered to be a direct visual channel for images (\analog" channel with degradations). The second \digital channel" with constrained capacity is considered to be an appropriate auxiliary channel. We demonstrate both theoretically and practically how one can beneflt from this sort of \distributed paper communications".