Distributed image coding for imformation recovery from the print-scan channel
A printed photograph is difficult to reuse because the digital pixels that generated it are no longer available. This paper describes approximating the original digital pixels by combining a scan of the printed photograph with small amounts of digital auxiliary information kept with the print, using an encoding such as a dense barcode. The auxiliary information enables accurate registration and color-reproduction, and the recovery of information lost due to the print-scan channel, by distributed source coding techniques. Approximating the original digital image enables many uses, including making high-fidelity reprints, as well as robust watermark detection. A block entropy coder using terminated tree codes for cosets of DCT coefficients is proposed for distributed image coding.