Analysis of the bounds for linear block codes in watermark channel

Abstract

Robustness is one of the fundamental requirements of digital watermarking in many applications. To improve watermark robustness, some researchers proposed to employ error correcting coding (ECC). However, due to the constraint of imperceptibility, the redundancy introduced by ECC will decrease embedding strength of the watermark. That is, coding ratio of ECC greatly affects the amplitude of watermark signal. It is this point that makes watermark channel different from conventional communication channel. Thus, a question arises. How to choose the coding ratio so that ECC could bring coding gain in the watermark channel? This paper analytically and experimentally investigates the problem. By using Plotkin Bound and Hamming Bound, we present the coding ratio constraints of binary and non-binary linear block codes. Our conclusions can easily extend to convolutional codes. © Springer-Verlag 2004.