Iterative decoding of scale invariant image data-hiding

The vulnerability of quantization-based data hiding methods to amplitude scaling requires the formulation of countermeasures to this relatively simple attack. Rational dither modulation (RDM) was recently proposed as a quantization-based data hiding scheme, which is scaling invariant. This is achieved by a simple modification of the well-known dither modulation (DM) data hiding method. The performance of RDM, asymptotically in the memory size of the system, can be made to approach that of DM on the Gaussian channel. In this work we examine the application of near-optimal channel coding to RDM. The channel model required to undertake iterative decoding is presented and the proposed method is applied to real image data.