  A dual watermarking scheme based on Sobolev type orthogonal moments, Charlier
and Meixner, is proposed based on different discrete measures. The existing
relation through the connection formulas allows to provide with structure and
recurrence relations, together with two difference equations satisfied by such
families. Weighted polynomials derived from them are being applied in an
embedding and extraction watermarking algorithm, comparing the results obtained
in imperceptibly and robustness tests with other families of polynomials.
