A hybrid scheme for enhancing recovered image quality in polynomial based secret image sharing by modify-and-recalculate strategy

A hybrid approach for enhancing the recovered image quality in Shamir’s polynomial based secret image sharing (SIS) is proposed in this paper. To remain computational efficiency, simple modular arithmetic is still used. The fundamental operation in the proposed method is mod P calculation, where P is a prime. A framework for the proposed method is firstly given. Mod PG and mod PS sharing algorithms are included. Then, a modify-and-recalculate strategy for mod PS sharing is proposed to make sure that each generated modular result is within the interval [0,2N−1]. Theoretical analysis on recovered image quality and extensive experiments are conducted. Recommendation on choosing optimal sharing method for different values of N (8 ≤ N ≤ 17) is given.