Twice Gric Colorings in Steganography

A novel method of steganographic embedding is described based on vertex colorings in the grid graph, in which rainbow coloring is repeated in every block of cover signals to increase embedding efficiency. This is an improvement of the previous grid coloring method in steganography. It also outperforms LSB matching revisited method and direct sums of ternary Hamming codes. The proposed method can generate more embedding schemes which cover the range of change rates and information rates more densely.