Abstract: A reversible data hiding algorithm based on interpolation technique and reference matrix is proposed in this paper. Firstly, the cover image is interpolated to generate an interpolated image using an improved linear interpolation method. Then, the interpolated image is divided into non-overlapped blocks with size 2×2. And the pixel in top-left corner of each block is taken as horizontal ordinate of the point in plane. Moreover, other pixels are taken as vertical ordinates to construct three coordinate points, which are mapped into reference matrix. Finally, the vertical ordinates are modified in accordance with the decimal value of secret data and the value of corresponding coordinate points in reference matrix to realize data hiding. During data extraction, three coordinate points of each block are constructed via the same method in data hiding and mapped into the reference matrix to obtain the values of corresponding coordinate points to achieve data extraction. Since only interpolated pixels are modified and the original pixels keep unchanged, the cover image can be recovered without loss. Experimental results demonstrate that the proposed algorithm reaches high embedding capacity and has good visual quality.

Key words: image interpolation, linear interpolation, reversible information hiding, reference matrix