Two level data encoding approach for reversible data hiding in dual Stego images

Abstract

Due to high embedding capacity and security, dual stego-image based data hiding has become so popular. This paper proposes a two-level data encoding approach for reversible data hiding in dual stego-images. In the first level of encoding, the encoded intensities are estimated from the message intensities by assigning lower intensities to higher histogram data and higher intensities to lower histogram data. In the second level of encoding, the encoded intensities are folded by identifying the negative values to obtain the folded intensities. The folded intensities are embedded in the cover image to obtain the dual stego-images. The two-level data encoding process reduces the intensity of secret data which increases the quality of the two stego-images. During the extraction process, the folded intensities are extracted from the dual stego images. The folded intensities are decoded to encoded intensities and then to message intensities to obtain the secret data. This two-level data encoding approach increases the peak signal to noise ratio (PSNR) around 2 dB, and embedding rate (bpp) by 1%when compared to the traditional data hiding approach in dual stego images.