Gray Value based Adaptive Data Hiding for Image Authentication (GVADHIA)

Abstract

This paper presents a novel adaptive data hiding method in gray images using complement value (CV) of higher order three bits (b7, b6 and b5) of each gray image byte to achieve large embedding capacity and imperceptible stegoimages. The technique exploits the complement value (CV) at each gray image byte to estimate how many bits will be embedded into the image byte. Image byte located in the edge areas are embedded by k-bit LSB substitution technique with a large value of k in deep blackish area than that of the image bytes located in the light gray areas. Any image byte is embedded by the k-bit LSB substitution technique. The value of k is adaptive and is decided by the complement value. In order to keep the fidelity of the embedded image at same level of source image, a re-adjusting phase is used called handle. The experimental results obtained compared with the existing studies of Wu et al’s LSB replacement method based on pixel-value differencing (PVD) in gray images, where the proposed GVADHIA is capable to hide large volume of data and gives better image quality than existing techniques. Real life applications of the proposed technique to authenticate legal document has also been discussed. Keywords: Steganography, Complement Value (CV), gray image, edges, PVD.