Extended Directional IPVO for Reversible Data Hiding Scheme

Abstract

Pixel Value Ordering (PVO) is a data hiding technique through which pixels within an image block are ranked and modify minimum or maximum pixel value for data embedding. In this paper, we proposed an Extended Directional Improved PVO (EDIPVO) for Reversible Data Hiding (RDH) scheme. The original image pixel blocks are interpolated by inserting extra pixels between each row and each column. During data embedding, we consider a parameter $(\alpha )$, perform addition with maximum pixel value, and subtract $\alpha$ from minimum pixel value to maintain the order within the pixel block. The parameter $\alpha$ is dependent on the size of the original image block. To increase data hiding capacity, we have considered pixel ranking in three different directions: (1) horizontal, (2) vertical, and (3) diagonal within each block. The secret data bits are embedded starting from the largest, second largest, and so on for maximum value modification and smallest, second smallest, and so on for minimum value modification. The data embedding capacity has been improved than previous data hiding schemes while keeping visual quality unaltered. Experimental results are compared with existing state-of-the-art methods and achieve good results.