Adaptive pixel value differencing steganography using both vertical and horizontal edges

Abstract

This paper proposes two pixel value differencing (PVD) steganography techniques by considering adaptive ranges to improve the security. In the first technique, the image is partitioned into 2ź?ź2 pixel blocks in a non-overlapping fashion and scanned in raster-scan order. For every 2ź?ź2 pixel block the left-upper and bottom-right corner pixels are targetted based on their correlation with the other two pixels. Both horizontal and vertical edges are considered. In the second technique, the image is partitioned into blocks with 3ź?ź3 pixels in an overlapped fashion and scanned in raster-scan order. For a block the central pixel is targetted for embedding. Both the horizontal and vertical edges are inspected, but one of them is considered for data embedding at the target pixel. The ranges are adaptively calculated based upon the local statistics of the blocks. The first technique provides higher hiding capacity and the second technique provides higher peak signal-to-noise ratio value.