Edge Analysis Based Data Hiding on Digital Images with PVD Technique

Abstract

This paper proposes a new improved steganographic technique based on pixel value differencing [14] which is driven by edge recognition technique. The cover image is divided into blocks and rotated first to generate edges [10] in the image and is used as the candidate region to perform data hiding using pixel value differencing. The basic idea of pixel value differencing is a cover image is partitioned into non-overlapping blocks of two consecutive pixels. A difference value is calculated from the values of the two pixels in each block. All possible difference values are classified into a number of ranges. The difference value then is replaced by a new value to embed the value of a sub-stream of the secret message. The number of bits which can be embedded in a pixel pair is decided by the width of the range that the difference value belongs to. The method is designed in such a way that the modification is never out of the range interval. This method provides an easy way to produce a more imperceptible result than those yielded by simple least-significant-bit replacement methods. The embedded secret message can be extracted from the resulting stego-image without referencing the original cover image. Moreover, a pseudorandom mechanism may be used to achieve secrecy protection.