3 - An improved method for high hiding capacity based on LSB and PVD

Abstract

In this chapter, we propose an improved image steganography method using the concept of least significant bit (LSB) substitution and pixel value differencing (PVD). The major contributions of the proposed method are (i) increase of the hiding capacity (HC), (ii) avoiding fall off boundary problem (FOBP), and (iii) resistance to regular and singular (RS) and pixel difference histogram (PDH) attack. Initially, the cover image is partitioned into blocks of three consecutive pixels. A reference pixel is chosen from each block, and then the pixels are readjusted. Further, the difference values are found using the smallest pixel of the block. Finally, the stego-pixels are obtained using the difference value and the smallest pixel. Additionally, to avoid FOBP, the pixel shifting process has been carried out for the pixels that fall out of the boundary. The observed result outperforms other existing state-of-the-art methods in terms of the steganographic parameters like peak signal-to-noise ratio (PSNR), HC, the number of fall off boundary pixels, and structural similarity index metric (SSIM).