An Enhanced Image Steganographic Method with High Payload Capacity using Multidirectional Block Based Pixel-Value Differencing

To increase the payload capacity of the hidden secret information and to provide an imperceptible stegoimage for human vision, an enhanced steganographic method using multidirectional block based pixel-value differencing is proposed in this paper.To enhance the hiding payload capacity in image an steganographic method based on three-pixel block differences by Lin and Hseuh referring to only one direction but in the proposed method multi directional edges are considered and effectively adopted to design the scheme of multi directional block based PVD.As we know our human vision is sensitive to slight changes in the smooth regions, while it can tolerate more severe changes in the edge regions, in proposed method more secret data is embedded in those busy regions.In addition, to reduce the quality distortion of stego-image brought from setting larger embedding capacity, an optimal approach of selecting the reference point and adaptive rules are presented. This approach can be apply to gray as well as colored image also.Experimental results show that the proposed scheme can provide higher embedding capacity and give protection from dual statistical stego-analysis.Besides, the embedded confidential data can be extracted from stegoimages without the need of original images.