Reversible Data Embedding Using Reduced Difference Expansion

Abstract

The general difference expansion method uses reversible integer transform to embed information into a digital image and perfectly restores the original image after removing the hidden data. In multilayer embedding applications, the operation of difference expansion may seriously degrade the visual quality of the embedded image. In this paper, we propose a reduced difference expansion method to solve this problem. Theoretically, in the worst case, the proposed method gains 6-dB improvement in visual quality of the embedded image compared with the general difference expansion method. Therefore, the proposed method is suitable for multilayer data embedding.

Protecting Data by Improving Quality of Stego Image based on Enhanced Reduced difference Expansion

“…In another research done to improve the visual quality of stego image, Liu et al [16] proposed to reduce the difference before the embedding process. The reduction is performed if and only if the difference is greater than 2 , otherwise it is not reduced, see Equation 14where is the reduced difference.…”

“…At the receiver side, the secret message bits are extracted from the embedded differences by using the function. Next, the original difference is recovered by using Equation (16). Once the value has been obtained, the original pixel is recovered using the same expression in [8].…”

“…Once the value has been obtained, the original pixel is recovered using the same expression in [8]. (16) In [17], an improved quad and Reduced Difference Expansion (RDE) data hiding algorithm was presented. In this method, the quality of stego image has increased due to further reduction of difference between adjacent pixels.…”

“…In order to reduce image distortion after embedding process, difference reduction formula proposed in [16] is improved to get smaller differences, as depicted in Equation 18where varies from 0 to 3. That is, the reduction is performed for both negative and positive difference values except the difference that is equal to 0 or 1 which may cause either overflow or underflow.…”

Share a Secret Image With Invertible and Lossy Charateristics

“…Because an invertible secret image sharing scheme requires embedding abilities, the reversible watermarking method efficiently solves this problem; thus the proposed scheme used a reversible watermarking scheme to create an efficient invertible secret image sharing scheme. Difference expansion methods 14,15 can reversibly embed watermarks into cover images. Hu et al 16 improved embedding performance using M-ary number systems.…”