A novel data hiding scheme for keeping high stego-image quality

The LSB-based data hiding scheme is to embed the secret data into the least significant bits of the pixel values in a cover image. When the size of the embedded secret data is bigger, this processing will degrade the quality of the stego-image so significantly as to catch the attention of hostile interceptors. To overcome this drawback, in this paper, we propose a high-capacity, high-quality data hiding scheme. First, the proposed scheme divides the pixel value range into several non-overlapping regions. For each spatial pixel value in the cover image, we embed one secret-bit into it by using the difference expansion technique in single pass, where the difference is calculated between the spatial pixel and the start or end of the region it is situated in. Owing to the use of the difference expansion technique, this processing is also suitable for multiple-layer embedding. Experimental results show significant improvement with respect to the embedding capacity. In addition, the distortion in the stego-image is almost invariable regardless of the increase of the load of embedded data