Multiple layer data hiding scheme based on difference expansion of quad

For the past few years, the schemes of data hiding are growing rapidly. Generally, data hiding performs well on common images but it does not provide satisfying results on distortion sensitive images such as medical, military, or forensic images. This is because embedding data into an image can cause permanent distortion after extraction (irreversible). As a solution, a certain scheme is required for the process of embedding data into an image, such as reversible data hiding (RDH). One well-known RDH scheme is difference expansion, a simple and easy to implement scheme. In this study, a new scheme, multiple-layer embedding based on difference expansion of quad, is proposed, focusing on increasing capacity and visual quality of data hiding by reducing difference value in pixel with improved reduced difference expansion (IRDE). The proposed scheme has been evaluated with 14 grayscale images, consisting of six common images and eight medical images. Results show that the proposed scheme has higher capacity and better visual quality compared to the original scheme and previously similar schemes.