Scalable user-friendly image sharing

Image sharing addresses a fault-tolerant protection mechanism for important images. In a typical image sharing scheme, the generated shadow images usually have a noise-like appearance that conceals the secret image completely, but this makes them difficult to identify and manage. This paper proposes a scalable user-friendly image sharing scheme in which each generated shadow image looks like a shrunken replica of the original image. The scheme provides an easy-to-identify interface for managing the shadow images. Compared with previous user-friendly image sharing schemes, the proposed method can reconstruct the original image without any loss and still has the small-size shadow images. A notable feature is that the qualities of generated shadow images are scalable in the proposed scheme, which allows the quality of the shadow images to be adjusted according to the requirements of diverse applications.