Image Content Protection Based on Multi-Layer Decomposition

In the paper is presented one approach for documents' image content protection based on layered still image decomposition with Inverse Difference Pyramid and digital watermark insertion, which permits the creation of hierarchical access control systems for large image databases. Unlike the famous pyramid decompositions (Laplacian, Gaussian, etc.), the IDP starts from the pyramid top, which comprises smallest number of coefficients, and continues with the next decomposition layers (i.e., it represents the processed image with consecutive approximations of increasing quality). The new approach permits the insertion of multiple watermarks in the consecutive decomposition layers (resistant and fragile) and their extraction by authorized users only. The new format is suitable for various applications image content protection for documents archiving; historical heritage protection; telemedicine and healthcare; transfer of confidential information with restricted access and many others.