A novel removable visible watermarking algorithm based luminance contrast sensitivity function

This paper proposes a reversible visible watermarking algorithm based on luminance contrast sensitivity function (CSF) to satisfy a new application scenario where the visible watermark servers as a tag or ownership identifier, but can be completely removed at the receiver end to resume the original image. For our removable visible watermarking algorithm, we compute composite coefficients using characteristics of the host and watermark image in the discrete wavelet transform (DWT) domain. The visible watermark is securely embedded based on a use-key-controlled embedding mechanism. With correct user keys, authorized user can completely removed the watermark and lossless recover the original image. In contrast, unauthorized operations either overly or insufficiently remove the watermark due to wrong estimation of embedding parameters, and thus, the resulting image has apparent defect.