A Recoverable Visible Digital Image Watermarking Based on the Dyadic Lifting Scheme

We propose a new recoverable visible digital image watermarking method based on the dyadic lifting scheme. This method generates a visible watermarked image by embedding a binary logo into an image using the dyadic wavelet transform (DYWT) and interval arithmetic (IA).The dyadic lifting scheme contains free parameters that enable us to construct filters having features of the original image. Our method can uniquely identify such free parameters by solving linear equations derived from the original image and the watermarked image. Using these parameters, we can produce new filters to remove an embedded watermark from the watermarked image and recover the original image. These new filters play the role of a recovery key for recovering the original image. The visible watermarked image can deter image piracy at the same time, because the copyright infringer cannot remove the visible water mark and take the liberty of using the original copyrighted image without the recovery key. Therefore, only the person who is authorized to have the recovery key can use the original image. Experimental results demonstrate that our method gives watermarked images that have better quality and that are robust with respect to attacks such as marking, clipping, contrast tuning, median filtering, addition of Gaussian white noise, addition of salt & pepper noise, JPEG and JPEG 2000 compression, rotation, and resizing, and can recover approximately the original image without problems in practical use.