A multiresolution watermark for digital images

TLDR

The paper introduces a new multiresolution watermarking method for digital images. The method embeds pseudo‑random codes into the large DWT coefficients of the high and middle frequency bands, using a hierarchical scheme based on the discrete wavelet transform. The watermark is more robust than existing methods against wavelet‑based compression and halftoning, and its detection cost scales with the image noise level.

Abstract

We introduce a new multiresolution watermarking method for digital images. The method is based on the discrete wavelet transform (DWT). Pseudo-random codes are added to the large coefficients at the high and middle frequency bands of the DWT of an image. It is shown that this method is more robust to often proposed methods to some common image distortions, such as the wavelet transform based image compression, and image halftoning. Moreover, the method is hierarchical. The computation load needed to detect the watermark depends on the noise level in an image.