Recovery of watermarks from distorted images

Abstract

Many techniques for watermarking of digital images have appeared in numerous publications. Most of these techniques are sensitive to cropping and/or affine distortions (e.g., rotation and scaling). In this paper we describe a method for the recovery of original size and appearance of images based on the concept of identification marks (“fingerprints”); the method does not require the use of the “original” image, but only a small number of salient image points. We show that, using our method, it is possible to recover original appearances of distorted images. The restored image can be used to recover embedded watermarks.