Recovering Watermarks from Images

Zoran Duric, Neil F. Johnson, and Sushil Jajodia. Recovering Watermarks from Images, Information & Software Engineering Technical Report ISE-TR-99-04, April 1999.
[PDF File (1.8MB)]

Abstract

Many techniques for watermarking of digital images have appeared recently. 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 recognizing images based on the concept of identification marks; 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 recognize distorted images and recover their original appearances. Once the image is recognized we use a second technique based on normal flow to fine-tune image parameters. The restored image can be used to recover watermarks that were embedded in the images by their owner.