ABSTRACT
This chapter focuses on the problems of detecting the visible watermarks from images and removing the watermarks to generate the watermark-free images. It presents the Fourier-based image alignment method with iterative refinement for the watermark detection. The chapter describes how to remove the watermark from the image after the watermark is precisely detected. It discusses how to improve the image alignment accuracy under occlusion or outliers by introducing the distance weighting scheme in the proposed algorithm. Some experimental results are given to show the performance of the proposed watermark detection and removal algorithm on real watermark documents and images. Visible image watermark is commonly used to protect the copyright of documents and images. However, visible image watermark may cause problems for automatic understanding or analysis of the document or image contents, which is required for information or image retrieval. Experimental results demonstrate satisfactory watermark removal results for both the picture and document images.
