EURASIP Journal on Applied Signal Processing 
Volume 2002 (2002), Issue 2, Pages 197-208
doi:10.1155/S1110865702000549

Robust Watermarking of Cartographic Images

Mauro Barni,1 Franco Bartolini,2 Alessandro Piva,2 and Filippo Salucco2

 1Department of Information Engineering, University of Siena, Via Roma 56, Siena 53100, Italy
2Department of Electronics and Telecommunications, University of Florence, Via S. Marta 3, Firenze, 50139, Italy
Received 30 April 2001; Revised 15 October 2001

Abstract

We present a method (Text-Based Geometric Normalization—TBGN) which, by exploiting the particular content of cartographic images, namely text content, permits to cope with global geometric transformations. First, text is extracted from the to-be-marked map, then text orientation and size are exploited to normalize the image geometry prior to watermark insertion. Watermarking is performed by means of any of the existing algorithms ensuring good robustness against image processing tools. At the decoder side, text is extracted again from the map and used to normalize image geometry. Owing to the robustness of text features with respect to common image manipulations, and to the likely spreading of text all across the digital map, the proposed system exhibits an excellent robustness.