Spatial-Based Watermarking Schemes and Pixel Selection.

Spatial domain based watermarking is one of the fundamental techniques at the beginning of digital watermarking. Generally speaking, spatial domain based watermarking schemes possess the advantages, such as easy implementation and low complexity, than other domain based watermarking schemes. But also, they posses the shortages like weak robustness and non-practical usage than other domain based watermarking schemes. In this chapter, we concentrate on spatial domain based watermarking techniques and the procedure that improves their performance. We begin with the introduction of this area in the first section, then follow by illustrating two spatial-based watermarking schemes in the second section. The first scheme is the last-significant-bit (LSB) modification method, which is a well-known classical scheme. The second one is a pixel surrounding method, which provides better robustness. Experimental results and comparison are also given in this section. In the third section, a training procedure called genetic pixel selection (GPS) is introduced. It takes the considered methods of attack into account, and employs genetic algorithms to find a better way to select a number of pixels from the cover image to carry the watermark signal. Comparisons of the simulation results with and without the GPS procedure are addressed in the fourth section. Finally, the last section summarises this chapter