PI-preserve data hiding for halftone image

In this paper, we propose a new data hiding algorithm for halftone images, namely pattern-and-intensity-preserve data hiding (Pi-preserve) which hides data without the help of original grayscale image. In this system, we introduce the pattern-preserve method to hide data and image dependent code error sensitive (IDC_ES) to enhance the security and sensibility to error. It achieves a considerably high visual quality, and has a better performance in terms of modified peak-signal-to-noise ratio (MPSNR) when compared with data hiding self toggling (DHST) and data hiding smart pair toggling (DHSPT) [Ming Sun Fu, April 2002]. The complexity is relatively low as no connectivity measurement is needed in the embedding process. Pi-preserve is suitable for data authentication.