Wavelet-based digital watermarking with halftoning technique

In this paper, we present a watermarking scheme using the halftone technique to embed gray scale logo images as watermark signals. To embed the watermark, the gray scale logo image first undergoes a halftoning process to become a 1-bit image before embedding. Direct spread spectrum is used to insert the watermark signal into the original image. The robustness and invisibility of the proposed scheme are determined by the chip-rate and another parameter. The method is proved to be robust to different signal processing techniques.