Watermarking of dither halftoned images

watermarking, halftone printing, printing security, dithering This report concerns embedding of watermarks into dither halftoning. The basic idea is to use a sequence of two dither matrices (instead of one) to encode the watermark. Assuming a specific distribution of the input image leads to an optimal decoding algorithm, and an optimal dither matrix pair matching. Finally, an example is given, which demonstrates the ideas. The example is synthetic in the sense that it does not use printing and re-scanning of the image.