Screen-Based Watermarking Of Aperiodic, Clustered-Dot Halftones

Aperiodic, clustered-dot halftoning can overcome the inherent instability of electrophotographic (EP) printing technologies. In our previous work, we described a screen design algorithm based on Direct Binary Search (DBS) that yields aperiodic, clustered-dot halftone textures. In the present paper, we introduce a new microscreen design algorithm that allows the embedding of binary metadata in an aperiodic, clustered-dot halftone image with no loss of visual quality. We also describe a simple method for decoding the embedded metadata with only a knowledge of the two microscreens used to halftone the continuous-tone image. Our results with one image demonstrate 100% recovery of the embedded metadata.