Abstract

A method of concealing an image in a different halftone image is proposed. Continuous-tone levels of the visible images are represented by the area of the halftone dots. However, the hidden image is encoded by the dots’ positions inside their cells. Only a spatial correlator with a unique filter function can reveal the hidden image from the halftone picture. The technique and its robustness to noise and distortions are demonstrated.

© 2001 Optical Society of America

Moiré patterns in scanned halftone pictures

Arden Steinbach and Kwan Y. Wong
J. Opt. Soc. Am. 72(9) 1190-1198 (1982)

Watermarks encrypted in a concealogram and deciphered by a modified joint-transform correlator

David Abookasis, Ofir Montal, Ohad Abramson, and Joseph Rosen
Appl. Opt. 44(15) 3019-3023 (2005)

Objective quality measures for halftoned images

Fredrik Nilsson
J. Opt. Soc. Am. A 16(9) 2151-2162 (1999)

Acousto-optic imaging of a color picture hidden behind a scattering layer

Terence S. Leung and Shihong Jiang
Opt. Express 21(22) 26780-26785 (2013)

Halftone images: Spatial resolution and tone reproduction*

Olof Bryngdahl
J. Opt. Soc. Am. 68(3) 416-422 (1978)