Regular Articles

Detecting spatially varying gray component replacement with application in watermarking printed images

[+] Author Affiliations
Ricardo L. de Queiroz

Universidade de Brasília Departamento de Engenharia Elétrica CP 4386, Brasília DF 70919-970 Brazil

Karen M. Braun

Xerox Corporation 800 Phillips Rd. M/S 128-27E Webster, New York 14580

Robert P. Loce

Xerox Corporation 800 Phillips Rd. M/S 128-27E Webster, New York 14580

J. Electron. Imaging. 14(3), 033016 (August 01, 2005). doi:10.1117/1.2001671
History: Received April 06, 2004; Revised August 31, 2004; Accepted March 15, 2005; Published August 01, 2005; Online August 01, 2005
Text Size: A A A

We present a method to include watermarks in printed images. With accurate printer calibration, in theory, the same color under different gray component replacement (GCR) strategies should look the same, under specific viewing conditions. We spatially vary the GCR along the image in a manner that is not perceptible, and we employ an estimation method to detect such changes. The choice of GCR for a given pixel (or region) comprises an additional information channel that embeds a watermark or hidden information. The challenge is how to detect which GCR was used and that is our focus. For that, we estimate the RGB value of each pixel and the CMYK values intended to be put onto the paper by scanning the printed page. With that information, we can estimate which GCR strategy was used in a given region and retrieve the watermark message. Instead of focusing on a particular watermarking scheme, we are concerned only with the practical aspects of producing a spatially varying GCR and of robustly estimating which GCR strategy was used at a region. Promising GCR detection results are shown to illustrate the method’s potential to watermark printed images.

Figures in this Article
© 2005 SPIE and IS&T

Citation

Ricardo L. de Queiroz ; Karen M. Braun and Robert P. Loce
"Detecting spatially varying gray component replacement with application in watermarking printed images", J. Electron. Imaging. 14(3), 033016 (August 01, 2005). ; http://dx.doi.org/10.1117/1.2001671


Access This Article
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Related Book Chapters

Topic Collections

Advertisement
  • Don't have an account?
  • Subscribe to the SPIE Digital Library
  • Create a FREE account to sign up for Digital Library content alerts and gain access to institutional subscriptions remotely.
Access This Article
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).
Access This Proceeding
Sign in or Create a personal account to Buy this article ($15 for members, $18 for non-members).
Access This Chapter

Access to SPIE eBooks is limited to subscribing institutions and is not available as part of a personal subscription. Print or electronic versions of individual SPIE books may be purchased via SPIE.org.