Halftoning, Compression, and Cryptography

Enhancing registration tolerance of extended visual cryptography for natural images

[+] Author Affiliations
Mizuho Nakajima

Waseda University, School of International Liberal Studies, 1-7-14-4F Nishi-waseda, Shinjuku-ku, Tokyo 169-0051, Japan

Yasushi Yamaguchi

The University of Tokyo, Graduate School of Arts and Sciences, Department of Graphics and Computer Sciences, 3-8-1 Komaba, Meguro-ku, Tokyo?153-8902, Japan

J. Electron. Imaging. 13(3), 654-662 (Jul 01, 2004). doi:10.1117/1.1758729
History: Received Mar. 31, 2003; Revised Oct. 10, 2003; Revised Jan. 15, 2004; Accepted Jan. 16, 2004; Online July 29, 2004
Text Size: A A A

Extended visual cryptography [Ateniese et al. , Theor. Comput. Sci. 250, 143–161 (2001)] is a method that encodes a number of images so that when the images are superimposed, a hidden image appears while the original images disappear. The decryption is done directly by human eyes without cryptographic calculations. Our proposed system takes three natural images as input and generates two images that are modifications of two of the input pictures. The third picture is viewed by superimposing the two output images. A trade-off exists between the number of gray levels and the difficulty in stacking the two sheets. Our new approach enhances the registration tolerance to obtain the third image and reduces the difficulty of superimposing the image while allowing a variety of gray levels. It is done by extending dot-clustered subpixel arrangements and enabling continuous gray-scale subpixel values. The system has considerably enhanced tolerance to the registration error. We show this by superimposing the output by computer simulation and calculating the peak SNRs with the original images. © 2004 SPIE and IS&T.

© 2004 SPIE and IS&T

Topics

Cryptography

Citation

Mizuho Nakajima and Yasushi Yamaguchi
"Enhancing registration tolerance of extended visual cryptography for natural images", J. Electron. Imaging. 13(3), 654-662 (Jul 01, 2004). ; http://dx.doi.org/10.1117/1.1758729


Tables

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

PubMed Articles
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.