OSA's Digital Library

Journal of Display Technology

Journal of Display Technology


  • Vol. 8, Iss. 9 — Sep. 1, 2012
  • pp: 505–510

Optimization of Size of Pixel Blocks for Orthogonal Transform in Optical Watermarking Technique

Yasunori Ishikawa, Kazutake Uehira, and Kazuhisa Yanaka

Journal of Display Technology, Vol. 8, Issue 9, pp. 505-510 (2012)

View Full Text Article

Acrobat PDF (3776 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

  • Export Citation/Save Click for help


We previously proposed a novel technology with which the images of real objects with no copyright protection could contain invisible digital watermarking, using spatially modulated illumination. In this “optical watermarking” technology, we used orthogonal transforms, such as a discrete cosine transform (DCT) or a Walsh-Hadamard transform (WHT), to produce watermarked images, where 1-b binary information was embedded into each pixel block. In this paper, we propose an optimal condition for a technique of robust optical watermarking that varies the size of pixel blocks by using a trade-off in the efficiency of embedded watermarking. We conducted experiments where ${\hbox{4}}\times{\hbox{4}}$, ${\hbox{8}}\times{\hbox{8}}$, and ${\hbox{16}}\times{\hbox{16}}$ pixels were used in one block. A detection accuracy of 100% was obtained by using a block with ${\hbox{16}}\times{\hbox{16}}$ pixels when embedded watermarking was extremely weak, although the accuracy did not necessarily reach 100% by using blocks with ${\hbox{4}}\times{\hbox{4}}$ or ${\hbox{8}}\times{\hbox{8}}$ pixels under the same embedding conditions. We also examined the effectiveness of using a Haar discrete wavelet transform (Haar DWT) as an orthogonal transform under the same experimental condition, and the results showed that the accuracy of detection was slightly inferior to DCT and WHT under very weak embedding conditions. The results from experiments revealed the effectiveness of our new proposal.

© 2012 IEEE

Yasunori Ishikawa, Kazutake Uehira, and Kazuhisa Yanaka, "Optimization of Size of Pixel Blocks for Orthogonal Transform in Optical Watermarking Technique," J. Display Technol. 8, 505-510 (2012)

Sort:  Year  |  Journal  |  Reset


  1. I. J. Cox, J. Kilian, F. T. Leighton, T. Shamoon, "Secure spread spectrum watermarking for multimedia," IEEE Trans. Image Process. 6, 1673-1687 (1997).
  2. M. D. Swanson, M. Kobayashi, A. H. Tewfik, "Multimedia data-embedding and watermarking technologies," Proc. IEEE 86, 1064-1087 (1998).
  3. M. Hartung, M. Kutter, "Multimedia watermarking techniques," Proc IEEE 87, 1079-1107 (1999).
  4. G. C. Langelaar, I. Setyawan, R. L. Lagendij, "Watermarking digital image and video data," IEEE Signal Process. Mag. 17, 20-46 (2000).
  5. J. Haitsma, T. Kalker, "A watermarking scheme for digital cinema," proc. ICIP2001 (2001) pp. 487-489.
  6. "Digital cinema system specification V1.2," Digital Cinema Initiatives (2008).
  7. S. Goshi, H. Nakamura, H. Ito, R. Fujii, M. Suzuki, S. Takai, Y. Tani, "A new watermark surviving after re-shooting the images displayed on a screen," Proc. KES2005, LNAI3682 (2005) pp. 1099-1107.
  8. K. Okihara, Y. Inazumi, H. Kinoshita, "A watermark method that improve the relationship between of the number of embedded bits and image degradation," J. IEIJ 58, 1465-1467 (2004).
  9. T. Mizumoto, K. Matsui, "Robustness investigation of DCT digital watermark for printing and scanning," Trans. IEICE (A) J85-A, 451-459 (2002).
  10. M. Ejima, A. Miyazaki, "Digital watermark technique for hard copy image," Trans. IEICE (A) J82-A, 1156-1159 (1999).
  11. Y. Horiuchi, M. Muneyasu, "Information embedding to the printing images based on DCT," Proc. ITC-CSCC2004 (2004) pp. 7F3P50-1-4.
  12. Z. Liu, Multimedia Watermarking Techniques and Applications (Auerbach, 2006) pp. 289-305.
  13. K. Uehira, M. Suzuki, "Digital watermarking technique using brightness-modulated light," Proc. ICME2008 (2008) pp. 257-260.
  14. K. Uehira, Y. Ishikawa, K. Yanaka, "Optical watermarking robust to object with low-reflectance," Proc. ICME2009 (2009) pp. 1756-1759.
  15. Y. Ishikawa, K. Uehira, K. Yanaka, "Illumination watermarking technique using orthogonal transforms," Proc. IAS2009 (2009) pp. 257-260.
  16. Y. Ishikawa, K. Uehira, K. Yanaka, "Practical evaluation of illumination watermarking technique using orthogonal transforms," J. Display Technol. 6, 351-358 (2010).
  17. T. Yamada, S. Gohshi, I. Echizen, "Re-shooting prevention based on difference between sensory perceptions of humans and devices," Proc. ICIP 2010 (2010) pp. 993-996.
  18. Y. Ishikawa, K. Uehira, K. Yanaka, "Optical watermarking technique robust to geometrical distortion in image," Proc. ISSPIT2010 (2010) pp. 67-72.
  19. Y. Ishikawa, K. Uehira, K. Yanaka, "Embedding watermarking into real object image data using QR-code and optical watermarking technique," Proc. ICIPT2011 (2011) pp. 34-38.

Cited By

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited