• Title/Summary/Keyword: Real-valued decoding key

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Optical Image Hiding Technique using Real-Valued Decoding Key (실수값 복원키를 이용한 광 영상 은닉 기술)

  • Cho, Kyu-Bo;Seo, Dong-Hoan;Choi, Eun-chang
    • IEMEK Journal of Embedded Systems and Applications
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    • v.6 no.3
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    • pp.168-173
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    • 2011
  • In this paper, an optical image hiding technique using real-valued decoding key is proposed. In the embedding process, a each zero-padded original image placed in a quadrants on an input plane is multiplied by a statistically independent random phase pattern and is Fourier transformed. An encoded image is obtained by taking the real-valued data from the Fourier transformed image. And then a phase-encoded pattern, used as a hidden image and a decoding key, is generated by the use of multiple phase wrapping from the encoded images. A transmitted image is made from the linear superposition of the weighted hidden images and a cover image. In reconstruction process, the mirror reconstructed images can be obtained at two quadrants by the inverse-Fourier transform of the product of the transmitted image and the decoding key. Computer simulation and optical experiment are demonstrated in order to confirm the proposed technique.

Efficient Optical Watermark Using Multiple Phase Wrapping and Real-Valued Functions (다중위상래핑과 실수값 함수를 이용한 효율적인 광 워터마킹)

  • Cho, Kyu-Bo;Seo, Dong-Hoan;Lee, Seung-Hee;Hong, Jae-Keun
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.46 no.3
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    • pp.10-19
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    • 2009
  • In this paper, an efficient optical watermark method using multiple phase wrapping and real-valued decoding key is proposed. In the embedding process, two zero-padded original images placed in two quadrants on input plane are multiplied with two statistically independent random phase patterns and are Fourier transformed, respectively. Two encoded images are obtained by taking the real-valued data from these Fourier transformed images. And then two phase-encoded patterns, used as a hidden image and a decoding key, are generated by the use of multiple phase wrapping from each of the encoded images. A transmitted image is made from the linear superposition of the weighted hidden images and a cover image. In reconstruction process, the mirror reconstructed images can be obtained at all quadrants by the inverse-Fourier transform of the product of the transmitted image and the decoding key. Computer simulation and optical experiment are demonstrated in order to confirm the proposed method.

Image Watermark Method Using Multiple Decoding Keys (다중 복호화 키들을 이용한 영상 워터마크 방법)

  • Lee, Hyung-Seok;Seo, Dong-Hoan;Cho, Kyu-Bo
    • Korean Journal of Optics and Photonics
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    • v.19 no.4
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    • pp.262-269
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    • 2008
  • In this paper, we propose an image watermark method using multiple decoding keys. The advantages of this method are that the multiple original images are reconstructed by using multiple decoding keys in the same watermark image, and that the quality of reconstructed images is clearly enhanced based on the idea of Walsh code without any side lobe components in the decoding process. The zero-padded original images, multiplied with random-phase pattern to each other, are Fourier transformed. Encoded images are then obtained by taking the real-valued data from these Fourier transformed images. The embedding images are obtained by the product of independent Walsh codes, and these spreaded phase-encoded images which are multiplied with new random-phase images. Also we obtain the decoding keys by multiplying these random-phase images with the same Walsh code images used in the embedding images. A watermark image is then made from the linear superposition of the weighted embedding images and a cover image, which is multiplied with a new independent Walsh code. The original image is simply reconstructed by the inverse-Fourier transform of the despreaded image of the multiplication between the watermark image and the decoding key. Computer simulations demonstrate the efficiency of the proposed watermark method with multiple decoding keys and a good robustness to the external attacks such as cropping and compression.