• Title/Summary/Keyword: Watermark weighting factor

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Digital Watermarking Based on Adaptive Threshold and Weighting Factor Decision Method (적응적 임계치와 가중치 결정 방법에 기반한 디지털 워터마킹)

  • Lim, Ho;Kim, Jin-Young
    • Proceedings of the IEEK Conference
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    • 2000.06d
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    • pp.123-126
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    • 2000
  • In this paper, we propose new watermarking technique using weighting factor decision method in the watermark embedding step and adaptive threshold decision method in the watermark extracting step. In our method, we are determined weighting factor in simple by calculating distance between pixel coefficient and neighborhood pixel coefficients and threshold is adaptively determined by searching the minimized extract error value using histogram of difference value.

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Still Image Watermarking in the DCT Domain Using the Human Visual System (DCT 영역에서의 인간의 시각적 특성을 이용한 정지 영상 워터마킹 방법)

  • Kwon O-Hyung;Park Rae-Hong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.12C
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    • pp.1214-1221
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    • 2005
  • In this paper, we propose a digital watermarking method for still images, in which the human visual system (HVS) is used in the discrete cosine transform (DCT) domain. The modulation transfer function (MTF) of the HVS model is employed to increase the invisibility of the inserted watermark in images. The proposed watermarking method is shown to be robust to several common image processing techniques, including lowpass filtering and cropping. Also, using the energy relationship of the DCT, we derive the equation that directly computes the watermark weighting factor in the DCT domain for the specified peak signal to noise ratio (PSNR) of the still image and the length of watermark to be inserted. The difference between desired PSNR and PSNR in spatial domain is within 0.07dB for the 7 test images.

Digital Image Watermarking Using Multiresolution Wavelet Transform (멀티해상도 웨이블릿 변환을 이용한 디지털 영상 워터마킹)

  • 이호준;고형화
    • Journal of Broadcast Engineering
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    • v.7 no.4
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    • pp.368-375
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    • 2002
  • In this paper, we apply multiresolution wavelet transform for the digital image watermarking. For better result, we insert watermark into the images and set a proper weighting factor for each subband based on HVS model. With proposed algorithm, we confirm that the image quality is satisfactory and this method outperforms the previous methods against image compression and cropping.