  Digital watermarking is an effective way to protect copyright. In this paper,
a robust watermarking algorithm based on wavelet transformation is proposed
which can confirm the copyright without original image. The wavelet
transformation technique is effective in image analyzing and processing. Thus
the color-image watermark algorithm based on discrete wavelet transformation
(DWT) begins to draw an increasing attention. In the proposed approach, the
watermark Encrypt by Arnold transform and the host image is converted into the
YCbCr color space. Then its Y channel decomposed into wavelet coefficients and
the selected approximation coefficients are quantized and then their least
significant bit of the quantized coefficients is replaced by the Encrypted
watermark using LSB insertion technique. The experimental results show that
watermark embedded by this algorithm is of better robustness and extra
imperceptibility and robustness against wavelet compression compared to the
traditional embedding methods in RGB color space.
