Blind Watermarking Arithmetic for Color Image Based on Discrete Wavelet Transform

In this paper, we present a new watermarking arithmetic for color images based on discrete wavelet transform (DWT). First we transform the color space from RGB to YUV. After scrambling, the U component is transformed to the frequency spectrum by 3-level DWT. We take pseudo random sequence as the watermark, and insert it into the second and third high frequency bands. Linear correlation detector is used to detect the watermark, so the watermark can be detected without original image. We employ image scrambling technology to make the linear correlation detector in this watermarking system be optimal. The experimental results shows that the scheme has good transparency and robustness.