Color image watermarking with adaptive strength of insertion

The paper presents a watermarking technique, specific to color images. The insertion and the detection are based on the 2D discrete wavelet transform, applied on each color component. Three color vectors are extracted from the wavelet coefficients. The insertion consists of modifying one vector for each location, with regard to the bit value and the vector triplet. The mark is extracted without the original image, by observing the scheme of each vector triplet. This new method has been shown to be resistant to JPEG compression, median filtering and noise adding. Moreover, each insertion is weighted by an adaptive strength, obtained by a retroactive process between the original and the watermarked images. This process allows optimizing the compromise between invisibility and robustness, considering the local image color content.