Robust Color Image Watermarking Algorithm Based on 3D-DCT

For common color image watermarking algorithms embed watermarking only in luminance component or each color component separately lead to the watermarked image's transparency and robustness problems cannot achieve trade-off, a new RGB color image watermarking algorithm based on three-dimensional discrete cosine transform (3D-DCT) is proposed. Firstly, to enhance the security of the watermarking, the watermark image is processed by XOR encryption and Arnold scrambling. Secondly, the RGB color image is subdivided to non-overlapping blocks, and performs 3D-DCT for each block. Finally, the first coefficient of each block after performing 3D-DCT is modified by exploiting quantification method to embed watermarking. Experimental results show that the proposed algorithm has good transparency and robustness, and it has some practical for color image copyright protection applications.