Abstract: An image watermarking algorithm based on subband transform is proposed. With an uniform multi-channel filter bank an image is transformed as a set of subband parts every one of which have unique frequency character, and some lower-middle subband parts are chose to embed watermark. The experimental results show that the proposed watermarking algorithm results in an almost invisible difference between the watermarked image and the original image, and it is robust to noise and JPEG lossy compression.

Key words: watermarking, filter bank, subband transform