A Simple Digital Watermarking by the Adaptive Bit-labeling Scheme

Based on integer wavelet transform (IWT), this study proposes a novel data hiding technique via the adaptive bit-labeling scheme. The proposed method includes bit-marking, modulus-2, and coefficient-bias steps. More specifically, a small (primary) watermark is first embedded in the three high subbands of the L1 IWT by bit-marking as well as in the L2 and L3 IWT by modulus-2. A large message, which is also known as the secondary watermark, is then hidden in the high subbands of the L1 IWT using the coefficient-bias. To promote robustness performance, instead of hiding bits directly in the blocks, the authors use an adaptive bit-labeling scheme to a block, which could correctly signify the hidden bits at the receiver. Simulations show that the primary watermark hidden in stego-images generated by the proposed method are robust against manipulations such as JPEG2000, JPEG, cropping, (color) quantization, noise additions, low-pass filtering, (edge) sharpening, brightness, contrast, winding and inverting. Experiments also confirm that under the condition of attacking-free the secondary watermark can be successfully extracted by the decoder. Moreover, the perceived quality of the resulting images is good.