Improved performance of image watermarking by reducing luminance bias

In this paper, an image watermarking based on the modification of image pixels is considered. Its performance is analyzed and discussed. Based on our analysis, a method based on the reduction of the luminance bias is then proposed in order to improve the watermark extraction performance. The experimental results obtained verify our proposed concept, and show the improvements in term of PSNR and NC of the proposed watermarking method, compared to the previous methods proposed. The robustness of the embedded watermark against various types of common image processing based attacks are also evaluated and compared.