Improved performance of image watermarking by removing luminance bias

A digital watermarking for color image based on the modification of image pixels is considered in this paper. Its performance is analyzed and the weakness in the watermark extraction method is addressed. Based on our analysis, a method based on the removal 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 method proposed in. The robustness of the embedded watermark against three different types of common image processing based attacks are also evaluated and compared.