A new image watermarking algorithm based on wavelet transform

In this paper, we proposed a new non blind robust digital watermarking algorithm for embedding binary image watermark in grayscale images. For embedding procedure, three levels discrete wavelet transform of cover image is computed. Afterward the watermark image is added in the high-high (HH), low-high (LH) and high-low (HL) subbands using a threshold coefficients. The low-low (LL) subband coefficients are not used in embedding procedure because that the human visual system (HVS) is less sensitive to the small change in edges and textures of image. Comparing the performance of our method to other watermarking methods, the proposed method show good performance in terms of invisibility and robustness. Experimental results demonstrate that the proposed method has a good robustness against several attacks such as: noise addition, histogram equalization, gamma correction, JPEG compression, cropping and randomly line and column removal.