Blind Image Watermarking Based on Discrete Hilbert Transform and Polar Decomposition

Abstract

Digital watermarking is a potent technique for digital right management of multimedia data. This paper aims to introduce a blind image watermarking algorithm using discrete Hilbert transform (DHT) and polar decomposition (PD). Initially, Gaussian map is utilized to preprocess the watermark image to enhance its security. Then the original image is segmented into red, green and blue channels. The blue channel of the original image is selected and it is divided into non-overlapping blocks. DHT is conducted on each block to obtain the DHT coefficients represented in matrix form. PD is then carried out to each of these matrices and watermark data is inserted into the positive semi-definite Hermitian matrix obtained from the DHT coefficients of each block by using an embedding operation. Experimental results specify that the proposed algorithm has excellent resistance to numerous attacks. In addition, it also provides good quality watermarked images. Moreover, it shows more excellent results than the recent techniques in respect of robustness and imperceptibility.