Robust and imperceptible image watermarking technique based on SVD, DCT, BEMD and PSO in wavelet domain

This article introduces a robust image watermarking primarily founded on DWT (discrete wavelet transform), BEMD (bi-dimensional empirical mode decomposition), DCT (discrete cosine transform), PSO (particle swarm optimization), and SVD (singular value decomposition). During the process of embedding, 2nd level DWT is used to decompose the cover image into sub-bands. DWT is also used for the decomposition of images for watermarking. Further, BEMD decomposition runs to implement on the selected band of DWT. For optimization, PSO is used for complex and multidimensional searches. Further DCT as well as SVD applied to the selected band. The embedding and scaling factors are embedded with the help of a security key. Further, this method is followed by using the inverse of ISVD, IDCT, IDWT, and IBEMD. The Watermark image is extracted by the extraction process. Experimental results show that the suggested technique is robust compared to several geometrical and non-geometrical attacks. Therefore, this proposed technique provides better visible quality and robustness against numerous attacks like salt and pepper, Gaussian filter, rotation, median filter, speckle, gamma correction, scaling, and shearing for gray scale images and provides the watermarked image with good quality.