A blind chaos- based watermarking technique

This paper presents a robust blind frequency domain watermarking scheme based on chaotic maps. The proposed scheme embeds a black and white watermark logo in the midband components of a host image according to a discrete wavelet transform. Each watermark bit is embedded into a small submatrix of selected second level subbands of an image resulting from iterated applications of a two-dimensional discrete wavelet transform. This scheme embeds two copies of the watermark using two different methods, in two different subbands of the image. At the cost of embedding capacity, this results in improving the security and robustness of the watermarking scheme. Experimental results demonstrate that the suggested scheme provides imperceptibility and robustness against image processing attacks such as JPEG compression, low-pass filtering, median filtering, Gaussian noise, scaling, rotating, cropping, histogram equalization, and gamma correction. Experimental results also show superior robustness of the suggested scheme over existing algorithms with a similar approach. Copyright (c) 2013 John Wiley & Sons, Ltd.