A Watermarking Method for Selective Image Authentication Tollerant to JPEG Compression, Brightness and Contrast Adjustments
One of the most promising application of the digital watermarking is the selective image authentication (SIA) systems. In order to implement such a system one requires an embedding algorithm with an appropriate capacity. In addition, an embedding method is to be robust for the class of non-malicious manipulations which the SIA system is designed for. We propose the new method which has a significant embedding capacity while still being tolerant to JPEG compression, brightness and contrast adjustments. This was possible due to the extension of the well-known discrete wavelet transform embedding technique. We propose two-step embedding scheme and the use of image histogram equalisation and recovering operations. The experiment results show acceptable tolerance to JPEG compression, brightness and contrast adjustments with good visual quality in terms of PSNR just after embedding.