Chaotic system for image tamper detection

Image watermarking techniques are specially used to provide copyright protection, owner’s identification, image authentication and tamper detection. Fragile watermarking is usually used for image authentication and tamper detection. In this paper, fragile watermarking scheme based on chaotic system has been proposed. Two dimensional Arnold’s cat map has been used to improve the security of the proposed watermarkingscheme. Arnold’s cat map is sensitive to the initial values.

This map is specially used to obtain the scrambled image by shuffling the pixel positions of the host image. Therefore the number of iterations and the initial values which are used to obtain scrambled image can be used as secret keys. The proposed scheme provides high security, extracts watermark from the tampered image and also localizes the tampered areas. Experimental results of proposed method have been compared with other existing two chaotic system based watermarking schemes. From the experimental results it can be seen that the proposedwatermarking scheme gives better results than other chaos basedwatermarking schemes.