Semi fragile watermarking scheme for image recovery in wavelet domain

Image authentication watermarking scheme can substantially solve the security of digital images transmitted through insecure channel. In this paper we propose a semi-fragile watermarking scheme for image authentication, localizing and recovering. The approximation sub-band of the second Discrete Wavelet Transformation (DWT), LL2 is used as recovery watermark while the fifth approximation sub-band LL5 is used as authentication and localizing watermark. The two watermarks are embedded into the first approximation sub-band LL1 using the Quantization Index Modulation (QIM). To reduce the size of the recovery watermark, Data Representation through Combination (DRC) is practically used. The experimental results show that our proposed algorithm can resist JPEG compression and give an acceptable estimation of the watermarked image even after the watermarked image has been tampered.