A Semi-fragile Watermarking Scheme for Image Tamper Localization and Recovery

A novel semi-fragile watermarking scheme for Image tamper localization and recovery is proposed. The Logistic map is used to encrypt the feature extracted from the original image, then the generated watermark is embedded into the middle-frequency DCT coefficients of each block after being ordered in zigzag manner based on invariance properties of DCT coefficients before and after JPEG compressions. As for authentication, firstly, the feature information is extracted after decryption, and compared it with reconstructed feature information, then, the tamper matrix is generated. Finally, recover the invalid blocks by using bicubic interpolation. Experimental results illustrate that the watermarked image has good imperceptibility and can tolerate the common content-preserving image processing. It is also sensitive to malicious manipulations and can localize and recover tampered regions approximately.